From c1f069b713ac255140605badda0eb505a3d45dea Mon Sep 17 00:00:00 2001 From: Oscar Arbelaez Date: Sat, 15 Feb 2025 14:55:11 +0000 Subject: [PATCH 1/5] Start model validating --- src/bibx/__init__.py | 12 +++++++++- src/bibx/builders/scopus_csv.py | 42 +++++++++++++++++++++++++++++++++ src/bibx/cli.py | 11 +++++++-- 3 files changed, 62 insertions(+), 3 deletions(-) create mode 100644 src/bibx/builders/scopus_csv.py diff --git a/src/bibx/__init__.py b/src/bibx/__init__.py index 96ddce5..b1e48f6 100644 --- a/src/bibx/__init__.py +++ b/src/bibx/__init__.py @@ -7,6 +7,7 @@ from bibx.article import Article from bibx.builders.openalex import EnrichReferences, OpenAlexCollectionBuilder from bibx.builders.scopus_bib import ScopusBibCollectionBuilder +from bibx.builders.scopus_csv import ScopusCsvCollectionBuilder from bibx.builders.scopus_ris import ScopusRisCollectionBuilder from bibx.builders.wos import WosCollectionBuilder from bibx.collection import Collection @@ -56,6 +57,15 @@ def read_scopus_ris(*files: TextIO) -> Collection: return ScopusRisCollectionBuilder(*files).build() +def read_scopus_csv(*files: TextIO) -> Collection: + """Take any number of csv files from scopus and generates a collection. + + :param files: Scopus csv files open. + :return: the collection + """ + return ScopusCsvCollectionBuilder(*files).build() + + def read_wos(*files: TextIO) -> Collection: """Take any number of wos text files and returns a collection. @@ -67,7 +77,7 @@ def read_wos(*files: TextIO) -> Collection: def read_any(file: TextIO) -> Collection: """Try to read a file with the supported formats.""" - for handler in (read_wos, read_scopus_ris, read_scopus_bib): + for handler in (read_wos, read_scopus_ris, read_scopus_bib, read_scopus_csv): try: return handler(file) except BibXError as e: diff --git a/src/bibx/builders/scopus_csv.py b/src/bibx/builders/scopus_csv.py new file mode 100644 index 0000000..49e771e --- /dev/null +++ b/src/bibx/builders/scopus_csv.py @@ -0,0 +1,42 @@ +"""CSV based builder for Scopus data.""" + +import csv +from typing import Annotated, TextIO + +from pydantic import BaseModel, Field +from pydantic.functional_validators import BeforeValidator + +from bibx.collection import Collection + +from .base import CollectionBuilder + + +class Row(BaseModel): + """Row model for Scopus CSV data.""" + + authors: Annotated[ + list[str], + Field(validation_alias='"Authors"'), + BeforeValidator(lambda x: x.strip().split("; ")), + ] + title: Annotated[str, Field(validation_alias="Title")] + year: Annotated[int, Field(validation_alias="Year")] + + +class ScopusCsvCollectionBuilder(CollectionBuilder): + """Builder for Scopus data from CSV files.""" + + def __init__(self, *files: TextIO) -> None: + self._files = files + for file in self._files: + file.seek(0) + + def build(self) -> Collection: + """Build the collection.""" + for file in self._files: + reader = csv.DictReader(file) + print(reader.fieldnames) + for row in reader: + datum = Row.model_validate(row) + print(datum.model_dump_json(indent=2)) + return Collection(articles=[]) diff --git a/src/bibx/cli.py b/src/bibx/cli.py index 559c223..dce6d84 100644 --- a/src/bibx/cli.py +++ b/src/bibx/cli.py @@ -11,6 +11,7 @@ query_openalex, read_any, read_scopus_bib, + read_scopus_csv, read_scopus_ris, read_wos, ) @@ -28,6 +29,7 @@ class Format(Enum): WOS = "wos" RIS = "ris" BIB = "bib" + CSV = "csv" @app.command() @@ -41,12 +43,17 @@ def describe(format: Format, filename: str) -> None: if format == Format.RIS: with open(filename) as f: c = read_scopus_ris(f) - rprint(":boom: the file satisfies the ISI WOS format") + rprint(":boom: the file satisfies the scopus RIS format") rprint(f"There are {len(c.articles)} records parsed") if format == Format.BIB: with open(filename) as f: c = read_scopus_bib(f) - rprint(":boom: the file satisfies the ISI WOS format") + rprint(":boom: the file satisfies the scopus BIB format") + rprint(f"There are {len(c.articles)} records parsed") + if format == Format.CSV: + with open(filename) as f: + c = read_scopus_csv(f) + rprint(":boom: the file satisfies the scopus CSV format") rprint(f"There are {len(c.articles)} records parsed") From afd83a27858c69a1a3ffa7c61c5bbc7ae71be852 Mon Sep 17 00:00:00 2001 From: Oscar Arbelaez Date: Sat, 15 Feb 2025 18:19:48 +0000 Subject: [PATCH 2/5] Draft scopus csv parser --- docs/examples/scopus.csv | 582 ++++++++++++++++++++++++++++++++ src/bibx/builders/scopus_csv.py | 121 ++++++- 2 files changed, 694 insertions(+), 9 deletions(-) create mode 100644 docs/examples/scopus.csv diff --git a/docs/examples/scopus.csv b/docs/examples/scopus.csv new file mode 100644 index 0000000..4f74826 --- /dev/null +++ b/docs/examples/scopus.csv @@ -0,0 +1,582 @@ +"Authors","Author full names","Author(s) ID","Title","Year","Source title","Volume","Issue","Art. No.","Page start","Page end","Page count","Cited by","DOI","Link","Affiliations","Authors with affiliations","Abstract","Author Keywords","Index Keywords","Molecular Sequence Numbers","Chemicals/CAS","Tradenames","Manufacturers","Funding Details","Funding Texts","References","Correspondence Address","Editors","Publisher","Sponsors","Conference name","Conference date","Conference location","Conference code","ISSN","ISBN","CODEN","PubMed ID","Language of Original Document","Abbreviated Source Title","Document Type","Publication Stage","Open Access","Source","EID" +"Gong B.; Wang L.; Wang S.; Yu Z.; Xiong L.; Xiong R.; Liu Q.; Zhang Y.","Gong, Bin (57321683800); Wang, Luowen (58115311900); Wang, Sunan (58851041300); Yu, Ziyang (57195288051); Xiong, Lun (55210315300); Xiong, Rui (57216372992); Liu, Qingbo (57196046069); Zhang, Yue (57218772783)","57321683800; 58115311900; 58851041300; 57195288051; 55210315300; 57216372992; 57196046069; 57218772783","Optimizing skyrmionium movement and stability via stray magnetic fields in trilayer nanowire constructs","2024","Physical Chemistry Chemical Physics","26","5","","4716","4723","7","0","10.1039/d3cp05340g","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183479140&doi=10.1039%2fd3cp05340g&partnerID=40&md5=86cd975771eca2c633a84c5da376f841","Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Fujian Provincial Key Laboratory of Semiconductors and Applications, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen, 361005, China; Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, China; School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China","Gong B., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China, Fujian Provincial Key Laboratory of Semiconductors and Applications, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen, 361005, China; Wang L., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Wang S., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Yu Z., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Xiong L., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Xiong R., Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, China; Liu Q., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Zhang Y., School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China","Skyrmioniums, known for their unique transport and regulatory properties, are emerging as potential cornerstones for future data storage systems. However, the stability of skyrmionium movement faces considerable challenges due to the skyrmion Hall effect, which is induced by deformation. In response, our research introduces an innovative solution: we utilized micro-magnetic simulations to create a sandwiched trilayer nanowire structure augmented with a stray magnetic field. This combination effectively guides the skyrmionium within the ferromagnetic (FM) layer. Our empirical investigations reveal that the use of a stray magnetic field not only reduces the size of the skyrmionium but also amplifies its stability. This dual-effect proficiently mitigates the deformation of skyrmionium movement and boosts their thermal stability. We find these positive outcomes are most pronounced at a particular intensity of the stray magnetic field. Importantly, the required stray magnetic field can be generated using a heavy metal (HM1) layer of suitable thickness, rendering the practical application of this approach plausible in real-world experiments. Additionally, we analyze the functioning mechanism based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation. We also develop a deep spiking neural network (DSNN), which achieves a remarkable recognition accuracy of 97%. This achievement is realized through supervised learning via the spike timing dependent plasticity rule (STDP), considering the nanostructure as an artificial synapse device that corresponds to the electrical properties of the nanostructure. In conclusion, our study provides invaluable insights for the design of innovative information storage devices utilizing skyrmionium technology. By tackling the issues presented by the skyrmion Hall effect, we outline a feasible route for the practical application of this advanced technology. Our research, therefore, serves as a robust platform for continued investigations in this field. © 2024 The Royal Society of Chemistry.","","Hall effect; Nanowires; Neural networks; Stability; heavy metal; nanomaterial; nanowire; Data storage systems; Empirical investigation; Ferromagnetic layers; Innovative solutions; Micromagnetic simulations; Nanowire structures; Regulatory properties; Skyrmions; Stray magnetic fields; Trilayers; article; data storage device; electric potential; information storage; learning; magnetic field; simulation; spiking neural network; synapse; thermostability; thickness; Heavy metals","","","","","Graduate Innovative Fund of Wuhan Institute of Technology, (CX2021376); National Natural Science Foundation of China, NSFC, (11804211, 12104348, 51971098, 52201213, 91963207); National Natural Science Foundation of China, NSFC; Department of Science and Technology, Hubei Provincial People's Government, (2019CFB435); Department of Science and Technology, Hubei Provincial People's Government; National Key Research and Development Program of China, NKRDPC, (2022YFE0103300); National Key Research and Development Program of China, NKRDPC","The authors acknowledge financial support from the National Key Research and Development Program of China (no. 2022YFE0103300), the National Natural Science Foundation of China (no. 12104348, 51971098, 52201213, and 11804211), the Major Research plan of the National Natural Science Foundation of China (no. 91963207), Science and Technology Department of Hubei Province (no. 2019CFB435), and the Graduate Innovative Fund of Wuhan Institute of Technology (no. CX2021376).","Kang W., Huang Y., Zhang X., Zhou Y., Zhao W., Proc. IEEE, 104, pp. 2040-2061, (2016); Nagaosa N., Tokura Y., Nat. Nanotechnol., 8, pp. 899-911, (2013); Wiesendanger R., Nat. Rev. Mater., 1, pp. 1-11, (2016); Mochizuki M., Seki S., Phys. Rev. B: Condens. Matter Mater. Phys., 87, (2013); Okamura Y., Kagawa F., Mochizuki M., Kubota M., Seki S., Ishiwata S., Kawasaki M., Onose Y., Tokura Y., Nat. Commun., 4, (2013); Zhang X., Zhou Y., Ezawa M., Zhao G., Zhao W., Sci. Rep., 5, (2015); Fert A., Cros V., Sampaio J., Nat. Nanotechnol., 8, pp. 152-156, (2013); Kang W., Zheng C., Huang Y., Zhang X., Zhou Y., Lv W., Zhao W., IEEE Electron Device Lett., 37, pp. 924-927, (2016); Huang Y., Kang W., Zhang X., Zhou Y., Zhao W., Nanotechnology, 28, (2017); Litzius K., Lemesh I., Kruger B., Bassirian P., Caretta L., Richter K., Buttner F., Sato K., Tretiakov O.A., Forster J., Nat. Phys., 13, pp. 170-175, (2017); Jiang W., Zhang X., Yu G., Zhang W., Wang X., Benjamin Jungfleisch M., Pearson J.E., Cheng X., Heinonen O., Wang K.L., Nat. Phys., 13, pp. 162-169, (2017); Zang J., Mostovoy M., Han J.H., Nagaosa N., Phys. Rev. Lett., 107, (2011); Neubauer A., Pfleiderer C., Binz B., Rosch A., Ritz R., Niklowitz P., Boni P., Phys. Rev. Lett., 102, (2009); Lee M., Kang W., Onose Y., Tokura Y., Ong N.P., Phys. Rev. Lett., 102, (2009); Bruno P., Dugaev V., Taillefumier M., Phys. Rev. Lett., 93, (2004); Kolesnikov A.G., Stebliy M.E., Samardak A.S., Ognev A.V., Sci. Rep., 8, (2018); Zhang Y., Luo S., Yan B., Ou-Yang J., Yang X., Chen S., Zhu B., You L., Nanoscale, 9, pp. 10212-10218, (2017); Finazzi M., Savoini M., Khorsand A., Tsukamoto A., Itoh A., Duo L., Kirilyuk A., Rasing T., Ezawa M., Phys. Rev. Lett., 110, (2013); Zhang X., Xia J., Zhou Y., Wang D., Liu X., Zhao W., Ezawa M., Phys. Rev. B, 94, (2016); Gobel B., Schaffer A.F., Berakdar J., Mertig I., Parkin S.S., Sci. Rep., 9, (2019); Shen L., Li X., Zhao Y., Xia J., Zhao G., Zhou Y., Phys. Rev. Appl., 12, (2019); Wang J., Xia J., Zhang X., Zheng X., Li G., Chen L., Zhou Y., Wu J., Yin H., Chantrell R., Appl. Phys. Lett., 117, (2020); Liang X., Zhang X., Shen L., Xia J., Ezawa M., Liu X., Zhou Y., Phys. Rev. B, 104, (2021); Vidal-Silva N., Riveros A., Escrig J., J. Magn. Magn. Mater., 443, pp. 116-123, (2017); Guslienko K.Y., IEEE Magnetics Lett., 6, pp. 1-4, (2015); Yu Z., Gong B., Wei C., Wang R., Xiong L., You L., Zhang Y., Liang S., Lu Z., Xiong R., Appl. Phys. Lett., 121, (2022); Leonov A.O., Mostovoy M., Nat. Commun., 6, (2015); Lin S.-Z., Hayami S., Phys. Rev. B, 93, (2016); Chen R., Li C., Li Y., Miles J.J., Indiveri G., Furber S., Pavlidis V.F., Moutafis C., Phys. Rev. Appl., 14, (2020); Tejo F., Riveros A., Escrig J., Guslienko K., Chubykalo-Fesenko O., Sci. Rep., 8, (2018); Moreau-Luchaire C., Moutafis C., Reyren N., Sampaio J., Vaz C., Van Horne N., Bouzehouane K., Garcia K., Deranlot C., Warnicke P., Nat. Nanotechnol., 11, pp. 444-448, (2016); Buttner F., Lemesh I., Beach G.S., Sci. Rep., 8, (2018); Bernand-Mantel A., Camosi L., Wartelle A., Rougemaille N., Darques M., Ranno L., SciPost Phys., 4, (2018); Woo S., Litzius K., Kruger B., Im M.-Y., Caretta L., Richter K., Mann M., Krone A., Reeve R.M., Weigand M., Nat. Mater., 15, pp. 501-506, (2016); Ikka M., Takeuchi A., Mochizuki M., Phys. Rev. B, 98, (2018); Mochizuki M., Appl. Phys. Lett., 111, (2017); Hayami S., Phys. Rev. B, 103, (2021); Zhang Y., Luo S., Yang X., Yang C., Sci. Rep., 7, (2017); Brown W.F., Phys. Rev., 130, (1963); Wang M., Cai W., Zhu D., Wang Z., Kan J., Zhao Z., Cao K., Wang Z., Zhang Y., Zhang T., Nat. Electron., 1, pp. 582-588, (2018); Zhou Y., Ezawa M., Nat. Commun., 5, (2014); Zhou Y., Iacocca E., Awad A.A., Dumas R.K., Zhang F.C., Braun H.B., Akerman J., Nat. Commun., 6, (2015); Woo S., Mann M., Tan A.J., Caretta L., Beach G.S.D., Appl. Phys. Lett., 105, (2014); Kang W., Huang Y., Zhang X., Zhou Y., Zhao W., Proc. IEEE, 104, pp. 2040-2061, (2016); Iwasaki J., Koshibae W., Nagaosa N., Nano Lett., 14, pp. 4432-4437, (2014); Iwasaki J., Mochizuki M., Nagaosa N., Nat. Nanotechnol., 8, pp. 742-747, (2013); Sampaio J., Cros V., Rohart S., Thiaville A., Fert A., Nat. Nanotechnol., 8, pp. 839-844, (2013); Tao J., Zhou J., Yao Z., Jiao Z., Wei B., Tan R., Li Z., Carbon, 172, pp. 542-555, (2021); Diehl P.U., Cook M., Front. Comput. Neurosci., 9, (2015); Prezioso M., Mahmoodi M., Bayat F.M., Nili H., Kim H., Vincent A., Strukov D., Nat. Commun., 9, (2018)","; Q. Liu; Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; email: tommyu91@163.com","","Royal Society of Chemistry","","","","","","14639076","","PPCPF","38251958","English","Phys. Chem. Chem. Phys.","Article","Final","","Scopus","2-s2.0-85183479140" +"Zeng Z.; Gao S.-P.; Guo Y.-X.","Zeng, Zequn (58246737900); Gao, Si-Ping (58118037500); Guo, Yong-Xin (57198926864)","58246737900; 58118037500; 57198926864","A Novel Design Methodology for MSSW Transmission Lines Without Iteratively Solving Maxwell-Landau-Lifshitz-Gilbert Equation","2024","2024 IEEE MTT-S International Wireless Symposium, IWS 2024 - Proceedings","","","","","","","0","10.1109/IWS61525.2024.10713487","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85208923844&doi=10.1109%2fIWS61525.2024.10713487&partnerID=40&md5=b014b0b2c43c0faa409d738b6193e977","National University of Singapore, Department of Electrical and Computer Engineering, Singapore","Zeng Z., National University of Singapore, Department of Electrical and Computer Engineering, Singapore; Gao S.-P., National University of Singapore, Department of Electrical and Computer Engineering, Singapore; Guo Y.-X., National University of Singapore, Department of Electrical and Computer Engineering, Singapore","Magnetostatic surface wave (MSSW) has unique features of unidirectional propagation, slow group velocity, and magnetic tunability, leading to wide applications in microwave devices and components like magnetostatic surface wave transmission lines (MSSW-TLs) for analog signal processing. Due to the strong interaction between MSSW and RF signals, solving the coupled Maxwell-Landau-Lifshitz-Gilbert (Maxwell-LLG) equations is necessary in modeling MSSW devices, which is however resource-intensive and time-consuming. To avoid solving the coupled equations, in this work, a novel design methodology based on the analogy between magnetic biasing and amplification is proposed for MSSW-TLs. The performance of a biased MSSW-TL can thus be easily predicted by its unbiased performance (Maxwell's equation only) with an amplification factor, leading to a rapid optimization process that is accelerated by ~100. An yttrium iron garnet (YIG)-based MSSW-TL prototype is successfully designed using the proposed method. The experimental data proves the effectiveness of the proposed design methodology. © 2024 IEEE.","Electromagnetic coupling; magnetostatic surface wave (MSSW); Maxwell-LLG; termination design; yttrium iron garnet (YIG)","Integrated circuit design; Magnetostatics; Masers; Maxwell equations; Structural analysis; Yttrium; Electromagnetics; Landau-Lifshitz-Gilbert; Magnetostatic surface wave; Magnetostatic surface waves; Maxwell-landau-lifshitz-gilbert; Novel design methodology; Termination design; Transmission-line; Yttrium iron garnet; Yttrium iron garnets; Yttrium iron garnet","","","","","","","Yu H., Kelly O., Cros V., Bernard R., Bortolotti P., Anane A., Brandl F., Huber R., Stasinopoulos I., Grundler D., Magnetic thin-film insulator with ultra-low spin wave damping for coherent nanomagnonics, Sci. Rep., 4, (2014); Zeng Z., Gao S.-P., Guo Y.-X., Measurement-Based RLGC Extraction for Improving YIG-Based Frequency Selective Limiter Modelling, 2022 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWSAMP), pp. 1-3, (2022); Stancil D.D., Theory of Magnetostatic Waves, (1993); Wu Y.S., Rosenbaum F.J., Microwave propagation in magnetized ferrite-dielectric composite transmission lines, J. Appl. Phys., 45, 6, pp. 2512-2520, (1974); Fetisov Y.K., Kabos P., Patton C.E., Active magnetostatic wave delay line, IEEE Trans. Magn., 34, 1, pp. 259-271, (1998); Zhang Y., Et al., Nonreciprocal Isolating Bandpass Filter with Enhanced Isolation Using Metallized Ferrite, IEEE Trans. Microw. Theory Techn., 68, 12, pp. 5307-5316, (2020); Adam J.D., Stitzer S.N., MSW frequency selective limiters at UHF, IEEE Trans. Magn., 40, 4, pp. 2844-2846, (2004); Ganguly A.K., Webb D.C., Microstrip Excitation of Magnetostatic Surface Waves: Theory and Experiment, IEEE Trans. Microw. Theory Techn., 23, 12, pp. 998-1006, (1975); Aziz M.M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, Prog. Electromagn. Res. B, 15, pp. 1-29, (2009); Wu J., Yang X., Beguhn S., Lou J., Sun N.X., Nonreciprocal Tunable Low-Loss Bandpass Filters with Ultra-Wideband Isolation Based on Magnetostatic Surface Wave, IEEE Trans. Microw. Theory Techn., 60, 12, pp. 3959-3968, (2012); Adam J.D., Winter F., Magnetostatic Wave Frequency Selective Limiters, IEEE Trans. Magn., 49, 3, pp. 956-962, (2013); Chumak A., Vasyuchka V.I., Serga A.A., Et al., Magnon spintronics, Nat. Phys., 11, 6, pp. 453-461, (2015); Bongianni W.L., Magnetostatic propagation in a dielectric layered structure, J. Appl. Phys., 43, 6, pp. 2541-2548, (1972); Yao Z., Tok R.U., Itoh T., Wang Y.E., A Multiscale Unconditionally Stable Time-Domain (MUST) Solver Unifying Electrodynamics and Micromagnetics, IEEE Trans. Microw. Theory Techn., 66, 6, pp. 2683-2696, (2018)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Microwave Theory and Techniques Society; Microwave Society of the Chinese Institute of Electronics","11th IEEE MTT-S International Wireless Symposium, IWS 2024","16 May 2024 through 19 May 2024","Beijing","203612","","979-835038999-9","","","English","IEEE Mtt-S Int. Wirel. Symp., IWS - Proc.","Conference paper","Final","","Scopus","2-s2.0-85208923844" +"Song C.; Han Z.; Zhou J.; Wang X.; Zhang L.; Ma Z.; Ma L.; Zheng F.","Song, Chengji (57669436900); Han, Zeyu (57482350300); Zhou, Jie (57667777000); Wang, Xuan (55953976900); Zhang, Luran (35199080900); Ma, Zhi (56525726300); Ma, Li (55987840500); Zheng, Fu (35207903300)","57669436900; 57482350300; 57667777000; 55953976900; 35199080900; 56525726300; 55987840500; 35207903300","Regulation of static and dynamic magnetic properties of amorphous FeCoZr composition gradient films by Zr doping","2023","AIP Advances","13","12","125109","","","","0","10.1063/5.0176549","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85180758590&doi=10.1063%2f5.0176549&partnerID=40&md5=fdfbf0684505f955ff1485158cffe67a","School of Physics, Ningxia University, Yinchuan, 750021, China; Department of Physics, School of Science, Lanzhou University of Technology, Lanzhou, 730050, China; School of Materials and Energy, Yunnan University, Kunming, 650091, China","Song C., School of Physics, Ningxia University, Yinchuan, 750021, China; Han Z., School of Physics, Ningxia University, Yinchuan, 750021, China; Zhou J., School of Physics, Ningxia University, Yinchuan, 750021, China; Wang X., Department of Physics, School of Science, Lanzhou University of Technology, Lanzhou, 730050, China; Zhang L., School of Materials and Energy, Yunnan University, Kunming, 650091, China; Ma Z., School of Physics, Ningxia University, Yinchuan, 750021, China; Ma L., School of Physics, Ningxia University, Yinchuan, 750021, China; Zheng F., School of Physics, Ningxia University, Yinchuan, 750021, China","A series of amorphous FeCoZr composition gradient monolayer films with varying Zr contents was prepared on the Si(100) substrate using RF magnetron sputtering. The effects of the Zr sputtering power PZr on the static and dynamic magnetic properties of FeCoZr films were systematically investigated. The results demonstrate that the introduction of the Zr element as a composition gradient into FeCo films not only improves the soft magnetic properties of the films but also enhances their in-plane uniaxial magnetic anisotropy. In particular, the doping of Zr elements leads to the destruction of FeCo lattice, inducing a transformation of the films from polycrystalline to amorphous state, resulting in a significant decrease in coercivity (Hc reduced by 82%) and surface roughness (Ra reduced by 78%). In addition, as PZr increases from 30 to 70 W, the anisotropy fields Hk of the films increase from 128 to 340 Oe, and the resonance frequency fr increases from 4.24 to 5.23 GHz. By fitting the permeability spectrum using the LLG equation, it is found that FeCoZr composition gradient films exhibit a lower damping coefficient α of around 0.011–0.014, indicating the reduction of energy loss during magnetization dynamics. These findings highlight the potential applications of FeCoZr composition gradient films in the field of high-frequency microwaves. © 2023 Author(s).","","Binary alloys; Energy dissipation; Iron alloys; Magnetic anisotropy; Magnetron sputtering; Semiconductor doping; Surface roughness; Ternary alloys; Composition gradient; FeCo films; Gradient film; Monolayer film; R.F. magnetron sputtering; Soft-magnetic properties; Sputtering power; Statics and dynamics; Uniaxial magnetic anisotropy; Zr-doping; Cobalt alloys","","","","","National Natural Science Foundation of China, NSFC, (11964027, 52261036); Natural Science Foundation of Ningxia Province, (2023AAC03006, 2023AAC03079)","This work was supported by the Natural Science Foundation of Ningxia (Grant Nos. 2023AAC03079 and 2023AAC03006) and the National Natural Science Foundation of China (Grant Nos. 11964027 and 52261036). ","Scheunert G., Heinonen O., Hardeman R., Lapicki A., Gubbins M., Bowman R.M., A review of high magnetic moment thin films for microscale and nanotechnology applications, Appl. Phys. Rev., 3, 1, (2016); Barranco A., Borras A., Gonzalez-Elipe A.R., Palmero A., Perspectives on oblique angle deposition of thin films: From fundamentals to devices, Prog. Mater. Sci., 76, pp. 59-153, (2016); Cronin D., Lordan D., Wei G., McCloskey P., Mathuna C.O., Masood A., Soft magnetic nanocomposite CoZrTaB–SiO2 thin films for high-frequency applications, J. Appl. Phys., 127, 24, (2020); Tang X.L., Yu Y., Su H., Zhang H.W., Zhong Z.Y., Jing Y.L., Improving the high-frequency magnetic properties of as-deposited CoFe films by ultra-low gas pressure, J. Mater. Sci., 53, 5, pp. 3573-3580, (2017); Masood A., McCloskey P., Mathuna C.O., Kulkarni S., Tailoring the ultra-soft magnetic properties of sputtered FineMET thin films for high-frequency power applications, J. Phys.: Conf. Ser., 903, (2017); Dev A.S., Bera A.K., Gupta P., Srihari V., Pandit P., Betker M., Schwartzkopf M., Roth S.V., Kumar D., Oblique angle deposited FeCo multilayered nanocolumnar structure: Magnetic anisotropy and its thermal stability in polycrystalline thin films, Appl. Surf. Sci., 590, (2022); Li X., Wen C.Y., Yang L.T., Zhang R.X., Li X.H., Li Y.S., Che R.C., MXene/FeCo films with distinct and tunable electromagnetic wave absorption by morphology control and magnetic anisotropy, Carbon, 175, pp. 509-518, (2021); Yang F.J., Min J.J., Li J.H., Chen H.B., Liu D.G., Li W.J., Chen X.Q., Yang C.P., The influence of film composition and annealing temperature on the; microstructure and magnetic properties of FeCo thin films, J. Mater. Sci.: Mater. Electron., 28, 16, pp. 11733-11737, (2017); Wang X., Zheng F., Liu Z.Y., Liu X.X., Wei D., Wei F.L., Preparation of soft magnetic FeCo-based films for writers, J. Appl. Phys., 105, 7, (2009); Anthony R., Wang N.N., Casey D.P., Mathuna C.O., Rohan J.F., MEMS based fabrication of high-frequency integrated inductors on Ni-Cu-Zn ferrite substrates, J. Magn. Magn. Mater., 406, pp. 89-94, (2016); Wu H., Khdour M., Apsangi P., Yu H.B., High-frequency magnetic thin-film inductor integrated on flexible organic substrates, IEEE Trans. Magn., 53, 11, pp. 1-7, (2017); Wu H., Lekas M., Davies R., Shepard K.L., Sturcken N., Integrated transformers with magnetic thin films, IEEE Trans. Magn., 52, 7, pp. 1-4, (2016); Sai Ram B., Paul A.K., Kulkarni S.V., Soft magnetic materials and their applications in transformers, J. Magn. Magn. Mater., 537, (2021); Kurlyandskaya G.V., Shcherbinin S.V., Volchkov S.O., Bhagat S.M., Calle E., Perez R., Vazquez M., Soft magnetic materials for sensor applications in the high frequency range, J. Magn. Magn. Mater., 459, pp. 154-158, (2018); Peng Y.J., Rahman B.M.F., Wang T.X., Nowrin C., Ali M., Wang G.A., Engineered smart substrate with embedded patterned permalloy thin film for radio frequency applications, J. Appl. Phys., 117, 17, (2015); Wolloch M., Suess D., Strain-induced control of magnetocrystalline anisotropy energy in FeCo thin films, J. Magn. Magn. Mater., 522, (2021); Yang W.J., Liu J.J., Yu X.F., Wang G., Zheng Z.G., Guo J.P., Chen D.Y., Qiu Z.G., Zeng D.C., The preparation of high saturation magnetization and low coercivity FeCo soft magnetic thin films via controlling the thickness and deposition temperature, Materials, 15, 20, (2022); Baco S., Abbas Q.A., Hayward T.J., Morley N.A., An investigation on the mechanical properties of soft magnetostrictive FeCoCr films by nanoindentation, J. Alloys Compd., 881, (2021); Cabral L., Aragon F.H., Villegas-Lelovsky L., Lima M.P., Macedo W.A.A., Da Silva J.L.F., Tuning the magnetic properties of FeCo thin films through the magnetoelastic effect induced by the Au underlayer thickness, ACS Appl. Mater. Interfaces, 11, 1, pp. 1529-1537, (2019); Wu Y.P., Yang Y., Yang Z.H., Ma F., Zong B.Y., Ding J., Tuning microwave magnetic properties of FeCoN thin films by controlling dc deposition power, J. Appl. Phys., 116, 9, (2014); Xu F., Liao Z.Q., Huang Q.J., Ong C.K., Li S.D., Influence of sputtering gas pressure on high-frequency soft magnetic properties of FeCoN thin film, IEEE Trans. Magn., 47, 10, pp. 3921-3923, (2011); Cao D.R., Cheng X.H., Feng H.M., Jin C.D., Zhu Z.T., Pan L.N., Wang Z.K., Wang J.B., Liu Q.F., Investigation on the structure and dynamic magnetic properties of FeCo films with different thicknesses by vector network analyzer and electron spin resonance spectroscopy, J. Alloys Compd., 688, pp. 917-922, (2016); Platt C.L., Minor N.K., Klemmer T.J., Magnetic and structural properties of FeCoB thin films, IEEE Trans. Magn., 37, pp. 2302-2304, (2001); Hasegawa T., Seki Y., TEM-based crystal structure analysis of body-centered tetragonal structure in non-epitaxial FeCo film with added V and N, Mater. Lett., 313, (2022); Li T.Y., Liu X.Y., Li J.W., Pan L.N., He A.N., Dong Y.Q., Microstructure and magnetic properties of FeCoHfN thin films deposited by DC reactive sputtering, J. Magn. Magn. Mater., 547, (2022); Li J.C., Zhan Q.F., Zhang S.L., Wei J.W., Wang J.B., Pan M.J., Xie Y.L., Yang H.L., Zhou Z., Xie S.H., Wang B.M., Li R.W., Magnetic anisotropy and high-frequency property of flexible FeCoTa films obliquely deposited on a wrinkled topography, Sci. Rep., 7, 1, (2017); You D., Zhang H.T., Ganorkar S., Kim T., Schroers J., Vlassak J.J., Lee D., Electrical resistivity as a descriptor for classification of amorphous versus crystalline phases of alloys, Acta Mater, 231, (2022); Fan X.L., Xue D.S., Lin M., Zhang Z.M., Guo D.W., Jiang C.J., Wei J.Q., In situ fabrication of Co90Nb10 soft magnetic thin films with adjustable resonance frequency from 1.3 to 4.9 GHz, Appl. Phys. Lett., 92, 22, (2008); Han Z.Y., Song C.J., Zhou J., Ma Z., Ma L., Gao H., Zheng F., Influence of the deposition conditions on the magnetic properties of Fe-Co-N thin films, J. Alloys Compd., 934, (2023); Li S.D., Yuan Z.R., Duh J.G., High-frequency ferromagnetic properties of as-deposited FeCoZr films with uniaxial magnetic anisotropy, J. Phys. D: Appl. Phys., 41, 5, (2008); Herzer G., Grain size dependence of coercivity and permeability in nanocrystalline ferromagnets, IEEE Trans. Magn., 26, pp. 1397-1402, (1990); Loffler J.F., Braun H.B., Wagner W., Kostorz G., Wiedenmann A., Crossover in the magnetic properties of nanostructured metals, Mater. Sci. Eng.: A, 304-306, pp. 1050-1054, (2001); Zheng F., Han Z.Y., Li S.T., Ma Z., Gao H., Improvement of soft magnetic properties and in-plane uniaxial magnetic anisotropy in FeCoAlO films fabricated by asymmetric targets, Appl. Phys. A, 128, 4, (2022); Zheng F., Wang X., Li X., Bai J.M., Wei D., Liu X.X., Xie W.H., Wei F.L., High frequency characteristics of FeCoAlO thin films combined the effects of stress and magnetic field, J. Appl. Phys., 109, 7, (2011); Li S.D., Huang Z.G., Duh J., Yamaguchi M., Ultrahigh-frequency ferromagnetic properties of FeCoHf films deposited by gradient sputtering, Appl. Phys. Lett., 92, 9, (2008); Kittel C., Interpretation of anomalous Larmor frequencies in ferromagnetic resonance experiment, Phys. Rev., 71, 4, (1947); Gilbert T.L., Classics in magnetics A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Ge S.H., Yao D.S., Yamaguchi M., Yang X.L., Zuo H., Ishii T., Zhou D., Li F.S., Microstructure and magnetism of FeCo-SiO2 nano-granular films for high frequency application, J. Phys. D: Appl. Phys., 40, 12, (2007); Wang Z.K., Feng E.X., Zhang Y., Liu Q.F., Wang J.B., Optimum electrodeposition conditions of FeCoZr films with in-plane uniaxial anisotropy for high frequency application, Mater. Chem. Phys., 137, 2, pp. 499-502, (2012); Lu G.D., Zhang H.W., Xiao J.Q., Tang X.Q., Zhong Z.Y., Bai F.M., High-frequency properties and thickness-dependent damping factor of FeCo-SiO2 thin films, IEEE Trans. Magn., 48, 11, pp. 3654-3657, (2012); Liu X.L., Wang L.S., Luo Q., Xu L., Yuan B.B., Peng D.L., Preparation and high-frequency soft magnetic property of FeCo-based thin films, Rare Met, 35, 10, pp. 742-746, (2015); Wang Y.C., Zhang H.W., Wang L., Bai F.M., Compositional dependence of magnetic and high frequency properties of nanogranular FeCo-TiO2 films, J. Appl. Phys., 115, 17, (2014); Bai G.H., Jin J.Y., Wu C., Yan M., Microstructure and electromagnetic performance of the FeCoAlON films tuned by N2 pressure during reactive pulsed laser deposition, J. Alloys Compd., 739, pp. 866-872, (2018)","X. Wang; Department of Physics, School of Science, Lanzhou University of Technology, Lanzhou, 730050, China; email: wangxuan2010@lut.edu.cn; F. Zheng; School of Physics, Ningxia University, Yinchuan, 750021, China; email: zhengfu@nxu.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85180758590" +"Yao Y.; Li L.; Wang L.; Sun Z.; Yang G.","Yao, Yuwei (57908119400); Li, Lei (57207133437); Wang, Liqun (57196342040); Sun, Zhengping (58773486800); Yang, Guolai (13408131900)","57908119400; 57207133437; 57196342040; 58773486800; 13408131900","Magneto-mechanical properties of sintered NdFeB under impact load: Impact-induced demagnetization experiment, constitutive model and micromagnetic simulation","2024","Journal of Alloys and Compounds","987","","174134","","","","1","10.1016/j.jallcom.2024.174134","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85188734826&doi=10.1016%2fj.jallcom.2024.174134&partnerID=40&md5=4a21827b85135cee64a028f2d9376470","School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China","Yao Y., School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China; Li L., School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China; Wang L., School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China; Sun Z., School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China; Yang G., School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China","With the widespread applications of sintered NdFeB, the impact-prone scenarios are often encountered. Such impacts will cause magnetic disorder inside the magnet and further demagnetization. At present, research on impact-induced demagnetization of sintered NdFeB mostly focuses on experimental investigations, lacking clear theoretical expressions and visual reproduction of the microscopic demagnetization process. To end this, this paper uses the impact-induced demagnetization experiment, theoretical expression, and micromagnetic simulation to reveal and quantify the demagnetization behavior of NdFeB. An impact-induced demagnetization experimental platform capable of producing corresponding load amplitudes is first established. The experimental results demonstrate the existence of reversible and irreversible demagnetization of NdFeB under impact. A magneto-mechanical constitutive model for sintered NdFeB considering stress history is further developed using the principle of thermodynamic, pinning effect and proximity effect. The residual magnetization intensity between the numerical simulation and the experimental results have good agreement. Finally, the demagnetization behavior of the magnet is visually displayed through the micromagnetic simulation. Employing the LLG equation and kinematic equations for elastic waves, a set of magnetization dynamics equations is established to analyze impact-induced demagnetization characteristics in sintered NdFeB. These results will provide the reference for the application of NdFeB in impact environment. © 2024 Elsevier B.V.","Impact-induced demagnetization experiment; Magneto-mechanical constitutive model; Micromagnetic simulation; Sintered NdFeB","Constitutive models; Demagnetization; Elastic waves; Iron alloys; Magnetic logic devices; Magnetization; Neodymium alloys; Sintering; Demagnetization behaviors; Impact loads; Impact-induced demagnetization experiment; Magnetic disorder; Magneto-mechanical constitutive model; Mechanical; Micromagnetic simulations; Modeling simulation; Sintered NdFeB; Theoretical expression; Magnetos","","","","","Natural Science Foundation of Jiangsu Province, (BK20210342); Natural Science Foundation of Jiangsu Province; China National Postdoctoral Pro-gram for Innovative Talents”, (2023ZB317, 2023ZB318, 52305155, BK20230904, BX20230493); National Natural Science Foundation of China, NSFC, (52105106); National Natural Science Foundation of China, NSFC; China Academy of Space Technology, CAST, (2023JCJQQT061); China Academy of Space Technology, CAST","Funding text 1: This research was financially supported by the “Young Elite Scientists Sponsorship Program by CAST” [Grant No. 2023JCJQQT061], the “National Natural Science Foundation of China” [Grant No. 52105106], the “Jiangsu Province Natural Science Foundation” [Grant No. BK20210342], the “China National Postdoctoral Pro-gram for Innovative Talents” [Grant No. BX20230493], the “National Natural Science Foundation of China” [Grant No. 52305155], the “Jiangsu Province Natural Science Foundation” [Grant No. BK20230904], the “Jiangsu Province Excel-lent Postdoctoral Program” [Grant No. 2023ZB318]. Besides, the authors wish to express their many thanks to the reviewers for their useful and constructive comments. ; Funding text 2: This research was financially supported by the “Young Elite Scientists Sponsorship Program by CAST” [Grant No. 2023JCJQQT061], the “National Natural Science Foundation of China” [Grant No. 52105106], the “Jiangsu Province Natural Science Foundation” [Grant No. BK20210342], the “China National Postdoctoral Pro-gram for Innovative Talents” [Grant No. BX20230493], the “National Natural Science Foundation of China” [Grant No. 52305155], the “Jiangsu Province Natural Science Foundation” [Grant No. BK20230904], the “Jiangsu Province Excel-lent Postdoctoral Program” [Grant No. 2023ZB317]. Besides, the authors wish to express their many thanks to the reviewers for their useful and constructive comments.","Wei C.-F., Et al., The latest development and future application of sintered NdFeB, Rare Met. Cem. Carbides, 38, 1, pp. 47-49, (2010); Shkuratov S.I., Et al., Ultracompact explosive-driven high-current source of primary power based on shock wave demagnetization of Nd2Fe14B hard ferromagnetics, Rev. Sci. Instrum., 73, 7, pp. 2738-2742, (2002); QiaoYan L.I., Et al., Shock Compression Behavior of Nd2Fe14B, Chin. J. High. Press. Phys., 21, 2, pp. 210-214, (2007); Li Z.-X., Et al., Irreversible demagnetization mechanism of permanent magnets during electromagnetic buffering, Def. Technol., 17, 3, pp. 763-774, (2021); Li Z.-X., Et al., Interval uncertain optimization for damping fluctuation of a segmented electromagnetic buffer under intensive impact load, Def. Technol., 17, 3, pp. 884-897, (2021); Mallin L., Barrans S., Comparison of theoretical approaches to determine the stresses in surface mounted permanent magnet rotors for high speed electric machines, J. Strain Anal. Eng. Des., 57, 3, pp. 177-192, (2022); Khan H.A., Et al., Design and performance investigation of 3-slot/2-pole high speed permanent magnet machine, IEEE Access, 9, pp. 41603-41614, (2021); Gao P., Et al., Mechanical strength analysis and optimization of metallic sleeve in high-speed permanent magnet synchronous machines, Int. J. Appl. Electromagn. Mech., 63, 2, pp. 343-359, (2020); Li L., Et al., Experimental and theoretical model study on the dynamic mechanical behavior of sintered NdFeB, J. Alloy. Compd., 890, (2022); Zhang P., Jin K., Zheng X., Magneto-mechanical coupling model of ferromagnetic materials under fatigue loading and its application in metal magnetic memory method, J. Magn. Magn. Mater., 514, (2020); Kim S., Et al., A nonlinear magneto-mechanical coupling model for magnetization and magnetostriction of ferromagnetic materials, AIP Adv., 10, 8, (2020); Shi P., Jin K., Zheng X., A magnetomechanical model for the magnetic memory method, Int. J. Mech. Sci., 124, pp. 229-241, (2017); Shi P., Magneto-elastoplastic coupling model of ferromagnetic material with plastic deformation under applied stress and magnetic fields, J. Magn. Magn. Mater., 512, (2020); Porter D.G., Et al., Irregular grain structure in micromagnetic simulation, J. Appl. Phys., 79, 8, pp. 4695-4697, (1996); Bao L., Et al., Grain-size effect on coercivity of Nd–Fe–B nanomagnets: micromagnetics simulation based on a multi-grain model, Appl. Phys. Express, 14, 8, (2021); Sun Z., Et al., Micromagnetic simulation of Nd-Fe-B demagnetization behavior in complex environments, J. Magn. Magn. Mater., (2023); Bauer F., Lichtenberger A., Use of PVF2 shock gauges for stress measurements in Hopkinson bar, Shock Waves Condens. Matter, pp. 631-634, (1987); Xi D., Zheng Y., Application of PVDF gauges to dynamical stress measurements, Explos. Shock Waves, 15, 2, pp. 174-179, (1995); Meng Y., Yi W., Application of a PVDF-based stress gauge in determining dynamic stress–strain curves of concrete under impact testing, Smart Mater. Struct., 20, 6, (2011); Li Y., Et al., Response of homemade PVDF piezofilm under shock loading and unloading, Chin. J. High. Press. Phys., 18, 3, pp. 261-266, (2004); Shi P., Jin K., Zheng X., A general nonlinear magnetomechanical model for ferromagnetic materials under a constant weak magnetic field, J. Appl. Phys., 119, 14, (2016); Kuruzar M.E., Cullity B., The magnetostriction of iron under tensile and compressive stress, Int. J. Magn., 1, 4, pp. 323-325, (1971); Jiles D., Theory of the magnetomechanical effect, J. Phys. D: Appl. Phys., 28, 8, (1995); Sagawa M., Et al., New material for permanent magnets on a base of Nd and Fe, J. Appl. Phys., 55, 6, pp. 2083-2087, (1984); Bao L., Et al., Micromagnetics of Nd–Fe–B magnets at finite temperature, Jpn. J. Appl. Phys., 60, 3, (2021); Zhou H.-M., Et al., A general 3-D nonlinear magnetostrictive constitutive model for soft ferromagnetic materials, J. Magn. Magn. Mater., 321, 4, pp. 281-290, (2009); Zhou H.-M., Zhou Y.-H., Zheng X.-J., A general theoretical model of magnetostrictive constitutive relationships for soft ferromagnetic material rods, J. Appl. Phys., 104, 2, (2008); Jiles D.C., Atherton D.L., Theory of ferromagnetic hysteresis, J. Magn. Magn. Mater., 61, 1-2, pp. 48-60, (1986); Jiles D.C., Thoelke J., Devine M., Numerical determination of hysteresis parameters for the modeling of magnetic properties using the theory of ferromagnetic hysteresis, IEEE Trans. Magn., 28, 1, pp. 27-35, (1992); Lakshmanan M., The fascinating world of the Landau–Lifshitz–Gilbert equation: an overview, Philos. Trans. R. Soc. A Math. Phys. Eng. Sci., 369, 1939, pp. 1280-1300, (2011); Zhang J., Et al., A frequency-domain micromagnetic simulation module based on COMSOL Multiphysics, AIP Adv., 13, 5, (2023); Navier C.-L., Navier Stokes Equation, (1838); Sun Z., Et al., Micromagnetic simulation of Nd-Fe-B demagnetization behavior in complex environments, J. Magn. Magn. Mater., (2023); Kim S.-K., Hwang S., Lee J.-H., Effect of misalignments of individual grains’ easy axis on magnetization-reversal process in granular NdFeB magnets: a finite-element micromagnetic simulation study, J. Magn. Magn. Mater., 486, (2019); Lu F., Xu S., Wang L.-H., Pressure-induced magnetic transition in Nd 2 Fe 14 B based on two-sublattice model, Rare Met., 41, pp. 232-239, (2022); Li L., Et al., Dynamic magnetomechanical behavior of sintered Nd2Fe14B under impact, J. Alloy. Compd., 936, (2023)","L. Li; School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China; email: lilei@njust.edu.cn","","Elsevier Ltd","","","","","","09258388","","JALCE","","English","J Alloys Compd","Article","Final","","Scopus","2-s2.0-85188734826" +"Yari P.; Chugh V.K.; Saha R.; Tonini D.; Rezaei B.; Mostufa S.; Xu K.; Wang J.-P.; Wu K.","Yari, Parsa (58142212100); Chugh, Vinit Kumar (57192919522); Saha, Renata (57208154558); Tonini, Denis (57412731300); Rezaei, Bahareh (58250289300); Mostufa, Shahriar (57226573979); Xu, Kanglin (58519374900); Wang, Jian-Ping (35782368600); Wu, Kai (56095374500)","58142212100; 57192919522; 57208154558; 57412731300; 58250289300; 57226573979; 58519374900; 35782368600; 56095374500","Static and dynamic magnetization models of magnetic nanoparticles: an appraisal","2023","Physica Scripta","98","8","082002","","","","6","10.1088/1402-4896/ace8d1","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85166465243&doi=10.1088%2f1402-4896%2face8d1&partnerID=40&md5=e114bc36490754e2d5370bf4669e68c2","Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States; Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Department of Computer Science, Texas Tech University, Lubbock, 79409, TX, United States","Yari P., Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States; Chugh V.K., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Saha R., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Tonini D., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Rezaei B., Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States; Mostufa S., Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States; Xu K., Department of Computer Science, Texas Tech University, Lubbock, 79409, TX, United States; Wang J.-P., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Wu K., Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States","Nowadays, magnetic nanoparticles (MNPs) have been extensively used in biomedical fields such as labels for magnetic biosensors, contrast agents in magnetic imaging, carriers for drug/gene delivery, and heating sources for hyperthermia, among others. They are also utilized in various industries, including data and energy storage and heterogeneous catalysis. Each application exploits one or more physicochemical properties of MNPs, including magnetic moments, magnetophoretic forces, nonlinear dynamic magnetic responses, magnetic hysteresis loops, and others. It is generally accepted that the static and dynamic magnetizations of MNPs can vary due to factors such as material composition, crystal structure, defects, size, shape of the MNP, as well as external conditions like the applied magnetic fields, temperature, carrier fluid, and inter-particle interactions (i.e., MNP concentrations). A subtle change in any of these factors leads to different magnetization responses. In order to optimize the MNP design and external conditions for the best performance in different applications, researchers have been striving to model the macroscopic properties of individual MNPs and MNP ensembles. In this review, we summarize several popular mathematical models that have been used to describe, explain, and predict the static and dynamic magnetization responses of MNPs. These models encompass both individual MNPs and MNP ensembles and include the Stoner-Wohlfarth model, Langevin model, zero/non-zero field Brownian and Néel relaxation models, Debye model, empirical Brownian and Néel relaxation models under AC fields, the Landau-Lifshitz-Gilbert (LLG) equation, and the stochastic Langevin equation for coupled Brownian and Néel relaxations, as well as the Fokker-Planck equations for coupled/decoupled Brownian and Néel relaxations. In addition, we provide our peers with the advantages, disadvantages, as well as suitable conditions for each model introduced in this review. The shrinking size of magnetic materials brings about a significant surface spin canting effect, resulting in higher anisotropy and lower magnetization in MNPs compared to bulk materials. Accurate prediction of static and dynamic magnetizations in MNPs Requires both precise data on their magnetic properties and an accurate mathematical model. Hence, we introduced the spin canting effect and models to estimate anisotropy and saturation magnetization in MNPs. © 2023 IOP Publishing Ltd.","dynamic magnetic response; magnetic biosensor; magnetic imaging; magnetic nanoparticle; mathematic model; static magnetic response","Biosensors; Brownian movement; Crystal structure; Digital storage; Fokker Planck equation; Magnetic materials; Magnetic moments; Nanomagnetics; Physicochemical properties; Saturation magnetization; Stochastic models; Brownian relaxations; Dynamic magnetic response; Magnetic biosensors; Magnetic imaging; Magnetic response; Mathematics model; Static magnetic response; Static magnetization; Statics and dynamics; Stochastic systems","","","","","NRUF; Texas Tech University, TTU; University of Minnesota, UMN; Minnesota Supercomputing Institute, University of Minnesota, MSI","Funding text 1: This study was financially supported by the Texas Tech University through HEF New Faculty Startup, NRUF Start Up and Core Research Support Fund. The authors acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported in this publication. B R acknowledges the Distinguished Graduate Student Assistantships (DGSA) offered by Texas Tech University. V K C acknowledges the Interdisciplinary Doctoral Fellowship (IDF) offered by University of Minnesota. ; Funding text 2: This study was financially supported by the Texas Tech University through HEF New Faculty Startup, NRUF Start Up and Core Research Support Fund. The authors acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported in this publication. B R acknowledges the Distinguished Graduate Student Assistantships (DGSA) offered by Texas Tech University. V K C acknowledges the Interdisciplinary Doctoral Fellowship (IDF) offered by University of Minnesota.","Alonso J, Barandiaran J M, Barquin L F, Garcia-Arribas A, Magnetic nanoparticles, synthesis, properties, and applications Magnetic nanostructured materials El-Gendy Ahmed A, (2018); Wu K, Su D, Liu J, Saha R, Wang J-P, Magnetic nanoparticles in nanomedicine: a review of recent advances, Nanotechnology, 30, (2019); Singamaneni S, Bliznyuk V N, Binek C, Tsymbal E Y, Magnetic nanoparticles: recent advances in synthesis, self-assembly and applications, J. Mater. Chem, 21, pp. 16819-1684516819, (2011); Krishnan K M, Pakhomov A B, Bao Y, Blomqvist P, Chun Y, Gonzales M, Griffin K, Ji X, Roberts B K, Nanomagnetism and spin electronics: materials, microstructure and novel properties, J. Mater. Sci, 41, pp. 793-815793, (2006); Jonsson P E, Garcia-Palacios J L, Thermodynamic perturbation theory for dipolar superparamagnets, Phys. Rev. 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Mater, 563, (2022); Zhong J, Rosch E L, Viereck T, Schilling M, Ludwig F, Toward rapid and sensitive detection of SARS-CoV-2 with functionalized magnetic nanoparticles, ACS Sens, 6, pp. 976-984976, (2021); Wu K, Liu J, Su D, Saha R, Wang J-P, Magnetic nanoparticle relaxation dynamics-based magnetic particle spectroscopy for rapid and wash-free molecular sensing, ACS Appl. Mater. Interfaces, 11, (2019)","K. Wu; Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, United States; email: kai.wu@ttu.edu","","Institute of Physics","","","","","","00318949","","PHSTB","","English","Phys Scr","Review","Final","","Scopus","2-s2.0-85166465243" +"Denny B.; Garrett T.; Schrock J.","Denny, Bud (57226174446); Garrett, Travis (56478498700); Schrock, James (55942783600)","57226174446; 56478498700; 55942783600","Full-Wave FDTD Modeling and Simulation of Nonlinear Transmission Lines","2023","IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)","2023-July","","","1431","1432","1","1","10.1109/USNC-URSI52151.2023.10237742","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85172415978&doi=10.1109%2fUSNC-URSI52151.2023.10237742&partnerID=40&md5=baab120349e65d1ec2eeb919f7f5e34c","Directed Energy, Air Force Research Laboratory, 87117, NM, United States","Denny B., Directed Energy, Air Force Research Laboratory, 87117, NM, United States; Garrett T., Directed Energy, Air Force Research Laboratory, 87117, NM, United States; Schrock J., Directed Energy, Air Force Research Laboratory, 87117, NM, United States","We present a numerical scheme for simulating a ferrite loaded nonlinear transmission line (NLTL). The numerical scheme is an extension of the well known finite-difference time-domain (FDTD) method. The method couples Maxwell's equations with the nonlinear Landau-Lifshitz-Gilbert (LLG) equation for modeling the dynamics of ferrite material. Furthermore, the method discretizes the domain using the staggered Veegrid with the magnetization vectors (M-fields) located at cell centers; the usual FDTD electric field and magnetic field updates are unchanged. We then validate the method and model by comparing simulation results with an Air Force Research Laboratory (AFRL) high-power NLTL experiment. © 2023 IEEE.","","Electric fields; Electric lines; Electric power transmission; Ferrite; Finite difference time domain method; Nonlinear equations; Numerical methods; Research laboratories; Cell centers; Ferrite materials; Finite-difference time-domain modeling; Finite-difference time-domain simulation; Full waves; Landau-Lifshitz-Gilbert equations; Magnetization vector; Model and simulation; Nonlinear transmission lines; Numerical scheme; Maxwell equations","","","","","","","French D.M., Hoff B.W., Spatially dispersive ferrite nonlinear transmission line with axial bias, IEEE Transactions on Plasma Science, 42, 10, pp. 3387-3390, (2014); Dolan J.E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, Journal of Physics D: Applied Physics, 32, 15, pp. 1826-1831, (1999); Peterkin R.E., Luginsland J.W., A virtual prototyping environment for directed-energy concepts, Computing in Science Engineering, 4, 2, pp. 42-49, (2002); Taflove A., Introduction to maxwell's equations and the yee algorithm, Computational Electrodynamics: The Finite-Difference Time-Domain Method, pp. 51-501, (2005); Pereda J., Vielva L., Vegas A., Prieto A., A treatment of magnetized ferrites using the fdtd method, IEEE Microwave and Guided Wave Letters, 3, 5, pp. 136-138, (1993); Aziz M.M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, (2009); Xiao T., Liu Q.H., A 3-d enlarged cell technique (ect) for the conformal fdtd method, IEEE Transactions on Antennas and Propagation, 56, 3, pp. 765-773, (2008)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (AP-S); The Institute of Electrical and Electronics Engineers (IEEE); US National Committee (USNC) for the International Union of Radio Science (URSI)","2023 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2023","23 July 2023 through 28 July 2023","Portland","192525","15223965","978-166544228-2","IAPSB","","English","IEEE Antennas Propag Soc AP S Int Symp","Conference paper","Final","","Scopus","2-s2.0-85172415978" +"Maloberti O.","Maloberti, Olivier (9735831500)","9735831500","Entanglement between Micro-Magnetism, electromagnetism and the Tensor Magnetic Phase Theory (TMPT) – Symmetry, conservation and invariance laws analysis at low frequency","2024","Results in Physics","62","","107727","","","","0","10.1016/j.rinp.2024.107727","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85196491895&doi=10.1016%2fj.rinp.2024.107727&partnerID=40&md5=6df56ba3b05fca2814c6aa0052c0b7a3","UniLaSalle Amiens, 14 Quai de La Somme, Amiens, 80080, France","Maloberti O., UniLaSalle Amiens, 14 Quai de La Somme, Amiens, 80080, France","Ferromagnetic materials show magnetic structures with domains and walls. Thanks to decades of research regarding the origin and behaviour of magnetic domains, we now possess a general foundation which has been verified experimentally in single crystals and powders. The governing equations at the microscopic scale were built in the 1960 s when Brown published calculations of the magnetic moments distribution inside domain walls. This micromagnetic theory uses the so called LLG ‘Landau-Lifshitz-Gilbert’ equation and can include the damping effects. The LLG equation requires a coupling to the field derived from energy contributions: exchange, anisotropy, magnetostriction, stray-field … and the anti-eddy field. At the macroscopic scale, such behaviours are lumped in a homogenized magnetization law for the electromagnetic field equations inside larger polycrystals. Therefore, the inhomogeneous magnetic material nature is always ignored. The Tensor Magnetic Phase Theory (TMPT) describes the magnetic structure and the magnetization thanks to a tensor variable at a mesoscopic scale. The material structuring is then explained thanks to an energy balance which will be discussed. This paper presents the results of investigations on entangled relationships between the micromagnetic theory, the electromagnetic theory and what is called the Tensor Magnetic Phase Theory (TMPT), which statistically describes the magnetic structures of soft ferromagnetic materials. It examines a connection between the TMPT and the LLG by deriving the main energy terms. Then, the TMPT must stay compatible and coupled to the Maxwell equations at low frequencies with volume and surface connections. Additionally, this paper investigates the way to derive the domains structuring and magnetization laws through the Lagrange principle and the corresponding conservation laws with invariants linked to the Nœther theorem. Finally, the TMPT must be discussed while checking its coherence and formulation when changing the reference frame. © 2024 The Author","Action minimization principle; CPT symmetries; Domains structure; Electromagnetism at low frequencies; Euler-Lagrange equations; Ferroelectric materials; Ferromagnetic materials; Homogenization; Invariance principle; Lagrangian; Maxwell equations; Micro-magnetism; Multiferroic materials; Nœther theorem; Polarizable media; Polarized domains; Poynting theorem; Tensor Magnetic Phase Theory; Walls; ‘Landau-Lifshitz-Gilbert’ equation","","","","","","European Commission, EC; Horizon 2020, (766437); Horizon 2020","Funding text 1: We thank the European Commission (EC) for financial support to this work ( Grant No. 766437 ). ; Funding text 2: We thank the European Union's Horizon 2020 research and innovation program for the partial financial support to this work under the grant agreement No. 766437.","Bitter F., On Inhomogeneities in the Magnetization of Ferromagnetic Materials, Phys Rev, 38, pp. 1903-1905, (1931); Bloch F., Zur Theorie des Ferromagnetismus, Z Phys, 61, pp. 206-219, (1930); Hubert A., Schafer R., Magnetic Domains ” (springer, (2000); Ashcroft N.W., Mermin N.D., Physique des solides, (2002); Brailsford, ”Physical principles of magnetism” (London, D, Von Nostrand Company LTD, (1966); Chikasumi S., Physics of Ferromagnetism, (1997); Brown W.F., Criteria for uniform micromagnetization, Phys Rev, 105, 5, pp. 1479-1482, (1957); Brown W.F., Micromagnetics: Domain walls / Micromagnetics, Domains and resonance, J Appl Phys, 30, 4, pp. 625-695, (1959); Gilbert T.L., A Lagrangian of the gyromagnetic equation of the magnetization field, Phys Rev, 100, (1955); Neel L., Les lois de l'aimantation et de la subdivision en domaines élémentaires d'un monocristal de Fer, Journal de Physique et le Radium, Tome 5, série 8, 11, pp. 241-251, (1944); Williams H., Shockley W., Kitte C., Studies of the propagation velocity of a ferromagnetic domain boundary, Phys Rev, 80, 6, pp. 1090-1094, (1950); Pry R.H., Bean C.P., Calculation of the Energy Loss in Magnetic Sheet Materials Using a Domain Model, J Appl Phys, 29, 3, pp. 532-533, (1958); Bishop J.E.L., Magnetic domain structure, eddy currents and permeability spectra, Br J Appl Phys, 17, pp. 1451-1459, (1966); Chen D.X., Munoz J.L., Theoretical eddy current permeability spectra of slabs with bar domains, IEEE Trans Magn, 33, 3, pp. 2229-2244, (1997); Landau L.D., Lifchitz E.M., ”physique Statistique” (edition De Moscou, (1984); Bertotti G., Hysteresis in magnetism, (1998); Landau L.D., Lifchitz E.M., Electrodynamique des milieux continus, (edition De Moscou, (1984); Landau L., Et al., On the theory of dispersion of magnetic permeability in ferromagnetic bodies, Physikalische Zeitschrift Der Sowjetunion, 8, pp. 153-169, (1935); Lifshitz E., On the magnetic structure of iron, J Phys ussr, 8, pp. 337-346, (1944); Kittel C., Physical Theory of Ferromagnetic Domains”, Review of modern physics, 21, 4, (1949); Brown W.F., Micromagnetics, (1963); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans Magn, 40, 6, pp. 3443-3449, (2004); Maxwell J.; Joseph Larmor, “A dynamical theory of the electric and luminiferous medium.— Part III. relations with material media”, Philosophical Transactions of the Royal Society of London, Series a, Containing Papers of a Mathematical or Physical Character, 190, pp. 205-230, (1897); Kittel C., Larmor and the Prehistory of the Lorentz Transformation, Am J Phys, 42, pp. 726-729, (1971); Maloberti O., Et al., An Energy-Based Formulation for Dynamic Hysteresis and Extra-Losses, IEEE Trans Magn, 42, 4, pp. 895-898, (2006); Maloberti O., Et al., The tensor magnetic phase theory for mesoscopic volume structures of soft magnetic materials – Quasi-static and dynamic vector polarization, apparent permeability and losses – Experimental identifications of GO steel at low induction levels, J Magn Magn Mater, 502, (2020); Russakoff G., A derivation of the macroscopic Maxwell equations, Am J Phys, 38, 10, pp. 1188-1195, (1970); Gratiy S.L., Et al.; Serret M.J.-A.; Noether E., Invariante Variationsprobleme, Nachrichten Von Der Gesellschaft Der Wissenschaften Zu Göttingen, Mathematisch-Physikalische Klasse 1918, 2, pp. 235-267, (1918); Christophe Eckes, Principes d'invariance et lois de la nature d'après Weyl et Wigner, Philosophia Scientiæ, 16-3, (2012); Wigner E.P., The Role of Invariance Principles in Natural Philosophy, (1979); Bell J.S., (1954); Hendryk Antoon Lorentz, Minkowski H., Weyl H., Das relativitätsprinzip, (1922); Poincare H., 9, pp. 464-488, (1900); Einstein A., Elektrodynamik bewegter Körper, Annalen der Physik, no. 4, pp. 891-921, (1905); Franklin J.; Felix Klein, Über die geometrischen Grundlagen der Lorentzgruppe, Jahresber Deutsch Math-Verein, 19, pp. 281-300, (1910); Maloberti O., Salloum E., Ababsa M.L., Nesser M., Panier S., Dassonvalle P., Fortin J., Pineau C., Birat J.-P., Sheet thickness dependence of magnetization properties based on domains and walls within the non-linear diffusion-like equation for grain-oriented electrical steels, J Magn Magn Mater, 557, (2022); Maloberti O., Meunier G., Kedous-Lebouc A., Mazauric V., (2007); Maloberti O., Kedous-Lebouc A., Meunier G., Mazauric V., (2007); Maloberti O., Nesser M., Dupuy J., Dassonvalle P., Fortin J., Pineau C., Birat J.P., Discriminating the physical impacts of various laser pulses on the magnetic structure of oriented electrical steels, J Magn Magn Mater, 566, (2023); Maloberti O., Nesser M., Salloum E., Dupuy J., Dassonvalle P., Pineau C., Panier S., Birat J.P., Relative control of domains’ structure in Grain-Oriented electrical steels by Ultra-Short Pulsed laser ablation process, J Magn Magn Mater, 580, (2023); Bruckner F., Et al., Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations, J Magn Magn Mater, 343, pp. 163-168, (2013)","","","Elsevier B.V.","","","","","","22113797","","","","English","Results Phys.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85196491895" +"Assouline B.; Capua A.","Assouline, Benjamin (55504596500); Capua, Amir (16300540000)","55504596500; 16300540000","Helicity-dependent optical control of the magnetization state emerging from the Landau-Lifshitz-Gilbert equation","2024","Physical Review Research","6","1","013012","","","","1","10.1103/PhysRevResearch.6.013012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183584617&doi=10.1103%2fPhysRevResearch.6.013012&partnerID=40&md5=d11e7a522ef9e95ee80b32b6927d0041","Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel","Assouline B., Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel; Capua A., Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel","It is well known that the Gilbert relaxation time of a magnetic moment scales inversely with the magnitude of the externally applied field, H, and the Gilbert damping, α. Therefore, in ultrashort optical pulses, where H can temporarily reach high amplitudes, the Gilbert relaxation time can momentarily be extremely short, reaching even picosecond timescales. Here we show that for strong enough ultrashort pulses, the magnetization can respond within the optical cycle such that the optical control of the magnetization emerges by merely considering the optical magnetic field in the Landau-Lifshitz-Gilbert (LLG) equation. Surprisingly, when circularly polarized optical pulses are introduced, an optically induced helicity-dependent torque results. We find that the strength of the interaction is determined by η=αγH/fopt, where fopt and γ are the optical frequency and gyromagnetic ratio, respectively. Our results illustrate the generality of the LLG equation to the optical limit and the pivotal role of the Gilbert damping in the general interaction between optical magnetic fields and spins in solids. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.","","Damping; Laser pulses; Magnetic fields; Magnetic moments; Magnetization; Applied field; Gilbert damping; Helicities; High amplitudes; Landau-Lifshitz-Gilbert equations; Magnetization state; Optical control; Optical magnetic fields; Picoseconds; Ultra short optical pulse; Relaxation time","","","","","Center for Nanoscience and Nanotechnology of the Hebrew University of Jerusalem; Peter Brojde Center for Innovative Engineering and Computer Science; Israel Science Foundation, ISF, (1217/21)","A.C. and B.A. acknowledge the support from the Israel Science Foundation (Grant No. 1217/21), the Peter Brojde Center for Innovative Engineering and Computer Science, and from the Center for Nanoscience and Nanotechnology of the Hebrew University of Jerusalem.","Stanciu C. D., Hansteen F., Kimel A. V., Kirilyuk A., Tsukamoto A., Itoh A., Rasing T., All-optical magnetic recording with circularly polarized light, Phys. Rev. Lett, 99, (2007); Vahaplar K., Kalashnikova A. M., Kimel A. V., Gerlach S., Hinzke D., Nowak U., Chantrell R., Tsukamoto A., Itoh A., Kirilyuk A., Rasing T., All-optical magnetization reversal by circularly polarized laser pulses: Experiment and multiscale modeling, Phys. Rev. B, 85, (2012); Hassdenteufel A., Hebler B., Schubert C., Liebig A., Teich M., Helm M., Aeschlimann M., Albrecht M., Bratschitsch R., Thermally assisted all-optical helicity dependent magnetic switching in amorphous (Equation presented) alloy films, Adv. Mater, 25, (2013); Alebrand S., Gottwald M., Hehn M., Steil D., Cinchetti M., Lacour D., Fullerton E. E., Aeschlimann M., Mangin S., Light-induced magnetization reversal of high-anisotropy TbCo alloy films, Appl. Phys. Lett, 101, (2012); Mangin S., Gottwald M., Lambert C. 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Phys, 82, (2010); Kichin G., Hehn M., Gorchon J., Malinowski G., Hohlfeld J., Mangin S., From multiple-to single-pulse all-optical helicity-dependent switching in ferromagnetic Co/Pt multilayers, Phys. Rev. Appl, 12, (2019); Choi G.-M., Schleife A., Cahill D. G., Optical-helicity-driven magnetization dynamics in metallic ferromagnets, Nat. Commun, 8, (2017); Nemec P., Rozkotova E., Tesarova N., Trojanek F., De Ranieri E., Olejnik K., Zemen J., Novak V., Cukr M., Maly P., Jungwirth T., Experimental observation of the optical spin transfer torque, Nat. Phys, 8, (2012); Freimuth F., Blugel S., Mokrousov Y., Laser-induced torques in metallic ferromagnets, Phys. Rev. B, 94, (2016); Zhang G. P., Latta T., Babyak Z., Bai Y. H., George T. F., All-optical spin switching: A new frontier in femtomagnetism-A short review and a simple theory, Mod. Phys. Lett. B, 30, (2016); Zhang P., Chung T.-F., Li Q., Wang S., Wang Q., Huey W. L. B., Yang S., Goldberger J. 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H., Petit-Watelot S., Quessab Y., Hehn M., Montaigne F., Malinowski G., Mangin S., Two types of all-optical magnetization switching mechanisms using femtosecond laser pulses, Phys. Rev. B, 94, (2016); Ostler T. A., Barker J., Evans R. F. L., Chantrell R. W., Atxitia U., Chubykalo-Fesenko O., El Moussaoui S., Le Guyader L., Mengotti E., Heyderman L. J., Nolting F., Tsukamoto A., Itoh A., Afanasiev D., Ivanov B. A., Kalashnikova A. M., Vahaplar K., Mentink J., Kirilyuk A., Rasing T., Kimel A. V., Ultrafast heating as a sufficient stimulus for magnetization reversal in a ferrimagnet, Nat. Commun, 3, (2012); Yao J., Agrawal G. P., Gallion P., Bowden C. M., Semiconductor laser dynamics beyond the rate-equation approximation, Opt. Commun, 119, (1995); Capua A., Karni O., Eisenstein G., A finite-difference time-domain model for quantum-dot lasers and amplifiers in the Maxwell and Schrödinger framework, IEEE J. Sel. Top. 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S., Gilbert damping of high anisotropy Co/Pt multilayers, J. Phys. D Appl. Phys, 51, (2018)","","","American Physical Society","","","","","","26431564","","","","English","Phys. Rev. Res.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85183584617" +"d'Aquino M.; Perna S.; Serpico C.","d'Aquino, M. (9732823500); Perna, S. (56439259300); Serpico, C. (23013514800)","9732823500; 56439259300; 23013514800","Midpoint geometric integrators for inertial magnetization dynamics","2024","Journal of Computational Physics","504","","112874","","","","1","10.1016/j.jcp.2024.112874","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85186271596&doi=10.1016%2fj.jcp.2024.112874&partnerID=40&md5=280086b24d04158638005ba7e93bf1e2","Department of Electrical Engineering and Information Technology, University of Naples Federico II, Via Claudio 21, Naples, I-80125, Italy","d'Aquino M., Department of Electrical Engineering and Information Technology, University of Naples Federico II, Via Claudio 21, Naples, I-80125, Italy; Perna S., Department of Electrical Engineering and Information Technology, University of Naples Federico II, Via Claudio 21, Naples, I-80125, Italy; Serpico C., Department of Electrical Engineering and Information Technology, University of Naples Federico II, Via Claudio 21, Naples, I-80125, Italy","We consider the numerical solution of the inertial version of Landau-Lifshitz-Gilbert equation (iLLG), which describes high-frequency nutation on top of magnetization precession due to angular momentum relaxation. The iLLG equation defines a higher-order nonlinear dynamical system with very different nature compared to the classical LLG equation, requiring twice as many degrees of freedom for space-time discretization. It exhibits essential conservation properties, namely magnetization amplitude preservation, magnetization projection conservation, and a balance equation for generalized free energy, leading to a Lyapunov structure (i.e. the free energy is a decreasing function of time) when the external magnetic field is constant in time. We propose two second-order numerical schemes for integrating the iLLG dynamics over time, both based on implicit midpoint rule. The first scheme unconditionally preserves all the conservation properties, making it the preferred choice for simulating inertial magnetization dynamics. However, it implies doubling the number of unknowns, necessitating significant changes in numerical micromagnetic codes and increasing computational costs especially for spatially inhomogeneous dynamics simulations. To address this issue, we present a second time-stepping method that retains the same computational cost as the implicit midpoint rule for classical LLG dynamics while unconditionally preserving magnetization amplitude and projection. Special quasi-Newton techniques are developed for solving the nonlinear system of equations required at each time step due to the implicit nature of both time-steppings. The numerical schemes are validated on analytical solution for macrospin terahertz frequency response and the effectiveness of the second scheme is demonstrated with full micromagnetic simulation of inertial spin waves propagation in a magnetic thin-film. © 2024 The Author(s)","Implicit midpoint rule; Inertial Landau-Lifshitz-Gilbert (iLLG) equation; Magnetic inertia; Micromagnetic simulations; Numerical methods; Terahertz spin nutation","Degrees of freedom (mechanics); Dynamical systems; Dynamics; Free energy; Frequency response; Magnetization; Nonlinear equations; Spin dynamics; Conservation properties; Implicit midpoint rule; Inertial landau-lifshitz-gilbert equation; Landau-Lifshitz-Gilbert equations; Magnetic inertia; Magnetization dynamics; Micromagnetic simulations; Numerical scheme; Tera Hertz; Terahertz spin nutation; Numerical methods","","","","","Ministero dell’Istruzione, dell’Università e della Ricerca, MIUR, (2020PY8KTC); Ministero dell’Istruzione, dell’Università e della Ricerca, MIUR","M.d'A., S.P. and C.S. acknowledge support from the Italian Ministry of University and Research , PRIN2020 funding program, grant number 2020PY8KTC .","Dieny B., Prejbeanu I.L., Garello K., Gambardella P., Freitas P., Lehndorff R., Raberg W., Ebels U., Demokritov S.O., Akerman J., Deac A., Pirro P., Adelmann C., Anane A., Chumak A.V., Hirohata A., Mangin S., Valenzuela S.O., Onbasli M.C., d'Aquino M., Prenat G., Finocchio G., Lopez-Diaz L., Chantrell R., Chubykalo-Fesenko O., Bortolotti P., Opportunities and challenges for spintronics in the microelectronics industry, Nat. Electron., 3, 8, pp. 446-459, (2020); Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Ultrafast spin dynamics in ferromagnetic nickel, Phys. Rev. Lett., 76, 22, pp. 4250-4253, (1996); Koopmans B., van Kampen M., Kohlhepp J.T., de Jonge W.J.M., Ultrafast magneto-optics in nickel: magnetism or optics?, Phys. Rev. Lett., 85, 4, pp. 844-847, (2000); Stamm C., Kachel T., Pontius N., Mitzner R., Quast T., Holldack K., Khan S., Lupulescu C., Aziz E.F., Wietstruk M., Durr H.A., Eberhardt W., Femtosecond modification of electron localization and transfer of angular momentum in nickel, Nat. Mater., 6, 10, pp. 740-743, (2007); Stanciu C.D., Hansteen F., Kimel A.V., Kirilyuk A., Tsukamoto A., Itoh A., Rasing T., All-optical magnetic recording with circularly polarized light, Phys. Rev. Lett., 99, 4, (2007); Kimel A.V., Ivanov B.A., Pisarev R.V., Usachev P.A., Kirilyuk A., Rasing T., Inertia-driven spin switching in antiferromagnets, Nat. 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Comput., 18, 1, pp. 1-22, (1997); d'Aquino M., Magnetization Geometrical Integration Code (MaGICo)","M. d'Aquino; Department of Electrical Engineering and Information Technology, University of Naples Federico II, Naples, Via Claudio 21, I-80125, Italy; email: mdaquino@unina.it","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85186271596" +"Goncharov A.V.","Goncharov, Alexander V. (56394838800)","56394838800","Advanced Micromagnetic Modeling of Recording Heads","2023","IEEE Transactions on Magnetics","59","9","7200210","","","","1","10.1109/TMAG.2023.3299888","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85166327638&doi=10.1109%2fTMAG.2023.3299888&partnerID=40&md5=3f96abb3722437bb026a4b0e7eaa4d1d","Western Digital Corporation, San Jose, 95119, CA, United States","Goncharov A.V., Western Digital Corporation, San Jose, 95119, CA, United States","An efficient algorithm is reported for the micromagnetic modeling of large-scale magnetic objects, such as magnetic recording heads. The numerical scheme for the solution of the Landau-Lifshitz-Gilbert (LLG) equation is a combination of the finite difference (FD), the finite element (FEM), and the fast Fourier transform (FFT) methods. The discretization of differential equation describing the magnetic body and surrounding non-magnetic domain is achieved by applying Galerkin technique. FFT is used for the calculation of boundary conditions for the magnetostatic problem. The derivation of the discrete linear operators for the fast calculation of the magnetic scalar and vector potentials is presented. Explicit integral expression for the total effective magnetic charge in the magnetic domain with non-uniform magnetization of saturation is derived. The numerical approach used in the micromagnetic software allows fast simulations of multi-scale models of recording heads on graphic processing units (GPUs) for modern recording technologies. The examples of simulations of the noise reduction in the energy assisted perpendicular magnetic recording (ePMR) head and exchange biased magnetic shield are presented. © 1965-2012 IEEE.","energy assisted perpendicular magnetic recording (ePMR); magnetic recording; micromagnetics; microwave assisted magnetic recording (MAMR)","Finite element method; Magnetic anisotropy; Magnetic domains; Magnetic heads; Magnetic recording; Magnetic shielding; Magnetostatics; Noise abatement; Numerical methods; Program processors; Saturation magnetization; EPMR; Finite element analyse; Large-scales; Magnetic recording heads; MAMR; Micromagnetic models; Micromagnetics; Perpendicular magnetic anisotropy; Recording head; Boundary conditions","","","","","","","Cooley J.W., Tukey J.W., An algorithm for the machine calculation of complex Fourier series, Math. Comput, 19, 90, pp. 297-301, (1965); Miltat J.E., Donahue M.J., Numerical micromagnetics: Finite difference methods, Handbook of Magnetism and Advanced Magnetic Materials, (2007); Schrefl T., Hrkac G., Bance S., Suess D., Ertl O., Fidler J., Numerical Methods in Micromagnetics (Finite Element Method), (2007); Brunotte X., Meunier G., Imhoff J.F., Finite element modeling of unbounded problems using transformations: A rigorous, powerful and easy solution, IEEE Trans. Magn, 28, 2, pp. 1663-1666, (1992); Forster H., Schrefl T., Dittrich R., Scholz W., Fidler J., Fast boundary methods for magnetostatic interactions in micromagnetics, IEEE Trans. Magn, 39, 5, pp. 2513-2515, (2003); Rokhlin V., Rapid solution of integral equations of classical potential theory, J. Comput. Phys, 60, 2, pp. 187-207, (1985); Phillips J.R., White J.K., A precorrected-FFT method for electrostatic analysis of complicated 3-D structures, IEEE Trans. Comput.-Aided Design Integr. Circuits Syst, 16, 10, pp. 1059-1072, (1997); Cuda Sparse Library (CUSP); Cuda Solver API; Schrefl T., Finite elements in numerical micromagnetics part I: Granular hard magnets, J. Magn. Magn. Mater, 207, 1-3, pp. 45-65, (1999); Fidler J., Schrefl T., Micromagnetic modelling-the current state of the art, J. Phys. D, Appl. Phys, 33, 15, pp. R135-R156, (2000); Schrefl T., Schabes M.E., Suess D., Stehno M., Dynamic micromagnetic write head fields during magnetic recording in granular media, IEEE Trans. Magn, 40, 4, pp. 2341-2343, (2004); Bashir A., Et al., Write head with DC current-driven energy-assisted magnetic recording, IEEE Trans. Magn, 58, 4, (2022); Ding Y., Zhao H., Bashir M.A., Goncharov A., Heijden Der Van P.A., Sub-nanosecond switching of spin-transfertorque device for energy-assisted perpendicular magnetic recording, IEEE Trans. Magn, 58, 4, pp. 1-6, (2022); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, 6, pp. 3443-3449, (2004); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z Sowjet, 8, pp. 153-169, (1935); Brown W.F., Micromagnetics, (1963); Hrkac G., Et al., Three-dimensional micromagnetic finite element simulations including eddy currents, J. Appl. Phys, 97, 10, (2005); Takano K., Et al., Micromagnetics and eddy current effects in magnetic recording heads, IEEE Trans. Magn, 43, 6, pp. 2184-2186, (2007); Couture S., Chang R., Volvach I., Goncharov A., Lomakin V., Coupled finite-element micromagnetic-Integral equation electromagnetic simulator for modeling magnetization-Eddy currents dynamics, IEEE Trans. Magn, 53, 12, pp. 1-9, (2017); Suess D., Et al., Time resolved micromagnetics using a preconditioned time integration method, J. Magn. Magn. Mater, 248, 2, pp. 298-311, (2002); Hindmarsh A.C., Et al., SUNDIALS: Suite of nonlinear and differential/ algebraic equation solvers, ACM Trans. Math. Soft, 31, 3, pp. 363-396, (2005); Brenner S., Scott R., The Mathematical Theory of Finite Element Methods, (2007); Jackson J.D., Classical Electrodynamics, (1998); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., Fast-Mag: Fast micromagnetic simulator for complex magnetic structures (invited), J. Appl. Phys, 109, 7, (2011); Rao S., Wilton D., Glisson A., Electromagnetic scattering by surfaces of arbitrary shape, IEEE Trans. Antennas Propag, AP-30, 3, pp. 409-418, (1982); Graglia R.D., On the numerical integration of the linear shape functions times the 3-D green's function or its gradient on a plane triangle, IEEE Trans. Antennas Propag, 41, 10, pp. 1448-1455, (1993); Goncharov A., Multilevel tensor grid acceleration of the finite element micromagnetics, Proc. 12th Joint MMM-Intermag Conf. CH, (2013); Livshitz B., Boag A., Bertram H.N., Lomakin V., Nonuniform grid algorithm for fast calculation of magnetostatic interactions in micromagnetics, J. Appl. Phys, 105, 7, (2009); Bashir M.A., Et al., DC current path optimization for energy-assisted magnetic recording, Proc. IEEE 33rd Magn. Recording Conf. (TMRC), pp. 1-3, (2022); Goncharov A., Bashir A., Heijden Der P.Van, Asymmetric far track erasure by domain walls in recording heads, Proc. 64th Annu. Conf. Magn. Magnetic Mater. (HD), pp. 1-9, (2019); Altair Flux Applications; Berkowitz A.E., Takano K., Exchange anisotropy-A review, J. Magn. Magn. Mater, 200, pp. 552-570, (1999); Hubert A., Schaefer R., Magnetic Domains the Analysis of Magnetic Microstructure, (1998); Mills R.T., Et al., Toward performance-portable PETSC for GPUbased exascale systems, Parallel Comput, 108, (2021)","A.V. Goncharov; Western Digital Corporation, San Jose, 95119, United States; email: alexander.goncharov@wdc.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85166327638" +"Liu Y.; Miranda I.P.; Johnson L.; Bergman A.; Delin A.; Thonig D.; Pereiro M.; Eriksson O.; Azimi-Mousolou V.; Sjöqvist E.","Liu, Yuefei (57219690389); Miranda, Ivan P. (57213479922); Johnson, Lee (58960535800); Bergman, Anders (7201460537); Delin, Anna (7004169543); Thonig, Danny (56010415900); Pereiro, Manuel (57201771406); Eriksson, Olle (7102293363); Azimi-Mousolou, Vahid (51161665900); Sjöqvist, Erik (7003413101)","57219690389; 57213479922; 58960535800; 7201460537; 7004169543; 56010415900; 57201771406; 7102293363; 51161665900; 7003413101","Quantum Analog of Landau-Lifshitz-Gilbert Dynamics","2024","Physical Review Letters","133","26","266704","","","","0","10.1103/PhysRevLett.133.266704","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85213832004&doi=10.1103%2fPhysRevLett.133.266704&partnerID=40&md5=bb17e4ac89619e4db255dab84ef7a8f8","Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, SE-10691, Sweden; Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Department of Physics and Electrical Engineering, Linnaeus University, Kalmar, SE-39231, Sweden; Swedish E-Science Research Center (SeRC), KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden; Wallenberg Initiative Materials Science for Sustainability (WISE), KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden; School of Science and Technology, Örebro University, Örebro, SE-701 82, Sweden; WISE-Wallenberg Initiative Materials Science, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Department of Applied Mathematics and Computer Science, Faculty of Mathematics and Statistics, University of Isfahan, Isfahan, 81746-73441, Iran","Liu Y., Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, SE-10691, Sweden; Miranda I.P., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden, Department of Physics and Electrical Engineering, Linnaeus University, Kalmar, SE-39231, Sweden; Johnson L., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Bergman A., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Delin A., Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, SE-10691, Sweden, Swedish E-Science Research Center (SeRC), KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden, Wallenberg Initiative Materials Science for Sustainability (WISE), KTH Royal Institute of Technology, Stockholm, SE-10044, Sweden; Thonig D., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden, School of Science and Technology, Örebro University, Örebro, SE-701 82, Sweden; Pereiro M., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Eriksson O., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden, WISE-Wallenberg Initiative Materials Science, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Azimi-Mousolou V., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden, Department of Applied Mathematics and Computer Science, Faculty of Mathematics and Statistics, University of Isfahan, Isfahan, 81746-73441, Iran; Sjöqvist E., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden","The Landau-Lifshitz-Gilbert (LLG) and Landau-Lifshitz (LL) equations play an essential role for describing the dynamics of magnetization in solids. While a quantum analog of the LL dynamics has been proposed in [Phys. Rev. Lett. 110, 147201 (2013)PRLTAO0031-900710.1103/PhysRevLett.110.147201], the corresponding quantum version of LLG remains unknown. Here, we propose such a quantum LLG equation that inherently conserves purity of the quantum state. We examine the quantum LLG dynamics of a dimer consisting of two interacting spin-12 particles. Our analysis reveals that, in the case of ferromagnetic coupling, the evolution of initially uncorrelated spins mirrors the classical LLG dynamics. However, in the antiferromagnetic scenario, we observe pronounced deviations from classical behavior, underscoring the unique dynamics of becoming a spinless state, which is nonlocally correlated. Moreover, when considering spins that are initially entangled, our study uncovers an unusual form of revival-type quantum correlation dynamics, which differs significantly from what is typically seen in open quantum systems. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the ""https://creativecommons.org/licenses/by/4.0/""Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by ""https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html""Bibsam.","","Dynamics; Ferromagnetism; Magnetic mirrors; Magnetic moments; Quantum entanglement; Quantum optics; Spin dynamics; dimer; Antiferromagnetics; Classical behavior; Ferromagnetic coupling; Landau Lifshitz equation; Landau-Lifshitz; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Quantum analog; Quantum correlations; Quantum state; article; controlled study; Antiferromagnetism","","","","","","","Gilbert T. L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, (2004); Landau L. D., Lifshitz E. M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, (1935); Eriksson O., Bergman A., Bergqvist L., Hellsvik J., Atomistic Spin Dynamics: Foundations and Applications, (2017); Pereiro M., Yudin D., Chico J., Etz C., Eriksson O., Bergman A., Topological excitations in a kagome magnet, Nat. Commun, 5, (2014); Evans R. F. L., Atxitia U., Chantrell R. W., Quantitative simulation of temperature-dependent magnetization dynamics and equilibrium properties of elemental ferromagnets, Phys. Rev. B, 91, (2015); Pankratova M., Miranda I. P., Thonig D., Pereiro M., Sjoqvist E., Delin A., Eriksson O., Bergman A., Heat-conserving three-temperature model for ultrafast demagnetization in nickel, Phys. Rev. B, 106, (2022); Chimata R., Isaeva L., Kadas K., Bergman A., Sanyal B., Mentink J. H., Katsnelson M. I., Rasing T., Kirilyuk A., Kimel A., Eriksson O., Pereiro M., All-thermal switching of amorphous Gd-Fe alloys: Analysis of structural properties and magnetization dynamics, Phys. Rev. B, 92, (2015); Wieser R., Comparison of quantum and classical relaxation in spin dynamics, Phys. Rev. Lett, 110, (2013); Wieser R., Description of a dissipative quantum spin dynamics with a Landau-Lifshitz/Gilbert like damping and complete derivation of the classical Landau-Lifshitz equation, Eur. Phys. J. B, 88, (2015); Wieser R., Derivation of a time dependent Schrödinger equation as the quantum mechanical Landau-Lifshitz-Bloch equation, J. Phys. Condens. Matter, 28, (2016); Lakshmanan M., Nakamura K., Landau-Lifshitz equation of ferromagnetism: Exact treatment of the Gilbert damping, Phys. Rev. Lett, 53, (1984); Breuer H.-P., Petruccione F., The Theory of Open Quantum Systems, (2007); Manzano D., A short introduction to the Lindblad master equation, AIP Adv, 10, (2020); The operator space of a spin-(Equation presented) particle is spanned by four operators, identity (Equation presented) and the three Pauli operators (Equation presented), (Equation presented), (Equation presented). This implies (Equation presented) operators for (Equation presented) such spins with the normalization condition removed; Werner R. F., Quantum states with Einstein-Podolsky-Rosen correlations admitting a hidden-variable model, Phys. Rev. A, 40, (1989); Horst B., Bartkiewicz K., Miranowicz A., Two-qubit mixed states more entangled than pure states: Comparison of the relative entropy of entanglement for a given nonlocality, Phys. Rev. A, 87, (2013); Clauser J. F., Horne M. A., Shimony A., Holt R. A., Proposed experiment to test local hidden-variable theories, Phys. Rev. Lett, 23, (1969); Horodecki R., Horodecki P., Horodecki M., Violating Bell inequality by mixed spin-(Equation presented) states: Necessary and sufficient condition, Phys. Lett. A, 200, (1995); Cirel'son B. S., Quantum generalizations of Bell's inequality, Lett. Math. Phys, 4, (1980); Steiauf D., Fahnle M., Damping of spin dynamics in nanostructures: An ab initio study, Phys. Rev. B, 72, (2005); Trauzettel B., Bulaev D. V., Loss D., Burkard G., Spin qubits in graphene quantum dots, Nat. Phys, 3, (2007); A Werner state is known to be nonlocal if (Equation presented); Bengtson C., Stenrup M., Sjoqvist E., Quantum nonlocality in the excitation energy transfer in the Fenna-Matthews-Olson complex, Int. J. Quantum Chem, 116, (2016)","Y. Liu; Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, AlbaNova University Center, Stockholm, SE-10691, Sweden; email: yuefei@kth.se; I.P. Miranda; Department of Physics and Astronomy, Uppsala University, Uppsala, Box 516, SE-751 20, Sweden; email: ivan.miranda@alumni.usp.br; E. Sjöqvist; Department of Physics and Astronomy, Uppsala University, Uppsala, Box 516, SE-751 20, Sweden; email: erik.sjoqvist@physics.uu.se","","American Physical Society","","","","","","00319007","","PRLTA","39879062","English","Phys Rev Lett","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85213832004" +"Pandey N.; Chauhan Y.S.","Pandey, Nilesh (57194501995); Chauhan, Yogesh Singh (14029622100)","57194501995; 14029622100","Multidomain Interactions in Perpendicular Magnetic Tunnel Junction (p-MTJ): Enabling Multistate MRAM","2023","IEEE Transactions on Electron Devices","70","5","","2304","2311","7","5","10.1109/TED.2023.3259927","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85151527991&doi=10.1109%2fTED.2023.3259927&partnerID=40&md5=068ef37c648279413f4433cf1ba3d2ee","Indian Institute of Technology-Kanpur, Department of Electrical Engineering, Kanpur, 208016, India","Pandey N., Indian Institute of Technology-Kanpur, Department of Electrical Engineering, Kanpur, 208016, India; Chauhan Y.S., Indian Institute of Technology-Kanpur, Department of Electrical Engineering, Kanpur, 208016, India","We present a comprehensive study of multidomain (MD) effects in a perpendicular magnetic tunnel junction (p-MTJ). The MD nucleation is considered in the free layer of MTJ, which alters the spatial net-magnetic field (Heff) and magnetization vector (Me). These variations in Heff and Me cause a reduction in the field-like and spin-transfer torques. Furthermore, due to the increased inertia, the switching probability of the MD state is smaller than that of the mono-domain state. We also show that MD formation in the free layer leads to multistate storage in a single MTJ device. We observe a trade-off between the device's multistate storage and tunnel magnetoresistance (TMR) ratio: an enhancement in the multistate leads to a reduction in the TMR ratio. MD texture in the free layer is obtained by the coupled solution of 2-D Poisson's equation with the ferromagnetic net energy state equation (MD demagnetization energy + exchange energy + Dzyaloshinskii-Moriya interaction (DMI) + Zeeman energy + anisotropy energy). Following that, the MD switching characteristics are captured by plugging Heff and Me into the Landau-Lifshitz-Gilbert (LLG) equation. Our work opens a new era of MD dynamics in the MTJ, which can be utilized to realize an efficient multistate magnetic random access memories (MRAM). © 1963-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnetic tunnel junction (MTJ); multistate memory","Boundary conditions; Economic and social effects; Equations of state; Magnetic domains; Magnetization; Poisson equation; Textures; Tunnel junctions; Free layers; Landau-Lifshitz-Gilbert equations; Magnetic domain walls; Magnetic random access memory; Magnetic tunnel junction; Magnetic tunneling; Multi-domains; Multi-state; Multi-state memory; Magnetostatics","","","","","","","Ikeda S., Et al., A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction, Nature Mater., 9, 9, pp. 721-724, (2010); Worledge D.C., Et al., Spin torque switching of perpendicular Ta|CoFeB|MgO-based magnetic tunnel junctions, Appl. Phys. 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(56459649300)","53865487200; 57204087084; 56459649300","Antiferromagnetic bimeron dynamics controlled by magnetic defects","2023","Journal of Magnetism and Magnetic Materials","587","","171219","","","","1","10.1016/j.jmmm.2023.171219","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85171378278&doi=10.1016%2fj.jmmm.2023.171219&partnerID=40&md5=033553b9a4156295120f0dc3ca5d5d25","Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, Rodovia Governador Mário Covas, Km 60, ES, São Mateus, 29932-540, Brazil; Department of Applied Physics, Graduate School of Engineering, Tohoku University, Miyagi, Sendai, 980-8578, Japan","Silva R.L., Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, Rodovia Governador Mário Covas, Km 60, ES, São Mateus, 29932-540, Brazil; Silva R.C., Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, Rodovia Governador Mário Covas, Km 60, ES, São Mateus, 29932-540, Brazil; Masaki Y., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Miyagi, Sendai, 980-8578, Japan","We investigate dynamics of an isolated bimeron in the antiferromagnetic system, in the presence of magnetic defects. The bimeron is driven by torques due to a spin-polarized current, which is incorporated into the Landau–Lifshitz–Gilbert (LLG) equation. We numerically solve the LLG equation, and find a breathing dynamics of the bimeron as well as its transverse motion owing to the defect potential. We also analyze the potential landscapes due to the interaction between the bimeron and a defect, and give a qualitative picture of the numerically obtained dynamics. © 2023 Elsevier B.V.","Antiferromagnetic; Bimeron; Defects; Simulation","Antiferromagnetism; Defects; Antiferromagnetic systems; Antiferromagnetics; Bimeron; Defect potentials; Landau-Lifshitz-Gilbert equations; Magnetic defects; Simulation; Spin-polarized currents; Transverse motions; Dynamics","","","","","Japan Society for the Promotion of Science, KAKEN, (JP19K14662, JP22H01221)","This work was supported by JSPS KAKENHI, Japan , Grants Nos. 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Mater., 480, pp. 171-185, (2019); Toscano D., Santece I.A., Guedes R.C.O., Assis H.S., Miranda A.L.S., de Araujo C.I.L., Sato F., Coura P.Z., Leonel S.A., Traps for pinning and scattering of antiferromagnetic skyrmions via magnetic properties engineering, J. Appl. Phys., 127, 19, (2020); Blasing R., Khan A.A., Filippou P.C., Garg C., Hameed F., Castrillon J., Parkin S.S.P., Magnetic racetrack memory: From physics to the cusp of applications within a decade, Proc. IEEE, 108, 8, pp. 1303-1321, (2020)","R.C. Silva; Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, São Mateus, Rodovia Governador Mário Covas, Km 60, ES, 29932-540, Brazil; email: rodrigo.c.silva@ufes.br","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85171378278" +"Çam N.; Akıncı Ü.","Çam, Necda (58763523700); Akıncı, Ümit (6506528888)","58763523700; 6506528888","Micromagnetic investigation of dynamic hysteresis and dynamic phase transition properties in Co, Fe and Ni nanodisks","2024","Physics Letters, Section A: General, Atomic and Solid State Physics","500","","129365","","","","2","10.1016/j.physleta.2024.129365","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85185564903&doi=10.1016%2fj.physleta.2024.129365&partnerID=40&md5=f3dabcc30475da6151df1a9d5c626ceb","The Graduate School of Natural and Applied Sciences, Dokuz Eylül University, Izmir, TR-35160, Turkey; Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey","Çam N., The Graduate School of Natural and Applied Sciences, Dokuz Eylül University, Izmir, TR-35160, Turkey; Akıncı Ü., Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey","We have investigated the dynamical hysteresis behaviors of Co,Fe, and Ni nanodisks under the effect of the time-dependent magnetic field by solving the Landau-Lifshitz-Gilbert equation with the OOMMF software. A nanodisk with a diameter of 360nm constructed in the xy plane is exposed to a sinusoidal x-directed magnetic field with varying frequency and amplitude values. All nanodisks exhibit intricate frequency-dependent variations in the hysteresis loop area, remanent magnetization, and coercive field. Our simulation results emphasize that while the dynamical order occurs exclusively in the x direction for Fe nanodisks, dynamical order is observed in the y and z directions for Ni nanodisks within a specific frequency range. © 2024 Elsevier B.V.","Coercive field; Dynamic hysteresis; Hysteresis loop area; LLG equation; Micromagnetism; Remanent magnetization","Coercive force; Hysteresis; Magnetic fields; Magnetic materials; Magnetization; Coercive field; Dynamic hysteresis; Dynamic phase transition; Hysteresis loop area; LLG equation; Micromagnetics; Micromagnetisms; Nanodisks; Phase transition properties; Remanent magnetization; Hysteresis loops","","","","","","","Banobre-Lopez M., Teijeiro A., Rivas J., Rep. Pract. Oncol. Radiotherapy, 18, (2013); Shaterabadi Z., Nabiyouni G., Soleymani M., Prog. Biophys. Mol. Biol., 133, (2018); Khan A.U., Chen L., Ge G., Inorg. Chem. Commun., 134, (2021); Matsui I., J. Chem. Eng. 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Mater., 473, (2019); Thorat N.D., Bohara R., Yadav H.M., Otari S.V., Pawar S.H., Tofail S.A.M., 21 - Multifunctional Magnetic Nanostructures for Cancer Hyperthermia Therapy, Editor(s): Alina Maria Holban, Alexandru Mihai Grumezescu, Nanoarchitectonics for Smart Delivery and Drug Targeting, (2016); Donahue M.J., Porter D.G., (1999); Trudel S., Gaier O., Hamrle J., Hillebrands B., J. Phys. D, Appl. Phys., 43, 19, (2010); Kronmuller H., Micromagnetism and the Microstructure of Ferromagnetic Solids, (2003); Dang Xuan N., Dopke C., Blachowicz T., Ehrmann A., Acta Phys. Pol. A, 137, 3, (2020); Djuhana D., Kurniawan C., Kim D.-H., Widodo A.T., Int. J. Technol., 12, 3, (2021); Cam N., Akinci U., Ground state dynamic hysteresis properties of permalloy nanodisk with varying shapes, J. Supercond. Nov. Magn., (2023)","Ü. Akıncı; Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey; email: umit.akinci@deu.edu.tr","","Elsevier B.V.","","","","","","03759601","","PYLAA","","English","Phys Lett Sect A Gen At Solid State Phys","Article","Final","","Scopus","2-s2.0-85185564903" +"Zhang Z.-N.; Jia Z.-L.; Xue D.-S.","Zhang, Ze-Nan (58960114100); Jia, Zhen-Lin (57654036600); Xue, De-Sheng (55447216200)","58960114100; 57654036600; 55447216200","Analytical solutions to the precession relaxation of magnetization with uniaxial anisotropy","2024","Chinese Physics B","33","4","047502","","","","0","10.1088/1674-1056/ad08a3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85188923542&doi=10.1088%2f1674-1056%2fad08a3&partnerID=40&md5=a50b764b6487d4ce8db86cf6564656b8","Key Laboratory for Magnetism and Magnetic Materials, the Ministry of Education, Lanzhou University, Lanzhou, 730000, China","Zhang Z.-N., Key Laboratory for Magnetism and Magnetic Materials, the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; Jia Z.-L., Key Laboratory for Magnetism and Magnetic Materials, the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; Xue D.-S., Key Laboratory for Magnetism and Magnetic Materials, the Ministry of Education, Lanzhou University, Lanzhou, 730000, China","Based on the Landau-Lifshitz-Gilbert (LLG) equation, the precession relaxation of magnetization is studied when the external field H is parallel to the uniaxial anisotropic field H k. The evolution of three-component magnetization is solved analytically under the condition of H = nH k (n = 3, 1 and 0). It is found that with an increase of H or a decrease of the initial polar angle of magnetization, the relaxation time decreases and the angular frequency of magnetization increases. For comparison, the analytical solution for H k = 0 is also given. When the magnetization becomes stable, the angular frequency is proportional to the total effective field acting on the magnetization. The analytical solutions are not only conducive to the understanding of the precession relaxation of magnetization, but also can be used as a standard model to test the numerical calculation of LLG equation. © 2024 Chinese Physical Society and IOP Publishing Ltd.","analytical solutions; Landau-Lifshitz-Gilbert (LLG) equation; precession relaxation; uniaxial anisotropy","Anisotropy; Analytical solution; Angular frequencies; Anisotropic fields; Condition; External fields; Landau-Lifshitz-Gilbert equations; Precession relaxation; Relaxation of magnetization; Three-component; Uniaxial anisotropy; Magnetization","","","","","National Key Research and Development Program of China, NKRDPC, (2021YFB3501300); National Key Research and Development Program of China, NKRDPC; National Natural Science Foundation of China, NSFC, (91963201, 12174163); National Natural Science Foundation of China, NSFC; Higher Education Discipline Innovation Project, (B20063); Higher Education Discipline Innovation Project","Project supported by the National Key R&D Program of China (Grant No. 2021YFB3501300), the National Natural Science Foundation of China (Grant Nos. 91963201 and 12174163), and the 111 Project (Grant No. B20063).","Zhong W D, Ferromagnetism, 2, (2017); Wood R, J. 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Phys.","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85188923542" +"Bhattacharjee S.; Lee S.-C.","Bhattacharjee, Satadeep (7102306250); Lee, Seung-Cheol (55716364200)","7102306250; 55716364200","Magnetization dynamics in skyrmions due to high-speed carrier injections from Dirac half-metals","2024","Journal of Physics Condensed Matter","36","47","475801","","","","0","10.1088/1361-648X/ad6f65","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85202730002&doi=10.1088%2f1361-648X%2fad6f65&partnerID=40&md5=53d318538e5f3889b974eaf2f1da2d9a","Indo-Korea Science and Technology Center (IKST), Bangalore, India; Electronic Materials Research Center, Korea Institute of Science & Technology, Seoul, South Korea","Bhattacharjee S., Indo-Korea Science and Technology Center (IKST), Bangalore, India; Lee S.-C., Electronic Materials Research Center, Korea Institute of Science & Technology, Seoul, South Korea","Recent developments in the magnetization dynamics in spin textures, particularly skyrmions, offer promising new directions for magnetic storage technologies and spintronics. Skyrmions, characterized by their topological protection and efficient mobility at low current density, are increasingly recognized for their potential applications in next-generation logic and memory devices. This study investigates the dynamics of skyrmion magnetization, focusing on the manipulation of their topological states as a basis for bitwise data storage through a modified Landau-Lifshitz-Gilbert equation (LLG). We introduce spin-polarized electrons from a topological ferromagnet that induce an electric dipole moment that interacts with the electric gauge field within the skyrmion domain. This interaction creates an effective magnetic field that results in a torque that can dynamically change the topological state of the skyrmion. In particular, we show that these torques can selectively destroy and create skyrmions, effectively writing and erasing bits, highlighting the potential of using controlled electron injection for robust and scalable skyrmion-based data storage solutions. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.","magnetic memory; quantum magnet; skyrmion; topological ferromagnet","Directed graphs; Ferromagnetism; Magnetic core storage; Magnetic logic devices; Magnetic recording; Spin dynamics; Spin polarization; Spintronics; Virtual storage; metal; Carrier injection; Data storage; Ferromagnets; High Speed; Magnetic memory; Magnetization dynamics; Quantum magnets; Skyrmions; Topological ferromagnet; Topological state; article; controlled study; current density; data mining; dipole; dynamics; electric potential; electron; human; information storage; magnet; magnetic field; memory; torque; velocity; Magnetization","","","","","Ministry of Science, ICT and Future Planning, MSIP; Korea Institute of Science and Technology, KIST, (2V6760)","This work was supported by the Korea Institute of Science and Technology, GKP (Global Knowledge Platform, Grant number 2V6760) project of the Ministry of Science, ICT and Future Planning.","Wang X, Hu X C, Wu H T, Commun. 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Bhattacharjee; Indo-Korea Science and Technology Center (IKST), Bangalore, India; email: s.bhattacharjee@ikst.res.in","","Institute of Physics","","","","","","09538984","","JCOME","39142328","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85202730002" +"Castro C.J.; Ortega-Piwonka I.; Malomed B.A.; Urzagasti D.; Pedraja-Rejas L.; Díaz P.; Laroze D.","Castro, Camilo José (57191954607); Ortega-Piwonka, Ignacio (57144614900); Malomed, Boris A. (35555126200); Urzagasti, Deterlino (55970090900); Pedraja-Rejas, Liliana (55663652200); Díaz, Pablo (57193860852); Laroze, David (8450437100)","57191954607; 57144614900; 35555126200; 55970090900; 55663652200; 57193860852; 8450437100","Breather Bound States in a Parametrically Driven Magnetic Wire","2024","Symmetry","16","12","1565","","","","0","10.3390/sym16121565","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85213237179&doi=10.3390%2fsym16121565&partnerID=40&md5=3b13c384bcd503da2eb558d5916ba051","Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica, 1000000, Chile; Carrera de Física, Universidad Mayor de San Andrés, La Paz 8635, Bolivia, Bolivia; Grupo de Dinámica No Lineal, Caos y Sistemas Complejos, Universidad Rey Juan Carlos, Tulipán s/n, Móstoles, 28933, Spain; Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, and Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, 69978, Israel; Departamento de Ingeniería Industrial y de Sistemas, Universidad de Tarapacá, Casilla 7D, Arica, 1000000, Chile; Departamento de Ciencias Físicas, Universidad de La Frontera, Casilla 54-D, Temuco, 4811230, Chile","Castro C.J., Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica, 1000000, Chile, Carrera de Física, Universidad Mayor de San Andrés, La Paz 8635, Bolivia, Bolivia; Ortega-Piwonka I., Grupo de Dinámica No Lineal, Caos y Sistemas Complejos, Universidad Rey Juan Carlos, Tulipán s/n, Móstoles, 28933, Spain; Malomed B.A., Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, and Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, 69978, Israel; Urzagasti D., Carrera de Física, Universidad Mayor de San Andrés, La Paz 8635, Bolivia, Bolivia; Pedraja-Rejas L., Departamento de Ingeniería Industrial y de Sistemas, Universidad de Tarapacá, Casilla 7D, Arica, 1000000, Chile; Díaz P., Departamento de Ciencias Físicas, Universidad de La Frontera, Casilla 54-D, Temuco, 4811230, Chile; Laroze D., Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica, 1000000, Chile","We report the results of a systematic investigation of localized dynamical states in the model of a one-dimensional magnetic wire, which is based on the Landau–Lifshitz–Gilbert (LLG) equation. The dissipative term in the LLG equation is compensated by the parametric drive imposed by the external AC magnetic field, which is uniformly applied perpendicular to the rectilinear wire. The existence and stability of the localized states is studied in the plane of the relevant control parameters, namely, the amplitude of the driving term and the detuning of its frequency from the parametric resonance. With the help of systematically performed simulations of the LLG equation, the existence and stability areas are identified in the parameter plane for several species of the localized states: stationary single- and two-soliton modes, single and double breathers, drifting double breathers with spontaneously broken inner symmetry, and multisoliton complexes. Multistability occurs in this system. The breathers emit radiation waves (which explains their drift caused by the spontaneous symmetry breaking, as it breaks the balance between the recoil from the waves emitted to left and right), while the multisoliton complexes exhibit cycles of periodic transitions between three-, five-, and seven-soliton configurations. Dynamical characteristics of the localized states are systematically calculated too. These include, in particular, the average velocity of the asymmetric drifting modes, and the largest Lyapunov exponent, whose negative and positive values imply that the intrinsic dynamics of the respective modes is regular or chaotic, respectively. © 2024 by the authors.","dispersive radiation; Landau–Lifshitz equation; Lyapunov exponents; multistability; soliton dynamics","","","","","","Fondo Nacional de Desarrollo Científico y Tecnológico, FONDECYT; Israel Science Foundation, ISF, (1695/22); Israel Science Foundation, ISF","The work of B.A.M. was supported, in part, by the Israel Science Foundation through grant No. 1695/22. P.D. and D.L. acknowledge partial financial support from FONDECYT 1231020.","Aranson I.S., Kramer L., The world of the complex Ginzburg-Landau equation, Rev. Mod. Phys, 74, pp. 99-143, (2002); Rosanov N.N., Spatial Hysteresis and Optical Patterns, (2013); Lugiato L.A., Lefever R., Spatial Dissipative Structures in Passive Optical Systems, Phys. Rev. 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Lett, 141, (2023); Yin X., Xu L., Yang L., Evolution and interaction of soliton solutions of Rossby waves in geophysical fluid mechanics, Nonlinear Dyn, 111, pp. 12433-12445, (2023)","D. Laroze; Instituto de Alta Investigación, Universidad de Tarapacá, Arica, Casilla 7D, 1000000, Chile; email: dlarozen@academicos.uta.cl","","Multidisciplinary Digital Publishing Institute (MDPI)","","","","","","20738994","","","","English","Symmetry","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85213237179" +"Saldanha-Bautista D.E.; Padrón-Hernández E.","Saldanha-Bautista, D.E. (57927749300); Padrón-Hernández, E. (6504643531)","57927749300; 6504643531","Magnetostatic (MSW) modes in a Dielectric@Ferromagnetic (Core@Shell) spherical structure","2023","Physica B: Condensed Matter","670","","415342","","","","0","10.1016/j.physb.2023.415342","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85172450000&doi=10.1016%2fj.physb.2023.415342&partnerID=40&md5=7108a4992b101d786b71a98950145e2d","Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil","Saldanha-Bautista D.E., Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil; Padrón-Hernández E., Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil","The solutions for magnetostatic spin waves (MSW) modes in a spherical structure were studied. A spherical core@shell structure, of soft ferromagnetic (FM) shell and a dielectric core material, was the geometry used for the calculation by solving the Walker equation. The dielectric is a sphere of radius r1 covered by an FM shell of inner radius r1 and outer radius r2. The transformation of the Walker equation in the FM shell was performed based on the solution proposed by Plumier. The resultant expression of solution presented here for the MSW modes are not reported in the literature. The solution involves integrals that are solved numerically and the result are the dispersion relations curves. These curves show deviations from the solution for an empty shell with no core (vacuum@FM) previously reported. The changes in the presented curves are mainly due to the displacement currents that arise in the dielectric core. The curves were calculated for silica and for alumina core, the most commonly used to grow spherical shells. This result here is important because hollow spherical structures are usually grown on dielectric support. © 2023 Elsevier B.V.","Dielectric@Ferromagnetic; LLG equation; Magnetostatic modes","Aluminum oxide; Coremaking; Ferromagnetic materials; Ferromagnetism; Frequency modulation; Magnetostatics; Shells (structures); Silica; Spheres; Core shell; Dielectric core; Dielectric@ferromagnetic; Ferromagnetic cores; Ferromagnetics; LLG equation; Magnetostatic modes; Magnetostatic spin waves; Spherical structures; Spin-wave mode; Alumina","","","","","Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq; Financiadora de Estudos e Projetos, FINEP; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, FACEPE","The authors are grateful to the Brazilian Agencies: CAPES ; CNPq ; FINEP and FACEPE .","Ansalone P., Basso V., Walker's modes in ferromagnetic finite hollow cylinder, Physica B, 578, (2020); Dobrovolskiy O.V., Bunyaev S.A., Vovk N.R., Navas D., Gruszecki P., Krawczyk M., Sachser R., Huth M., Chumak A.V., Guslienko K.Y., Et al., Spin-wave spectroscopy of individual ferromagnetic nanodisks, Nanoscale, 12, 41, pp. 21207-21217, (2020); Wang J., Loh K.P., Zhong Y.L., Lin M., Ding J., Foo Y.L., Bifunctional FePt coreshell and hollow spheres: sonochemical preparation and self-assembly, Chem. 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A, 453, (2022); Plumier R., Magnetostatic modes in a sphere and polarization current corrections, Physica, 28, 4, pp. 423-444, (1962); Ishak W., Magnetostatic wave technology: a review, Proc. IEEE, 76, 2, pp. 171-187, (1988)","E. Padrón-Hernández; Departamento de Física, Universidade Federal de Pernambuco, Recife, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, 50740-540, Brazil; email: eduardo.hernandez@ufpe.br","","Elsevier B.V.","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-85172450000" +"Zheng Z.; Qi S.; Li X.","Zheng, Zhoushun (7403001159); Qi, Sai (59334341600); Li, Xinye (58553118900)","7403001159; 59334341600; 58553118900","A radial basis function-finite difference method for solving Landau–Lifshitz–Gilbert equation including Dzyaloshinskii-Moriya interaction","2024","Engineering Analysis with Boundary Elements","169","","105966","","","","0","10.1016/j.enganabound.2024.105966","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85204343432&doi=10.1016%2fj.enganabound.2024.105966&partnerID=40&md5=a3774347420013174a4a8454cf78ace3","School of Mathematics and Statistics, Central South University, Hunan, China","Zheng Z., School of Mathematics and Statistics, Central South University, Hunan, China; Qi S., School of Mathematics and Statistics, Central South University, Hunan, China; Li X., School of Mathematics and Statistics, Central South University, Hunan, China","This paper investigates a numerical method for solving the two-dimensional Landau–Lifshitz–Gilbert (LLG) equation, governing the dynamics of the magnetization in ferromagnetic materials. Specifically, we incorporate the Dzyaloshinskii–Moriya interaction into the LLG equation—a crucial factor for the creation and stabilization of magnetic skyrmions. We propose a local meshless method that utilizes radial basis function-finite difference (RBF-FD) for spatial discretization and the Crank–Nicolson scheme for temporal discretization, along with an extrapolation technique to handle the nonlinear terms. We demonstrate the method's accuracy, efficiency, and adaptability through numerical tests on domains of various shapes, showcasing its practical utility in simulating real-world magnetic phenomena and advanced materials. © 2024 Elsevier Ltd","Landau–Lifshitz–Gilbert equation; Local meshless methods; Radial basis functions; Skyrmion","Convergence of numerical methods; Extrapolation; Finite difference method; Base function; Dzyaloshinskii-Moriya interaction; Finite-difference methods; Landau-Lifshitz-Gilbert equations; Local meshless method; Meshless methods; Radial base function; Radial basis; Skyrmions; Two-dimensional; Ferromagnetic materials","","","","","National Natural Science Foundation of China, NSFC, (12201644, 51974377); National Natural Science Foundation of China, NSFC; Natural Science Foundation of Hunan Province, (2023JJ40693); Natural Science Foundation of Hunan Province","This work is supported by National Natural Science Foundation of China - Grant No. 12201644 , 51974377 and Natural Science Foundation of Hunan Province - Grant No. 2023JJ40693 .","Romming N., Hanneken C., Menzel M., Bickel J.E., Wolter B., von Bergmann K., Kubetzka A., Wiesendanger R., Writing and deleting single magnetic skyrmions, Science, 341, 6146, pp. 636-639, (2013); Jiang W., Upadhyaya P., Zhang W., Yu G., Jungfleisch M.B., Fradin F.Y., Pearson J.E., Tserkovnyak Y., Wang K.L., Heinonen O., Et al., Blowing magnetic skyrmion bubbles, Science, 349, 6245, pp. 283-286, (2015); Back C., Cros V., Ebert H., Everschor-Sitte K., Fert A., Garst M., Ma T., Mankovsky S., Monchesky T.L., Mostovoy M., Nagaosa N., Parkin S.S.P., Pfleiderer C., Reyren N., Rosch A., Taguchi Y., Tokura Y., von Bergmann K., Zang J., The 2020 skyrmionics roadmap, J Phys D: Appl Phys, 53, 36, (2020); Zhang X., Zhou Y., Ezawa M., Antiferromagnetic skyrmion: stability, creation and manipulation, Sci Rep, 6, 1, (2016); Hu J., Yang T., Chen L., Stability and dynamics of skyrmions in ultrathin magnetic nanodisks under strain, Acta Mater, 183, pp. 145-154, (2020); Kolesnikov A.G., Stebliy M.E., Samardak A.S., Ognev A.V., Skyrmionium–high velocity without the skyrmion Hall effect, Sci Rep, 8, 1, (2018); Hubert A., Schafer R., Magnetic domains: The analysis of magnetic microstructures, (2008); Davoli E., Di Fratta G., Praetorius D., Ruggeri M., Micromagnetics of thin films in the presence of Dzyaloshinskii–Moriya interaction, Math Models Methods Appl Sci, 32, 5, pp. 911-939, (2022); E W., Wang X., Numerical methods for the Landau–Lifshitz equation, SIAM J Numer Anal, 38, 5, pp. 1647-1665, (2000); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau–Lifshitz–Gilbert equation, SIAM J Numer Anal, 44, 4, pp. 1405-1419, (2006); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch Comput Methods Eng, 15, 3, pp. 1-37, (2007); Alouges F., Kritsikis E., Steiner J., Toussaint J.-C., A convergent and precise finite element scheme for Landau–Lifschitz–Gilbert equation, Numer Math, 128, 3, pp. 407-430, (2014); An R., Gao H., Sun W., Optimal error analysis of Euler and Crank–Nicolson projection finite difference schemes for Landau–Lifshitz equation, SIAM J Numer Anal, 59, 3, pp. 1639-1662, (2021); Akrivis G., Feischl M., Kovacs B., Lubich C., Higher-order linearly implicit full discretization of the Landau–Lifshitz–Gilbert equation, Math Comp, 90, 329, pp. 995-1038, (2021); Chen J., Wang C., Xie C., Convergence analysis of a second-order semi-implicit projection method for Landau–Lifshitz equation, Appl Numer Math, 168, pp. 55-74, (2021); Cheng Q., Shen J., Length preserving numerical schemes for Landau–Lifshitz equation based on Lagrange multiplier approaches, SIAM J Sci Comput, 45, 2, pp. A530-A553, (2023); Hrkac G., Pfeiler C.-M., Praetorius D., Ruggeri M., Segatti A., Stiftner B., Convergent tangent plane integrators for the simulation of chiral magnetic skyrmion dynamics, Adv Comput Math, 45, pp. 1329-1368, (2019); Li P., Gu S., Lan J., Chen J., Ren W., Du R., Micromagnetics simulations and phase transitions of ferromagnetics with Dzyaloshinskii–Moriya interaction, Commun Nonlinear Sci Numer Simul, 126, (2023); Belytschko T., Krongauz Y., Organ D., Fleming M., Krysl P., Meshless methods: an overview and recent developments, Comput Methods Appl Mech Engrg, 139, 1-4, pp. 3-47, (1996); Fasshauer G.E., Meshfree approximation methods with MATLAB, (2007); 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Gunderman D., Flyer N., Fornberg B., Transport schemes in spherical geometries using spline-based RBF-FD with polynomials, J Comput Phys, 408, (2020); Rabczuk T., Ren H., Zhuang X., A nonlocal operator method for partial differential equations with application to electromagnetic waveguide problem, Comput Mater Continua, 59, 1, pp. 31-55, (2019); Ren H., Zhuang X., Rabczuk T., A nonlocal operator method for solving partial differential equations, Comput Methods Appl Mech Engrg, 358, (2020); Samaniego E., Anitescu C., Goswami S., Nguyen-Thanh V.M., Guo H., Hamdia K., Zhuang X., Rabczuk T., An energy approach to the solution of partial differential equations in computational mechanics via machine learning: Concepts, implementation and applications, Comput Methods Appl Mech Engrg, 362, (2020); Flyer N., Fornberg B., Bayona V., Barnett G.A., On the role of polynomials in RBF-FD approximations: I. Interpolation and accuracy, J Comput Phys, 321, pp. 21-38, (2016); Bayona V., Flyer N., Fornberg B., Barnett G.A., On the role of polynomials in RBF-FD approximations: II. Numerical solution of elliptic PDEs, J Comput Phys, 332, pp. 257-273, (2017); Bayona V., Flyer N., Fornberg B., On the role of polynomials in RBF-FD approximations: III. Behavior near domain boundaries, J Comput Phys, 380, pp. 378-399, (2019); Persson P.-O., Strang G., A simple mesh generator in matlab, SIAM Rev, 46, 2, pp. 329-345, (2004); Beg M., Carey R., Wang W., Cortes-Ortuno D., Vousden M., Bisotti M.-A., Albert M., Chernyshenko D., Hovorka O., Stamps R.L., Et al., Ground state search, hysteretic behaviour and reversal mechanism of skyrmionic textures in confined helimagnetic nanostructures, Sci Rep, 5, 1, (2015)","X. Li; School of Mathematics and Statistics, Central South University, Hunan, China; email: xinye.li@csu.edu.cn","","Elsevier Ltd","","","","","","09557997","","EABAE","","English","Eng Anal Boundary Elem","Article","Final","","Scopus","2-s2.0-85204343432" +"Hu Y.; Du A.","Hu, Yue (59116176300); Du, An (7006264005)","59116176300; 7006264005","Magnetic properties of twisted bilayer magnetic thin films with interlayer dipolar interaction","2023","Journal of Magnetism and Magnetic Materials","588","","171374","","","","0","10.1016/j.jmmm.2023.171374","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85174395671&doi=10.1016%2fj.jmmm.2023.171374&partnerID=40&md5=7b0ee5c71ae38524b6a96b7f32c60d8b","College of Science, Northeastern University, Shenyang, 110819, China; National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China","Hu Y., College of Science, Northeastern University, Shenyang, 110819, China; Du A., College of Science, Northeastern University, Shenyang, 110819, China, National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China","In this paper, a model of bilayer film with single-ion anisotropy in z-direction and ferromagnetic exchange interaction in the layer and dipolar interaction between layers is established. The influence of dipolar interaction intensity on the magnetic properties of the system at different interlayer twisted angles θ was studied by using Landau Lifshitz Gilbert (LLG) equation. At zero temperature it is found that the system will be in the z-direction ferromagnetic state when the interlayer dipolar interaction intensity is small, but the state will become the z-direction magnetic domain structure when the interlayer dipolar interaction intensity is greater than a certain value. When θ = 0°, the Curie temperature and coercivity of the system decrease with the increase of dipolar interaction intensity, while the resonant frequency increases with the increase of dipolar interaction intensity. When θ ≠ 0°, if the interlayer dipolar interaction intensity is small, the change of θ has little effect on the magnetic properties, but the Curie temperature, coercivity and resonance frequency are slightly lower than that at θ = 0° when the interlayer dipolar interaction is big. When θ is larger than a certain angle, the change of θ has almost no effect on coercivity and resonance frequency, which is similar to the change of the total energy of the system. © 2023 Elsevier B.V.","Bilayer structure; Dipolar interaction; LLG equation; Magnetic properties","Curie temperature; Ferromagnetic materials; Ferromagnetism; Ion exchange; Magnetic domains; Natural frequencies; Bi-layer films; Bi-layer structure; Dipolar interaction; Ferromagnetic exchange interaction; Landau-Lifshitz-Gilbert equations; Layer interaction; Resonance frequencies; Single ion anisotropy; Twisted bilayers; Z-directions; Coercive force","","","","","Higher Education Discipline Innovation Project, (B16009); Higher Education Discipline Innovation Project","This research was supported by the 111 Project (B16009).","Melzer M., Kaltenbrunner M., Makarov D., Karnaushenko D., Karnaushenko D., Sekitani T., Someya T., Schmidt O.G., Imperceptible magnetoelectronics, Nat. 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Du; College of Science, Northeastern University, Shenyang, 110819, China; email: duan@mail.neu.edu.cn","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85174395671" +"Guan Z.-J.; Yang B.-A.; Sun X.-Y.; Li Y.; Jiang J.-T.; Song B.; Gong Y.-X.; Zhen L.","Guan, Zhen-Jie (57202382782); Yang, Bo-An (58628956100); Sun, Xue-Yin (33867825200); Li, Yang (58446700100); Jiang, Jian-Tang (55250394900); Song, Bo (57203272975); Gong, Yuan-Xun (24586946600); Zhen, Liang (59117602200)","57202382782; 58628956100; 33867825200; 58446700100; 55250394900; 57203272975; 24586946600; 59117602200","SiC/Co composite fibers with enhanced conductivity and magnetic coupling developed for reinforcing and high-efficiency electromagnetic absorbing (EMA) materials","2023","Composites Part B: Engineering","266","","111010","","","","20","10.1016/j.compositesb.2023.111010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85173061936&doi=10.1016%2fj.compositesb.2023.111010&partnerID=40&md5=0ae8d3be94fd3fa897f409967e912eaf","School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; School of Materials and Metallurgy, University of Science and Technology Liaoning, Liaoning, 114051, China; MOE Key Laboratory of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China; National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin, 150080, China; Aerospace Research Institute of Special Material and Processing Technology, Beijing, 100074, China","Guan Z.-J., School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; Yang B.-A., School of Materials and Metallurgy, University of Science and Technology Liaoning, Liaoning, 114051, China; Sun X.-Y., School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; Li Y., MOE Key Laboratory of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China; Jiang J.-T., School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; Song B., National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin, 150080, China; Gong Y.-X., Aerospace Research Institute of Special Material and Processing Technology, Beijing, 100074, China; Zhen L., School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China, MOE Key Laboratory of Micro-System and Micro-Structures Manufacturing, Harbin Institute of Technology, Harbin, 150080, China","For the design requirements for structural/functional integrated components, it is urgent to find EMA materials combining high-efficient EMA performances and load bearing capacity. Herein, high-strength SiC fibers are modified by Co nanoparticles to construct SiC/Co composite fibers by the liquid-phase method and subsequent hydrogen-thermal annealing. The conductivity of single SiC/Co fiber can be improved by increasing the diameter and content of Co nanoparticles, which leads to enhanced conduction loss and then dominates the dielectric loss. The cross-linked SiC/Co fibers with high conductivity also contribute to significant eddy current loss. Micromagnetic simulation based on Landau-Lifshitz-Gilbert equation (LLG) quantificationally reveals that reducing Co diameter from 140 nm to 30 nm can enhance the ferromagnetic loss by 17.19 times, and this law also can be confirmed by the effect medium theory. Maximum reflection loss (RLmax) can reach −78.0 dB at 11.8 GHz and effective absorbing bandwidth with RL < −10 dB (ERL10) of 6.6 GHz can be observed in these SiC/Co-400 filled specimens with the thickness of only 2.7 mm. These SiC/Co fibers present excellent absorbing performances and display the potential for developing into load-bearing and high-efficiency EMA materials. © 2023 Elsevier Ltd","Conductivity; Electromagnetic absorption; Micromagnetic simulation; SiC/Co","Cobalt; Dielectric losses; Efficiency; Fibers; Magnetic couplings; Nanomagnetics; Nanoparticles; Silicon; Absorbing materials; Co Nanoparticles; Composite fibres; Conductivity; Electromagnetic absorbing; Enhanced conductivity; Higher efficiency; Micromagnetic simulations; Performance; SiC/co; Silicon carbide","","","","","National Key Laboratory of Science, Technology on Advanced Composites in Special Environments, HIT","This work was financially supported by the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments . 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Liang C., Liu C., Wang H., Wu L., Jiang Z., Xu Y., Et al., SiC–Fe3O4 dielectric–magnetic hybrid nanowires: controllable fabrication, characterization and electromagnetic wave absorption, J Mater Chem A, 2, 39, pp. 16397-16402, (2014); Kuang B., Dou Y., Wang Z., Ning M., Jin H., Guo D., Et al., Enhanced microwave absorption properties of Co-doped SiC at elevated temperature, Appl Surf Sci, 445, pp. 383-390, (2018); Hu W., Wang L., Wu Q., Wu H., Preparation, characterization and microwave absorption properties of bamboo-like β-SiC nanowhiskers by molten-salt synthesis, J Mater Sci Mater Electron, 25, 12, pp. 5302-5308, (2014)","L. Zhen; School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; email: lzhen@hit.edu.cn; X.-Y. Sun; School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; email: hit2001sun@hit.edu.cn; J.-T. Jiang; School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China; email: jjtcy@hit.edu.cn","","Elsevier Ltd","","","","","","13598368","","CPBEF","","English","Compos Part B: Eng","Article","Final","","Scopus","2-s2.0-85173061936" +"Nishino M.; Miyashita S.","Nishino, Masamichi (7103009415); Miyashita, Seiji (7102333760)","7103009415; 7102333760","Atomistic Model Study on Magnetic Properties of Permanent Magnets―Treatment of Thermal Fluctuation and Thermal Effects, and Future Perspective―; [原子論的スピンモデルによる永久磁石の磁気特性の研究―熱揺らぎおよび温度効果の取り扱いと将来展望―]","2023","Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals","87","5","","158","172","14","0","10.2320/JINSTMET.JA202202","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85161516769&doi=10.2320%2fJINSTMET.JA202202&partnerID=40&md5=a6ec271d65b5d2b183a109714ab649a8","National Institute for Materials Science, Tsukuba, 305–0047, Japan; Graduate School of Science, The University of Tokyo, Tokyo, 113–0033, Japan","Nishino M., National Institute for Materials Science, Tsukuba, 305–0047, Japan; Miyashita S., Graduate School of Science, The University of Tokyo, Tokyo, 113–0033, Japan","We review atomistic spin model studies, a new approach for theoretical investigations, on magnetic properties of permanent magnets. In the atomistic modeling, the microscopic details of magnetic parameters and lattice structures are realistically considered, and the temperature effect, including thermal fluctuation, is properly treated based on statistical physics methods: Monte Caro methods and stochastic Landau–Lifshitz–Gilbert equation methods. We introduce how to treat thermal effects for static and dynamical properties using these methods. Focusing especially on neodymium permanent magnets, we discuss features of magnetization, domain wall, coercivity of a grain, nucleation and pinning fields, and dysprosium substitution effect, which were first elucidated with those methods. ［doi:10.2320/jinstmet.JA202202］ © 2023 Japan Institute of Metals (JIM). All rights reserved.","atomistic spin model; Monte Caro method; permanent magnets; stochastic Landau–Lifshitz–Gilbert (LLG) equation; thermal effects; thermal fluctuation","Domain walls; Rare earths; Statistical Physics; Stochastic models; Stochastic systems; Thermal effects; Atomistic modelling; Atomistic spin model; Atomistics; Landau-Lifshitz-Gilbert equations; Modelling studies; Monte caro method; Spin models; Stochastic landau–lifshitz–gilbert equation; Stochastics; Thermal fluctuations; Permanent magnets","","","","","","","Sagawa M., Hirosawa S., J. Mater. Res, 3, pp. 45-54, (1988); Hirosawa S., Matsuura Y., Yamamoto H., Fujimura S., Sagawa M., Yamauchi H., Jpn. J. Appl. Phys, 24, (1985); Herbst J.F., Rev. Mod. Phys, 63, pp. 819-898, (1991); Hirosawa S., Matsuura Y., Yamamoto H., Fujimura S., Sagawa M., Yamauchi H., J. Appl. Phys, 59, pp. 873-879, (1986); Andreev A.V., Deryagin A.V., Kudrevatykh N.V., Mushnikov N.V., Reimer V.A., Terent'ev S.V., Sov. Phys. 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Mater, 3, (2019); Gong Q., Yi M., Evans R.F.L., Gutfleisch O., Xu B.-X., Mater. Res. Lett, 8, pp. 89-96, (2020); Westmoreland S.C., Evans R.F.L., Hrkac G., Schrel T., Zimanyi G.T., Winklhofer M., Sakuma N., Yano M., Kato A., Shoji T., Manabe A., Ito M., Chantrell R.W., Scr. Mater, 148, pp. 56-62, (2018); Westmoreland S.C., Skelland C., Shoji T., Yano M., Kato A., Ito M., Hrkac G., Schrefl T., Evans R.F.L., Chantrell R.W., J. Appl. Phys, 127, (2020)","M. Nishino; National Institute for Materials Science, Tsukuba, 305–0047, Japan; email: nishino.masamichi@nims.go.jp","","Japan Institute of Metals (JIM)","","","","","","00214876","","NIKGA","","Japanese","Nippon Kinzoku Gakkaishi","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85161516769" +"Dutta A.; Mukherjee P.; Sarangi S.P.; Bhattacharjee S.; Pal S.; Mondal R.","Dutta, Arpita (58790127900); Mukherjee, Pratyay (59357534200); Sarangi, Swosti P. (59358521400); Bhattacharjee, Somasree (59358721000); Pal, Shovon (56293102200); Mondal, Ritwik (56594584000)","58790127900; 59357534200; 59358521400; 59358721000; 56293102200; 56594584000","Role of material-dependent properties in THz field-derivative-torque-induced nonlinear magnetization dynamics","2024","Physical Review Materials","8","11","114404","","","","1","10.1103/PhysRevMaterials.8.114404","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85210289252&doi=10.1103%2fPhysRevMaterials.8.114404&partnerID=40&md5=6e376bcea8832be2d16a8866ddc8d2aa","School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Odisha, Jatni, 752 050, India; Department of Physics, Indian Institute of Technology (ISM) Dhanbad, Dhanbad, 826 004, India","Dutta A., School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Odisha, Jatni, 752 050, India; Mukherjee P., Department of Physics, Indian Institute of Technology (ISM) Dhanbad, Dhanbad, 826 004, India; Sarangi S.P., School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Odisha, Jatni, 752 050, India; Bhattacharjee S., Department of Physics, Indian Institute of Technology (ISM) Dhanbad, Dhanbad, 826 004, India; Pal S., School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Odisha, Jatni, 752 050, India; Mondal R., Department of Physics, Indian Institute of Technology (ISM) Dhanbad, Dhanbad, 826 004, India","The traditional Landau-Lifshitz-Gilbert (LLG) equation has often delineated the linear and nonlinear magnetization dynamics, even at ultrashort timescales, e.g., femtoseconds. In contrast, several other nonrelativistic and relativistic spin torques have been reported as an extension of the LLG spin dynamics. Here, we explore the contribution of the relativistic field-derivative torque (FDT) in the nonlinear THz magnetization dynamics response applied to ferrimagnets with high Gilbert damping and exchange magnon frequency. Our findings suggest that the FDT plays a significant role in magnetization dynamics in both linear and nonlinear regimes, bridging the gap between the traditional LLG spin dynamics and experimental observations. We find that the coherent THz magnon excitation amplitude is enhanced with the field-derivative torque. Furthermore, a phase shift in the oscillation of the Néel vector is induced by the FDT term. This phase shift is almost 90∘ for the antiferromagnet, while it is almost zero for the ferrimagnet under our investigation. Analyzing the dual THz excitation and their FDT, we find that the nonlinear signals can not be distinctly observed without the FDT terms. However, the inclusion of the FDT terms produces distinct nonlinear signals, which matches extremely well with the previously reported experimental results. © 2024 American Physical Society.","","Antiferromagnetism; Dynamics; Ferrimagnetism; Magnetization; Nonlinear equations; Ferrimagnets; Field derivatives; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Nonlinear magnetization dynamics; Nonlinear signals; Property; Relativistics; THz fields; Spin dynamics","","","","","Department of Atomic Energy, Government of India, DAE; National Institute of Science Education and Research, NISER; Basic Research in Physical and Multidisciplinary Sciences, (RIN4001); Science and Engineering Research Board, SERB, (SRG/2022/000290); Science and Engineering Research Board, SERB; SERB-SRG, (SRG/2023/000612, 196)/2023-2024/PHYSICS)","A.D. and S.P. acknowledge the support from DAE through the project Basic Research in Physical and Multidisciplinary Sciences via RIN4001. S.P. also acknowledges the startup support from DAE through NISER and SERB through SERB-SRG via Project No. SRG/2022/000290. R.M. acknowledges SERB-SRG via Project No. SRG/2023/000612 and the faculty research scheme at IIT (ISM) Dhanbad, India under Project No. FRS(196)/2023-2024/PHYSICS. The authors acknowledge C. Tzschaschel for the fruitful discussions.","Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Ultrafast spin dynamics in ferromagnetic nickel, Phys. Rev. Lett, 76, (1996); Stanciu C. D., Hansteen F., Kimel A. V., Kirilyuk A., Tsukamoto A., Itoh A., Rasing T., All-optical magnetic recording with circularly polarized light, Phys. Rev. Lett, 99, (2007); Kimel A. V., Kirilyuk A., Rasing T., Femtosecond opto-magnetism: ultrafast laser manipulation of magnetic materials, Laser Photon. 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A., Ando K., Saitoh E., Shimura T., Kuroda K., Directional control of spin-wave emission by spatially shaped light, Nat. Photon, 6, (2012); Parchenko S., Stupakiewicz A., Yoshimine I., Satoh T., Maziewski A., Wide frequencies range of spin excitations in a rare-earth Bi-doped iron garnet with a giant Faraday rotation, Appl. Phys. Lett, 103, (2013); Parchenko S., Tekielak M., Yoshimine I., Satoh T., Maziewski A., Stupakiewicz A., Magnetization reversal and magnetic domain structures in Gd-Yb-Big crystals, IEEE Tran. Magn, 50, (2014); Kittel C., Theory of ferromagnetic resonance in rare earth garnets. III. Giant anisotropy anomalies, Phys. Rev, 117, (1960); Kaplan J., Kittel C., Exchange frequency electron spin resonance in ferrites, J. Chem. Phys, 21, (1953); All the phase shift values are mapped to (Equation presented) and, thereafter, we take the absolute of these values to get the phase shift in the interval (Equation presented)","A. Dutta; School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Jatni, Odisha, 752 050, India; email: arpita.dutta@niser.ac.in; S. Pal; School of Physical Sciences, National Institute of Science Education and Research, An OCC of HBNI, Jatni, Odisha, 752 050, India; email: shovon.pal@niser.ac.in; R. Mondal; Department of Physics, Indian Institute of Technology (ISM) Dhanbad, Dhanbad, 826 004, India; email: ritwik@iitism.ac.in","","American Physical Society","","","","","","24759953","","","","English","Physic. Rev. Mat.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85210289252" +"Assouline B.; Capua A.","Assouline, Benjamin (55504596500); Capua, Amir (16300540000)","55504596500; 16300540000","On the generality of the LLG equation to the optical limit: An optically-induced helicity dependent torque emerging from the LLG equation","2023","Proceedings of SPIE - The International Society for Optical Engineering","12656","","126560R","","","","0","10.1117/12.2692228","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85176240713&doi=10.1117%2f12.2692228&partnerID=40&md5=af605b83bfcf3061a826a1994b1053c4","Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel","Assouline B., Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel; Capua A., Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel","It is well known that the Gilbert relaxation time of a magnetic moment scales inversely with the magnitude of the externally applied field, H, and the Gilbert damping, α. Therefore, in ultrashort optical pulses, where H can temporarily be large, the Gilbert relaxation time can momentarily be extremely short, reaching even picosecond timescales. Here we show that for typical ultrashort pulses, the magnetization can respond within the optical cycle such that the optical control of the magnetization emerges by merely considering the optical magnetic field in the Landau-Lifshitz-Gilbert (LLG) equation. Interestingly, when circularly polarized optical pulses are introduced to the LLG equation, an optically induced helicity-dependent torque results. We find that the strength of the interaction is determined by N = ayH/F""#, where fc!""# and yare the optical frequency and gyromagnetic ratio. Our results illustrate the generality of the LLG equation to the optical limit and the pivotal role of the Gilbert damping in the general interaction between optical magnetic fields and spins in solids. © 2023 SPIE.","all-optical magnetization switching; helicity dependent magnetization switching; Landau-Lifshitz-Gilbert equation; magneto-optics; ultrafast magnetization dynamics","Damping; Laser pulses; Magnetic fields; Magnetic moments; Magnetization; Spin dynamics; Yttrium aluminum garnet; All optical; All-optical magnetization switching; Helicities; Helicity dependent magnetization switching; Landau-Lifshitz-Gilbert equations; Magnetization switching; Optical limits; Optically induced; Ultrafast magnetization dynamics; Relaxation time","","","","","","","Stanciu C. D., Hansteen F., Kimel A. V., Kirilyuk A., Tsukamoto A., Itoh A., Rasing T., All-Optical Magnetic Recording with Circularly Polarized Light, Physical Review Letters, 99, (2007); Hohlfeld J., Stanciu C. D., Rebei A., Athermal all-optical femtosecond magnetization reversal in GdFeCo, Applied Physics Letters, 94, (2009); Steil D., Alebrand S., Hassdenteufel A., Cinchetti M., Aeschlimann M., All-optical magnetization recording by tailoring optical excitation parameters, Physical Review B, 84, (2011); Zhang G. P., Latta T., Babyak Z., Bai Y. H., George T. F., All-optical spin switching: A new frontier in femtomagnetism — A short review and a simple theory, Modern Physics Letters B, 30, (2016); Bigot J.-Y., Vomir M., Ultrafast magnetization dynamics of nanostructures, Annalen der Physik, 525, (2013); Kirilyuk A., Kimel A. V., Rasing T., Ultrafast optical manipulation of magnetic order, Reviews of Modern Physics, 82, (2010); Vahaplar K., Kalashnikova A. M., Kimel A. V., Gerlach S., Hinzke D., Nowak U., Chantrell R., Tsukamoto A., Itoh A., Kirilyuk A., Rasing T., All-optical magnetization reversal by circularly polarized laser pulses: Experiment and multiscale modeling, Physical Review B, 85, (2012); Alebrand S., Gottwald M., Hehn M., Steil D., Cinchetti M., Lacour D., Fullerton E. E., Aeschlimann M., Mangin S., Light-induced magnetization reversal of high-anisotropy TbCo alloy films, Applied Physics Letters, 101, (2012); Hassdenteufel A., Hebler B., Schubert C., Liebig A., Teich M., Helm M., Aeschlimann M., Albrecht M., Bratschitsch R., Thermally Assisted All-Optical Helicity Dependent Magnetic Switching in Amorphous Fe100–xTbx Alloy Films, Advanced Materials, 25, (2013); Mangin S., Gottwald M., Lambert C. H., Steil D., Uhlir V., Pang L., Hehn M., Alebrand S., Cinchetti M., Malinowski G., Fainman Y., Aeschlimann M., Fullerton E. E., Engineered materials for all-optical helicity-dependent magnetic switching, Nature Materials, 13, (2014); Lambert C.-H., Mangin S., Varaprasad B. S. D. C. S., Takahashi Y. K., Hehn M., Cinchetti M., Malinowski G., Hono K., Fainman Y., Aeschlimann M., Fullerton E. E., All-optical control of ferromagnetic thin films and nanostructures, Science, 345, (2014); Ellis M. O. A., Fullerton E. E., Chantrell R. W., All-optical switching in granular ferromagnets caused by magnetic circular dichroism, Scientific Reports, 6, (2016); Vahaplar K., Kalashnikova A. M., Kimel A. V., Hinzke D., Nowak U., Chantrell R., Tsukamoto A., Itoh A., Kirilyuk A., Rasing T., Ultrafast Path for Optical Magnetization Reversal via a Strongly Nonequilibrium State, Physical Review Letters, 103, (2009); Nemec P., Rozkotova E., Tesarova N., Trojanek F., De Ranieri E., Olejnik K., Zemen J., Novak V., Cukr M., Maly P., Jungwirth T., Experimental observation of the optical spin transfer torque, Nature Physics, 8, (2012); Choi G.-M., Schleife A., Cahill D. G., Optical-helicity-driven magnetization dynamics in metallic ferromagnets, Nature Communications, 8, (2017); Boeglin C., Beaurepaire E., Halte V., Lopez-Flores V., Stamm C., Pontius N., Durr H. A., Bigot J. Y., Distinguishing the ultrafast dynamics of spin and orbital moments in solids, Nature, 465, (2010); Mueller B. Y., Roth T., Cinchetti M., Aeschlimann M., Rethfeld B., Driving force of ultrafast magnetization dynamics, New Journal of Physics, 13, (2011); Koopmans B., Ruigrok J. J. M., Longa F. D., de Jonge W. J. M., Unifying Ultrafast Magnetization Dynamics, Physical Review Letters, 95, (2005); Koopmans B., Malinowski G., Dalla Longa F., Steiauf D., Fahnle M., Roth T., Cinchetti M., Aeschlimann M., Explaining the paradoxical diversity of ultrafast laser-induced demagnetization, Nature Materials, 9, (2010); Wang C., Liu Y., Ultrafast optical manipulation of magnetic order in ferromagnetic materials, Nano Convergence, 7, (2020); Capua A., Karni O., Eisenstein G., Sichkovskyi V., Ivanov V., Reithmaier J. P., Coherent control in a semiconductor optical amplifier operating at room temperature, Nature Communications, 5, (2014); Capua A., Karni O., Eisenstein G., Reithmaier J. P., Rabi oscillations in a room-temperature quantum dash semiconductor optical amplifier, Physical Review B, 90, (2014); Feynman R. P., Vernon F. L., Hellwarth R. W., Geometrical Representation of the Schrödinger Equation for Solving Maser Problems, Journal of Applied Physics, 28, (1957); Scully M. O., Zubairy M. S., Quantum Optics, (1997); Gurevich Alexander G., Melkov G. A., Magnetization Oscillations and Waves, (1996); Allen L., Eberly J., Optical Resonance and Two Level Atoms, (1987); Yao J., Agrawal G. P., Gallion P., Bowden C. M., Semiconductor laser dynamics beyond the rate-equation approximation, Optics Communications, 119, (1995); Capua A., Rettner C., Yang S.-H., Phung T., Parkin S. S. P., Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film, Nature Commun, 8, (2017); Fujita N., Inaba N., Kirino F., Igarashi S., Koike K., Kato H., Damping constant of Co/Pt multilayer thin-film media, Journal of Magnetism and Magnetic Materials, 320, (2008); Morrish A. H., The Physical Principles of Magnetism, (2001)","A. Capua; Institute of Electrical Engineering and Applied Physics, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel; email: amir.capua@mail.huji.ac.il","Wegrowe J.-E.; Friedman J.S.; Razeghi M.","SPIE","The Society of Photo-Optical Instrumentation Engineers (SPIE)","Spintronics XVI 2023","20 August 2023 through 24 August 2023","San Diego","193401","0277786X","978-151066526-2","PSISD","","English","Proc SPIE Int Soc Opt Eng","Conference paper","Final","","Scopus","2-s2.0-85176240713" +"Verstraten R.C.; Ludwig T.; Duine R.A.; Morais Smith C.","Verstraten, R.C. (57219741000); Ludwig, T. (57213497955); Duine, R.A. (6603233535); Morais Smith, C. (8909666700)","57219741000; 57213497955; 6603233535; 8909666700","Fractional Landau-Lifshitz-Gilbert equation","2023","Physical Review Research","5","3","033128","","","","5","10.1103/PhysRevResearch.5.033128","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85169298734&doi=10.1103%2fPhysRevResearch.5.033128&partnerID=40&md5=6e98ea47d56df317ba8e4ea67884b6a7","Institute for Theoretical Physics, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands; Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB, Netherlands","Verstraten R.C., Institute for Theoretical Physics, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands; Ludwig T., Institute for Theoretical Physics, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands; Duine R.A., Institute for Theoretical Physics, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB, Netherlands; Morais Smith C., Institute for Theoretical Physics, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands","The dynamics of a magnetic moment or spin are of high interest to applications in technology. Dissipation in these systems is therefore of importance for improvement of efficiency of devices, such as the ones proposed in spintronics. A large spin in a magnetic field is widely assumed to be described by the Landau-Lifshitz-Gilbert (LLG) equation, which includes a phenomenological Gilbert damping. Here, we couple a large spin to a bath and derive a generic (non-)Ohmic damping term for the low-frequency range using a Caldeira-Leggett model. This leads to a fractional LLG equation, where the first-order derivative Gilbert damping is replaced by a fractional derivative of order sϵR≥0. We show that the parameter s can be determined from a ferromagnetic resonance experiment, where the resonance frequency and linewidth no longer scale linearly with the effective field strength. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.","","Damping; Spin dynamics; Caldeira-Leggett model; Damping terms; First-order derivative; Fractional derivatives; Gilbert damping; Landau-Lifshitz-Gilbert equations; Large spin; Low frequency range; Magnetic-field; Ohmic damping; Magnetic moments","","","","","Nederlandse Organisatie voor Wetenschappelijk Onderzoek, NWO, (182.069, 680.92.18.05)","This work was supported by the Netherlands Organization for Scientific Research (NWO, Grant No. 680.92.18.05, C.M.S. and R.C.V., and (partly) NWO, Grant No. 182.069, T.L. and R.A.D.).","Mayergoyz I. D., Bertotti G., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Harder M., Gui Y., Hu C.-M., Electrical detection of magnetization dynamics via spin rectification effects, Phys. Rep, 661, (2016); Barman A., Mondal S., Sahoo S., De A., Magnetization dynamics of nanoscale magnetic materials: A perspective, J. Appl. Phys, 128, (2020); Chudnovsky E. M., Iglesias O., Stamp P. C. E., Quantum tunneling of domain walls in ferromagnets, Phys. Rev. B, 46, (1992); Garg A., Kim G.-H., Dissipation in Macroscopic Magnetization Tunneling, Phys. Rev. Lett, 63, (1989); Kim S. K., Tchernyshyov O., Galitski V., Tserkovnyak Y., Magnon-induced non-Markovian friction of a domain wall in a ferromagnet, Phys. Rev. B, 97, (2018); Psaroudaki C., Loss D., Skyrmions Driven by Intrinsic Magnons, Phys. Rev. Lett, 120, (2018); Psaroudaki C., Aseev P., Loss D., Quantum Brownian motion of a magnetic skyrmion, Phys. Rev. B, 100, (2019); Guo Z., Yin J., Bai Y., Zhu D., Shi K., Wang G., Cao K., Zhao W., Spintronics for energy-efficient computing: An overview and outlook, Proc. IEEE, 109, (2021); Lakshmanan M., The fascinating world of the landau-lifshitz-gilbert equation: an overview, Philos. Trans. R. Soc. A, 369, (2011); Awschalom D. D., Flatte M. E., Challenges for semiconductor spintronics, Nat. Phys, 3, (2007); Koopmans B., Ruigrok J. J. M., Dalla Longa F., de Jonge W. J. M., Unifying Ultrafast Magnetization Dynamics, Phys. Rev. Lett, 95, (2005); Duine R. A., Nunez A. S., Sinova J., MacDonald A. H., Functional Keldysh theory of spin torques, Phys. Rev. B, 75, (2007); Anders J., Sait C. R., Horsley S. A., Quantum Brownian motion for magnets, New J. Phys, 24, (2022); Caldeira A. O., Leggett A. J., Influence of Dissipation on Quantum Tunneling in Macroscopic Systems, Phys. Rev. Lett, 46, (1981); Caldeira A. O., Leggett A. J., Path integral approach to quantum Brownian motion, Physica A, 121, (1983); Caldeira A. O., Leggett A. J., Quantum tunnelling in a dissipative system, Ann. Phys. (NY), 149, (1983); Caldeira A. 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Phys, 29, (1966); The dissipation kernel (Equation presented) is closely related to the retarded (Equation presented) and advanced (Equation presented) components; Tserkovnyak Y., Brataas A., Bauer G. E. W., Enhanced Gilbert Damping in Thin Ferromagnetic Films, Phys. Rev. Lett, 88, (2002); This definition does not have any boundary conditions, as they would have to be at (Equation presented) and would dissipate before reaching a finite time. One can, however, enforce boundary conditions by applying a very strong magnetic field for some time, such that the spin aligns itself and then quickly changes to the desired field at (Equation presented); Dubkov A. A., Spagnolo B., Uchaikin V. V., Lévy flight superdiffusion: an introduction, Int. J. Bifurcat. Chaos, 18, (2008); Ludwig T., Burmistrov I. S., Gefen Y., Shnirman A., Current noise geometrically generated by a driven magnet, Phys. Rev. Res, 2, (2020); Schmid A., On a quasiclassical langevin equation, J. Low Temp. Phys, 49, (1982); We use the convention (Equation presented) and (Equation presented); Gradshteyn I. S., Ryzhik I. M., Table of Integrals, Series, and Products, (2014)","","","American Physical Society","","","","","","26431564","","","","English","Phys. Rev. Res.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85169298734" +"Garcia-Gaitan F.; Kefayati A.; Xiao J.Q.; Nikolić B.K.","Garcia-Gaitan, Federico (58180449100); Kefayati, Ali (57217957515); Xiao, John Q. (7402564374); Nikolić, Branislav K. (7006055333)","58180449100; 57217957515; 7402564374; 7006055333","Magnon spectrum of altermagnets beyond linear spin wave theory: Magnon-magnon interactions via time-dependent matrix product states versus atomistic spin dynamics","2025","Physical Review B","111","2","L020407","","","","1","10.1103/PhysRevB.111.L020407","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85215300672&doi=10.1103%2fPhysRevB.111.L020407&partnerID=40&md5=bc69527a03ff40269e9867cec23de4f0","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Garcia-Gaitan F., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Kefayati A., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Xiao J.Q., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","The energy-momentum dispersion of magnons, as collective low-energy excitations of a magnetic material, is routinely computed from an effective quantum spin Hamiltonian but simplified via linearized Holstein-Primakoff transformations to describe noninteracting magnons. The dispersion produced by such linear spin wave theory (LSWT) is then plotted as ""sharp bands""of infinitely long-lived quasiparticles. However, magnons are prone to many-body interactions with other quasiparticles - such as electrons, phonons, and other magnons - which can lead to shifting (i.e., band renormalization) and broadening of the sharp bands as a signature of a finite quasiparticle lifetime. The magnon-magnon interactions can be particularly important in antiferromagnets, and, therefore, possibly in newly classified altermagnets sharing many features of collinear antiferromagnets. Here, we employ nonperturbative quantum many-body calculations via time-dependent matrix product states (TDMPSs) to obtain the magnon spectral function for a RuO2 altermagnet whose effective quantum spin Hamiltonian is put onto a four-leg cylinder. Its upper band is shifted away from the upper sharp band of LSWT, as well as broadened, which is explained as the consequence of hybridization of the latter with the three-magnon continuum. This implies that two-magnon Raman scattering spectra cannot be computed from LSWT bands, which offers a litmus test for the relevance of magnon-magnon interactions. Finally, we employ atomistic spin dynamics (ASD) simulations based on the classical Landau-Lifshitz-Gilbert (LLG) equation to obtain the magnon spectrum at finite temperature and/or at a fraction of the cost of TDMPS calculations. Despite including magnon-magnon interactions via the nonlinearity of the LLG equation, ASD simulations cannot match the TDMPS-computed magnon spectrum, thereby signaling nonclassical effects harbored by antiferromagnets and altermagnets. © 2025 American Physical Society.","","Antiferromagnetic materials; Antiferromagnetism; Continuum mechanics; Dispersion (waves); Dispersions; Linear transformations; Matrix algebra; Nanocrystals; Nonlinear equations; Ruthenium compounds; Spin dynamics; Spin waves; Statistical mechanics; Atomistics; Linear spin-wave theory; Magnon interactions; Magnon spectrum; Magnons; Matrix product state; Quantum spin; Quasiparticles; Spin hamiltonian; Time dependent; Hamiltonians","","","","","","","Kaxiras E., Joannopoulos J. D., Quantum Theory of Materials, (2019); Konschuh S., Gmitra M., Fabian J., Tight-binding theory of the spin-orbit coupling in graphene, Phys. Rev. B, 82, (2010); Kogan E., Nazarov V. U., Silkin V. 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B, 88, (2013); Note that recent experimental [79] and theoretical [80] scrutiny found (Equation presented) to be actually nonmagnetic in bulk form, but it remains an altermagnetic metal in the few-atomic-layer form [81]. Thus, these developments do not affect our study focused on just a single layer in Fig. 2, as well as on the general procedure for handling magnon-magnon interactions which can be applied to analyze a thereby induced modification of chiral magnon bands of other experimentally confirmed [82] altermagnetic materials; Smejkal L., Sinova J., Jungwirth T., Emerging research landscape of altermagnetism, Phys. Rev. X, 12, (2022); Smejkal L., Sinova J., Jungwirth T., Beyond conventional ferromagnetism and antiferromagnetism: A phase with nonrelativistic spin and crystal rotation symmetry, Phys. Rev. X, 12, (2022); Hayami S., Yanagi Y., Kusunose H., Momentum-dependent spin splitting by collinear antiferromagnetic ordering, J. Phys. Soc. 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M., Lake B., Nagler S. E., Granroth G. E., Okamoto S., Alvarez G., Tennant D. A., Witnessing entanglement in quantum magnets using neutron scattering, Phys. Rev. B, 103, (2021); Devereaux T. P., Hackl R., Inelastic light scattering from correlated electrons, Rev. Mod. Phys, 79, (2007); Lemmens P., Guntherodt G., Gros C., Magnetic light scattering in low-dimensional quantum spin systems, Phys. Rep, 375, (2003); Fleury P. A., Loudon R., Scattering of light by one-and two-magnon excitations, Phys. Rev, 166, (1968); Cottam M., Theory of two-magnon Raman scattering in antiferromagnets at finite temperatures, J. Phys. C, 5, (1972); Hutchings M. T., Thorpe M. F., Birgeneau R. J., Fleury P. A., Guggenheim H. J., Neutron and optical investigation of magnons and magnon-magnon interaction effects in (Equation presented), Phys. Rev. B, 2, (1970); Davies R. W., Chinn S. R., Zeiger H. J., Spin-wave approach to two-magnon Raman scattering in a simple antiferromagnet, Phys. Rev. B, 4, (1971); Hiraishi M., Okabe H., Koda A., Kadono R., Muroi T., Hirai D., Hiroi Z., Nonmagnetic ground state in (Equation presented) revealed by muon spin rotation, Phys. Rev. Lett, 132, (2024); Smolyanyuk A., Mazin I. I., Garcia-Gassull L., Valenti R., Fragility of the magnetic order in the prototypical altermagnet (Equation presented), Phys. Rev. B, 109, (2024); Jeong S. G., Choi I. H., Nair S., Buiarelli L., Pourbahari B., Oh J. Y., Bassim N., Seo A., Choi W. S., Fernandes R. M., Birol T., Zhao L., Lee J. S., Jalan B., Altermagnetic polar metallic phase in ultra-thin epitaxially-strained (Equation presented) films; Liu Z., Ozeki M., Asai S., Itoh S., Masuda T., Chiral split magnon in altermagnetic MnTe, Phys. Rev. Lett, 133, (2024); Berlijn T., Snijders P. C., Delaire O., Zhou H.-D., Maier T. A., Cao H.-B., Chi S.-X., Matsuda M., Wang Y., Koehler M. R., Kent P. R. C., Weitering H. H., Itinerant antiferromagnetism in (Equation presented), Phys. Rev. Lett, 118, (2017); Sugiura S., Shimizu A., Thermal pure quantum states at finite temperature, Phys. Rev. Lett, 108, (2012); Sugiura S., Shimizu A., Canonical thermal pure quantum state, Phys. Rev. Lett, 111, (2013); Gao Y., Wang J., Li Q., Yan Q.-B., Shi T., Li W., Magnon damping minimum and logarithmic scaling in a Kondo-Heisenberg model; Yan S., Huse D. A., White S. R., Spin-liquid ground state of the S = 1/2 kagome Heisenberg antiferromagnet, Science, 332, (2011); Press W. H., Teukolsky S. A., Vetterling W. T., Flannery B. P., Numerical Recipes: The Art of Scientific Computing, (2007); dos Santos F. J., dos Santos Dias M., Guimaraes F. S. M., Bouaziz J., Lounis S., Spin-resolved inelastic electron scattering by spin waves in noncollinear magnets, Phys. Rev. B, 97, (2018)","B.K. Nikolić; Department of Physics and Astronomy, University of Delaware, Newark, 19716, United States; email: bnikolic@udel.edu","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85215300672" +"Dulal S.; Sohid S.B.; Cui H.; Gu G.; Costinett D.J.; Tolbert L.M.","Dulal, Saurav (58656117900); Sohid, Sadia Binte (57205400665); Cui, Han (55774086800); Gu, Gong (36741471800); Costinett, Daniel J. (35147709500); Tolbert, Leon M. (7102144014)","58656117900; 57205400665; 55774086800; 36741471800; 35147709500; 7102144014","A Physics-Based Circuit Model for Nonlinear Magnetic Material Characteristics","2024","Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC","","","","396","401","5","0","10.1109/APEC48139.2024.10509097","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85192769047&doi=10.1109%2fAPEC48139.2024.10509097&partnerID=40&md5=2dad95aee5ab73361f0e3576794c71fa","The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States","Dulal S., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States; Sohid S.B., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States; Cui H., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States; Gu G., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States; Costinett D.J., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States; Tolbert L.M., The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, TN, United States","Nonlinear magnetic properties in power electronics applications, such as permeability and core loss cause significant discrepancies between magnetic designs and prototype measurements, leading to iterative prototyping efforts. To address this issue, a bottom-up approach that is based on the physics of magnetic material is proposed to unveil the fundamental origin of nonlinearity. The physical parameters such as magnetization, gyromagnetic ratio, damping factor, etc., are translated to equivalent circuit parameters. The nonlinear magnetization dynamics of a single magnetic domain are described by an equivalent circuit model derived from the Landau-Lifshitz-Gilbert (LLG) equation. A fictitious magnetic domain is used to demonstrate the developed model's capability on predicting the nonlinearity that includes magnetization dynamics and hysteresis. Then, the model is further validated by a commercial material, TDK N87 toroidal core. The results such as B-H loop and permeability simulated from the circuit model are in close agreement with the datasheet, validating the feasibility of predicting magnetic material's nonlinear performance from physics perspective rather than empirical approaches. © 2024 IEEE.","hysteresis; magnetic modeling; nonlinear; single domain","Circuit simulation; Equivalent circuits; Magnetic circuits; Magnetic domains; Magnetic materials; Magnetization; Nonlinear equations; Timing circuits; Core loss; Magnetic models; Material characteristics; Nonlinear; Nonlinear magnetic materials; Nonlinear magnetic properties; Permeability loss; Physics-based circuit models; Power electronic applications; Single domains; Hysteresis","","","","","Office of Naval Research, ONR, (N00014-22-1-2545); Office of Naval Research, ONR","The Office of Naval Research provided funding for this project through Grant Award No. N00014-22-1-2545, \""A multiscale physic-based magnetics design framework for ship scale power electronics.\""","Hanson J., Belk J.A., Lim S., Sullivan C.R., Perreault D.J., Measurements and performance factor comparisons of magnetic materials at high frequency, IEEE Transactions on Power Electronics, 31, 11, pp. 7909-7925, (2016); Han Y., Cheung G., Li A., Sullivan C.R., Perreault D.J., Evaluation of magnetic materials for very high frequency power applications, IEEE Transactions on Power Electronics, 27, 1, pp. 425-435, (2011); Ohodnicki P., Emergence of WBG based power electronics and system level needs / opportunities for advances in passives, packaging, and peripherals with emphasis on HF magnetics; Ferrites and Accessories: SIFERRIT material N87 datasheet, TDK, (2023); Cui H., Dulal S., Sohid S.B., Gu G., Tolbert L.M., Unveiling the Microworld Inside Magnetic Materials via Circuit Models, IEEE Power Electronics Magazine, 10, 3, pp. 14-22, (2023); Muhlethaler J., Biela J., Kolar J.W., Ecklebe A., Core losses under the DC bias condition based on Steinmetz parameters, IEEE Trans. Power Electron., 27, 2, pp. 953-963, (2012); Mu M., Li Q., Gilham D.J., Lee F.C., Ngo K.D.T., New core loss measurement method for high-frequency magnetic materials, IEEE Trans. Power Electron., 29, 8, pp. 4374-4381, (2014); Jiles D.C., Atherton D.L., Theory of ferromagnetic hysteresis, Journal of magnetism and magnetic materials, 61, 1-2, pp. 48-60, (1986); Mayergoyz I., Mayergoyz I., The classical Preisach model of hysteresis, Mathematical models of hysteresis, pp. 1-63, (1991); Chen M., How MagNet: Machine Learning Framework for Modeling Power Magnetic Material Characteristics, TechRxiv. Preprint., (2022); Chen M., Why MagNet: Quantifying the Complexity of Modeling Power Magnetic Material Characteristics, TechRxiv. Preprint., (2022); Lakshmanan M., The fascinating world of the Landau-Lifshitz-Gilbert equation: An overview, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 369, 1939, pp. 1280-1300, (2011); Gao Q., Fordham M.E., Gu W., Cui H., Wang Y.E., Design RF Magnetic Devices With Linear and Nonlinear Equivalent Circuit Models: Demystify RF Magnetics With Equivalent Circuit Models, IEEE Microwave Magazine, 23, 11, pp. 28-47, (2022); Pozar D.M., Microwave Engineering, (2011); Coey J.M., Magnetism and Magnetic Materials, (2010); Nowak U., Classical Spin Models, Handbook of Magnetism and Advanced Magnetic Materials, (2007); Aziz M.M., Sub-Nanosecond Electromagnetic-Micromagnetic Dynamic Simulations Using the Finite-Difference Time-Domain Method, Progress In Electromagnetics Research B, 15, pp. 1-29, (2009); TDK Electronics: Ferrite Magnetic Design Tool ver. 5. 6. 1, (2022)","S. Dulal; The University of Tennessee, Department of Electrical Engineering and Computer Science, Knoxville, United States; email: sdulal@vols.utk.edu","","Institute of Electrical and Electronics Engineers Inc.","IEEE Industry Applications Society (IAS); IEEE Power Electronics Society (PELS); Power Sources Manufacturers Association (PSMA)","39th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2024","25 February 2024 through 29 February 2024","Long Beach","199264","10482334","979-835031664-3","CPAEE","","English","Conf Proc IEEE Appl Power Electron Conf Expo APEC","Conference paper","Final","","Scopus","2-s2.0-85192769047" +"Fang Z.; Wang X.","Fang, Zheyue (59174134300); Wang, Xiaoping (56382555600)","59174134300; 56382555600","An Adaptive Moving Mesh Method for Simulating Finite-Time Blowup Solutions of the Landau-Lifshitz -Gilbert Equation","2024","East Asian Journal on Applied Mathematics","14","3","","601","635","34","0","10.4208/eajam.2023-322.250224","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85196071290&doi=10.4208%2feajam.2023-322.250224&partnerID=40&md5=ed450eb03cd6b4330fee7ae070a16ec8","Department of Mathematics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; School of Science and Engineering, Chinese Univ. of Hong Kong, Shenzhen, 518172, China; Shenzhen International Center for Industrial and Applied Mathematics, Shenzhen Research Institute of Big Data, Shenzhen, 518172, China","Fang Z., Department of Mathematics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Wang X., School of Science and Engineering, Chinese Univ. of Hong Kong, Shenzhen, 518172, China, Shenzhen International Center for Industrial and Applied Mathematics, Shenzhen Research Institute of Big Data, Shenzhen, 518172, China","We present a moving mesh finite element method to study the finite-time blowup solution of the Landau-Lifshitz-Gilbert (LLG) equation, considering both the heat flow of harmonic map and the full LLG equation. Our approach combines projection methods for solving the LLG equation with an iterative grid redistribution method to generate adaptive meshes. Through iterative remeshing, we successfully simulate blowup solutions with maximum gradient magnitudes up to 104 and minimum mesh sizes of 10−5. We investigate the self-similar patterns and blowup rates of these solutions, and validate our numerical findings by comparing them to established analytical results from a recent study. © 2024 Global-Science Press.","adaptive mesh; blowup solution; Landau-Lifshitz-Gilbert equation","","","","","","National Natural Science Foundation of China, NSFC, (12271461, 12131010); Chinese University of Hong Kong, CUHK, (UDF01002028); Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Project, (HZQSWS-KCCYB-2024016)","X.-P. Wang acknowledges support from National Natural Science Foundation of China (No. 12271461), the key project of NSFC (No. 12131010), the University Development Fund from The Chinese University of Hong Kong, Shenzhen (No. UDF01002028), and Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Project (No. HZQSWS-KCCYB-2024016).","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Brackbill J.U., Saltzman J.S., Adaptive zoning for singular problems in two dimensions, J. Comput. Phys, 46, pp. 342-368, (1982); Brown W.F., Micromagnetics, (1963); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in R3, Commun. Appl. Anal, 5, pp. 17-30, (2001); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in a bounded domain, Differential Integral Equations, 14, pp. 213-229, (2001); Chang K.-C., Heat flow and boundary value problem for harmonic maps, Ann. Henri Poincaré, 6, pp. 363-395, (1989); Chen Y., Lin F.H., Evolution of harmonic maps with Dirichlet boundary conditions, Commun. Anal. Geom, 1, pp. 327-346, (1993); Chen Y., Struwe M., Existence and partial regularity results for the heat flow for harmonic maps, Math. Z, 201, pp. 83-103, (1989); Coron J.-M., Nonuniqueness for the heat flow of harmonic maps, Ann. Henri Poincaré, 7, pp. 335-344, (1990); Di Y., Li R., Tang T., Zhang P., Moving mesh finite element methods for the incompressible Navier-Stokes equations, SIAM J. Sci. Comput, 26, pp. 1036-1056, (2005); Dvinsky A.S., Adaptive grid generation from harmonic maps on Riemannian manifolds, J. Comput. Phys, 95, pp. 450-476, (1991); Wang X.-P., Numerical methods for the Landau-Lifshitz equation, SIAM J. Numer. Anal, pp. 1647-1665, (2001); Freire A., Uniqueness for the harmonic map flow from surface to general targets, Comment. Math. Helv, 2, pp. 310-338, (1995); Freire A., Uniqueness for the harmonic map flow in two dimensions, Calc. Var. Partial Differential Equations, 3, pp. 95-105, (1995); Guo B., Hong M.-C., The Landau-Lifshitz equation of the ferromagnetic spin chain and harmonic maps, Calc. Var. Partial Differential Equations, 1, pp. 311-334, (1993); Huang W., Variational mesh adaptation: Isotropy and equidistribution, J. Comput. Phys, 174, pp. 903-924, (2001); Huang W., Kamenski L., A geometric discretization and a simple implementation for variational mesh generation and adaptation, J. Comput. Phys, 301, pp. 322-337, (2015); Huang W., Russell R.D., Moving mesh strategy based on a gradient flow equation for two-dimensional problems, SIAM J. Sci. Comput, 20, pp. 998-1015, (1998); Huang W., Zheng L., Zhan X., Adaptive moving mesh methods for simulating one-dimensional groundwater problems with sharp moving fronts, Internat. J. Numer. Methods Engrg, 54, pp. 1579-1603, (2002); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Perspectives in Theoretical Physics, pp. 51-65, (1992); Li R., Tang T., Zhang P., Moving mesh methods in multiple dimensions based on harmonic maps, J. Comput. Phys, 170, pp. 562-588, (2001); Liao G., Liu F., Pena G.C., Peng D., Osher S., Level-set-based deformation methods for adaptive grids, J. Comput. Phys, 159, pp. 103-122, (2000); Passo R., Hout R., Nonuniqueness for the heat flow of harmonic maps on the disk, Arch. Ration. Mech. Anal, 161, pp. 93-112, (2002); Ren W., Wang X.-P., An iterative grid redistribution method for singular problems in multiple dimensions, J. Comput. Phys, 159, pp. 246-273, (2000); Stockie J.M., Mackenzie J.A., Russell R.D., A moving mesh method for one-dimensional hyperbolic conservation laws, SIAM J. Sci. Comput, 22, pp. 1791-1813, (2001); Struwe M., On the evolution of harmonic mappings of Riemannian surfaces, Comment. Math. Helv, 60, pp. 558-581, (1985); Struwe M., On the evolution of harmonic maps in higher dimensions, J.Differential Geom, 28, pp. 485-502, (1988); Tukovic Z., Jasak H., A moving mesh finite volume interface tracking method for surface tension dominated interfacial fluid flow, Comput. & Fluids, 55, pp. 70-84, (2012); Wang X.-P., Garcia-Cervera C.J., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, pp. 357-372, (2001); Wei J., Zhang Q., Zhou Y., Finite-time singularity formations for the Landau-Lifshitz-Gilbert equation in dimension two, (2022); Winslow A.M., Numerical solution of the quasilinear poisson equation in a nonuniform triangle mesh, J. Comput. Phys, 1, pp. 149-172, (1966)","Z. Fang; Department of Mathematics, Hong Kong University of Science and Technology, Kowloon, Clear Water Bay, Hong Kong; email: zfangaf@connect.ust.hk; X. Wang; School of Science and Engineering, Chinese Univ. of Hong Kong, Shenzhen, 518172, China; email: wangxiaoping@cuhk.edu.cn","","Global Science Press","","","","","","20797362","","","","English","East Asian J. Appl. Math.","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85196071290" +"Dong H.M.; Fu P.P.; Duan Y.F.; Chang K.","Dong, H.M. (55905250200); Fu, P.P. (58629544000); Duan, Y.F. (23389269500); Chang, K. (7404878383)","55905250200; 58629544000; 23389269500; 7404878383","Tuning nano-skyrmions and nano-skyrmioniums in Janus magnets","2023","Nanoscale","15","38","","15643","15648","5","3","10.1039/d3nr02181e","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85172994786&doi=10.1039%2fd3nr02181e&partnerID=40&md5=9d2da78227b73939027a6c389d088898","School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China; SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083, China","Dong H.M., School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China; Fu P.P., School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China; Duan Y.F., School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China; Chang K., SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083, China","We study non-trivial spin textures, nanoscale magnetic skyrmions and skyrmioniums, in two-dimensional (2D) Janus magnets, such as MnSTe and MnSeTe, based on the micromagnetism approach and Landau-Lifshitz-Gilbert (LLG) equation. It is found that the Janus magnetic structures can host stable Néel nano-skyrmions with sub-10 nm diameters, and skyrmioniums with zero topological charge. The skyrmion size can be squeezed by external magnetic fields, and even the topological charge can be changed. The diameters of the skyrmioniums are about twice the size of the skyrmions. Moreover, the switching of the topological charge Q = ±1 can be realized by changing the direction of the external magnetic fields. Our results clearly show that magnetic skyrmions in Janus magnets can be used to construct new types of efficient spintronic nanodevices. © 2023 The Royal Society of Chemistry.","","Magnetic fields; Nanomagnetics; Selenium compounds; Sulfur compounds; Tellurium compounds; Textures; Topology; External magnetic field; Landau-Lifshitz-Gilbert equations; Micromagnetisms; Nano scale; Non-trivial; Skyrmions; Spin textures; Sub 10 nm; Topological charges; Two-dimensional; Manganese compounds","","","","","Key Academic Discipline Project of China University of Mining and Technology, (2022WLXK03); National Natural Science Foundation of China, NSFC, (12374079)","This work is supported by the Key Academic Discipline Project of China University of Mining and Technology (No. 2022WLXK03) and by the National Natural Science Foundation of China (Grant No. 12374079).","Reichhardt C., Reichhardt C.J.O., Milosevic M.V., Rev. Mod. 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Matter, 32, (2020); Yuan J., Yang Y., Cai Y., Wu Y., Chen Y., Yan X., Shen L., Phys. Rev. B, 101, (2020); Xu C., Chen P., Tan H., Yang Y., Xiang H., Bellaiche L., Phys. Rev. Lett., 125, (2020); Gilbert T., IEEE Trans. Magn., 40, (2004); Romming N., Kubetzka A., Hanneken C., von Bergmann K., Wiesendanger R., Phys. Rev. Lett., 114, (2015); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., AIP Adv., 4, (2014); Mulkers J., Van Waeyenberge B., Milosevic M.V., Phys. Rev. B, 95, (2017); Koshibae W., Nagaosa N., Nat. Commun., 7, (2016); Behera A.K., Chowdhury S., Das S.R., Appl. Phys. Lett., 114, (2019); Zhang X., Xia J., Zhou Y., Wang D., Liu X., Zhao W., Ezawa M., Phys. Rev. B: Condens. Matter Mater. Phys., 94, (2016); Kovalev A.A., Sandhoefner S., Front. Phys., 6, (2018); Zhang S., Kronast F., van der Laan G., Hesjedal T., Nano Lett., 18, (2018); Muller G.P., Hoffmann M., Disselkamp C., Schurhoff D., Mavros S., Sallermann M., Kiselev N.S., Jonsson H., Blugel S., Phys. Rev. B, 99, (2019)","H.M. Dong; School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, 221116, China; email: hmdong@cumt.edu.cn; K. Chang; SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, P.O. Box 912, 100083, China; email: kchang@semi.ac.cn","","Royal Society of Chemistry","","","","","","20403364","","","","English","Nanoscale","Article","Final","","Scopus","2-s2.0-85172994786" +"Sun Y.; Chen J.; Du R.; Wang C.","Sun, Yifei (57224921534); Chen, Jingrun (57219146828); Du, Rui (56763448500); Wang, Cheng (57192604518)","57224921534; 57219146828; 56763448500; 57192604518","ADVANTAGES OF A SEMI-IMPLICIT SCHEME OVER A FULLY IMPLICIT SCHEME FOR LANDAU-LIFSHITZ-GILBERT EQUATION","2023","Discrete and Continuous Dynamical Systems - Series B","28","9","","5105","5122","17","0","10.3934/dcdsb.2023057","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85159373039&doi=10.3934%2fdcdsb.2023057&partnerID=40&md5=d2ff0700a691f7c52edceff0f5df4790","School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; Mathematics Department, University of Massachusetts, North Dartmouth, 02747, MA, United States","Sun Y., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Chen J., School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China, Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; Du R., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; Wang C., Mathematics Department, University of Massachusetts, North Dartmouth, 02747, MA, United States","Magnetization dynamics in magnetic materials is modeled by the Landau-Lifshitz-Gilbert (LLG) equation, which is a nonlinear system of partial differential equations. In the LLG equation, the length of magnetization is conserved and the system energy is dissipative. Implicit and semi-implicit schemes have often been used in micromagnetics simulations due to their unconditional numerical stability. In more details, implicit schemes preserve the properties of the LLG equation, but solve a nonlinear system of equations per time step. In contrast, semi-implicit schemes only solve a linear system of equations, while additional operations are needed to preserve the length of magnetization. It still remains unclear which one shall be used if both implicit and semi-implicit schemes are available. In this work, using the implicit Crank-Nicolson (ICN) scheme as a benchmark, we propose to make this implicit scheme semi-implicit. Stability and convergence analysis, and numerical performance in terms of accuracy and efficiency are systematically studied. Based on these results, we conclude that a semi-implicit scheme is superior to its implicit analog both theoretically and numerically, and we recommend the semi-implicit scheme in micromagnetics simulations if both methods are available. © 2023 American Institute of Mathematical Sciences. All rights reserved.","Crank-Nicolson scheme; Landau-Lifshitz-Gilbert equation; micromagnetics simulations; Semi-implicit scheme","","","","","","Postgraduate Research & Practice Innovation Program of Jiangsu Province, (KYCX22 3179); National Science Foundation, NSF, (DMS-2012269); National Natural Science Foundation of China, NSFC, (11501399, 11971021, 12271360)","Acknowledgments. This work was supported by the Postgraduate Research & Practice Innovation Program of Jiangsu Province KYCX22 3179 (Y. Sun), NSFC grants 11971021 (J. Chen), 12271360 and 11501399 (R. Du), and NSF DMS-2012269 (C. Wang).","(2000); Alouges F., Jaisson P., Convergence of a finite elements discretization for the Landau-Lifshitz equations, Math. Models Methods Appl. Sci, 16, pp. 299-316, (2006); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal, 44, pp. 1405-1419, (2006); Boscarino S., Filbet F., Russo G., High order semi-implicit schemes for time dependent partial differential equations, J. Sci. Comput, 68, pp. 975-1001, (2016); Browder F. E., Nonlinear elliptic boundary value problems. II, Trans. Am. Math. Soc, 117, pp. 530-550, (1965); Chen J., Wang C., Xie C., Convergence analysis of a second-order semi-implicit projection method for Landau-Lifshitz equation, Appl. Numer. Math, 168, pp. 55-74, (2021); Cimrak I., Error estimates for a semi-implicit numerical scheme solving the Landau-Lifshitz equation with an exchange field, IMA J. Numer. Anal, 25, pp. 611-634, (2005); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch . Comput. Methods Eng, 15, pp. 277-309, (2008); d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, J. Comput. Phys, 209, pp. 730-753, (2005); Wang X., Numerical methods for the Landau–Lifshitz equation, SIAM J. Numer. Anal, 38, pp. 1647-1665, (2000); Falgout R. D., Yang U. M., hypre: A library of high performance preconditioners, Computational Science — ICCS 2002, pp. 632-641, (2002); Fuwa A., Ishiwata T., Tsutsumi M., Finite difference scheme for the Landau-Lifshitz equation, Jpn. J. Ind. Appl. Math, 29, pp. 83-110, (2012); Gao H., Optimal error estimates of a linearized backward Euler FEM for the Landau–Lifshitz equation, SIAM J. Numer. Anal, 52, pp. 2574-2593, (2014); Gilbert T. L., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev, 100, (1955); Hertel R., Kronmuller H., Adaptive finite element mesh refinement techniques in three-dimensional micromagnetic modeling, IEEE Trans. Magn, 34, pp. 3922-3930, (1998); Kim E., Lipnikov K., The mimetic finite difference method for the Landau-Lifshitz equation, J. Comput. Phys, 328, pp. 109-130, (2017); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Perspectives in Theoretical Physics, pp. 51-65, (1992); Lewis D., Nigam N., Geometric integration on spheres and some interesting applications, J. Comput. Appl. Math, 151, pp. 141-170, (2003); Li P., Xie C., Du R., Chen J., Wang X., Two improved Gauss-Seidel projection methods for Landau-Lifshitz-Gilbert equation, J. Comput. Phys, 401, (2020); Minty G. J., On a“monotonicity” method for the solution of nonlinear equations in Banach spaces, Proc. Natl. Acad. Sci, 50, pp. 1038-1041, (1963); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the landau-lifshitz-gilbert equation for micromagnetics, Jpn. J. Appl. Phys, 28, pp. 2485-2507, (1989); Praetorius D., Ruggeri M., Stiftner B., Convergence of an implicit-explicit midpoint scheme for computational micromagnetics, Comput. Math. with Appl, 75, pp. 1719-1738, (2018); Schrefl T., Suess D., Scholz W., Forster H., Tsiantos V., Fidler J., Finite element micromagnetics, Computational Electromagnetics, pp. 165-181, (2003); Zutic I., Fabian J., Sarma S. D., Spintronics: Fundamentals and applications, Rev. Mod. Phys, 76, pp. 323-410, (2004); Wang X., Garcia-Cervera C. J., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, pp. 357-372, (2001); Xie C., Garcia-Cervera C. J., Wang C., Zhou Z., Chen J., Second-order semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys, 404, (2020); Yang L., Chen J., Hu G., A framework of the finite element solution of the Landau-Lifshitz-Gilbert equation on tetrahedral meshes, J. Comput. Phys, 431, (2021); Yang L., Hu G., An adaptive finite element solver for demagnetization field calculation, Adv. Appl. Math. Mech, 11, pp. 1048-1063, (2019); Zheng Y., Zhu J., Switching field variation in patterned submicron magnetic film elements, J. Appl. Phys, 81, pp. 5471-5473, (1997)","","","American Institute of Mathematical Sciences","","","","","","15313492","","","","English","Discrete Contin. Dyn. Syst. Ser. B","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85159373039" +"Hu Y.; Xu J.; Wang J.; Xu W.","Hu, Youkang (57486581000); Xu, Jing (58408467700); Wang, Jiyao (57222756020); Xu, Wei (57222754849)","57486581000; 58408467700; 57222756020; 57222754849","Physics-Inspired Multimodal Feature Fusion Cascaded Networks for Data-Driven Magnetic Core Loss Modeling","2024","IEEE Transactions on Power Electronics","39","9","","11356","11367","11","2","10.1109/TPEL.2024.3403708","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85194031131&doi=10.1109%2fTPEL.2024.3403708&partnerID=40&md5=be15b6393e579f30c036e5da7fb51956","Southeast University, School of Electrical Engineering, Nanjing, 210096, China","Hu Y., Southeast University, School of Electrical Engineering, Nanjing, 210096, China; Xu J., Southeast University, School of Electrical Engineering, Nanjing, 210096, China; Wang J., Southeast University, School of Electrical Engineering, Nanjing, 210096, China; Xu W., Southeast University, School of Electrical Engineering, Nanjing, 210096, China","This article proposes a physics-inspired multimodal feature fusion cascaded network (PI-MFF-CN) for data-driven magnetic core loss modeling based on MagNet database. The proposed methodology consists of two cascaded submodels: the physics-inspired network model and the multimodal feature fusion network model. First, a network model inspired by physics and related micromagnetism, is developed based on the Landau-Lifshitz-Gilbert (LLG) equation. It provides new sequence information (HLLG (t)) for the next cascaded core loss prediction model. This addresses the limitation where H(t) waveforms are unable to participate in the actual prediction process. With embedded physical micromagenetic parameters (A, K, Ms) in the gradient learning process of the neural network, the trained physics-inspired network can be regarded as the inverse model (B(t)→HLLG(t)) of LLG Equation having physical interpretability. Then, in order to address a series of challenges in multimodal information learning, a multimodal feature fusion-based network model is proposed. This approach combines the advantages of convolutional neural network (CNN) and fully connected neural network (FCNN) to learn hybrid sequence-scale data. Specifically, it employs parallel CNN branches for sequence feature mappings, followed by concatenating these mappings with other scalar data into an FCNN for global learning. To validate the effectiveness of the proposed method, this article trains and optimizes the proposed models based on MagNet database, and then a series of experiments including extensive material validation (Ferroxcube-3C90, 3C94 & TDK-N27, N30, N49, and N87) were carried out. A series of experimental outcomes demonstrate that the proposed PI-MFF-CN-based method is generalized and robust in accurately predicting magnetic core losses. © 1986-2012 IEEE.","Convolutional neural network (CNN); fully connected neural network (FCNN); Landau-Lifshitz-Gilbert (LLG) equation; magnetic core loss; multimodal feature fusion","Convolution; Forecasting; Inverse problems; Learning systems; Magnetic cores; Magnetic moments; Mapping; Convolutional neural network; Core loss; Fully connected neural network; Landau-Lifshitz-Gilbert equations; Magnetic core loss; Magneto-mechanical effects; Multimodal feature fusions; Neural networks","","","","","","","Roshen W., Ferrite core loss for power magnetic components design, IEEE Trans. Magn, 27, 6, pp. 4407-4415, (1991); Hanson A.J., Belk J.A., Lim S., Sullivan C.R., Perreault D.J., Measurements and performance factor comparisons of magnetic materials at high frequency, IEEE Trans. Power Electron, 31, 11, pp. 7909-7925, (2016); Mu M., Li Q., Gilham D.J., Lee F.C., Ngo K.D.T., New core loss measurement method for high-frequency magnetic materials, IEEE Trans. Power Electron, 29, 8, pp. 4374-4381, (2014); Venkatachalani K., Sullivan C.R., Abdallah T., Tacca H., Accurate prediction of ferrite core loss with non-sinusoidal waveforms using only Steinmetz parameters, Proc. IEEEWorkshop Comput. Power Electron, pp. 36-41, (2002); Rasekh N., Wang J., Yuan X., Artificial neural network aided loss maps for inductors and transformers, IEEE Open J. Power Electron, 3, pp. 886-898, (2022); Matsumori H., Shimizu T., Wang X., Blaabjerg F., A practical core loss model for filter inductors of power electronic converters, IEEE J. Emerg. Sel. Topics Power Electron, 6, 1, pp. 29-39, (2018); Serrano D., Et al., Why MagNet: Quantifying the complexity of modeling power magnetic material characteristics, IEEE Trans. Power Electron, 38, 11, pp. 14292-14316, (2023); Li H., Et al., How MagNet: Machine learning framework for modeling power magnetic material characteristics, IEEE Trans. Power Electron, 38, 12, pp. 15829-15853, (2023); Li H., Serrano D., Wang S., Chen M., MagNet-AI: Neural network as datasheet for magnetics modeling and material recommendation, IEEE Trans. Power Electron, 38, 12, pp. 15854-15869, (2023); Steinmetz C.P., On the law of hysteresis, Trans. Amer. Inst. Elect. Engineers, 9, 1, pp. 1-64, (1892); Reinert J., Brockmeyer A., De Doncker R.W.A.A., Calculation of losses in ferro-and ferrimagnetic materials based on the modified Steinmetz equation, IEEE Trans. Ind. Appl, 37, 4, pp. 1055-1061, (2001); Muhlethaler J., Biela J., Kolar J.W., Ecklebe A., Improved core loss calculation for magnetic components employed in power electronic Systems, IEEE Trans. Power Electron, 27, 2, pp. 964-973, (2012); Han Y., Cheung G., Li A., Sullivan C.R., Perreault D.J., Evaluation of magnetic materials for very high frequency power applications, IEEE Trans. Power Electron, 27, 1, pp. 425-435, (2012); LeCun Y., Bengio Y., Hinton G., Deep learning, Nature, 521, pp. 436-444, (2015); Ren L., Dong J., Wang X., Meng Z., Zhao L., Deen M.J., A datadriven auto-CNN-LSTM prediction model for lithium-ion battery remaining useful life, IEEE Trans. Ind. Inform, 17, 5, pp. 3478-3487, (2021); Kucuk I., Prediction of hysteresis loop in magnetic cores using neural network and genetic algorithm, J. Magnetism Magn. Mater, 305, 2, pp. 423-427, (2006); Zhao S., Blaabjerg F., Wang H., An overview of artificial intelligence applications for power electronics, IEEE Trans. Power Electron, 36, 4, pp. 4633-4658, (2021); Amoiralis E.I., Georgilakis P.S., Kefalas T.D., Tsili M.A., Kladas A.G., Artificial intelligence combined with hybrid FEM-BE techniques for global transformer optimization, IEEE Trans. Magn, 43, 4, pp. 1633-1636, (2007); Dogariu E., Li H., Serrano Lopez D., Wang S., Luo M., Chen M., Transfer learning methods for magnetic core loss modeling, Proc. IEEE Workshop Control Model. Power Electron, pp. 1-6, (2021); Santamargarita D., Molinero D., Bueno E., Marron M., Vasic M., On-line monitoring of maximum temperature and loss distribution of a medium frequency transformer using artificial neural networks, IEEE Trans. Power Electron, 38, 12, pp. 15818-15828, (2023); Ando S., Suka Y., Classification of temporal and sequential data using bag-of-subsequences features, Proc. IEEE Int. Conf.DataMining Workshop, pp. 1417-1424, (2015); Yang L., Wu Z., Hong J., Long J., MCL: A contrastive learning method for multimodal data fusion in violence detection, IEEE Signal Process. Lett, 30, pp. 408-412, (2023); Wang D., Li Y., Jia L., Song Y., Liu Y., Novel three-stage feature fusion method of multimodal data for bearing fault diagnosis, IEEE Trans. Instrum. Meas, 70, (2021); Serrano D., Et al., Neural network as datasheet: Modeling B-H loops of power magnetics with sequence-to-sequence LSTM encoder-decoder architecture, Proc. IEEE Workshop Comput. Power Electron, pp. 1-8, (2022); Deng J., Wang W., Ning Z., Venugopal P., Popovic J., Rietveld G., High-frequency core loss modeling based on knowledge-aware artificial neural network, IEEE Trans. Power Electron, 39, 2, pp. 1968-1973, (2024); Bar'yakhtar V.G., Ivanov B.A., The Landau-Lifshitz equation: 80 years of history, advances, and prospects, Low Temp. 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Signal Process, 100, pp. 439-453, (2018); Wang F., Liu R., Hu Q., Chen X., Cascade convolutional neural network with progressive optimization for motor fault diagnosis under nonstationary conditions, IEEE Trans. Ind. Inform, 17, 4, pp. 2511-2522, (2021); Bjork R., Poulsen E.B., Nielsen K.K., Insinga A.R., MagTense: A micromagnetic framework using the analytical demagnetization tensor, J. Magnetism Magn. Mater, 535, (2021); Peker E., Wiesel A., Fitting generalized multivariate huber loss functions, IEEE Signal Process. Lett, 23, 11, pp. 1647-1651, (2016); Zheng Z., Zhao J., Wang L., Dong F., Yang X., Efficient optimization design method of PMSLM based on deep adaptive ridge regression with embedded analytical mapping function, IEEE Trans. Ind. Electron, 69, 8, pp. 8243-8254, (2022); Yating G., Wu W., Qiongbin L., Fenghuang C., Qinqin C., Fault diagnosis for power converters based on optimized temporal convolutional network, IEEE Trans. Instrum. Meas, 70, (2021); Buslim N., Rahmatullah I.L., Setyawan B.A., Alamsyah A., Comparing bitcoin's prediction model using GRU, RNN, and LSTM by hyperparameter optimization grid search and random search, Proc. 9th Int. Conf. Cyber IT Serv. Manage, pp. 1-6, (2021); Arruti A., Anzola J., Perez-Cebolla F.J., Aizpuru I., Mazuela M., The composite improved generalized steinmetz equation (ciGSE): An accurate model combining the composite waveform hypothesis with classical approaches, IEEE Trans. Power Electron, 39, 1, pp. 1162-1173, (2024)","W. Xu; Southeast University, School of Electrical Engineering, Nanjing, 210096, China; email: weixu@seu.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","08858993","","ITPEE","","English","IEEE Trans Power Electron","Article","Final","","Scopus","2-s2.0-85194031131" +"Alekhin A.; Lomonosov A.M.; Leo N.; Ludwig M.; Vlasov V.S.; Kotov L.; Leitenstorfer A.; Gaal P.; Vavassori P.; Temnov V.","Alekhin, Alexandr (56417520000); Lomonosov, Alexey M. (7003432320); Leo, Naëmi (36175762300); Ludwig, Markus (56367272200); Vlasov, Vladimir S. (12762549500); Kotov, Leonid (6701471708); Leitenstorfer, Alfred (7004765390); Gaal, Peter (9239633800); Vavassori, Paolo (7004306454); Temnov, Vasily (7004062544)","56417520000; 7003432320; 36175762300; 56367272200; 12762549500; 6701471708; 7004765390; 9239633800; 7004306454; 7004062544","Quantitative Ultrafast Magnetoacoustics at Magnetic Metasurfaces","2023","Nano Letters","23","20","","9295","9302","7","8","10.1021/acs.nanolett.3c02336","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85175270990&doi=10.1021%2facs.nanolett.3c02336&partnerID=40&md5=8173ebb98b5c1b7413a9686f9734c5ff","Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, Paris, 75013, France; CIC nanoGUNE BRTA, Donostia-San Sebastian, E-20018, Spain; B+W Department, Offenburg University of Applied Sciences, Offenburg, 77652, Germany; Deutsches Elektronen-Synchrotron DESY, Hamburg, 22607, Germany; LSI, Ecole Polytechnique, CEA/DRF/IRAMIS, CNRS, Institut Polytechnique de Paris, Palaiseau, F-91128, France; Department of Physics and Center for Applied Photonics, University of Konstanz, Konstanz, D-78457, Germany; Leibniz Institut für Kristallzüchtung, Max-Born-Strasse 2, Berlin, 12489, Germany; IKERBASQUE, Basque Foundation for Science, Bilbao, E-48013, Spain","Alekhin A., Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, Paris, 75013, France, CIC nanoGUNE BRTA, Donostia-San Sebastian, E-20018, Spain; Lomonosov A.M., B+W Department, Offenburg University of Applied Sciences, Offenburg, 77652, Germany; Leo N., CIC nanoGUNE BRTA, Donostia-San Sebastian, E-20018, Spain; Ludwig M., Deutsches Elektronen-Synchrotron DESY, Hamburg, 22607, Germany; Vlasov V.S., LSI, Ecole Polytechnique, CEA/DRF/IRAMIS, CNRS, Institut Polytechnique de Paris, Palaiseau, F-91128, France; Kotov L., LSI, Ecole Polytechnique, CEA/DRF/IRAMIS, CNRS, Institut Polytechnique de Paris, Palaiseau, F-91128, France; Leitenstorfer A., Department of Physics and Center for Applied Photonics, University of Konstanz, Konstanz, D-78457, Germany; Gaal P., Leibniz Institut für Kristallzüchtung, Max-Born-Strasse 2, Berlin, 12489, Germany; Vavassori P., CIC nanoGUNE BRTA, Donostia-San Sebastian, E-20018, Spain, IKERBASQUE, Basque Foundation for Science, Bilbao, E-48013, Spain; Temnov V., LSI, Ecole Polytechnique, CEA/DRF/IRAMIS, CNRS, Institut Polytechnique de Paris, Palaiseau, F-91128, France","Femtosecond (fs) time-resolved magneto-optics is applied to investigate laser-excited ultrafast dynamics of one-dimensional nickel gratings on fused silica and silicon substrates for a wide range of periodicities Λ = 400-1500 nm. Multiple surface acoustic modes with frequencies up to a few tens of GHz are generated. Nanoscale acoustic wavelengths Λ/n have been identified as nth-spatial harmonics of Rayleigh surface acoustic wave (SAW) and surface skimming longitudinal wave (SSLW), with acoustic frequencies and lifetimes being in agreement with theoretical calculations. Resonant magnetoelastic excitation of the ferromagnetic resonance (FMR) by SAW’s third spatial harmonic, and, most interestingly fingerprints of the parametric resonance at 1/2 SAW frequency have been observed. Numerical solutions of Landau-Lifshitz-Gilbert (LLG) equation magnetoelastically driven by complex polychromatic acoustic fields quantitatively reproduce all resonances at once. Thus, our results provide a solid experimental and theoretical base for a quantitative understanding of ultrafast fs-laser-driven magnetoacoustics and tailoring the magnetic-grating-based metasurfaces at the nanoscale. © 2023 American Chemical Society.","Landau−Lifshitz−Gilbert equation; magnetic metasurfaces; magnetic nanostructures; magnetization dynamics; picosecond ultrasonics; ultrafast magnetoacoustics","Acoustic surface wave devices; Acoustic waves; Fused silica; Nanomagnetics; Ultrasonics; Landau-Lifshitz-Gilbert equations; Magnetic metasurface; Magnetic nanostructures; Magnetization dynamics; Magnetoacoustics; Metasurface; Nano scale; Picosecond ultrasonics; Ultra-fast; Ultrafast magnetoacoustic; Acoustic fields","","","","","Universität Hamburg, UH; Conseil Régional des Pays de la Loire; ANR-DFG; European Regional Development Fund, ERDF; Fondation de l'École Polytechnique, FX; Agence Nationale de la Recherche, ANR, (ANR-15-CE24-0032); Ministerio de Ciencia, Innovación y Universidades, MCIU, (CEX2020-001038-M); Ministerio de Ciencia e Innovación, MICINN, (PID2021-123943NB-I00); Deutsche Forschungsgemeinschaft, DFG, (AL2143/3-1)","The authors acknowledge Gwenae\u0308lle Vaudel, the research engineer on the femtosecond laser platform at the IMMM CNRS 6283, Le Mans University, for technical and administrative assistance, Roman Bauer from the University of Hamburg and Antonia Ghita and Tudor-Gabriel Mocioi from Ecole Polytechnique for fruitful discussions. The financial support though the Deutsche Forschungsgemeinschaft (AL2143/3-1), the ANR-DFG \u201CPPMI-NANO\u201D (Grant No. ANR-15-CE24-0032), and Strategie internationale \u201CNNN-Telecom\u201D de la Region Pays de La Loire is gratefully acknowledged. P.V. and N.L. acknowledge support from the Spanish Ministry of Science, Innovation and Universities under the Maria de Maeztu Units of Excellence Programme (Grant No. CEX2020-001038-M) and the Spanish Ministry of Science and Innovation via Project No. PID2021-123943NB-I00 (MCIN/FEDER).","Sander D., The 2017 Magnetism Roadmap, J. Phys. D: Appl. Phys., 50, (2017); Stockman M.I., Roadmap on plasmonics, Journal of Optics, 20, (2018); Temnov V.V., Razdolski I., Pezeril T., Makarov D., Seletskiy D., Melnikov A., Nelson K.A., Towards the nonlinear acousto-magneto-plasmonics, Journal of Optics, 18, (2016); Yang W.-G., Schmidt H., Acoustic control of magnetism toward energy-efficient applications, Applied Physics Reviews, 8, (2021); Vlasov V., Golov A., Kotov L., Shcheglov V., Lomonosov A., Temnov V., The modern problems of ultrafast magnetoacoustics, Acoustical Physics, 68, pp. 18-47, (2022); Kimel A., Zvezdin A., Sharma S., Shallcross S., De Sousa N., Garcia-Martin A., Salvan G., Hamrle J., Stejskal O., McCord J., The 2022 magneto-optics roadmap, J. Phys. D: Appl. Phys., 55, (2022); Antonelli G.A., Maris H.J., Malhotra S.G., Harper J.M.E., Picosecond ultrasonics study of the vibrational modes of a nanostructure, J. Appl. Phys., 91, pp. 3261-3267, (2002); Antonelli G.A., Perrin B., Daly B.C., Cahill D.G., Characterization of Mechanical and Thermal Properties Using Ultrafast Optical Metrology, MRS Bull., 31, pp. 607-613, (2006); Comin A., Giannetti C., Samoggia G., Vavassori P., Grando D., Colombi P., Bontempi E., Depero L.E., Metlushko V., Ilic B., Parmigiani F., Elastic and Magnetic Dynamics of Nanomagnet-Ordered Arrays Impulsively Excited by Subpicosecond Laser Pulses, Phys. Rev. Lett., 97, (2006); Giannetti C., Revaz B., Banfi F., Montagnese M., Ferrini G., Cilento F., Maccalli S., Vavassori P., Oliviero G., Bontempi E., Depero L.E., Metlushko V., Parmigiani F., Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction experiments, Phys. Rev. B, 76, (2007); Janusonis J., Chang C.L., Jansma T., Gatilova A., Vlasov V.S., Lomonosov A.M., Temnov V.V., Tobey R.I., Ultrafast magnetoelastic probing of surface acoustic transients, Phys. Rev. B, 94, (2016); Chang C.L., Lomonosov A.M., Janusonis J., Vlasov V.S., Temnov V.V., Tobey R.I., Parametric frequency mixing in a magnetoelastically driven linear ferromagnetic-resonance oscillator, Phys. Rev. B, 95, (2017); Chang C.L., Tamming R.R., Broomhall T.J., Janusonis J., Fry P.W., Tobey R.I., Hayward T.J., Selective Excitation of Localized Spin-Wave Modes by Optically Pumped Surface Acoustic Waves, Physical Review Applied, 10, (2018); Chernov A.I., Kozhaev M.A., Ignatyeva D.O., Beginin E.N., Sadovnikov A.V., Voronov A.A., Karki D., Levy M., Belotelov V.I., All-dielectric nanophotonics enables tunable excitation of the exchange spin waves, Nano Lett., 20, pp. 5259-5266, (2020); Tran N.-M., Chioar I.-A., Stein A., Alekhin A., Juve V., Vaudel G., Razdolski I., Kapaklis V., Temnov V., Observation of the nonlinear Wood’s anomaly on periodic arrays of nickel nanodimers, Phys. Rev. B, 98, (2018); Colletta M., Gachuhi W., Gartenstein S.A., James M.M., Szwed E.A., Daly B.C., Cui W., Antonelli G.A., Picosecond ultrasonic study of surface acoustic waves on periodically patterned layered nanostructures, Ultrasonics, 87, pp. 126-132, (2018); Mathieu E., Mémoire sur le mouvement vibratoire d’une membrane de forme elliptique, Journal de mathématiques pures et appliquées, 13, pp. 137-203, (1868); Vlasov V.S., Lomonosov A.M., Golov A.V., Kotov L.N., Besse V., Alekhin A., Kuzmin D.A., Bychkov I.V., Temnov V.V., Magnetization switching in bistable nanomagnets by picosecond pulses of surface acoustic waves, Phys. Rev. B, 101, (2020); Maccaferri N., Gabbani A., Pineider F., Kaihara T., Tapani T., Vavassori P., Magnetoplasmonics in confined geometries: Current challenges and future opportunities, Appl. Phys. Lett., 122, (2023); Koya A.N., Romanelli M., Kuttruff J., Henriksson N., Stefancu A., Grinblat G., De Andres A., Schnur F., Vanzan M., Marsili M., Advances in ultrafast plasmonics, Applied Physics Reviews, 10, (2023); Zhu T., Maris H.J., Tauc J., Attenuation of longitudinal-acoustic phonons in amorphous SiO 2 at frequencies up to 440 GHz, Phys. Rev. B, 44, (1991); Cuffe J., Ristow O., Chavez E., Shchepetov A., Chapuis P.-O., Alzina F., Hettich M., Prunnila M., Ahopelto J., Dekorsy T., Lifetimes of confined acoustic phonons in ultrathin silicon membranes, Physical review letters, 110, (2013); Lin H., Maris H.J., Freund L.B., Lee K.Y., Luhn H., Kern D.P., Study of vibrational modes of gold nanostructures by picosecond ultrasonics, J. Appl. Phys., 73, pp. 37-45, (1993); Wortman J.J., Evans R.A., Young’s Modulus, Shear Modulus, and Poisson’s Ratio in Silicon and Germanium, J. Appl. Phys., 36, pp. 153-156, (1965); Pratt R.G., Lim T.C., ACOUSTIC SURFACE WAVES ON SILICON, Appl. Phys. Lett., 15, pp. 403-405, (1969); Auld B., Acoustic Fields and Waves in Solids, 2, (1990); Heinrich B., Spin Relaxation in Magnetic Metallic Layers and Multilayers BT - Ultrathin Magnetic Structures III: Fundamentals of Nanomagnetism, pp. 143-210, (2005); Birss R., Lee E., The saturation magnetostriction constants of nickel within the temperature range-196 to 365 C, Proceedings of the Physical Society, 76, (1960); Bigot J.-Y., Vomir M., Andrade L.H.F., Beaurepaire E., Ultrafast magnetization dynamics in ferromagnetic cobalt: The role of the anisotropy, Chem. Phys., 318, pp. 137-146, (2005); Ghita A., Mocioi T.-G., Lomonosov A.M., Kim J., Kovalenko O., Vavassori P., Temnov V.V., Anatomy of ultrafast quantitative magnetoacoustics in freestanding nickel thin films, Phys. Rev. B, 107, (2023); Bombeck M., Salasyuk A.S., Glavin B.A., Scherbakov A.V., Bruggemann C., Yakovlev D.R., Sapega V.F., Liu X., Furdyna J.K., Akimov A.V., Bayer M., Excitation of spin waves in ferromagnetic (Ga,Mn)As layers by picosecond strain pulses, Phys. Rev. B, 85, (2012); Besse V., Golov A.V., Vlasov V.S., Alekhin A., Kuzmin D., Bychkov I.V., Kotov L.N., Temnov V.V., Generation of exchange magnons in thin ferromagnetic films by ultrashort acoustic pulses, J. Magn. Magn. Mater., 502, (2020); Vernik U., Lomonosov A.M., Vlasov V.S., Kotov L.N., Kuzmin D.A., Bychkov I.V., Vavassori P., Temnov V.V., Resonant phonon-magnon interactions in free-standing metal-ferromagnet multilayer structures, Phys. Rev. B, 106, (2022); An K., Litvinenko A.N., Kohno R., Fuad A.A., Naletov V.V., Vila L., Ebels U., de Loubens G., Hurdequint H., Beaulieu N., Coherent long-range transfer of angular momentum between magnon Kittel modes by phonons, Phys. Rev. B, 101, (2020); Mocioi T.-G., Ghita A., Temnov V.V., Towards Resonantly Enhanced Acoustic Phonon-Exchange Magnon Interactions at THz Frequencies, Magnetochemistry, 9, (2023); Royer D., Dieulesaint E., Elastic waves in solids I: Free and guided propagation, (1999)","A. Alekhin; Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, Paris, 75013, France; email: alexandr.alekhin@u-paris.fr; V. Temnov; LSI, Ecole Polytechnique, CEA/DRF/IRAMIS, CNRS, Institut Polytechnique de Paris, Palaiseau, F-91128, France; email: vasily.temnov@cnrs.fr","","American Chemical Society","","","","","","15306984","","NALEF","37820262","English","Nano Lett.","Article","Final","","Scopus","2-s2.0-85175270990" +"Ogrin F.Y.","Ogrin, Feodor Y. (57193655015)","57193655015","Non-linear ferrite dynamics for microwave thin film technologies","2023","International Conference on Metamaterials, Photonic Crystals and Plasmonics","","","","442","","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85174622328&partnerID=40&md5=8cf4902fa8897f991ce8d63866db13eb","School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom","Ogrin F.Y., School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom","Electromagnetic (EM) shock waves are normally associated with nuclear explosions, and as such a rare phenomenon. Analogous to a sonic boom, it is an interference effect, resulting in a surge of EM power, propagating with a speed of light. Since early 60s there was an interest to harness the effect to make it more technologically practical. One possible way to do that is within the configuration of a magnetically loaded transmission line (e.g. coaxial line). While the coaxial design has been proven to be viable for generating high power microwaves [1], its practicality in consumer technology is less so obvious due to high voltages (typically 10-100th kV) needed in order to obtain the effect. Theoretically, this problem can be resolved by scaling down the dimensions of the transmission line. Reducing down to microscopic dimensions, it is possible to obtain the effect at voltages as low as 1-10 Volts. At this level the effect can be usefully utilised in a range of electronic devices, and particularly the high frequency communications, which are of great demand in the development of modern IC technologies. Modelling extremely non-linear EM dynamics is however a challenging problem, that can not be done by the available conventional solvers. Here we approach the problem by using a unique modelling technique allowing to solve Maxwell equations in parallel to Landau-Lifshits-Gilbert’s (LLG) [2]. The unique nature of our 3D FDTD-LLG code, is in the fact that LLG equation is solved exactly, accounting for the given geometry with the presence of any type of conducting or non-conducting materials [3]. This means that all non-linear effects can be calculated precisely without any linearization or imposed constraints. © 2023, META Conference. All rights reserved.","","","","","","","","","Ulmasculov, Et al., J. Phys.: Conf. Ser, 830, (2017); Aziz M. M., Progress In Electromagnetics Research B, 15, (2009)","","Lalanne P.; Zouhdi S.","META Conference","","13th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2023","18 July 2023 through 21 July 2023","Paris","300609","24291390","","","","English","Int. Conf. Mater. Photon. Cryst. Plasmon.","Conference paper","Final","","Scopus","2-s2.0-85174622328" +"Çam N.","Çam, Necda (58763523700)","58763523700","A micromagnetic research on nonequilibrium phase transitions of cobalt nanorings with varying ring widths","2024","European Physical Journal B","97","12","188","","","","0","10.1140/epjb/s10051-024-00831-z","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85211094178&doi=10.1140%2fepjb%2fs10051-024-00831-z&partnerID=40&md5=1adf92d35e263f72dcd530452d0eedb9","Department of Physics, Dokuz Eylül University, Izmir, 35160, Turkey","Çam N., Department of Physics, Dokuz Eylül University, Izmir, 35160, Turkey","Abstract: In this study, the effects of the arm width of the Co 2D-nanoring structure, along with the amplitude and frequency of the external dynamic sinusoidal magnetic field on nonequilibrium phase transitions have been comprehensively investigated. Dynamic magnetic hysteresis curves have been obtained through the numerical solution of the nonlinear Landau–Lifshitz–Gilbert (LLG) equation using OOMMF software. Dynamic hysteresis characteristics, including hysteresis loop area, remanent magnetization, and coercive field have been calculated as functions of frequency. It has been found that nonequilibrium phase transitions are significantly influenced by the arm width, in addition to the frequency and amplitude of the applied external dynamic field. Numerical results highlight that increasing the arm width of the nanoring system causes the transition frequency of the dynamically ordered phase to shift to lower values. © The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2024.","","Coercive force; Dynamics; Hysteresis loops; Magnetic field effects; Magnetic hysteresis; Cobalt nanorings; External dynamics; Landau-Lifshitz-Gilbert equations; Magnetic hysteresis curves; Micromagnetics; Nano-ring structures; Nonequilibrium phase transitions; Numerical solution; Ring width; Sinusoidal magnetic fields; Nanorings","","","","","","","Li K., Xu J., Li P., Fan Y., Composites B Eng, 228, (2022); Das R., Witanachchi C., Nemati Z., Kalappattil V., Rodrigo I., Garci J.A., Garaio E., Alonso J., Lam V.D., Le A.-T., Phan M.-H., Srikanth H., Appl. Sci, 10, (2020); Miller M.M., Prinz G.A., Cheng S.F., Bounnak S., Appl. Phys. Lett, 81, 12, (2002); Zhu J.-G., Zheng Y., Prinz G.A., J. Appl. Phys, 87, 9, (2000); Lu Y., Shi C., Hu M.-J., Xu Y.-J., Yu L., Wen L.-P., Zhao Y., Xu W.-P., Yu S.-H., Adv. Funct. Mater, 20-21, (2010); Vaz C.A.F., Hayward T.J., Llandro J., Schackert F., Morecroft D., Bland J.A.C., Klaui M., Laufenberg M., Backes D., Rudiger U., Castano F.J., Ross C.A., Heyderman L.J., Nolting F., Locatelli A., Faini G., Cherifi S., Wernsdorfer W., Condens J., Matter Phys, 19, (2007); Rolff H., Pfutzner W., Heyn C., Grundler D., J. Magn. Magn. Mater, 272, pp. 1623-1624, (2004); Jain S., Wang C.C., Adeyeye A.O., Nanotechnology, 19, 8, (2008); Landeros P., Escrig J., Altbir D., Bahiana M., Castro J., J. Appl. Phys, 100, (2006); Tian C., Chaudhuri U., Singh N., Adeyeye A.O., Nanotechnology, 31, 14, (2020); Dias C.S.B., Hanchuk T.D.M., Wender H., Shigeyosi W.T., Kobarg J., Rossi A.L., Tanaka M.N., Cardoso M.B., Garcia F., Sci. Rep, 7, 1, (2017); Bai X., Peng R., Xing H., Xie S., Zhang J., Zhang S., Deng X., Li X., Peng Y., Zheng X., Results Phys, 58, (2024); He K., Smith D.J., McCartney M.R., J. Appl. Phys, 107, 9, (2010); Torres-Heredia J.J., Lopez-Urias F., Munoz-Sandoval E., J. Magn. Magn. Mater, 294, pp. e1-e5, (2005); Lopez-Urias F., Torres-Heredia J.J., Munoz-Sandoval E., Phys. Rev. B Condens. Matter, 483, pp. 62-68, (2016); Torres-Heredia J.J., Lopez-Urias F., Munoz-Sandoval E., J. Magn. Magn. Mater, 305, (2006); Steinmetz P., Ehrmann A., Condens. Matter, 6, 2, (2021); Lal M., Sakshath S., Parakkat V.M., Anil Kumar P.S., AIP Adv, 8, 5, (2018); Bachar F.-Z., Schroder C., Ehrmann A., J. Magn. Magn. Mater, 537, (2021); Wang X.H., Purnama I., Goolaup S., Lew W.S., J. Phys Conf. Ser, 266, (2011); Escrig J., Landeros P., Altbir D., Bahiana M., Castro J., Appl. Phys. Lett., 89, 13, (2006); Lal M., Sakshath S., Venkateswarlu D., Anil Kumar P.S., J. Magn. Magn. Mater, 448, pp. 153-158, (2018); Palma J.L., Morales-Concha C., Leighton B., Altbir D., Escrig J., J. Magn. Magn. Mater, 324, 4, pp. 637-641, (2012); Chai G., Wang X., Si M.S., Xue D., Phys. Lett. A, 377, pp. 1491-1494, (2013); Mu C., Jing J., Dong J., Wang W., Xu J., Nie A., Xiang J., Wen F., Liu Z., J. Magn. Magn. Mater, 474, pp. 301-304, (2019); Saavedra E., Riveros A., Palma J.L., Sci. Rep, 11, 1, (2021); Mu C., Song J., Xu J., Wen F., AIP Adv, 6, 6, (2016); Djuhana D., Kadir J.A., Widodo A.T., Kim D.-H., Adv. Mater. Res, 896, pp. 410-413, (2014); Djuhana D., Kurniawan C., Widodo A.T., IOP Conf. Ser. Mater. Sci. Eng, 496, (2019); Djuhana I.D., Kim D.-H., AIP Proc. Conf., 200, (2014); Dantas C.C., de Andrade L.A., Phys. Rev. B, 78, 2, (2008); Das R., Masa J.A., Kalappattil V., Nemati Z., Rodrigo I., Garaio E., Garci J.A., Phan M.-H., Srikanth H., Nanomaterials, 11, 6, (2021); Donahue M.J., Porter D.G., NISTIR No. 6376, (1999); Trudel S., Gaier O., Hamrle J., Hillebrands B., J. Phys. D Appl. Phys, 43, 19, (2010); Kronmuller H., Micromagnetism and the Microstructure of Ferromagnetic Solids, (2003); Dang Xuan N., Dopke C., Blachowicz T., Ehrmann A., Acta Phys. Pol. A, 137, 3, (2020); Cam N., Akinci U., Phys. Lett. A, 500, (2024)","N. Çam; Department of Physics, Dokuz Eylül University, Izmir, 35160, Turkey; email: necda.cam@ogr.deu.edu.tr","","Springer Science and Business Media Deutschland GmbH","","","","","","14346028","","","","English","Eur. Phys. J. B","Article","Final","","Scopus","2-s2.0-85211094178" +"Çam N.","Çam, Necda (58763523700)","58763523700","A micromagnetic study of sample size effects on dynamic hysteresis properties and dynamic phase transitions of Fe and Fe3O4 nanodisks","2024","Journal of Nanoparticle Research","26","9","218","","","","0","10.1007/s11051-024-06131-y","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85203860213&doi=10.1007%2fs11051-024-06131-y&partnerID=40&md5=c99c7971a603b7b876f70d481812b1fb","Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey","Çam N., Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey","The influence of size on the dynamic magnetic hysteresis properties and dynamic phase transitions of Fe and Fe3O4 2D-circular nanodisks with varying diameters has been explored in the micromagnetic framework. This investigation is conducted under a sinusoidal dynamic magnetic field along the x-direction by solving the Landau-Lifshitz-Gilbert (LLG) equation with the OOMMF software at zero temperature. The dynamic hysteresis of nanodisks is profoundly impacted by both the frequency and amplitude of the applied external field, along with the particle size. As particle size decreases, there is an observed increase in the frequency values at which the transition to dynamic ordered frequency occurs in Fe nanodisks, whereas a decrease is noted in the transition frequency values of Fe3O4 nanodisks. © The Author(s), under exclusive licence to Springer Nature B.V. 2024.","coercive field; Dynamic hysteresis; Fe nanodisks; Fe3O4 nanodisks; Hysteresis loop area; LLG equation; Micromagnetism; Model and simulation; Remanent magnetization","Coercive force; Magnetic hysteresis; iron nanoparticle; iron oxide nanoparticle; Coercive field; Dynamic hysteresis; Fe nanodisk; Fe3O4 nanodisk; Hysteresis loop area; Landau-Lifshitz-Gilbert equations; Micromagnetisms; Model and simulation; Nanodisks; Remanent magnetization; Article; frequency analysis; hysteresis; magnetic field; magnetism; mathematical computing; nanoanalysis; particle size; phase transition; sample size; temperature; Hysteresis loops","","","","","","","De D., Goswami S., Chakraborty M., Magnetic memory effect: unfolding magnetic metastabilities, J Magn Magn Mater, 565, (2023); Rocha-Santos T.A., Sensors and biosensors based on magnetic nanoparticles, TrAC, Trends Anal Chem, 62, pp. 28-36, (2014); Banobre-Lopez M., Teijeiro A., Rivas J., Magnetic nanoparticle-based hyperthermia for cancer treatment, Reports of Practical Oncology & Radiotherapy, 18, 6, pp. 397-400, (2013); Khan A.U., Chen L., Ge G., Recent development for biomedical applications of magnetic nanoparticles, Inorg Chem Commun, 134, (2021); Tang S.C., Lo I.M., Magnetic nanoparticles: essential factors for sustainable environmental applications, Water Res, 47, 8, pp. 2613-2632, (2013); Zhou K., Zhou X., Liu J., Huang Z., Application of magnetic nanoparticles in petroleum industry: a review, J Petrol Sci Eng, 188, (2020); Lamouri R., Mounkachi O., Salmani E., Hamedoun M., Benyoussef A., Ez-Zahraouy H., Size effect on the magnetic properties of CoFe2O4 nanoparticles: a Monte Carlo study, Ceram Int, 46, 6, pp. 8092-8096, (2020); Kachkachi H., Nogues M., Tronc E., Garanin D.A., Finite-size versus surface effects in nanoparticles, Journal of Magnetism and Magnetic Materials, 221, 1-2, (2020); Iglesias &#X.002;., Labarta A., Influence of surface anisotropy on the magnetization reversal of nanoparticles, physica status solidi (c), 1, 12, pp. 3481-3484, (2004); Ma Z., Mohapatra J., Wei K., Liu J.P., Sun S., Magnetic nanoparticles: synthesis, anisotropy, and applications, Chem Rev, 123, 7, pp. 3904-3943, (2021); Mohapatra J., Joshi P., Liu J.P., Low-dimensional hard magnetic materials, Prog Mater Sci, 138, (2023); Shava B., Ayodeji F.D., Rahdar A., Iqbal H.M., Bilal M., Magnetic nanoparticles-based systems for multifaceted biomedical applications, Journal of Drug Delivery Science and Technology, 74, (2022); Farzanegan Z., Tahmasbi M., Evaluating the applications and effectiveness of magnetic nanoparticle-based hyperthermia for cancer treatment: a systematic review, Applied Radiation and Isotopes, 198, (2023); Dantas C.C., Gama A.M., Micromagnetic simulations of spinel ferrite particles, Journal of magnetism and magnetic materials, 322, 19, pp. 2824-2833, (2010); Maniotis N., Studying the rate-dependent specific absorption rate in magnetic hyperthermia through multiscale simulations, AIP Advances, 13, 6, (2023); Anand M., Dipolar interaction and sample shape effects on the hysteresis properties of 2d array of magnetic nanoparticles, Pramana, 95, pp. 1-9, (2021); Nomura E., Chiba M., Matsuo S., Noda C., Kobayashi S., Manjanna J., Kawamura Y., Ohishi K., Hiroi K., Suzuki J.I., Magnetization process of cubic Fe3O4 submicron particles studied by polarized small-angle neutron scattering, AIP Advances, 12, 3, (2022); Haseeb M., Li Y.Q., Zhang H.G., Liu W.Q., Zhang P.J., Yue M., Influence and mechanism of surface defects on coercivity of M-type ferrite particles, Surfaces and Interfaces, 46, (2024); Jalali M.H., Shams M.H., Gholizadeh H., Micromagnetic simulation of the shape effect on the permeability and loss tangent of Fe3O4 nanoparticles in the microwave range, J Supercond Novel Magn, 36, 2, pp. 601-609, (2023); Tsuji T., Kobayash S., Enhanced heating efficiency for hollow Fe3O4 spherical submicron particles, AIP Advances, 14, 1, (2024); Anand M., Carrey J., Banerjee V., Role of dipolar interactions on morphologies and tunnel magnetoresistance in assemblies of magnetic nanoparticles, J Magn Magn Mater, 454, pp. 23-31, (2018); Dantas C.C., Analysis of the collective behavior of a 10 by 10 array of Fe3O4 dots in a large micromagnetic simulation, Physica E, 44, 3, pp. 675-679, (2021); Roa N., Restrepo J., Micromagnetic approach to the metastability of a magnetite nanoparticle and specific loss power as function of the easy-axis orientation, Physchem, 3, 3, pp. 290-303, (2023); Ehrmann A., Blachowicz T., Influence of shape and dimension on magnetic anisotropies and magnetization reversal of Py, Fe, and Co nano-objects with four-fold symmetry, AIP Advances, 5, 9, (2015); Bachar F.-Z., Schrorder C., Ehrmann A., Magnetization reversal in Pac-Man shaped Fe nanostructures with varying aperture, J Magn Magn Mater, 537, (2021); Leighton B., Vargas N.M., Altbir D., Escrig J., Tailoring the magnetic properties of Fe asymmetric nanodots, J Magn Magn Mater, 323, 11, pp. 1563-1567, (2011); Djuhana D., Kadir J.A., Widodo A.T., Kim D.H., Micromagnetic study on the dynamic susceptibility spectra of square-patterned ferromagnets, Advanced Materials Research, 896, pp. 410-413, (2014); Djuhana D., Kurniawan C., Widodo A.T., Dynamic susceptibility spectra analysis of ferromagnetic spheres via micromagnetic simulations, InIOP Conference Series: Materials Science and Engineering, 496, (2019); Palma J.L., Morales-Concha C., Leighton B., Altbir D., Escrig J., Micromagnetic simulation of Fe asymmetric nanorings, J Magn Magn Mater, 324, 4, pp. 637-641, (2012); Oncu E., Ehrmann A., Magnetization reversal in concave iron nano-superellipses, Condensed Matter, 6, 2, (2021); Dang Xuan N., Dopke C., Blachowicz T., Ehrmann A., Magnetization reversal in hexagonal nanomagnets, Acta Physica Polonica: A, 137, 3, (2020); Lopez-Urias F., Magnetization patterns simulations of Fe, Ni Co, and permalloy individual nanomagnets, . J Magn Magn Mater, 294, 2, pp. e7-12, (2005); Donahue M.J., Porter D.G., NISTIR No, (1999); Trudel S., Gaier O., Hamrle J., Hillebrands B., Magnetic anisotropy, exchange and damping in cobalt-based full-Heusler compounds: an experimental review, J Phys D Appl Phys, 43, 19, (2010); Kronmuller H., Micromagnetism and the microstructure of ferromagnetic solids, (2003); Saavedra E., Corona R.M., Vidal-Silva N., Palma J.L., Altbir D., Escrig J., Dynamic and static properties of stadium-shaped antidot arrays, Scientific Reports, 10, 1, (2020)","N. Çam; Department of Physics, Dokuz Eylül University, Izmir, TR-35160, Turkey; email: necda.cam@ogr.deu.edu.tr","","Springer Science and Business Media B.V.","","","","","","13880764","","","","English","J. Nanopart. Res.","Article","Final","","Scopus","2-s2.0-85203860213" +"Jin X.-W.; Yang Z.-Y.; Liao Z.-M.; Jing G.; Yang W.-L.","Jin, Xin-Wei (57203688907); Yang, Zhan-Ying (7405433561); Liao, Zhi-Min (34974444500); Jing, Guangyin (10641698900); Yang, Wen-Li (7407757708)","57203688907; 7405433561; 34974444500; 10641698900; 7407757708","Unveiling stable one-dimensional magnetic solitons in magnetic bilayers","2024","Physical Review B","109","1","014414","","","","4","10.1103/PhysRevB.109.014414","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85182896664&doi=10.1103%2fPhysRevB.109.014414&partnerID=40&md5=8a2dcbd5fd9cd1acbdf700a90fc26582","School of Physics, Northwest University, Xi'an, 710127, China; Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China; School of Physics, Peking University, Beijing, 100871, China; Insititute of Physics, Northwest University, Xi'an, 710127, China","Jin X.-W., School of Physics, Northwest University, Xi'an, 710127, China, Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China; Yang Z.-Y., School of Physics, Northwest University, Xi'an, 710127, China, Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China; Liao Z.-M., School of Physics, Peking University, Beijing, 100871, China; Jing G., School of Physics, Northwest University, Xi'an, 710127, China; Yang W.-L., Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China, Insititute of Physics, Northwest University, Xi'an, 710127, China","We propose a novel model which efficiently describes the magnetization dynamics in a magnetic bilayer system. By applying a particular gauge transformation to the Landau-Lifshitz-Gilbert (LLG) equation, we successfully convert the model into an exactly integrable framework. Thus the obtained analytical solutions allow us to predict a one-dimensional magnetic soliton pair existing by tuning the thickness of the spacing layer between the two ferrimagnetic layers. The decoupling-unlocking-locking transition of soliton motion is determined at various interaction intensity. Our results have implications for the manipulation of magnetic solitons and the design of theoretical magnetic soliton-based distance detection prototype. © 2024 American Physical Society.","","Bilayer systems; Decouplings; Ferrimagnetics; Gauge transformation; Landau-Lifshitz-Gilbert equations; Magnetic bilayer; Magnetic solitons; Magnetization dynamics; One-dimensional; Soliton pairs; Solitons","","","","","National Natural Science Foundation of China, NSFC, (12174306, 12247103, 12275213); National Natural Science Foundation of China, NSFC; Natural Science Basic Research Program of Shaanxi Province, (2021JCW-19, 2023-JC-JQ-02); Natural Science Basic Research Program of Shaanxi Province","The authors thank Profs. H. Yu and C. Liu for their helpful discussions. This work was supported by the National Natural Science Foundation of China (Grants No. 12275213, No. 12174306, and No. 12247103), and Natural Science Basic Research Program of Shaanxi (Grants No. 2023-JC-JQ-02 and No. 2021JCW-19).","Kosevich A. M., Ivanov B., Kovalev A., Magnetic solitons, Phys. Rep, 194, (1990); Wang H., Yuan R., Zhou Y., Zhang Y., Chen J., Liu S., Jia H., Yu D., Ansermet J.-P., Song C., Long-Distance coherent propagation of high-velocity antiferromagnetic spin waves, Phys. Rev. Lett, 130, (2023); Liu C., Chen J., Liu T., Heimbach F., Yu H., Xiao Y., Hu J., Liu M., Chang H., Stueckler T., Long-distance propagation of short-wavelength spin waves, Nat. Commun, 9, (2018); Li C.-Z., Wang A.-Q., Li C., Zheng W.-Z., Brinkman A., Yu D.-P., Liao Z.-M., Topological transition of superconductivity in dirac semimetal nanowire josephson junctions, Phys. Rev. Lett, 126, (2021); Lan J., Yu W., Xiao J., Geometric magnonics with chiral magnetic domain walls, Phys. Rev. B, 103, (2021); Ohkuma M., Mito M., Kousaka Y., Tajiri T., Akimitsu J., Kishine J., Inoue K., Soliton locking phenomenon over finite magnetic field region in the monoaxial chiral magnet (Equation presented), Appl. Phys. Lett, 117, (2020); Zhang X., Zhou Y., Song K. M., Park T.-E., Xia J., Ezawa M., Liu X., Zhao W., Zhao G., Woo S., Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications, J. Phys.: Condens. Matter, 32, (2020); Gu K., Guan Y., Hazra B. K., Deniz H., Migliorini A., Zhang W., Parkin S. S., Three-dimensional racetrack memory devices designed from freestanding magnetic heterostructures, Nat. Nanotechnol, 17, (2022); Zhang H., Kang W., Wang L., Wang K. L., Zhao W., Stateful reconfigurable logic via a single-voltage-gated spin hall-effect driven magnetic tunnel junction in a spintronic memory, IEEE Trans. Electron Devices, 64, (2017); Tserkovnyak Y., Brataas A., Bauer G. E. W., Halperin B. I., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Rev. Mod. Phys, 77, (2005); Klingler S., Amin V., Geprags S., Ganzhorn K., Maier-Flaig H., Althammer M., Huebl H., Gross R., McMichael R. D., Stiles M. D., Spin-torque excitation of perpendicular standing spin waves in coupled YIG/Co heterostructures, Phys. Rev. Lett, 120, (2018); Gallardo R., Schneider T., Chaurasiya A., Oelschlagel A., Arekapudi S., Roldan-Molina A., Hubner R., Lenz K., Barman A., Fassbender J., Reconfigurable spin-wave nonreciprocity induced by dipolar interaction in a coupled ferromagnetic bilayer, Phys. Rev. Appl, 12, (2019); Slonczewski J. C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, (1996); Apalkov D., Khvalkovskiy A., Watts S., Nikitin V., Tang X., Lottis D., Moon K., Luo X., Chen E., Ong A., Spin-transfer torque magnetic random access memory (STT-MRAM), J. Emerg. Technol. Comput. 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B, 93, (2016)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85182896664" +"Taniguchi T.; Isogami S.; Okame S.; Nakada K.; Komura E.; Sasaki T.; Mitani S.; Hayashi M.","Taniguchi, Tomohiro (36180180300); Isogami, Shinji (9734646900); Okame, Shuji (58706836500); Nakada, Katsuyuki (57193068200); Komura, Eiji (57207883691); Sasaki, Tomoyuki (36085205900); Mitani, Seiji (35481829600); Hayashi, Masamitsu (10638890800)","36180180300; 9734646900; 58706836500; 57193068200; 57207883691; 36085205900; 35481829600; 10638890800","Probability of spin-orbit torque driven magnetization switching assisted by spin-transfer torque","2023","Physical Review B","108","13","134431","","","","2","10.1103/PhysRevB.108.134431","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85177614099&doi=10.1103%2fPhysRevB.108.134431&partnerID=40&md5=015856c5df1aade256e80383d1561aa8","National Institute of Advanced Industrial Science and Technology, Research Center for Emerging Computing Technologies, Ibaraki, Tsukuba, 305-8568, Japan; National Institute for Materials Science, Tsukuba, 305-0047, Japan; Advanced Products Development Center, Technology & Intellectual Property HQ, TDK Corporation, Chiba, Ichikawa, 272-8558, Japan; Department of Physics, The University of Tokyo, Tokyo, 113-8654, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology, Research Center for Emerging Computing Technologies, Ibaraki, Tsukuba, 305-8568, Japan; Isogami S., National Institute for Materials Science, Tsukuba, 305-0047, Japan; Okame S., Advanced Products Development Center, Technology & Intellectual Property HQ, TDK Corporation, Chiba, Ichikawa, 272-8558, Japan; Nakada K., Advanced Products Development Center, Technology & Intellectual Property HQ, TDK Corporation, Chiba, Ichikawa, 272-8558, Japan; Komura E., Advanced Products Development Center, Technology & Intellectual Property HQ, TDK Corporation, Chiba, Ichikawa, 272-8558, Japan; Sasaki T., Advanced Products Development Center, Technology & Intellectual Property HQ, TDK Corporation, Chiba, Ichikawa, 272-8558, Japan; Mitani S., National Institute for Materials Science, Tsukuba, 305-0047, Japan; Hayashi M., National Institute for Materials Science, Tsukuba, 305-0047, Japan, Department of Physics, The University of Tokyo, Tokyo, 113-8654, Japan","Spin-orbit torque (SOT) driven magnetization switching, assisted by spin-transfer torque (STT), enables field-free switching in ferromagnetic nanostructures and is expected to be a writing method for next-generation spintronic nonvolatile memory. The role of STT is to shift the magnetization pointing in an in-plane direction via the SOT to a different direction and ensure the switching. Here, we study the dependence of the switching probability on the STT strength using a numerical simulation of the Landau-Lifshitz-Gilbert (LLG) equation. While a monotonic increase of the switching probability with increasing STT strength is found in a relatively weak STT region, we find an unexpected increase in the error rate in a relatively large STT current close to a critical current. Based on the statistical analysis of the magnetization dynamics and solving the LLG equation analytically, we reveal that the origin of the switching error is the presence of an inactive region in the Bloch sphere where the magnetization dynamics becomes very slow compared with conventional SOT switching. Since this region exists far away from the initial state of the magnetization, a strong STT is necessary to reach the region. Accordingly, the switching error increases in a strong STT region. We also show that the issue can be solved by reducing the time only the STT is applied and/or enhancing the SOT strength. © 2023 American Physical Society.","","Errors; Magnetization; Ferromagnetic nanostructures; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetization switching; Non-volatile memory; Nonvolatile memory; Spin orbits; Spin transfer torque; Switching errors; Switching probability; Torque","","","","","TDK Corporation","This work was supported by funding from the TDK Corporation.","Liu L., Lee O. J., Gudmundsen T. J., Ralph D. C., Buhrman R. A., Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect, Phys. Rev. Lett, 109, (2012); Yu G., Upadhyaya P., Fan Y., Alzate J. G., Jiang W., Wong K. L., Takei S., Bender S. A., Chang L.-T., Jiang Y., Lang M., Tang J., Wang Y., Tserkovnyak Y., Amiri P. K., Wang K. L., Switching of a perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields, Nat. Nanotechnol, 9, (2014); Cubukcu M., Boulle O., Drouard M., Garello K., Avci C. O., Miron I. M., Langer J., Ocker B., Gambardella P., Gaudin G., Spin-orbit torque magnetization switching of a three-terminal perpendicular magnetic tunnel junction, Appl. Phys. Lett, 104, (2014); You L., Lee O., Bhowmik D., Labanowski D., Hong J., Bokor J., Salahuddin S., Switching of perpendicularly polarized nanomagnets with spin orbit torque without an external magnetic field by engineering a tilted anisotropy, Proc. Natl. Acad. Sci. USA, 112, (2015); Torrejon J., Garcia-Sanchez F., Taniguchi T., Sinha J., Mitani S., Kim J.-V., Hayashi M., Current-driven asymmetric magnetization switching in perpendicularly magnetized CoFeB/MgO heterostructures, Phys. Rev. B, 91, (2015); van den Brink A., Vermijs G., Solignac A., Koo J., Kohlhepp J. T., Swagten H. J. 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Nanotechnol, 11, (2016); Wang M., Cai W., Zhu D., Wang Z., Kan J., Zhao Z., Cao K., Wang Z., Zhang Y., Zhang T., Park C., Wang J.-P., Fert A., Zhao W., Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin-orbit and spin-transfer torques, Nat. Electron, 1, (2018); Grimaldi E., Krizakova V., Sala G., Yasin F., Couet S., Kar G. S., Garello K., Gambardella P., Single-shot dynamics of spin-orbit torque and spin transfer torque switching in three-terminal magnetic tunnel junctions, Nat. Nanotechnol, 15, (2020); Pathak S., Youm C., Hong J., Impact of spin-orbit torque on spin-transfer torque switching in magnetic tunnel junctions, Sci. Rep, 10, (2020); Zhang C., Takeuchi Y., Fukami S., Ohno H., Field-free and sub-ns magnetization switching of magnetic tunnel junctions by combining spin-transfer torque and spin-orbit torque, Appl. Phys. Lett, 118, (2021); Kang D. H., Shin M., Critical switching current density of magnetic tunnel junction with shape perpendicular magnetic anisotropy through the combination of spin-transfer and spin-orbit torques, Sci. Rep, 11, (2021); Sun J. Z., Robertazzi R. P., Nowak J., Trouilloud P. L., Hu G., Abraham D. W., Gaidis M. C., Brown S. L., O'Sullivan E. J., Gallagher W. J., Worledge D. C., Effect of subvolume excitation and spin-torque efficiency on magnetic switching, Phys. Rev. B, 84, (2011); Sun J. Z., Spin-torque switching efficiency in CoFeB-MgO based tunnel junctions, Phys. Rev. B, 88, (2013); Chaves-O'Flynn G. D., Wolf G., Sun J. Z., Kent A. D., Thermal stability of magnetic states in circular thin-film nanomagnets with large perpendicular magnetic anisotropy, Phys. Rev. Appl, 4, (2015); Sun J. Z., Spin-transfer torque switching probability of CoFeB/MgO/CoFeB magnetic tunnel junctions beyond macrospin, Phys. Rev. B, 104, (2021); Dyakonov M. I., Perel V. 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Phys, 56, (2017); Shiokawa Y., Komura E., Ishitani Y., Tsumita A., Suda K., Hamanaka K., Taniguchi T., Sasaki T., Dependency of high-speed write properties on external magnetic field in spin-orbit torque in-plane magnetoresistance devices, Appl. Phys. Express, 14, (2021); Slonczewski J. C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, (1996); Sun J. Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, 62, (2000); Taniguchi T., Yamada K., Nakatani Y., Critical current formula of perpendicularly magnetized magnetic random access memory revisited, Jpn. J. Appl. Phys, 58, (2019); Lee K.-S., Lee S.-W., Min B.-C., Lee K.-J., Theoretical current for switching of a perpendicular magnetic layer induced by spin Hall effect, Appl. Phys. Lett, 102, (2013); Morise H., Nakamura S., Relaxing-precessional magnetization switching, J. Magn. Magn. Mater, 306, (2006); Oogane M., Wakitani T., Yakata S., Yilgin R., Ando Y., Sakuma A., Miyazaki T., Magnetic damping in ferromagnetic thin films, Jpn. J. Appl. Phys, 45, (2006); Brown W. F., Thermal fluctuations of a single-domain particle, Phys. Rev, 130, (1963); Taniguchi T., Isogami S., Shiokawa Y., Ishitani Y., Komura E., Sasaki T., Mitani S., Hayashi M., Magnetization switching probability in the dynamical switching regime driven by spin-transfer torque, Phys. Rev. B, 106, (2022); Khvalkovskiy A. V., Apalkov D., Watts S., Chepulskii R., Beach R. S., Ong A., Tang X., Driskill-Smith A., Butler W. H., Visscher P. B., Lottis D., Chen E., Nikitin V., Krounbi M., Basic principles of STT-MRAM cell operation in memory arrays, J. Phys. D, 46, (2013); Apalkov D., Dieny B., Slaughter J. M., Magnetoresistive random access memory, Proc. IEEE, 104, (2016); Dieny B., Goldfarb R. B., Lee K.-J., Introduction to Magnetic Random-Access Memory, (2016)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85177614099" +"Wang M.; Yuan Y.; Jiang Y.","Wang, Manman (57221832033); Yuan, Yuhai (58673877900); Jiang, Yanfeng (17436165500)","57221832033; 58673877900; 17436165500","Realization of Artificial Neurons and Synapses Based on STDP Designed by an MTJ Device","2023","Micromachines","14","10","1820","","","","1","10.3390/mi14101820","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85175366508&doi=10.3390%2fmi14101820&partnerID=40&md5=8bf9e874a6be551590b5cd5b545129ad","Department of Electrical Engineering, School of Internet of Things (IoTs), Jiangnan University, Wuxi, 214122, China","Wang M., Department of Electrical Engineering, School of Internet of Things (IoTs), Jiangnan University, Wuxi, 214122, China; Yuan Y., Department of Electrical Engineering, School of Internet of Things (IoTs), Jiangnan University, Wuxi, 214122, China; Jiang Y., Department of Electrical Engineering, School of Internet of Things (IoTs), Jiangnan University, Wuxi, 214122, China","As the third-generation neural network, the spiking neural network (SNN) has become one of the most promising neuromorphic computing paradigms to mimic brain neural networks over the past decade. The SNN shows many advantages in performing classification and recognition tasks in the artificial intelligence field. In the SNN, the communication between the pre-synapse neuron (PRE) and the post-synapse neuron (POST) is conducted by the synapse. The corresponding synaptic weights are dependent on both the spiking patterns of the PRE and the POST, which are updated by spike-timing-dependent plasticity (STDP) rules. The emergence and growing maturity of spintronic devices present a new approach for constructing the SNN. In the paper, a novel SNN is proposed, in which both the synapse and the neuron are mimicked with the spin transfer torque magnetic tunnel junction (STT-MTJ) device. The synaptic weight is presented by the conductance of the MTJ device. The mapping of the probabilistic spiking nature of the neuron to the stochastic switching behavior of the MTJ with thermal noise is presented based on the stochastic Landau–Lifshitz–Gilbert (LLG) equation. In this way, a simplified SNN is mimicked with the MTJ device. The function of the mimicked SNN is verified by a handwritten digit recognition task based on the MINIST database. © 2023 by the authors.","image recognition; neuron; STT-MTJ; synapse","Character recognition; Image recognition; Neural networks; Stochastic systems; Tunnel junctions; Artificial neurons; Artificial synapse; Magnetic tunnel junction; Neural-networks; Spike timing dependent plasticities; Spin transfer torque; Spin transfer torque magnetic tunnel junction; Synapse; Synaptic weight; Third generation; Neurons","","","","","National Natural Science Foundation of China, NSFC, (61774078)","This work was supported by the National Natural Science Foundation of China (NSFC) with grant no. 61774078.","Diehl P.U., Cook M., Unsupervised learning of digit recognition using spike-timing-dependent plasticity, Front. Comput. Neurosci, 9, (2015); Wallace E., Benayoun M., van Drongelen W., Cowan J.D., Emergent Oscillations in Networks of Stochastic Spiking Neurons, PLoS ONE, 6, (2011); Ikegawa S., Mancoff F.B., Janesky J., Aggarwal S., Magnetoresistive Random Access Memory: Present and Future, IEEE Trans. Electron Devices, 67, pp. 1407-1419, (2020); Kang S.H., Park C., MRAM: Enabling a sustainable device for pervasive system architectures and applications, Proceedings of the 2017 IEEE International Electron Devices Meeting (IEDM); Montoya E.A., Chen J.-R., Ngelale R., Lee H.K., Tseng H.-W., Wan L., Yang E., Braganca P., Boyraz O., Bagherzadeh N., Et al., Immunity of nanoscale magnetic tunnel junctions with perpendicular magnetic anisotropy to ionizing radiation, Sci. Rep, 10, (2020); Li S., Jiang Y., Nanoscale Thermal Transport Model of Magnetic Tunnel Junction (MTJ) device for STT-MRAM, IEEE Trans. Magn, 58, (2022); Vincent A.F., Larroque J., Locatelli N., Ben Romdhane N., Bichler O., Gamrat C., Zhao W.S., Klein J.-O., Galdin-Retailleau S., Querlioz D., Spin-Transfer Torque Magnetic Memory as a Stochastic Memristive Synapse for Neuromorphic Systems, IEEE Trans. Biomed. Circuits Syst, 9, pp. 166-174, (2015); Yang A., Jiang Z., Huang Z., Zhang Z., Jiang Y., Double-Ended Superposition Anti-Noise Resistance Monitoring Write Termination Scheme for Reliable Write Operation in STT-MRAM, IEEE Trans. Circuits Syst. I Regul. Pap, 70, pp. 1147-1160, (2023); Yang A., Jiang Y., Leakage-Current-Canceling Current-Sampling Sense Amplifier for Deep Submicrometer STT-RAM, IEEE Trans. Circuits Syst. II Express Briefs, 69, pp. 3874-3878, (2022); Sengupta A., Panda P., Wijesinghe P., Kim Y., Roy K., Magnetic Tunnel Junction Mimics Stochastic Cortical Spiking Neurons, Sci. Rep, 6, (2016); Zhang G., Jiang Y., Fast Writing Strategy of STT-MRAM With Pipeline Architecture, IEEE Trans. Magn, 58, (2022); Sengupta A., Banerjee A., Roy K., Hybrid Spintronic-CMOS Spiking Neural Network with On-Chip Learning: Devices, Circuits, and Systems, Phys. Rev. Appl, 6, (2016); Srinivasan G., Sengupta A., Roy K., Magnetic Tunnel Junction Based Long-Term Short-Term Stochastic Synapse for a Spiking Neural Network with On-Chip STDP Learning, Sci. Rep, 6, (2016); Zhang X., Zhang G., Shen L., Yu P., Jiang Y., Life-time degradation of STT-MRAM by self-heating effect with TDDB model, Solid-State Electron, 173, (2020); Wang M., Jiang Y., Compact model of nanometer STT-MTJ device with scale effect, AIP Adv, 11, (2021); Pan G., Karymy A., Yu P., Jiang Y., Novel Low Noise Amplifier for Neural Signals Based on STT-MTJ Spintronic Device, IEEE Access, 7, pp. 145641-145650, (2019); Su H., Jiang Y., Voltage-Controlled Magnetic Tunnel Junctions Enabled Low-Power Feature Extractor, IEEE Electron Device Lett, 43, pp. 1858-1861, (2022); Wang M., Jiang Y., MPT Tool: A Parameter Extraction Tool for Accurate Modeling of Magnetic Tunnel Junction Devices, IEEE J. Electron Devices Soc, 10, pp. 833-842, (2022); Deng J., Miriyala V.P.K., Zhu Z., Fong X., Liang G., Voltage-Controlled Spintronic Stochastic Neuron for Restricted Boltzmann Machine with Weight Sparsity, IEEE Electron Device Lett, 41, pp. 1102-1105, (2020); Sengupta A., Roy K., Short-Term Plasticity and Long-Term Potentiation in Magnetic Tunnel Junctions: Towards Volatile Synapses, Phys. Rev. Appl, 5, (2016); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Physik. Z. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev, 100, (1995); Slonczewski J., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, pp. L1-L7, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B Condens. Matter, 54, (1996); Vatankhahghadim A., Huda S., Sheikholeslami A., A Survey on Circuit Modeling of Spin-Transfer-Torque Magnetic Tunnel Junctions, IEEE Trans. Circuits Syst. I Regul. Pap, 61, pp. 2634-2643, (2014); Wang M., Cai W., Zhu D., Wang Z., Kan J., Zhao Z., Cao K., Wang Z., Zhang Y., Zhang T., Et al., Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin–orbit and spin-transfer torques, Nat. Electron, 1, pp. 582-588, (2018); Lecun Y., Bottou L., Bengio Y., Haffner P., Gradient-based learning applied to document recognition, Proc. IEEE, 86, pp. 2278-2324, (1998); Benayoun M., Cowan J.D., Van Drongelen W., Wallace E., Avalanches in a stochastic model of spiking neurons Supporting Information, PLoS Comput. Biol, 6, (2010)","Y. Jiang; Department of Electrical Engineering, School of Internet of Things (IoTs), Jiangnan University, Wuxi, 214122, China; email: jiangyf@jiangnan.edu.cn","","Multidisciplinary Digital Publishing Institute (MDPI)","","","","","","2072666X","","","","English","Micromachines","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85175366508" +"Gong B.; Wei C.; Yang H.; Yu Z.; Wang L.; Xiong L.; Xiong R.; Lu Z.; Zhang Y.; Liu Q.","Gong, Bin (57321683800); Wei, Chenhuinan (57191611866); Yang, Han (58115696300); Yu, Ziyang (57195288051); Wang, Luowen (58115311900); Xiong, Lun (55210315300); Xiong, Rui (57216372992); Lu, Zhihong (36915311400); Zhang, Yue (57218772783); Liu, Qingbo (57196046069)","57321683800; 57191611866; 58115696300; 57195288051; 58115311900; 55210315300; 57216372992; 36915311400; 57218772783; 57196046069","Control and regulation of skyrmionic topological charge in a novel synthetic antiferromagnetic nanostructure","2023","Nanoscale","15","11","","5257","5264","7","2","10.1039/d2nr06498g","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85148743605&doi=10.1039%2fd2nr06498g&partnerID=40&md5=0299d88cca876da205b90d24f5f80b27","Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan, 430068, China; Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, China; The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan, 430081, China; School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China","Gong B., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Wei C., Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan, 430068, China; Yang H., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Yu Z., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Wang L., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Xiong L., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; Xiong R., Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, China; Lu Z., The State Key Laboratory of Refractories and Metallurgy, School of Materials and Metallurgy, Wuhan University of Science and Technology, Wuhan, 430081, China; Zhang Y., School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China; Liu Q., Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China","Skyrmionium is a combination of a skyrmion with a topological charge (Q is +1 or −1), resulting in a magnetic configuration with a total topological charge of Q = 0. Skyrmionium has distinctive characteristics, including a slightly higher velocity, motion restricted to the middle of the track without the skyrmion Hall effect (SkHE), and absence of an acceleration phase. However, there is little stray field due to the zero net magnetization, the topological charge Q is zero due to the magnetic configuration, and detecting skyrmionium is still challenging. In the present work, we propose a novel nanostructure composed of triple nanowires with a narrow channel. It was found that the skyrmionium is converted into a DW pair or skyrmion by the concave channel. It was also found that the topological charge Q can be regulated by Ruderman-Kittel-Kasuya-Yosida (RKKY) antiferromagnetic (AFM) exchange coupling. Moreover, we analyzed the mechanism of the function based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation and constructed a deep spiking neural network (DSNN) with a recognition accuracy of 98.6% with supervised learning via the spike timing dependent plasticity rule (STDP) by considering the nanostructure as an artificial synapse device corresponding to the electrical properties of the nanostructure. These results provide the means for skyrmion-skyrmionium hybrid application and neuromorphic computing applications. © 2023 The Royal Society of Chemistry.","","Antiferromagnetism; Deep neural networks; Neurons; Topology; Acceleration phase; Antiferromagnetic exchange coupling; High velocity; Magnetic configuration; Narrow channel; Ruderman-Kittel-Kasuya-Yosida; Skyrmions; Stray field; Synthetic antiferromagnetic; Topological charges; Nanostructures","","","","","Graduate Innovative Fund of Wuhan Institute of Technology, (CX2021376, CX2021388); National Natural Science Foundation of China, NSFC, (11804211, 12104348, 51971098, 52201213, 91963207); National Natural Science Foundation of China, NSFC; Department of Science and Technology, Hubei Provincial People's Government, (2019CFB435); Department of Science and Technology, Hubei Provincial People's Government; National Key Research and Development Program of China, NKRDPC, (2022YFE0103300); National Key Research and Development Program of China, NKRDPC","The authors acknowledge financial support from the National Key Research and Development Program of China (No. 2022YFE0103300), the National Natural Science Foundation of China (No. 12104348, 51971098, 52201213, and 11804211), the Major Research plan of the National Natural Science Foundation of China (No. 91963207), the Science and Technology Department of Hubei Province (No. 2019CFB435), and the Graduate Innovative Fund of Wuhan Institute of Technology (No. CX2021376 and CX2021388).","Yu X., Onose Y., Kanazawa N., Park J.H., Han J., Matsui Y., Nagaosa N., Tokura Y., Nature, 465, pp. 901-904, (2010); Dzyaloshinsky I., J. Phys. Chem. Solids, 4, pp. 241-255, (1958); Fert A., Cros V., Sampaio J., Nat. Nanotechnol., 8, pp. 152-156, (2013); Jiang W., Zhang X., Yu G., Zhang W., Wang X., Benjamin Jungfleisch M., Pearson J.E., Cheng X., Heinonen O., Wang K.L., Nat. Phys., 13, pp. 162-169, (2017); Zang J., Mostovoy M., Han J.H., Nagaosa N., Phys. Rev. Lett., 107, (2011); Litzius K., Lemesh I., Kruger B., Bassirian P., Caretta L., Richter K., Buttner F., Sato K., Tretiakov O.A., Forster J., Nat. Phys., 13, pp. 170-175, (2017); Komineas S., Papanicolaou N., Phys. Rev. B: Condens. Matter Mater. Phys., 92, (2015); Woo S., Song K.M., Zhang X., Zhou Y., Ezawa M., Liu X., Finizio S., Raabe J., Lee N.J., Kim S.-I., Nat. Commun., 9, pp. 1-8, (2018); Schaffer A.F., Durr H.A., Berakdar J., Appl. Phys. Lett., 111, (2017); Zhang X., Xia J., Zhou Y., Wang D., Liu X., Zhao W., Ezawa M., Phys. Rev. B, 94, (2016); Li S., Xia J., Zhang X., Ezawa M., Kang W., Liu X., Zhou Y., Zhao W., Appl. Phys. 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Mater., 491, (2019); Li S., Kang W., Huang Y., Zhang X., Zhou Y., Zhao W., Nanotechnology, 28, (2017); Huang Y., Kang W., Zhang X., Zhou Y., Zhao W., Nanotechnology, 28, (2017); Wang X., Yang Q., Wang L., Zhou Z., Min T., Liu M., Sun N.X., Adv. Mater., 30, (2018); Yu Z., Gong B., Wei C., Wang R., Xiong L., You L., Zhang Y., Liang S., Lu Z., Xiong R., Appl. Phys. Lett., 121, (2022); Liu X., Deng Y., Lan X., Li R., Wang K., Sci. China: Phys., Mech. Astron., 64, pp. 1-8, (2021); Rohart S., Thiaville A., Phys. Rev. B: Condens. Matter Mater. Phys., 88, (2013); Sampaio J., Cros V., Rohart S., Thiaville A., Fert A., Nat. Nanotechnol., 8, pp. 839-844, (2013); Zhou Y., Iacocca E., Awad A.A., Dumas R.K., Zhang F., Braun H.B., Akerman J., Nat. Commun., 6, pp. 1-10, (2015); Zhou Y., Ezawa M., Nat. Commun., 5, pp. 1-8, (2014); Woo S., Mann M., Tan A.J., Caretta L., Beach G.S., Appl. Phys. Lett., 105, (2014); Nagaosa N., Tokura Y., Nat. Nanotechnol., 8, pp. 899-911, (2013); Gobel B., Schaffer A.F., Berakdar J., Mertig I., Parkin S.S., Sci. Rep., 9, pp. 1-9, (2019); Iwasaki J., Koshibae W., Nagaosa N., Nano Lett., 14, pp. 4432-4437, (2014); Iwasaki J., Mochizuki M., Nagaosa N., Nat. Nanotechnol., 9, pp. 156-156, (2014); Stosic D., Ludermir T.B., Milosevic M.V., Phys. Rev. B, 96, (2017); Muller J., Rosch A., Phys. Rev. B: Condens. Matter Mater. Phys., 91, (2015); Fang W., Chen Y., Ding J., Chen D., Yu Z., Zhou H., Tian Y., Spikingjelly, 9, (2020); Diehl P.U., Cook M., Front. Comput. Neurosci., 9, (2015); Prezioso M., Mahmoodi M., Bayat F.M., Nili H., Kim H., Vincent A., Strukov D., Nat. Commun., 9, pp. 1-8, (2018)","Z. Yu; Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; email: tommyu91@163.com; Q. Liu; Hubei Key Laboratory of Optical Information and Pattern Recognition, School of Optical Information and Energy Engineering, Wuhan Institute of Technology, Wuhan, 430205, China; email: phyqboliu@wit.edu.cn","","Royal Society of Chemistry","","","","","","20403364","","","36794971","English","Nanoscale","Article","Final","","Scopus","2-s2.0-85148743605" +"He J.; Yang L.; Zhan J.","He, Jiayun (59004817600); Yang, Lei (59043156600); Zhan, Jiajun (57222157503)","59004817600; 59043156600; 57222157503","Temporal High-Order Accurate Numerical Scheme for the Landau–Lifshitz–Gilbert Equation","2024","Mathematics","12","8","1179","","","","1","10.3390/math12081179","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85191455844&doi=10.3390%2fmath12081179&partnerID=40&md5=53b661f2ac1d7f7d29554dd2c4047146","School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao","He J., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao; Yang L., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao; Zhan J., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao","In this paper, a family of temporal high-order accurate numerical schemes for the Landau–Lifshitz–Gilbert (LLG) equation is proposed. The proposed schemes are developed utilizing the Gauss–Legendre quadrature method, enabling them to achieve arbitrary high-order time discretization. Furthermore, the geometrical properties of the LLG equation, such as the preservation of constant magnetization magnitude and the Lyapunov structure, are investigated based on the proposed discrete schemes. It is demonstrated that the magnetization magnitude remains constant with an error of (Formula presented.) order in time when utilizing a (Formula presented.) th-order discrete scheme. Additionally, the preservation of the Lyapunov structure is achieved with a second-order error in the temporal step size. Numerical experiments and simulations effectively verify the performance of our proposed algorithm and validate our theoretical analysis. © 2024 by the authors.","Gauss–Legendre quadrature; geometric property; Landau–Lifshitz–Gilbert equation; micromagnetics","","","","","","Fundo para o Desenvolvimento das Ciências e da Tecnologia, FDCT; Macau, (0031/2022/A1); Macau University of Science and Technology, MUST, (FRG 22-021-FI); Macau University of Science and Technology, MUST","This work is partially supported by the Science and Technology Development Fund, Macau SAR (Grant No. 0031/2022/A1), and the MUST Faculty Research Grants (FRG 22-021-FI).","Baibich M.N., Broto J.M., Fert A., Van Dau F.N., Petroff F., Etienne P., Creuzet G., Friederich A., Chazelas J., Giant magnetoresistance of (001) Fe/(001) Cr magnetic superlattices, Phys. Rev. Lett, 61, (1988); Binasch G., Grunberg P., Saurenbach F., Zinn W., Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange, Phys. Rev. B, 39, (1989); Wang D., Tondra M., Pohm A.V., Nordman C., Anderson J., Daughton J.M., Black W.C., Spin dependent tunneling devices fabricated for magnetic random access memory applications using latching mode, J. Appl. Phys, 87, pp. 6385-6387, (2000); Lnu S., Magnetoresistive Random Access Memory (MRAM) Technology: Current Advancement and Future Development, Ph.D. Thesis, (2010); Aharoni A., Introduction to the Theory of Ferromagnetism, 109, (2000); Bertotti G., Serpico C., Mayergoyz I.D., Nonlinear magnetization dynamics under circularly polarized field, Phys. Rev. Lett, 86, (2001); Kikuchi R., On the minimum of magnetization reversal time, J. Appl. Phys, 27, pp. 1352-1357, (1956); Mallinson J.C., Damped gyromagnetic switching, IEEE Trans. Magn, 36, pp. 1976-1981, (2000); Serpico C., Mayergoyz I.D., Bertotti G., Analytical solutions of Landau–Lifshitz equation for precessional switching, J. Appl. Phys, 93, pp. 6909-6911, (2003); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Method Eng, 15, pp. 1-37, (2007); Garcia-Cervera C.J., Numerical micromagnetics: A review, Bol. Soc. Esp. Mat. Apl, 39, pp. 103-136, (2007); Fidler J., Schrefl T., Micromagnetic modelling-the current state of the art, J. Phys. D Appl. Phys, 33, (2000); Yang L., Chen J., Hu G., A framework of the finite element solution of the Landau-Lifshitz-Gilbert equation on tetrahedral meshes, J. Comput. Phys, 431, (2021); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the Landau-Lifshitz-Gilbert equation for micromagnetics, Jpn. J. Appl. Phys, 28, (1989); Li P., Yang L., Lan J., Du R., Chen J., A second-order semi-implicit method for the inertial Landau-Lifshitz-Gilbert equation, Numer. Math. Theor. Meth. Appl, 16, pp. 182-203, (2023); Liu C.S., Lie symmetry of the Landau-Lifshitz-Gilbert equation and exact linearization in the Minkowski space, J. Math. Phys, 55, pp. 606-625, (2004); Garcia-Cervera C.J., E W., Improved Gauss-Seidel projection method for micromagnetics simulations, IEEE Trans. Magn, 39, pp. 1766-1770, (2003); Wang X., Garcia-Cervera C.J., E W., A Gauss–Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, pp. 357-372, (2001); Krishnaprasad P.S., Tan X., Cayley transforms in micromagnetics, Phys. B Condens. Matter, 306, pp. 195-199, (2001); Lewis D., Nigam N., Geometric integration on spheres and some interesting applications, J. Comput. Appl. Math, 151, pp. 141-170, (2003); d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau–Lifshitz–Gilbert equation based on the mid-point rule, J. Comput. Phys, 209, pp. 730-753, (2005); Spargo A.W., Ridley P.H.W., Roberts G.W., Geometric integration of the Gilbert equation, J. Appl. Phys, 93, pp. 6805-6807, (2003); Joly P., Vacus O., Mathematical and numerical studies of non linear ferromagnetic materials, ESAIM-Math. Model. Numer. Anal, 33, pp. 593-626, (1999); Monk P.B., Vacus O., Accurate discretization of a non-linear micromagnetic problem, Comput. Meth. Appl. Mech. Eng, 190, pp. 5243-5269, (2001); d'Aquino M., Serpico C., Miano G., Mayergoyz I.D., Bertotti G., Numerical integration of Landau–Lifshitz–Gilbert equation based on the midpoint rule, J. Appl. Phys, 97, (2005); Fuwa A., Ishiwata T., Tsutsumi M., Finite difference scheme for the Landau–Lifshitz equation, Jpn. J. Ind. Appl. Math, 29, pp. 83-110, (2012); Shepherd D., Miles J., Heil M., Mihajlovic M., An adaptive step implicit midpoint rule for the time integration of Newton’s linearisations of non-linear problems with applications in micromagnetics, J. Sci. Comput, 80, pp. 1058-1082, (2019); Zhan J., Yang L., Du R., Cui Z., Towards preserving geometric properties of Landau-Lifshitz-Gilbert equation using multistep methods, Commun. Comput. Phys, (2024); Akrivis G., Feischl M., Kovacs B., Lubich C., Higher-order linearly implicit full discretization of the Landau–Lifshitz–Gilbert equation, Math. Comput, 90, pp. 995-1038, (2021); Huang Z., High accuracy numerical method of thin-film problems in micromagnetics, J. Comput. Math, 21, pp. 33-40, (2003); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, pp. 3443-3449, (2004); Prohl A., Computational Micromagnetism, (2001); Stoer J., Bulirsch R., Introduction to Numerical Analysis, 12, (2002); Shen J., Tang T., Wang L.L., Spectral Methods: Algorithms, Analysis and Applications, 41, (2011); Donahue M.J., Porter D.G., OOMMF User’s Guide, Version 1.0, (1999)","L. Yang; School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao; email: leiyang@must.edu.mo","","Multidisciplinary Digital Publishing Institute (MDPI)","","","","","","22277390","","","","English","Mathematics","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85191455844" +"Li S.; Jiang Y.","Li, Shaomin (58374253600); Jiang, Yanfeng (17436165500)","58374253600; 17436165500","Field-free switching model of spin-orbit torque (SOT)-MTJ device with thermal effect based on voltage-controlled magnetic anisotropy (VCMA)","2023","AIP Advances","13","2","025030","","","","5","10.1063/9.0000426","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85147793079&doi=10.1063%2f9.0000426&partnerID=40&md5=4d34348ba8ccd57a1ca3d271f13d67a1","Department of Electrical Engineering, School of Internet of Things (IoTs), Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, China","Li S., Department of Electrical Engineering, School of Internet of Things (IoTs), Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, China; Jiang Y., Department of Electrical Engineering, School of Internet of Things (IoTs), Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, China","Electrically driven magnetization switch has attracted much attention in the new spintronic memory, especially for spin-orbit torque (SOT)-based magnetic random access memory (MRAM). However, the published models are facing limitations with the continuous shrinkage of the feature size down to nanoscale. Also, the thermal effect caused by switching operation is non-negligible. Therefore, an effective model is needed to represent the switching dynamic of the device concerning the influences of the nanoscale and the thermal effect. In the paper, a compact model of three-terminal SOT-driven switching is established. The influence of the voltage-controlled magnetic anisotropy (VCMA) and spin transfer torque (STT) effect induced by bias voltage on the field-free SOT-driven switching is considered by numerically solving the LLG equations. Furthermore, a 3D model of the SOT-MTJ device is established by finite element method to trace the thermoelectric behavior inside the device. The thermoelectric behavior is integrated into the compact model to show the influence of the temperature on the switching behavior, highlighting the importance of the thermal effect for the realistic modelling of SOT-driven switching. Finally, a novel voltage pulse scheme is proposed, which can effectively shorten the switching time and improve the reliability of the device. The established model could provide strategies and guidelines for next-generation memory design and application. © 2023 Author(s).","","3D modeling; Finite element method; Magnetic anisotropy; MRAM devices; Nanotechnology; Compact model; Feature sizes; Magnetic random access memory; Nano scale; Spin orbits; Switching model; Switching operations; Thermoelectric; Torque-based; Voltage-controlled; Trace elements","","","","","National Natural Science Foundation of China, NSFC, (61774078)","This work was supported by NSFC (No. 61774078). ","Apalkov D., Dieny B., Slaughter J.M., Magnetoresistive random access memory, Proc. IEEE, 104, pp. 1796-1830, (2016); Siracusano G., Tomasello R., D'Aquino M., Puliafito V., Giordano A., Azzerboni B., Braganca P., Finocchio G., Carpentieri M., Description of statistical switching in perpendicular STT-MRAM within an analytical and numerical micromagnetic framework, IEEE Trans. Magn., 54, pp. 1-10, (2018); Cubukcu M., Boulle O., Mikuszeit N., Hamelin C., Bracher T., Lamard N., Cyrille M., Buda-Prejbeanu L., Garello K., Et al., Ultra-fast perpendicular spin-orbit torque MRAM, IEEE Trans. Magn., 54, (2018); Liu L., Pai C.-F., Li Y., Tseng H.W., Ralph D.C., Buhrman R.A., Spin-torque switching with the giant spin Hall effect of tantalum, Science, 336, pp. 555-558, (2012); Cai W., Shi K., Zhuo Y., Zhu D., Huang Y., Yin J., Cao K., Wang Z., Guo Z., Wang Z., Wang G., Zhao W., Sub-ns field-free switching in perpendicular magnetic tunnel junctions by the interplay of spin transfer and orbit torques, IEEE Electron Device Lett., 42, pp. 704-707, (2021); Luo Z.Y., Tsou Y.J., Dong Y.C., Lu C., Liu C.W., Field-free spin-orbit torque switching of perpendicular magnetic tunnel junction utilizing voltage-controlled magnetic anisotropy pulse width optimization, 2018 Non-Volatile Memory Technology Symposium (NVMTS), (2018); Kang W., Ran Y., Zhang Y., Lv W., Zhao W., Zhao W.S., Modeling and exploration of the voltage-controlled magnetic anisotropy effect for the next-generation low-power and high-speed MRAM applications, IEEE Transactions on Nanotechnology, 16, pp. 387-395, (2017); Yoshida C., Tanaka T., Ataka T., Hoshina M., Furuya A., Field-free reliable magnetization switching in a three-terminal perpendicular magnetic tunnel junction via spin-orbit torque, spin-transfer torque, and voltage-controlled magnetic anisotropy, J. Phys. D: Appl. Phys., 55, (2022); Wang M., Cai W., Zhu D., Wang Z., Kan J., Zhao Z., Cao K., Wang Z., Zhang Y., Zhang T., Park C., Wang J.-P., Fert A., Zhao W., Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin orbit and spin-transfer torques, Nature Electron., 1, pp. 582-588, (2018); Li D., Yun J., Chen S., Cui B., Guo X., Wu K., Zuo Y., Yang D., Wang J., Xi L., Joule heating and temperature effects on current-induced magnetization switching in perpendicularly magnetized Pt/Co/C structures, J. Phys. D: Appl. Phys., 51, (2018); Krizakova V., Grimaldi E., Garello K., Sala G., Couet S., Kar G.S., Gambardella P., Interplay of voltage control of magnetic anisotropy, spin-transfer torque and heat in the spin-orbit-torque switching of three-terminal magnetic tunnel junctions, Physical Review Applied, 15, (2021); Wang M., Jiang Y., MPT tool: A parameter extraction tool for accurate modeling of magnetic tunnel junction devices, IEEE J. Electron Devices Soc., 10, pp. 833-842, (2022); Wang S., Lee H., Ebrahimi F., Amiri P.K., Wang K.L., Gupta P., Comparative evaluation of spin-transfer-torque and magnetoelectric random access memory, IEEE J. Emerg. Select. Top. Circ. Syst., 6, pp. 134-145, (2016); Zhang K., Zhang D., Wang C., Zeng L., Wang Y., Zhao W., Compact modeling and analysis of voltage-gated spin-orbit torque magnetic tunnel junction, IEEE Access, 8, pp. 50792-50800, (2020); Garello K., Yasin F., Couet S., Souriau L., Swerts J., Rao S., Van Beek S., Kim W., Liu E., Kundu S., Tsvetanova D., Jossart N., Croes K., Grimaldi E., Baumgartner M., Crotti D., Furnemont A., Gambardella P., Kar G.S., SOT-MRAM 300 mm integration for low power and ultrafast embedded memories, 2018 IEEE Sym VLSI Circuits, (2018); Shreya S., Kaushik B.K., Modeling of voltage-controlled spin-orbit torque MRAM for multilevel switching application, IEEE Trans. Electron Devices, 67, pp. 90-98, (2020); Teso B., Siritaratiwat A., Surawanitkun C., Different effect of temperature increment on CoFeB/MgO based single and double barrier magnetic tunnel junctions during switching process in STT-MRAM, 15th International Conference on Electrical Engineering/Electronics Computer Telecommunications and Information Technology (ECTI-CON), (2018); Zhang X., Zhang G., Shen L., Yu P., Jiang Y., Life-time degradation of STT-MRAM by self-heating effect with TDDB model, Solid State Electronics, 173, (2020); Goto M., Wakatake Y., Oji U.K., Miwa S., Strelkov N., Dieny B., Kubota H., Yakushiji K., Fukushima A., Yuasa S., Suzuki Y., Microwave amplification in a magnetic tunnel junction induced by heat-to-spin conversion at the nanoscale, Nat. Nanotechnol., 14, pp. 40-43, (2018); Lee K.-M., Choi J.W., Sok J., Min B.-C., Temperature dependence of the interfacial magnetic anisotropy in W/CoFeB/MgO, AIP Adv., 7, (2017); Wu Y.C., Kim W., Van Beek S., Couet S., Carpenter R., Rao S., Kundu S., Van Houdt J., Groeseneken G., Crotti D., Kar G.S., Impact of ambient temperature on the switching of voltage-controlled perpendicular magnetic tunnel junction, Appl. Phys. Lett., 118, (2021)","Y. Jiang; Department of Electrical Engineering, School of Internet of Things (IoTs), Institute of Advanced Technology, Jiangnan University, Wuxi, 214122, China; email: jiangyf@jiangnan.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85147793079" +"Ai F.; Lin Z.; Duan J.; Lomakin V.","Ai, Fangzhou (58777474500); Lin, Zhuonan (57191587782); Duan, Jiawei (58623889100); Lomakin, Vitaliy (35570326300)","58777474500; 57191587782; 58623889100; 35570326300","Periodic phase diagrams in micromagnetics with an eigenvalue solver","2025","IEEE Transactions on Magnetics","","","","","","","0","10.1109/TMAG.2025.3535711","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85216640140&doi=10.1109%2fTMAG.2025.3535711&partnerID=40&md5=5d8c76f2a60689706bf1b4c6fd65fd4d","University of California, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States; University of California, Center for Memory and Recording Research, San Diego, 92093, CA, United States; University of California, Program in Materials Science and Engineering, San Diego, 92093, United States","Ai F., University of California, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States, University of California, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Lin Z., University of California, Center for Memory and Recording Research, San Diego, 92093, CA, United States, University of California, Program in Materials Science and Engineering, San Diego, 92093, United States; Duan J., University of California, Center for Memory and Recording Research, San Diego, 92093, CA, United States, University of California, Program in Materials Science and Engineering, San Diego, 92093, United States; Lomakin V., University of California, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States, University of California, Center for Memory and Recording Research, San Diego, 92093, CA, United States, University of California, Program in Materials Science and Engineering, San Diego, 92093, United States","This work introduces an approach to compute periodic phase diagram of micromagnetic systems by solving a periodic linearized Landau-Lifshitz-Gilbert (LLG) equation using an eigenvalue solver with the Finite Element Method formalism. The linear operator in the eigenvalue problem is defined as a function of the periodic phase-shift wave vector. The dispersion diagrams are obtained by solving the eigenvalue problem for complex eigenfrequencies and corresponding eigenstates for a range of prescribed wave vectors. The presented approach incorporates a calculation of the periodic effective field, including the exchange and magnetostatic field components. The approach is general in that it allows 3D problems to be handled with any 1D, 2D, and 3D periodicities. The ability to calculate periodic diagrams provides insights into the spin wave propagation and localized resonances in complex micromagnetic structures. © 1965-2012 IEEE.","eigenvalue solver; micromagnetics; Periodic phase diagram","","","","","","","","Lin Z., Lomakin V., Linearized frequency domain Landau-Lifshitz-Gilbert equation formulation, AIP Advances, 13, 1, (2023); Wang W., Mu C., Zhang B., Liu Q., Wang J., Xue D., Two-dimensional periodic boundary conditions for demagnetization interactions in micromagnetics, Computational Materials Science, 49, 1, pp. 84-87, (2010); Bruckner F., Ducevic A., Heistracher P., Abert C., Suess D., Strayfield calculation for micromagnetic simulations using true periodic boundary conditions, Scientific Reports, 11, 1, (2021); Wysocki A.L., Antropov V.P., Micromagnetic simulations with periodic boundary conditions: Hard-soft nanocomposites, Journal of Magnetism and Magnetic Materials, 428, pp. 274-286, (2017); Dmytriiev O., Kruglyak V.V., Franchin M., Fangohr H., Giovannini L., Montoncello F., Role of boundaries in micromagnetic calculations of magnonic spectra of arrays of magnetic nanoelements, Phys. Rev. B, 87, (2013); Vukadinovic N., Vacus, Labrune M., Acher, Pain D., Magnetic excitations in a weak-stripe-domain structure: A 2d dynamic micromagnetic approach, Phys. Rev. Lett., 85, pp. 2817-2820, (2000); Asti G., Solzi M., Ghidini M., Neri F.M., Micromagnetic analysis of exchange-coupled hard-soft planar nanocomposites, Phys. Rev. B, 69, (2004); Pellicelli R., Solzi M., Pernechele C., Ghidini M., Continuum micromagnetic modeling of antiferromagnetically exchange-coupled multilayers, Phys. Rev. B, 83, (2011); Ralph D., Stiles M., Spin transfer torques, Journal of Magnetism and Magnetic Materials, 320, 7, pp. 1190-1216, (2008); Shao Q., Li P., Liu L., Yang H., Fukami S., Razavi A., Wu H., Wang K., Freimuth F., Mokrousov Y., Et al., Roadmap of spin–orbit torques, IEEE transactions on magnetics, 57, 7, pp. 1-39, (2021); Hrkac G., Kirschner M., Dorfbauer F., Suess D., Ertl O., Fidler J., Schrefl T., Three-dimensional micromagnetic finite element simulations including eddy currents, Journal of applied physics, 97, 10, (2005); Andra W., Berkov D., Mattheis R., Stress coupled phenomena: Magnetostriction, Encyclopedia of Materials: Science and Technology, pp. 8892-8894, (2001); Lin Z., Volvach I., Wang X., Lomakin V., Eigenvalue-based micromagnetic analysis of switching in spin-torque-driven structures, Phys. Rev. Appl., 17, (2022); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: Fast micromagnetic simulator for complex magnetic structures (invited), Journal of Applied Physics, 109, 7, (2011); Livshitz B., Boag A., Bertram H.N., Lomakin V., Nonuniform grid algorithm for fast calculation of magnetostatic interactions in micromagnetics, Journal of Applied Physics, 105, 7, (2009); Duan J., Wang X., Lomakin V., Hybrid superposition integral—poisson solver method for the magnetostatic field in finite element micromagnetic solvers, IEEE Transactions on Magnetics, 59, 11, pp. 1-5, (2023); Ai F., Lomakin V., Fast fourier transform periodic interpolation method for superposition sums in a periodic unit cell, Computer Physics Communications, (2024); Li S., Van Orden D.A., Lomakin V., Fast periodic interpolation method for periodic unit cell problems, IEEE Transactions on Antennas and Propagation, 58, 12, pp. 4005-4014, (2010); Van Orden D., Lomakin V., Rapidly convergent representations for 2d and 3d green’s functions for a linear periodic array of dipole sources, IEEE Transactions on Antennas and Propagation, 57, 7, pp. 1973-1984, (2009); Stancil D.D., Prabhakar A., Spin waves: Theory and Applications, (2009); Ai F., Duan J., Lomakin V., Periodic micromagnetic finite element method, Journal of Magnetism and Magnetic Materials, 615, (2025); Boerner T.J., Deems S., Furlani T.R., Knuth S.L., Towns J., Access: Advancing innovation: Nsf’s advanced cyberinfrastructure coordination ecosystem: Services & support, Practice and Experience in Advanced Research Computing, ser. PEARC’23, pp. 173-176, (2023)","V. Lomakin; University of California, Department of Electrical and Computer Engineering, San Diego, 92093, United States; email: vlomakin@ucsd.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Article in press","","Scopus","2-s2.0-85216640140" +"He Z.; Liu L.","He, Zhiping (58918865000); Liu, Luqiao (35206259700)","58918865000; 35206259700","Magnetic dynamics of strained non-collinear antiferromagnet","2024","Journal of Applied Physics","135","9","093902","","","","1","10.1063/5.0192467","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85186686167&doi=10.1063%2f5.0192467&partnerID=40&md5=316550de7dde4471b72cf476ee64e777","Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, 02139, MA, United States","He Z., Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, 02139, MA, United States; Liu L., Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, 02139, MA, United States","In this work, we theoretically study the switching and oscillation dynamics in strained non-collinear antiferromagnet (AFM) Mn3X (X = Sn, Ge, etc.). Using the perturbation theory, we identify three separable dynamic modes—one uniform and two optical modes, for which we analytically derive the oscillation frequencies and effective damping. We also establish a compact, vector equation for describing the dynamics of the uniform mode, which is in analogy to the conventional Landau-Lifshitz-Gilbert (LLG) equation for ferromagnet but captures the unique features of the cluster octuple moment. Extending our model to include spatial inhomogeneity, we are able to describe the excitations of dissipative spin wave and spin superfluidity state in the non-collinear AFM. Furthermore, we carry out numerical simulations based on coupled LLG equations to verify the analytical results, where good agreements are reached. Our treatment with the perturbative approach provides a systematic tool for studying the dynamics of non-collinear AFM and is generalizable to other magnetic systems in which the Hamiltonian can be expressed in a hierarchy of energy scales. © 2024 Author(s).","","Antiferromagnetic materials; Hamiltonians; Perturbation techniques; Spin waves; Collinear antiferromagnets; Dynamic modes; Effective damping; Ferromagnets; Landau-Lifshitz-Gilbert equations; Magnetic dynamics; Optical modes; Oscillation frequency; Perturbation theory; Vector equation; Dynamics","","","","","National Science Foundation, NSF, (DMR-2104912); Semiconductor Research Corporation, SRC","Z.H. thanks Pengxiang Zhang and Chung-Tao Chou for helpful discussion. The authors acknowledge support from the National Science Foundation under Award No. DMR-2104912 and Semiconductor Research Corporation. ","Jungwirth T., Marti X., Wadley P., Wunderlich J., Antiferromagnetic spintronics, Nat. Nanotechnol., 11, 3, pp. 231-241, (2016); Baltz V., Manchon A., Tsoi M., Moriyama T., Ono T., Tserkovnyak Y., Antiferromagnetic spintronics, Rev. Mod. Phys., 90, 1, (2018); Satoh T., Cho S.-J., Iida R., Shimura T., Kuroda K., Ueda H., Ueda Y., Ivanov B.A., Nori F., Fiebig M., Spin oscillations in antiferromagnetic NiO triggered by circularly polarized light, Phys. Rev. Lett., 105, 7, (2010); Cheng R., Zhu J.-G., Xiao D., Dynamic feedback in ferromagnet-spin Hall metal heterostructures, Phys. Rev. Lett., 117, 9, (2016); Cheng R., Xiao D., Brataas A., Terahertz antiferromagnetic spin Hall nano-oscillator, Phys. Rev. Lett., 116, 20, (2016); Chen H., Niu Q., MacDonald A.H., Anomalous Hall effect arising from noncollinear antiferromagnetism, Phys. Rev. Lett., 112, 1, (2014); Nakatsuji S., Kiyohara N., Higo T., Large anomalous Hall effect in a non-collinear antiferromagnet at room temperature, Nature, 527, 7577, pp. 212-215, (2015); Kiyohara N., Tomita T., Nakatsuji S., Giant anomalous Hall effect in the chiral antiferromagnet Mn3Ge, Phys. Rev. Appl., 5, 6, (2016); Ikhlas M., Tomita T., Koretsune T., Suzuki M.-T., Nishio-Hamane D., Arita R., Otani Y., Nakatsuji S., Large anomalous Nernst effect at room temperature in a chiral antiferromagnet, Nat. Phys., 13, 11, pp. 1085-1090, (2017); Higo T., Man H., Gopman D.B., Wu L., Koretsune T., van't Erve O.M.J., Kabanov Y.P., Rees D., Li Y., Suzuki M.-T., Patankar S., Ikhlas M., Chien C.L., Arita R., Shull R.D., Orenstein J., Nakatsuji S., Large magneto-optical Kerr effect and imaging of magnetic octupole domains in an antiferromagnetic metal, Nat. Photon, 12, 2, pp. 73-78, (2018); Chen X., Higo T., Tanaka K., Nomoto T., Tsai H., Idzuchi H., Shiga M., Sakamoto S., Ando R., Kosaki H., Matsuo T., Nishio-Hamane D., Arita R., Miwa S., Nakatsuji S., Octupole-driven magnetoresistance in an antiferromagnetic tunnel junction, Nature, 613, 7944, pp. 490-495, (2023); Qin P., Yan H., Wang X., Chen H., Meng Z., Dong J., Zhu M., Cai J., Feng Z., Zhou X., Liu L., Zhang T., Zeng Z., Zhang J., Jiang C., Liu Z., Room-temperature magnetoresistance in an all-antiferromagnetic tunnel junction, Nature, 613, 7944, pp. 485-489, (2023); Tsai H., Higo T., Kondou K., Nomoto T., Sakai A., Kobayashi A., Nakano T., Yakushiji K., Arita R., Miwa S., Otani Y., Nakatsuji S., Electrical manipulation of a topological antiferromagnetic state, Nature, 580, 7805, pp. 608-613, (2020); Higo T., Kondou K., Nomoto T., Shiga M., Sakamoto S., Chen X., Nishio-Hamane D., Arita R., Otani Y., Miwa S., Nakatsuji S., Perpendicular full switching of chiral antiferromagnetic order by current, Nature, 607, 7919, pp. 474-479, (2022); Takeuchi Y., Yamane Y., Yoon J.-Y., Itoh R., Jinnai B., Kanai S., Ieda J., Fukami S., Ohno H., Chiral-spin rotation of non-collinear antiferromagnet by spin-orbit torque, Nat. Mater., 20, 10, pp. 1364-1370, (2021); Suzuki M.-T., Koretsune T., Ochi M., Arita R., Cluster multipole theory for anomalous Hall effect in antiferromagnets, Phys. Rev. B, 95, 9, (2017); Yoon J.-Y., Zhang P., Chou C.-T., Takeuchi Y., Uchimura T., Hou J.T., Han J., Kanai S., Ohno H., Fukami S., Liu L., Handedness anomaly in a non-collinear antiferromagnet under spin-orbit torque, Nat. Mater., 22, 9, pp. 1106-1113, (2023); Nomoto T., Arita R., Cluster multipole dynamics in noncollinear antiferromagnets, Phys. Rev. Res., 2, 1, (2020); Duan T.F., Ren W.J., Liu W.L., Li S.J., Liu W., Zhang Z.D., Magnetic anisotropy of single-crystalline Mn3Sn in triangular and helix-phase states, Appl. Phys. Lett., 107, 8, (2015); Tomiyoshi S., Yamaguchi Y., Magnetic structure and weak ferromagnetism of Mn 3 Sn studied by polarized neutron diffraction, J. Phys. Soc. Jpn., 51, 8, pp. 2478-2486, (1982); Liu J., Balents L., Anomalous Hall effect and topological defects in antiferromagnetic Weyl semimetals: Mn3Sn/Ge, Phys. Rev. Lett., 119, 8, (2017); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, 13, pp. 9353-9358, (1996); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1, pp. L1-L7, (1996); Miwa S., Iihama S., Nomoto T., Tomita T., Higo T., Ikhlas M., Sakamoto S., Otani Y., Mizukami S., Arita R., Nakatsuji S., Giant effective damping of octupole oscillation in an antiferromagnetic Weyl semimetal, Small Sci., 1, 5, (2021); Park P., Oh J., Uhlirova K., Jackson J., Deak A., Szunyogh L., Lee K.H., Cho H., Kim H.-L., Walker H.C., Adroja D., Sechovsky V., Park J.-G., Magnetic excitations in non-collinear antiferromagnetic Weyl semimetal Mn3Sn, Npj Quantum Mater., 3, 1, (2018); Yamane Y., Gomonay O., Sinova J., Dynamics of noncollinear antiferromagnetic textures driven by spin current injection, Phys. Rev. B, 100, 5, (2019); Dasgupta S., Tchernyshyov O., Theory of spin waves in a hexagonal antiferromagnet, Phys. Rev. B, 102, 14, (2020); Dasgupta S., Tchernyshyov O., Energy-momentum tensor of a ferromagnet, Phys. Rev. B, 98, 22, (2018); Qaiumzadeh A., Skarsvag H., Holmqvist C., Brataas A., Spin superfluidity in biaxial antiferromagnetic insulators, Phys. Rev. Lett., 118, 13, (2017); Goli V.M.L.D.P., Manchon A., Crossover from diffusive to superfluid transport in frustrated magnets, Phys. Rev. B, 103, 10, (2021); Brown P.J., Nunez V., Tasset F., Forsyth J.B., Radhakrishna P., Determination of the magnetic structure of Mn3Sn using generalized neutron polarization analysis, J. Phys.: Condens. Matter, 2, 47, (1990); Gross E.P., Structure of a quantized vortex in boson systems, Nuovo Cimento, 20, 3, pp. 454-477, (1961); Pitaevskii L.P., Vortex lines in an imperfect Bose gas, Sov. Phys. JETP, 13, 2, pp. 451-454, (1961); Sonin E.B., Spin currents and spin superfluidity, Adv. Phys., 59, 3, pp. 181-255, (2010); Chen H., MacDonald A.H.; Skarsvag H., Holmqvist C., Brataas A., Spin superfluidity and long-range transport in thin-film ferromagnets, Phys. Rev. Lett., 115, 23, (2015); Mizukami S., Wu F., Sakuma A., Walowski J., Watanabe D., Kubota T., Zhang X., Naganuma H., Oogane M., Ando Y., Miyazaki T., Long-lived ultrafast spin precession in manganese alloys films with a large perpendicular magnetic anisotropy, Phys. Rev. Lett., 106, 11, (2011)","Z. He; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, 02139, United States; email: zhiphe@mit.edu","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85186686167" +"Duan J.; Lomakin V.","Duan, Jiawei (58623889100); Lomakin, Vitaliy (35570326300)","58623889100; 35570326300","Coupled micromagnetic-electromagnetic solvers with truncated boundaries","2024","2024 IEEE INC-USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), INC-USNC-URSI 2024 - Proceedings","","","","75","","","0","10.23919/INC-USNC-URSI61303.2024.10632421","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85203197166&doi=10.23919%2fINC-USNC-URSI61303.2024.10632421&partnerID=40&md5=afbfcf9b0e2cdfb2df39a38a706b2bd4","Dept of ECE, Program in Material Science and Engineering, Center for Memory and Recording Research, University of California, San Diego, United States","Duan J., Dept of ECE, Program in Material Science and Engineering, Center for Memory and Recording Research, University of California, San Diego, United States; Lomakin V., Dept of ECE, Program in Material Science and Engineering, Center for Memory and Recording Research, University of California, San Diego, United States","Magnetization dynamics in nano- and micro-scale magnetic materials and devices is governed by the Landau–Lifshitz–Gilbert (LLG) equation. This equation links magnetization dynamics to torques arising from various physical interactions, including electromagnetic effects influenced by magnetic field time variations. At low frequencies, these effects are approximated by magnetostatics, but at higher frequencies and device sizes, electrodynamic effects, such as eddy currents, become significant. Dynamic magnetic fields are determined using dynamic Maxwell’s equations. Methods to solve Maxwell’s equations for eddy current issues include Finite Element Method (FEM) and integral equation-based techniques. Challenges in developing efficient solvers involve computational domain truncation, efficient time stepping, and coupling Maxwell’s with LLG equations. © 2024 IEEE.","","Eddy current testing; Electromagnetic field effects; Integral equations; Magnetostatics; Surface discharges; Eddy-current; Electromagnetic solvers; Electromagnetics; Landau-Lifshitz-Gilbert equations; Magnetic-field; Magnetization dynamics; Micromagnetics; Nano scale; Physical interactions; Time variations; Maxwell equations","","","","","","","","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (AP-S); Italian National Committee (ITNC) and the US National Committee (USNC) of the International Union of Radio Science (URSI); The Institute of Electrical and Electronics Engineers (IEEE)","2024 IEEE INC-USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), INC-USNC-URSI 2024","14 July 2024 through 19 July 2024","Florence","201974","","978-946396811-9","","","English","IEEE INC-USNC-URSI Radio Sci. Meet. (Jt. AP-S Symp.), INC-USNC-URSI - Proc.","Conference paper","Final","","Scopus","2-s2.0-85203197166" +"Moumni M.; Douiri S.M.; Kim J.S.","Moumni, M. (57195377066); Douiri, S.M. (57199749242); Kim, J.S. (56043084900)","57195377066; 57199749242; 56043084900","Fourier-spectral method for the Landau–Lifshitz–Gilbert equation in micromagnetism","2023","Results in Applied Mathematics","19","","100380","","","","3","10.1016/j.rinam.2023.100380","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85162123147&doi=10.1016%2fj.rinam.2023.100380&partnerID=40&md5=a87783497a4482311bf665c554ef4324","MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismaïl University of Meknes, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco; MAIS Laboratory, AMNEA Group, FST Errachidia, Moulay Ismaïl University of Meknes, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco; Department of Mathematics, Korea University, Seoul, 02841, South Korea","Moumni M., MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismaïl University of Meknes, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco; Douiri S.M., MAIS Laboratory, AMNEA Group, FST Errachidia, Moulay Ismaïl University of Meknes, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco; Kim J.S., Department of Mathematics, Korea University, Seoul, 02841, South Korea","The Landau–Lifshitz–Gilbert (LLG) equation models the temporal evolution of magnetization in continuum ferromagnets. The LLG equation has a nonconvex constraint and is highly nonlinear. In this paper, we will use the Fourier-spectral method for approximating the solution of the LLG equation with the nonconvex constraint. We consider the penalty problem and show the stability and convergence of the approximate penalty problem, and then we show the convergence of the penalty problem to a (weak) solution of the LLG equation. Computational experiments and comparison with other numerical methods are presented to demonstrate the effectiveness of the proposed method. © 2023 The Author(s)","Ferromagnetism; Fourier-spectral method; Landau–Lifshitz–Gilbert equation; Magnetization dynamics","Ferromagnetic materials; Fourier transforms; Magnetization; Nonlinear equations; Numerical methods; Equation models; Ferromagnets; Fourier; Fourier-spectral method; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Micromagnetisms; Nonconvex constraint; Spectral methods; Temporal evolution; Ferromagnetism","","","","","","","Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans Magn, 40, pp. 3443-3449, (2004); John P.B., Chebyshev and fourier spectral methods, (2001); Mercier B., An introduction to the numerical analysis of spectral methods, Lecture Notes in Physics, 318, (1989); Kreiss H., Oliger J., Methodsfor approximate solution of time dependent problems, Vol. 10, (1973); Gottlieb D., Orszag S.A., Numerical analysis of spectral methods: Theory and applications, CBMS regional conf. ser. in appl. math. Vol. 26, (1977); Majda A., McDonough J., Osher S., The Fourier methodfor non smooth initial data., Math Comp, 32, pp. 1041-1081, (1978); Costa B., Spectral methods for partial differential equations, Math J, 6, 4, pp. 1-32, (2004); Hussaini M.Y., Streett C.L., Zang T.A., Spectral methods for partial differential equations, Vol. 1, pp. 172-248, (1983); Rai N., Mondal S., Spectral methods to solve nonlinear problems: A review, J Partial Differ Equ Appl Math, 4, (2021); Shen J., Tang T., Wang L.-L., Spectral methods: Algorithms, analysis and applications, (2011); Tilioua M., Current-induced magnetization dynamics, Glob Exist Weak Solut, J Math Anal Appl, 373, 2, pp. 635-642, (2011); Brown W.F., Micromagnetics, interscience publishers, (1963); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin Dyn Syst Ser S, 1, 2, pp. 87-196, (2008); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math Models Methods Appl Sci, 16, pp. 299-316, (2006); Moumni M., Tilioua M., A finite element approximation of a current-induced magnetization dynamics model, J Math Model, 10, 1, pp. 53-69, (2022); Moumni M., Tilioua M., A finite-difference scheme for a model of magnetization dynamics with inertial effects, J Eng Math, 100, 1, pp. 95-106, (2016); Jeong D., Kim J., An accurate and robust numerical method for micromagnetics simulations, J Curr Appl Phys, 14, 3, pp. 476-483, (2014); Weinan E., Wang X.P., Numerical methods for the Landau-Lifshitz equation, SIAM J Numer Anal, pp. 1647-1665, (2001); Yang W., Wang D., Yang L.; Banas L., A numerical method for the Landau–Lifshitz equation with magnetostriction., Math Methods Appl Sci, 28, 16, pp. 1939-1954, (2005); Lions J.L., Quelques méthodes de résolution des problémes aux limites non linéaires, (1969); Zygmund A., Trigonometric series, Vol. 1, (2002)","M. Moumni; MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismaïl University of Meknes, Errachidia, P.O. Box 509, Boutalamine, 52000, Morocco; email: md.moumni@gmail.com","","Elsevier B.V.","","","","","","25900374","","","","English","Result. Appl. Math.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85162123147" +"Mudhafer A.; Najdi M.A.; Alshamkhani M.T.","Mudhafer, A. (57210213153); Najdi, M.A. (57205196138); Alshamkhani, Maher T. (57219390858)","57210213153; 57205196138; 57219390858","Emergent chiral spin textures in centrosymmetric iron garnet with spin alignment constraints","2024","Journal of Magnetism and Magnetic Materials","604","","172315","","","","0","10.1016/j.jmmm.2024.172315","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85197521210&doi=10.1016%2fj.jmmm.2024.172315&partnerID=40&md5=8b74e980cd3542c5328f3fb8a0f398ea","Chemical and Petrochemical Techniques Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq; General Directorate of Education in Basrah, Basrah, Iraq; Fuel and Energy Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq","Mudhafer A., Chemical and Petrochemical Techniques Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq; Najdi M.A., General Directorate of Education in Basrah, Basrah, Iraq; Alshamkhani M.T., Fuel and Energy Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq","Chiral spin textures have emerged as a captivating class of topological matter. These intriguing structures harbor localized and topologically protected magnetic textures, rendering them promising candidates for novel spintronic applications. Here, the emergent chiral spin textures in an iron garnet with nanodisk configuration have been micromagnatically simulated based on the Landau-Lifshitz-Gilbert equation (LLG) of COMSOL Multiphysics. The modification of magnetic spin texture in the considered iron garnet has been controlled by introducing the interfacial Dzyaloshinskii-Moriya interaction (I-DMI) and spin alignment constraints as locally pinned spins and curvilinear defects at edges. These boundary conditions induced interesting chiral textures not commonly observed in such iron garnet due to its centrosymmetric crystal structure. The simulation results showed the presence of two distinct regions of spin texture: inside and outside the pinning boundary. By systematically varying the DMI strength (D) with the size of the pinning boundary (Rpin) and the number of defects (Ndef), the emerging chiral spin textures have been explored and reported, including the existence of ramified helical stripes, skyrmions, and skyrmions-like textures such as elongated skyrmions, chiral horseshoe domains, biskyrmions and target skyrmions (TSk) (2π-TSk and 3π-TSk). Also, it has been reported that various collapses occur in the final spin texture states, leading to the transition from one state to another when varying the values of Rpin and Ndef with D. © 2024 Elsevier B.V.","Chiral magnet; Ferromagnetic insulators; Interfacial DMI; Spin pinning; Spin texture; YIG","Crystal structure; Iron; Multiphysics; Textures; Topology; Yttrium iron garnet; Centrosymmetric; Chiral magnets; Ferromagnetic insulator; Interfacial DMI; Iron garnet; Localised; Skyrmions; Spin alignment; Spin pinning; Spin textures; Defects","","","","","","","Fakhrul T., Et al., Influence of substrate on interfacial Dzyaloshinskii-Moriya interaction in epitaxial Tm3Fe5O12 films, Phys. Rev. B, 107, 5, (2023); Xia S.Y., Et al., Source and origin of the interfacial Dzyaloshinskii-Moriya interaction in a heavy-metal| magnetic-insulator bilayer, Phys. Rev. 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Magn., 59, 2, pp. 1-6, (2022); Sheng L., Et al., Magnonics based on thin-film iron garnets, J. Phys. Soc. Jpn., 90, 8, (2021); Jiang Z., Et al., Integrating Magnons for Quantum Information, Appl. Phys. Lett., 123, (2023); Reza A.K., Roy K., Effect of Dzyaloshinskii-Moriya interaction at ferrimagnet and heavy metal interface, IEEE Trans. Electron Devices, 66, 3, pp. 1599-1604, (2019); Ulrichs H., From chaotic spin dynamics to noncollinear spin textures in YIG nanofilms by spin-current injection, Phys. Rev. B, 102, 17, (2020); Gorobets O.Y., Et al., (2021); Wang H., Et al., Chiral spin-wave velocities induced by all-garnet interfacial Dzyaloshinskii-Moriya interaction in ultrathin yttrium iron garnet films, Phys. Rev. Lett., 124, 2, (2020); Gorbatov O.I., Et al., Magnetic exchange interactions in yttrium iron garnet: A fully relativistic first-principles investigation, Phys. Rev. B, 104, 17, (2021); Trossman J., Et al., Nonreciprocal spin-wave propagation in YIG/GGG: a limit on the DMI parameter, J. Korean Phys. Soc., pp. 1-5, (2023); Song C., Zhao L., Liu J., Jiang W., Experimental realization of a skyrmion circulator, Nano Lett., 22, 23, pp. 9638-9644, (2022); Deng P., Zhuo F., Li H., Cheng Z., Mirroring Skyrmions in synthetic antiferromagnets via modular design, Nanomaterials, 13, 5, (2023); Chen R., Gao Y., Zhang X., Zhang R., Yin S., Chen X., Song C., Realization of isolated and high-density skyrmions at room temperature in uncompensated synthetic antiferromagnets, Nano Lett., 20, 5, pp. 3299-3305, (2020); Brown W.F., Micromagnetics, (1963); Landau L.D., Lifshits E.M., Phys. Zs. Sowjet., 8, (1935); Comstock R.L., Magnetoelastic coupling constants of the ferrites and garnets, Proc. IEEE, 53, 10, pp. 1508-1517, (1965); Lucassen J., Meijer M.J., Kurnosikov O., Swagten H.J., Koopmans B., Lavrijsen R., Duine R.A., Tuning magnetic chirality by dipolar interactions, Phys. Rev. Lett., 123, 15, (2019); Hrabec, Sampaio J., Belmeguenai M., Gross I., Weil R., Cherif S.M., Stashkevich A., Jacques V., Thiaville A., Rohart S., Nat. Comm., 8, (2017); Moreau-Luchaire C., Moutafis N., Reyren J., Sampaio C.A.F., Vaz N.V., Horne K., Bouzehouane K., Garcia C., Deranlot P., Warnicke P., Wohlhuter P., George J.-M., Weigand M., Raabe J., Cros V., Fert A., Nat. Nanotechnol., 11, (2016); Yu W., Xiao J., Bauer G.E., Hopfield neural network in magnetic textures with intrinsic Hebbian learning, Phys. Rev. B, 104, 18, (2021); Polyakov M., Ter-Martirosian K., Metastable states of two-dimensional isotropic ferromagnets, ETP Lett., 22, pp. 245-248, (1975); Mermin N.D., The topological theory of defects in ordered media, Rev. Mod. 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X, 5, 4, (2015); Hagemeister J., Et al., Controlled creation and stability of k π skyrmions on a discrete lattice, Phys. Rev. B, 97, 17, (2018)","A. Mudhafer; Chemical and Petrochemical Techniques Engineering Department, Basra Engineering Technical College, Southern Technical University, Basra, Iraq; email: a.mudhafer@stu.edu.iq","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85197521210" +"Zhong P.; Chen X.; Tang S.; Tătaru D.","Zhong, Penghong (25643497200); Chen, Xingfa (57219648037); Tang, Shengxiang (57216781851); Tătaru, Daniel (6603877307)","25643497200; 57219648037; 57216781851; 6603877307","GLOBAL WELL-POSEDNESS OF THE RADIAL SYMMETRY LANDAU-LIFSHITZ-GILBERT EQUATION IN DIMENSIONS 2","2023","Mathematical Reports","25(75)","4","","513","526","13","0","10.59277/mrar.2023.25.75.4.513","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183959800&doi=10.59277%2fmrar.2023.25.75.4.513&partnerID=40&md5=160b21ef262beb1fcffe8726ac4da69b","Guangdong University of Education School of Mathematics, Guangzhou, 510303, China","Zhong P., Guangdong University of Education School of Mathematics, Guangzhou, 510303, China; Chen X., Guangdong University of Education School of Mathematics, Guangzhou, 510303, China; Tang S., Guangdong University of Education School of Mathematics, Guangzhou, 510303, China; Tătaru D., Guangdong University of Education School of Mathematics, Guangzhou, 510303, China","The global solution of the 2-dimensional Landau-Lifshitz-Gilbert (LLG) equation on the sphere S2 is studied. By the Hasimoto transformation, an equivalent complex-valued equation is deduced under cylindrical symmetric coordinates. Then the global H2 well-posedness of the Cauchy problem for this complex system with minimal regularity assumptions on the initial data is proved, and the well-posedness of the LLG equation is presented. © 2023 Editura Academiei Romane. All rights reserved.","Hasimoto transformation; Landau-Lifshitz-Gilbert equation; well-posedness","","","","","","Fund for Science and Technology of Guangzhou, (202102080428); Special Projects in Key Areas of Guangdong Province, (ZDZX1088)","The authors’ work on this material was supported by Special Projects in Key Areas of Guangdong Province (No. ZDZX1088), and, in part, by the Fund for Science and Technology of Guangzhou (No. 202102080428). MATH. REPORTS 25(75) (2023), 4, 513–526 doi: 10.59277/mrar.2023.25.75.4.513","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and nonuniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Bejenaru I., Ionescu A.D., Kenig C.E., Global existence and uniqueness of Schrödinger maps in dimensions d ≥ 4, Adv. Math, 215, pp. 263-291, (2007); Bejenaru I., Ionescu A.D., Kenig C.E., Tataru D., Global Schrödinger maps in dimensions d ≥ 2: small data in the critical Sobolev spaces, Ann. of Math, 173, pp. 1443-1506, (2011); Chang N., Shatah J., Uhlenbeck K., Schrödinger maps, Comm. Pure Appl. Math, 53, 5, pp. 590-602, (2000); Ding W., Wang Y., Local Schrödinger flow into Kähler manifolds, Sci. China, 44, pp. 1446-1464, (2001); Guo B., Hong M., The Landau-Lifshitz equation of the ferromagnetic spin chain and harmonic maps, Calc. Var. Partial Differential Equations, 1, pp. 311-334, (1993); Guo B., Huang H., Smooth solution of the generalized system of ferro-magnetic chain, Discrete Contin. Dyn. Syst, 5, pp. 729-740, (1999); Gustafson S., Kang K., Tsai T., Schrödinger flow near harmonic maps, Comm. Pure Appl. Math, 60, pp. 463-499, (2007); Harpes P., Uniqueness and bubbling of the 2-dimensional Landau-Lifshitz flow, Calc. Var. Partial Differential Equations, 20, pp. 213-229, (2004); Harpes P., Bubbling of approximations for the 2-D Landau-Lifshitz flow, Comm. Partial Differential Equations, 31, pp. 1-20, (2006); Hube A., Periodic solutions for the Landau-Lifshitz-Gilbert equation, J. Differential Equations, 250, pp. 2462-2484, (2011); Ionescu A.D., Kenig C.E., Low-regularity Schrödinger maps, II: global well-posedness in dimensions d ≥ 3, Comm. Math. Phys, 271, pp. 523-559, (2007); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Z. Sowjetunion, 8, pp. 101-114, (1935); Melcher C., Existence of partially regular solutions for Landau-Lifshitz equations in R3, Comm. Partial Differential Equations, 30, pp. 567-587, (2005); McGahagan H., An approximation scheme for Schrödinger maps, Comm. Partial Differential Equations, 32, pp. 375-400, (2007); Melcher C., Global solvability of the Cauchy problem for the Landau-Lifshitz-Gilbert equation in higher dimensions, Indiana Univ. Math. J, 61, pp. 1175-1200, (2012); Merle F., Raphael P., Radnianski I., Blowup dynamics for smooth data equivariant solutions to the critical Schrödinger map problem, Invent. Math, 193, pp. 249-365, (2013); Perelman G., Blow up dynamics for equivariant critical Schrödinger maps, Comm. Math. Phys, 330, pp. 69-105, (2014); Sulem P.L., Sulem C., Bardos C., On the continuous limit for a system of classical spins, Comm. Math. Phys, 107, pp. 431-454, (1986)","","","Publishing House of the Romanian Academy","","","","","","15823067","","","","English","Math. Rep.","Article","Final","","Scopus","2-s2.0-85183959800" +"Demin G.D.; Lobanov B.V.; Dyuzhev N.A.","Demin, Gleb D. (55532223900); Lobanov, Bogdan V. (59296844300); Dyuzhev, Nikolay A. (7801566332)","55532223900; 59296844300; 7801566332","Frequency Analysis of the GMI Effect in a Thin-Film Magnetic Structure With an Insulator in the Linear and Nonlinear Operating Regimes","2024","International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices, EDM","","","","170","173","3","0","10.1109/EDM61683.2024.10615123","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85201937693&doi=10.1109%2fEDM61683.2024.10615123&partnerID=40&md5=be7c550de4f29aa2222e1820bf5b019d","R&D Center «MEMSEC», National Research University of Electronic Technology (MIET), Zelenograd, Moscow, Russian Federation","Demin G.D., R&D Center «MEMSEC», National Research University of Electronic Technology (MIET), Zelenograd, Moscow, Russian Federation; Lobanov B.V., R&D Center «MEMSEC», National Research University of Electronic Technology (MIET), Zelenograd, Moscow, Russian Federation; Dyuzhev N.A., R&D Center «MEMSEC», National Research University of Electronic Technology (MIET), Zelenograd, Moscow, Russian Federation","In this work, we propose a micromagnetic approach to model the CoFeSiB-SiO2-Al-SiO2-CoFeSiB structure, which exhibits the giant magnetoimpedance effect. It was found that in the nonlinear mode of detecting an external magnetic field of about 1 Oe (at a current I = 37 mA), directed along the magnetic anisotropy axis of the CoFeSiB film, the signal increases almost 3 times when the frequency changes from 10 to 40 MHz (from about 90.9 to 268.9 mV). At the same time, the variation of the current amplitude from 12.3 to 37 mA at a frequency of 20 MHz leads to an increase in the signal amplitude by several orders of magnitude (from 3.8 to 146 mV). In this case, the resonant response (~146 mV) at a relatively low magnetic field (H≈1 Oe) is observed due to the predominance of higher harmonics, while in the linear mode (I<37 mA) this field becomes insufficient to achieve the maximum output signal. The results obtained can be used to develop a promising type of giant magnetoimpedance sensors based on thin-film magnetic structure with an insulating layer separating the current-carrying conductor from the ferromagnetic layer to reduce the eddy current loss at high frequencies. © 2024 IEEE.","coil voltage; excitation frequency; giant magnetoimpedance effect; Landau-Lifshitz-Gilbert (LLG) equation; micromagnetic simulation; spin dynamics; thin-film magnetic structure","Aluminum compounds; Cobalt alloys; Crystal lattices; Magnetic thin films; Organoclay; Silica; Surface discharges; Thin film transistors; CoFeSiB; Coil voltage; Excitation frequency; Frequency Analysis; Giant magneto impedance effect; GMI effects; Landau-Lifshitz-Gilbert equations; Micromagnetic simulations; Thin films-magnetic; Thin-film magnetic structure; Magnetic anisotropy","","","","","Ministry of Education and Science of the Russian Federation, Minobrnauka, (FSMR-2024- 0004); Ministry of Education and Science of the Russian Federation, Minobrnauka","The work was performed using the equipment of R&D Center \u00ABMEMSEC\u00BB and supported by the Ministry of Science and Higher Education of the Russian Federation (State assignment No. FSMR-2024- 0004).","Mardani R., Fabrication of FM/NM/FM hetero-structure multilayers and investigation on structural and magnetic properties: application in GMI magnetic sensors, J. Supercond. Nov. Magn., 33, 2, pp. 503-509, (2020); Melnikov G.Yu., Lepalovskij V.N., Svalov A.V., Safronov A.P., Kurlyandskaya G.V., Magnetoimpedance thin film sensor for detecting of stray fields of magnetic particles in blood vessel, Sensors, 21, 11, (2021); Morikawa T., Nishibe Y., Yamadera H., Nomomura Y., Takeuchi M., Sakata J., Taga Y., Enhancement of giant magneto-impedance in layered film by insulator separation, IEEE Trans. Magn., 32, 5, pp. 4965-4967, (1996); Jimenez V.O., Et al., Magnetoimpedance biosensors and real-time healthcare monitors: progress, opportunities, and challenges, Biosensors, 12, 7, (2022); Kraus L., GMI modeling and material optimization, Sensors and Actuators A: Physical, 106, 1-3, pp. 187-194, (2003); Buznikov N.A., Yoon S.-S., Kim C.-O., Kim C., Influence of current amplitude on asymmetric off-diagonal magnetoimpedance in field-annealed amorphous ribbons, IEEE Trans. Magn., 41, 10, pp. 3646-3648, (2005); Chai X.L., Zeng D.C., Liu G.X., Yu H.Y., Zhong X.C., Liu Z.W., Influence of current amplitude on the nonlinear asymmetric ac volt–ampere characteristics in amorphous ribbons with GMI effect, Journal of Magnetism and Magnetic Materials, 321, 9, pp. 1272-1275, (2009); Kraus L., Nonlinear Magnetoimpedance in Field- and Stress-Annealed Amorphous Ribbons, IEEE Trans. Magn., 46, 2, pp. 428-431, (2010); COMSOL Multiphysics® v. 6.2, (2021); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., The design and verification of MuMax3, AIP Advances, 4, 10, (2014); Hwang J.Y., Yim H.I., Kim M.Y., Rhee J.R., Chun B.S., Kim Y.K., Kim T., Magnetoresistance and magnetization switching characteristics of magnetic tunnel junctions with amorphous CoFeSiB single and synthetic antiferromagnet free layers, J. Appl. Phys., 99, 8, (2006)","G.D. Demin; R&D Center «MEMSEC», National Research University of Electronic Technology (MIET), Moscow, Zelenograd, Russian Federation; email: gddemin@gmail.com","","IEEE Computer Society","","25th IEEE International Conference of Young Professionals in Electron Devices and Materials, EDM 2024","28 June 2024 through 2 July 2024","Altai","201835","23254173","979-835038923-4","","","English","Int. Conf. Young Spl. Micro/Nanotechnol. Electron Devices, EDM","Conference paper","Final","","Scopus","2-s2.0-85201937693" +"Jiang N.; Liu H.; Luo Y.-L.","Jiang, Ning (57203201441); Liu, Hui (48361261500); Luo, Yi-Long (57202074622)","57203201441; 48361261500; 57202074622","On well-posedness of an evolutionary model for magnetoelasticity: hydrodynamics of viscoelasticity and Landau-Lifshitz-Gilbert systems","2023","Journal of Differential Equations","367","","","79","123","44","2","10.1016/j.jde.2023.04.040","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85158047183&doi=10.1016%2fj.jde.2023.04.040&partnerID=40&md5=4dd1b32b4aac4762540630c3f9f11447","School of Mathematics and Statistics, Wuhan University, Wuhan, 430072, China; School of Mathematics, South China University of Technology, Guangzhou, 510641, China","Jiang N., School of Mathematics and Statistics, Wuhan University, Wuhan, 430072, China; Liu H., School of Mathematics and Statistics, Wuhan University, Wuhan, 430072, China; Luo Y.-L., School of Mathematics, South China University of Technology, Guangzhou, 510641, China","In this paper, we first prove the local-in-time existence of the evolutionary model for magnetoelasticity with finite initial energy by employing the nonlinear iterative approach to deal with the constraint on values of the magnetization |M(t,x)|=1 in the Landau-Lifshitz-Gilbert (LLG) equation. We reformulate the evolutionary model near the constant equilibrium for magnetoelasticity with vanishing external magnetic field, so that a further dissipative term will be sought from the elastic stress. We thereby justify the global well-posedness to the evolutionary model for magnetoelasticity with zero external magnetic field under small size of initial data. © 2023 Elsevier Inc.","Deformation gradient flow; Global classical solutions; Landau-Lifshitz-Gilbert equation; Magnetoelasticity","","","","","","National Natural Science Foundation of China, NSFC, (11471181, 11731008, 12201220, 12221001); National Natural Science Foundation of China, NSFC; Guangzhou Science and Technology Program key projects, (202201010497); Guangzhou Science and Technology Program key projects; Basic and Applied Basic Research Foundation of Guangdong Province, (2021A1515110210); Basic and Applied Basic Research Foundation of Guangdong Province","We are very grateful to the anonymous referees for their suggestions and comments for improving our paper. The first author N. J. was supported by grants from the National Natural Science Foundation of China under contract No. 11471181 , No. 11731008 and No. 12221001 . The last author Y.-L. L. was supported by grants from the National Natural Science Foundation of China under contract No. 12201220 , the Guangdong Basic and Applied Basic Research Foundation under contract No. 2021A1515110210 , and the Science and Technology Program of Guangzhou, China under the contract No. 202201010497 .","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and nonuniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Benesova B., Forster J., Liu C., Schlomerkemper A., Existence of weak solutions to an evolutionary model for magnetoelasticity, SIAM J. Math. Anal., 50, 1, pp. 1200-1236, (2018); Brown W.F., Magnetoelastic Interactions, (1966); Carbou G., Efendiev M.A., Fabrie P., Global weak solutions for the Landau-Lifschitz equation with magnetostriction, Math. Methods Appl. Sci., 34, pp. 1274-1288, (2011); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in a bounded domain, Differ. Integral Equ., 14, pp. 213-229, (2001); Chipot M., Shafrir I.I., Valente V., Caffarelli G.V., On a hyperbolic-parabolic system arising in magnetoelasticity, J. Math. Anal. Appl., 352, pp. 120-131, (2009); DeSimone A., Dolzmann G., Existence of minimizers for a variational problem in two-dimensional nonlinear magnetoelasticity, Arch. Ration. Mech. Anal., 144, 2, pp. 107-120, (1998); DeSimone A., James R.D., A constrained theory of magnetoelasticity, J. Mech. Phys. Solids, 50, 2, pp. 283-320, (2002); DeSimone A., Podio-Guidugli P., Inertial and self-interactions in structured continua: liquid crystals and magnetostrictive solids, Microstructure and Phase Transitions in Solids, Meccanica, 30, 5, pp. 629-640, (1995); DeSimone A., Podio-Guidugli P., On the continuum theory of deformable ferromagnetic solids, Arch. Ration. Mech. Anal., 136, 3, pp. 201-233, (1996); Forster J., Variational Approach to the Modeling and Analysis of Magnetic Complex Fluids, (2016); Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev., 100, (1955); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); James R.D., Kinderlehrer D., Theory of magnetostriction with applications to TbxDy1−xFe2, Philos. Mag., 68, pp. 237-274, (1993); Jiang N., Luo Y.-L., On well-posedness of Ericksen-Leslie's hyperbolic incompressible liquid crystal model, SIAM J. Math. Anal., 51, 1, pp. 403-434, (2019); Kalousek M., Kortum J., Schlomerkemper A., Mathematical analysis of weak and strong solutions to an evolutionary model for magnetoviscoelasticity, Discrete Contin. Dyn. Syst., Ser. S, 14, 1, pp. 17-39, (2021); Kruzik M., Stefanelli U., Zeman J., Existence results for incompressible magnetoelasticity, Discrete Contin. Dyn. Syst., 35, pp. 2615-2623, (2015); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Lin F.-H., Liu C., Nonparabolic dissipative systems modeling the flow of liquid crystals, Commun. Pure Appl. Math., 48, 5, pp. 501-537, (1995); Lin F.-H., Liu C., Zhang P., On hydrodynamics of viscoelastic fluids, Commun. Pure Appl. Math., 58, 11, pp. 1437-1471, (2005); Lin F.-H., Zhang P., On the initial-boundary value problem of the incompressible viscoelastic fluid system, Commun. Pure Appl. Math., 61, 4, pp. 539-558, (2008); Liu C., Walkington N.J., An Eulerian description of fluids containing viscoelastic particles, Arch. Ration. Mech. Anal., 159, pp. 229-252, (2001); Maugin G.A., A continuum theory of deformable ferrimagnetic bodies. I. Field equations, J. Math. Phys., 117, pp. 1727-1738, (1976); Melcher C., A dual approach to regularity in thin film micromagnetics, Calc. Var. Partial Differ. Equ., 29, pp. 85-98, (2007); Melcher C., Thin-film limits for Landau-Lifshitz-Gilbert equations, SIAM J. Math. Anal., 42, pp. 519-537, (2010); Mielke A., Roubicek T., Rate-Independent Systems: Theory and Application, Appl. Math. Sci., (2015); Nochetto R., Salgado A., Tomas I., The equations of ferrohydrodynamics: modeling and numerical methods, Math. Models Methods Appl. Sci., 26, 13, pp. 2393-2449, (2016); Rosensweig R.E., Magnetic fluids, Annu. Rev. Fluid Mech., 19, pp. 437-463, (1987); Roubicek T., Tomassetti G., A thermodynamically consistent model of magneto-elastic materials under diffusion at large strains and its analysis, Z. Angew. Math. Phys., 69, 3, (2018); Temam R., Navier-Stokes Equations. Theory and Numerical Analysis, Studies in Mathematics and Its Applications, 2, (1977); Tiersten H.F., Coupled magnetomechanical equations for magnetically saturated insulators, J. Math. Phys., 5, pp. 1298-1318, (1964); Tiersten H.F., Variational principle for saturated magnetoelastic insulators, J. Math. Phys., 6, pp. 779-787, (1965); Zhao W., Local well-posedness and blow-up criteria of magneto-viscoelastic flows, Discrete Contin. Dyn. Syst., 38, 9, pp. 4637-4655, (2018); Roubicek T., Landau theory for ferro-paramagnetic phase transition in finitely-strained viscoelastic magnets, (2023)","H. Liu; School of Mathematics and Statistics, Wuhan University, Wuhan, 430072, China; email: hui.liu@whu.edu.cn","","Academic Press Inc.","","","","","","00220396","","JDEQA","","English","J. Differ. Equ.","Article","Final","","Scopus","2-s2.0-85158047183" +"Duan J.; Wang X.; Lomakin V.","Duan, Jiawei (58623889100); Wang, Xueyang (57204834216); Lomakin, Vitaliy (35570326300)","58623889100; 57204834216; 35570326300","Hybrid Superposition Integral - Poisson Solver Method for the Magnetostatic Field in Finite Element Micromagnetic Solvers","2023","IEEE Transactions on Magnetics","59","11","7002205","","","","2","10.1109/TMAG.2023.3297951","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85176010269&doi=10.1109%2fTMAG.2023.3297951&partnerID=40&md5=a5328f6f1da564778ec80adccb7fc3a5","University of California, Center for Memory and Recording Research, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States","Duan J., University of California, Center for Memory and Recording Research, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States; Wang X., University of California, Center for Memory and Recording Research, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States; Lomakin V., University of California, Center for Memory and Recording Research, Department of Electrical and Computer Engineering, San Diego, 92093, CA, United States","A hybrid integral evaluation - differential equation approach is introduced for the computation of the magnetostatic fields in finite-element method (FEM)-based micromagnetic solvers. The approach calculates the magnetostatic field at the boundary of the computational domain or any additional surfaces by direct superposition via a fast approach, such as the adaptive integral method based on the fast Fourier transform (FFT), and uses this surface values to formulate a Poisson equation problem with Dirichlet boundary conditions to compute the field in the bulk of the structure. The benefits of this hybrid approach include a significant reduction of the sparse matrices used in the accurate integral evaluation with the associated memory reduction as well as a rapidly convergent Poisson solver without a need of significantly extending the domain size. Additional benefits include the ability to subdivide the problem into a set of smaller problems with multiple Poisson problems for parallelization. © 1965-2012 IEEE.","Integral evaluation; Landau-Lifshitz-Gilbert (LLG) equation; magnetostatic field; micromagnetics; Poisson equation","Boundary conditions; Finite element method; Integral equations; Magnetostatics; Poisson equation; Adaptive integral method; Computational domains; Dirichlet boundary condition; Integral evaluation; Landau-Lifshitz-Gilbert equations; Magnetostatic field; Micromagnetics; Poisson solvers; Superposition integral; Surface values; Fast Fourier transforms","","","","","","","Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev, 100, (1955); Kunz K.S., Luebbers R.J., The Finite Difference Time Domain Method for Electromagnetics, (1993); Yee K., Numerical solution of initial boundary value problems involving Maxwell's equations in isotropic media, IEEE Trans. Antennas Propag, AP-14, 3, pp. 302-307, (1966); Arlett P.L., Bahrani A.K., Zienkiewicz O.C., Application of finite elements to the solution of Helmholtz's equation, Proc. Inst. Elect. Eng, 115, 12, pp. 1762-1766, (1968); Jin J.-M., The Finite Element Method in Electromagnetics, (2002); Mansuripur M., Giles R., Demagnetizing field computation for dynamic simulation of the magnetization reversal process, IEEE Trans. Magn, MAG-24, 6, pp. 2326-2328, (1988); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: Fast micromagnetic simulator for complex magnetic structures, J. Appl. Phys, 109, 7, (2011); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetizing fields, IEEE Trans. Magn, 26, 2, pp. 415-417, (1990); Phillips J.R., White J.K., A precorrected-FFT method for electrostatic analysis of complicated 3-D structures, IEEE Trans. Comput.-Aided Design Integr. Circuits Syst, 16, 10, pp. 1059-1072, (1997); Bleszynski E., Bleszynski M., Jaroszewicz T., AIM: Adaptive integral method for solving large-scale electromagnetic scattering and radiation problems, Radio Sci, 31, 5, pp. 1225-1251, (1996); Li S., Chang R., Boag A., Lomakin V., Fast electromagnetic integral-equation solvers on graphics processing units, IEEE Antennas Propag. Mag, 54, 5, pp. 71-87, (2012); Wilton D., Rao S., Glisson A., Schaubert D., Al-Bundak O., Butler C., Potential integrals for uniform and linear source distributions on polygonal and polyhedral domains, IEEE Trans. Antennas Propag, AP-32, 3, pp. 276-281, (1984); Greengard L., Rokhlin V., A fast algorithm for particle simulations, J. Comput. Phys, 73, 2, pp. 325-348, (1987); Li S., Livshitz B., Lomakin V., Fast evaluation of Helmholtz potential on graphics processing units (GPUs), J. Comput. Phys, 229, 22, pp. 8463-8483, (2010)","J. Duan; University of California, Center for Memory and Recording Research, Department of Electrical and Computer Engineering, San Diego, 92093, United States; email: jduan@ucsd.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85176010269" +"Honda S.; Sonobe Y.","Honda, Syuta (20734109200); Sonobe, Yoshiaki (7004136579)","20734109200; 7004136579","Magnetization reversal via domain wall motion in vertical high-aspect-ratio nanopillar with two magnetic junctions","2024","Journal of Physics D: Applied Physics","57","17","175002","","","","1","10.1088/1361-6463/ad2120","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183963198&doi=10.1088%2f1361-6463%2fad2120&partnerID=40&md5=d47853cbba1e253a56b094965bbfd494","Department of Pure and Applied Physics, Kansai University, 3-3-35 Yamate-cho, Suita, 564-8680, Japan; Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, 560-8531, Japan; Research Organization for Nano & Life Innovation, Waseda University, 513 Waseda-Tsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041, Japan; Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan","Honda S., Department of Pure and Applied Physics, Kansai University, 3-3-35 Yamate-cho, Suita, 564-8680, Japan, Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, 560-8531, Japan; Sonobe Y., Research Organization for Nano & Life Innovation, Waseda University, 513 Waseda-Tsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041, Japan, Institute of Materials and Systems for Sustainability, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan","A vertical ferromagnetic (FM) nanopillar can be used as magnetic memory owing to characteristics such as its high storage capacity and high thermal stability. The perpendicular shape anisotropy (PSA) of the pillar enables its magnetization direction to be stabilized. A pillar with a high aspect ratio exhibits both strong PSA and magnetization with high thermal stability. Reversing the magnetization direction of such a pillar using the current flowing through it is a significant challenge in spintronics. However, spin injection from another FM layer alone cannot reverse the magnetization of pillars of which the length exceeds 100 nm. This motivated us to propose a magnetic junction (MJ) consisting of a high-aspect-ratio FM nanopillar with two thin FM layers. Using micromagnetic simulation, we demonstrate the magnetization reversal of a 150 nm-long pillar with a diameter of 15 nm. The simulation revealed that the magnetization of the pillar reverses because of the spin transfer torque induced by the spin injection from the two thin FM layers and the spin-polarized current (SPC) flowing in the pillar in the longitudinal direction. During the magnetization reversal process, a domain wall (DW) first forms at one end of the pillar due to the spin injection. Then, driven by the SPC, the DW moves to the other end of the pillar, and the magnetization is reversed. The magnetization direction of the pillar, controlled by changing the direction of the current flowing through the pillar, can be evaluated from the respective magnetoresistance values of the two MJs. Alternatively, by pinning the DW in the pillar, a three-value magnetic memory can be developed. In addition, multi-bit and analog memories can be developed by controlling the pinning position of the DW. The high-aspect-ratio pillar-writing scheme is foreseen to pave the way for the practical development of next-generation spintronic devices. © 2024 IOP Publishing Ltd.","domain wall motion; LLG equation; multi-value memory; PSA-MRAM","Aspect ratio; Equations of motion; Frequency modulation; Magnetic recording; Magnetization reversal; MRAM devices; Thermodynamic stability; Current flowing; Domain wall motion; High aspect ratio; LLG equation; Magnetization direction; Multi-value; Multi-value memory; NanoPillar; Perpendicular shape anisotropy-MRAM; Shape anisotropy; Domain walls","","","","","Japan Society for the Promotion of Science, JSPS, (20H02607, 23K17765); Japan Science and Technology Agency, JST, (JPMJCR21C1); Core Research for Evolutional Science and Technology, CREST","This study was supported by CREST, Japan Science and Technology Agency (Grant No. JPMJCR21C1) and the Japan Society for the Promotion of Science KAKENHI (Grant Nos. 20H02607 and 23K17765).","Watanabe K, Jinnai B, Fukami S, Sato H, Ohno H, Nat. Commun, 9, (2018); Jinnai B, Igarashi J, Watanabe K, Funatsu T, Sato H, Fukami S, Ohno H, IEEE Int. Electron Devices Meeting (IEDM) 2020 San Francisco, (2020); Lu Y, Altman R A, Marley A, Rishton S A, Trouilloud P L, Xiao G, Gallagher W J, Parkin S S P, Appl. Phys. Lett, 70, (1997); Perrissin N, Lequeux S, Strelkov N, Chavent A, Vila L, Buda-Prejbeanu L D, Auffret S, Sousa R C, Prejbeanu I L, Dieny B, Nanoscale, 10, (2018); Jinnai B, Igarashi J, Watanabe K, Enobio E C I, Fukami S, Ohino H, Appl. Phys. Lett, 118, (2021); Wisniowski P, Almeida J M, Cardoso S, Barradas N P, Freitas P P, J. Appl. Phys, 103, (2008); Perrissin N, Et al., J. Phys. D: Appl. Phys, 52, (2019); Perrissin N, Et al., J. Phys. D: Appl. Phys, 52, (2019); Lequeux S, Et al., Nanoscale, 12, (2020); Igarashi J, Jinnai B, Desbuis V, Mangin S, Fukami S, Ohno H, Appl. Phys. Lett, 118, (2021); Zhang W, Tong Z, Xiong Y, Wang W, Shao Q, J. Appl. Phys, 129, (2021); Bhat S S, Enamullah Lee S-C, Bhattacharjee S, J. Phys.: Condens. Matter, 32, (2020); Hnida K E, Zywczak A, Gajewska M, Marciszko M, Sulka G D, Przybylski M, Electrochim. Acta, 205, (2016); Zhang L, Lu X, Wang J, Ni L, Yan Y, Meng H, Liu B, Wu J, Xu Y, IEEE Magn. Lett, 12, (2021); Rial J, Proenca M P, Nanomaterials, 10, (2020); Hung Y M, Li T, Hisatomi R, Shiota Y, Moriyama T, Ono T, J. Magn. Soc. Japan, 45, (2021); Kang W, Zhao W, Wang Z, Zhang Y, Klein J-O, Chappert C, Zhang Y, Ravelosona D, IEEE Trans. Magn, 50, (2014); Koch R H, Katine J A, Sun J Z, Phys. Rev. Lett, 92, (2004); Kubota H, Fukushima A, Ootani Y, Yuasa S, Ando K, Maehara H, Tsunekawa K, Djayaprawira D D, Watanabe N, Suzuki Y, Jpn. J. Appl. Phys, 44, (2005); Slonczewski J C, J. Magn. Magn. Mater, 159, (1996); Berger L, Phys. Rev. B, 54, (1996); Wang K L, Alzate J G, Amiri P K, J. Phys. D: Appl. Phys, 46, (2013); Mihajlovic G, Smith N, Santos T, Li J, Terris B D, Katine J A, Appl. Phys. Lett, 117, (2020); Li S, Lv C, Lin X, Wei G, Xiong Y, Yang W, Wang Z, Zhang Y, Zhao W, Appl. Phys. Lett, 119, (2021); Kang K, Lee W-B, Lee D-K, Lee K-J, Choi G-M, Appl. Phys. Lett, 118, (2021); Kimura T, Hamrle J, Otani Y, Phys. Rev. B, 72, (2005); Yamaki Y, Honda S, Itoh H, Sci. Tech. Rep. Kansai Univ, 64, (2022); Honda S, Itoh H, J. Nanosci. Nanotechnol, 12, (2012); Cacoilo N, Lequeux S, Teixeira B M S, Dieny B, Sousa R C, Sobolev N A, Fruchart O, Prejbeanu I L, Buda-Prejbeanu L D, Phys. Rev. Appl, 16, (2021); Honda S, Sonobe Y, J. Phys. D: Appl. Phys, 55, (2022); Honda S, Sonobe Y, Intermag 2023, (2023); Nakatani Y, Uesaka Y, Hayashi N, Jpn. J. Appl. Phys, 28, (1989); Zhang S, Li Z, Phys. Rev. Lett, 93, (2004); Thiaville A, Nakatani Y, Miltat J, Suzuki Y, Europhys. Lett, 69, (2005); Barnes S E, Maekawa S, Phys. Rev. Lett, 95, (2005); Niu D X, Zou X, Wu J, Xu Y B, Appl. Phys. Lett, 94, (2009); Dubois S, Piraux L, George J M, Ounadjela K, Duvail J L, Fert A, Phys. Rev. B, 60, (1999); Bhattacharjee S, Bergman A, Taroni A, Hellsvik J, Sanyal B, Eriksson O, Phys. Rev. X, 2, (2012); Mondal R, Rozsa L, Farle M, Oppeneer P M, Nowak U, Cherkasskii M, J. Magn. Magn. Mater, 579, (2023); Dutta S, Siddiqui S A, Currivan-Incorvia J A, Ross C A, Baldo M A, AIP Adv, 5, (2015); Jin T L, Ranjbar M, He S K, Law W C, Zhou T J, Lew W S, Liu X X, Piramanayagam S N, Sci. Rep, 7, (2017); Honda S, Takashima R, Tanaka M, J. Phys. D: Appl. Phys, 52, (2018); Honda S, Itoh H, J. Magn. Soc. Japan, 37, (2013)","S. Honda; Department of Pure and Applied Physics, Kansai University, Suita, 3-3-35 Yamate-cho, 564-8680, Japan; email: shonda@kansai-u.ac.jp","","Institute of Physics","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","","Scopus","2-s2.0-85183963198" +"Gao S.; Du A.; Zhang L.; Li T.-G.; Ma D.-C.","Gao, Sheng (59293721500); Du, An (7006264005); Zhang, Lei (59294045300); Li, Tian-Guang (59293406600); Ma, Da-Cheng (57326136400)","59293721500; 7006264005; 59294045300; 59293406600; 57326136400","Simulation of magnetization process and Faraday effect of magnetic bilayer films","2024","Chinese Physics B","33","9","097505","","","","0","10.1088/1674-1056/ad5a76","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85201765105&doi=10.1088%2f1674-1056%2fad5a76&partnerID=40&md5=43524812a3946ef53b88b556f1148b09","Department of Basic and General Studies, Shenyang Institute of Science and Technology, Shenyang, 110167, China; College of Science, Northeastern University, Shenyang, 110819, China; National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China; Office of Academic Research, Shenyang Institute of Science and Technology, Shenyang, 110167, China; State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China; Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110016, China","Gao S., Department of Basic and General Studies, Shenyang Institute of Science and Technology, Shenyang, 110167, China; Du A., College of Science, Northeastern University, Shenyang, 110819, China, National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China; Zhang L., Office of Academic Research, Shenyang Institute of Science and Technology, Shenyang, 110167, China; Li T.-G., State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang, 110016, China, Institutes for Robotics and Intelligent Manufacturing, Chinese Academy of Sciences, Shenyang, 110016, China; Ma D.-C., College of Science, Northeastern University, Shenyang, 110819, China","We described ferromagnetic film and bilayer films composed of two ferromagnetic layers coupled through antiferromagnetic interfacial interaction by classical Heisenberg model and simulated their magnetization state, magnetic permeability, and Faraday effect at zero and finite temperature by using the Landau-Lifshitz-Gilbert (LLG) equation. The results indicate that in a microwave field with positive circular polarization, the ferromagnetic film has one resonance peak while the bilayer film has two resonance peaks. However, the resonance peak disappears in ferromagnetic film, and only one resonance peak emerges in bilayer film in the negative circularly polarized microwave field. When the microwave field’s frequency exceeds the film’s resonance frequency, the Faraday rotation angle of the ferromagnetic film is the greatest, and it decreases when the thickness of the two halves of the bilayer is reduced. When the microwave field’s frequency remains constant, the Faraday rotation angle fluctuates with temperature in the same manner as spontaneous magnetization does. When a DC magnetic field is applied in the direction of the anisotropic axis of the film, the Faraday rotation angle varies with the DC magnetic field and shows a similar shape of the hysteresis loop. © 2024 Chinese Physical Society and IOP Publishing Ltd.","Faraday effect; hysteresis loop; Landau-Lifshitz-Gilbert (LLG) equation; magnetic bilayer films; magnetic permeability","Antiferromagnetic materials; Circular polarization; Ferromagnetic materials; Ferromagnetic resonance; Film thickness; Hysteresis loops; Magnetic films; Magnetic permeability; Magnetic permeability measurement; Magnetization; Microwave frequencies; Natural frequencies; Bi-layer films; DC magnetic field; Faraday rotation angle; Ferromagnetic bilayers; Ferromagnetic films; Landau-Lifshitz-Gilbert equations; Magnetic bi-layer film; Magnetization process; Microwave field; Resonance peak; Faraday effect","","","","","Shenyang Institute of Science and Technology, (ZD-2024-05)","The research was funded by the Research Program of Shenyang Institute of Science and Technology (Grant No. ZD-2024-05).","Jin H, Physics of Ferromagnerism, (2013); Wang W, Du A, J. Magn. Magn. Mater, 511, (2020); Krichevsky D M, Kalish A N, Kozhaev M A, Sylgacheva D A, Kuzmichev A N, Dagesyan S A, Achanta V G, Popova E, Keller N, Belotelov V I, Phys. Rev. B, 102, (2020); Mihailovic P, Petricevic S, Sensors, 21, (2021); Dadoenkova Y S, Dadoenkova N N, Lyubchanskii I L, Klos J W, Krawczyk M, IEEE Trans. Magn, 53, (2017); Wang H, Han J F, Lei Y Z, Opt. Commun, 492, (2021); Ghorbani-Oranj F, Abdi-Ghaleh R, Roumi B, Jamshidi-Ghaleh K, Madani A, Zhou Y G, Phys. B, (2022); Zhu W Q, Shan W Y, Chin. Phys. B, 32, (2023); Urazhdin S, Loloee R, Pratt W P, Phys. Rev. B, 71, (2005); Wang H, Dai Y Y, Gong W J, Geng D Y, Ma S, Appl. Phys. Lett, 102, (2013); Lisjak D, Mertelj A, Prog. Mater. Sci, 95, (2018); Gutierrez J, Pena A, Barandiaran J M, Pizarro J L, Hernandez T, Lezama L, Insausti M, Rojo T, Phys. Rev. B, 61, (2000); Tartaj P, Morales M P, Gonzalez-Carreno T, Veintemillas-Verdaguer S, Serna C J, J. Magn. Magn. Mater, 290-, (2005); Jamir M, Borgohain C, Borah J P, Phys. 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Spectrosc, 98, (2005); Dmitriew V, Paixao F, Kawakatsu M, Opt. Lett, 38, (2013); Jiang M C, Guo G Y, Phys. Rev. B, 105, (2022); Jin M H, Zheng B, Xiong L, Zhou N J, Wang L, Phys. Rev. E, 98, (2018); Mondal R, Berritta M, Oppeneer P M, Phys. Rev. B, 94, (2016); Gao C X, Farshchi R, Roder C, Dogan P, Brandt O, Phys. Rev. B, 83, (2011); Choi M, Lee S, Kim J, IEEE Trans. Magn, 53, (2017); Alkadour B, Mercer J I, Whitehead J P, Lierop J V, Southern J B, Phys. Rev. B, 93, (2016); Ye Q Y, Wang W J, Deng C C, Chen S Y, Zhang X Y, Wang Y J, Huang Q Y, Huang Z G, Acta Phys. Sin, 68, (2019); Bajpai U, Nikolic B K, Phys. Rev. B, 99, (2019); Liao S B, Ferromagnetism Beijing Science Press 03 in Chinese, (1988); Picco M, Ritort F, Phys. Rev. B, 71, (2005); Cao G J, Wang W, Du A, J. Magn. Magn. Mater, 565, (2023); Youssef J B, Brosseau C, Phys. Rev. B, 74, (2006); Du A, Wei G Z, J. Magn. Magn. Mater, 137, (1994); Song J J, Wang J, Wei D, Takahashi Y K, Hono K, IEEE Trans. Magn, 53, (2017); Wei D, Song J J, Liu C, IEEE Trans. Magn, 52, (2016)","A. Du; College of Science, Northeastern University, Shenyang, 110819, China; email: duan@mail.neu.edu.cn","","Institute of Physics","","","","","","16741056","","","","English","Chin. Phys.","Article","Final","","Scopus","2-s2.0-85201765105" +"Nallan S.; Zhu J.-G.","Nallan, Shreyes (57219327328); Zhu, Jian-Gang (57226007941)","57219327328; 57226007941","Spin Hall Switching Enabled by Uniaxial In-Plane Magnetocrystalline Anisotropy","2023","2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings","","","","","","","0","10.1109/INTERMAGShortPapers58606.2023.10228214","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85172725652&doi=10.1109%2fINTERMAGShortPapers58606.2023.10228214&partnerID=40&md5=3c1f2dd01bf7925a9faab499d1dd1704","Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","Nallan S., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States; Zhu J.-G., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","In this work, we examine spin-orbit-torque magnetic random-access-memory (SOT-MRAM) devices stabilized by in-plane uniaxial magnetocrystalline anisotropy, enabling switching without shape constraints or external fields. We investigate the interaction between uniaxial in-plane anisotropy and the spin-Hall effect in this device - an interaction whose fundamental behavior is currently unknown. We examine switching behavior by performing time-resolved simulations based on the Landau-Lifshitz-Gilbert (LLG) equation, and find strong and tunable dependence on the polarization angle of the incoming spin current, as well as boundaries between stochastic and deterministic switching. Furthermore, we demonstrate an extension of this concept to enable out-of-plane field-free switching. © 2023 IEEE.","LLG equation; magnetocrystalline anisotropy; SOT-MRAM; spin Hall effect","Crystal symmetry; Magnetic recording; Magnetocrystalline anisotropy; MRAM devices; Stochastic systems; External fields; In-plane anisotropy; Landau-Lifshitz-Gilbert equations; Magnetic random access memory; Shape constraints; Spin orbits; Spin-orbit-torque magnetic random-access-memory; Switching behaviors; Time-resolved; Tunables; Spin Hall effect","","","","","","","Liu L., Et al., Spin-torque switching with the giant spin Hall effect of tantalum, Science, 336, 6081, pp. 555-558, (2012); Shao Q., Li P., Liu L., Zhang . W., Roadmap of spin-orbit torques, IEEE Transactions on Magnetics, 57, 7, pp. 1-39, (2021); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Philosophical Transactions of the Royal Society of London, 240, 826, pp. 599-642, (1948); Xiao Y., Wang H., Fullerton E., Crystalline orientation-dependent spin Hall effect in epitaxial platinum, Frontiers in Phys., (2022); Slonczewski J.C., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, 1-2, (1996); Worledge D.C., Theory of spin torque switching current for the double magnetic tunnel junction, IEEE Magnetics Letters, 8, pp. 1-5; Sato N., Xue F., White R.M., Bi C., Wang S.X., Twoterminal spin-orbit torque magnetoresistive random access memory, Nature Electronics, 1, 9, pp. 508-511, (2018)","S. Nallan; Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, United States; email: shreyes@cmu.edu","","Institute of Electrical and Electronics Engineers Inc.","IEEE; Magnetism Society of Japan (MSJ)","2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023","15 May 2023 through 19 May 2023","Sendai","192391","","979-835033836-2","","","English","IEEE Int. Magn. Conf. - Short Pap., INTERMAG Short Papers - Proc.","Conference paper","Final","","Scopus","2-s2.0-85172725652" +"Kraft R.; Koraltan S.; Gattringer M.; Bruckner F.; Suess D.; Abert C.","Kraft, Robert (57221156016); Koraltan, Sabri (57218708417); Gattringer, Markus (57837162100); Bruckner, Florian (44561022400); Suess, Dieter (7004076065); Abert, Claas (55084839600)","57221156016; 57218708417; 57837162100; 44561022400; 7004076065; 55084839600","Parallel-in-time integration of the Landau–Lifshitz–Gilbert equation with the parallel full approximation scheme in space and time","2024","Journal of Magnetism and Magnetic Materials","597","","171998","","","","0","10.1016/j.jmmm.2024.171998","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85189065931&doi=10.1016%2fj.jmmm.2024.171998&partnerID=40&md5=3d685790e9f46d24047923e4f7eb7c6d","Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria; Physics of Functional Materials, University of Vienna, Vienna, Austria; Vienna Doctoral School in Physics, University of Vienna, Vienna, Austria","Kraft R., Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria, Vienna Doctoral School in Physics, University of Vienna, Vienna, Austria; Koraltan S., Physics of Functional Materials, University of Vienna, Vienna, Austria, Vienna Doctoral School in Physics, University of Vienna, Vienna, Austria; Gattringer M., Physics of Functional Materials, University of Vienna, Vienna, Austria, Vienna Doctoral School in Physics, University of Vienna, Vienna, Austria; Bruckner F., Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria, Physics of Functional Materials, University of Vienna, Vienna, Austria; Suess D., Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria, Physics of Functional Materials, University of Vienna, Vienna, Austria; Abert C., Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria, Physics of Functional Materials, University of Vienna, Vienna, Austria","Speeding up computationally expensive problems, such as numerical simulations of large micromagnetic systems, requires efficient use of parallel computing infrastructures. While parallelism across space is commonly exploited in micromagnetics, this strategy performs poorly once a minimum number of degrees of freedom per core is reached. We use magnum.pi, a finite-element micromagnetic simulation software, to investigate the Parallel Full Approximation Scheme in Space and Time (PFASST) as a space- and time-parallel solver for the Landau–Lifshitz–Gilbert equation (LLG). Numerical experiments show that PFASST enables efficient parallel-in-time integration of the LLG, significantly improving the speedup gained from using a given number of cores as well as allowing the code to scale beyond spatial limits. © 2024 The Authors","LLG; Micromagnetics; Parallel-in-time; PFASST","Approximation theory; Computer software; Computing infrastructures; Full approximation schemes; Landau-Lifshitz-Gilbert equations; Micromagnetic systems; Micromagnetics; Parallel com- puting; Parallel full approximation scheme in space and time; Parallel-in-time; Space and time; Time-integration; Degrees of freedom (mechanics)","","","","","Austrian Science Fund, FWF, (P 34671)","This research was funded in whole, or in part, by the Austrian Science Fund (FWF) P 34671 and I 6068 . For the purpose of open access, the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.","Suess D., Schrefl T., Dittrich R., Kirschner M., Dorfbauer F., Hrkac G., Fidler J., Exchange spring recording media for areal densities up to 10Tbit/in2, J. Magn. Magn. Mater., 290-291, pp. 551-554, (2005); Perrissin N., Lequeux S., Strelkov N., Vila L., Buda-Prejbeanu L., Auffret S., Sousa R., Prejbeanu I., Dieny B., Spin transfer torque magnetic random-access memory: Towards sub-10 nm devices, 2018 International Conference on IC Design & Technology, ICICDT, pp. 125-128, (2018); Silva A.V., Leitao D.C., Paz E., Hou Z., Ferreira R., Cardoso S., Freitas P.P., Magneto-transport behavior of double exchange magnetic tunnel junction sensors, 2014 IEEE SENSORS, pp. 718-721, (2014); Sepehri-Amin H., Ohkubo T., Nagashima S., Yano M., Shoji T., Kato A., Schrefl T., Hono K., High-coercivity ultrafine-grained anisotropic Nd–Fe–B magnets processed by hot deformation and the Nd–Cu grain boundary diffusion process, Acta Mater., 61, 17, pp. 6622-6634, (2013); Donahue M., OOMMF User's Guide, Version 1.0, (1999); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., The design and verification of MuMax3, AIP Adv., 4, 10, (2014); Bruckner F., Koraltan S., Abert C., Suess D., magnum.np: a PyTorch based GPU enhanced finite difference micromagnetic simulation framework for high level development and inverse design, Sci. Rep., 13, 1, (2023); Lepadatu S., (2023); Nievergelt J., Parallel methods for integrating ordinary differential equations, Commun. ACM, 7, 12, pp. 731-733, (1964); Lions J.-L., Maday Y., Turinici G., Résolution d'EDP par un schéma en temps ≪pararéel≫, C. R. Acad. Ser. I - Math., 332, 7, pp. 661-668, (2001); Gander M.J., 50 Years of time parallel time integration, Multiple Shooting and Time Domain Decomposition Methods, Contributions in Mathematical and Computational Sciences, pp. 69-113, (2015); Friedhoff S., Falgout R.D., Kolev T.V., MacLachlan S., Schroder J.B., (2012); Emmett M., Minion M., Toward an efficient parallel in time method for partial differential equations, Commun. Appl. Math. Comput. Sci., 7, 1, pp. 105-132, (2012); Fischer P.F., Hecht F., Maday Y., A parareal in time semi-implicit approximation of the Navier-Stokes equations, Domain Decomposition Methods in Science and Engineering, Lecture Notes in Computational Science and Engineering, pp. 433-440, (2005); Legoll F., Lelievre T., Sharma U., An adaptive parareal algorithm: Application to the simulation of molecular dynamics trajectories, SIAM J. Sci. Comput., 44, 1, pp. B146-B176, (2022); Schops S., Niyonzima I., Clemens M., Parallel-in-time simulation of eddy current problems using parareal, IEEE Trans. Magn., 54, 3, pp. 1-4, (2018); Speck R., Ruprecht D., Krause R., Emmett M., Minion M., Winkel M., Gibbon P., Integrating an N-body problem with SDC and PFASST, Domain Decomposition Methods in Science and Engineering XXI, Lecture Notes in Computational Science and Engineering, pp. 637-645, (2014); Gotschel S., Minion M.L., Parallel-in-time for parabolic optimal control problems using PFASST, Domain Decomposition Methods in Science and Engineering XXIV, Lecture Notes in Computational Science and Engineering, pp. 363-371, (2018); Abert C., Micromagnetics and spintronics: models and numerical methods, Eur. Phys. J. B, 92, 6, (2019); Ong B.W., Schroder J.B., Applications of time parallelization, Comput. Vis. Sci., 23, 1, (2020); Abert C., Exl L., Bruckner F., Drews A., Suess D., magnum.fe: A micromagnetic finite-element simulation code based on FEniCS, J. Magn. Magn. Mater., 345, pp. 29-35, (2013); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: Fast micromagnetic simulator for complex magnetic structures (invited), J. Appl. Phys., 109, 7, (2011); Korber L., Quasebarth G., Hempel A., Zahn F., Otto A., Westphal E., Hertel R., Kakay A., TetraX: Finite-element micromagnetic-modeling package, (2022); Rathgeber F., Ham D.A., Mitchell L., Lange M., Luporini F., Mcrae A.T.T., Bercea G.-T., Markall G.R., Kelly P.H.J., Firedrake: Automating the finite element method by composing abstractions, ACM Trans. Math. Software, 43, 3, pp. 241-24:27, (2016); Hindmarsh A.C., Brown P.N., Grant K.E., Lee S.L., Serban R., Shumaker D.E., Woodward C.S., SUNDIALS: Suite of nonlinear and differential/algebraic equation solvers, ACM Trans. Math. Software, 31, 3, pp. 363-396, (2005); Suess D., Tsiantos V., Schrefl T., Fidler J., Scholz W., Forster H., Dittrich R., Miles J.J., Time resolved micromagnetics using a preconditioned time integration method, J. Magn. Magn. Mater., 248, 2, pp. 298-311, (2002); Dutt A., Greengard L., Rokhlin V., Spectral deferred correction methods for ordinary differential equations, BIT Numer. Math., 40, 2, pp. 241-266, (2000); Ruprecht D., Speck R., Spectral deferred corrections with fast-wave slow-wave splitting, SIAM J. Sci. Comput., 38, 4, pp. A2535-A2557, (2016); Huang J., Jia J., Minion M., Accelerating the convergence of spectral deferred correction methods, J. Comput. Phys., 214, 2, pp. 633-656, (2006); Bolten M., Moser D., Speck R., A multigrid perspective on the parallel full approximation scheme in space and time, Numer. Linear Algebra Appl., 24, 6, (2017); Causley M.F., Seal D.C., On the convergence of spectral deferred correction methods, Commun. Appl. Math. Comput. Sci., 14, 1, pp. 33-64, (2019); Weiser M., Faster SDC convergence on non-equidistant grids by DIRK sweeps, BIT Numer. Math., 55, 4, pp. 1219-1241, (2015); Layton A.T., Minion M.L., Implications of the choice of quadrature nodes for picard integral deferred corrections methods for ordinary differential equations, BIT Numer. Math., 45, 2, pp. 341-373, (2005); Henson V.E., 5016, (2002); Koehler F., Pfasst tikz, (2015); Minion M., A hybrid parareal spectral deferred corrections method, Commun. Appl. Math. Comput. Sci., 5, 2, pp. 265-301, (2011); Bolten M., Moser D., Speck R., Asymptotic convergence of the parallel full approximation scheme in space and time for linear problems, Numer. Linear Algebra Appl., 25, 6, (2018); Speck R., Algorithm 997: pySDC–prototyping spectral deferred corrections, ACM Trans. Math. Software, 45, 3, pp. 351-35:23, (2019); Balay S., Abhyankar S., Adams M., Brown J., Brune P., Buschelman K., Dalcin L., Dener A., Eijkhout V., Gropp W., Et al., PETSc Users Manual, (2019); Google Cloud Platform S., Google HPC-toolkit, (2023); Yoo A.B., Jette M.A., Grondona M., SLURM: Simple linux utility for resource management, Job Scheduling Strategies for Parallel Processing, Lecture Notes in Computer Science, pp. 44-60, (2003); Jermain C.L., Rowlands G.E., Buhrman R.A., Ralph D.C., GPU-accelerated micromagnetic simulations using cloud computing, J. Magn. Magn. Mater., 401, pp. 320-322, (2016); Eicke J., μ mag standard problem #4 specification, (2000); Gattringer M., Abert C., Bruckner F., Chumak A., Suess D., Micromagnetically integrated numerical model of spin pumping based on spin diffusion, Phys. Rev. B, 106, (2022); Speck R., Ruprecht D., Minion M., Emmett M., Krause R., Inexact spectral deferred corrections, Domain Decomposition Methods in Science and Engineering XXII, Lecture Notes in Computational Science and Engineering, pp. 389-396, (2016); Speck R., Parallelizing spectral deferred corrections across the method, Comput. Vis. Sci., 19, 3, pp. 75-83, (2018)","R. Kraft; Research Platform MMM Mathematics - Magnetism - Materials, University of Vienna, Vienna, Austria; email: robert.kraft@univie.ac.at","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85189065931" +"Zhao Z.; Zhang L.; Chen Y.; Zhong Z.; Tang X.; Zhang Y.; Zhang H.; Jin L.","Zhao, Zhehao (58863107300); Zhang, Lei (57201265674); Chen, Yufang (58862620600); Zhong, Zhiyong (7402336490); Tang, Xiaoli (57211736614); Zhang, Yuanjing (57215863326); Zhang, Huaiwu (57209556636); Jin, Lichuan (37107863100)","58863107300; 57201265674; 58862620600; 7402336490; 57211736614; 57215863326; 57209556636; 37107863100","Giant anisotropic Gilbert damping and spin wave propagations in single-crystal magnetic insulator","2024","Applied Physics Letters","124","5","052405","","","","3","10.1063/5.0190902","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183977627&doi=10.1063%2f5.0190902&partnerID=40&md5=9701631da0205efd533c7214904b19f4","School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China","Zhao Z., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; Zhang L., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; Chen Y., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; Zhong Z., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; Tang X., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; Zhang Y., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; Zhang H., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; Jin L., School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China","Gilbert damping in magnetic systems describes the relaxation of magnetization. This term was phenomenologically introduced into the Landau-Lifschitz-Gilbert (LLG) equation to describe spin dynamics. In most studies, such as magnetic random access memory, spin-wave propagations, and microwave devices, it has been assumed that the Gilbert damping is an isotropic constant. In this study, we uncover a giant anisotropic Gilbert damping parameter of up to 431% in single-crystal thin films of epitaxial [100]-oriented yttrium iron garnet (YIG) using angle-dependent ferromagnetic resonance. In contrast, the Gilbert damping parameter of a [111]-oriented YIG film is almost isotropic. The observed anisotropic damping is shown to have a similar fourfold symmetry with magneto-crystalline anisotropy. The anisotropic spin-wave group velocity (vg), relaxation time (τ), and decay length (ld) were also experimentally evaluated through spin-wave spectra of [100]-oriented YIG thin film. We developed the LLG equation with the introduction of an anisotropic orbital Gilbert damping term. This anisotropic orbital damping originates from the crystal-field dominated anisotropic spin-orbit coupling and orbital-related magnon-phonon coupling. Our results extend the understanding of the mechanism of anisotropic Gilbert damping in single-crystal magnetic insulators with strong magneto-crystalline anisotropy. © 2024 Author(s).","","Anisotropy; Microwave devices; Random access storage; Single crystals; Spin dynamics; Spin waves; Thin films; Yttrium iron garnet; Gilbert damping; Gilbert damping parameter; Isotropics; Magnetic insulator; Magnetic system; Magneto-crystalline anisotropy; Orbitals; Relaxation of magnetization; Spin-wave propagation; Yttrium iron garnets; Damping","","","","","National Natural Science Foundation of China, NSFC, (62171079, 62171096); National Natural Science Foundation of China, NSFC; National Key Scientific Instrument and Equipment Development Projects of China, (51827802); National Key Scientific Instrument and Equipment Development Projects of China; National Key Research and Development Program of China, NKRDPC, (2022YFA1402802); National Key Research and Development Program of China, NKRDPC","This work was financially supported by the National Key Research and Development Plan under Grant No. 2022YFA1402802, the National Natural Science Foundation of China under Grant Nos. 62171096 and 62171079, and the National Key Scientific Instrument and Equipment Development Project No. 51827802. 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Jin; School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, China; email: lichuanj@uestc.edu.cn","","American Institute of Physics Inc.","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","","Scopus","2-s2.0-85183977627" +"Nishino M.; Miyashita S.","Nishino, Masamichi (7103009415); Miyashita, Seiji (7102333760)","7103009415; 7102333760","Atomistic Model Study on Magnetic Properties of Permanent Magnets—Treatment of Thermal Fluctuation and Thermal Effects, and Future Perspective—","2025","Materials Transactions","66","1","","1","16","15","0","10.2320/matertrans.MT-M2024132","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85213288455&doi=10.2320%2fmatertrans.MT-M2024132&partnerID=40&md5=d76667b81f1812c7587f9a7386961297","National Institute for Materials Science, Tsukuba, 305-0047, Japan; Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan","Nishino M., National Institute for Materials Science, Tsukuba, 305-0047, Japan, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan; Miyashita S., Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan","We review atomistic spin model studies, a new approach for theoretical investigations, on magnetic properties of permanent magnets. In the atomistic modeling, the microscopic details of magnetic parameters and lattice structures are realistically considered, and the temperature effect, including thermal fluctuation, is properly treated based on statistical physics methods: Monte Carlo methods and stochastic Landau-Lifshitz-Gilbert equation methods. We introduce how to treat thermal effects for static and dynamical properties using these methods. Focusing especially on neodymium permanent magnets, we discuss features of magnetization, domain wall, coercivity of a grain, nucleation and pinning fields, and dysprosium substitution effect, which were first elucidated with those methods. ©2024 The Japan Institute of Metals and Materials.","atomistic spin model; Monte Carlo method; permanent magnets; stochastic Landau-Lifshitz-Gilbert (LLG) equation; thermal effects; thermal fluctuation","Magnetic properties; Magnetization; Permanent magnets; Spin dynamics; Spin waves; Statistical optics; Temperature; Atomistic modelling; Atomistic spin model; Atomistics; Landau-Lifshitz-Gilbert equations; MonteCarlo methods; Spin models; Stochastic landau-lifshitz-gilbert equation; Stochastics; Thermal; Thermal fluctuations; Stochastic systems","","","","","Ministry of Education, Culture, Sports, Science and Technology, MEXT; Elements Strategy Initiative Center for Magnetic Materials, (JPMXP0112101004)","The study presented here was supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM) (project number JPMXP0112101004) funded by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. 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Lett, 8, pp. 89-96, (2020); Westmoreland S.C., Evans R.F.L., Hrkac G., Schrel T., Zimanyi G.T., Winklhofer M., Sakuma N., Yano M., Kato A., Shoji T., Manabe A., Ito M., Chantrell R.W., Multiscale model approaches to the design of advanced permanent magnets, Scr. Mater, 148, pp. 56-62, (2018); Westmoreland S.C., Skelland C., Shoji T., Yano M., Kato A., Ito M., Hrkac G., Schrefl T., Evans R.F.L., Chantrell R.W., Atomistic simulations of ¡-Fe/Nd2Fe14B magnetic core/shell nanocomposites with enhanced energy product for high temperature permanent magnet applications, J. Appl. Phys, 127, (2020)","M. Nishino; National Institute for Materials Science, Tsukuba, 305-0047, Japan; email: nishino.masamichi@nims.go.jp","","Japan Institute of Metals (JIM)","","","","","","13459678","","MTARC","","English","Mater. Trans.","Review","Final","","Scopus","2-s2.0-85213288455" +"Bin Hamid S.; Zunaid Baten M.","Bin Hamid, Shafin (58886523100); Zunaid Baten, Md (35742841300)","58886523100; 35742841300","Impact of Process Variation in Spin-Orbit Torque-Based Magnetic Tunnel Junctions on the Performance of Spiking Neural Networks","2024","IEEE Transactions on Electron Devices","71","11","","6672","6679","7","0","10.1109/TED.2024.3456075","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85204638881&doi=10.1109%2fTED.2024.3456075&partnerID=40&md5=2abd468d5da960a37ec6f0e75873ffa2","Bangladesh University of Engineering and Technology (BUET), Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh","Bin Hamid S., Bangladesh University of Engineering and Technology (BUET), Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh; Zunaid Baten M., Bangladesh University of Engineering and Technology (BUET), Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh","Spiking neural network (SNN) with neurons and synapses made of spin-orbit torque (SOT) and domain wall motion-based magnetic tunnel junctions (MTJs) offer a low-power alternative to deep neural networks (DNNs). The present study demonstrates the effect of device-level variations in such neurons and synapses on the performance of a three-layer SNN trained offline using supervised learning and a two-layer SNN trained online using unsupervised spike-timing-dependent plasticity (STDP). The spintronic properties of the neuron and the synapse have been modeled based on the stochastic Landau-Lifshitz-Gilbert (LLG) equation, using macro- and micro-magnetic simulation techniques, respectively. The variations in thickness, saturation magnetization, and damping of the free layer (FL) along with spin Hall angle of the metal have been considered in variability analysis. The results of our analysis show that in both offline and online trained systems, the accuracy of the SNN drops by as much as 20%, for 10% standard deviation of device parameters. The offline trained network is observed to be more sensitive to the variations in neurons located in the output layer. In the online trained network, performance degradation can be traced back to the correlation between the distribution of learned weights and synaptic parameter variation. Among the device parameters considered, the variation in spin Hall angle of the metal layer is observed to have the most significant impact on the performances of the SNNs. © 1963-2012 IEEE.","Magnetic tunnel junction (MTJ); spiking neural network (SNN); spin-orbit torque (SOT); variability","Deep neural networks; Image segmentation; Magnetic domains; Multilayer neural networks; Neurons; Spin dynamics; Spintronics; Device parameters; Magnetic tunnel junction; Neural-networks; Offline; Performance; Spiking neural network; Spin orbits; Spin-orbit torque; Variability; Saturation magnetization","","","","","Bangladesh University of Engineering and Technology, BUET, (r-60/re-4747); Bangladesh University of Engineering and Technology, BUET","Manuscript received 29 July 2024; accepted 4 September 2024. The work of Md Zunaid Baten was supported by the Basic Research through Bangladesh University of Engineering and Technology (BUET) under Grant r-60/re-4747. The review of this article was arranged by Editor P. J. Fay. (Corresponding author: Md Zunaid Baten.) The authors are with the Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology (BUET), Dhaka 1205, Bangladesh (e-mail: mdzunaid@eee.buet.ac.bd).","Khvalkovskiy A.V., Et al., Basic principles of STT-MRAM cell operation in memory arrays, J. Phys. D, Appl. Phys., 46, 7, (2013); Alisha P.B., Warrier D.T.S., Optimizing free layer of magnetic tunnel junction for true random number generator, Memories Mater., Devices, Circuits Syst., 5, (2023); Hamid S.B., Dutta R., Hassan O., Baten M.Z., Implementing bidirectional logic with backhopping in magnetic tunnel junctions, AIP Adv., 14, 2, pp. 1-6, (2024); Sengupta A., Choday S.H., Kim Y., Roy K., Spin orbit torque based electronic neuron, Appl. Phys. Lett., 106, 14, pp. 1-5, (2015); Bhowmik D., Et al., On-chip learning for domain wall synapse based fully connected neural network, J. Magn. Magn. Mater., 489, (2019); Garello K., Et al., Ultrafast magnetization switching by spin-orbit torques, Appl. Phys. Lett., 105, 21, pp. 1-5, (2014); Aradhya S.V., Rowlands G.E., Oh J., Ralph D.C., Buhrman R.A., Nanosecond-timescale low energy switching of in-plane magnetic tunnel junctions through dynamic oersted-field-assisted spin Hall effect, Nano Lett., 16, 10, pp. 5987-5992, (2016); Ramaswamy R., Lee J.M., Cai K., Yang H., Recent advances in spin-orbit torques: Moving towards device applications, Appl. Phys. Rev., 5, 3, (2018); Srinivasan G., Sengupta A., Roy K., Magnetic tunnel junction enabled all-spin stochastic spiking neural network, Proc. Design, Autom. Test Eur. Conf. Exhib. (DATE), pp. 530-535, (2017); Dhull S., Misba W.A., Nisar A., Atulasimha J., Kaushik B.K., Quantized magnetic domain wall synapse for efficient deep neural networks, IEEE Trans. Neural Netw. Learn. Syst., (2024); Gebregiorgis A., Et al., Tutorial on memristor-based computing for smart edge applications, Memories Mater., Devices, Circuits Syst., 4, (2023); Asifuzzaman K., Miniskar N.R., Young A.R., Liu F., Vetter J.S., A survey on processing-in-memory techniques: Advances and challenges, Memories Mater., Devices, Circuits Syst., 4, (2023); Suri M., Et al., Phase change memory as synapse for ultradense neuromorphic systems: Application to complex visual pattern extraction, IEDM Tech. Dig., pp. 441-444, (2011); Lashkare S., Chouhan S., Chavan T., Bhat A., Kumbhare P., Ganguly U., PCMO RRAM for integrate-and-fire neuron in spiking neural networks, IEEE Electron Device Lett., 39, 4, pp. 484-487, (2018); Boyn S., Et al., Learning through ferroelectric domain dynamics in solidstate synapses, Nature Commun., 8, 1, (2017); Hameed R., Et al., Understanding sources of inefficiency in generalpurpose chips, Proc. 37th Annu. Int. Symp. Comput. Archit., pp. 37-47, (2010); Rajendran B., Sebastian A., Schmuker M., Srinivasa N., Eleftheriou E., Low-power neuromorphic hardware for signal processing applications: A review of architectural and system-level design approaches, IEEE Signal Process. Mag., 36, 6, pp. 97-110, (2019); Sengupta A., Parsa M., Han B., Roy K., Probabilistic deep spiking neural systems enabled by magnetic tunnel junction, IEEE Trans. Electron Devices, 63, 7, pp. 2963-2970, (2016); Sengupta A., Shim Y., Roy K., Proposal for an all-spin artificial neural network: Emulating neural and synaptic functionalities through domain wall motion in ferromagnets, IEEE Trans. Biomed. Circuits Syst., 10, 6, pp. 1152-1160, (2016); Song J., Dixit H., Behin-Aein B., Kim C.H., Taylor W., Impact of process variability on write error rate and read disturbance in STT-MRAM devices, IEEE Trans. Magn., 56, 12, pp. 1-11, (2020); Sehgal A., Das K.K., Dhull S., Roy S., Kaushik B.K., Variability analysis of multilevel spin-orbit torque MRAMs using machine learning, Proc. IEEE 23rd Int. Conf. Nanotechnol. (NANO), pp. 793-797, (2023); Dutta R., Et al., Experimental and theoretical investigation of intracell magnetic coupling-induced variability of spin-transfer torque magnetic RAMs, IEEE Trans. Electron Devices, 70, 10, pp. 5428-5434, (2023); Deng L., The MNIST database of handwritten digit images for machine learning research, IEEE Signal Process. Mag., 29, 6, pp. 141-142, (2012); Diehl P.U., Cook M., Unsupervised learning of digit recognition using spike-timing-dependent plasticity, Front. Comput. Neurosci., 9, (2015); Pai C.-F., Liu L., Li Y., Tseng H.W., Ralph D.C., Buhrman R.A., Spin transfer torque devices utilizing the giant spin Hall effect of tungsten, Appl. Phys. Lett., 101, 12, (2012); Ghosh-Dastidar S., Adeli H., Spiking neural networks, Int. J. Neural Syst., 19, 4, pp. 295-308, (2009); Wang Z., Zhao W., Deng E., Klein J.-O., Chappert C., Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque, J. Phys. D, Appl. Phys., 48, 6, (2015); Wang Y., Deorani P., Qiu X., Kwon J.H., Yang H., Determination of intrinsic spin Hall angle in Pt, Appl. Phys. Lett., 105, 15, pp. 1-4, (2014); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., The design and verification of MuMax3, AIP Adv., 4, 10, pp. 1-22, (2014); Paszke A., Et al., PyTorch: An imperative style, high-performance deep learning library, Proc. Adv. Neural Inf. Process. Syst., 32, pp. 8026-8037, (2019); Xie Y., Behin-Aein B., Ghosh A.W., Fokker-Planck study of parameter dependence on write error slope in spin-torque switching, IEEE Trans. Electron Devices, 64, 1, pp. 319-324, (2017); Bhatti S., Sbiaa R., Hirohata A., Ohno H., Fukami S., Piramanayagam S., Spintronics based random access memory: A review, Mater. Today, 20, 9, pp. 530-548, (2017); Yuasa S., Djayaprawira D.D., Giant tunnel magnetoresistance in magnetic tunnel junctions with a crystalline MgO(0 0 1) barrier, J. Phys. D, Appl. Phys., 40, 21, pp. R337-R354, (2007); Gosavi T.A., Et al., Experimental demonstration of efficient spin-orbit torque switching of an MTJ with sub-100 ns pulses, IEEE Trans. Magn., 53, 9, pp. 1-7, (2017); Sikder B., Et al., Analysis and simulation of interface quality and defect induced variability in MgO spin-transfer torque magnetic RAMs, IEEE Electron Device Lett., 42, 1, pp. 34-37, (2021); Thomas S.A., Sharma R., Das D.M., Analyzing the impact of parasitics on a CMOS-memristive crossbar neural network based on winner-take-all and Hebbian rule, Memories Mater., Devices, Circuits Syst., 5, (2023)","M. Zunaid Baten; Bangladesh University of Engineering and Technology (BUET), Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh; email: mdzunaid@eee.buet.ac.bd","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-85204638881" +"Bonda A.; Uba L.; Uba S.","Bonda, A. (55245823600); Uba, L. (6701773764); Uba, S. (6603542725)","55245823600; 6701773764; 6603542725","Magnetization dynamics in layered systems with coexisting bilinear and biquadratic interlayer exchange coupling","2023","Physical Review B","107","14","144408","","","","2","10.1103/PhysRevB.107.144408","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85152122343&doi=10.1103%2fPhysRevB.107.144408&partnerID=40&md5=a1282d322536530a1310f8a51b5bc651","Faculty of Physics, University of Bialystok, K. Ciolkowskiego 1L, Bialystok, 15-245, Poland","Bonda A., Faculty of Physics, University of Bialystok, K. Ciolkowskiego 1L, Bialystok, 15-245, Poland; Uba L., Faculty of Physics, University of Bialystok, K. Ciolkowskiego 1L, Bialystok, 15-245, Poland; Uba S., Faculty of Physics, University of Bialystok, K. Ciolkowskiego 1L, Bialystok, 15-245, Poland","Important aspects of exchange-coupled magnetic layered structures are related to the noncollinear arrangement of sublayer magnetizations which can arise from competition between bilinear (BL) and biquadratic (BQ) interlayer exchange coupling (IEC). In this work, the influence of coexisting BL and BQ IEC of different strengths on magnetization precession in layered systems is investigated both experimentally and theoretically. Laser-induced magnetization precession has been studied in the Fe/Si(dSi) multilayers (MLS) as a function of the amplitude (H) and orientation angle (θH) of external magnetic field using time-resolved magneto-optical Kerr (TRMOKE) effect. Strongly changing characters of precession frequency dependencies ω(H,θH) for Fe sublayer thickness dFe=3 nm and Si spacer-layer thicknesses (dSi) varying in the range of 0.9-2.4 nm have been observed. Analytical formulas for acoustic and optic mode dispersion relations with coexisting BL and BQ IEC, scaled by J1 and J2 parameters, respectively, for the in-plane effective magnetic anisotropy and arbitrary magnetic field direction were derived, and very good agreement with the experimentally observed frequency dependencies has been obtained. It is shown that BQ coexisting with BL IEC significantly influences on the magnitude and form of dispersion relations. From analytical formula derived, it follows that zero-field optical mode frequency tends to zero as |J1| approaches 2J2. The acoustic and optic mode-crossing effect has been observed and it is found that values of crossing fields and frequency gaps strongly increase as θH angles decrease and depend on relative BL and BQ IEC strengths. The BL IEC is of ferromagnetic type with J1≈1.6 mJ/m2 for the MLS with dSi=0.9 nm, and changes to antiferromagnetic one with J1≈-0.9 mJ/m2 for the MLS with dSi=1.4 nm, while the J2 parameter of BQ IEC decreases from 1.8 to 1.0 mJ/m2. The coupling strengths decrease by one to two orders of magnitude for the sample with dSi=2.4 nm, but both mode frequencies are still observed and well reproduced by the theory. It is shown that J1 and J2 parameters obtained in the TRMOKE experiment coincide within the estimated error bars with the determined from independent measurements of magnetization processes in the static magneto-optical Kerr effect and interpreted with the use of analytical formulas derived. Numerical solutions of coupled Landau-Lifshitz-Gilbert (LLG) equations for acoustic and optic modes, with inclusion of BL IEC, intrinsic Gilbert damping, and spin-pumping damping terms, and extended to include BQ IEC, were performed and fitted to experimental data. It is shown that determined effective damping coefficients on H and θH dependencies for acoustic and optic modes are very well simulated with the use of LLG equation solutions with Gilbert damping, spin-pumping-damping-related effective spin-mixing conductance, and spin-diffusion length parameters included. The dependencies of the parameters on dSi spacer-layer thickness are discussed and compared with available data for other systems. © 2023 American Physical Society.","","Acoustic fields; Dispersion (waves); Dispersions; Magnetic anisotropy; Magnetic fields; Quantum theory; Analytical formulas; Dispersion relations; Frequency dependencies; Interlayer exchange coupling; Landau-Lifshitz-Gilbert equations; Layered systems; Magnetization precession; Mode frequencies; Optic modes; Spacer layer thickness; Magnetization","","","","","Narodowe Centrum Nauki, NCN, (2019/03/X/ST3/01500)","Authors would like to thank T. Luciński and P. Chomiuk for providing samples for MOKE and TRMOKE measurements. The calculations were performed in part in Computational Centre of University in Bialystok. This work was supported by the National Science Centre in Poland, Grant No. 2019/03/X/ST3/01500.","Grunberg P., Schreiber R., Pang Y., Brodsky M. 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Appl, 13, (2020); Sud A., Koike Y., Iihama S., Zollitsch C., Mizukami S., Kurebayashi H., Parity-controlled spin-wave excitations in synthetic antiferromagnets, Appl. Phys. Lett, 118, (2021); Slonczewski J. C., Origin of biquadratic exchange in magnetic multilayers (invited), J. Appl. Phys, 73, (1993); Varnakov S. N., Komogortsev S. V., Ovchinnikov S. G., Bartolome J., Sese J., Magnetic properties and nonmagnetic phases formation in (Fe/Si)(Equation presented) films, J. Appl. Phys, 104, (2008); Dai C., Ma F., Strong magnon-magnon coupling in synthetic antiferromagnets, Appl. Phys. Lett, 118, (2021); Chen X., Zheng C., Zhou S., Liu Y., Zhang Z., Manipulation of time-and frequency-domain dynamics by magnon-magnon coupling in synthetic antiferromagnets, Magnetochemistry, 8, (2022); Mizukami S., Suzuki K. Z., Miura Y., All-optical probe of sub-THz spin precession in a (Equation presented) MnGa nanolayer, Appl. Phys. Express, 12, (2019); Bonda A., Uba S., Uba L., Dubowik J., Influence of magnetic field orientation on laser-induced magnetization precession in Ni-Mn-Sn Heusler alloy film, J. Magn. Magn. Mater, 504, (2020); Zhang Y., Wu G., Ji Z., Chen X., Jin Q. Y., Zhang Z., Significant and Nonmonotonic Dynamic Magnetic Damping in Asymmetric (Equation presented) Trilayers, Phys. Rev. Appl, 17, (2022); Hamaya K., Hashimoto N., Oki S., Yamada S., Miyao M., Kimura T., Estimation of the spin polarization for Heusler-compound thin films by means of nonlocal spin-valve measurements: Comparison of (Equation presented) and (Equation presented), Phys. Rev. B, 85, (2012); Tanikawa K., Oki S., Yamada S., Mibu K., Miyao M., Hamaya K., Effect of Co-Fe substitution on room-temperature spin polarization in (Equation presented) Heusler-compound films, Phys. Rev. B, 88, (2013); Iihama S., Mizukami S., Naganuma H., Oogane M., Ando Y., Miyazaki T., Gilbert damping constants of Ta/CoFeB/MgO(Ta) thin films measured by optical detection of precessional magnetization dynamics, Phys. Rev. B, 89, (2014); Iihama S., Sakuma A., Naganuma H., Oogane M., Mizukami S., Ando Y., Influence of (Equation presented) order parameter on Gilbert damping constants for FePd thin films investigated by means of time-resolved magneto-optical Kerr effect, Phys. Rev. B, 94, (2016); Capua A., Yang S.-h., Phung T., Parkin S. S. P., Determination of intrinsic damping of perpendicularly magnetized ultrathin films from time-resolved precessional magnetization measurements, Phys. Rev. B, 92, (2015); Lattery D. M., Zhang D., Zhu J., Hang X., Wang J.-P., Wang X., Low Gilbert damping constant in perpendicularly magnetized W/CoFeB/MgO films with high thermal stability, Sci. Rep, 8, (2018); Hurben M. J., Patton C. E., Theory of two magnon scattering microwave relaxation and ferromagnetic resonance linewidth in magnetic thin films, J. Appl. Phys, 83, (1998); Barati E., Cinal M., Edwards D. M., Umerski A., Gilbert damping in magnetic layered systems, Phys. Rev. B, 90, (2014); Azzawi S., Ganguly A., Tokac M., Rowan-Robinson R. M., Sinha J., Hindmarch A. T., Barman A., Atkinson D., Evolution of damping in ferromagnetic/nonmagnetic thin film bilayers as a function of nonmagnetic layer thickness, Phys. Rev. B, 93, (2016); Liu Y., Yuan Z., Wesselink R. J. H., Starikov A. A., Kelly P. J., Interface Enhancement of Gilbert Damping from First Principles, Phys. Rev. Lett, 113, (2014); King J. A., Ganguly A., Burn D. M., Pal S., Sallabank E. A., Hase T. P. A., Hindmarch A. T., Barman A., Atkinson D., Local control of magnetic damping in ferromagnetic/non-magnetic bilayers by interfacial intermixing induced by focused ion-beam irradiation, Appl. Phys. Lett, 104, (2014); Ganguly A., Azzawi S., Saha S., King J. A., Rowan-Robinson R. M., Hindmarch A. T., Sinha J., Atkinson D., Barman A., Tunable magnetization dynamics in interfacially modified (Equation presented)/Pt bilayer thin film microstructures, Sci. Rep, 5, (2015); Woltersdorf G., Buess M., Heinrich B., Back C. H., Time Resolved Magnetization Dynamics of Ultrathin Fe(001) Films: Spin-Pumping and Two-Magnon Scattering, Phys. Rev. Lett, 95, (2005); Conca A., Keller S., Schweizer M. R., Papaioannou E. T., Hillebrands B., Separation of the two-magnon scattering contribution to damping for the determination of the spin mixing conductance, Phys. Rev. B, 98, (2018); Xu Z., Zhang K., Li J., Disentangling intrinsic and extrinsic Gilbert damping, Phys. Rev. B, 104, (2021); Zakeri K., Lindner J., Barsukov I., Meckenstock R., Farle M., von Horsten U., Wende H., Keune W., Rocker J., Kalarickal S. S., Lenz K., Kuch W., Baberschke K., Frait Z., Spin dynamics in ferromagnets: Gilbert damping and two-magnon scattering, Phys. Rev. B, 76, (2007); Zakeri K., Lindner J., Barsukov I., Meckenstock R., Farle M., von Horsten U., Wende H., Keune W., Rocker J., Kalarickal S. S., Lenz K., Kuch W., Baberschke K., Frait Z., Erratum: Spin dynamics in ferromagnets: Gilbert damping and two-magnon scattering [Phys. Rev. B 76, 104416 (2007)], Phys. Rev. B, 80, (2009)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85152122343" +"Sen M.; Barman S.","Sen, Madhurima (58990234500); Barman, Saswati (7102545568)","58990234500; 7102545568","Optimization of Spin-Polarized Current Induced Domain Wall Velocity in a Magnetic Nano Stripe Using Sinc Pulse—A Computational Study","2024","Physics of the Solid State","66","8","","235","244","9","0","10.1134/S1063783424600572","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85203264119&doi=10.1134%2fS1063783424600572&partnerID=40&md5=f09f5c3b122600c3e81062d820d732ba","Department of Basic Science and Humanities, Institute of Engineering and Management, Salt Lake Electronics Complex, Sector V, Salt Lake, Kolkata, 700091, India; University of Engineering and Management, University Area, Plot no. III, B/5, New Town Road, Action Area III, Newtown, Kolkata, 700160, India","Sen M., Department of Basic Science and Humanities, Institute of Engineering and Management, Salt Lake Electronics Complex, Sector V, Salt Lake, Kolkata, 700091, India, University of Engineering and Management, University Area, Plot no. III, B/5, New Town Road, Action Area III, Newtown, Kolkata, 700160, India; Barman S., Department of Basic Science and Humanities, Institute of Engineering and Management, Salt Lake Electronics Complex, Sector V, Salt Lake, Kolkata, 700091, India, University of Engineering and Management, University Area, Plot no. III, B/5, New Town Road, Action Area III, Newtown, Kolkata, 700160, India","Abstract: Domain wall propagation and domain wall structure in spin dynamics play a crucial role in the development of new efficient memory devices. A transverse domain wall in the finite straight permalloy nanostrip has been investigated by applying the different normalized sinc current pulses and observing its motion. In addition, it has been observed that domain wall velocity gradually increases with the increase of the pulse period of the sinc pulse current. Furthermore, the pulse scale plays another crucial role in improving the domain wall velocity. Domain Wall velocity can be increased again by changing the non-adiabatic parameter. This study has successfully found the optimal values of the non-adiabatic parameter β and a scaler factor k that can be multiplied to pulse scale resulting in the highest domain wall velocity in particularly low current. It significantly established another control mechanism on the domain wall by varying the pulse scale and pulse period of the sinc pulse current. The present work shows that domain wall motion inside magnetic nano strips may be controlled with high efficiency and reliability using spin-polarized current pulse by solving the LLG equation and the object oriented micromagnetic framework (OOMMF) simulator. The development of racetrack memory technologies with enhanced data storing capacity will be significantly impacted by this study. © Pleiades Publishing, Ltd. 2024. ISSN 1063-7834, Physics of the Solid State, 2024, Vol. 66, No. 8, pp. 235–244. Pleiades Publishing, Ltd., 2024.","domain wall dynamics; magnetic nano stripe; micromagnetic simulation; OOMMF; sinc current pulse","","","","","","University of Engineering and Management, Kolkata; Institute of Engineering and Management, Kolkata; Science and Engineering Research Board, SERB, (CRG/2018/002080)","S.B. acknowledges financial support from the Science and Engineering Research Board (SERB), Govt. of India under (grant no. CRG/2018/002080). The authors also want to acknowledge the Institute of Engineering and Management Kolkata for providing the necessary infrastructural facilities. M.S. acknowledges the University of Engineering and Management, Kolkata, and the Institute of Engineering and Management, Kolkata for financial assistance and infrastructural facilities. ","Hayashi M., Thomas L., Moriya R., Rettner C., Parkin S.S., Science, 320, (2008); Daughton J.M., Huang J.S., Magnetoresistive Memory Including Thin Film Storage Cells Having Tapered Ends, 4; Bhatti S., Sbiaa R., Hirohata A., Ohno H., Fukami S., Piramanayagam S.N., Mater. Today, 20, (2017); Parkin S.S., Hayashi M., Thomas L., Science, 320, (2008); Parkin S., Yang S.H., Nat. Nanotechnol, 10, (2015); Blasing R., Khan A.A., Filippou P.C., Garg C., Hameed F., Castrillon J., Parkin S.S., Proc. IEEE, 108, (2020); Xu Y., Thompson S., Spintronic Materials and Technology, (2006); Boulle O., Malinowski G., Klaui M., Mater. Sci. Eng: Rep, 72, (2011); Kim K.J., Yoshimura Y., Ono T., Jpn. J. Appl. Phys, 56, 8, (2017); Zhukova V., Ipatov M., Zhukov A., Sensors, 9, (2009); Tan F.N., Gan W.L., Ang C.C., Wong G.D., Liu H.X., Poh F., Lew W.S., Sci. Rep, 9, (2019); Wang X.R., Yan P., Lu J., He C., Ann. Phys, 324, (2009); Goolaup S., Low S.C., Sekhar M.C., Lew W.S., J. Phys.: Conf. Ser., 266, 1, (2011); Gao Y., You B., Ruan X.Z., Liu M.Y., Yang H.L., Zhan Q.F., Li Z., Lei N., Zhao W.S., Pan D.F., Wan J.G., Sci. Rep, 6, (2016); Yuan H.Y., Wang X.R., Phys. Rev. B, 92, 5, (2015); Roxy K., Longofono S., Olliver S., Bhanja S., Jones A.K., IEEE Trans. Circuits Syst. II: Express Briefs, 69, (2022); Ravelosona D., Mangin S., Lemaho Y., Katine J.A., Terris B.D., Fullerton E.E., Phys. Rev. Lett, 96, 18, (2006); Klaui M., Vaz C.A., Bland J.A., Wernsdorfer W., Faini G., Cambril E., Heyderman L.J., Appl. Phys. Lett, 83, (2003); Khvalkovskiy A.V., Zvezdin K.A., Gorbunov Y.V., Cros V., Grollier J., Fert A., Zvezdin A.K., Phys. Rev. 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B, 77, 21, (2008); Hals K.M., Nguyen A.K., Brataas A., Phys. Rev. Lett, 102, 25, (2009); Xiao J., Zangwill A., Stiles M.D., Phys. Rev. B, 73, 5, (2006); Ohe J.I., Kramer B., Phys. Rev. Lett, 96, 2, (2006); Landau L., Lifshitz W., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., Phys. Rev, 100, (1955); Atkinson D., Allwood D.A., Xiong G., Cooke M.D., Faulkner C.C., Cowburn R.P., Nat. Mater, 2, (2003); Beach G.S.D., Tsoi M., Erskine J.L., J. Magn, Magn. Mater, 320, (2008); Beach G.S.D., Knutson C., Nistor C., Tsoi M., Erskine J.L., Phys. Rev. Lett, 97, 5, (2006); Pollard S.D., Huang L., Buchanan K.S., Arena D.A., Zhu Y., Nat. Commun, 3, (2012); De Ranieri E., Roy P.E., Fang D., Vehsthedt E.K., Irvine A.C., Heiss D., Casiraghi A., Campion R.P., Gallagher B.L., Jungwirth T., Wunderlich J., Nat. Mater, 12, (2013); Barman S., Ganguly A., Barman A., Spin, 3, 1, (2013); Lim C.K., Devolder T., Chappert C., Grollier J., Cros V., Vaures A., Fert A., Faini G., Appl. Phys. Lett, 84, (2004); Donahue M., Porter D.G., OOMMF User’s Guide 1999 Version 1.0, Interagency Report NISTIR 6376, (1999); Meo A., Cronshaw C.E., Jenkins S., Winterburn A., Evans R.F.L., (2022); Tatara G., Takayama T., Kohno H., Shibata J., Nakatani Y., Fukuyama H., J. Phys. Soc. Jpn, 75, 6, (2006); Tatara G., Kohno H., Shibata J., J. Phys. Soc. Jpn, 77, 3, (2008); Bran C., Fernandez-Roldan J.A., Moreno J.A., Rodriguez A.F., Del Real R.P., Asenjo A., Saugar E., Marques-Marchan J., Mohammed H., Foerster M., Aballe L., Nanoscale, 15, (2023); Corodeanu S., Chiriac H., Damian A., Lupu N., Ovari T.A., Sci. Rep, 9, (2019); Miron I.M., Moore T., Szambolics H., Buda-Prejbeanu L.D., Auffret S., Rodmacq B., Pizzini S., Vogel J., Bonfim M., Schuhl A., Gaudin G., G, Nat. Mater, 10, (2011); Hayashi M., Thomas L., Rettner C., Moriya R., Bazaliy Y.B., Parkin S.S., Phys. Rev. Lett, 98, 3, (2007); Lim C.K., Devolder T., Chappert C., Grollier J., Cros V., Vaures A., Fert A., Faini G., Appl. Phys. Lett, 84, (2004); Gan L., Chung S.H., Aschenbach K.H., Dreyer M., Gomez R.D., IEEE Trans. Magn, 36, (2000)","S. Barman; Department of Basic Science and Humanities, Institute of Engineering and Management, Kolkata, Salt Lake Electronics Complex, Sector V, Salt Lake, 700091, India; email: saswati.barman@iem.edu.in","","Pleiades Publishing","","","","","","10637834","","","","English","Phys. Solid State","Article","Final","","Scopus","2-s2.0-85203264119" +"Maniotis N.","Maniotis, N. (57192182697)","57192182697","Studying the rate-dependent specific absorption rate in magnetic hyperthermia through multiscale simulations","2023","AIP Advances","13","6","065122","","","","2","10.1063/5.0147924","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85163195754&doi=10.1063%2f5.0147924&partnerID=40&md5=33b230609c90750fece757cbeac19698","School of Physics, Faculty of Sciences, Aristotle University, Thessaloniki, Greece and MagnaCharta, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki, Greece","Maniotis N., School of Physics, Faculty of Sciences, Aristotle University, Thessaloniki, Greece and MagnaCharta, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki, Greece","In this work, the issue of whether the dynamic magnetic properties of monodispersed magnetic colloids, modeled using micromagnetic simulations, can be extrapolated to analyze magnetic particle hyperthermia data, i.e., specific absorption rate (SAR) values acquired at high frequencies of excitation fields, is addressed. Micromagnetic finite difference simulations were performed using the Object Oriented Micromagnetic Framework (OOMMF) software package in order to obtain the dynamic hysteresis loops under a 24 kA/m alternating magnetic field amplitude and for various frequencies (50-765 kHz). In OOMMF, the finite difference method was used to find the solution of the nonlinear Landau-Lifshitz Gilbert (LLG) equation, which describes the nanoparticles’ magnetization motion when applying an effective magnetic field. To create a system of randomly oriented magnetite nanoparticles having a certain volume fraction (0.02%) that coincides with the experimentally utilized concentration of 1 mg/ml, we start with a perfect simple cubic lattice with a large lattice spacing so that the particle-particle distance is large enough to neglect dipolar interactions (non-interacting nanoparticles). The system under study is a set of 40-nm magnetite nanoparticles with a lognormal size distribution. The simulations were performed assuming quasistatic conditions, an approach that is reasonable for ferromagnetic-like behavior. It is worth noting that the code considers not only the uniaxial anisotropy Ku but also the cubic magnetocrystalline one Kc as well. Kc is usually neglected in literature because the uniaxial contribution dominates, but this is not the case for magnetite since Ku = 9 kJ/m3 and Kc = −11 kJ/m3. Moreover, such an inclusion seems quite reasonable since the magnetocrystalline anisotropy is always present yet with a relative contribution. The SAR values at each frequency were determined after calculating hysteresis losses via the area of the simulated hysteresis loops. Interestingly, SAR values at low frequencies followed an exponential increase trend with a frequency indicating a deviation from the linear behavior usually reported in the literature. To validate our approach, we employed a coupled electromagnetic-thermal model based on COMSOL Multiphysics simulations that provides an accurate estimation of the magnetic field and temperature distribution within the ferrofluid. The time-dependent temperature curves are obtained after 30 min of magnetic particle hyperthermia treatment for the same alternating magnetic field amplitude used in OOMMF simulations (30 mT) and for two representative frequency values. One in the low (300 kHz) and one in the high (765 kHz) frequency regimes. The numerical curves were compared to the corresponding experimental ones and found to be in good agreement. Our findings provide new insight into the validity of dynamic micromagnetic simulation to analyze the frequency behavior of SAR within the framework of LLG and indicate that anisotropy selection plays a key role in the reliability of simulations. © 2023 Author(s).","","Hyperthermia therapy; Hysteresis; Hysteresis loops; Kurchatovium; Magnetic field effects; Magnetic fluids; Magnetite; Nanomagnetics; Nonlinear equations; Saturation magnetization; Alternating magnetic field; Magnetic field amplitudes; Magnetic hyperthermia; Magnetic particle; Magnetic-field; Micromagnetic simulations; Micromagnetics; Object oriented; Rate dependent; Specific absorption rate; Magnetite nanoparticles","","","","","","","Angelakeris M., Biochim. Biophys. Acta, Gen. Subj., 1861, (2017); Simeonidis K., Martinez-Boubeta C., Serantes D., Ruta S., Chubykalo-Fesenko O., Chantrell R., Oro-Sole J., Balcells L., Kamzin A.S., Nazipov R.A., Makridis A., Angelakeris M., ACS Appl. Nano Mater., 3, (2020); Bertotti G., Electromagnetism, (1998); Conde-Leboran I., Baldomir D., Martinez-Boubeta C., Chubykalo-Fesenko O., Del Puerto Morales M., Salas G., Cabrera D., Camarero J., Teran F.J., Serantes D., J. Phys. Chem. C., 119, (2020); Donahue M.J., Porter D.G., (2002); Dutz S., Hergt R., Nanotechnology, 25, (2014); Leliaert J., Mulkers J., J. Appl. Phys., 125, (2019); Vallejo-Fernandez G., O'Grady K., Appl. Phys. Lett., 103, (2013); Maniotis N., Nazlidis A., Myrovali E., Makridis A., Angelakeris M., Samaras T., J. Appl. Phys., 125, (2019); Bjork R., Poulsen E.B., Nielsen K.K., Insinga A.R., J. Magn. Magn. Mater., 535, (2022); Schrefl T., Fidler J., Suess D., Tsiantos V., T. Schrefl, J. Fidler, D. Suess and V. D. Tsiantos, Micromagnetic simulation of dynamic and thermal effects, Handbook of Advanced Magnetic Materials, pp. 128-146, (2006); Maier-Hauff K., Ulrich F., Nestler D., Niehoff H., Wust P., Thiesen B., Orawa H., Budach V., Jordan A., J. Neurooncol., 103, (2011); Jordan A., Scholz R., Maier-Hauff K., Johannsen M., Wust P., Nadobny J., Schirra H., Schmidt H., Deger S., Loening S., Lanksch W., Felix R., J. Magn. Magn. Mater., 225, (2001); Perigo E.A., Hemery G., Sandre O., Ortega D., Garaio E., Plazaola F., Teran F.J., Appl. Phys. Rev., 2, 4, (2015); Carrey J., Mehdaoui B., Respaud M., J. Appl. Phys., 109, (2011); Usov N.A., Grebenshchikov Y.B., J. Appl. Phys., 106, (2009); Shah R.R., Davis T.P., Glover A.L., Nikles D.E., Brazel C.S., J. Magn. Magn. Mater., 387, (2015); Liu N.N., Pyatakov A.P., Zharkov M.N., Pyataev N.A., Sukhorukov G.B., Alekhina Y.A., Perov N.S., Gun'ko Y.K., Tishin A.M., Appl. Phys. Lett., 120, 10, (2022); COMSOL Multiphysics ® V E R S I O N 3. 5 a, (1998); Cobianchi M., Guerrini A., Avolio M., Innocenti C., Corti M., Arosio P., Orsini F., Sangregorio C., Lascialfari A., J. Magn. Magn. Mater., 444, (2017); Perigo E.A., Hemery G., Sandre O., Ortega D., Garaio E., Plazaola F., Teran F.J., Magnetic Materials and Technologies for Medical Applications, 1st ed.,, (2021); Hosu O., Tertis O., Cristea C., Magnetochemistry, 5, (2019); Socoliuc V., Peddis D., Petrenko V.I., Avdeev M.V., Susan-Resiga D., Szabo T., Turcu R., Tombacz E., Vekas L., Magnetochemistry, 6, (2020); Spirou S., Basini M., Lascialfari A., Sangregorio C., Innocenti C., Nanomaterials, 8, (2018); Usov N.A., Nesmeyanov M.S., Gubanova E.M., Epshtein N.B., Beilstein J. Nanotechnol., 10, (2019)","N. Maniotis; School of Physics, Faculty of Sciences, Aristotle University, Thessaloniki, Greece and MagnaCharta, Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Thessaloniki, Greece; email: nimaniot@physics.auth.gr","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85163195754" +"Gao Q.; Fordham M.E.; Cui H.; Wang Y.E.","Gao, Qian (57933348400); Fordham, Mason Ernest (57221605335); Cui, Han (55774086800); Wang, Yuanxun Ethan (57202387207)","57933348400; 57221605335; 55774086800; 57202387207","A Compact Circuit Model for Frequency-Selective Limiters With Strong Field Nonuniformity","2023","IEEE Transactions on Microwave Theory and Techniques","71","12","","5124","5134","10","2","10.1109/TMTT.2023.3285449","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85163427056&doi=10.1109%2fTMTT.2023.3285449&partnerID=40&md5=b52e419271e8c83bc27caf20722157a2","University of California at Los Angeles, Electrical and Computer Engineering Department, Los Angeles, 90095, CA, United States; University of Tennessee, Knoxville, University of Tennessee Knoxville, Min H. Kao Department of Electrical Engineering and Computer Science, Knoxville, 37996, TN, United States","Gao Q., University of California at Los Angeles, Electrical and Computer Engineering Department, Los Angeles, 90095, CA, United States; Fordham M.E., University of California at Los Angeles, Electrical and Computer Engineering Department, Los Angeles, 90095, CA, United States; Cui H., University of Tennessee, Knoxville, University of Tennessee Knoxville, Min H. Kao Department of Electrical Engineering and Computer Science, Knoxville, 37996, TN, United States; Wang Y.E., University of California at Los Angeles, Electrical and Computer Engineering Department, Los Angeles, 90095, CA, United States","A compact nonlinear circuit model is developed for frequency-selective limiters (FSLs) based on thin film magnetic materials. The model contains a three-port coupled inductor circuit called a spin unit that represents the dynamic spin precession behaviors of a single spin, which is derived rigorously from the Landau-Lifshitz-Gilbert (LLG) equation. The spin units are then combined with external circuitry to represent the coupling between the RF signal in the form of electromagnetic (EM) waves and the spin waves. Specifically, two types of coupling are considered, parallel pumping and perpendicular pumping. The former contributes to the power-limiting effects of FSLs, while the latter accounts for the small signal insertion loss. In addition, the RF magnetic fields provided by coplanar waveguide (CPW)-FSLs are spatially nonuniform. Such nonuniformity can be modeled by creating an array of inductors based on the field distribution in both the width and the thickness directions. The circuit model is implemented in the advanced design system (ADS) and is capable of predicting the small signal S-parameters, large signal insertion loss, power threshold, time delay, intermodulation (IM) spectrum, and frequency selectivity for CPW-FSLs. The model may also be used for modeling other RF magnetic devices based on similar physics. © 2023 The Authors.","Coplanar waveguide (CPW); equivalent circuit; ferromagnetic resonance (FMR); frequency selective limiter (FSL); magnetic materials; spin wave; yttrium iron garnet (YIG)","Circuit simulation; Coplanar waveguides; Delay circuits; Electric inductors; Ferromagnetic materials; Ferromagnetic resonance; Insertion losses; Magnetic circuits; Magnetic devices; Magnetic fields; Microwave circuits; Spin waves; Timing circuits; Yttrium iron garnet; Coplanar waveguide; Ferromagnetic resonance; Frequency selective limiter; Frequency-selective; Inductor; Integrated circuit modeling; Magnetic-field; Radiofrequencies; Yttrium iron garnet; Yttrium iron garnets; Equivalent circuits","","","","","Defense Advanced Research Projects Agency, DARPA, (W911NF-17- 1-0100); Defense Advanced Research Projects Agency, DARPA","This work was supported by the Defense Advanced Research Projects Agency (DARPA) under Award W911NF-17- 1-0100. This article is an expanded version from the 2023 IEEE Radio and Wireless Symposium (RWS), Las Vegas, NV, USA, 22 25 January 2023 [DOI: 10.1109/RWS55624.2023.10046293].","Adam J.D., Davis L.E., Dionne G.F., Schloemann E.F., Stitzer S.N., Ferrite devices and materials, Ieee Trans. Microw. Theory Techn., 50, 3, pp. 721-737, (2002); Emtage P.R., Stitzer S.N., Interaction of signals in ferromagnetic microwave limiters, Ieee Trans. Microw. Theory Techn., MTT-25, 3, pp. 210-213, (1977); Gillette S.M., Geiler M., Adam J.D., Geiler A.L., Ferrite-based reflective-Type frequency selective limiters, Proc. Ieee MTT-S Int. Microw. Workshop Ser. Adv. Mater. Processes Rf THz Appl. (IMWSAMP), pp. 1-3, (2018); Brown J., Ferromagnetic limiters, Microw. J., 4, pp. 74-79, (1961); Stitzer S., Frequency selective microwave power limiting in thin YIG films, Ieee Trans. Magn., MAG-19, 5, pp. 1874-1876, (1983); Adam J.D., Stitzer S.N., Frequency selective limiters for high dynamic range microwave receivers, Ieee Trans. Microw. Theory Techn., 41, 12, pp. 2227-2231, (1993); Yang S.-S., Kim T.-Y., Kong D.-K., Kim S.-S., Yeom K.-W., A novel analysis of a Ku-band planar p-i-n diode limiter, Ieee Trans. Microw. Theory Techn., 57, 6, pp. 1447-1460, (2009); Ozgur U., Alivov Y., Morkoc H., Microwave ferrites, Part 1: Fundamental properties, J. Mater. Sci., Mater. Electron., 20, 9, pp. 789-834, (2009); Gilbert T.L., The phenomenological theory of damping in ferromagnetic materials, Ieee Trans. Mag., 40, 6, pp. 3443-3449, (2004); Morgenthaler F.R., Survey of ferromagnetic resonance in small ferrimagnetic ellipsoids, J. Appl. Phys., 31, 5, pp. S95-S97, (1960); Orth R., Frequency-selective limiters and their application, Ieee Trans. Electromagn. Compat., EMC-10, 2, pp. 273-283, (1968); Stancil D.D., Prabhakar A., Spin Waves: Theory and Applications., (2009); Cheng M., Patton C.E., Spin wave instability processes in ferrites, Nonlinear Phenomena and Chaos in Magnetic Materials, (1992); Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proc. Ire, 44, 10, pp. 1270-1284, (1956); Schlomann E., Green J.J., Milano U., Recent developments in ferromagnetic resonance at high power levels, J. Appl. Phys., 31, 5, pp. S386-S395, (1960); Simons R.N., Coplanar Waveguide Circuits, Components, and Systems., (2004); Lu L., Song Y.-Y., Bevivino J., Wu M., Planar millimeter wave band-stop filters based on the excitation of confined magnetostatic waves in barium hexagonal ferrite thin film strips, Appl. Phys. Lett., 98, 21, (2011); Gao Q., Fordham M.E., Gu W., Cui H., Wang Y.E., Design RF magnetic devices with linear and nonlinear equivalent circuit models: Demystify RF magnetics with equivalent circuit models, Ieee Microw. Mag., 23, 11, pp. 28-47, (2022); Cui H., Yao Z., Wang Y.E., Coupling electromagnetic waves to spin waves: A physics-based nonlinear circuit model for frequencyselective limiters, Ieee Trans. Microw. Theory Techn., 67, 8, pp. 3221-3229, (2019); Gao Q., Wang Y.E., A compact circuit model for frequencyselective limiters with strong field nonuniformity, Proc. Ieee Radio Wireless Symp. (RWS), pp. 73-75, (2023); Pozar D.M., Microwave Engineering, 3rd Ed., (2005); Corporation A., Electronics Desktop, (2017); Stitzer S.N., Injection locked oscillator theory for frequency selective limiters, Ieee MTT-S Int. Microw. Symp. Dig., pp. 665-668, (2019)","Y.E. Wang; University of California at Los Angeles, Electrical and Computer Engineering Department, Los Angeles, 90095, United States; email: ywang@ee.ucla.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189480","","IETMA","","English","IEEE Trans. Microwave Theory Tech.","Article","Final","","Scopus","2-s2.0-85163427056" +"Ito Y.; Yasuda T.; Kishimoto S.; Nakagawa K.; Ohnuki S.","Ito, Yuta (58943275700); Yasuda, Takumi (58943773900); Kishimoto, Seiya (36188157500); Nakagawa, Katsuji (7403510724); Ohnuki, Shinichiro (7006605105)","58943275700; 58943773900; 36188157500; 7403510724; 7006605105","Multiscale Modeling of 3-D Electromagnetic Fields With Magnetization Dynamics","2024","IEEE Access","12","","","38664","38671","7","0","10.1109/ACCESS.2024.3375927","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85187980979&doi=10.1109%2fACCESS.2024.3375927&partnerID=40&md5=41e5cbf9ec32afd4c524b41ce1004165","Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan","Ito Y., Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan; Yasuda T., Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan; Kishimoto S., Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan; Nakagawa K., Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan; Ohnuki S., Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan","Multiphysics simulation of Maxwell's and Landau-Lifshitz-Gilbert equations are performed to solve electromagnetic fields by considering the dynamics of magnetization. These equations are discretized, and the time-domain responses are computed using a finite-difference time-domain scheme. This study focuses on the acceleration of multiphysics simulations in terms of the multiscale modeling of the interaction between electromagnetic fields and magnetization. A nanoscale magnetic film is conducted to develop a method for measuring the magnetic properties using the near field of the magnetic film. © 2013 IEEE.","Finite-difference time-domain (FDTD) scheme; Landau-Lifshitz-Gilbert (LLG) equation; multiphysics simulation; multiscale modeling","Finite difference time domain method; Magnetic fields; Magnetization; Maxwell equations; Nanomagnetics; Three dimensional displays; Finite-difference methods; Finite-Difference Time-Domain schemes; Landau-Lifshitz-Gilbert equations; Magnetic-field; Magnetization dynamics; Multiphysics simulations; Multiscale modeling; Three-dimensional display; Time domain response; Time-domain analysis; Electromagnetic fields","","","","","","","Kanazawa N., Goto T., Sekiguchi K., Granovsky A.B., Ross C.A., Takagi H., Nakamura Y., Uchida H., Inoue M., The role of Snell's law for a magnonic majority gate, Sci. Rep., 7, 1, pp. 1-8, (2017); Ohkochi T., Fujiwara H., Kotsugi M., Takahashi H., Adam R., Sekiyama A., Nakamura T., Tsukamoto A., Schneider C.M., Kuroda H., Arguelles E.F., Sakaue M., Kasai H., Tsunoda M., Suga S., Kinoshita T., Optical control of magnetization dynamics in Gd-Fe-Co films with different compositions, Appl. Phys. Exp., 10, 10, (2017); Harris V.G., Modern microwave ferrites, IEEE Trans. Magn., 48, 3, pp. 1075-1104, (2012); Slavin A., Tiberkevich V., Nonlinear auto-oscillator theory of microwave generation by spin-polarized current, IEEE Trans. Magn., 45, 4, pp. 1875-1918, (2009); Khitun A., Bao M., Wang K.L., Spin wave magnetic NanoFabric: A new approach to spin-based logic circuitry, IEEE Trans. Magn., 44, 9, pp. 2141-2152, (2008); Cui H., Yao Z., Wang Y.E., Coupling electromagnetic waves to spin waves: A physics-based nonlinear circuit model for frequencyselective limiters, IEEE Trans. Microw. Theory Techn., 67, 8, pp. 3221-3229, (2019); Li J., Wilson C.B., Cheng R., Lohmann M., Kavand M., Yuan W., Aldosary M., Agladze N., Wei P., Sherwin M.S., Shi J., Spin current from sub-terahertz-generated antiferromagnetic magnons, Nature, 578, 7793, pp. 70-74, (2020); Khymyn R., Lisenkov I., Tiberkevich V., Ivanov B.A., Slavin A., Antiferromagnetic THz-frequency josephson-like oscillator driven by spin current, Sci. Rep., 7, 1, (2017); Taflove A., Hagnes S.C., Computational Electrodynamics the Finite-Difference Time-Domain Method, (2005); Nakazawa T., Wu D., Kishimoto S., Shibayama J., Yamauchi J., Ohnuki S., Error-controllable scheme for the LOD-FDTD method, IEEE J. Multiscale Multiphys. Comput. Techn., 7, pp. 135-141, (2022); Wu D., Kishimoto S., Ohnuki S., Optimal parallel algorithm of fast inverse Laplace transform for electromagnetic analysis, IEEE Antennas Wireless Propag. Lett., 19, pp. 2018-2022, (2020); Ohnuki S., Ohnishi R., Wu D., Yamaguchi T., Time-division parallel FDTD algorithm, IEEE Photon. Technol. Lett., 30, 24, pp. 2143-2146, (2018); Kunz K.S., Luebbers R.J., The Finite Difference Time Domain Method for Electromagnetics, pp. 308-322, (1993); Smith D.R., Schurig D., Electromagnetic wave propagation in media with indefinite permittivity and permeability tensors, Phys. Rev. Lett., 90, 7, (2003); Pereda J.A., Vielva L.A., Vegas A., Prieto A., An extended FDTD method for the treatment of partially magnetized ferrites, IEEE Trans. Magn., 31, 3, pp. 1666-1669, (1995); Pereda J.A., Vielva L.A., Solano M.A., Vegas A., Prieto A., FDTD analysis of magnetized ferrites: Application to the calculation of dispersion characteristics of ferrite-loaded waveguides, IEEE Trans. Microw. Theory Techn., 43, 2, pp. 350-357, (1995); Yao Z., Tok R.U., Itoh T., Wang Y.E., A multiscale unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics, IEEE Trans. Microw. Theory Techn., 66, 6, pp. 2683-2696, (2018); Aziz M.M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, Prog. Electromagn. Res. B, 15, pp. 1-29, (2009); Aziz M.M., McKeever C., Wide-band electromagnetic wave propagation and resonance in long cobalt nanoprisms, Phys. Rev. Appl., 13, 3, (2020); Slodika M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Appl. Numer. Math., 46, 1, pp. 95-111, (2003); Yu H., D'Allivy Kelly O., Cros V., Bernard R., Bortolotti P., Anane A., Brandl F., Huber R., Stasinopoulos I., Grundler D., Magnetic thin-film insulator with ultra-low spin wave damping for coherent nanomagnonics, Sci. Rep., 4, 1, (2014); Brown W.F., Micromagnetics, (1978); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, J. Comput. Appl. Math., 176, 2, pp. 263-281, (2005); Nussbaumer H.J., Fast Fourier Transform and Convolution Algorithms, pp. 80-111, (1981)","S. Ohnuki; Nihon University, College of Science and Technology, Tokyo, 102-8275, Japan; email: ohnuki.shinichiro@nihon-u.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","21693536","","","","English","IEEE Access","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85187980979" +"Tonini D.; Wu K.; Saha R.; Wang J.-P.","Tonini, Denis (57412731300); Wu, Kai (56095374500); Saha, Renata (57208154558); Wang, Jian-Ping (35782368600)","57412731300; 56095374500; 57208154558; 35782368600","Magnetic field detection using spin-torque nano-oscillator combined with magnetic flux concentrator","2023","AIP Advances","13","3","035228","","","","1","10.1063/9.0000597","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85150602690&doi=10.1063%2f9.0000597&partnerID=40&md5=cc4de68935c1e159f637850842460425","Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States","Tonini D., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Wu K., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States, Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, 79409, TX, United States; Saha R., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Wang J.-P., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States","Spin-torque nano-oscillators (STNO) are studied in terms of the Landau-Lifshitz-Gilbert (LLG) equation. The effect on the limit of detectivity of an STNO concerning externally applied magnetic fields is studied with micromagnetic models by placing adjacent magnetic flux concentrators (MFCs) at different distances from the nanopillar to analyze the effect on the induced auto-oscillations and magnetization dynamics. Perpendicular STNO structures allow for different detectivities with respect to externally applied magnetic fields depending on the distance from the MFCs to the nanopillar. The optimal design of an STNO combined with MFCs is proposed to improve the limit of detectivity, where the STNO consists of two out-of-plane (OP) ferromagnetic (FM) layers separated by a MgO insulating nonmagnetic (NM) thin film, and the MFCs positioned in the vicinity of the STNO are made of permalloy. The time evolution of the free-layer magnetization is governed by the Landau-Lifshitz-Gilbert (LLG) equation. The auto-oscillations induced within the free-layer averaged magnetization are provoked by externally applied magnetic fields. In addition, the DC current-driven auto-oscillations in the STNO structure are studied as a function of the externally applied magnetic field strength, with and without MFCs. The suppression of the DC current-driven auto-oscillations is observed due to the damping effect generated by the MFCs positioned at varying distances with respect to the STNO. By placing MFCs adjacent to the STNO, the lowest detectable magnetic field strength is enhanced from 10 (μT) to 10 (nT). Therefore, it is concluded that MFCs improve the sensitivity of STNO to externally applied magnetic fields thanks to the damped magnetization dynamics. The results presented in this work could inspire the optimal design of STNO and MFC-based ultra-low magnetic field sensors based on nanoscale oscillators and spintronic diodes. © 2023 Author(s).","","Concentration (process); Iron alloys; Magnesia; Magnetic fields; Magnetic flux; Nanomagnetics; Nickel alloys; Nickel oxide; Optimal systems; Structural design; Applied magnetic fields; Auto-oscillations; Detectivity; Landau-Lifshitz-Gilbert equations; Magnetic flux concentrators; Magnetization dynamics; Nano-oscillator; NanoPillar; Oscillator structures; Spin torque; Magnetization","","","","","Minnesota Partnership for Biotechnology and Medical Genomics, (ML2020)","This study was financially supported by the Minnesota Partnership for Biotechnology and Medical Genomics under Award Number ML2020. Chap 64. Art I, Section . The authors acknowledge the Robert F. Hartmann Chair Professorship, MN Drive Neuromodulation Fellowship, and Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported in this publication. ","Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., AIP Adv., 4, (2014); Chen L., Chen Y., Zhou K., Li H., Pu Y., Xu Y., Du Y., Liu R., Nanoscale, 13, (2021); Tarequzzaman M., Bohnert T., Decker M., Costa J.D., Borme J., Lacoste B., Paz E., Jenkins A.S., Serrano-Guisan S., Back C.H., Ferreira R., Freitas P.P., Commun. Phys., 2, (2019); Park M.G.A., Baek -H. S C., Park B.-G., Lee S.-H., Appl. Phys. Lett., 108, (2016); Zheng C., Chen H.-H., Zhang X., Zhang Z., Liu Y., Chin. Phys. B, 28, (2019); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Cyrille M.-C., Redon O., Dieny B., Nat. 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Eng., 1, (2021); Romera M., Talatchian P., Tsunegi S., Abreu Araujo F., Cros V., Bortolotti P., Trastoy J., Yakushiji K., Fukushima A., Kubota H., Yuasa S., Ernoult M., Vodenicarevic D., Hirtzlin T., Locatelli N., Querlioz D., Grollier J., Nature, 563, (2018); Li C., Wang S., Xu N., Yang X., Liu B., Yang B., Fang L., J. Magn. Magn. Mater., 498, (2020); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature, 425, (2003)","J.-P. Wang; Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, United States; email: jpwang@umn.edu","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85150602690" +"Perumal S.; Sivapragasam J.; Lakshmanan M.","Perumal, Sathishkumar (59454794800); Sivapragasam, J. (35071855700); Lakshmanan, M. (7006704351)","59454794800; 35071855700; 7006704351","Electromagnetic breathing dromion-like structures in an anisotropic ferromagnetic medium","2024","Journal of Magnetism and Magnetic Materials","603","","172266","","","","0","10.1016/j.jmmm.2024.172266","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85196662116&doi=10.1016%2fj.jmmm.2024.172266&partnerID=40&md5=4783e2a4a76cbd4279fc5f41bfdb2331","Department of Physics, Sri Paramakalyani College, Tamil Nadu, Alwarkurichi, 627 412, Tenkasi District, India; Department of Physics, K.S.R. College of Engineering, Tamil Nadu, Tiruchengode, 637 215, India; Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tamil Nadu, Tiruchirapalli, 620 024, India","Perumal S., Department of Physics, Sri Paramakalyani College, Tamil Nadu, Alwarkurichi, 627 412, Tenkasi District, India; Sivapragasam J., Department of Physics, Sri Paramakalyani College, Tamil Nadu, Alwarkurichi, 627 412, Tenkasi District, India, Department of Physics, K.S.R. College of Engineering, Tamil Nadu, Tiruchengode, 637 215, India; Lakshmanan M., Department of Nonlinear Dynamics, School of Physics, Bharathidasan University, Tamil Nadu, Tiruchirapalli, 620 024, India","The influence of Gilbert damping on the propagation of electromagnetic waves (EMWs) in an anisotropic ferromagnetic medium is investigated theoretically. The interaction of the magnetic field component of the electromagnetic wave with the magnetization of a ferromagnetic medium has been studied by solving the associated Maxwell's equations coupled with the Landau–Lifshitz–Gilbert (LLG) equation. When small perturbations are made on the magnetization of the ferromagnetic medium and magnetic field along the direction of propagation of electromagnetic wave by using the reductive perturbation method, the associated nonlinear dynamics is governed by a time-dependent damped derivative nonlinear Schrödinger (TDDNLS) equation. The Lagrangian density function is constructed by using the variational method to solve the TDDNLS equation to understand the dynamics of the system under consideration. The propagation of EMW in a ferromagnetic medium with inherent Gilbert damping admits very interesting nonlinear dynamical structures. These structures include Gilbert damping-managing symmetrically breathing solitons, localized erupting electromagnetic breathing dromion-like modes of excitations, breathing dromion-like soliton, decaying dromion-like modes and an unexpected creation-annihilation mode of excitations in the form of growing-decaying dromion-like modes. © 2024 Elsevier B.V.","Breathing dromion-like soliton; Breathing soliton; Landau–Lifshitz–Gilbert equation; Nonlinear Schrödinger equation; The variational method","Anisotropy; Circular waveguides; Damping; Electromagnetic waves; Ferromagnetic materials; Ferromagnetism; Magnetic fields; Magnetization; Nonlinear equations; Ordinary differential equations; Perturbation techniques; Solitons; Breathing dromion-like soliton; Breathing solitons; Dromions; Ferromagnetics; Gilbert damping; Landau-Lifshitz-Gilbert equations; Nonlinear schrödinge equation; Propagation of electromagnetic waves; The variational method; Maxwell equations","","","","","Science and Engineering Research Board, SERB; Department of Science and Technology, Ministry of Science and Technology, India, DST, (NSC/2020/00029); Department of Science and Technology, Ministry of Science and Technology, India, DST","The author M. Lakshmanan wishes to thank the Science and Engineering Research Board, Department of Science and Technology, Government of India for the award of a National Science Chair position under Grant No. NSC/2020/00029.","Fleischer J.W., Segev M., Efremidis N.K., Christodoulides D.N., Observation of two-dimensional discrete solitons in optically induced nonlinear photonic lattices, Nature, 422, (2003); Fert A., Reyren N., Cros V., Magnetic skyrmions: Advances in physics and potential applications, Nat. Rev. Mater., 2, (2017); Stanciu C.D., Hansteen F., Kimel A.V., Kirilyuk A., Tsukamoto A., Itoh A., Rasing T., All-optical magnetic recording with circularly polarized light, Phys. Rev. Lett., 99, (2007); Chien C.L., Gornakov V.S., Nikitenko V.I., Shapiro A.J., Shull R.D., Hybrid domain walls and antiferromagnetic domains in exchange-coupled ferromagnet/antiferromagnet bilayers, Phys. Rev. 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B, 77, (2008); Logoboy N.A., Sonin E.B., Two-dimensional domain-wall magnon waves in superconducting ferromagnets, Phys. Rev. B, 75, (2007); Kavitha L., Saravanan M., Srividya S., Gopi D., Breatherlike electromagnetic wave propagation in an antiferromagnetic medium with Dzyaloshinsky-Moriya interaction, Phys. Rev. E, 84, (2011); Leblond H., Manna M., Benjamin-feir-type instability in a saturated ferrite: Transition between focusing and defocusing regimes for polarized electromagnetic waves, Phys. Rev. E, 50, (1994); MacKay R.S., Sepulchre J.A., Stability of discrete breathers, Phys. D Nonl. Phen., 119, (1998); Lakshmanan M., Saxena A., Dynamic and static excitations of a classical discrete anisotropic Heisenberg ferromagnetic spin chain, Phys. D Nonl. Phen., 237, (2008); Lakshmanan M., Subash B., Saxena A., Intrinsic localized modes of a classical discrete anisotropic Heisenberg ferromagnetic spin chain, Phys. Lett. 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Lett., 102, (2009); Barla P., Joshi V.K., Bhat S., Spintronic devices: A promising alternative to cmos devices, J. Comp. Elec., 20, (2021); Taniuti T., Yajima N., Perturbation method for a nonlinear wave modulation I, J. Math. Phys., 10, (1969); Kaup D.J., Newell A.C., An exact solution for a derivative nonlinear Schrödinger equation, J. Math. Phys., 19, (1978); Liu S.L., Wang W.Z., Exact n-soliton solution of the modified nonlinear Schrödinger equation, Phys. Rev. E, 48, (1993); Anderson D., Lisak M., Nonlinear asymmetric self-phase modulation and self-steepening of pulses in long optical waveguides, Phys. Rev. A, 27, (1983); Rogister A., Parallel propagation of nonlinear low-frequency waves in high-β plasma, Phys. Fluids, 14, (1971); Mertens F.G., Quintero N.R., Bishop A.R., Nonlinear Schrödinger equation with spatiotemporal perturbations, Phys. Rev. E, 81, (2010); Lakshmanan M., Daniel M., Soliton damping and energy loss in the classical continuum Heisenberg spin chain, Phys. Rev. B, 24, (1981)","S. Perumal; Department of Physics, Sri Paramakalyani College, Alwarkurichi, Tamil Nadu, 627 412, Tenkasi District, India; email: perumal_sathish@yahoo.co.in","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85196662116" +"Chen L.; Li Y.; Ben T.; Zhang Z.; Jing L.","Chen, Long (57190871677); Li, Yuqing (58821741600); Ben, Tong (57188849446); Zhang, Zheyu (58821672600); Jing, Libing (55508087200)","57190871677; 58821741600; 57188849446; 58821672600; 55508087200","Research on the simulation accuracy of static hysteresis loops of electrical steels using an improved simplified LLG equation","2024","AIP Advances","14","1","015225","","","","0","10.1063/9.0000743","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85182728756&doi=10.1063%2f9.0000743&partnerID=40&md5=f9de912e9e7d308e9589334cfe8ed188","College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; Hubei Provincial Research Center on Microgrid Engineering Technology, China Three Gorges University, Yichang, China","Chen L., College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; Li Y., College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; Ben T., College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; Zhang Z., College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; Jing L., College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China, Hubei Provincial Research Center on Microgrid Engineering Technology, China Three Gorges University, Yichang, China","For tackling the problem of large errors in simulating the static inner symmetrical minor hysteresis loops through the Simplified Landau-Lifshitz-Gilbert (S-LLG) equation, a modification by improving the grain structure arrangement and introducing additional hysteresis energy function is proposed. With the proposed model, only a unified set of parameters identified by four static hysteresis loops is needed to predict hysteresis loops under arbitrarily different magnetic flux density levels. To verify the global simulation capability of the proposed model, the simulation results of hysteresis loops are compared with the measured data of a grain-oriented (GO) steel. The obtained results show that the model has good simulation ability for hysteresis loops under different magnetic flux densities for both sinusoidal and harmonic excitation conditions. © 2024 Author(s).","","Hysteresis; Magnetic flux; Magnetic materials; Silicon steel; Density levels; Electrical steels; Energy functions; Global simulation; Hysteresis energies; Landau-Lifshitz-Gilbert equations; LLG equation; Minor hysteresis loop; Simulation accuracy; Static hysteresis loops; Hysteresis loops","","","","","National Natural Science Foundation of China, NSFC, (52007102, 52207012)","This work was partly supported by the National Natural Science Foundation of China under Grant No. 52007102 and No. 52207012. The authors would like to thank Prof. Yoshiki HANE for the simplified micromagnetic model and help. ","Krings A., Boglietti A., Cavagnino A., Sprague S., IEEE Trans. Ind. Electron., 64, (2017); Jiles D.C., Atherton D.L., Journal of Magnetism and Magnetic Materials, 61, (1986); Hussain S., Lowther D.A., IEEE Trans. Magn., 53, (2017); Mayergoyz I., IEEE Trans. Magn., 22, (1986); Zeinali R., Krop D.C.J., Lomonova E.A., IEEE Trans. Magn., 56, (2020); Li Y., Zhu J., Li Y., Zhu L., Journal of Magnetism and Magnetic Materials, 544, (2022); Furuya A., Fujisaki J., Uehara Y., Et al., IEEE Trans. Magn., 50, (2014); Tanaka H., Nakamura K., Ichinokura O., J. Magn. Soc. Jpn., 39, (2015); Hane Y., Nakamura K., Ohinata T., Et al., IEEE Trans. Magn., 55, (2019); Tanaka H., Nakamura K., Ichinokura O., J. Phys., Conf. Ser., 903, (2017); Chen L., Zhang Z., Tong B., Et al., AIP Adv., 12, (2022); Chen L., Yi Q., Tong B., Et al., AIP Adv., 11, (2021)","T. Ben; College of Electrical Engineering and New Energy, China Three Gorges University, Yichang, China; email: bentong@ctgu.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85182728756" +"XianYu Z.-N.; Cheng T.-M.; Chi X.-D.; Du A.","XianYu, Zheng-Nan (57512345000); Cheng, Tai-Min (9333087100); Chi, Xiao-Dan (56797591900); Du, An (7006264005)","57512345000; 9333087100; 56797591900; 7006264005","Switching of magnetic bilayer nanotube ring with antiferromagnetically coupled layers in an annular field","2024","Journal of Magnetism and Magnetic Materials","594","","171912","","","","0","10.1016/j.jmmm.2024.171912","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85186511176&doi=10.1016%2fj.jmmm.2024.171912&partnerID=40&md5=8617cf3f16cd97e01391ade4d3528083","Department of physics, College of Sciences, Shenyang University of Chemical Technology, Shenyang, 110142, China; Department of Basic, Dalian Naval Academy, Dalian, 116018, China; Department of physics, College of Sciences, Northeastern University, Shenyang, 110819, China","XianYu Z.-N., Department of physics, College of Sciences, Shenyang University of Chemical Technology, Shenyang, 110142, China; Cheng T.-M., Department of physics, College of Sciences, Shenyang University of Chemical Technology, Shenyang, 110142, China; Chi X.-D., Department of Basic, Dalian Naval Academy, Dalian, 116018, China; Du A., Department of physics, College of Sciences, Northeastern University, Shenyang, 110819, China","The magnetization switching behavior of magnetic nanotube rings with core–shell structure is investigated by solving the Landau-Lifshitz-Gilbert (LLG) equation, focusing on the effects of the magnetic structure, interfacial exchange interactions, anisotropy constants, and transverse field on the coercivity of the system. The reduction of the coercivity of the magnetic nanorings can increase the magnetization switching rate and reduces the energy consumption when the magnetic nanorings are used as magnetic storage units. In the study, it is found that the antiferromagnetic exchange interaction between the spins in the core can greatly reduce the coercivity of the system, and the coercivity decreases with the increase of the interface exchange interaction. When the anisotropy constant of the antiferromagnetic core gradually increases, the coercivity of the system varies nonlinearly and a point of minima occurs. Finally, the effect of the transverse magnetic field on the hysteresis behavior of the system is also discussed, and it is found that the coercivity of the system decreases gradually with the increase of the transverse magnetic field, but the hysteresis loop of the system is distorted when the critical value is exceeded. © 2024 Elsevier B.V.","Antiferromagnetic; Core–shell structure; Hysteresis behavior; Landau-Lifshitz-Gilbert equation; Nanotube ring","Anisotropy; Antiferromagnetism; Coercive force; Energy utilization; Exchange interactions; Hysteresis; Magnetic materials; Magnetic storage; Magnetization; Nanorings; Nanostructured materials; Anisotropy constants; Antiferro-magnetically coupled; Antiferromagnetics; Core shell structure; Hysteresis behavior; Landau-Lifshitz-Gilbert equations; Magnetic bilayer; Magnetization switching; Nanotube ring; Transverse magnetic field; Nanotubes","","","","","Department of Education of Liaoning Province, (LQ2020014); Department of Education of Liaoning Province","This project was supported by the Liaoning Provincial Department of Education Youth Nursery Project ( LQ2020014 )","Liu Z., Yang B., Cao W.W., Fohtung E., Lookman T., Phys. Rev. A, 8, (2017); Salinas H.D., Restrepo J., Iglesias O., Phys. Rev. B, 101, (2020); Zhu J.G., Zheng Y.F., J. Appl. Phys., 87, pp. 6668-6673, (2000); Shi J., Zhu T., Durlam M., Chem E., Tehrani S., IEEE Trans. Magn., 34, pp. 997-999, (1998); Cowburn R.P., J. Phys. d: Appl. Phys., 33, pp. R1-R16, (2000); Dunin-Borkowski R.E., Mccartney M.R., Kardynal B., Parkin S.S.P., Scheinfein M.R., Smith D.J., J. Microse, 200, pp. 187-205, (2000); Vaz C.A.F., Lopez-Diaz L., Klaui M., Bland J.A.C., Monchesky T.L., Unguris J., Cui Z., Phys. Rev. B, 67, (2003); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. Lett., 83, (1999); Li S.P., Peyrade D., Natali M., Lebib A., Chen Y., Ebels U., Buda L.D., Ounadjela K., Phys. Rev. Lett., 86, (2001); Gabriel D., Chaves-O'Flynn A.D., Kent D.L.S., Phys. Rev. B, 79, (2009); Pradhan N.R., Licht A.S., Li Y., Sun Y., Tuominen M.T., Aidala K.E., Nanotechnology, 22, (2011); Zhang W., Haas S., Phys. Rev. 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Magn., 31, pp. 483-492, (2018); Xianyu Z.N., Du A., J. Magn. Magn. Mater., 485, (2019); Liu J., Dai H., Hafner J.H., Colbert D.T., Tans S.J., Dekker C., Smalley R.E., Nature (london), 385, (1997); Wang W.D., Laird E.D., Gogotsi Y., Li C.Y., Carbon, 50, (2012); Han J., Chem. Phys. Lett., 282, (1998); Shea H.R., Martel R., Avouris P.H., Phys. Rev. Lett., 84, (2000); Xianyu Z.N., Du A., Phys. Status Solidi B, 254, (2017); Xianyu Z.N., Du A., J. Appl. Phys., 124, (2018); Campos C.L.A.V., J. Magn. Magn. Mater., 508, (2020); He L., Chen C.P., Et al., Phys. Rev. B, 75, (2007); Deviren B., Keskin M., Phys. Lett. A, 376, pp. 1011-1019, (2012); Kaneyoshi T., J. Magn. Magn. Mater., 323, pp. 1145-1151, (2011); Ma Y., Du A., J. Magn. Magn. Mater., 321, (2009); Chubykalo-Fesenko O., Nowak U., Chantrell R.W., Garanin D., Phys. Rev. B, 74, (2006); Bruno P., Physical origins and theoretical models of magnetic anisotropy, in ferienkurse des forschungszentrums Jülich, (1993); Skomski R., Simple models of magnetism, (2008); He K., Smith D.J., McCartney M.R., J. Appl. Phys., 107, 9, (2010)","Z.-N. XianYu; Department of physics, College of Sciences, Shenyang University of Chemical Technology, Shenyang, 110142, China; email: xianyuzhengnan@163.com","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85186511176" +"Pruckner B.; Jørstad N.P.; Bendra M.; Hadámek T.; Goes W.; Selberherr S.; Sverdlov V.","Pruckner, Bernhard (58489551500); Jørstad, Nils Petter (57660717900); Bendra, Mario (57320954500); Hadámek, Tomáš (57321034300); Goes, Wolfgang (55884148500); Selberherr, Siegfried (8840302400); Sverdlov, Viktor (8908640600)","58489551500; 57660717900; 57320954500; 57321034300; 55884148500; 8840302400; 8908640600","Simulation of Advanced MRAM Devices for sub-ns Switching","2024","International Conference on Simulation of Semiconductor Processes and Devices, SISPAD","","","","","","","0","10.1109/SISPAD62626.2024.10733317","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85210102600&doi=10.1109%2fSISPAD62626.2024.10733317&partnerID=40&md5=69692936c445c80d4e1c3dce398509b3","Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria; Institute for Microelectronics, Tu Wien, Gußhausstraße 27-29, Wien, A-1040, Austria; Silvaco Europe Ltd., Compass Point, Cambridge, St Ives, PE27 5JL, United Kingdom","Pruckner B., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria; Jørstad N.P., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria; Bendra M., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria, Institute for Microelectronics, Tu Wien, Gußhausstraße 27-29, Wien, A-1040, Austria; Hadámek T., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria; Goes W., Silvaco Europe Ltd., Compass Point, Cambridge, St Ives, PE27 5JL, United Kingdom; Selberherr S., Institute for Microelectronics, Tu Wien, Gußhausstraße 27-29, Wien, A-1040, Austria; Sverdlov V., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria, Institute for Microelectronics, Tu Wien, Gußhausstraße 27-29, Wien, A-1040, Austria","This work explores pathways to achieve reliable sub-ns switching for Spin-Transfer Torque (STT) and Spin- Orbit Torque (SOT) MRAM devices by employing a coupled spin and charge drift-diffusion and micromagnetics simulation framework utilizing the Landau-Lifshitz-Gilbert (LLG) equation. We consider several vital mechanisms of spin current generation, such as spin current polarization in ferromagnets (FMs), the spin Hall effect (SHE) in heavy metals (HMs), the Rashba-Edelstein effect (REE) at HM/FM interfaces, the magnetic SHE (MSHE) in noncollinear anti-ferromagnets (NC-AFMs), and the anomalous Hall effect (AHE) in FMs. We employ boundary conditions based on quantum mechanical scattering from a magnetic exchange and Rashba SOC potential at the HM/FM interfaces. We also account for all critical effects in the LLG equation, such as the interfacial Dzyaloshinskii-Moriya interaction (DMI), the demag-netizing field, perpendicular magnetic anisotropy, and interlayer exchange coupling (IEC). © 2024 IEEE.","SOT-MRAM; Spintronics; STT-MRAM; sub- ns switching","Diluted magnetic semiconductors; Electromagnetic induction; Ferromagnetism; Hall effect devices; Magnetic anisotropy; Magnetic bubble memories; Magnetic logic devices; Quantum Hall effect; Spin dynamics; Spin Hall effect; Spin orbit coupling; Spin polarization; Spintronics; Coupled spins; Ferromagnets; Landau-Lifshitz-Gilbert equations; Ns switching; Spin currents; Spin orbits; Spin transfer torque; Spin- orbit torque-MRAM; Spin-transfer torque-MRAM; Sub- ns switching; MRAM devices","","","","","","","Lee T.Y., Et al., IEDM, pp. 1071-1074, (2022); Saha R., Et al., J. Magn. Magn. Mater, 551, (2022); Pruckner B., Et al., Physica B: Condensed Matter, 688, (2024); Bendra M., Et al., Micromachines, 15, (2024); Patel S.K., Et al., Spin. Mag. Nano, 8, pp. 201-210, (2023); Hu G., Et al., IEDM, pp. 251-254, (2021); Bendra M., Et al., Devices Research Conference (DRC), (2024); Hu S., Et al., Nat. Commun, 13, (2022); Ryu J., Et al., Nature Electronics, 5, pp. 217-223, (2022); Fiorentini S., Et al., Sci. Rep, 12, (2022); ViennaSpinMag; Amin V.P., Et al., J. Appl. Phys, 128, (2020); Jorstad N., Et al., Physcia B: Condensed Matter, 676, (2024); Amin V.P., Et al., Phys. Rev. B, (2016); Xiao J., Et al., Phys. Rev. B, 72, (2005); Ender J., Et al., 2020 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), pp. 213-216, (2020); Ruderman M.A., Et al., Phys. Rev, 96, pp. 99-102, (1954); Bruno P., Et al., Journal of Physics: Condensed Matter, 11, pp. 9403-9419, (1999); Inomata K., Et al., Phys. Rev. Lett, 74, pp. 1863-1866, (1995); Chshiev M., Et al., Phys. Rev. B, (2015); Zhang S., Et al., Phys. Rev. Lett., (2002); Salemi L., Et al., Phys. Rev. B, 106, (2022)","B. Pruckner; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, Austria; email: pruckner@iue.tuwien.ac.at","","Institute of Electrical and Electronics Engineers Inc.","","2024 International Conference on Simulation of Semiconductor Processes and Devices, SISPAD 2024","25 September 2024 through 27 September 2024","San Jose","203820","19461569","979-833151635-2","","","English","Int Conf Simul Semicond Process Dev Proc SISPAD","Conference paper","Final","","Scopus","2-s2.0-85210102600" +"Bunaiyan S.; Datta S.; Camsari K.Y.","Bunaiyan, Saleh (57219564953); Datta, Supriyo (57206956172); Camsari, Kerem Y. (56682099700)","57219564953; 57206956172; 56682099700","Heisenberg machines with programmable spin circuits","2024","Physical Review Applied","22","1","014014","","","","2","10.1103/PhysRevApplied.22.014014","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85198224110&doi=10.1103%2fPhysRevApplied.22.014014&partnerID=40&md5=7275e0404617eeedb0e5f404105771a6","Electrical Engineering Department, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia; Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, 93106, CA, United States; Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States","Bunaiyan S., Electrical Engineering Department, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran, 31261, Saudi Arabia, Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, 93106, CA, United States; Datta S., Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States; Camsari K.Y., Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, 93106, CA, United States","We show that we can harness two recent experimental developments to build a compact hardware emulator for the classical Heisenberg model in statistical physics. The first is the demonstration of spin-diffusion lengths in excess of microns in graphene even at room temperature. The second is the demonstration of low-barrier magnets (LBMs) whose magnetization can fluctuate rapidly even at subnanosecond rates. Using experimentally benchmarked circuit models, we show that an array of LBMs driven by an external current source has a steady-state distribution corresponding to a classical system with an energy function of the form E=-(1/2)∑i,jJij(m^i⋅m^j). This may seem surprising for a nonequilibrium system, but we show that it can be justified by a Lyapunov function corresponding to a system of coupled Landau-Lifshitz-Gilbert (LLG) equations. The Lyapunov function we construct describes LBMs interacting through the spin currents they inject into the spin-neutral substrate. We suggest ways to tune the coupling coefficient Jij so that it can be used as a hardware solver for optimization problems involving continuous variables represented by vector magnetizations, similar to the role of the Ising model in solving optimization problems with binary variables. Finally, we train a Heisenberg xor gate based on a network of four coupled stochastic LLG equations, illustrating the concept of probabilistic computing with a programmable Heisenberg model. © 2024 American Physical Society. ","","Ising model; Magnetization; Optimization; Statistical Physics; Stochastic models; Stochastic systems; Timing circuits; Classical Heisenberg model; Experimental development; Hardware emulators; Heisenberg; Landau-Lifshitz-Gilbert equations; Lyapunov's functions; Optimization problems; Spin-diffusion length; Statistical physics; Subnanosecond; Lyapunov functions","","","","","ONR-MURI, (N000142312708)","We acknowledge support from ONR-MURI Grant No. N000142312708, OptNet: Optimization with p-Bit Networks. The authors are grateful to Shun Kanai, Saroj Dash, Punyashloka Debashis, and Zhihong Chen for fruitful discussions.","Teh Y. W., Welling M., Osindero S., Hinton G. E., Energy-based models for sparse overcomplete representations, J. Mach. Learn. Res, 4, (2003); Berloff N. G., Silva M., Kalinin K., Askitopoulos A., Topfer J. D., Cilibrizzi P., Langbein W., Lagoudakis P. G., Realizing the classical (Equation presented) Hamiltonian in polariton simulators, Nat. 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(57927749300); Padrón-Hernández, Eduardo (6504643531)","57927749300; 6504643531","Magnetostatic modes in a Purely Conductive Material@Ferromagnetic (Core@Shell) spherical structure","2023","Journal of Magnetism and Magnetic Materials","585","","171123","","","","0","10.1016/j.jmmm.2023.171123","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85167808478&doi=10.1016%2fj.jmmm.2023.171123&partnerID=40&md5=2fa4014cd898b0126556394bc4d231a0","Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil","Saldanha-Bautista D.E., Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil; Padrón-Hernández E., Departamento de Física, Universidade Federal de Pernambuco, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, Recife, 50740-540, Brazil","In the present work we study the dispersion relation of magnetostatic modes in the spherical core@shell structure of purely conductive material (PCM) as core and soft ferromagnetic (FM) as shell. The PCM is a sphere of radius r1 covered by an FM shell of inner radius r1 and outer radius r2. To solve the equation, a transformation of the Walker equation in the FM region based on the solution proposed by Plumier was performed. The obtained solutions are consistent with those obtained by approximate methods proposed in the literature. © 2023 Elsevier B.V.","Ferromagnetic hollow sphere; LLG equation; Magnetostatic modes; PCM@FM structure","Ferromagnetic materials; Ferromagnetism; Frequency modulation; Magnetostatics; Shells (structures); Spheres; Core shell; Ferromagnetic cores; Ferromagnetic hollow sphere; Ferromagnetic structures; Ferromagnetics; Hollow sphere; LLG equation; Magnetostatic modes; Purely conductive material@ferromagnetic structure; Spherical structures; Conductive materials","","","","","Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq; Financiadora de Estudos e Projetos, FINEP; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, FACEPE","The authors are grateful to the Brazilian Agencies: CAPES ; CNPq ; FINEP and FACEPE .","Gans R., Loyarte R., Ann. Phys., 64, pp. 209-249, (1921); Dorfmann J., Einige bemerkungen zur kenntnis des mechanismus magnetischer erscheinungen, Z. Phys., 17, 1, pp. 98-111, (1923); Griffiths J.H., Anomalous high-frequency resistance of ferromagnetic metals, Nature, 158, 4019, pp. 670-671, (1946); Hurben M., Patton C., Theory of magnetostatic waves for in-plane magnetized anisotropic films, J. Magn. Magn. Mater., 163, 1, pp. 39-69, (1996); Landau L., Lifshitz E., 3 - On the theory of the dispersion of magnetic permeability in ferromagnetic bodies Reprinted from Physikalische Zeitschrift der Sowjetunion 8, Part 2, 153, 1935, Perspectives in Theoretical Physics, pp. 51-65, (1992); Holstein T., Primakoff H., Field dependence of the intrinsic domain magnetization of a ferromagnet, Phys. Rev., 58, 12, (1940); Van Vleck J., Ferromagnetic resonance, Physica, 17, 3-4, pp. 234-252, (1951); Phillips T., Rosenberg H., Spin waves in ferromagnets, Rep. Progr. Phys., 29, 1, (1966); Lee S., Grudichak S., Sklenar J., Tsai C., Jang M., Yang Q., Zhang H., Ketterson J.B., Ferromagnetic resonance of a YIG film in the low frequency regime, J. Appl. Phys., 120, 3, (2016); Rachford F.J., Levy M., Osgood R., Kumar A.R., Bakhru H., Magnetization and ferromagnetic resonance studies in implanted and crystal ion sliced bismuth-substituted yttrium iron garnet films, J. Appl. Phys., 85, pp. 5217-5219, (1999); Guo Z., Wu F., Xue C., Jiang H., Sun Y., Li Y., Chen H., Significant enhancement of magneto-optical effect in one-dimensional photonic crystals with a magnetized epsilon-near-zero defect, J. Appl. Phys., 124, 10, (2018); Rezende S.M., Fundamentals of Magnonics, Vol. 969, (2020); White R.L., Solt I.H., Multiple ferromagnetic resonance in ferrite spheres, Phys. Rev., 104, 1, (1956); Walker L.R., Magnetostatic modes in ferromagnetic resonance, Phys. Rev., 105, 2, (1957); Ansalone P., Basso V., Walker's modes in ferromagnetic finite hollow cylinder, Physica B, 578, (2020); Eshbach J., Damon R., Surface magnetostatic modes and surface spin waves, Phys. Rev., 118, 5, (1960); Sakharov V., Khivintsev Y., Stognij A., Vysotskii S., Filimonov Y., Beginin E., Sadovnikov A., Nikitov S., Spin-wave excitations in YIG films grown on corrugated substrates, Journal of Physics: Conference Series, Vol. 1389, (2019); Korber L., Kezsmarki I., Kakay A., Mode splitting of spin waves in magnetic nanotubes with discrete symmetries, (2022); Prat-Camps J., Navau C., Sanchez A., Chen D.-X., Demagnetizing factors for a hollow sphere, IEEE Magn. Lett., 7, pp. 1-4, (2015); Krupka J., Pacewicz A., Salski B., Kopyt P., Bourhill J., Goryachev M., Tobar M., Electrodynamic improvements to the theory of magnetostatic modes in ferrimagnetic spheres and their applications to saturation magnetization measurements, J. Magn. Magn. Mater., 487, (2019); McKeever C., Ogrin F., Aziz M., Microwave magnetization dynamics in ferromagnetic spherical nanoshells, Phys. Rev. B, 100, 5, (2019); Saldanha-Bautista D., Padron-Hernandez E., Magnetostatic modes in a hollow ferromagnetic sphere, Phys. Lett. A, 453, (2022); Plumier R., Magnetostatic modes in a sphere and polarization current corrections, Physica, 28, 4, pp. 423-444, (1962); Dobrovolskiy O.V., Bunyaev S.A., Vovk N.R., Navas D., Gruszecki P., Krawczyk M., Sachser R., Huth M., Chumak A.V., Guslienko K.Y., Et al., Spin-wave spectroscopy of individual ferromagnetic nanodisks, Nanoscale, 12, 41, pp. 21207-21217, (2020); Khan S., Lawler N.B., Bake A., Rahman R., Cortie D., Iyer K.S., Martyniuk M., Kostylev M., Iron oxide-Palladium core-shell nanospheres for ferromagnetic resonance-based hydrogen gas sensing, Int. J. Hydrogen Energy, 47, 12, pp. 8155-8163, (2022); Koltunowicz T.N., Zukowski P., Sidorenko J., Bayev V., Fedotova J.A., Opielak M., Marczuk A., Ferromagnetic resonance spectroscopy of CoFeZr-Al2O3 granular films containing “FeCo core – oxide shell” nanoparticles, J. Magn. Magn. Mater., 421, pp. 98-102, (2017); Bizdoaca E., Spasova M., Farle M., Hilgendorff M., Caruso F., Magnetically directed self-assembly of submicron spheres with a Fe3O4 nanoparticle shell, J. Magn. Magn. Mater., 240, 1, pp. 44-46, (2002); Choopani S., Samavat F., Kolobova E.N., Grishin A.M., Ferromagnetic resonance and magnetic anisotropy in biocompatible Y3Fe5O12@Na0.5K0.5NbO3 core-shell nanofibers, Ceram. Int., 46, 2, pp. 2072-2078, (2020); Wu K., Shin Y., Yang C., Wang G., Horng D., Preparation and characterization of bamboo charcoal/Ni0.5Zn0.5Fe2O4 composite with core-shell structure, Mater. Lett., 60, 21, pp. 2707-2710, (2006)","E. Padrón-Hernández; Departamento de Física, Universidade Federal de Pernambuco, Recife, Av. Jorn. Aníbal Fernandes, s/n - Cidade Universitária, PE, 50740-540, Brazil; email: eduardo.hernandez@ufpe.br","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85167808478" +"Di Fratta G.; Jüngel A.; Praetorius D.; Slastikov V.","Di Fratta, Giovanni (23093879900); Jüngel, Ansgar (7004006942); Praetorius, Dirk (6507452481); Slastikov, Valeriy (6507089375)","23093879900; 7004006942; 6507452481; 6507089375","Spin-diffusion model for micromagnetics in the limit of long times","2023","Journal of Differential Equations","343","","","467","494","27","1","10.1016/j.jde.2022.10.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85140334600&doi=10.1016%2fj.jde.2022.10.012&partnerID=40&md5=d9b7a7021aef6a8ef0e9de86bb5ab0c4","TU Wien, Institute of Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, Wien, 1040, Austria; University of Bristol, School of Mathematics, Bristol, BS8 1UG, United Kingdom","Di Fratta G., TU Wien, Institute of Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, Wien, 1040, Austria; Jüngel A., TU Wien, Institute of Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, Wien, 1040, Austria; Praetorius D., TU Wien, Institute of Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, Wien, 1040, Austria; Slastikov V., University of Bristol, School of Mathematics, Bristol, BS8 1UG, United Kingdom","In this paper, we consider spin-diffusion Landau–Lifshitz–Gilbert equations (SDLLG), which consist of the time-dependent Landau–Lifshitz–Gilbert (LLG) equation coupled with a time-dependent diffusion equation for the electron spin accumulation. The model takes into account the diffusion process of the spin accumulation in the magnetization dynamics of ferromagnetic multilayers. We prove that in the limit of long times, the system reduces to simpler equations in which the LLG equation is coupled to a nonlinear and nonlocal steady-state equation, referred to as SLLG. As a by-product, the existence of global weak solutions to the SLLG equation is obtained. Moreover, we prove weak-strong uniqueness of solutions of SLLG, i.e., all weak solutions coincide with the (unique) strong solution as long as the latter exists in time. The results provide a solid mathematical ground to the qualitative behavior originally predicted by ZHANG, LEVY, and FERT in [44] in ferromagnetic multilayers. © 2022 The Author(s)","Asymptotic analysis; Existence of solutions; Landau–Lifshitz–Gilbert equation; Micromagnetics; Spin diffusion; Weak-strong uniqueness","","","","","","Leverhulme Trust, (P34609, RPG-2018-438); Austrian Science Fund, FWF, (P30000, P33010, SFB F65, W1245); Erwin Schrödinger International Institute for Mathematics and Physics, ESI; Max-Planck-Institut für Mathematik in den Naturwissenschaften, MIS","Funding text 1: G. Di F., A. J., and D. P. acknowledge support from the Austrian Science Fund (FWF) through the special research program Taming complexity in partial differential systems (Grant SFB F65 ). ; Funding text 2: A. J. was partially supported by the FWF , grants W1245 , P30000 , and P33010 . ; Funding text 3: G. Di F. A. J. and D. P. acknowledge support from the Austrian Science Fund (FWF) through the special research program Taming complexity in partial differential systems (Grant SFB F65). A. J. was partially supported by the FWF, grants W1245, P30000, and P33010. V. S. acknowledges support by Leverhulme grant RPG-2018-438. This work was initiated when V. S. enjoyed the hospitality of the Vienna Center for PDEs at TU Wien. G. Di F. was partially supported by the Austrian Science Fund (FWF) through the project Analysis and Modeling of Magnetic Skyrmions (grant P34609). G. Di F. thanks MedUni Wien for support and hospitality. G. Di F. and V. S. would also like to thank the Max Planck Institute for Mathematics in the Sciences in Leipzig for support and hospitality. All authors acknowledge support from ESI, the Erwin Schrödinger International Institute for Mathematics and Physics in Wien, given in occasion of the Workshop on New Trends in the Variational Modeling and Simulation of Liquid Crystals held at ESI, in Wien, on December 2–6, 2019.; Funding text 4: V. S. acknowledges support by Leverhulme grant RPG-2018-438 . This work was initiated when V. S. enjoyed the hospitality of the Vienna Center for PDEs at TU Wien. ; Funding text 5: G. Di F. was partially supported by the Austrian Science Fund (FWF) through the project Analysis and Modeling of Magnetic Skyrmions (grant P34609 ). G. Di F. thanks MedUni Wien for support and hospitality. ","Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suess D., Spin-polarized transport in ferromagnetic multilayers: an unconditionally convergent FEM integrator, Comput. Math. 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Differ. Equ., 260, pp. 6828-6854, (2016); Zhang S., Levy P.M., Fert A., Mechanisms of spin-polarized current-driven magnetization switching, Phys. Rev. Lett., 88, (2002)","G. Di Fratta; TU Wien, Institute of Analysis and Scientific Computing, Wien, Wiedner Hauptstraße 8-10, 1040, Austria; email: giovanni.difratta@asc.tuwien.ac.at","","Academic Press Inc.","","","","","","00220396","","JDEQA","","English","J. Differ. Equ.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85140334600" +"De A.; Lentfert A.; Scheuer L.; Stadtmüller B.; Pirro P.; Freymann G.V.; Aeschlimann M.","De, Anulekha (56673580800); Lentfert, Akira (57222109042); Scheuer, Laura (57200365780); Stadtmüller, Benjamin (36460333000); Pirro, Philipp (6506692794); Freymann, Georg Von (57204734795); Aeschlimann, Martin (7003360078)","56673580800; 57222109042; 57200365780; 36460333000; 6506692794; 57204734795; 7003360078","Spin Dynamics with Inertia in Ferromagnetic Thin Films","2023","2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023 - Proceedings","","","","","","","0","10.1109/INTERMAGShortPapers58606.2023.10228822","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85172737856&doi=10.1109%2fINTERMAGShortPapers58606.2023.10228822&partnerID=40&md5=467648f4f0d9791402ff114dc29edbef","Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany; Institute of Physics, Johannes Gutenberg University Mainz, Mainz, 55128, Germany; Fraunhofer Institute for Industrial Mathematics, Kaiserslautern, 67663, Germany","De A., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany; Lentfert A., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany; Scheuer L., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany; Stadtmüller B., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany, Institute of Physics, Johannes Gutenberg University Mainz, Mainz, 55128, Germany; Pirro P., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany; Freymann G.V., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany, Fraunhofer Institute for Industrial Mathematics, Kaiserslautern, 67663, Germany; Aeschlimann M., Technical University of Kaiserslautern, Department of Physics and Research Center OPTIMAS, Kaiserslautern, 67663, Germany","Understanding spin dynamics on femto- and picosecond timescales offers new opportunities for faster and more efficient devices. On short time scales, the inertia term in the LLG equation becomes important, leading to the nutation of spins. However, experimental observation of nutation is still in its infancy. Here, we experimentally demonstrate a non-resonant excitation of inertial spin dynamics in ultrathin Ni80Fe20 films leading to nutation at a frequency of ∼ 0.1 THz, measured by time-resolved magneto optical Kerr effect (TR-MOKE). The inertial regime has a lifetime of more than 300ps. © 2023 IEEE.","Magnetic Films; Magneto Optical Kerr Effect (MOKE); Nutation; Precession","Binary alloys; Ferromagnetic materials; Iron alloys; Optical Kerr effect; Ultrathin films; Femtoseconds; Ferromagnetic thin films; Inertia terms; Magneto optical kerr effect; Magneto-optical Kerr effects; Nutation; Picoseconds; Precession; Short time scale; Time-scales; Spin dynamics","","","","","Deutsche Forschungsgemeinschaft, DFG, (B11); Deutsche Forschungsgemeinschaft, DFG","ACKNOWLEDGEMENT The work has been funded by the Deutsche Forschungsge-meinschaft (DFG, German Research Foundation) - TRR 173 -268565370 Spin + X: spin in its collective environment (Project B11).","Gilbert T., A phenomenological theory of damping in ferromagnetic materials, IEEE Transactions on Magnetics, 40, 6, pp. 3443-3449, (2004); Ciornei M.-C., Rub J.M., Wegrowe J.-E., Magnetization dynamics in the inertial regime: Nutation predicted at short time scales, Phys. Rev. B, 83, (2011); Makhfudz I., Olive E., Nicolis S., Nutation wave as a platform for ultrafast spin dynamics in ferromagnets, Applied Physics Letters, 117, 13, (2020); Kikuchi T., Tatara G., Spin dynamics with inertia in metallic ferromagnets, Phys. Rev. B, 92, (2015); Neeraj A.N.K.S.E.A.K., Inertial spin dynamics in ferromagnets, Nat. Phys, 17, pp. 245-250, (2021); Unikandanunni V., Medapalli R., Asa M., Albisetti E., Petti D., Bertacco R., Fullerton E.E., Bonetti S., Inertial spin dynamics in epitaxial cobalt films, Phys. Rev. Lett, 129, (2022)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE; Magnetism Society of Japan (MSJ)","2023 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2023","15 May 2023 through 19 May 2023","Sendai","192391","","979-835033836-2","","","English","IEEE Int. Magn. Conf. - Short Pap., INTERMAG Short Papers - Proc.","Conference paper","Final","","Scopus","2-s2.0-85172737856" +"Zhou Y.; Ren Y.; Liu L.; Miao Y.; Wang L.","Zhou, Yiwei (59459897100); Ren, Yifan (59015872100); Liu, Liwang (56746608700); Miao, Yuxuan (59460857100); Wang, Lu (59459155200)","59459897100; 59015872100; 56746608700; 59460857100; 59459155200","Process of Generating Terahertz Waves in Fe Thin Film Simulated by Using Micromagnetic Simulation; [Fe 薄膜中产生太赫兹波的微磁学模拟过程]","2024","Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology","44","11","","993","999","6","0","10.13922/j.cnki.cjvst.202405019","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85211174765&doi=10.13922%2fj.cnki.cjvst.202405019&partnerID=40&md5=cffd226babc409badeb41889e4dd07e7","School of Teacher Education, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; Graduate School of University of Science and Technology of China, Science Island Branch, Hefei, 230026, China; School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China","Zhou Y., School of Teacher Education, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Ren Y., Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China, Graduate School of University of Science and Technology of China, Science Island Branch, Hefei, 230026, China; Liu L., School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Miao Y., School of Teacher Education, Nanjing University of Information Science and Technology, Nanjing, 210044, China; Wang L., School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China","The unique characteristics of terahertz radiation make it a multifunctional tool that can be applied in various fields such as imaging, spectroscopy, communication, materials science, and biomedical applications. In this paper, the dispersion relationship of one-dimensional spin waves, magnetic domain walls, and statistical distribution of magnetic moments under thermal effects in the field of micromagnetics are studied through micromagnetic simulations based on the Landau-Lifshitz-Gilbert equation. Based on these, the three-temperature model is combined to simulate the process of terahertz waves generated by femtosecond laser irradiation on Fe thin film. The component of the electric field intensity of the simulated terahertz wave reached its maximum value at 0.3 ps. From the spectrum of the radiated electric field, it can be seen that the spectral continuity in the y-direction of the radiated electric field intensity is good, without any abrupt changes or interruptions. © 2024 Chinese Vacuum Society. All rights reserved.","Femtosecond laser; LLG equation; Micromagnetism; Terahertz","","","","","","","","Pettine J, Padmanabhan P, Sirica N, Et al., Ultrafast terahertz emission from emerging symmetry-broken materials[J], Light-Science & Applications, 12, 1, (2023); Leitenstorfer A, Moskalenko A S, Kampfrath T, Et al., The 2023 terahertz science and technology roadmap[J], Journal of Physics D-Applied Physics, 56, 22, (2023); Zhang S N, Zhu W H, Li J G, Et al., Coherent terahertz radiation via ultrafast manipulation of spin currents in ferromagnetic heterostructures[J], Acta Physica Sinica, 67, 19, (2018); Huang L, Lee S H, Kim S D, Et al., Universal field-tunable terahertz emission by ultrafast photoinduced demagnetization in Fe, Ni, and Co ferromagnetic films[J], Scientific Reports, 10, 1, (2020); Wu Y, Elyasi M, Qiu X P, Et al., High-performance Thz emitters based on ferromagnetic/nonmagnetic heterostructures[J], Advanced Materials, 29, 4, (2017); Li G, Medapalli R, Mikhaylovskiy R V, Et al., Thz emission from Co/Pt bilayers with varied roughness, crystal structure, and interface intermixing[J], Physical Review Materials, 3, 8, (2019); Salikhov R, Ilyakov I, Korber L, Et al., Coupling of terahertz light with nanometre-wavelength magnon modes via spin–orbit torque[J], Nature Physics, 19, 4, pp. 529-535, (2023); Rongione E, Gueckstock O, Mattern M, Et al., Emission of coherent Thz magnons in an antiferromagnetic insulator triggered by ultrafast spin-phonon interactions[J], Nature Communications, 14, 1, (2023); Yang Y S, Dal Forno S, Battiato M., Modeling spintronic terahertz emitters as a function of spin generation and diffusion geometry[J], Physical Review B, 107, 14, (2023); Zhang W T, Maldonado P, Jin Z M, Et al., Ultrafast terahertz magnetometry[J], Nature Communications, 11, 1, (2020); Liu L W, Ren Y F, Robert W, Et al., Terahertz wave radiation simulation in the Fe thin film[J], Journal of Physics: Condensed. Matter, 36, (2024); Chu X B, Jin Z M, Wu X, Et al., Pulsed far-infrared generation in ferromagnetic heterostructue controlled by photo-thermal effect[J], Acta Physica Sinica, 72, (2023); Beaurepaire E, Merle J C, Daunois A, Et al., Ultrafast spin dynamics in ferromagnetic nickel[J], Physical review letters, 76, 22, pp. 4250-4253, (1996); Zhang J, Yu W, Chen X, Et al., A frequency-domain micromagnetic simulation module based on comsol multiphysics[J], AIP Advances, 13, 5, (2023); Zhang S, Jin Z, Zhu Z, Et al., Bursts of efficient terahertz radiation with saturation effect from metal-based ferromagnetic heterostructures[J], Journal of Physics D: Applied Physics, 51, 3, (2018)","L. Liu; School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China; email: liulw@nuist.edu.cn","","Chinese Vacuum Society","","","","","","16727126","","CKKSD","","Chinese","Zhenkong Kexue yu Jishu Xuebao","Article","Final","","Scopus","2-s2.0-85211174765" +"Garcia-Gaitan F.; Nikolić B.K.","Garcia-Gaitan, Federico (58180449100); Nikolić, Branislav K. (7006055333)","58180449100; 7006055333","Fate of entanglement in magnetism under Lindbladian or non-Markovian dynamics and conditions for their transition to Landau-Lifshitz-Gilbert classical dynamics","2024","Physical Review B","109","18","L180408","","","","1","10.1103/PhysRevB.109.L180408","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85193843075&doi=10.1103%2fPhysRevB.109.L180408&partnerID=40&md5=6cc50c4f2be889d0c1062343f544ccaa","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Garcia-Gaitan F., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","The entanglement of many localized spins (LSs) within solid magnetic materials is a topic of great basic and applied interest, particularly after becoming amenable to experimental scrutiny where recent neutron scattering experiments have witnessed macroscopic entanglement in the ground state (GS) of antiferromagnets persisting even at elevated temperatures. On the other hand, spintronics and magnonics studies assume that LSs of antiferromagnets are in unentangled Néel GS, as well as that they evolve, when pushed out of equilibrium by current or external fields, according to the Landau-Lifshitz-Gilbert (LLG) equation viewing LSs as classical vectors of fixed length. The prerequisite for applicability of the LLG equation is zero entanglement in the underlying many-body quantum state of LSs. In this study, we initialize quantum Heisenberg ferro-or antiferromagnetic chains hosting S=1/2, S=1, or S=5/2 LSs into an unentangled pure state and then evolve them by quantum master equations (QMEs) of Lindblad or non-Markovian type, derived by coupling LSs weakly to a bosonic bath (due to phonons in real materials) or by using additional ""reaction coordinate""in the latter case. The time evolution is initiated by applying an external magnetic field, and entanglement of the ensuing mixed quantum states is monitored by computing its negativity. We find that non-Markovian dynamics never brings entanglement to zero, in the presence of which the vector of spin expectation value changes its length to render the LLG equation inapplicable. Conversely, Lindbladian (i.e., Markovian) dynamics ensures that entanglement goes to 0, thereby enabling quantum-To-classical transition in all cases-S=1/2, S=1, and S=5/2 ferromagnets or S=5/2 antiferromagnets-except for S=1/2 and S=1 antiferromagnets. Finally, we investigate the stability of an entangled antiferromagnetic GS upon suddenly coupling it to bosonic baths. © 2024 American Physical Society.","","Antiferromagnetic materials; Antiferromagnetism; Bosons; Dynamics; Neutron scattering; Quantum entanglement; Spin dynamics; Antiferromagnets; Classical dynamics; Condition; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Localized spin; Macroscopic entanglement; Neutron scattering experiments; Non-markovian dynamics; Quantum state; Ground state","","","","","National Science Foundation, NSF; University of Delaware Materials Research Science and Engineering Center, (DMR-2011824)","Acknowledgments. This research was primarily supported by the U.S. National Science Foundation through the University of Delaware Materials Research Science and Engineering Center, Grant No. DMR-2011824.","Christensen N. B., Ronnow H. M., McMorrow D. F., Harrison A., Perring T. G., Enderle M., Coldea R., Regnault L. 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Status Solidi B, 226, (2001); Davis E., Ye B., Machado F., Meynell S., Wu W., Mittiga T., Schenken W., Joos M., Kobrin B., Lyu Y., Wang Z., Bluvstein D., Choi S., Zu C., Jayich A., Yao N., Probing many-body dynamics in a two-dimensional dipolar spin ensemble, Nat. Phys, 19, (2023); Sbierski B., Bintz M., Chatterjee S., Schuler M., Yao N. Y., Pollet L., Magnetism in the two-dimensional dipolar XY model, Phys. Rev. B, 109, (2024); Camley R. E., Livesey K. L., Consequences of the Dzyaloshinskii-Moriya interaction, Surf. Sci. Rep, 78, (2023); Prosen T., Exact nonequilibrium steady state of an open Hubbard chain, Phys. Rev. Lett, 112, (2014); Queisser F., Schutzhold R., Environment-induced prerelaxation in the Mott-Hubbard model, Phys. Rev. B, 99, (2019); Lee J. S., Yeo J., Comment on ""Universal Lindblad equation for open quantum systems; Nathan F., Rudner M. S., High accuracy steady states obtained from the universal Lindblad equation; Garcia-Palacios J. L., Lazaro F. J., Langevin-dynamics study of the dynamical properties of small magnetic particles, Phys. Rev. B, 58, (1998); Zou J., Kim S. K., Tserkovnyak Y., Tuning entanglement by squeezing magnons in anisotropic magnets, Phys. Rev. B, 101, (2020); Iemini F., Chang D., Marino J., Dynamics of inhomogeneous spin ensembles with all-To-All interactions: Breaking permutational invariance, Phys. Rev. A, 109, (2024); Seif A., Wang Y.-X., Clerk A. A., Distinguishing between quantum and classical Markovian dephasing dissipation, Phys. Rev. Lett, 128, (2022); Nielsen M. A., Chuang I. L., Quantum Computation and Quantum Information: 10th Anniversary Edition, (2010); Cresser J. D., Anders J., Weak and ultrastrong coupling limits of the quantum mean force Gibbs state, Phys. Rev. Lett, 127, (2021); Schuckert A., Pineiro Orioli A., Berges J., Nonequilibrium quantum spin dynamics from two-particle irreducible functional integral techniques in the Schwinger boson representation, Phys. Rev. B, 98, (2018)","B.K. Nikolić; Department of Physics and Astronomy, University of Delaware, Newark, 19716, United States; email: bnikolic@udel.edu","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85193843075" +"Boufligha M.; Bessissa L.; Mahi D.","Boufligha, Messaoud (58658244800); Bessissa, Lakhdar (56028814600); Mahi, Djillali (6603280959)","58658244800; 56028814600; 6603280959","Magnetization Dynamics Modeling in a Like Iron-Silicon Thin Film by the Micromagnetic Approach","2023","Journal of Magnetics","28","3","","245","250","5","0","10.4283/JMAG.2023.28.3.245","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85174601194&doi=10.4283%2fJMAG.2023.28.3.245&partnerID=40&md5=fcd754c0fd6e7f2da3275687f18f0020","Electrical Engineering Department, Faculty of Technology, Amar Telidji University, Laghouat, Algeria; Materials Science and Informatics Laboratory, University Ziane Achour of Djelfa, Algeria","Boufligha M., Electrical Engineering Department, Faculty of Technology, Amar Telidji University, Laghouat, Algeria; Bessissa L., Materials Science and Informatics Laboratory, University Ziane Achour of Djelfa, Algeria; Mahi D., Electrical Engineering Department, Faculty of Technology, Amar Telidji University, Laghouat, Algeria","Iron-silicon thin films used as a single layer or in sandwich structures are currently regarded as a promising candidate in high magnetic sensors. A detailed understanding of magnetization dynamics in such thin films is of great interest. In this work, we only focused on modeling the magnetization reversal. Numerical solution to the nonlinear Landau-Lifshitz-Gilbert (LLG) equation can be used to conduct the study. With the help of our developed Matlab code, the simulations were carried out. External field strength, damping parameter and temperature all have an impact on the speed of the magnetization reversal. The validation of our computations is achieved via a separate simulation. It relates to the solution of the standard problem proposed by the micro-magnetic Modeling Activity G roup (μMAG). The results are in agreement with the ones presented in the National Institute of Standards and Technology (NIST) website. © The Korean Magnetics Society. All rights reserved.","damping parameter; Fe-Si alloys; magnetization reversal; micromagnetic; simulation","","","","","","","","Elanjeitsnni V. P., Vadivu K. S., Prasanth B. M., Mater. Res. Express, 9, (2022); Li X. N., Li S. B., Nie L. F., Li H., Dong C., Jang X. J., Thin Solid Films, 518, (2010); Wasa K., Kitabatake M., Adachi H., Thin Film Materials Technology, (2004); Gaoyuan O., Xi C., Yongfeng L., Chad M., Jun C., J. Magn. Magn. Mater, 481, (2019); Ercument Y., Gizem D.Y., (CSJ), 38, (2017); Jantaratana P., Sirisathitkul C., J. Magn. Magn. Mater, 281, (2004); Phan M., Peng H., Progress in Materials Science, 53, (2008); Barman A., Mondal S., Sahoo S., De A., J. Appl. Phys, 128, (2020); Bertotti G., Mayergoyz I. D., Serpic C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Couture S., Chang R., Volvach I., Goncharov A., Lomakin V., IEEE, 53, (2017); Zhu B., Lo C. C. H., Lee S. J., Jiles D. C., J. Appl. Physics, 89, (2001); Voltairas P. A., Fotiadis D. I., Massalas C. V., IJES, 38, (2000); Bercov D. V., Handbook of Magnetism and Advanced Magnetic Materials, (2007); Fidler J., Schrefl T., Tsiantos V. D., Scoltz W., Suess D., Computational Materials Science, 24, (2002); Quondam A. S., Pompei M., IEEE, 226, (2015); Nouar R., (2009); Kotb M., Saudy A. H., Hassballa S., Eloker M. M., Modern Trends in Physics Research, 86, (2013); Ting J. M., Hung S. W., Diamond and Related Materials, 15, (2006); Meydam T., Kockar H., Williams P. I., J. Magn. Magn. Mater, 254, (2003); Gonzalez F., Houbaert Y., Revista de Metalurgia, 49, (2013); Donahue M. J., OOMMF User’s guide, 1, (2000); Scheinfein M. R., Price E. A., LLGMicromagnetic Simulaor Manual v.01, (2015); Brian R. H., Ronald L. L., Jonathan M. R., A guide to Matlab for Beguinners and Experienced Users, (2001); Boufligha M., AMSE Journals, Advances D, 21, (2016); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo B., Azzerboni A., Physica B, 403, (2008); Nakatani Y., Uesaka Y., Hayachi N., J. Appl. Phys, 28, (1989); Jiles D., Introduction to Magnetism and Magnetic Materials, (2015); Fiorillo F., Measurements and Characterization of Magnetic Materials, (2004); Bozorth R. M., Ferromagnetism, (1993); Tsiantos V., Scholz W., Suess D., Schrefl T., Fidler J., J. Magn. Magn. Mater, 242, (2002)","L. Bessissa; Materials Science and Informatics Laboratory, University Ziane Achour of Djelfa, Algeria; email: lakhdarbessissa@gmail.com","","Seoul National University 501-321","","","","","","12261750","","","","English","J. Magn.","Article","Final","","Scopus","2-s2.0-85174601194" +"Mehta R.; Moalic M.; Krawczyk M.; Saha S.","Mehta, R. (7402786449); Moalic, M. (57658316000); Krawczyk, M. (56213676300); Saha, S. (54403921100)","7402786449; 57658316000; 56213676300; 54403921100","Tunability of spin-wave spectra in a 2D triangular shaped magnonic fractals","2023","Journal of Physics Condensed Matter","35","32","324002","","","","4","10.1088/1361-648X/acd15f","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85159550099&doi=10.1088%2f1361-648X%2facd15f&partnerID=40&md5=10c5c981103c4e0f1c2c0d38ead1fa44","Department of Physics, Ashoka University, Haryana, Sonipat, 131029, India; Institute of Spintronic and Quantum Information, Faculty of Physics, Adam Mickiewicz University, Poznan Uniwersytetu Poznanskiego 2, Poznan, PL-61-614, Poland","Mehta R., Department of Physics, Ashoka University, Haryana, Sonipat, 131029, India; Moalic M., Institute of Spintronic and Quantum Information, Faculty of Physics, Adam Mickiewicz University, Poznan Uniwersytetu Poznanskiego 2, Poznan, PL-61-614, Poland; Krawczyk M., Institute of Spintronic and Quantum Information, Faculty of Physics, Adam Mickiewicz University, Poznan Uniwersytetu Poznanskiego 2, Poznan, PL-61-614, Poland; Saha S., Department of Physics, Ashoka University, Haryana, Sonipat, 131029, India","Reprogramming the structure of the magnonic bands during their operation is important for controlling spin waves in magnonic devices. Here, we report the tunability of the spin-wave spectra for a triangular shaped deterministic magnonic fractal, which is known as Sierpinski triangle by solving the Landau-Lifshitz-Gilbert equation using a micromagnetic simulations. The spin-wave dynamics change significantly with the variation of iteration number. A wide frequency gap is observed for a structure with an iteration number exceeding some value and a plenty of mini-frequency bandgaps at structures with high iteration number. The frequency gap could be controlled by varying the strength of the magnetic field. A sixfold symmetry in the frequency gap is observed with the variation of the azimuthal angle of the external magnetic field. The spatial distributions of the spin-wave modes allow to identify the bands surrounding the gap. The observations are important for the application of magnetic fractals as a reconfigurable aperiodic magnonic crystals. © 2023 IOP Publishing Ltd.","LLG equation; magnetic fractal; magnetization dynamics; magnonics; micro-magnetic simulation; spin wave","Fractals; Magnetic fields; Multilayers; Spin dynamics; Deterministics; Frequency gaps; Iteration numbers; LLG equation; Magnetic fractal; Magnetization dynamics; Magnonic; Micromagnetic simulations; Spin-wave spectrum; Tunabilities; article; fractal analysis; magnetic field; simulation; Spin waves","","","","","Ashoka University; Science and Engineering Research Board, SERB, (SRG/2022/000191); Narodowe Centrum Nauki, NCN, (2020/37/B/ST3/03936)","S S gratefully acknowledges the financial support of SERB with file Number SRG/2022/000191 and the Axis Grant at Ashoka University for the funding. S S and R M acknowledge the HPC computer center at Ashoka University. Many thanks to Professor Sabyasachi Bhattacharya, Professor Somendra Mohan Bhattacharya, and Professor Varsha Banerjee for fruitful discussions. M M and M K acknowledges the financial support of NCN Poland Project No. 2020/37/B/ST3/03936.","Tehrani S, Chen E, Durlam M, DeHerrera M, Slaughter J M, Shi J, Kerszykowski G, J. Appl. Phys, 85, (1999); Kryder M H, Gage E C, Mcdaniel T W, Challener W A, Rottmayer R E, Ju G, Hsia Y-T, Erden M F, Proc. IEEE, 96, (2008); Parkin S S P, Hayashi M, Thomas L, Science, 320, (2008); Thomson T, Hu G, Terris B D, Phys. Rev. Lett, 96, (2006); Allwood D A, Xiong G, Faulkner C C, Atkinson D, Petit D, Cowburn R P, Science, (2005); Lenk B, Ulrichs H, Garbs F, Munzenberg M, Phys. Rep, 507, (2011); Kruglyak V, Demokritov O, Grundler D, J. Phys. D: Appl. Phys, 43, (2010); Neusser S, Grundler D, Adv. Mater, 21, (2009); Kim S K, J. Phys. D: Appl. Phys, 43, (2010); Chumak A V, Serga A A, Hillebrands B, Kostylev M P, Appl. Phys. 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Phys, 49, (2016); Shechtman D, Blech I, Gratias D, Cahn J W, Phys. Rev. Lett, 53, (1984); Shen X, Li L, Cui W, Feng Y, Int. J. Heat Mass Transf, 121, (2018); McMullen C, Nagoya Math. J, 96, (1984); Alexander S, Laermans C, Orbach R, Rosenberg H M, Phys. Rev. B, 28, (1983); Nakayama T, Yakubo K, Orbach R L, Rev. Mod. Phys, 66, (1994); Swoboda C, Martens M, Meier G, Phys. Rev. B, 91, (2015); Zhou J, Zelent M, Luo Z, Scagnoli V, Krawczyk M, Heyderman L J, Saha S, Phys. Rev. B, 105, (2022); Donahue M, Porter D G, OOMMF user’s guide, (1999); Kumar D, Dmytriiev O, Ponraj S, Barman A, J. Phys. D: Appl. Phys, 45, (2011); Vansteenkiste A, Leliaert J, Dvornik M, Helsen M, Garcia-Sanchez F, Van Waeyenberge B, The design and verification of MuMax3, AIP Adv, 4, (2014); Cowburn R P, Adeyeye A O, Welland M E, Phys. Rev. Lett, 81, (1998)","S. Saha; Department of Physics, Ashoka University, Sonipat, Haryana, 131029, India; email: susmita.saha@ashoka.edu.in","","Institute of Physics","","","","","","09538984","","JCOME","37116510","English","J Phys Condens Matter","Article","Final","","Scopus","2-s2.0-85159550099" +"Gonzalez-Chavez D.E.; Zamudio G.P.; Sommer R.L.","Gonzalez-Chavez, D.E. (55859826500); Zamudio, G.P. (58817771300); Sommer, R.L. (8514725600)","55859826500; 58817771300; 8514725600","Solutions to the Landau–Lifshitz–Gilbert equation in the frequency space: Discretization schemes for the dynamic-matrix approach","2024","Journal of Magnetism and Magnetic Materials","603","","172179","","","","1","10.1016/j.jmmm.2024.172179","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85195204257&doi=10.1016%2fj.jmmm.2024.172179&partnerID=40&md5=5b2fd6ee2935bbcf77c13a0dad62ef0f","Centro Brasileiro de Pesquisas Físicas, RJ, Rio de Janeiro, 22290-180, Brazil","Gonzalez-Chavez D.E., Centro Brasileiro de Pesquisas Físicas, RJ, Rio de Janeiro, 22290-180, Brazil; Zamudio G.P., Centro Brasileiro de Pesquisas Físicas, RJ, Rio de Janeiro, 22290-180, Brazil; Sommer R.L., Centro Brasileiro de Pesquisas Físicas, RJ, Rio de Janeiro, 22290-180, Brazil","The dynamic matrix method addresses the Landau–Lifshitz–Gilbert (LLG) equation in the frequency domain by transforming it into an eigenproblem. Subsequent numerical solutions are derived from the eigenvalues and eigenvectors of the dynamic matrix. In this work we explore discretization methods needed to obtain a matrix representation of the dynamic operator, a fundamental counterpart of the dynamic matrix. Our approach opens a new set of linear algebra tools for the dynamic matrix method and expose the approximations and limitations intrinsic to it. Moreover, our discretization algorithms can be applied to various discretization schemes, extending beyond micromagnetism problems. We present some application examples, including a technique to obtain the dynamic matrix directly from the magnetic free energy function of an ensemble of macrospins, and an algorithmic method to calculate numerical micromagnetic kernels, including plane wave kernels. We also show how to exploit symmetries and reduce the numerical size of micromagnetic dynamic-matrix problems by a change of basis. This procedure significantly reduces the size of the dynamic matrix by several orders of magnitude while maintaining high numerical precision. Additionally, we calculate analytical approximations for the dispersion relations in magnonic crystals. This work contributes to the understanding of the current magnetization dynamics methods, and could help the development and formulations of novel analytical and numerical methods for solving the LLG equation within the frequency domain. © 2024 Elsevier B.V.","Magnonics; Micromagnetics; Spin waves","Discrete event simulation; Eigenvalues and eigenfunctions; Free energy; Frequency domain analysis; Numerical methods; Discretization scheme; Frequency domains; Frequency spaces; Landau-Lifshitz-Gilbert equations; Magnonic; matrix; Matrix approach; Matrix methods; Micromagnetics; Space discretizations; Matrix algebra","","","","","Carlos Chagas Filho Research Support Foundation of Rio de Janeiro State; Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ, (E-26/200.594/2022, E-26/202.083/2022); Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, FAPERJ","Funding text 1: This work was funded by the Carlos Chagas Filho Research Support Foundation of Rio de Janeiro State (FAPERJ), Brazil, through grants E-26/200.594/2022 and E-26/202.083/2022.; Funding text 2: This work was funded by the Carlos Chagas Filho Research Support Foundation of Rio de Janeiro State (FAPERJ) , through grants E-26/200.594/2022 and E-26/202.083/2022 .","Fert A., Nobel lecture: Origin, development, and future of spintronics, Rev. 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Matter., 33, (2021); Chumak A.V., Kabos P., Wu M., Abert C., Adelmann C., Adeyeye A.O., Akerman J., Aliev F.G., Anane A., Awad A., Back C.H., Barman A., Bauer G.E.W., Becherer M., Beginin E.N., Bittencourt V.A.S.V., Blanter Y.M., Bortolotti P., Boventer I., Bozhko D.A., Bunyaev S.A., Carmiggelt J.J., Cheenikundil R.R., Ciubotaru F., Cotofana S., Csaba G., Dobrovolskiy O.V., Dubs C., Elyasi M., Fripp K.G., Fulara H., Golovchanskiy I.A., Gonzalez-Ballestero C., Graczyk P., Grundler D., Gruszecki P., Gubbiotti G., Guslienko K., Haldar A., Hamdioui S., Hertel R., Hillebrands B., Hioki T., Houshang A., Hu C.-M., Huebl H., Huth M., Iacocca E., Jungfleisch M.B., Kakazei G.N., Khitun A., Khymyn R., Kikkawa T., Klaui M., Klein O., Kl os J.W., Knauer S., Koraltan S., Kostylev M., Krawczyk M., Krivorotov I.N., Kruglyak V.V., Lachance-Quirion D., Ladak S., Lebrun R., Li Y., Lindner M., Macedo R., Mayr S., Melkov G.A., Mieszczak S., Nakamura Y., Nembach H.T., Nikitin A.A., Nikitov S.A., Novosad V., Otalora J.A., Otani Y., Papp A., Pigeau B., Pirro P., Porod W., Porrati F., Qin H., Rana B., Reimann T., Riente F., Romero-Isart O., Ross A., Sadovnikov A.V., Safin A.R., Saitoh E., Schmidt G., Schultheiss H., Schultheiss K., Serga A.A., Sharma S., Shaw J.M., Suess D., Surzhenko O., Szulc K., Taniguchi T., Urbanek M., Usami K., Ustinov A.B., van der Sar T., van Dijken S., Vasyuchka V.I., Verba R., Kusminskiy S.V., Wang Q., Weides M., Weiler M., Wintz S., Wolski S.P., Zhang X., Advances in magnetics roadmap on spin-wave computing, IEEE Trans. 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Mater., 421, pp. 428-439, (2017); Gubbiotti G., Tacchi S., Carlotti G., Singh N., Goolaup S., Adeyeye A.O., Kostylev M., Collective spin modes in monodimensional magnonic crystals consisting of dipolarly coupled nanowires, Appl. Phys. Lett., 90, (2007); Kostylev M., Schrader P., Stamps R.L., Gubbiotti G., Carlotti G., Adeyeye A.O., Goolaup S., Singh N., Partial frequency band gap in one-dimensional magnonic crystals, Appl. Phys. Lett., 92, (2008); Wang Z.K., Zhang V.L., Lim H.S., Ng S.C., Kuok M.H., Jain S., Adeyeye A.O., Observation of frequency band gaps in a one-dimensional nanostructured magnonic crystal, Appl. Phys. Lett., 94, (2009)","D.E. Gonzalez-Chavez; Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, RJ, 22290-180, Brazil; email: diegogch@cbpf.br","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85195204257" +"Chakraborty T.; Pradhan P.","Chakraborty, Tanmoy (57217114415); Pradhan, Punyabrata (24177162800)","57217114415; 24177162800","Time-dependent properties of run-and-tumble particles: Density relaxation","2024","Physical Review E","109","2","024124","","","","3","10.1103/PhysRevE.109.024124","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85186122519&doi=10.1103%2fPhysRevE.109.024124&partnerID=40&md5=7b83d95854d661a6414a11f0c3dc9cfd","Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Kolkata, Salt Lake, 700106, India","Chakraborty T., Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Kolkata, Salt Lake, 700106, India; Pradhan P., Department of Physics of Complex Systems, S. N. Bose National Centre for Basic Sciences, Block-JD, Kolkata, Salt Lake, 700106, India","We characterize collective diffusion of hardcore run-and-tumble particles (RTPs) by explicitly calculating the bulk-diffusion coefficient D(ρ,γ) for arbitrary density ρ and tumbling rate γ, in systems on a d-dimensional periodic lattice. We study two minimal models of RTPs: Model I is the standard version of hardcore RTPs introduced in [Phys. Rev. E 89, 012706 (2014)10.1103/PhysRevE.89.012706], whereas model II is a long-ranged lattice gas (LLG) with hardcore exclusion, an analytically tractable variant of model I. We calculate the bulk-diffusion coefficient analytically for model II and numerically for model I through an efficient Monte Carlo algorithm; notably, both models have qualitatively similar features. In the strong-persistence limit γ→0 (i.e., dimensionless ratio r0γ/v→0), with v and r0 being the self-propulsion speed and particle diameter, respectively, the fascinating interplay between persistence and interaction is quantified in terms of two length scales: (i) persistence length lp=v/γ and (ii) a ""mean free path,""being a measure of the average empty stretch or gap size in the hopping direction. We find that the bulk-diffusion coefficient varies as a power law in a wide range of density: D ρ-α, with exponent α gradually crossing over from α=2 at high densities to α=0 at low densities. As a result, the density relaxation is governed by a nonlinear diffusion equation with anomalous spatiotemporal scaling. In the thermodynamic limit, we show that the bulk-diffusion coefficient - for ρ,γ→0 with ρ/γ fixed - has a scaling form D(ρ,γ)=D(0)F(ρav/γ), where a∼r0d-1 is particle cross section and D(0) is proportional to the diffusion coefficient of noninteracting particles; the scaling function F(ψ) is calculated analytically for model II (LLG) and numerically for model I. Our arguments are independent of dimensions and microscopic details. © 2024 American Physical Society.","","Nonlinear equations; Bulk diffusion coefficients; Collective diffusion; Density relaxation; Hardcore; Lattice gas; Minimal model; Model I; Particle densities; Periodic lattices; Time-dependent properties; algorithm; article; controlled study; crossing over; density; diffusion; diffusion coefficient; male; thermodynamics; velocity; Diffusion","","","","","Council of Scientific and Industrial Research, India, CSIR; Science and Engineering Research Board, SERB, (09/575 (0124)/2019-EMRI, MTR/2019/000386)","We thank Subhadip Chakraborti, Arghya Das, Rahul Dandekar, and R. Rajesh for discussions. P.P. gratefully acknowledges the Science and Engineering Research Board (SERB), India, under Grant No. MTR/2019/000386, for financial support. T.C. acknowledges a research fellowship [Grant No. 09/575 (0124)/2019-EMRI] from the Council of Scientific and Industrial Research (CSIR), India.","Marchetti M. C., Joanny J. F., Ramaswamy S., Liverpool T. B., Prost J., Rao M., Simha R. A., Rev. Mod. Phys, 85, (2013); Wu X.-L., Libchaber A., Phys. Rev. Lett, 84, (2000); Wang B., Anthony S. M., Bae S. C., Granick S., Proc. Natl. Acad. Sci. USA, 106, (2009); Leptos K. C., Guasto J. S., Gollub J. P., Pesci A. I., Goldstein R. E., Phys. Rev. Lett, 103, (2009); Kudrolli A., Phys. Rev. Lett, 104, (2010); Wang B., Kuo J., Bae S. C., Granick S., Nat. Mater, 11, (2012); Ariel G., Rabani A., Benisty S., Partridge J. D., Harshey R. M., Be'Er A., Nat. Commun, 6, (2015); Lopez H. M., Gachelin J., Douarche C., Auradou H., Clement E., Phys. Rev. Lett, 115, (2015); Cavagna A., Conti D., Creato C., Del Castello L., Giardina I., Grigera T. S., Melillo S., Parisi L., Viale M., Nat. Phys, 13, (2017); Sokolov A., Rubio L. D., Brady J. F., Aranson I. 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(55566203800)","57194501995; 14029622100; 35598581900; 55566203800","Impact of Multi-Domain Microscopic Interactions on Magnetic Tunnel Junction's Static and Transient Characteristics","2024","Device Research Conference - Conference Digest, DRC","","","","","","","0","10.1109/DRC61706.2024.10605360","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85201063018&doi=10.1109%2fDRC61706.2024.10605360&partnerID=40&md5=8813fce7936fe05111e860042971a7eb","University of Texas at Austin, Austin, 78703, TX, United States; Indian Institute of Technology - Kanpur, Uttar Pradesh, Kanpur, 208016, India","Pandey N., University of Texas at Austin, Austin, 78703, TX, United States; Chauhan Y.S., Indian Institute of Technology - Kanpur, Uttar Pradesh, Kanpur, 208016, India; Register L.F., University of Texas at Austin, Austin, 78703, TX, United States; Banerjee S.K., University of Texas at Austin, Austin, 78703, TX, United States","This paper investigates the impact of multi-domain dynamics on the static and transient properties of magnetic tunnel junctions (MTJs). A phase-field model, derived from the coupled solutions of magnetostatics, thermodynamics, and the Landau-Lifshitz-Gilbert (LLG) equation, captures the multi-domain texture. The increased density of domains in the free layer reduces the device's switching speed and tunnel magnetic resistance (TMR). Moreover, the critical switching current density significantly depends on the multi-domain configuration. Domain density is altered by altering device physical parameters (free layer thickness, MgO layer thickness) and material parameters (anisotropy, Dzyaloshinskii-Moriya Interaction (DMI) constant) toward achieving optimal performance in terms of the highest TMR and switching speed. Finally, a device design curve is established to select appropriate physical and material parameters for maximum performance. © 2024 IEEE.","","Magnesia; Magnetic devices; Magnetic domains; Textures; Thermodynamics; Tunnel junctions; Free layers; Magnetic resistance; Magnetic tunnel junction; Materials parameters; Microscopic interaction; Multi-domains; Physical parameters; Static characteristic; Switching speed; Transient characteristic; Magnetostatics","","","","","","","Ikeda S., Et al., Nature Materials, 9, 9, pp. 721-724, (2010); Sankey J., Et al., Nature Phys, 4, pp. 67-71, (2008); Aggarwal S., Et al., IEDM Tech Dig, pp. 211-214, (2019); Kittel C., Phys. Rev., 70, pp. 965-971, (1946); Lemesh I., Et al., Phys. Rev. B, 95, (2017); Wang J.-J., Et al., Acta Materialia, 176, (2019); Pandey N., Chauhan Y.S., IEEE TED, 70, 5, pp. 2304-2311, (2023); Datta D., Et al., IEEE TNANO, 11, 2, pp. 261-272, (2012)","N. Pandey; University of Texas at Austin, Austin, 78703, United States; email: pandey@utexas.edu","","Institute of Electrical and Electronics Engineers Inc.","","82nd Device Research Conference, DRC 2024","24 June 2024 through 26 June 2024","College Park","201461","15483770","979-835037373-8","","","English","Dev. Res. Conf. Conf. Dig.","Conference paper","Final","","Scopus","2-s2.0-85201063018" +"Xu F.; Li G.; Chen J.; Yu Z.; Zhang L.; Wang B.; Wang J.","Xu, Fuming (35202423700); Li, Gaoyang (57386693200); Chen, Jian (55711840800); Yu, Zhizhou (55929073600); Zhang, Lei (57207272242); Wang, Baigeng (7405919045); Wang, Jian (57214694529)","35202423700; 57386693200; 55711840800; 55929073600; 57207272242; 7405919045; 57214694529","Unified framework of the microscopic Landau-Lifshitz-Gilbert equation and its application to skyrmion dynamics","2023","Physical Review B","108","14","144409","","","","5","10.1103/PhysRevB.108.144409","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85177620791&doi=10.1103%2fPhysRevB.108.144409&partnerID=40&md5=bcc099e12c48b4856d8092b45025329d","College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China; Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong; School of Physics and Technology, Nanjing Normal University, Nanjing, 210023, China; State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China; National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China","Xu F., College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China; Li G., College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China; Chen J., Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong; Yu Z., School of Physics and Technology, Nanjing Normal University, Nanjing, 210023, China; Zhang L., State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China; Wang B., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; Wang J., College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China, Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong","The Landau-Lifshitz-Gilbert (LLG) equation is widely used to describe magnetization dynamics. We develop a unified framework of the microscopic LLG equation based on the nonequilibrium Green's function formalism. We present a unified treatment for expressing the microscopic LLG equation in several limiting cases, including the adiabatic, inertial, and nonadiabatic limits with respect to the precession frequency for a magnetization with fixed magnitude, as well as the spatial adiabatic limit for the magnetization with slow variation in both its magnitude and direction. The coefficients of those terms in the microscopic LLG equation are explicitly expressed in terms of nonequilibrium Green's functions. As a concrete example, this microscopic theory is applied to simulate the dynamics of a magnetic skyrmion driven by quantum parametric pumping. Our work provides a practical formalism of the microscopic LLG equation for exploring magnetization dynamics. © 2023 American Physical Society.","","Dynamics; Equation based; ITS applications; Landau-Lifshitz-Gilbert equations; Limiting case; Magnetization dynamics; Non-adiabatic; Non-equilibrium Green's function formalism; Precession frequency; Skyrmion dynamics; Unified framework; Magnetization","","","","","Fund for Shanxi “1331 Project; National Natural Science Foundation of China, NSFC, (12034014, 12074190, 12074230, 12174262); National Natural Science Foundation of China, NSFC","This work was supported by the National Natural Science Foundation of China (Grants No. 12034014, No. 12174262, No. 12074230, and No. 12074190). L.Z. thanks the Fund for Shanxi “1331 Project.”","Ardavan A., Rival O., Morton J. J. L., Blundell S. J., Tyryshkin A. M., Timco G. A., Winpenny R. E. P., Phys. Rev. Lett, 98, (2007); Garg A., Europhys. Lett, 22, (1993); Friedman J. R., Sarachik M. 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B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85177620791" +"Jin X.-W.; Liu Y.; Yang Z.-Y.; Liao Z.-M.; Jing G.; Yang W.-L.","Jin, Xin-Wei (57203688907); Liu, Yanan (57216668385); Yang, Zhan-Ying (7405433561); Liao, Zhi-Min (34974444500); Jing, Guangyin (10641698900); Yang, Wen-Li (7407757708)","57203688907; 57216668385; 7405433561; 34974444500; 10641698900; 7407757708","Hidden chiral mode self-generated from intrinsic magnetic heterogeneity","2024","Physical Review B","110","18","184424","","","","0","10.1103/PhysRevB.110.184424","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85210320215&doi=10.1103%2fPhysRevB.110.184424&partnerID=40&md5=e2407b17acdf54fa048da44aaa13127b","School of Physics, Northwest University, Xi'an, 710127, China; Department of Physics, Zhejiang Normal University, Jinhua, 321004, China; Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China; Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, 710127, China; School of Physics, Peking University, Beijing, 100871, China; Institute of Physics, Northwest University, Xi'an, 710127, China","Jin X.-W., School of Physics, Northwest University, Xi'an, 710127, China, Department of Physics, Zhejiang Normal University, Jinhua, 321004, China, Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China; Liu Y., School of Physics, Northwest University, Xi'an, 710127, China; Yang Z.-Y., School of Physics, Northwest University, Xi'an, 710127, China, Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, 710127, China; Liao Z.-M., School of Physics, Peking University, Beijing, 100871, China; Jing G., School of Physics, Northwest University, Xi'an, 710127, China, Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, 710127, China; Yang W.-L., Peng Huanwu Center for Fundamental Theory, Xi'an, 710127, China, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an, 710127, China, Institute of Physics, Northwest University, Xi'an, 710127, China","We discovered a family of symmetry-breaking magnetic soliton modes in isotropic ferromagnets, recognized as chiral magnetic solitons: left-handed, right-handed, and neutral magnetic solitons. In practical magnetic systems, the lifetime of these solitons is estimated to be in the nanosecond range due to damping effects, accounting for their absence in experimental observations thus far. Solving the Landau-Lifshitz-Gilbert(LLG) equation, the governing equation for magnetic dynamics, poses an exceptional challenge, rendering it a longstanding problem. Theoretically, we employed a sophisticated mathematical geometric mapping method to derive an exact solution to the LLG equation and uncovered these hidden chiral magnetic solitons. To facilitate the experimental realization and manipulation of unique magnetic soliton states, we proposed a scheme to regulate these chiral magnetic solitons using spin-transfer torque induced by spin currents. This approach holds promise for opening new avenues in spintronic applications based on chiral magnetic solitons. © 2024 American Physical Society.","","Phonons; Spin dynamics; Spin waves; Ferromagnets; Isotropics; Landau-Lifshitz-Gilbert equations; Lefthanded; Magnetic heterogeneity; Magnetic solitons; Magnetic system; Nanosecond range; Right handed; Symmetry breakings; Solitons","","","","","Natural Science Basic Research Program of Shaanxi Province, (2021JCW-19, 2023-JC-JQ-02); Natural Science Basic Research Program of Shaanxi Province; National Natural Science Foundation of China, NSFC, (12247103, 12275213, 12174306); National Natural Science Foundation of China, NSFC","The authors thank Prof. Hai-Ming Yu, Prof. Li-Chen Zhao, Prof. Jie Liu, and Prof. Chuanpu Liu for their helpful discussions. This work was supported by the National Natural Science Foundation of China (No. 12275213, No. 12174306, No. 12247103), and Natural Science Basic Research Program of Shaanxi (2023-JC-JQ-02, 2021JCW-19).","Kamenetskii E., Chirality, Magnetism and Magnetoelectricity, (2021); Yang S.-H., Naaman R., Paltiel Y., Parkin S. S., Chiral spintronics, Nat. Rev. Phys, 3, (2021); Cheong S.-W., Talbayev D., Kiryukhin V., Saxena A., Broken symmetries, non-reciprocity, and multiferroicity, npj Quantum Mater, 3, (2018); Yu T., Luo Z., Bauer G. E., Chirality as generalized spin-orbit interaction in spintronics, Phys. Rep, 1009, (2023); Kim S. K., Tserkovnyak Y., Chiral edge mode in the coupled dynamics of magnetic solitons in a honeycomb lattice, Phys. Rev. Lett, 119, (2017); Yu T., Zhang Y.-X., Sharma S., Zhang X., Blanter Y. M., Bauer G. E., Magnon accumulation in chirally coupled magnets, Phys. Rev. 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Liu; School of Physics, Northwest University, Xi'an, 710127, China; email: yanan.liu@nwu.edu.cn","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85210320215" +"Suresh A.; Nikolić B.K.","Suresh, Abhin (57217281246); Nikolić, Branislav K. (7006055333)","57217281246; 7006055333","Quantum classical approach to spin and charge pumping and the ensuing radiation in terahertz spintronics: Example of the ultrafast light-driven Weyl antiferromagnet Mn3Sn","2023","Physical Review B","107","17","174421","","","","5","10.1103/PhysRevB.107.174421","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85161138652&doi=10.1103%2fPhysRevB.107.174421&partnerID=40&md5=a0ad9e6ba3e4bfdf2b4ca7c5b3b5dab3","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Suresh A., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","The interaction of a femtosecond laser pulse with magnetic materials has been intensely studied for more than two decades in order to understand ultrafast demagnetization in single magnetic layers or terahertz emission from their bilayers with nonmagnetic spin-orbit (SO) materials. However, in contrast to well-understood spin and charge pumping by dynamical magnetization in spintronic systems driven by microwaves or current injection, analogous processes in light-driven magnets and radiation emitted by them remain largely unexplained due to the multiscale nature of the problem. Here we develop a multiscale quantum-classical formalism - where conduction electrons are described by quantum master equation (QME) of the Lindblad type, classical dynamics of local magnetization is described by the Landau-Lifshitz-Gilbert (LLG) equation, and incoming light is described by classical vector potential, while outgoing electromagnetic radiation is computed using the Jefimenko equations for retarded electric and magnetic fields - and apply it to a bilayer of antiferromagnetic Weyl semimetal Mn3Sn, hosting noncollinear local magnetization, and SO-coupled nonmagnetic material. Our QME+LLG+Jefimenko scheme makes it possible to understand how a femtosecond laser pulse directly generates spin and charge pumping and electromagnetic radiation by the Mn3Sn layer, including both odd and even high harmonics (of the pulse center frequency) up to order n≤7. The directly pumped spin current then exerts spin torque on local magnetization whose dynamics, in turn, pumps additional spin and charge currents radiating in the terahertz range. By switching on and off LLG dynamics and SO couplings, we unravel which microscopic mechanism contributes the most to emitted terahertz radiation - charge pumping by local magnetization of Mn3Sn in the presence of its own SO coupling is far more important than standardly assumed (for other types of magnetic layers) spin pumping and subsequent spin-to-charge conversion within the adjacent nonmagnetic SO-coupled material. © 2023 American Physical Society. ","","Dynamics; Electromagnetic wave emission; Femtosecond lasers; Laser pulses; Magnetic fields; Magnetic materials; Magnetization; Manganese alloys; Maxwell equations; Optical pumping; Spin dynamics; Spintronics; Terahertz waves; Bi-layer; Charge pumping; Light driven; Local magnetization; Magnetic layers; Nonmagnetics; Quantum master equations; Quantum-classical; Spin orbits; Spin-pumping; Binary alloys","","","","","University of Delaware Materials Research Science and Engineering Center, (DMR-2011824); National Science Foundation, NSF","This research was primarily supported by the US National Science Foundation through the University of Delaware Materials Research Science and Engineering Center, DMR-2011824.","Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Ultrafast Spin Dynamics in Ferromagnetic Nickel, Phys. Rev. Lett, 76, (1996); Kirilyuk A., Kimel A. V., Rasing T., Ultrafast optical manipulation of magnetic order, Rev. Mod. 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K., Energy flow from a battery to other circuit elements: Role of surface charges, Am. J. Phys, 78, (2010); Jimenez-Cavero P., Gueckstock O., Nadvornik L., Lucas I., Seifert T. S., Wolf M., Rouzegar R., Brouwer P. W., Becker S., Jakob G., Transition of laser-induced terahertz spin currents from torque-to conduction-electron-mediated transport, Phys. Rev. B, 105, (2022); Chen K., Zhang S., Spin Pumping in the Presence of Spin-Orbit Coupling, Phys. Rev. Lett, 114, (2015); Bajpai U., Suresh A., Nikolic B. K., Quantum many-body states and Green's functions of nonequilibrium electron-magnon systems: Localized spin operators versus their mapping to Holstein-Primakoff bosons, Phys. Rev. B, 104, (2021)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85161138652" +"Nallan S.; Zhu J.-G.","Nallan, Shreyes (57219327328); Zhu, Jian-Gang (57226007941)","57219327328; 57226007941","The Effect of Thermal Fields on Spin Hall Switching in Devices Stabilized by In-Plane Magnetocrystalline Anisotropy","2024","2024 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2024 - Proceedings","","","","","","","0","10.1109/INTERMAGShortPapers61879.2024.10576981","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85198939646&doi=10.1109%2fINTERMAGShortPapers61879.2024.10576981&partnerID=40&md5=28e2f3f004bf3f82fa2d3f04b8a7ca6b","Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","Nallan S., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States; Zhu J.-G., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","In this work, we examine the effect of random thermal noise on spin-orbit-torque magnetic random-access-memory (SOT-MRAM) devices stabilized by in-plane uniaxial magnetocrystalline anisotropy. We model these thermal fluctuations using a nondimensionalized random-field model, then quantify the effect of model parameters. We then examine the effect of the thermal background on the SOT-MRAM switching process, and observe a 'smearing out' of switching stochasticity, as well as changes in switching thresholds and dependences on polarization angle and anisotropy strength. Finally, we decouple randomness arising from thermal noise and randomness associated with system nonlinearity to get a fuller picture of the transient dynamics of magnetization trajectories. © 2024 IEEE.","LLG equation; SOT-MRAM; spin Hall effect; thermal fields","Magnetic recording; Magnetocrystalline anisotropy; MRAM devices; Random processes; Stochastic systems; LLG equation; Magnetic random access memory; Memory switching; Modeling parameters; Random field model; Spin orbits; Spin-orbit-torque magnetic random-access-memory; Thermal background; Thermal field; Thermal fluctuations; Spin Hall effect","","","","","","","Shao Q., Li P., Liu L., Zhang W., Roadmap of spin-orbit torques, IEEE Transactions on Magnetics, 57, 7, pp. 1-39, (2021); Nallan S., Zhu J.-G., Spin Hall switching enabled by uniaxial in-plane magnetocrystalline anisotropy, IEEE Transactions on Magnetics, 59, 11, pp. 1-5, (2023); Nallan S., Zhu J.-G., Using transient dynamics to improve SOT-MRAM switching efficiency, 68th Annual Conference on Magnetism and Magnetic Materials, (2023); Slonczewski J.C., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, 1-2, (1996); Brown W.F., Thermal fluctuations of a single-domain particle, Physical Review, 130, 5, (1963)","","","Institute of Electrical and Electronics Engineers Inc.","","2024 IEEE International Magnetic Conference - Short Papers, INTERMAG Short Papers 2024","5 May 2024 through 10 May 2024","Rio de Janeiro","200836","","979-835036221-3","","","English","IEEE Int. Magn. Conf. - Short Pap., INTERMAG Short Papers - Proc.","Conference paper","Final","","Scopus","2-s2.0-85198939646" +"Konakanchi S.T.; Upadhyaya P.","Konakanchi, Shiva T. (57959428100); Upadhyaya, Pramey (36467217400)","57959428100; 36467217400","Characterizing Probabilistic Bits with Quantum Spin Defects","2024","Device Research Conference - Conference Digest, DRC","","","","","","","0","10.1109/DRC61706.2024.10605243","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85201059953&doi=10.1109%2fDRC61706.2024.10605243&partnerID=40&md5=caf879c9464d8e32aff52fd0b95a0d45","Purdue University, Department of Physics and Astronomy, West Lafayette, 47907, IN, United States; Purdue University, Elmore Family School of Electrical and Computer Engineering, West Lafayette, 47907, IN, United States","Konakanchi S.T., Purdue University, Department of Physics and Astronomy, West Lafayette, 47907, IN, United States; Upadhyaya P., Purdue University, Elmore Family School of Electrical and Computer Engineering, West Lafayette, 47907, IN, United States","Low-barrier nanomagnets are attracting significant interest as building blocks (p-bits) of probabilistic computers with the promise of realizing compact random number generators fluctuating at sub-nanosecond time scales. Electrical characterization of such p-bits is challenging and slow as it would require building a full magnetic tunnel junction (MTJ) stack. In this work we propose quantum spin defects such as nitrogen vacancy centers (NV centers) as novel probes for rapidly characterizing magnetic p-bits. Through stochastic Landau-Lifshitz-Gilbert (LLG) equation simulations and analytical calculations, we show that NV relaxometry technique can be used to extract key parameters such as energy barrier and the so-called attempt time of a p-bit over a wide range of fluctuation frequencies. Moreover, thanks to the atomic size of the NV sensors and the weak magnetic fields they generate on the sample, this technique has ~10's nm resolution and is noninvasive. © 2024 IEEE.","","Number theory; Random number generation; Stochastic systems; Tunnel junctions; Building blockes; Electrical characterization; Magnetic tunnel junction; Nanomagnets; Nanosecond time scale; Nitrogen-vacancy center; Probabilistics; Quantum spin; Random number generators; Subnanosecond; Defects","","","","","National Science Foundation, NSF, (1944635); NSF DMREF, (2324203)","We acknowledge funding from NSF CAREER grant:1944635 and NSF DMREF grant: 2324203","Kaiser J., Et al., (2021); Camsari K.Y., Et al., IEEE Electron Device Lett., 38, (2017); Casola F., Et al., Nat. Rev. Mater., 3, (2018); Schafer-Nolte E., Et al., Phys. Rev. Lett., 113, (2014)","S.T. Konakanchi; Purdue University, Department of Physics and Astronomy, West Lafayette, 47907, United States; email: skonakan@purdue.com","","Institute of Electrical and Electronics Engineers Inc.","","82nd Device Research Conference, DRC 2024","24 June 2024 through 26 June 2024","College Park","201461","15483770","979-835037373-8","","","English","Dev. Res. Conf. Conf. Dig.","Conference paper","Final","","Scopus","2-s2.0-85201059953" +"Zhou J.; Li Y.; Zhang C.","Zhou, Jiapeng (58847424900); Li, Yongjian (56162279800); Zhang, Changgeng (55836915700)","58847424900; 56162279800; 55836915700","Wideband loss separation model of nanocrystalline materials considering microscopic magnetization mechanism","2024","AIP Advances","14","1","015231","","","","0","10.1063/9.0000643","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85183314445&doi=10.1063%2f9.0000643&partnerID=40&md5=cc2368bf57e91d42aefc073f373255f7","State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300401, China; Province-Ministry Joint Key Laboratory of EFEAR, Hebei University of Technology, Tianjin, 300401, China","Zhou J., State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300401, China, Province-Ministry Joint Key Laboratory of EFEAR, Hebei University of Technology, Tianjin, 300401, China; Li Y., State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300401, China, Province-Ministry Joint Key Laboratory of EFEAR, Hebei University of Technology, Tianjin, 300401, China; Zhang C., State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300401, China, Province-Ministry Joint Key Laboratory of EFEAR, Hebei University of Technology, Tianjin, 300401, China","The core loss directly determines the performance of high-frequency transformers. This paper presents an enhanced method for calculating core losses by integrating the LLG equation and Maxwell's diffusion equation. By the method, the losses caused by the rotation of the magnetic moment can be obtained. The loss attributed to domain wall displacement is derived from the total loss by subtracting losses due to magnetic moment rotation, further categorized into the hysteresis loss and the residual loss. The observation of the dynamic variation of nanocrystalline magnetic domains with applied excitation verifies the feasibility of the improved method. Finally, the causes of residual loss generation are also analyzed the model accuracy is verified by comparing the measured and modelled values and the traditional loss separation model. © 2024 Author(s).","","Magnetic cores; Magnetic domains; Magnetic moments; Magnetization; Maxwell equations; Nanocrystalline materials; Core loss; Diffusion equations; Domain wall displacement; High-frequency transformers; LLG equation; Loss separation; Magnetization mechanism; Performance; Separation model; Wide-band; Nanocrystals","","","","","Cultivate Foundation of Innovation Ability of Hebei Education Department for Postgraduates, (CXZZSS2024014); National Natural Science Foundation of China, NSFC, (51777055, 52130710)","This work was supported in part by the National Natural Science Foundation of China, (No. 52130710, 51777055) and the Cultivate Foundation of Innovation Ability of Hebei Education Department for Postgraduates (No. CXZZSS2024014). ","Mogorovic M., Modeling and design optimization of medium frequency transformers for medium-voltage high-power converters, EPFL, (2019); Feng C., Zhang Y., Chi Q., 2022 IEEE Industry Applications Society Annual Meeting (IAS), pp. 1-5, (2022); Matsumori H., Shimizu T., Kosaka T., Matsui N., Core loss calculation for power electronics converter excitation from a sinusoidal excited core loss data, AIP Advances, 10, 4, (2020); Syed A., Vakil G., Ram Kumar R.M., 2021 International Conference on Sustainable Energy and Future Electric Transportation (SEFET), pp. 1-5, (2021); Yue S., Li Y., Yang Q., Yu X., Zhang C., Comparative analysis of core loss calculation methods for magnetic materials under nonsinusoidal excitations, IEEE Transactions on Magnetics, 54, 11, (2018); Chen L., Yi Q., Ben T., Zhang Z., Wang Y., Parameter identification of Preisach model based on velocity-controlled particle swarm optimization method, AIP Advances, 11, 1, (2021); Chen L., Zhang Z., Ben T., Zhao H., Dynamic magnetic hysteresis modeling based on improved parametric magneto-dynamic model, IEEE Transactions on Applied Superconductivity, 32, 6, (2022); Chen Z., Yang X., Chen Y., Zheng H., Estimation of iron losses in Terfenol-D for variable DC-biased and AC excitation conditions, Journal of Applied Physics, 134, 11, (2023); Perigo E.A., Weidenfeller B., Kollar P., Fuzer J., Past, present, and future of soft magnetic composites, Applied Physics Reviews, 5, 3, (2018); Zhao H., Eldeeb H.H., Zhang Y., Zhang D., Zhan Y., Xu G., Mohammed O.A., An improved core loss model of ferromagnetic materials considering high-frequency and nonsinusoidal supply, IEEE Transactions on Industry Applications, 57, 4, pp. 4336-4346, (2021); Bin C., Lin L., Zhibin Z., Magnetic core losses under high-frequency typical non-sinusoidal voltage magnetization, Transactions of China Electrotechnical Society, 33, 8, (2018); Alatawneh N., Pillay P., The minor hysteresis loop under rotating magnetic fields in machine laminations, IEEE Transactions on Industry Applications, 50, 4, pp. 2544-2553, (2014); Zhao H., Ragusa C., Appino C., de la Barriere O., Wang Y., Fiorillo F., Energy losses in soft magnetic materials under symmetric and asymmetric induction waveforms, IEEE Transactions on Power Electronics, 34, 3, pp. 2655-2665, (2019)","Y. Li; State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300401, China; email: liyongjian@hebut.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85183314445" +"Amel'chenko M.D.; Grishin S.V.; Ogrin F.Y.; Nikitov S.A.","Amel'chenko, Maria D. (58758692400); Grishin, Sergei V. (7005849094); Ogrin, Feodor Yu. (57193655015); Nikitov, Sergei A. (7004556902)","58758692400; 7005849094; 57193655015; 7004556902","Micromagnetic simulation of ferromagnetic metamaterials with wire inclusions","2023","Physical Review B","108","22","224401","","","","2","10.1103/PhysRevB.108.224401","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85179499958&doi=10.1103%2fPhysRevB.108.224401&partnerID=40&md5=e0eac3c16ec8ab94ea0e1e16e212f437","Saratov State University, Saratov, 410012, Russian Federation; Department of Physics, University of Exeter, Exeter, EX4 4QL, United Kingdom; Kotelnikov Institute of Radioengineering and Electronics, Russian Academy of Science, Moscow, 125009, Russian Federation; MaxLLG Ltd., Exeter Science Park, Exeter, EX5 2FN, United Kingdom","Amel'chenko M.D., Saratov State University, Saratov, 410012, Russian Federation, MaxLLG Ltd., Exeter Science Park, Exeter, EX5 2FN, United Kingdom; Grishin S.V., Saratov State University, Saratov, 410012, Russian Federation; Ogrin F.Y., Department of Physics, University of Exeter, Exeter, EX4 4QL, United Kingdom; Nikitov S.A., Kotelnikov Institute of Radioengineering and Electronics, Russian Academy of Science, Moscow, 125009, Russian Federation","Left-handed (LH) metamaterials are generally structured materials possessing abnormal electromagnetic properties due to both negative permittivity and permeability. One of these properties is a backward wave (BW) propagation, in which the phase and group velocities are opposite to each other. Here we investigate the electrodynamic (dispersion and energy) characteristics of the BW existing in a magnetic LH metamaterial that is controlled by the external uniform magnetic field. Such a metamaterial is a host made from a μ-negative (ferromagnetic) nonconductive medium that contains a two-dimensional periodic structure of thin and isolated wires placed in the bias field directed either transversely or longitudinally to the electromagnetic wave propagation. A finite-difference time-domain-Landau-Lifshits-Gilbert (LLG) electromagnetic solver MaxLLG is used for the BW numerical simulations. This solver is based on the simultaneous usage of the Maxwell and LLG equations. By operating this software, the authors validate the existence of the BWs in the investigated LH metamaterial for two bias field orientations for various values of magnetic LH layer thickness and wire conductivity as well as for two connection types of wires with metallic planes that are placed on both sides of the metamaterial layer. © 2023 American Physical Society.","","Electromagnetic wave propagation; Ferromagnetic materials; Ferromagnetism; Finite difference time domain method; Maxwell equations; Wire; Backward-waves; Bias field; Electromagnetic properties; Ferromagnetics; Left handed metamaterial; Micromagnetic simulations; Negative permeability; Negative permittivity; Property; Structured materials; Metamaterials","","","","","EU H2020-MSCA-RISE, (823728, 823878); Russian Science Foundation, RSF, (19-79-20121)","The study was supported by the Russian Science Foundation Grant No. 19-79-20121, in the part of performing numerical simulations with the use of the MaxLLG software and building an analytical model. F.Y.O. acknowledges support by the EU H2020-MSCA-RISE projects TERASSE (Project No. 823878) and DiSeTCom (Project No. 823728). S.V.G. thanks Associate Prof. Michael I. Perchenko for useful discussions.","Veselago V. G., Electrodynamics of substances with simultaneously negative values (Equation presented) and (Equation presented), Sov. Phys. Usp, 10, (1968); Pendry J. B., Holden A. J., Stewart W. J., Youngs I., Extremely low frequency plasmons in metallic mesostructures, Phys. Rev. Lett, 76, (1996); Smith D. R., Padilla W. J., Vier D. C., Nemat-Nasser S. C., Schultz S., Composite medium with simultaneously negative permeability and permittivity, Phys. Rev. Lett, 84, (2000); Pendry J. B., Negative refraction makes a perfect lens, Phys. Rev. Lett, 85, (2000); Bespyatykh Y. I., Bugaev A. S., Dikshtein I. E., Surface polaritons in composite media with time dispersion of permittivity and permeability, Phys. Solid State, 43, (2001); Vashkovskii A. V., Lokk E., Negative refractive index for a surface magnetostatic wave propagating through the boundary between a ferrite and ferrite-insulator-metal media, Phys. Usp, 47, (2004); Dewar G., Minimization of losses in a structure having a negative index of refraction, New J. Phys, 7, (2005); He Y., He P., Yoon S. D., Parimic P. V., Rachford F. J., Harris V. G., Vittoria C., Tunable negative index metamaterial using yttrium iron garnet, J. Magn. Magn. Mater, 313, (2007); Zhao H., Zhou J., Zhao Q., Li B., Kang L., Bai Y., Magnetotunable left-handed material consisting of yttrium iron garnet slab and metallic wires, Appl. Phys. Lett, 91, (2007); Bi K., Zhou J., Zhao H., Liu X., Lan C., Tunable dual-band negative refractive index in ferrite-based metamaterials, Opt. Express, 21, (2013); Rachford F. J., Armstead D. N., Harris V. G., Vittoria C., Simulations of ferrite-dielectric-wire composite negative index materials, Phys. Rev. Lett, 99, (2007); Gurevich A. G., Melkov G. A., Magnetization Oscillations and Waves, (1996); Huang Y. J., Wen G. J., Li T. Q., Li J. L. W., Xie K., Design and characterization of tunable terahertz metamaterials with broad bandwidth and low loss, IEEE AWP Lett, 11, (2012); Grishin S. V., Amel'chenko M. D., Sharaevskii Y. P., Nikitov S. A., Double negative media based on antiferromagnetic metamaterials, Tech. Phys. Lett, 48, (2022); Amel'chenko M. D., Grishin S. V., Sharaevskii Y. P., Fast and slow electromagnetic waves in a longitudinally magnetized thin-film ferromagnetic metamaterial, Tech. Phys. Lett, 45, (2019); High Frequency Magnetics Software, (2019); Mikaelyan A. L., Theory and Practice of Microwave Ferrites, (1963); Landau L. D., Lifshitz E. M., Course of Theoretical Physic, Physical Kinetics, 10, (1981); Aziz M. M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, PIER B, 15, (2009); Taflove A., Hagness S. C., Computational Electrodynamics: The Finite-difference Time-domain Method, (2000); Morozova M. A., Romanenko D. V., Serdobintsev A. A., Matveev O. V., Sharaevskii Y. P., Nikitov S. A., Magnonic crystal-semiconductor heterostructure: Double electric and magnetic fields control of spin waves properties, J. Magn. Magn. Mater, 514, (2020)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85179499958" +"Nallan S.; Zhu J.-G.","Nallan, Shreyes (57219327328); Zhu, Jian-Gang (57226007941)","57219327328; 57226007941","Spin Hall Switching Enabled by Uniaxial In-Plane Magnetocrystalline Anisotropy","2023","IEEE Transactions on Magnetics","59","11","3401205","","","","1","10.1109/TMAG.2023.3286383","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85162639658&doi=10.1109%2fTMAG.2023.3286383&partnerID=40&md5=87e83d5c00845b7149c8d6f9758c189c","Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","Nallan S., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States; Zhu J.-G., Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, PA, United States","We present a new method for stabilization of magnetic devices: in-plane uniaxial magnetocrystalline anisotropy, achieved through epitaxial growth of a magnetic thin film on a single-crystal substrate. This paradigm enables the creation of in-plane spin orbit torque magnetic random access memory (SOT-MRAM) devices that function without external fields and exhibit the same scalability as perpendicular SOT-MRAM. Through theoretical derivations and numerical simulations based on the Landau-Lifshitz-Gilbert (LLG) equation with spin transfer torque, we show that switching of such devices can be optimized by varying the angle between the injected spin current and the crystalline easy axis, and contrast this angular dependence with the Stoner-Wohlfarth model. Furthermore, we demonstrate rich and complex magnetization dynamics in this system, including strong and tunable dependence on bulk and interfacial magnetoresistance and boundaries between stochastic and deterministic switching. Finally, we present a concept that couples our in-plane anisotropy layer with an out-of-plane ferromagnet to achieve out-of-plane field-free SOT-MRAM switching. We quantify regions of operation for this new device and link them to simulation results for the in-plane layer alone. © 1965-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnetocrystalline anisotropy; spin hall effect (SHE); spin orbit torque magnetic random access memory (SOT-MRAM)","Epitaxial growth; Film growth; Magnetic recording; Magnetization reversal; Magnetocrystalline anisotropy; MRAM devices; Single crystals; Spin Hall effect; Stochastic systems; External fields; Landau-Lifshitz-Gilbert equations; Magnetic random access memory; Magnetic switching; Out-of-plane; Perpendicular magnetic anisotropy; Single-crystal substrates; Spin orbit torque magnetic random access memory; Spin orbits; Theoretical derivations; Magnetic anisotropy","","","","","","","Liu L., Pai C.-F., Li Y., Tseng H.W., Ralph D.C., Buhrman R.A., Spin-torque switching with the giant spin Hall effect of tantalum, Science, 336, 6081, pp. 555-558, (2012); Shao Q., Et al., Roadmap of spin-orbit torques, IEEE Trans. Magn, 57, 7, pp. 1-39, (2021); Apalkov D., Khvalkovskiy A., Watts S., Krounbi M., Spin-transfer torque magnetic random access memory (STT-MRAM), ACM J. Emerg. Technol. Comput. Syst, 9, 2, pp. 1-35, (2013); Nallan S., Zhu J.-G., Achieving uniaxial in-plane magnetocrystalline anisotropy to enable scalable SOT-MRAM devices, Proc. IEEE Int. Conf. Magn. (INTERMAG), (2023); Xiao Y., Wang H., Fullerton E.E., Crystalline orientation-dependent spin Hall effect in epitaxial platinum, Frontiers Phys, 9, (2022); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, 1-2, pp. L1-L7, (1996); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Philos. Trans. Roy. Soc. A, Math., Phys. Eng. Sci, 240, 826, pp. 599-642, (1948); Worledge D.C., Theory of spin torque switching current for the double magnetic tunnel junction, IEEE Magn. Lett, 8, pp. 1-5, (2017); Sato N., Xue F., White R.M., Bi C., Wang S.X., Two-terminal spin-orbit torque magnetoresistive random access memory, Nature Electron, 1, 9, pp. 508-511, (2018); Sheng Y., Edmonds K.W., Ma X., Zheng H., Wang K., Adjustable current-induced magnetization switching utilizing interlayer exchange coupling, Adv. Electron. Mater, 4, 9, (2018)","S. Nallan; Carnegie Mellon University, Data Storage Systems Center, Pittsburgh, 15213, United States; email: shreyes@cmu.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85162639658" +"Chen J.; Li P.; Wang C.","Chen, Jingrun (57219146828); Li, Panchi (57211560785); Wang, Cheng (57192604518)","57219146828; 57211560785; 57192604518","Convergence Analysis of an Implicit Finite Difference Method for the Inertial Landau–Lifshitz–Gilbert Equation","2024","Journal of Scientific Computing","101","2","48","","","","0","10.1007/s10915-024-02690-3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85205956503&doi=10.1007%2fs10915-024-02690-3&partnerID=40&md5=1a21289ce14a0d1703ed24832fb9f257","School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Mathematics Department, University of Massachusetts, North Dartmouth, 02747, MA, United States","Chen J., School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China, Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; Li P., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Wang C., Mathematics Department, University of Massachusetts, North Dartmouth, 02747, MA, United States","The Landau–Lifshitz–Gilbert (LLG) equation is widely used to model the fast magnetization dynamics of ferromagnets. Recent experimental observations have revealed ultra-fast dynamics at the sub-picosecond timescale, and the inertial LLG equation is proposed to capture the ultra-fast behaviour of magnetization, in which a second temporal derivative of magnetization (inertial term) is introduced. The inertial LLG equation is therefore a mixed hyperbolic-parabolic type equation with degeneracy, which produces extra difficulties in numerical analysis. In this paper, we propose an implicit finite difference scheme based on the central difference in both time and space, and a fixed point iteration method to solve the nonlinear system. By a constructed solution with second order accuracy, we get a linear system and provide an unconditional convergence analysis in ℓ∞([0,T];Hh1(Ω)). We demonstrate that the proposed method is second order accurate in both time and space, a natural preservation of the magnetization length and the energy decaying. In the hyperbolic regime, significant nutation of magnetization at a shorter timescale are simulated by numerical simulations. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.","35K61; 65M06; 65M12; Convergence analysis; Implicit central difference scheme; Inertial Landau–Lifshitz–Gilbert equation; Second order accuracy","Convergence of numerical methods; Difference equations; Hyperbolic functions; Integral equations; Iterative methods; Magnetic moments; Nonlinear analysis; Nonlinear equations; 35k61; 65m06; 65m12; Central difference scheme; Convergence analysis; Implicit central difference scheme; Inertial landau–lifshitz–gilbert equation; Landau-Lifshitz-Gilbert equations; Second-order accuracy; Time-scales; Magnetization","","","","","China Scholarship Council, CSC, (202106920036)","This work is supported in part by the grant NSFC 11971021 (J. Chen), the program of China Scholarships Council No. 202106920036 (P. Li). ","Alouges F., A new finite element scheme for Landau–Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, 2, pp. 187-196, (2008); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau–Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci, 16, 2, pp. 299-316, (2006); Alouges F., Kritsikis E., Toussaint J., A convergent finite element approximation for Landau–Lifschitz–Gilbert equation, Phys. B: Condens. Matter, 407, 9, pp. 1345-1349, (2012); An R., Gao H., Sun W., Optimal error analysis of Euler and Crank-Nicolson projection finite difference schemes for Landau–Lifshitz equation, SIAM J. Numer. Anal, 59, 3, pp. 1639-1662, (2021); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz–Gilbert equation, SIAM J. Numer. Anal, 44, 4, pp. 1405-1419, (2006); Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Ultrafast spin dynamics in ferromagnetic nickel, Phys. Rev. Lett, 76, pp. 4250-4253, (1996); Bhattacharjee S., Nordstrom L., Fransson J., Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett, 108, (2012); Cai Y., Chen J., Wang C., Xie C., A second-order numerical method for Landau–Lifshitz–Gilbert equation with large damping parameters, J. Comput. Phys, 451, (2022); Cai Y., Chen J., Wang C., Xie C., Error analysis of a linear numerical scheme for the Landau–Lifshitz equation with large damping parameters, Math. Methods Apply. Sci, 46, pp. 18952-18974, (2023); Chen J., Wang C., Xie C., Convergence analysis of a second-order semi-implicit projection method for Landau–Lifshitz equation, Appl. Numer. Math, 168, pp. 55-74, (2021); Cimrak I., Error estimates for a semi-implicit numerical scheme solving the Landau–Lifshitz equation with an exchange field, IMA J. Numer. Anal, 25, 3, pp. 611-634, (2005); Cimrak I., A survey on the numerics and computations for the Landau–Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng, 15, pp. 277-309, (2008); Ciornei M.-C., Rubi J.M., Wegrowe J.-E., Magnetization dynamics in the inertial regime: nutation predicted at short time scales, Phys. Rev. B, 83, (2011); Wang X., Numerical methods for the Landau–Lifshitz equation, SIAM J. Numer. Anal, 38, 5, pp. 1647-1665, (2000); Fahnle M., Steiauf D., Illg C., Generalized Gilbert equation including inertial damping: derivation from an extended breathing Fermi surface model, Phys. Rev. B, 84, (2011); Gao H., Optimal error estimates of a linearized backward Euler FEM for the Landau–Lifshitz equation, SIAM J. Numer. Anal, 52, 5, pp. 2574-2593, (2014); Gilbert T., A Lagrangian formulation of gyromagnetic equation of the magnetization field, Phys. Rev, 100, pp. 1243-1255, (1955); Kammerer M., Weigand M., Curcic M., Noske M., Sproll M., Vansteenkiste A., Van Waeyenberge B., Stoll H., Woltersdorf G., Back C.H., Schuetz G., Magnetic vortex core reversal by excitation of spin waves, Nat. Commun, 2, (2011); Koopmans B., Malinowski G., Dalla Longa F., Steiauf D., Fahnle M., Roth T., Cinchetti M., Aeschlimann M., Explaining the paradoxical diversity of ultrafast laser-induced demagnetization, Nat. Mater, 9, pp. 259-265, (2010); Kritsikis E., Vaysset A., Buda-Prejbeanu L.D., Alouges F., Toussaint J.-C., Beyond first-order finite element schemes in micromagnetics, J. Comput. Phys, 256, pp. 357-366, (2014); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, 3, pp. 439-483, (2006); Landau L., Lifshitz E., On the theory of the dispersion of magetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Li P., Xie C., Du R., Chen J., Wang X., Two improved Gauss-Seidel projection methods for Landau–Lifshitz–Gilbert equation, J. Comput. Phys, 401, (2020); Li P., Yang L., Lan J., Du R., Chen J., A second-order semi-implicit method for the inertial Landau–Lifshitz–Gilbert equation, Numer. Math. Theor. Meth. Appl, 16, pp. 182-203, (2023); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo G., Azzerboni B., A numerical solution of the magnetization reversal modeling in a permalloy thin film using fifth order Runge–Kutta method with adaptive step size control, Phys. B: Condens. Matter, 403, 2, pp. 464-468, (2008); Samelson R., Temam R., Wang C., Wang S., Surface pressure poisson equation formulation of the primitive equations: numerical schemes, SIAM J. Numer. Anal, 41, pp. 1163-1194, (2003); Wang C., Liu J.-G., Convergence of gauge method for incompressible flow, Math. Comp, 69, pp. 1385-1407, (2000); Wang C., Liu J.-G., Johnston H., Analysis of a fourth order finite difference method for incompressible Boussinesq equation, Numer. Math, 97, pp. 555-594, (2004); Wang X., Garcia-Cervera C.J., A Gauss–Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, 1, pp. 357-372, (2001); Xie C., Garcia-Cervera C.J., Wang C., Zhou Z., Chen J., Second-order semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys, 404, (2020)","P. Li; School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; email: LiPanchi1994@163.com","","Springer","","","","","","08857474","","JSCOE","","English","J Sci Comput","Article","Final","","Scopus","2-s2.0-85205956503" +"Li L.; Wang Y.E.","Li, Li (59378516200); Wang, Yuanxun Ethan (57202387207)","59378516200; 57202387207","The FDTD Method for Hybrid Computations of the Maxwell and Linear LLG Equations","2024","IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)","","","","211","212","1","0","10.1109/AP-S/INC-USNC-URSI52054.2024.10687029","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85207053736&doi=10.1109%2fAP-S%2fINC-USNC-URSI52054.2024.10687029&partnerID=40&md5=3d3fc53a8225968d72acd08c528a31ab","The University of California at Los Angeles, Los Angeles, 90095, CA, United States","Li L., The University of California at Los Angeles, Los Angeles, 90095, CA, United States; Wang Y.E., The University of California at Los Angeles, Los Angeles, 90095, CA, United States","The FDTD method is utilized for computational-Multiphysics. The hybrid computations are proposed for the 3D component designs based on the ferromagnetic materials combined by electromagnetics and the magnetic dipole moment. The computations hire the Maxwell equations and the Landau-Lifshitz-Gilbert (LLG) equations for the computations of the electromagnetic and magnetic dipole moment values. The FDTD solver is implemented through the leap-frog processing and under the Courant-Friedrichs-Lewy condition. The simulation results are shown for the field decaying effects of the thin-film ferromagnetic materials. © 2024 IEEE.","","Critical current density (superconductivity); Electric dipole moments; Ferromagnetic materials; Liouville equation; Magnetic moments; Surface discharges; Thin films; Component design; Condition; Courant-Friedrichs-Lewy; Electromagnetics; Ferromagnetics; Hybrid computation; Landau-Lifshitz-Gilbert equations; Multi-physics; Thin films-ferromagnetic; Maxwell equations","","","","","Intelligence Advanced Research Projects Activity, IARPA","This work is supported by IARPA Equal-P program, the opinions expressed in this article are the authors' own and do not reflect the view of the United States government.","Gao Q., Ernest Fordham M., Gu W., Cui H., Ethan Wang Y., Design RF magnetic devices with linear and nonlinear equivalent circuit models, IEEE Microwave Magazine, 23, pp. 28-47, (2022); Yao Z., Umut Tok R., Itoh T., Ethan Wang Y., A multiscale unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics, IEEE Transactions on Microwave Theory and Techniques, 66, pp. 2683-2696, (2018); Li L., Eibert T., Radial angular singularity cancellation transformations derived by variable separation, IEEE Transactions on Antennas and Propagation, 64, pp. 189-200, (2016); Li L., Wang K., Eibert T., A projection height independent adaptive radial-angular-R2 transformation for singular integrals, IEEE Transactions on Antennas and Propagation, 62, pp. 5381-5386, (2014); Gu W., Luong K., Yao Z., Cui H., Wang Y.E., Ferromagnetic Resonance-Enhanced Electrically Small Antenna, IEEE Transactions on Antennas and Propagation, 69, pp. 8304-8314, (2021)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (APS); Italian National Committee (ITNC); The Institute of Electrical and Electronics Engineers; US National Committee (USNC) of the International Union of Radio Science (URSI)","2024 IEEE International Symposium on Antennas and Propagation and INC/USNCURSI Radio Science Meeting, AP-S/INC-USNC-URSI 2024","14 July 2024 through 19 July 2024","Florence","203041","15223965","979-835036990-8","IAPSB","","English","IEEE Antennas Propag Soc AP S Int Symp","Conference paper","Final","","Scopus","2-s2.0-85207053736" +"Tung C.-T.; Dasgupta A.; Agarwal H.; Salahuddin S.; Hu C.","Tung, Chien-Ting (57205381088); Dasgupta, Avirup (56389226300); Agarwal, Harshit (53866052200); Salahuddin, Sayeef (8544299000); Hu, Chenming (58264295500)","57205381088; 56389226300; 53866052200; 8544299000; 58264295500","A Compact Model of Perpendicular Spin-Transfer-Torque Magnetic Tunnel Junction","2024","IEEE Transactions on Electron Devices","71","1","","57","61","4","2","10.1109/TED.2023.3313997","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85173057852&doi=10.1109%2fTED.2023.3313997&partnerID=40&md5=3007f03ee031603a022b9bf378943d9c","University of California at Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, 94720, CA, United States; IIT-Roorkee, Department of Electronics and Communication Engineering, Roorkee, 247667, India; IIT-Jodhpur, Department of Electrical Engineering, Jodhpur, 342030, India","Tung C.-T., University of California at Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, 94720, CA, United States; Dasgupta A., IIT-Roorkee, Department of Electronics and Communication Engineering, Roorkee, 247667, India; Agarwal H., IIT-Jodhpur, Department of Electrical Engineering, Jodhpur, 342030, India; Salahuddin S., University of California at Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, 94720, CA, United States; Hu C., University of California at Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, 94720, CA, United States","We present a new compact model of a perpendicular spin-transfer-torque (STT) magnetic tunnel junction (MTJ). Previous studies on STT-MTJs have either focused on solving the Landau-Lifshitz-Gilbert (LLG) equation or utilizing critical current-based macro models. However, the LLG approaches are too complex for large circuit simulations, while the macro models fail to capture the underlying magnetization physics. In this work, we propose a semiphysical and computationally efficient compact model that accurately represents the time-dependent magnet moment and resistance. To validate our model, we compare it with various experimental data and LLG-based STT-MTJ model. The model demonstrates geometry dependence and temperature dependence. Furthermore, we develop a continuous switching probability model to effectively track the probabilities of states under arbitrary waveforms. © 1963-2012 IEEE.","Compact model; Landau-Lifshitz-Gilbert (LLG) equation; magnetic tunnel junction (MTJ); SPICE; spin transfer torque (STT); spintronics; switching probability; temperature dependence; write error rate (WER)","Integrated circuits; Magnetic circuits; Magnetic devices; SPICE; Temperature distribution; Tunnel junctions; 'spice'; Compact model; Computational modelling; Error rate; Fitting; Integrated circuit modeling; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Magnetic tunneling; Resistance; Spin transfer torque; Switching probability; Temperature dependence; Write error rate; Timing circuits","","","","","","","Julliere M., Tunneling between ferromagnetic films, Phys. Lett. A, 54, 3, pp. 225-226, (1975); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, 1, pp. 1-7, (1996); Huai Y., Albert F., Nguyen P., Pakala M., Valet T., Observation of spin-transfer switching in deep submicron-sized and low-resistance magnetic tunnel junctions, Appl. Phys. Lett, 84, 16, pp. 3118-3120, (2004); Butler W.H., Et al., Switching distributions for perpendicular spin-torque devices within the macrospin approximation, IEEE Trans. Magn, 48, 12, pp. 4684-4700, (2012); Khvalkovskiy A.V., Et al., Erratum: Basic principles of STT-MRAM cell operation in memory arrays, J. Phys. D, Appl. Phys, 46, 13, (2013); Koch R.H., Katine J.A., Sun J.Z., Time-resolved reversal of spin-transfer switching in a nanomagnet, Phys. Rev. Lett, 92, 8, (2004); Zhang Y., Et al., Electrical modeling of stochastic spin transfer torque writing in magnetic tunnel junctions for memory and logic applications, IEEE Trans. Magn, 49, 7, pp. 4375-4378, (2013); Fong X., Choday S.H., Georgios P., Augustine C., Roy K., Purdue nanoelectronics research laboratory magnetic tunnel junction model, nanoHUB, (2014); Roy A.S., Sarkar A., Mudanai S.P., Compact modeling of magnetic tunneling junctions, IEEE Trans. Electron Devices, 63, 2, pp. 652-658, (2016); Kammerer J.-B., Madec M., Hebrard L., Compact modeling of a magnetic tunnel junction-Part I: Dynamic magnetization model, IEEE Trans. Electron Devices, 57, 6, pp. 1408-1415, (2010); Gaul N.S., Et al., A physics based MTJ compact model for state-of-theart and emerging STT-MRAM failure analysis and yield enhancement, Proc. IEEE Int. Memory Workshop (IMW), pp. 1-4, (2022); Madec M., Kammerer J.-B., Hebrard L., Compact modeling of a magnetic tunnel junction-Part II: Tunneling current model, IEEE Trans. Electron Devices, 57, 6, pp. 1416-1424, (2010); Harms J.D., Ebrahimi F., Yao X., Wang J.-P., SPICE macromodel of spin-torque-transfer-operated magnetic tunnel junctions, IEEE Trans. Electron Devices, 57, 6, pp. 1425-1430, (2010); Lim H., Lee S., Shin H., A survey on the modeling of magnetic tunnel junctions for circuit simulation, Act. Passive Electron. Compon, 2016, pp. 1-12, (2016); Xu Z., Yang C., Mao M., Sutaria K.B., Chakrabarti C., Cao Y., Compact modeling of STT-MTJ devices, Solid-State Electron, 102, pp. 76-81, (2014); Vincent A.F., Locatelli N., Klein J.-O., Zhao W.S., Galdin-Retailleau S., Querlioz D., Analytical macrospin modeling of the stochastic switching time of spin-transfer torque devices, IEEE Trans. Electron Devices, 62, 1, pp. 164-170, (2015); Pahwa G., Et al., Compact modeling of emerging IC devices for technology-design co-development, IEDM Tech. Dig., (2022); Wang Y., Cai H., Naviner L.A.B., Zhang Y., Klein J.O., Zhao W.S., Compact thermal modeling of spin transfer torque magnetic tunnel junction, Microelectron. Rel, 55, 9-10, pp. 1649-1653, (2015); Drewello V., Schmalhorst J., Thomas A., Reiss G., Evidence for strong magnon contribution to the TMR temperature dependence in MgO based tunnel junctions, Phys. Rev. B, Condens. Matter, 77, 1, (2008); Zhang L., Et al., Addressing the thermal issues of STT-MRAM from compact modeling to design techniques, IEEE Trans. Nanotechnol, 17, 2, pp. 345-352, (2018); Li J., Ndai P., Goel A., Salahuddin S., Roy K., Design paradigm for robust spin-torque transfer magnetic RAM (STT MRAM) from circuit/architecture perspective, IEEE Trans. Very Large Scale Integr. (VLSI) Syst, 18, 12, pp. 1710-1723, (2010); Ishikawa T., Et al., Spin-dependent tunneling characteristics of fully epitaxial magnetic tunneling junctions with a full-Heusler alloy Co2MnSi thin film and a MgO tunnel barrier, Appl. Phys. Lett, 89, 19, (2006); Zhang Y., Et al., Compact modeling of perpendicularanisotropy CoFeB/MgO magnetic tunnel junctions, IEEE Trans. Electron Devices, 59, 3, pp. 819-826, (2012); Alzate J.G., Et al., Temperature dependence of the voltage-controlled perpendicular anisotropy in nanoscale MgO|CoFeB|Ta magnetic tunnel junctions, Appl. Phys. Lett, 104, 11, (2014); Yuan L., Liou S.H., Wang D., Temperature dependence of magnetoresistance in magnetic tunnel junctions with different free layer structures, Phys. Rev. B, Condens. Matter, 73, 13, (2006); Chun K.C., Zhao H., Harms J.D., Kim T.-H., Wang J.-P., Kim C.H., A scaling roadmap and performance evaluation of inplane and perpendicular MTJ based STT-MRAMs for high-density cache memory, IEEE J. Solid-State Circuits, 48, 2, pp. 598-610, (2013); Wu L., Et al., Pinhole defect characterization and fault modeling for STT-MRAM testing, Proc. IEEE Eur. Test Symp. (ETS), pp. 1-6, (2019); Carboni R., Et al., A physics-based compact model of stochastic switching in spin-transfer torque magnetic memory, IEEE Trans. Electron Devices, 66, 10, pp. 4176-4182, (2019); Lin C.J., Et al., 45 nm low power CMOS logic compatible embedded STT MRAM utilizing a reverse-connection 1T/1MTJ cell, IEDM Tech. Dig., pp. 1-4, (2009)","C.-T. Tung; University of California at Berkeley, Department of Electrical Engineering and Computer Sciences, Berkeley, 94720, United States; email: cttung@berkeley.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-85173057852" +"Wang K.-X.; Su L.; Tong L.-L.","Wang, Ke-Xin (58653806900); Su, Li (57201978921); Tong, Liang-Le (57881062600)","58653806900; 57201978921; 57881062600","Analysis of spin-orbit torque magnetic tunnel junction model without external magnetic field assistance based on antiferromagnetism; [基于反铁磁的无外场辅助自旋轨道矩磁隧道结模型分析]","2023","Wuli Xuebao/Acta Physica Sinica","72","19","198504","","","","0","10.7498/aps.72.20230901","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85174399186&doi=10.7498%2faps.72.20230901&partnerID=40&md5=26707da66e1f4c91d4c2afd066337e62","Information Engineering College, Capital Normal University, Beijing, 100048, China","Wang K.-X., Information Engineering College, Capital Normal University, Beijing, 100048, China; Su L., Information Engineering College, Capital Normal University, Beijing, 100048, China; Tong L.-L., Information Engineering College, Capital Normal University, Beijing, 100048, China","The effect of spin-orbit torque (SOT) provides a new method of implementing ultra-low power spintronic devices. The in-plane exchange bias (EB) field in antiferromagnetic material can effectively assist SOT magnetization switching. Meanwhile, the utilization of voltage-controlled magnetic anisotropy (VCMA) can effectively reduce the switching barrier. Taking advantage of the EB and VCMA effect, it is possible to realize SOT magnetic tunnel junctions without external field assistance. In this work, a spin-orbit torque magnetic tunnel junction model composed of antiferromagnetic/ferromagnetism/oxides without external magnetic field is developed by solving the modified Landau-Lifshitz-Gilbert (LLG) modular equation, and its magnetization dynamics is analyzed and studied. The effective fields in the model include the demagnetization field, thermal noise field, perpendicular magnetic anisotropy field with VCMA effect, and exchange bias field. Taking IrMn/CoFeB/MgO material system for example, the factors affecting the precession of magnetization are investigated, such as the effect of the exchange bias field, the VCMA effect and the mechanism of SOT field-like torque. Considering the practical applications, the effect of the deviation of the fabrication process of magnetic tunnel junctions is also analyzed. The simulation results demonstrate that the combined effect of with HEB VCMA effect can greatly reduce the critical ISOT, thus assisting and realizing the complete field-free magnetization reversal; the SOT field-like torque plays a dominant role in realizing the magnetization reversal, and by adjusting the ratio of the SOT field-like torque to the damping-like torque, field free switching can be realized in the device at the ps grade; and the MTJ can realize effective switching when the deviation of oxide thickness γtf ≤ 10% or the deviation of free layer thickness γtox ≤ 13% . Spin-orbit torque devices based on the antiferromagnetic without external magnetic field will provide highly promising solutions for a new-generation ultra-low power, ultra-high speed, and ultra-high integration devices and circuits. © 2023 Chinese Physical Society.","exchange bias; process deviation; spin-orbit torque magnetic tunnel junction; voltage-controlled magnetic anisotropy","Antiferromagnetism; Bias voltage; Demagnetization; Low power electronics; Magnetic anisotropy; Magnetic fields; Magnetization reversal; Tunnel junctions; Anisotropy effect; Exchange bias; Exchange-bias fields; External magnetic field; Magnetic tunnel junction; Process deviations; Spin orbits; Spin-orbit torque magnetic tunnel junction; Voltage-controled magnetic anisotropy; Voltage-controlled; Torque","","","","","Department of Beijing Municipal Committee, China, (2018000020124G124); Science and Technology Plan General Project of Beijing, China, (KM202110028010); Natural Science Foundation of Beijing Municipality, (4194073)","* Project supported by the Natural Science Foundation of Beijing, China (Grant No. 4194073), the Science and Technology Plan General Project of Beijing, China (Grant No. KM202110028010), the Outstanding Talent Cultivation Funding for Young Backbone Individual Project and Organization Department of Beijing Municipal Committee, China (Grant No. 2018000020124G124). † Corresponding author. 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Su; Information Engineering College, Capital Normal University, Beijing, 100048, China; email: li.su@cnu.edu.cn","","Institute of Physics, Chinese Academy of Sciences","","","","","","10003290","","WLHPA","","Chinese","Wuli Xuebao","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85174399186" +"Zhan J.; Yang L.; Du R.; Cui Z.","Zhan, Jiajun (57222157503); Yang, Lei (59043156600); Du, Rui (56763448500); Cui, Zixuan (59203777200)","57222157503; 59043156600; 56763448500; 59203777200","Towards Preserving Geometric Properties of Landau-Lifshitz-Gilbert Equation Using Multistep Methods","2024","Communications in Computational Physics","35","5","","1327","1351","24","1","10.4208/cicp.OA-2023-0201","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85191425589&doi=10.4208%2fcicp.OA-2023-0201&partnerID=40&md5=0dbbe664fb940cbfec7e356e876df1b1","School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao, 999078, Macao; School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China","Zhan J., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao, 999078, Macao; Yang L., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao, 999078, Macao; Du R., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; Cui Z., School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao, 999078, Macao","In this paper, we investigate two fundamental geometric properties of the Landau-Lifshitz-Gilbert (LLG) equation, namely the preservation of magnetization magnitude and the Lyapunov structure, by using multistep methods. While the majority of current multistep methods for solving the LLG equation are based on two-step discrete schemes, our research specifically focuses on investigating more general multistep methods. Our proposed methods encompass a range of multistep discrete schemes that allow for achieving any desired order of accuracy in the temporal domain. In this highly general framework, we demonstrate that the magnitude of magnetization is preserved within an error of order (p+2) in time when employing a (p+1)th-order multistep discrete scheme. Additionally, the Lyapunov structure is preserved with a first-order error of temporal step size. Finally, some numerical experiments are presented to validate the accuracy of the proposed multistep discrete schemes. ©2024 Global-Science Press.","computational micromagnetics; Geometric property; Landau-Lifshitz-Gilbert equation; multistep methods","","","","","","Science and Technology Development Fund, STDF; Macau, (0031/2022/A1); MUST, (FRG 22-021-FI); NSFC, (12271360, 11501399)","J. Zhan, L. Yang, and Z. Cui are supported by the Science and Technology Development Fund, Macau SAR (File No. 0031/2022/A1) and MUST Faculty Research Grants (FRG 22-021-FI). R. Du is supported by NSFC (Grant No. 12271360 and No. 11501399).","Bottauscio O., Manzin A., Efficiency of the geometric integration of Landau-Lifshitz-Gilbert equation based on Cayley transform, IEEE Trans. Magn, 47, 5, pp. 1154-1157, (2011); Cai Y., Chen J., Wang C., Xie C., A second-order numerical method for Landau-Lifshitz-Gilbert equation with large damping parameters, J. Comput. Phys, 451, (2022); Chen Y., Sun Y., Tang Y., Energy-preserving numerical methods for Landau–Lifshitz equation, J. Phys. A: Math. Theor, 44, (2011); Donahue M.J., Porter D.G., OOMMF User’s Guide, Version 1.0, (1999); d'Aquino M., Capuano F., Coppola G., Serpico C., Mayergoyz I. D., Efficient adaptive pseudo-symplectic numerical integration techniques for Landau-Lifshitz dynamics, AIP Adv, 8, (2018); d'Aquino M., Capuano F., Coppola G., Serpico C., Mayergoyz I. D., Pseudo-symplectic numerical schemes for Landau-Lifshitz dynamics, Physica B, 549, pp. 98-101, (2018); d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau–Lifshitz–Gilbert equation based on the mid-point rule, J. Comput. Phys, 209, pp. 730-753, (2005); d'Aquino M., Serpico C., Miano G., Mayergoyz I. D., Bertotti G., Numerical integration of Landau–Lifshitz–Gilbert equation based on the midpoint rule, J. Appl. Phys, 97, (2005); Wang X., Numerical methods for the Landau-Lifshitz equation, SIAM J. Numer. 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B, 27, 11, pp. 6401-6416, (2022); Li P., Yang L., Lan J., Du R., Chen J., A second-order semi-implicit method for the inertial Landau-Lifshitz-Gilbert equation, Numer. Math. Theor. Meth. Appl, 16, 1, pp. 182-203, (2023); National Institute of Standardsand Technology; Rahim A., Ragusa C., Jan B., Khan O., A mixed mid-point Runge-Kutta like scheme for the integration of Landau-Lifshitz equation, J. Appl. Phys, 115, (2014); Serpico C., Mayergoyz I., Bertotti G., Analysis of eddy currents with Landau-Lifshitz equation as a constitutive relation, IEEE Trans. Magn, 37, 5, pp. 3546-3549, (2001); Serpico C., Mayergoyz I. D., Bertotti G., Numerical technique for integration of the Landau–Lifshitz equation, J. Appl. Phys, 89, 11, pp. 6991-6993, (2001); Shepherd D., Miles J., Heil M., Mihajlovic M., An adaptive step implicit midpoint rule for the time integration of Newton’s linearisations of non-linear problems with applications in micromagnetics, J. Sci. Comput, 80, pp. 1058-1082, (2019); Spargo A. W., Ridley P. H. W., Roberts G. W., Geometric integration of the Gilbert equation, J. Appl. Phys, 93, 10, pp. 6805-6807, (2003); Stoer J., Bulirsch R., Introduction to Numerical Analysis, (2002); Van de Wiele B., Olyslager F., Dupre L., Fast numerical three-dimensional scheme for the simulation of hysteresis in ferromagnetic grains, J. Appl. Phys, 101, (2007); Van de Wiele B., Olyslager F., Dupre L., Fast semianalytical time integration schemes for the Landau–Lifshitz equation, IEEE Trans. Magn, 43, 6, pp. 2917-2919, (2007); Wang X., Garcia-Cervera C. J., A Gauss–Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, pp. 357-372, (2001); Xie C., Garcia-Cervera C. J., Wang C., Zhou Z., Chen J., Second-order semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys, 404, (2020); Yang L., Chen J., Hu G., A framework of the finite element solution of the Landau-Lifshitz-Gilbert equation on tetrahedral meshes, J. Comput. Phys, 431, (2021); Yang W., Wang D., Yang L., A stable numerical method for space fractional Landau–Lifshitz equations, Appl. Math. Lett, 61, pp. 149-155, (2016); Zhao G., An R., Optimal error analysis of partially-updated projection FEM scheme for the Landau-Lifshitz equation based on the Crank-Nicolson discretization, J. Appl. Anal. Comput, 11, 6, pp. 3115-3132, (2021)","L. Yang; School of Computer Science and Engineering, Faculty of Innovation Engineering, Macau University of Science and Technology, Macao, 999078, Macao; email: leiyang@must.edu.mo","","Global Science Press","","","","","","18152406","","","","English","Commun. Comput. Phys.","Article","Final","","Scopus","2-s2.0-85191425589" +"Fast K.R.; Losby J.E.; Hajisalem G.; Barclay P.E.; Freeman M.R.","Fast, K.R. (57221498292); Losby, J.E. (9733996900); Hajisalem, G. (26535986400); Barclay, P.E. (7006758609); Freeman, M.R. (7402429572)","57221498292; 9733996900; 26535986400; 7006758609; 7402429572","Einstein-de Haas torque as a discrete spectroscopic probe allows nanomechanical measurement of a magnetic resonance","2024","Physical Review B","109","6","064404","","","","1","10.1103/PhysRevB.109.064404","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85184668402&doi=10.1103%2fPhysRevB.109.064404&partnerID=40&md5=4453d22638d8dfaa1eaca1a0faa07c7a","Department of Physics, University of Alberta, Edmonton, T6G 2E1, AB, Canada; Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada; Department of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, AB, Canada","Fast K.R., Department of Physics, University of Alberta, Edmonton, T6G 2E1, AB, Canada, Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada; Losby J.E., Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada, Department of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, AB, Canada; Hajisalem G., Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada, Department of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, AB, Canada; Barclay P.E., Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada, Department of Physics and Astronomy, University of Calgary, Calgary, T2N 1N4, AB, Canada; Freeman M.R., Department of Physics, University of Alberta, Edmonton, T6G 2E1, AB, Canada, Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 2M9, AB, Canada","The Einstein-de Haas (EdH) effect is a fundamental, mechanical consequence of any temporal change of magnetism in an object. EdH torque results from conserving the object's total angular momentum: The angular momenta of all the specimen's magnetic moments, together with its mechanical angular momentum. Although the EdH effect is usually small and difficult to observe, it increases in magnitude with detection frequency. We explore the frequency dependence of EdH torque for a thin film permalloy microstructure by employing a ladder of flexural beam modes (with five distinct resonance frequencies spanning from 3 to 208 MHz) within a nanocavity optomechanical torque sensor via magnetic hysteresis curves measured at mechanical resonances. At low dc fields, the gyrotropic resonance of a magnetic vortex spin texture overlaps the 208 MHz mechanical mode. The massive EdH mechanical torques arising from this coresonance yield a fingerprint of vortex core pinning and depinning in the sample. The experimental results are discussed in relation to mechanical torques predicted from both macrospin (at high dc magnetic field) and finite-difference solutions to the Landau-Lifshitz-Gilbert (LLG) equation. A global fit of the LLG solutions to the frequency-dependent data reveals a statistically significant discrepancy between the experimentally observed and simulated torque phase behaviours at spin-texture transitions that can be reduced through the addition of a time constant to the conversion between magnetic cross-product torque and mechanical torque, constrained by experiment to be in the range of 0.5-4 ns. © 2024 American Physical Society.","","Iron alloys; Magnetic moments; Magnetic resonance; Nickel alloys; Textures; Torque; Vortex flow; Detection frequency; Frequencies dependence; Measurements of; Mechanical; Mechanical torque; Nanomechanical measurements; Spectroscopic probes; Spin textures; Temporal change; Thin-films; Angular momentum","","","","","Natural Sciences and Engineering Research Council of Canada, NSERC, (RGPIN-2021-02762); Natural Sciences and Engineering Research Council of Canada, NSERC; National Research Council Canada, NRC; University of Alberta, UofA; Canada Foundation for Innovation, CFI, (34028); Canada Foundation for Innovation, CFI; Canada Research Chairs, (230377); Canada Research Chairs","The authors gratefully acknowledge support from the Natural Sciences and Engineering Research Council, Canada (No. RGPIN-2021-02762), the Canada Foundation for Innovation (No. 34028), the Canada Research Chairs (No. 230377), the National Research Council (Canada), and the University of Alberta. 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(22968144400)","58597012300; 57222288607; 57221317240; 59157888400; 22968144400","Thermal effect on microwave pulse-driven magnetization switching of stoner particle","2024","Physica Scripta","99","1","015947","","","","1","10.1088/1402-4896/ad1706","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85181444185&doi=10.1088%2f1402-4896%2fad1706&partnerID=40&md5=bbb9c03114dbe219fa12c26478b3f78a","Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, No. 28 Xianning West Road, Shaanxi, Xi'an, 710049, China; Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Department of Physics, Colorado State University, Fort Collins, 80523, CO, United States","Chowdhury S., Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Akanda M.A.S., Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Pikul M.A.J., Department of Physics, Colorado State University, Fort Collins, 80523, CO, United States; Islam M.T., Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, No. 28 Xianning West Road, Shaanxi, Xi'an, 710049, China, Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Min T., Center for Spintronics and Quantum Systems, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, No. 28 Xianning West Road, Shaanxi, Xi'an, 710049, China","We investigate the cosine-chirped microwave pulse (cosine CMP)-driven magnetization switching of a nanoparticle or stoner particle at a finite temperature in the framework of the stochastic Landau-Lifshitz-Gilbert equation. Numerical results reveal that the ultrafast and efficient magnetization switching is robust even at room temperature, and hence we estimate the maximal temperature at which the magnetization switching is still valid. The maximal temperature increases with the enlargement (by increasing cross-sectional area) of the nanoparticle/stoner particle volume to a certain value, and afterward, the maximal temperature decreases with the further increment of the nanoparticle size. Initially, the shape anisotropy (approximated by the easy-plane) coefficient does not become dominant although the stoner particle volume increases, which plays a role in increasing thermal stability (maximal temperature), and later the shape anisotropy field becomes dominant, which opposes the uniaxial anisotropy, i.e., reduces the energy barrier, which reduces the maximal temperature. For smaller volumes, the parameters of cosine CMP show a decreasing trend with temperature. The initial frequency requirement significantly decreases with shape anisotropy. Therefore, these findings might be useful to realize cosine CMP-driven fast and energy-efficient magnetization switching in device applications. © 2023 © 2023 IOP Publishing Ltd.","energy barrier; magnetic nanoparticles/stoner particles; magnetization switching; shape anisotropy; stochastic LLG equation","Anisotropy; Energy efficiency; Magnetization; Nanomagnetics; Nanoparticles; Stochastic systems; Chirped microwave pulse; Finite temperatures; LLG equation; Magnetic nanoparticle/stone particle; Magnetization switching; Microwave pulse; Particle volume; Shape anisotropy; Stochastic LLG equation; Stochastics; Energy barriers","","","","","BANBEIS, (SD2019972); National Natural Science Foundation of China, NSFC, (12 350 410 352); National Natural Science Foundation of China, NSFC; Ministry of Education, Government of the People's Republic of Bangladesh, MoE; Khulna University, KU, (KU/RC-04/2000-158); Khulna University, KU; National Key Research and Development Program of China, NKRDPC, (2021YFA1202200); National Key Research and Development Program of China, NKRDPC","This work acknowledges the support of the National Natural Science Foundation of China (Grant No. 12 350 410 352), the National Key R and D Program of China (Grant No. 2021YFA1202200), the Khulna University Research Cell (Grant No. KU/RC-04/2000-158), Khulna, Bangladesh, and the Ministry of Education (BANBEIS, Grant No. SD2019972). 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Rev.B, 82, (2010)","","","Institute of Physics","","","","","","00318949","","PHSTB","","English","Phys Scr","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85181444185" +"Klausen K.O.; Ingvarsson S.","Klausen, Kristjan Ottar (57219528362); Ingvarsson, Snorri (20734369800)","57219528362; 20734369800","Spinor Formulation of the Landau–Lifshitz–Gilbert Equation With Geometric Algebra","2025","IEEE Transactions on Magnetics","61","1","1300205","","","","0","10.1109/TMAG.2024.3509214","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85210949310&doi=10.1109%2fTMAG.2024.3509214&partnerID=40&md5=5b9ef3eab4a648a380da2fea305e194e","Science Institute, University of Iceland, Reykjavik, 107, Iceland","Klausen K.O., Science Institute, University of Iceland, Reykjavik, 107, Iceland; Ingvarsson S., Science Institute, University of Iceland, Reykjavik, 107, Iceland","The Landau–Lifshitz–Gilbert (LLG) equation for magnetization dynamics is recast into spinor form using the real-valued Clifford algebra (geometric algebra) of three-space. We show how the undamped case can be explicitly solved to obtain componentwise solutions, with clear geometrical meaning. Generalizations of the approach to include damping are formulated. The implications of the axial property of the magnetization vector are briefly discussed. © 1965-2012 IEEE.","Algebra; damping; magnetization; micromagnetics","Algebra; Geometry; Clifford algebra; Component wise; Generalisation; Geometric Algebra; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetization vector; Property; Spinors; Magnetization","","","","","Icelandic Centre for Research, RANNIS, (239623, 228951); Icelandic Centre for Research, RANNIS","This work was supported by funding from the Icelandic Research Fund, grants no. 239623 and 228951.","Hirohata A., Et al., Review on spintronics: Principles and device applications, J. Magn. Magn. Mater., 509, (2020); Sierra J.F., Fabian J., Kawakami R.K., Roche S., Valenzuela S.O., Van der Waals heterostructures for spintronics and opto-spintronics, Nature Nanotechnol, 16, 8, pp. 856-868, (2021); Rajput P.J., Bhandari S.U., Wadhwa G., A review on—Spintronics an emerging technology, Silicon, 14, 15, pp. 9195-9210, (2022); Muhlbauer S., Et al., Skyrmion lattice in a chiral magnet, Science, 323, 5916, pp. 915-919, (2009); Aguado R., Majorana quasiparticles in condensed matter, La Rivista del Nuovo Cimento, 40, pp. 523-593, (2017); Marrows C.H., Zeissler K., Perspective on skyrmion spintronics, Appl. Phys. Lett., 119, 25, (2021); Sarma S.D., Freedman M., Nayak C., Majorana zero modes and topological quantum computation, NPJ Quantum Inf, 1, 1, (2015); Landau L.D., Lifstatz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. 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Matter, 35, 2, (2022); Floerchinger S., Real Clifford algebras and their spinors for relativistic fermions, Universe, 7, 6, (2021); Garling D.J.H., Clifford Algebras: An Introduction, (2011); Lounesto P., Clifford Algebras and Spinors, (2001); Porteous I.R., Clifford Algebras and the Classical Groups (Cambridge Studies in Advanced Mathematics), (1995); Doran C., Lasenby A., Geometric Algebra for Physicists, (2003); Hestenes D., Sobczyk G., Clifford Algebra to Geometric Calculus: A Unified Language for Mathematics and Physics, 5, (2012); Macdonald A., Linear and Geometric Algebra (Geometric Algebra & Calculus), (2010); Doran C., Hestenes D., Sommen F., Van Acker N., Lie groups as spin groups, J. Math. Phys., 34, 8, pp. 3642-3669, (1993); Lawson H.B., Michelsohn M.L., Spin Geometry (PMS-38) (Princeton Mathematical Series), 38, (2016); Hestenes D., Space-Time Algebra, (2015); Francis M.R., Kosowsky A., The construction of spinors in geometric algebra, Ann. 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Sci., 47, 3, pp. 1331-1361, (2022)","K.O. Klausen; Science Institute, University of Iceland, Reykjavik, 107, Iceland; email: kristjank@hi.is","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85210949310" +"Zhang J.; Yu W.; Chen X.; Xiao J.","Zhang, Jiabin (57899637100); Yu, Weichao (57190667472); Chen, Xiheng (57899447800); Xiao, Jiang (23111925000)","57899637100; 57190667472; 57899447800; 23111925000","A frequency-domain micromagnetic simulation module based on COMSOL Multiphysics","2023","AIP Advances","13","5","055108","","","","13","10.1063/5.0143262","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85157973242&doi=10.1063%2f5.0143262&partnerID=40&md5=9332bba313d09e49c87b743f7a83b1b6","Department of Physics, State Key Laboratory of Surface Physics, Fudan University, Shanghai, 200433, China; Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, 201210, China; Shanghai Qi Zhi Institute, Shanghai, 200232, China; Shanghai Research Center for Quantum Sciences, Shanghai, 201315, China","Zhang J., Department of Physics, State Key Laboratory of Surface Physics, Fudan University, Shanghai, 200433, China; Yu W., Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, 201210, China; Chen X., Department of Physics, State Key Laboratory of Surface Physics, Fudan University, Shanghai, 200433, China; Xiao J., Department of Physics, State Key Laboratory of Surface Physics, Fudan University, Shanghai, 200433, China, Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, 201210, China, Shanghai Qi Zhi Institute, Shanghai, 200232, China, Shanghai Research Center for Quantum Sciences, Shanghai, 201315, China","Micromagnetic simulation is a numerical method to solve the Landau-Lifshitz-Gilbert (LLG) equation for magnetic dynamics. Most of the mainstream micromagnetic simulation packages, including the object oriented micromagnetic framework and MuMax3, perform simulation in the time domain. Here, utilizing the frequency domain simulation capability of COMSOL Multiphysics, we developed a COMSOL-based micromagnetic simulation module that solves the LLG equation in the frequency domain, which runs much faster and more accurate than time-domain simulations. Frequency-domain simulation is ideal for finding spin wave eigenmodes and the corresponding dispersions. We verify the validity of the module using three examples in the absence of dipolar field, and the inclusion of the dipolar field can be incorporated by combining this module with the alternating current/direct current module within COMSOL. © 2023 Author(s).","","Frequency domain analysis; Numerical methods; Spin waves; Time domain analysis; Dipolar fields; Frequency domain simulation; Frequency domains; Landau-Lifshitz-Gilbert equations; Magnetic dynamics; Micromagnetic simulations; Module-based; Multi-physics; Simulation modules; Simulation packages; Multiphysics","","","","","National Natural Science Foundation of China, NSFC, (12204107); Science and Technology Commission of Shanghai Municipality, STCSM, (2019SHZDZX01, 20JC1415900, 21JC1406200, 21PJ1401500)","This work was supported by the Science and Technology Commission of Shanghai Municipality (Grant Nos. 20JC1415900, 21PJ1401500, and 21JC1406200), the Shanghai Municipal Science and Technology Major Project (Grant No. 2019SHZDZX01), and the National Natural Science Foundation of China (Grant No. 12204107). 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Phys., 133, (2023); d'Aquino M.; Rychly J., Klos J.W., Spin wave surface states in 1D planar magnonic crystals, J. Phys. D: Appl. Phys., 50, (2017); Sobucki K., Smigaj W., Rychly J., Krawczyk M., Gruszecki P., Resonant subwavelength control of the phase of spin waves reflected from a Gires-Tournois interferometer, Sci. Rep., 11, (2021); Liu C.; Dzyaloshinsky I., A thermodynamic theory of ‘weak’ ferromagnetism of antiferromagnetics, J. Phys. Chem. Solids, 4, pp. 241-255, (1958); Moriya T., Anisotropic superexchange interaction and weak ferromagnetism, Phys. Rev., 120, (1960); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, (1996); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, 62, (2000); Xiao J., Zangwill A., Stiles M.D., Macrospin models of spin transfer dynamics, Phys. Rev. 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Nanotechnol., 11, pp. 432-436, (2016); Albisetti E., Petti D., Sala G., Silvani R., Tacchi S., Finizio S., Wintz S., Calo A., Zheng X., Raabe J., Riedo E., Bertacco R., Nanoscale spin-wave circuits based on engineered reconfigurable spin-textures, Commun. Phys., 1, (2018); Sluka V., Schneider T., Gallardo R.A., Kakay A., Weigand M., Warnatz T., Mattheis R., Roldan-Molina A., Landeros P., Tiberkevich V., Slavin A., Schutz G., Erbe A., Deac A., Lindner J., Raabe J., Fassbender J., Wintz S., Emission and propagation of 1D and 2D spin waves with nanoscale wavelengths in anisotropic spin textures, Nat. Nanotechnol., 14, pp. 328-333, (2019); Schutte C., Garst M., Magnon-skyrmion scattering in chiral magnets, Phys. Rev. B, 90, (2014); Kim J.-V., Garcia-Sanchez F., Sampaio J., Moreau-Luchaire C., Cros V., Fert A., Breathing modes of confined skyrmions in ultrathin magnetic dots, Phys. Rev. B, 90, (2014); Zhang V.L., Hou C.G., Di K., Lim H.S., Ng S.C., Pollard S.D., Yang H., Kuok M.H., Eigenmodes of Néel skyrmions in ultrathin magnetic films, AIP Adv., 7, (2017); Kim J., Yang J., Cho Y.-J., Kim B., Kim S.-K., Coupled breathing modes in one-dimensional skyrmion lattices, J. Appl. Phys., 123, (2018)","W. Yu; Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China; email: wcyu@fudan.edu.cn; J. Xiao; Department of Physics, State Key Laboratory of Surface Physics, Fudan University, Shanghai, 200433, China; email: xiaojiang@fudan.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85157973242" +"Reyes-Osorio F.; Nikolić B.K.","Reyes-Osorio, Felipe (57215814010); Nikolić, Branislav K. (7006055333)","57215814010; 7006055333","Gilbert damping in metallic ferromagnets from Schwinger-Keldysh field theory: Intrinsically nonlocal, nonuniform, and made anisotropic by spin-orbit coupling","2024","Physical Review B","109","2","024413","","","","4","10.1103/PhysRevB.109.024413","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85182406005&doi=10.1103%2fPhysRevB.109.024413&partnerID=40&md5=f8fc8d3a34441f45858c4432fcb2ce54","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Reyes-Osorio F., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Understanding the origin of damping mechanisms in the magnetization dynamics of metallic ferromagnets is a fundamental problem for nonequilibrium many-body physics of systems in which quantum conduction electrons interact with localized spins assumed to be governed by the classical Landau-Lifshitz-Gilbert (LLG) equation. It is also of critical importance for applications because damping affects energy consumption and the speed of spintronic and magnonic devices. Since the 1970s, a variety of linear-response and scattering theory approaches have been developed to produce widely used formulas for computation of the spatially independent Gilbert scalar parameter as the magnitude of the Gilbert damping term in the LLG equation. The Schwinger-Keldysh field theory (SKFT), largely unexploited for this purpose, offers additional possibilities, such as to rigorously derive an extended LLG equation by integrating quantum electrons out. Here we derive such an equation whose Gilbert damping for metallic ferromagnets is nonlocal, i.e., dependent on all localized spins at a given time, and nonuniform, even if all localized spins are collinear and spin-orbit coupling (SOC) is absent. This is in sharp contrast to standard lore, in which nonlocal damping is considered to emerge only if localized spins are noncollinear - for such situations, direct comparison using the example of a magnetic domain wall shows that SKFT-derived nonlocal damping is an order of magnitude larger than the previously considered one. Switching on SOC makes such nonlocal damping anisotropic, in contrast to standard lore, in which SOC is usually necessary to obtain a nonzero Gilbert damping scalar parameter. Our analytical formulas, with their nonlocality being more prominent in low spatial dimensions, are fully corroborated by numerically exact quantum-classical simulations. © 2024 American Physical Society. ","","Computation theory; Damping; Domain walls; Energy utilization; Ferromagnetic materials; Ferromagnetism; Magnetic domains; Damping mechanisms; Field theory; Gilbert damping; Landau-Lifshitz-Gilbert equations; Localized spin; Magnetization dynamics; Metallic ferromagnets; Nonlocal; Scalar parameters; Spin-orbit couplings; Anisotropy","","","","","National Science Foundation, NSF, (ECCS 1922689)","This work was supported by the U.S. National Science Foundation (NSF), Grant No. ECCS 1922689.","Landau L. D., Lifshitz E. M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, (1935); Berkov D. V., Miltat J., Spin-torque driven magnetization dynamics: Micromagnetic modeling, J. Magn. Magn. Mater, 320, (2008); Kim S.-K., Micromagnetic computer simulations of spin waves in nanometre-scale patterned magnetic elements, J. Phys. D, 43, (2010); Evans R., Fan W., Chureemart P., Ostler T., Ellis M. 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B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85182406005" +"Marfoua B.; Hong J.","Marfoua, Brahim (57189389224); Hong, Jisang (7404114034)","57189389224; 7404114034","Highly efficient spin-orbit torque generation in bilayer WTe2/Fe3GaTe2 heterostructure","2024","Materials Today Physics","42","","101378","","","","1","10.1016/j.mtphys.2024.101378","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85186335836&doi=10.1016%2fj.mtphys.2024.101378&partnerID=40&md5=0690d260ffd51eb40d55fa765c967ae6","Department of Physics, Pukyong National University, Busan, 48513, South Korea","Marfoua B., Department of Physics, Pukyong National University, Busan, 48513, South Korea; Hong J., Department of Physics, Pukyong National University, Busan, 48513, South Korea","The spin-orbit torque (SOT) phenomenon is crucial for advancing spintronics. Therefore, we explore the SOT efficiency in the WTe2/Fe3GaTe2 heterostructure. The WTe2/Fe3GaTe2 heterostructure has a ferromagnetic ground state with a perpendicular magnetic anisotropy. Through the Metropolis Monte Carlo simulations, we find that the WTe2/Fe3GaTe2 heterostructure has a Curie temperature of 345 K. We also calculate the temperature-dependent coercive field HC(T) via the extended Landau-Lifshitz-Gilbert (LLG) equation, and the estimated coercive field is 0.32 T at 300 K. From the electrical and spin Hall conductivity of the WTe2 layer, we obtain a giant spin Hall angle of ∼4 is obtained at a low chemical potential. Besides, the WTe2/Fe3GaTe2 heterostructure exhibits a critical current density of ∼7.40 × 104 A/cm2 at 300 K. This value is superior to that found in most previously reported materials. Finally, we achieve the switching power consumption of approximately 1.80 × 1015 W/m3 at 300 K, and this is comparable to or even lower than the values found in other bulk type or thick thickness SOT materials. Due to this highly efficient SOT performance, the ultrathin WTe2/Fe3GaTe2 heterostructure may offer a promising avenue for advanced room temperature spintronic applications with implications for both fundamental research and technological advancements. © 2024","2D WTe2/Fe3GaTe2 heterostructure; Critical current density; Spin Hall angle; Spin-orbit torque; Switching power consumption","Coercive force; Electric power utilization; Energy efficiency; Ground state; Intelligent systems; Magnetic anisotropy; Spintronics; Tellurium compounds; 2d WTe2/fe3gate2 heterostructure; Bi-layer; Coercive field; Critical current density; Spin hall angle; Spin orbits; Spin-orbit torque; Switching power; Switching power consumption; Torque generation; Monte Carlo methods","","","","","Association Française contre les Myopathies, AFM; Ministry of Science, ICT and Future Planning, MSIP, (2022R1A2C1004440, KSC-2023-CRE-0190); National Research Foundation of Korea, NRF","Funding text 1: We first examine the monolayer structures of 1T′-WTe2 (WTe2) and Fe3GaTe2. The WTe2 monolayer exhibits a distorted orthorhombic 1T’ structure with a doubling of periodicity in one direction relative to the other. The monolayer of Fe3GaTe2 has a hexagonal structure within the P6m2 group. Following thorough geometry optimization, we obtain the lattice parameters of a = 6.30 Å and b = 3.50 Å for the WTe2 monolayer and a = b = 4.04 Å for the Fe3GaTe2 monolayer. Fig. 1 (a)-(b) shows top and side views of the optimized WTe2 and Fe3GaTe2 monolayer structures. These optimized lattice parameters are consistent with prior experimental reports [20,21,28]. Then, we investigate the magnetic ground state of the Fe3GaTe2 monolayer by calculating the total energy difference between the antiferromagnetic (AFM) and ferromagnetic (FM) states (ΔEAFM-EFM). The Fe3GaTe2 monolayer has an FM ground state with an energy difference of ΔEex = 272 meV per unit cell. The total magnetic moment is 5.87 μB per unit cell. The Fe atom in the central sublayer (Fecentral) has a local magnetic moment of 1.4 μB, while those in the top and bottom sublayers (Fetop and Febottom) have magnetic moments of 2.3 μB. Besides, we also find that the Fe3GaTe2 monolayer has a perpendicular magnetic anisotropy energy of 0.59 meV per unit cell. These results agree with a previous report [28]. We further investigate the electronic band structure including the spin-orbit coupling (SOC) effect. Fig. 1(c)–(d) displays the SOC band structures of the free standing WTe2 and Fe3GaTe2 monolayer structures. In the WTe2 monolayer, we apply the Hubbard U value of 5 eV to reproduce the experimentally measured band gap of 55 meV [20]. In Supporting Information (SI) Fig. S1 and Table S1, we present the SOC band structure of WTe2 with varying U values (U = 0, 2, 3, 4, 5, 5.5 eV).This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (2022R1A2C1004440) and by the Supercomputing Center/Korea Institute of Science and Technology Information with supercomputing resources including technical support (KSC-2023-CRE-0190).; Funding text 2: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) ( 2022R1A2C1004440 ) and by the Supercomputing Center/Korea Institute of Science and Technology Information with supercomputing resources including technical support ( KSC-2023-CRE-0190 ). 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Commun., 14, (2023); Shi S., Liang S., Zhu Z., Cai K., Pollard S.D., Wang Y., Wang J., Wang Q., He P., Yu J., All-electric magnetization switching and Dzyaloshinskii–Moriya interaction in WTe2/ferromagnet heterostructures, Nat. Nanotechnol., 14, pp. 945-949, (2019); Xu H., Wei J., Zhou H., Feng J., Xu T., Du H., He C., Huang Y., Zhang J., Liu Y., High spin hall conductivity in large‐area type‐II Dirac semimetal PtTe2, Adv. Mater., 32, (2020); Hu C.-Y., Chiu Y.-F., Tsai C.-C., Huang C.-C., Chen K.-H., Peng C.-W., Lee C.-M., Song M.-Y., Huang Y.-L., Lin S.-J., Toward 100% spin–orbit torque efficiency with high spin–orbital Hall conductivity Pt–Cr alloys, ACS Appl. Electron. Mater., 4, pp. 1099-1108, (2022); Ostwal V., Shen T., Appenzeller J., Efficient spin‐orbit torque switching of the semiconducting van der Waals ferromagnet Cr2Ge2Te6, Adv. Mater., 32, (2020); Jiang M., Asahara H., Sato S., Ohya S., Tanaka M., Suppression of the field-like torque for efficient magnetization switching in a spin–orbit ferromagnet, Nat. Electron., 3, pp. 751-756, (2020); Wang Y., Yang H., Spin–orbit torques based on topological materials, Acc. Mater. Res., 3, pp. 1061-1072, (2022)","J. Hong; Department of Physics, Pukyong National University, Busan, 48513, South Korea; email: hongj@pknu.ac.kr","","Elsevier Ltd","","","","","","25425293","","","","English","Mat. Today Phy.","Article","Final","","Scopus","2-s2.0-85186335836" +"Chen B.J.; Hou Y.; Gan C.K.; Zeng M.","Chen, BingJin (36118704100); Hou, Yubo (57218455787); Gan, Chee Kwan (14026531500); Zeng, Minggang (35492095200)","36118704100; 57218455787; 14026531500; 35492095200","Micromagnetic realization of energy-based models using stochastic magnetic tunnel junctions","2023","Applied Physics A: Materials Science and Processing","129","9","655","","","","0","10.1007/s00339-023-06931-4","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85169546239&doi=10.1007%2fs00339-023-06931-4&partnerID=40&md5=02cc38042784d122aca7f811dbda8ec6","Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Singapore; Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #21-01 Connexis, Singapore, 138632, Singapore","Chen B.J., Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Singapore; Hou Y., Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #21-01 Connexis, Singapore, 138632, Singapore; Gan C.K., Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Singapore; Zeng M., Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #21-01 Connexis, Singapore, 138632, Singapore","Energy-based models (EBMs) can bridge physics, machine learning, and statistics. EBMs provide a unified and powerful platform to describe, learn, and optimize complex systems. In this paper, we propose a neuromorphic implementation of EBMs using a network of stochastic magnetic tunnel junctions (MTJs) that can perform energy minimization and solve optimization problems. Our implementation builds on the Object Oriented MicroMagnetic Framework (OOMMF). We derive the different energy terms and map them to the micromagnetic Landau-Lifshitz-Gilbert (LLG) equation. We then develop a C + + module for EBMs which integrates seamlessly with OOMMF. We demonstrate our implementation on a full set of logic gates using stochastic MTJs networks. Our method offers several advantages, including fast modeling of EBMs with spintronic devices and design insights for stochastic MTJ-based neuromorphic circuits. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.","Energy-based models; Micromagnetic simulations; Stochastic magnetic tunnel junctions","C++ (programming language); Magnetic devices; Stochastic models; Tunnel junctions; Energy-based models; Learn+; Machine-learning; Magnetic tunnel junction; Micromagnetic simulations; Micromagnetics; Neuromorphic; Object oriented; Stochastic magnetic tunnel junction; Stochastics; Stochastic systems","","","","","Agency for Science, Technology and Research, A*STAR, (C210812054); Agency for Science, Technology and Research, A*STAR","This work is supported by Agency for Science, Technology and Research (A*STAR) under Career Development Fund (Project No. C210812054). ","Zhirnov V.V., Cavin R.K., Hutchby J.A., Bourianoff G.I., Proc. IEEE, 91, pp. 1934-1939, (2003); Yang J.J., Strukov D.B., Stewart D.R., Nat. Nanotechnol., 8, pp. 13-24, (2013); Camsari K.Y., Torunbalci M.M., Borders W.A., Ohno H., Fukami S., Phys. Rev. Appl., 15, (2021); Kobayashi K., Borders W.A., Kanai S., Hayakawa K., Ohno H., Fukami S., Appl. Phys. Lett., 119, (2021); Kobayashi K., Hayakawa K., Igarashi J., Borders W.A., Kanai S., Ohno H., Fukami S., Phys. Rev. Appl., 18, (2022); Yang L., Wang J.-P., In: 2017 IEEE Int. Electron Devices Meet, (2017); Daniels M.W., Madhavan A., Talatchian P., Mizrahi A., Stiles M.D., Phys. Rev. Appl., 13, (2020); Wang Y., Zhang Y., Deng E.Y., Klein J.O., Naviner L.A.B., Zhao W.S., Microelectron. Reliab., 54, pp. 1774-1778, (2014); Borders W.A., Pervaiz A.Z., Fukami S., Camsari K.Y., Ohno H., Datta S., Nature, 573, pp. 390-393, (2019); Kaiser J., Borders W.A., Camsari K.Y., Fukami S., Ohno H., Datta S., Phys. Rev. Appl., 17, (2022); Kaiser J., Datta S., Appl. Phys. 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Appl., 12, (2019); Chowdhury S., Datta S., Camsari K.Y., 2019 IEEE Int. Electron Devices Meet., (2019); Scellier B., Bengio Y., Front. Comput. Neurosci., 11, pp. 1-13, (2017)","B.J. Chen; Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), Singapore, 1 Fusionopolis Way, #16-16 Connexis, 138632, Singapore; email: Chen_BingJin@ihpc.a-star.edu.sg; M. Zeng; Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (A*STAR), Singapore, 1 Fusionopolis Way, #21-01 Connexis, 138632, Singapore; email: zeng_minggang@i2r.a-star.edu.sg","","Springer Science and Business Media Deutschland GmbH","","","","","","09478396","","APAMF","","English","Appl Phys A","Article","Final","","Scopus","2-s2.0-85169546239" +"Rothos V.M.; Mylonas I.K.; Bountis T.","Rothos, V.M. (6602556662); Mylonas, I.K. (57076094800); Bountis, T. (7003276524)","6602556662; 57076094800; 7003276524","Dissipative soliton dynamics of the Landau–Lifshitz–Gilbert equation","2023","Theoretical and Mathematical Physics(Russian Federation)","215","2","","622","635","13","1","10.1134/S0040577923050033","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85160604634&doi=10.1134%2fS0040577923050033&partnerID=40&md5=5886e850abd210a1408b23f1e1418bf1","School of Mechanical Engineering, University of Thessaloniki, Thessaloniki, Greece; Center of Integrable Systems, Demidov Yaroslavl State University, Yaroslavl, Russian Federation","Rothos V.M., School of Mechanical Engineering, University of Thessaloniki, Thessaloniki, Greece; Mylonas I.K., School of Mechanical Engineering, University of Thessaloniki, Thessaloniki, Greece; Bountis T., Center of Integrable Systems, Demidov Yaroslavl State University, Yaroslavl, Russian Federation","Abstract: We study ferromagnetic dissipative systems described by the isotropic LLG equation, from the standpoint of their spatially localized dynamical excitations. In particular, we focus on dissipative soliton solutions of a nonlocal NLS equation to which the LLG equation is transformed and use Melnikov’s theory to prove the existence of these solutions for sufficiently small dissipation. Next, we employ pseudospectral and PINN (physics-informed neural network) numerical techniques of machine learning to demonstrate the validity of our analytic results. Such localized structures have been detected experimentally in magnetic systems and observed in nano-oscillators, while dissipative magnetic droplet solitons have also been found theoretically and experimentally. © 2023, Pleiades Publishing, Ltd.","dissipative soliton dynamics; ferromagnetic dissipative system; LLG equation; NLS equation","","","","","","Ministry of Education and Science of the Republic of Kazakhstan; Russian Science Foundation, RSF, (21-71-30011, AP08856381)","T. Bountis acknowledges that his work on Sections 2, 3.1 and 3.2 of this paper was supported by the Russian Science Foundation project No. 21-71-30011. T. Bountis also acknowledges partial support for Section 3.3 by the grant No. AP08856381 of the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan, for the project of the Institute of Mathematics and Mathematical Modeling MES RK, Almaty, Kazakhstan. ","Lakshmanan M., Ruijgrok T.W., Thompson C.J., On the dynamics of continuum spin systems, Phys. A, 84, pp. 577-590, (1976); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-164, (1935); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Mattis D.C., The Theory of Magnetism I: Statics and Dynamics, 17, (1988); Stiles M.D., Miltat J., Spin-transfer torque and dynamics, Spin Dynamics in Confined Magnetic Structures III, 101, pp. 225-308, (2006); Lakshmanan M., The fascinating world of the Landau–Lifshitz–Gilbert equation: an overview, Philos. Trans. Roy. Soc. London Ser. A, 369, pp. 1280-1300, (2011); Descalzi O., Clerc M., Residori S., Localized States in Physics: Solitons and Patterns, (2011); Ahsan Z., Jayaprakash K.R., Evolution of a primary pulse in the granular dimers mounted on a linear elastic foundation: An analytical and numerical study, Phys. Rev. E, 94, (2016); Krolikowski W., Bang O., Nikolov N.I., Neshev D., Wyller J., Rasmussen J.J., Edmundson D., Modulational instability, solitons and beam propagation in spatially nonlocal nonlinear media, J. Opt. B: Quantum Semiclass. Opt., 6, pp. S288-S294, (2004); Slavin A.N., Tiberkevich V.S., Spin wave mode excited by spin-polarized current in a magnetic nanocontact is a standing self-localized wave bullet, Phys. Rev. Lett., 95, (2005); Hoefer M.A., Silva T.J., Keller M.W., Theory for a dissipative droplet soliton excited by a spin torque nanocontact, Phys. Rev. B, 82, (2010); Mohseni S.M., Sani S.R., Persson J., Et al., Spin torque-generated magnetic droplet solitons, Science, 339, pp. 1295-1298, (2013); Barashenkov I.V., Woodford S.R., Zemlyanaya E.V., Interactions of parametrically driven dark solitons. I. Néel–Néel and Bloch–Bloch interactions, Phys. Rev. E, 75, (2007); Besse V., Leblond H., Mihalache D., Malomed B.A., Pattern formation by kicked solitons in the two-dimensional Ginzburg–Landau medium with a transverse grating, Phys. Rev. E, 87, (2013); Lan Y., Li Y.C., Chaotic spin dynamics of a long nanomagnet driven by a current, Nonlinearity, 21, pp. 2801-2823, (2008); Daniel M., Lakshmanan M., Perturbation of solitons in the classical continuum isotropic Heisenberg spin system, Phys. A, 120, pp. 125-152, (1983); Wiggins S., Introduction to Applied Nonlinear Dynamical Systems and Chaos, 2, (2005); Gruendler J., The existence of homoclinic orbits and the method of Melnikov for systems, SIAM J. Math. Anal., 16, pp. 907-931, (1985); Yamashita M., Melnikov vector in higher dimensions, Nonlinear Anal. Theory Methods Appl., 18, pp. 657-670, (1992); Chow S.-N., Yamashita M., Geometry of the Melnikov vector, Math. Sci. Eng., 185, pp. 79-148, (1992); Rothos V.M., Bountis T.C., Mel’nikov analysis of phase space transport in a N-degree- of- freedom Hamiltonian system, Nonlinear Anal. Theory Methods Appl., 30, pp. 1365-1374, (1997); Yang J., Nonlinear Waves in Integrable and Nonintegrable Systems, 16, (2010); Raissi M., Perdikaris P., Karniadakis G.E., Physics-informed neural networks: a deep learning framework for solving forward and inverse problems involving nonlinear partial differential equations, J. Comput. Phys., 378, pp. 686-707, (2019); Rothos V.M., Vakakis A.F., Dynamic interactions of traveling waves propagating in a linear chain with local essentially nonlinear attachment, Wave Motion, 46, pp. 174-188, (2009); Palmer K.J., Exponential dichotomy and transversal homoclinic orbits, J. Differ. Equ., 55, pp. 225-256, (1984); Tsilifis P., Kevrekidis P.G., Rothos V.M., Cubic-quintic long-range interactions with double well potentials, J. Phys. A: Math. Theor., 47, (2014)","T. Bountis; Center of Integrable Systems, Demidov Yaroslavl State University, Yaroslavl, Russian Federation; email: tassosbountis@gmail.com","","Pleiades Publishing","","","","","","00405779","","","","English","Theor. Math. Phys.","Article","Final","","Scopus","2-s2.0-85160604634" +"Deng G.; Huang W.; Wang X.; Lu Y.; Yang Z.; Wang D.","Deng, Guangjian (57192893392); Huang, Wenhua (36063926100); Wang, Xiangyu (58747231800); Lu, Yanlei (36070644300); Yang, Zhiqiang (55716554800); Wang, Dunhui (7407077329)","57192893392; 36063926100; 58747231800; 36070644300; 55716554800; 7407077329","Numerical Simulation Method of Gyromagnetic Nonlinear Transmission Lines Based on Coupled Solution of Maxwell and LLG Equations","2023","IEEE Transactions on Plasma Science","51","9","","2632","2640","8","0","10.1109/TPS.2023.3309660","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85171573905&doi=10.1109%2fTPS.2023.3309660&partnerID=40&md5=7950a0a137271a96cca0a78abe715b6d","Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; Nanjing University, Natl. Lab. of Solid State Microstructures, Jiangsu Key Lab. for Nanotechnology, Collab. Innov. Ctr. of Adv. Microstructures, Nanjing, 210093, China","Deng G., Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China, Nanjing University, Natl. Lab. of Solid State Microstructures, Jiangsu Key Lab. for Nanotechnology, Collab. Innov. Ctr. of Adv. Microstructures, Nanjing, 210093, China; Huang W., Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; Wang X., Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; Lu Y., Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; Yang Z., Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; Wang D., Nanjing University, Natl. Lab. of Solid State Microstructures, Jiangsu Key Lab. for Nanotechnology, Collab. Innov. Ctr. of Adv. Microstructures, Nanjing, 210093, China","Recently, gyromagnetic nonlinear transmission line (GNLTL) technology has been commonly focused on and developed rapidly as a new type of solid-state wide-spectrum high-power microwave (HPM) generation method. However, because of the lack of an efficient simulation method, its investigation and design basically rely on experiment which increases the cost and complexity. Under this situation, a simulation method based on coupled solutions of Maxwell and Landau-Lifshitz-Gilbert (LLG) equations is proposed. It can realize 2-D/3-D simulation of GNLTLs. The results of this simulation method agree well with COMSOL Multiphysics software under an uncommonly weakly nonlinear situation. This verified the validity of this method to some extent. Finally, experiments are conducted to be directly contrasted with and further verify the simulation method. © 1973-2012 IEEE.","Coupled solution; gyromagnetic nonlinear transmission lines (GNTLs); high power microwave (HPM); simulation method","Computer software; Electric lines; Electric power transmission; Maxwell equations; Nonlinear equations; Numerical methods; Transient analysis; Coupled solution; Gyromagnetic nonlinear transmission line; Gyromagnetism; High power; High power microwave; High voltage techniques; Nonlinear transmission lines; Power microwave; Power transmission lines; Simulation method; Magnetic moments","","","","","","","Bragg J.-W.B., Dickens J.C., Neuber A.A., Ferrimagnetic nonlinear transmission lines as high-power microwave sources, IEEE Trans. Plasma Sci., 41, 1, pp. 232-237, (2013); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., Gyromagnetic RF source for interdisciplinary research, Rev. Sci. Instrum., 88, 2, (2017); Ulmaskulov M.R., Shunailov S.A., Sharypov K.A., Yalandin M.I., Multistage converter of high-voltage subnanosecond pulses based on nonlinear transmission lines, J. Appl. Phys., 126, 8, (2019); Rangel E.G.L., Rossi J.O., Barroso J.J., Yamasaki F.S., Schamiloglu E., Practical constraints on nonlinear transmission lines for RF generation, IEEE Trans. Plasma Sci., 47, 1, pp. 1000-1016, (2019); Gubanov V.P., Gunin A.V., Koval'chuk O.B., Kutenkov V.O., Romanchenko I.V., Rostov V.V., Effective transformation of the energy of high-voltage pulses into high-frequency oscillations using a saturated-ferrite-loaded transmission line, Tech. Phys. Lett., 35, 7, pp. 626-628, (2009); Romanchenko I.V., Rostov V.V., Gubanov V.P., Stepchenko A.S., Gunin A.V., Kurkan I.K., Repetitive sub-gigawatt RF source based on gyromagnetic nonlinear transmission line, Rev. Sci. Instrum., 83, 7, (2012); Bragg J.-W.-B., Dickens J.C., Neuber A.A., Material selection considerations for coaxial, ferrimagnetic-based nonlinear transmission lines, J. Appl. Phys., 113, 6, (2013); Rostov V.V., Bykov N.M., Bykov D.N., Klimov A.I., Kovalchuk O.B., Romanchenko I.V., Generation of subgigawatt RF pulses in nonlinear transmission lines, IEEE Trans. Plasma Sci., 38, 10, pp. 2681-2685, (2010); Reale D.V., Parson J.M., Neuber A.A., Dickens J.C., Mankowski J.J., Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources, Rev. Sci. Instrum., 87, 3, (2016); Bragg J.-W.-B., Sullivan W.W., Mauch D., Neuber A.A., Dickens J.C., All solid-state high power microwave source with high repetition frequency, Rev. Sci. Instrum., 84, 5, (2013); Ulmaskulov M.R., Et al., High repetition rate multi-channel source of high-power RF-modulated pulses, Rev. Sci. Instrum., 86, 7, (2015); Ulmaskulov M.R., Et al., Four-channel generator of 8-GHz radiation based on gyromagnetic non-linear transmitting lines, Rev. Sci. Instrum., 90, 6, (2019); Romanchenko I.V., Et al., Four channel high power RF source with beam steering based on gyromagnetic nonlinear transmission lines, Rev. Sci. Instrum., 88, 5, (2017); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, J. Appl. Phys., 117, 21, (2015); Johnson J.M., Et al., Characteristics of a four element gyromagnetic nonlinear transmission line array high power microwave source, Rev. Sci. Instrum., 87, 5, (2016); Ulmaskulov M.R., Shunailov S.A., Microwave generation modes of ferrite nonlinear transmission lines up to 20 GHz, J. Appl. Phys., 130, 23; Reale D.V., Coaxial ferrimagnetic based gyromagnetic nonlinear transmission lines as compact high power microwave sources, (2013); Dolan J.E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, J. Phys. D: Appl. Phys., 32, 15, pp. 1826-1831, (1999); Dolan J.E., Bolton H.R., Shock front development in ferrite-loaded coaxial lines with axial bias, IEE Proc., Sci., Meas. Technol., 147, 5, pp. 237-242, (2000); Cui Y., Meng J., Huang L., Yuan Y., Wang H., Zhu D., Operation analysis of the wideband high-power microwave sources based on the gyromagnetic nonlinear transmission lines, Rev. Sci. Instrum., 92, 3; Yamasaki F.S., Schamiloglu E., Rossi J.O., Barroso J.J., Simulation studies of distributed nonlinear gyromagnetic lines based on LC lumped model, IEEE Trans. Plasma Sci., 44, 10, pp. 2232-2239, (2016); Greco A.F.G., Et al., Analysis of the sharpening effect in gyromagnetic nonlinear transmission lines using the unidimensional form of the Landau–Lifshitz–Gilbert equation, Rev. Sci. Instrum., 93, 6; Rossi J.O., Silva Neto L.P., Yamasaki F.S., Barroso J.J., State of the art of nonlinear transmission lines for applications in high power microwaves, Proc. IMOC, pp. 1-5, (2013); Rossi J.O., Silva L.P., Barroso J.J., Yamasaki F.S., Schamiloglu E., Overview of RF generation using nonlinear transmission lines, Proc. PPC, pp. 1-6, (2015); Fairbanks A.J., Darr A.M., Garner A.L., A review of nonlinear transmission line system design, IEEE Access, 8, pp. 148606-148621, (2020); Rahman M., Wu K., Theory and practice of multidimensional nonlinear transmission line, Proc. IWS, pp. 1-3, (2021); Gilbert T.L., Classics in magnetics a phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Denner A.K., Experiments on temporal variable step BDF2 algorithms, (2014); Skeel R.D., The second-order backward differentiation formula is unconditionally zero-stable, Appl. Numer. Math., 5, 1-2, pp. 145-149, (1989); Ahn J.-W., Karelin S.Y., Kwon H.-O., Magda I.I., Sinitsin V.G., Exciting high frequency oscillations in a coaxial transmission line with a magnetized ferrite, J. Magn., 20, 4, pp. 460-465, (2015); Karelin S.Y., Krasovitsky V.B., Magda I.I., Mukhin V.S., Sinitsin V.G., RF oscillations in a coaxial transmission line with a saturated ferrite: 2-D simulation and experiment, Proc. 8th UWBUSIS, pp. 60-63, (2016); Karelin S.Y., FDTD analysis of nonlinear magnetized ferrites: Simulation of oscillation forming in coaxial line with ferrite, Telecommun. Radio Eng., 76, 10, pp. 873-882, (2017); French D.M., Hoff B.W., Spatially dispersive ferrite nonlinear transmission line with axial bias, IEEE Trans. Plasma Sci., 42, 10, pp. 3387-3390, (2014); Priputnev P., Romanchenko I., Maltsev S., Sobyanin R., Konev V., High efficiency radio frequency pulse generation in a nonlinear corrugated coaxial transmission line with ferrite saturated by permanent magnets, Rev. Sci. Instrum., 94, 5, (2023)","G. Deng; Northwest Institute of Nuclear Technology, Key Laboratory of Advanced Science and Technology on High Power Microwave, Xi'an, 710024, China; email: gjdeng@126.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00933813","","ITPSB","","English","IEEE Trans Plasma Sci","Article","Final","","Scopus","2-s2.0-85171573905" +"Kunyangyuen B.; Pinsook U.; Kittiwatanakul S.","Kunyangyuen, Boonthum (58102153300); Pinsook, Udomsilp (6603473659); Kittiwatanakul, Salinporn (48761568000)","58102153300; 6603473659; 48761568000","Ab-initio study and atomistic spin model simulations of Cr2O3thin films","2023","Journal of Physics: Conference Series","2431","1","012042","","","","0","10.1088/1742-6596/2431/1/012042","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85148045875&doi=10.1088%2f1742-6596%2f2431%2f1%2f012042&partnerID=40&md5=b9987db3c687cdaeeec5dbfdc9dc7c18","Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand","Kunyangyuen B., Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Pinsook U., Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Kittiwatanakul S., Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand","Magnetoelectric random access memory (MERAM) is the next generation technology of data storage with high-density and low power. Magnetoelectric material can be controlled by voltage such as an electric field to transform spin domain directions for storing data. One of the most promising materials that possess such properties near room temperature is Cr2O3. Although, the bulk has perfect properties for MERAM, it is necessary to fabricate thin films for applicable spintronic devices, i.e., reducing the required external control voltage; however, the film magnetic and physical properties might be different from bulk. In this work, we propose that the film properties might be induced by surface effects and are confirmed with Ab-initio calculation and atomistic spin simulation. The main simulation processes are the density functional theory (DFT) calculating, mapped with the classical Heisenberg model for exchange interaction constants up to the fifth nearest neighbour (J 1-J 5). The atomistic spin model was then used to approximate the Neel temperature (T N), comparing two methods i.e., Monte Carlo simulation and the Landau-Lifshitz-Gilbert (LLG) equation. The Neel temperatures of the film were found to be slightly lower than the bulk, which is in good agreement with previous experiments. Furthermore, the spin dynamic model gives more correct result comparing to the Monte Carlo method. © Published under licence by IOP Publishing Ltd.","","Density functional theory; Electric fields; Intelligent systems; Monte Carlo methods; Random access storage; Ab initio study; Atomistics; Data storage; Generation technologies; Magnetoelectrics; Modeling simulation; Property; Random access memory; Spin models; Thin-films; Thin films","","","","","NSRF","The authors are grateful to Asst. Prof. Dr. Malika Suewatthana from Mahidol University, Assoc. Prof. Dr. Jessada Chureemart from Magnetic Information Storage Technology (MINT), Mahasarakham University, Asst. Prof. Dr. Annop Ektarawong and Mr. Akkarach Sukserm from Chulalongkorn University for valuable discussion and comments. The authors acknowledge support from the NSRF via","Dzyaloshinskii I E., Sov. Phys. JETP, 10, pp. 628-629, (1960); Kota Y, Imamura H, Sasaki M, IEEE Trans. Magn, 50, (2014); Fallarino L, Binek C, Berger A, Phys. Rev. B, 91, (2015); Mahmood A, Street M, Echtenkamp W, Kwan C P., Bird J P., Binek C, Phys. Rev. Mater, 2, (2018); Street M, Echtenkamp W, Komesu T, Cao S, Dowben P A., Binek C, Appl. Phys. Lett, 104, (2014); Hohenberg P, Kohn W, Phys. Rev, 136, (1965); Giannozzi P, Et al., J. Phys. Condens. Matter, 21, (2009); Xie W, Xiong W, Marianetti C A., Morgan D, Phys. Rev. B, 88, (2013); Timrov I, Marzari N, Cococcioni M, Comput. Phys. Commun, 279, (2022); Bauer B, Et al., J. Stat. Mech, (2011); Evans R F., Fan W J., Chureemart P, Ostler T A., Ellis M O., Chantrell R W., J. Phys. Condens. Matter, 26, (2014); Shi S, Wysocki A L., Belashchenko K D., Phys. Rev. B, 79, (2009); Li YY, Phys. Rev, 102, (1956); He X, Echtenkamp W, Binek C, Ferroelectrics, 426, 1, pp. 81-89, (2012)","B. Kunyangyuen; Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; email: 6470177023@student.chula.ac.th; S. Kittiwatanakul; Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; email: salinporn.k@chula.ac.th","Laosiritaworn Y.; Aukkaravittayapun S.; Aukkaravittayapun S.; Tawkomnoy J.; Soonthornthum B.; Soonthornthum B.","Institute of Physics","Council of Scientific and Technological Associations of Thailand (COSTAT); et al.; Institute for the Promotion of Teaching Science and Technology (IPST); National Astronomical Research Institute of Thailand (NARIT); Synchrotron Light Research Institute (SLRI); Thailand Center of Excellence in Physics (ThEP)","17th Siam Physics Congress: Carbon Neutrality, SPC 2022","22 June 2022 through 24 June 2022","Nakhon Ratchasima","186517","17426588","","","","English","J. Phys. Conf. Ser.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85148045875" +"Guarcello C.; Bergeret F.S.","Guarcello, C. (55779151500); Bergeret, F.S. (6701665289)","55779151500; 6701665289","Thermal noise effects on the magnetization switching of a ferromagnetic anomalous Josephson junction","2021","Chaos, Solitons and Fractals","142","","110384","","","","18","10.1016/j.chaos.2020.110384","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85093977497&doi=10.1016%2fj.chaos.2020.110384&partnerID=40&md5=f65c6859263b5173f3de6d670b183bb9","Dipartimento di Fisica “E.R. Caianiello”, Università di Salerno, Via Giovanni Paolo II, 132, Fisciano (SA), I-84084, Italy; Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, San Sebastián, 20018, Spain; Donostia International Physics Center, Paseo Manuel de Lardizabal 4, San Sebastián, 20018, Spain","Guarcello C., Dipartimento di Fisica “E.R. Caianiello”, Università di Salerno, Via Giovanni Paolo II, 132, Fisciano (SA), I-84084, Italy; Bergeret F.S., Centro de Física de Materiales, Centro Mixto CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, San Sebastián, 20018, Spain, Donostia International Physics Center, Paseo Manuel de Lardizabal 4, San Sebastián, 20018, Spain","We discuss the effects of thermal noise on the magnetic response of a lateral ferromagnetic Josephson junction with spin-orbit coupling and out-of-plane magnetization. The direction of the magnetic moment in the ferromagnetic layer can be inverted by using controlled current pulses. This phenomenon is due to the magnetoelectric effect that couples the flowing charge current and the magnetization of the ferromagnet. We investigate the magnetization reversal effect versus intrinsic parameters of the ferromagnet, such as the Gilbert damping and strength of the spin-orbit coupling. We estimate the magnetization reversing time and find the optimal values of the parameters for fast switching. With the aim of increasing the operation temperature we study the effects induced by thermal fluctuations on the averaged stationary magnetization, and find the conditions that make the system more robust against noise. © 2020 Elsevier Ltd","Anomalous Josephson effect; Ferromagnetic Josephson junction; Landau–Lifshitz–Gilbert (LLG) equation; Magnetization reversal phenomenon; Resistively shunted junction (RSJ) model; Thermal noise effects","Ferromagnetic materials; Ferromagnetism; Josephson junction devices; Magnetic moments; Magnets; Quantum optics; Spin orbit coupling; Superconducting films; Thermal noise; Ferromagnetic Josephson junctions; Ferromagnetic layers; Intrinsic parameters; Josephson-junction; Magnetic response; Magnetization switching; Operation temperature; Thermal fluctuations; Magnetization reversal","","","","","EU's Horizon 2020 research and innovation program; EU’s Horizon 2020 research and innovation program; Grupos Consolidados UPV/EHU del Gobierno Vasco, (IT1249-19); Horizon 2020 Framework Programme, H2020, (800923); Ministerio de Ciencia, Innovación y Universidades, MCIU; Ministerio de Ciencia e Innovación, MICINN, (FIS2017-82804-P)","Funding text 1: F.S.B. acknowledge funding by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) (Project No. FIS2017-82804-P), partial support by Grupos Consolidados UPV/EHU del Gobierno Vasco (Grant No. IT1249-19), and by EU’s Horizon 2020 research and innovation program under Grant Agreement No. 800923 (SUPERTED).; Funding text 2: F.S.B. acknowledge funding by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) (Project No. FIS2017-82804-P), partial support by Grupos Consolidados UPV/EHU del Gobierno Vasco (Grant No. IT1249-19), and by EU's Horizon 2020 research and innovation program under Grant Agreement No. 800923 (SUPERTED).","Assouline A., Feuillet-Palma C., Bergeal N., Zhang T., Mottaghizadeh A., Zimmers A., Lhuillier E., Eddrie M., Atkinson P., Aprili M., Et al., Spin-orbit induced phase-shift in Bi2Se3Josephson junctions, Nat Commun, 10, (2019); Atanasova P.K., Panayotova S.A., Rahmonov I.R., Shukrinov Y.M., Zemlyanaya E.V., Bashashin M.V., Periodicity in the appearance of intervals of the reversal of the magnetic moment of a φ0Josephson junction, JETP Lett, 110, pp. 722-726, (2019); Atanasova P.K., Panayotova S.A., Zemlyanaya E.V., Shukrinov Y.M., Rahmonov I.R., Numerical simulation of the stiff system of equations within the spintronic model, Numerical methods and applications, pp. 301-308, (2019); Barone A., Paterno G., Physics and applications of the Josephson effect, (1982); Bergeret F.S., Tokatly I.V., Theory of diffusive φ0Josephson junctions in the presence of spin-orbit coupling, EPL (Europhysics Letters), 110, (2015); Bergeret F.S., Volkov A.F., Efetov K.B., Odd triplet superconductivity and related phenomena in superconductor-ferromagnet structures, Rev Mod Phys, 77, pp. 1321-1373, (2005); Bobkova I.V., Bobkov A.M., Quasiclassical theory of magnetoelectric effects in superconducting heterostructures in the presence of spin-orbit coupling, Phys Rev B, 95, (2017); Brown W.F., Thermal fluctuations of a single-domain particle, Phys Rev, 130, pp. 1677-1686, (1963); Buzdin A., Direct coupling between magnetism and superconducting current in the Josephson φ0junction, Phys Rev Lett, 101, (2008); Bychkov Y.A., Rashba E.I., Properties of a 2d electron gas with lifted spectral degeneracy, JETP lett, 39, (1984); Coffey W.T., Kalmykov Y.P., Thermal fluctuations of magnetic nanoparticles: fifty years after brown, J Appl Phys, 112, (2012); Edelstein V.M., Magnetoelectric effect in polar superconductors, Phys Rev Lett, 75, pp. 2004-2007, (1995); Edelstein V.M., Magnetoelectric effect in dirty superconductors with broken mirror symmetry, Phys Rev B, 72, (2005); Eschrig M., Spin-polarized supercurrents for spintronics: a review of current progress, Rep Prog Phys, 78, (2015); Feofanov A.K., Oboznov V.A., Bol'ginov V.V., Lisenfeld J., Poletto S., Ryazanov V.V., Rossolenko A.N., Khabipov M., Balashov D., Zorin A.B., Dmitriev P.N., Koshelets V.P., Ustinov A.V., Implementation of superconductor/ferromagnet/ superconductor π-shifters in superconducting digital and quantum circuits, Nat Phys, 6, pp. 593-597, (2010); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans Magn, 40, pp. 3443-3449, (2004); Gingrich E.C., Niedzielski B.M., Glick J.A., Wang Y., Miller D.L., Loloee R., Pratt W.P., Birge N.O., Controllable 0-πJosephson junctions containing a ferromagnetic spin valve, Nat Phys, 12, pp. 564-567, (2016); Golubov A.A., Kupriyanov M.Y., Controlling magnetism, Nat Mater, 16, pp. 156-157, (2017); Guarcello C., Bergeret F., Cryogenic memory element based on an anomalous Josephson junction, Phys Rev Appl, 13, (2020); Guarcello C., Citro R., Durante O., Bergeret F.S., Iorio A., Sanz-Fernandez C., Strambini E., Giazotto F., Braggio A., rf-SQUID measurements of anomalous Josephson effect, Phys Rev Res, 2, (2020); Guarcello C., Giazotto F., Solinas P., Coherent diffraction of thermal currents in long Josephson tunnel junctions, Phys Rev B, 94, (2016); Guarcello C., Solinas P., Di Ventra M., Giazotto F., Solitonic Josephson-based meminductive systems, Sci Rep, 7, (2017); Guarcello C., Valenti D., Augello G., Spagnolo B., The role of non-Gaussian sources in the transient dynamics of long Josephson junctions, Acta Phys Pol B, 44, pp. 997-1005, (2013); Guarcello C., Valenti D., Carollo A., Spagnolo B., Stabilization effects of dichotomous noise on the lifetime of the superconducting state in a long Josephson junction, Entropy, 17, (2015); Guarcello C., Valenti D., Carollo A., Spagnolo B., Effects of Lévy noise on the dynamics of sine-Gordon solitons in long Josephson junctions, J Stat Mech, 2016, (2016); Guarcello C., Valenti D., Spagnolo B., Phase dynamics in graphene-based Josephson junctions in the presence of thermal and correlated fluctuations, Phys Rev B, 92, (2015); Guarcello C., Valenti D., Spagnolo B., Pierro V., Filatrella G., Josephson-based threshold detector for Lévy-distributed current fluctuations, Phys Rev Appl, 11, (2019); Konschelle F., Buzdin A., Magnetic moment manipulation by a Josephson current, Phys Rev Lett, 102, (2009); Konschelle F., Tokatly I.V., Bergeret F.S., Theory of the spin-galvanic effect and the anomalous phase shift φ0in superconductors and Josephson junctions with intrinsic spin-orbit coupling, Phys Rev B, 92, (2015); Kulagina I., Linder J., Spin supercurrent, magnetization dynamics, and φ-state in spin-textured Josephson junctions, Phys Rev B, 90, (2014); Kuzmin L.S., Pankratov A.L., Gordeeva A.V., Zbrozhek V.O., Shamporov V.A., Revin L.S., Blagodatkin A.V., Masi S., de Bernardis P., Photon-noise-limited cold-electron bolometer based on strong electron self-cooling for high-performance cosmology missions, Commun Phys, 2, (2019); Landau L., Lifshitz E., On the theory of magnetic permeability dispersion in ferromagnetic solids, Phys Z Sowjetunion, 8, (1935); Lifshitz E.M., Pitaevskii L.P., Course of theoretical physics, theory of the condensed state, 9, (1990); Linder J., Robinson J.W.A., Superconducting spintronics, Nature Physics, 11, (2015); Mal'shukov A.G., Chu C.S., Spin hall effect in a Josephson contact, Phys Rev B, 78, (2008); Mayer W., Dartiailh M.C., Yuan J., Wickramasinghe K.S., Rossi E., Shabani J., Gate controlled anomalous phase shift in Al/InAs Josephson junctions, Nat Commun, 11, (2020); Mazanik A., Rahmonov I., Botha A., Shukrinov Y., Analytical criteria for magnetization reversal in a φ0Josephson junction, Phys Rev Appl, 14, (2020); Mironov S., Meng H., Buzdin A., Magnetic flux pumping in superconducting loop containing a Josephson ψjunction, Appl Phys Lett, 116, (2020); Nashaat M., Bobkova I.V., Bobkov A.M., Shukrinov Y.M., Rahmonov I.R., Sengupta K., Electrical control of magnetization in superconductor/ferromagnet/superconductor junctions on a three-dimensional topological insulator, Phys Rev B, 100, (2019); Nashaat M., Botha A.E., Shukrinov Y.M., Devil's staircases in the IV characteristics of superconductor/ferromagnet/superconductor Josephson junctions, Phys Rev B, 97, (2018); Nashaat M., Shukrinov Y.M., Irie A., Ellithi A.Y., El Sherbini T.M., Microwave induced tunable subharmonic steps in superconductor–ferromagnet–superconductor Josephson junction, Low Temp Phys, 45, pp. 1246-1251, (2019); Nishino M., Miyashita S., Realization of the thermal equilibrium in inhomogeneous magnetic systems by the Landau-Lifshitz-Gilbert equation with stochastic noise, and its dynamical aspects, Phys Rev B, 91, (2015); Pankratov A.L., Vdovichev S.N., Nefedov I.M., Effect of noise on the high-speed reversal of single-domain uniaxial magnetic nanoparticles, Phys Rev B, 78, (2008); Rahmonov I.R., Tekic J., Mali P., Irie A., Shukrinov Y.M., Ac-driven annular Josephson junctions: the missing Shapiro steps, Phys Rev B, 101, (2020); Rashba E.I., Properties of semiconductors with an extremum loop. I. Cyclotron and combinational resonance in a magnetic field perpendicular to the plane of the loop, Soviet Phys Solid State, 2, pp. 1109-1122, (1960); Revin L.S., Pankratov A.L., Fine tuning of phase qubit parameters for optimization of fast single-pulse readout, Appl Phys Lett, 98, (2011); Roma F., Cugliandolo L.F., Lozano G.S., Numerical integration of the stochastic Landau-Lifshitz-Gilbert equation in generic time-discretization schemes, Phys Rev E, 90, (2014); Shukrinov Y.M., Mazanik A., Rahmonov I.R., Botha A.E., Buzdin A., Re-orientation of the easy axis in φ0-junction, EPL (Europhysics Letters), 122, (2018); Shukrinov Y.M., Nashaat M., Rahmonov I.R., Kulikov K.V., Ferromagnetic resonance and the dynamics of the magnetic moment in a “Josephson Junction–Nanomagnet” system, JETP Lett, 110, pp. 160-165, (2019); Shukrinov Y.M., Rahmonov I.R., Botha A.E., Superconducting spintronics in the presence of spin-orbital coupling, IEEE Trans Appl Supercond, 28, pp. 1-5, (2018); Shukrinov Y.M., Rahmonov I.R., Sengupta K., Ferromagnetic resonance and magnetic precessions in φ0junctions, Phys Rev B, 99, (2019); Shukrinov Y.M., Rahmonov I.R., Sengupta K., Buzdin A., Magnetization reversal by superconducting current in φ0Josephson junctions, Appl Phys Lett, 110, (2017); Smirnov A.A., Pankratov A.L., Influence of the size of uniaxial magnetic nanoparticle on the reliability of high-speed switching, Phys Rev B, 82, (2010); Spagnolo B., Valenti D., Guarcello C., Carollo A., Persano Adorno D., Spezia S., Pizzolato N., Di Paola B., Noise-induced effects in nonlinear relaxation of condensed matter systems, Chaos Solitons Fract, 81, pp. 412-424, (2015); Strambini E., Iorio A., Durante O., Citro R., Sanz-Fernandez C., Guarcello C., Et al., A Josephson phase battery, Nat Nanotechnol, 15, pp. 656-660, (2020); Szombati D.B., Nadj-Perge S., Car D., Plissard S.R., Bakkers E.P.A.M., Kouwenhoven L.P., Josephson φ0-junction in nanowire quantum dots, Nat Phys, 12, pp. 568-572, (2016); Valenti D., Guarcello C., Spagnolo B., Switching times in long-overlap Josephson junctions subject to thermal fluctuations and non-Gaussian noise sources, Phys Rev B, 89, (2014)","C. Guarcello; Dipartimento di Fisica “E.R. Caianiello”, Università di Salerno, Fisciano (SA), Via Giovanni Paolo II, 132, I-84084, Italy; email: cguarcello@unisa.it","","Elsevier Ltd","","","","","","09600779","","CSFOE","","English","Chaos Solitons Fractals","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85093977497" +"Vakili H.; Ganguly S.; De Coster G.J.; Neupane M.R.; Ghosh A.W.","Vakili, Hamed (57218995915); Ganguly, Samiran (56681748200); De Coster, George J. (57204034933); Neupane, Mahesh R. (8966232900); Ghosh, Avik W. (7403963862)","57218995915; 56681748200; 57204034933; 8966232900; 7403963862","Low Power In-Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures","2022","ACS Nano","16","12","","20222","20228","6","3","10.1021/acsnano.2c05645","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85143506565&doi=10.1021%2facsnano.2c05645&partnerID=40&md5=4389d98cbf3f7f4695812379cefb51e5","Department of Physics, University of Virginia, Charlottesville, 22904, VA, United States; Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, 22904, VA, United States; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; DEVCOM Army Research Laboratory, 2800 Powder Mill Road, Adelphi, 20783, MD, United States; Materials Science and Engineering Program, University of California, Riverside, 92521, CA, United States","Vakili H., Department of Physics, University of Virginia, Charlottesville, 22904, VA, United States; Ganguly S., Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, 22904, VA, United States, Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; De Coster G.J., DEVCOM Army Research Laboratory, 2800 Powder Mill Road, Adelphi, 20783, MD, United States; Neupane M.R., DEVCOM Army Research Laboratory, 2800 Powder Mill Road, Adelphi, 20783, MD, United States, Materials Science and Engineering Program, University of California, Riverside, 92521, CA, United States; Ghosh A.W., Department of Physics, University of Virginia, Charlottesville, 22904, VA, United States, Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, 22904, VA, United States","The surface state of a 3D topological insulator (3DTI) is a spin-momentum locked conductive state, whose large spin hall angle can be used for the energy-efficient spin-orbit torque based switching of an overlying ferromagnet (FM). Conversely, the gated switching of the magnetization of a separate FM in or out of the TI surface plane can turn on and off the TI surface current. By exploiting this reciprocal behavior, we can use two FM/3DTI heterostructures to design an integrated 1-transistor 1-magnetic tunnel junction random access memory unit (1T1MTJ RAM) for an ultra low power Processing-in-Memory (PiM) architecture. Our calculation involves combining the Fokker-Planck equation with the Nonequilibrium Green Function (NEGF) based flow of conduction electrons and Landau-Lifshitz-Gilbert (LLG) based dynamics of magnetization. Our combined approach allows us to connect device performance metrics with underlying material parameters, which can guide proposed experimental and fabrication efforts. © 2022 American Chemical Society.","3D topological insulator; ferromagnetic heterostructures; in-memory computing; quantum transport; spintronics","Electric insulators; Energy efficiency; Ferromagnetism; Magnetization; Quantum chemistry; Superconducting materials; Tunnel junctions; 3d topological insulator; Ferromagnetic heterostructure; Ferromagnetics; Ferromagnets; In-memory computing; Low Power; Memory computations; Quantum transport; Spin momentum; Topological insulators; Ferromagnetic materials","","","","","Army Research Lab; National Science Foundation, NSF, (IIP-1439644, IIP-1738752, IIP-1439680, IIP-1939050, IIP-1939012, IIP-1939009, 1738752)","We acknowledge useful discussions with Patrick Taylor (ARL), Joe Poon, Md Golam Morshed (UVA) and Supriyo Bandyopadhyay (VCU). This work is supported by the Army Research Lab (ARL) and in part by the NSF I/UCRC on Multifunctional Integrated System Technology (MIST) Center (IIP-1439644, IIP-1439680, IIP-1738752, IIP-1939009, IIP-1939050, and IIP-1939012).","Chi P., Li S., Xu C., Zhang T., Zhao J., Liu Y., Wang Y., Xie Y., PRIME: A Novel Processing-in-Memory Architecture for Neural Network Computation in ReRAM-Based Main Memory, ACM/IEEE Annual International Symposium on Computer Architecture (ISCA), pp. 27-39, (2016); Ghose S., Boroumand A., Kim J.S., Gomez-Luna J., Mutlu O., Processing-in-memory: A workload-driven perspective, IBM J. Res. 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World Scientific Series in Nanoscience and Nanotechnology, 13, (2016); Vakili H., Xie Y., Ganguly S., Ghosh A.W., Anatomy of nanomagnetic switching at a 3D Topological Insulator PN junction, arXiv,2110.02641, (2021); Vakili H., Ganguly S., De Coster G.J., Neupane M.R., Ghosh A.W., Low power in Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures, arXiv2203.14389, (2022)","H. Vakili; Department of Physics, University of Virginia, Charlottesville, 22904, United States; email: hv8rf@virginia.edu","","American Chemical Society","","","","","","19360851","","","36459145","English","ACS Nano","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85143506565" +"Bouguerra Y.; Mehani S.; Bechane K.; Maamache M.; Hervieux P.-A.","Bouguerra, Y. (15050305500); Mehani, S. (57902541600); Bechane, K. (57902964500); Maamache, M. (6701644497); Hervieux, P.-A. (7003917569)","15050305500; 57902541600; 57902964500; 6701644497; 7003917569","Pseudo- PT symmetric Dirac equation: Effect of a new mean spin angular momentum operator on Gilbert damping","2022","Journal of Physics A: Mathematical and Theoretical","55","42","425302","","","","1","10.1088/1751-8121/ac9262","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85140019055&doi=10.1088%2f1751-8121%2fac9262&partnerID=40&md5=44de9e9331d2ec5084341c548dc0140d","Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif 1, Sétif, 19000, Algeria; Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, 67000, France","Bouguerra Y., Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif 1, Sétif, 19000, Algeria; Mehani S., Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif 1, Sétif, 19000, Algeria; Bechane K., Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif 1, Sétif, 19000, Algeria; Maamache M., Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif 1, Sétif, 19000, Algeria; Hervieux P.-A., Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, 67000, France","The pseudo- PT symmetric Dirac equation is proposed and analyzed by using a non-unitary Foldy-Wouthuysen transformations. A new spin operator PT symmetric expectation value (called the mean spin operator) for an electron interacting with a time-dependent electromagnetic field is obtained. We show that spin magnetization - which is the quantity usually measured experimentally - is not described by the standard spin operator but by this new mean spin operator to properly describe magnetization dynamics in ferromagnetic materials and the corresponding equation of motion is compatible with the phenomenological model of the Landau-Lifshitz-Gilbert equation (LLG). © 2022 IOP Publishing Ltd.","Foldy-Wouthuysen transformation; Landau-Lifshitz-Gilbert equation; non-Hermitian Dirac equation; pseudo PT symmetry","","","","","","","","Gilbert T L., Classics in magnetics a phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, (2004); Kronmuller H, Fahnle M F., Micromagnetism and the Microstructure of Ferromagnetic Solids, (2003); Brataas A, Tserkovnyak Y, Bauer G E. W., Phys. Rev. Lett, 101, (2008); Levy-Leblond J.-M., Commun. Math. Phys, 6, pp. 286-311, (1967); Sakurai J J., Advanced Quantum Mechanics Reading, (1967); Blundell S, Magnetism in Condensed Matter, (2001); Foldy L, Wouthuysen S, Phys. Rev, 78, (1950); Greiner W, Relativistic Quantum Mechanics: Wave Equations, (2000); Bjorken J D., Drell S D., Relativistic Quantum Mechanics, (1964); Hickey M C., Moodera J S., Phys. Rev. Lett, 102, (2009); Wieser R, Phys. Rev. Lett, 110, (2013); Mondal R, Berritta M, Nandy A K., Oppeneer P M., Phys. Rev. B, 96, (2017); Mondal R, Berritta M, Oppeneer P M., J. Phys.: Condens. Matter, 30, (2018); Mondal R, Oppeneer P M., J. Phys.: Condens. Matter, 32, (2020); Mana N, Maamache M, Int. J. Mod. Phys. A, 35, (2020); Bender C M., Boettcher S, Phys. Rev. Lett, 80, (1998); Bender C M., Brody D C., Jones H F., Phys. Rev. Lett, 89, (2002); Dirac P A. M., Proc. R. Soc. London A, 180, pp. 1-40, (1942); Mostafazadeh A, J. Math. 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Sci, 80, pp. 536-541, (2001); Bargmann V, Michel L, Telegdi V L., Phys. Rev. Lett, 2, (1959); Jackson J D., Classical Electrodynamics, (1998)","M. Maamache; Laboratoire de Physique Quantique et Systèmes Dynamiques, Faculté des Sciences, Université Ferhat Abbas, Sétif, Sétif 1, 19000, Algeria; email: maamache@univ-setif.dz; P.-A. Hervieux; Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, 67000, France; email: hervieux@unistra.fr","","Institute of Physics","","","","","","17518113","","","","English","J. Phys. Math. Theor.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85140019055" +"Liao Y.-C.; Nikonov D.E.; Dutta S.; Chang S.-C.; Manipatruni S.; Young I.A.; Naeemi A.","Liao, Yu-Ching (57217100462); Nikonov, Dmitri E. (7003272404); Dutta, Sourav (56640502800); Chang, Sou-Chi (37085140500); Manipatruni, Sasikanth (15832613300); Young, Ian A. (7402362397); Naeemi, Azad (6602173751)","57217100462; 7003272404; 56640502800; 37085140500; 15832613300; 7402362397; 6602173751","Simulation of the Magnetization Dynamics of a Single-Domain BiFeO Nanoisland","2020","IEEE Transactions on Magnetics","56","10","9149627","","","","10","10.1109/TMAG.2020.3011932","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85092091800&doi=10.1109%2fTMAG.2020.3011932&partnerID=40&md5=ec1555cd6cd37af6560f905b8e0df05e","School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States; Components Research, Technology and Manufacturing Group, Intel Corporation, Hillsboro, OR, United States; Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, United States","Liao Y.-C., School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States; Nikonov D.E., Components Research, Technology and Manufacturing Group, Intel Corporation, Hillsboro, OR, United States; Dutta S., Department of Electrical Engineering, University of Notre Dame, Notre Dame, IN, United States; Chang S.-C., Components Research, Technology and Manufacturing Group, Intel Corporation, Hillsboro, OR, United States; Manipatruni S., Components Research, Technology and Manufacturing Group, Intel Corporation, Hillsboro, OR, United States; Young I.A., Components Research, Technology and Manufacturing Group, Intel Corporation, Hillsboro, OR, United States; Naeemi A., School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States","The switching dynamics of a single-domain BiFeO3 nanoscale nanoisland is investigated by studying the dynamics of polarization and Neel vector. We use the Landau-Khalatnikov (LK) equation to describe the evolution of the ferroelectric polarization, and we implement the Landau-Lifshitz-Gilbert (LLG) equations to model the dynamics of spins in two sublattices and the time evolution of the antiferromagnetic order (Neel vector) in a G-type antiferromagnet. Our model can calculate the weak magnetization more accurately compared to previous works on the antiferromagnet using the Neel vector as the order parameter and weak magnetization are often neglected. This work also theoretically demonstrates that the rotation of the magnetic hard-axis, which follows the polarization reversal, can reverse the Neel vector while the weak magnetization remains unchanged. The simulation results are consistent with the ab initio calculations, where the Neel vector rotates during polarization rotation, and also match our calculation of the dynamics of the order parameter using Landau-Ginzburg theory. We also find that the switching time of the Neel vector is a strong function of the polarization switching time and can be as short as 30ps if the polarization can switch faster. However, the Neel vector does not reverse if the polarization switches in less than 30ps. © 1965-2012 IEEE.","Antiferromagnet; BiFeO₃; ferroelectric; magnetoelectric (ME) device; multiferroic","Antiferromagnetic materials; Bismuth compounds; Calculations; Iron compounds; Magnetization reversal; Polarization; Vectors; Ab initio calculations; Antiferromagnetic orderings; Ferroelectric polarization; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Polarization reversals; Polarization switches; Polarization switching; Rotation","","","","","Semiconductor Research Corporation, SRC, (MSR-INTEL TASK 2835.001); Intel Corporation","ACKNOWLEDGMENT This work was supported by Intel Corporation through Semiconductor Research Corporation Task under Grant MSR-INTEL TASK 2835.001.","Nikonov D.E., Young I.A., Overview of beyond-CMOS devices and a uniform methodology for their benchmarking, Proc. 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(59157674200)","6507907076; 57223296180; 57193765286; 58728817900; 7101619622; 59157674200","Current-driven magnetization reversal dynamics and breather-like EM soliton propagation in biaxial anisotropic weak ferromagnetic nanowire","2022","Nonlinear Dynamics","107","3","","2667","2687","20","1","10.1007/s11071-021-06997-w","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85122821099&doi=10.1007%2fs11071-021-06997-w&partnerID=40&md5=9f11156e394533fd669872545cfcc350","Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Tamil Nadu, Thiruvarur, 610 005, India; The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy; Department of Physics, Periyar University, Tamil Nadu, Salem, 636 011, India; Condensed Matter Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102, India; Department of Chemistry, Periyar University, Tamil Nadu, Salem, 636 011, India","Kavitha L., Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Tamil Nadu, Thiruvarur, 610 005, India, The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy; Pavithra T., Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Tamil Nadu, Thiruvarur, 610 005, India; Boopathy C., Department of Physics, Periyar University, Tamil Nadu, Salem, 636 011, India; Kumar V.S., Department of Physics, Periyar University, Tamil Nadu, Salem, 636 011, India; Mani A., Condensed Matter Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603102, India; Gopi D., Department of Chemistry, Periyar University, Tamil Nadu, Salem, 636 011, India","We investigate the effect of spin torque on the switching dynamics of magnetic solitons in a weak ferromagnetic nanowire under the influence of an electromagnetic wave (EMW). The magnetization dynamics of the current-driven ferromagnetic nanowire and the EMW propagation is governed by the celebrated Landau-Lifshitz-Gilbert (LLG) vector equation and the Maxwell’s equations, respectively. We recast the set of LLG and Maxwell equations onto the extended derivative nonlinear Schro¨ dinger (EDNLS) equation. We employ the nonlinear perturbation analysis along the lines of Kodama and Ablowitz and analyze the interplay of the Dzyaloshinskii-Moriya interaction (DMI) along with the spin transfer torque on the magnetization reversal dynamics by solving the associated evolution equations for the soliton parameters. We also demonstrate the spin-polarized current triggers an ultrafast switching of EM solitons in the ferromagnetic nanowire in the range of 0.58-0.12ns, and the Gilbert damping supports the EM soliton switching to sustain indefinitely. We invoke the Jacobi elliptic function method to explore the propagation of breather-like solitonic localized modes along the ferromagnetic nanowire. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.","Electromagnetic soliton; Landau-Lifshitz-Gilbert equation; Magnetization reversal; Reductive perturbation method; Spin transfer torque","Dynamics; Electromagnetic waves; Ferromagnetic materials; Ferromagnetism; Magnetization reversal; Nanowires; Nonlinear equations; Perturbation techniques; Solitons; Spin dynamics; Current-driven; Electromagnetic solitons; Ferromagnetic nanowire; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Magnetization - reversal; Magnetization reversal dynamics; Reductive perturbation methods; Soliton propagation; Spin transfer torque; Maxwell equations","","","","","DST-SERB, (MTR/2017/000314/MS); UGC-DAE; Council of Scientific and Industrial Research, India, CSIR, (:03(1418)/17/EMR-II); Council of Scientific and Industrial Research, India, CSIR; Abdus Salam International Centre for Theoretical Physics, ICTP","L.K. gratefully acknowledges the financial support in the form of Major Research Projects by CSIR (Ref.No.:03(1418)/17/EMR-II), India, DST-SERB (Ref.No.: MTR/2017/000314/MS), India, and ICTP, Italy, in the form of a Regular Associateship. LK and TP acknowledge the financial support from UGC-DAE (Ref.No.:CSR-KN/CRS-102/2019-20) in the form of a major research project. ","Martin C.R., Template synthesis of polymeric and metal microtubules, Adv. Mater., 3, pp. 457-459, (1991); de Visser A., Louis E., Franse J.J.M., Menovsky A., Forced magnetostriction of heavy-fermion UPt3, J. Magn. Magn. Mater., 54, pp. 387-388, (1986); Ferre R., Ounadjela K., George J.M., Piraux L., Dubois S., Magnetization processes in nickel and cobalt electrodeposited nanowires, Phys. Rev. B, 56, pp. 14066-14075, (1997); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, pp. L1-L7, (1996); Sun J.Z., Spin-current interaction with a monodomain magnetic body: a model study, Phys. Rev. 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Kavitha; Department of Physics, School of Basic and Applied Sciences, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, 610 005, India; email: lkavitha@cutn.ac.in","","Springer Science and Business Media B.V.","","","","","","0924090X","","NODYE","","English","Nonlinear Dyn","Article","Final","","Scopus","2-s2.0-85122821099" +"Li J.; Dong H.; Pan X.; Peng C.; Gan X.; Gao Y.; Ren W.; He X.","Li, Junru (56159267400); Dong, Hongmei (57224618323); Pan, Xinghong (57847209700); Peng, Chunrui (57215692692); Gan, Xiuxiu (57224620376); Gao, Yang (57169199100); Ren, Wanchun (49964275500); He, Xuefeng (49863184700)","56159267400; 57224618323; 57847209700; 57215692692; 57224620376; 57169199100; 49964275500; 49863184700","Influence of Permeability Dispersion on Radiation of BAW Antenna: Modeling of Multiphysics Dynamic Coupling","2022","IEEE Transactions on Antennas and Propagation","70","11","","10318","10326","8","14","10.1109/TAP.2022.3195459","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85136129400&doi=10.1109%2fTAP.2022.3195459&partnerID=40&md5=15fe5da012923ac3382f101ec2085bbb","Chongqing University, College of Optoelectronic Engineering, Chongqing, 400044, China; Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; University of Electronic Science and Technology of China, School of Electronic Science and Engineering, Chengdu, 611731, China; University of Electronic Science and Technology of China, School of Mechanical and Electrical Engineering, Chengdu, 611731, China","Li J., Chongqing University, College of Optoelectronic Engineering, Chongqing, 400044, China; Dong H., Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; Pan X., University of Electronic Science and Technology of China, School of Electronic Science and Engineering, Chengdu, 611731, China; Peng C., University of Electronic Science and Technology of China, School of Mechanical and Electrical Engineering, Chengdu, 611731, China; Gan X., Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; Gao Y., Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; Ren W., Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; He X., Chongqing University, College of Optoelectronic Engineering, Chongqing, 400044, China","Coupling of multiphysics including electrodynamics, elastodynamics, magnetodynamics, and electromagnetic (EM) radiation is involved in the operating process of bulk acoustic wave (BAW) antenna. There is still no good way to design the structure and evaluate the performance of the antenna in theory. Therefore, the multiphysics dynamic coupling model of the antenna is constructed by uniting Newton's equation for acoustic wave, Maxwell's equation for EM wave, and Landau-Lifshitz-Gilbert (LLG) equation for spin wave with constitutive relations of multiferroic materials to discuss the dispersion law of permeability and magnetomechanical coupling factor for the magnetostrictive layer. The importance of consistency between ferromagnetic resonance (FMR) frequency and BAW resonant frequency is demonstrated. The analysis shows that both increasing the anisotropic field or the saturation magnetization and decreasing the FMR linewidth are beneficial to improving the internal energy conversion efficiency and the average radiated power for BAW antenna. In addition, a micromagnetic module is introduced into finite element analysis (FEA) software to simulate the precession of unit magnetic moment at different frequencies. Thus, the analytical model is verified from the perspective of power absorption. © 1963-2012 IEEE.","Bulk acoustic wave (BAW); ferromagnetic resonance (FMR); magnetomechanical coupling factor; multiferroic materials; multiphysics coupling; permeability dispersion; radiation","Acoustic waves; Antennas; Couplings; Dispersion (waves); Electromagnetic waves; Energy conversion efficiency; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic moments; Maxwell equations; Natural frequencies; Radiation effects; Saturation magnetization; Spin waves; Antenna modelling; Bulk acoustic waves; Coupling factor; Magnetomechanical coupling factor; Magnetomechanical couplings; Multi-physics; Multi-physics couplings; Multiferroic materials; Permeability dispersion; Wave antennas; Multiphysics","","","","","","","Zaeimbashi M., Et al., Ultra-compact dual-band smart NEMS magnetoelectric antennas for simultaneous wireless energy harvesting and magnetic field sensing, Nature Commun, 12, 1, (2021); Lin H., Et al., NEMS magnetoelectric antennas for biomedical application, Proc. 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Jpn, 5, 6, pp. 502-508, (1990); Gan X., Li J., Dong H., Gao Y., Ren W., Derivation of dispersion coupling permittivity/permeability of magnetoelectric composite materials, Proc. 15th Symp. Piezoelectrcity, Acoustic Waves Device Appl. (SPAWDA), pp. 504-507, (2021); Melkov G.A., Slobodianiuk D.V., Tiberkevich V.S., De Loubens G., Klein O., Slavin A.N., Nonlinear ferromagnetic resonance in nanostructures having discrete spectrum of spin-wave modes, IEEE Magn. Lett, 4, (2013); Neudecker I., Woltersdorf G., Heinrich B., Okuno T., Gubbiotti G., Back C.H., Comparison of frequency, field, and time domain ferromagnetic resonance methods, J. Magn. Magn. Mater, 307, 1, pp. 148-156, (2006); Tiwari S., Et al., Ferromagnetic resonance in bulk-acoustic wave multiferroic devices, Solid-State, Actuat., Microsyst. Workshop Tech. Dig., pp. 420-423, (2016); Labanowski D., Jung A., Salahuddin S., Power absorption in acoustically driven ferromagnetic resonance, Appl. Phys. Lett, 108, 2, (2016); Bickford J.A., Duwel A.E., Weinberg M.S., McNabb R.S., Freeman D.K., Ward P.A., Performance of electrically small conventional and mechanical antennas, IEEE Trans. Antennas Propag, 67, 4, pp. 2209-2223, (2019); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Perspectives in Theoretical Physics. Amsterdam, The Netherlands: Elsevier, pp. 51-65, (1992); Melcher C., Thin-film limits for Landau-Lifshitz-Gilbert equations, SIAM J. Math. Anal, 42, 1, pp. 519-537, (2010); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Jpn. J. Appl. Math, 2, 1, pp. 69-84, (1985); Bruckner F., Et al., Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations, J. Magn. Magn. Mater, 343, pp. 163-168, (2013); Luong K.Q.T., Wang Y., Analysis of dynamic magnetoelastic coupling in mechanically driven magnetoelectric antennas, Sensors, 22, 2, (2022); Yang W.-G., Schmidt H., Acoustic control of magnetism toward energy-efficient applications, Appl. Phys. Rev, 8, 2, (2021)","X. He; Chongqing University, College of Optoelectronic Engineering, Chongqing, 400044, China; email: hexuefeng@cqu.edu.cn; Y. Gao; Southwest University of Science and Technology, School of Information Engineering, Mianyang, 621010, China; email: 29636791@qq.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","0018926X","","IETPA","","English","IEEE Trans Antennas Propag","Article","Final","","Scopus","2-s2.0-85136129400" +"Suresh A.; Bajpai U.; Petrović M.D.; Yang H.; Nikolić B.K.","Suresh, Abhin (57217281246); Bajpai, Utkarsh (57204777363); Petrović, Marko D. (55928482300); Yang, Hyunsoo (37092045800); Nikolić, Branislav K. (7006055333)","57217281246; 57204777363; 55928482300; 37092045800; 7006055333","Magnon- versus Electron-Mediated Spin-Transfer Torque Exerted by Spin Current across an Antiferromagnetic Insulator to Switch the Magnetization of an Adjacent Ferromagnetic Metal","2021","Physical Review Applied","15","3","034089","","","","16","10.1103/PhysRevApplied.15.034089","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85103780547&doi=10.1103%2fPhysRevApplied.15.034089&partnerID=40&md5=6c289c055b172b2c1c85ec4d510df2dd","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore; Kavli Institute for Theoretical Physics, University of California, Santa Barbara, 93106-4030, CA, United States","Suresh A., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Bajpai U., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Petrović M.D., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Yang H., Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States, Kavli Institute for Theoretical Physics, University of California, Santa Barbara, 93106-4030, CA, United States","The recent experiment [Y. Wang et al., Science 366, 1125 (2019)] on magnon-mediated spin-transfer torque (MSTT) was interpreted in terms of a picture where magnons are excited within an antiferromagnetic insulator (AFI), by applying nonequilibrium electronic spin density at one of its surfaces, so that their propagation across AFI deprived of conduction electrons eventually leads to reversal of magnetization of a ferromagnetic metal (FM) attached to the opposite surface of an AFI. However, microscopic (i.e., Hamiltonian-based) understanding of how magnonic and electronic spin currents, both of which can exert torque on localized magnetic moments within FM, are generated and interconverted at multiple junction interfaces is lacking. We employ recently developed time-dependent nonequilibrium Green functions combined with the Landau-Lifshitz-Gilbert equation (TDNEGF+LLG) formalism to evolve conduction electrons quantum mechanically while they interact via self-consistent backaction with localized magnetic moments described classically by atomistic spin dynamics solving a system of LLG equations. Upon injection of square current pulse as the initial condition, TDNEGF+LLG simulations of FM-polarizer/AFI/FM-analyzer junctions show that reversal of localized magnetic moments within a FM analyzer is less efficient, in the sense of requiring larger pulse height and its longer duration, than conventional electron-mediated STT (ESTT) driving magnetization switching in a standard FM-polarizer/normal-metal/FM-analyzer spin valve. Since both electronic, generated by spin pumping from AFI, and magnonic, generated by direct transmission from AFI, spin currents are injected into the FM analyzer, its localized magnetic moments will experience combined MSTT and ESTT. Nevertheless, by artificially turning off ESTT we demonstrate that MSTT plays a dominant role whose understanding, therefore, paves the way for all-magnon-driven magnetization switching devices with no electronic parts. © 2021 American Physical Society.","","Antiferromagnetism; Electron tubes; Electrons; Ferromagnetic materials; Ferromagnetism; Frequency modulation; Magnetic moments; Magnetization reversal; Optical instruments; Polarization; Spin waves; Antiferromagnetic insulators; Conduction electrons; Electronic spin density; Landau-Lifshitz-Gilbert equations; Localized magnetic moments; Magnetization switching; Non-equilibrium green functions; Spin transfer torque; Spin fluctuations","","","","","National Science Foundation, NSF; Directorate for Mathematical and Physical Sciences, MPS, (1748958)","","Yan P., Wang X. S., Wang X. R., All-Magnonic Spin-Transfer Torque and Domain Wall Propagation, Phys. Rev. Lett, 107, (2011); Hinzke D., Nowak U., Domain Wall Motion by the Magnonic Spin Seebeck Effect, Phys. Rev. Lett, 107, (2011); Kovalev A. A., Tserkovnyak Y., Thermomagnonic spin transfer and peltier effects in insulating magnets, EPL (Europhysics Letters), 97, (2012); Cheng R., Xiao D., Zhu J.-G., Antiferromagnet-based magnonic spin-transfer torque, Phys. Rev. B, 98, (2018); Cheng Y., Chen K., Zhang S., Giant magneto-spin-seebeck effect and magnon transfer torques in insulating spin valves, Appl. Phys. Lett, 112, (2018); Cheng Y., Wang W., Zhang S., Amplification of spin-transfer torque in magnetic tunnel junctions with an antiferromagnetic barrier, Phys. Rev. B, 99, (2019); Kim S.-K., Micromagnetic computer simulations of spin waves in nanometre-scale patterned magnetic elements, J. Phys. D: Appl. Phys, 43, (2010); Evans R. F. L., Fan W. J., Chureemart P., Ostler T. A., Ellis M. O. A., Chantrell R. W., Atomistic spin model simulations of magnetic nanomaterials, J. Phys.: Condens. 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K., Magnon-driven chiral charge and spin pumping and electron-magnon scattering from time-dependent quantum transport combined with classical atomistic spin dynamics, Phys. Rev. B, 101, (2020); Ralph D., Stiles M., Spin transfer torques, J. Magn. Mater, 320, (2008); Tatara G., Effective gauge field theory of spintronics, Physica E, 106, (2019); Tsoi M., Jansen A. G. M., Bass J., Chiang W. C., Tsoi V., Wyder P., Generation and detection of phase-coherent current-driven magnons in magnetic multilayers, Nature, 406, (2000); Katine J. A., Albert F. J., Buhrman R. A., Myers E. B., Ralph D. C., Current-Driven Magnetization Reversal and Spin-Wave Excitations in (Equation presented) Pillars, Phys. Rev. Lett, 84, (2000); Stiles M. D., Zangwill A., Anatomy of spin-transfer torque, Phys. Rev. B, 66, (2002); Wang S., Xu Y., Xia K., First-principles study of spin-transfer torques in layered systems with noncollinear magnetization, Phys. Rev. B, 77, (2008); Han J., Zhang P., Hou J. T., Siddiqui S. A., Liu L., Mutual control of coherent spin waves and magnetic domain walls in a magnonic device, Science, 366, (2019); Wang Y., Et al., Magnetization switching by magnon-mediated spin torque through anantiferromagnetic insulator, Science, 366, (2019); Manchon A., Miron I. M., Jungwirth T., Sinova J., Zelezny J., Thiaville A., Garello K., Gambardella P., Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems, Rev. Mod. Phys, 91, (2019); Bauer G. E., Tserkovnyak Y., Viewpoint: Spin-magnon transmutation, Physics, 4, (2011); Petrovic M. D., Popescu B. S., Bajpai U., Plechac P., Nikolic B. K., Spin and charge pumping by a steady or pulse-current-driven magnetic domain wall: A self-consistent multiscale time-dependent quantum-classical hybrid approach, Phys. Rev. Appl, 10, (2018); Bajpai U., Nikolic B. K., Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions, Phys. Rev. B, 99, (2019); Petrovic M. D., Plechac P., Nikolic B. K., Annihilation of topological solitons in magnetism with spin wave burst finale: The role of nonequilibrium electrons causing nonlocal damping and spin pumping over ultrabroadband frequency range, (2019); Bostrom E. V., Verdozzi C., Steering magnetic skyrmions with currents: A nonequilibrium green's functions approach, Phys. Stat. Solidi B, 256, (2019); Stefanucci G., van Leeuwen R., Nonequilibrium Many-Body Theory of Quantum Systems: A Modern Introduction, (2013); Gaury B., Weston J., Santin M., Houzet M., Groth C., Waintal X., Numerical simulations of time-resolved quantum electronics, Phys. Rep, 534, (2014); Berkov D. V., Miltat J., Spin-torque driven magnetization dynamics: Micromagnetic modeling, J. Magn. Magn. Mater, 320, (2008); Wieser R., Description of a dissipative quantum spin dynamics with a Landau-Lifshitz-Gilbert like damping and complete derivation of the classical Landau-Lifshitz equation, Euro. Phys. J. B, 88, (2015); Mondal P., Bajpai U., Petrovic M. D., Plechac P. P., Nikolic B. K., Quantum spin-transfer torque induced nonclassical magnetization dynamics and electron-magnetization entanglement, Phys. Rev. B, 99, (2019); Karolak M., Ulm G., Wehling T., Mazurenko Y., Poteryaev A., Lichtenstein A., Double counting in LDA+DMFT-The example of (Equation presented), J. Electron Spectrosc. Relat. Phenom, 181, (2010); Salahuddin S., Datta S., Self-consistent simulation of quantum transport and magnetization dynamics in spin-torque based devices, Appl. Phys. Lett, 89, (2006); Lu Y., Guo J., Quantum simulation of topological insulator based spin transfer torque device, Appl. Phys. Lett, 102, (2013); Ellis M. O. A., Stamenova M., Sanvito S., Multiscale modeling of current-induced switching in magnetic tunnel junctions using ab initio spin-transfer torques, Phys. Rev. B, 96, (2017); Cooper R. L., Uehling E. A., Ferromagnetic resonance and spin diffusion in supermalloy, Phys. Rev, 164, (1967); Kambersky V., Spin-orbital gilbert damping in common magnetic metals, Phys. Rev. B, 76, (2007); Gilmore K., Idzerda Y. U., Stiles M. D., Identification of the Dominant Precession-Damping Mechanism in (Equation presented), (Equation presented), and (Equation presented) by First-Principles Calculations, Phys. Rev. Lett, 99, (2007); Croy A., Saalmann U., Propagation scheme for nonequilibrium dynamics of electron transport in nanoscale devices, Phys. Rev. B, 80, (2009); Popescu B. S., Croy A., Efficient auxiliary-mode approach for time-dependent nanoelectronics, News J. Phys, 18, (2016); Stahl C., Potthoff M., Anomalous Spin Precession under a Geometrical Torque, Phys. Rev. Lett, 119, (2017); Bajpai U., Nikolic B. K., Spintronics Meets Nonadiabatic Molecular Dynamics: Geometric Spin Torque and Damping on Dynamical Classical Magnetic Texture due to an Electronic Open Quantum System, Phys. Rev. Lett, 125, (2020); Nikolic B. K., Zarbo L. P., Souma S., Imaging mesoscopic spin hall fow: Spatial distribution of local spin currents and spin densities in and out of multiterminal spin-orbit coupled semiconductor nanostructures, Phys. Rev. B, 73, (2006); Thygesen K. S., Jacobsen K. W., Interference and (Equation presented)-point sampling in the supercell approach to phase-coherent transport, Phys. Rev. B, 72, (2005); Mahfouzi F., Nikolic B. K., Kioussis N., Antidamping spin-orbit torque driven by spin-flip reflection mechanism on the surface of a topological insulator: A time-dependent nonequilibrium Green function approach, Phys. Rev. B, 93, (2016); Bode N., Arrachea L., Lozano G. S., Nunner T. S., von Oppen F., Current-induced switching in transport through anisotropic magnetic molecules, Phys. Rev. B, 85, (2012); Zhang S., Li Z., Roles of Nonequilibrium Conduction Electrons on the Magnetization Dynamics of Ferromagnets, Phys. Rev. Lett, 93, (2004); Zhang S., Zhang S. S.-L., Generalization of the Landau-Lifshitz-Gilbert Equation for Conducting Ferromagnets, Phys. Rev. Lett, 102, (2009); Lee K.-J., Stiles M. D., Lee H.-W., Moon J.-H., Kim K.-W., Lee S.-W., Self-consistent calculation of spin transport and magnetization dynamics, Phys. Rep, 531, (2013); Sayad M., Potthoff M., Spin dynamics and relaxation in the classical-spin kondo-impurity model beyond the Landau-Lifschitz-Gilbert equation, New J. Phys, 17, (2015); Bansil A., Lin H., Das T., Colloquium: Topological band theory, Rev. Mod. Phys, 88, (2016); Chang P.-H., Markussen T., Smidstrup S., Stokbro K., Nikolic B. K., Nonequilibrium spin texture within a thin layer below the surface of current-carrying topological insulator (Equation presented): A first-principles quantum transport study, Phys. Rev. B, 92, (2015); Tserkovnyak Y., Brataas A., Bauer G. E. W., Halperin B. I., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Rev. Mod. Phys, 77, (2005); Tatara G., Mizukami S., Consistent microscopic analysis of spin pumping effects, Phys. Rev. B, 96, (2017); Chen S.-H, Chang C.-R, Xiao J. Q., Nikolic B. K., Spin and charge pumping in magnetic tunnel junctions with precessing magnetization: A nonequilibrium Green function approach, Phys. Rev. B, 79, (2009); Foa Torres L. E. F., Mono-parametric quantum charge pumping: Interplay between spatial interference and photon-assisted tunneling, Phys. Rev. B, 72, (2005); Bajpai U., Popescu B. S., Plechac P., Nikolic B. K., Foa Torres L. E. F., Ishizuka H., Nagaosa N., Spatio-temporal dynamics of shift current quantum pumping by femtosecond light pulse, J. Phys.: Mater, 2, (2019); Kohno H., Tatara G., Shibata J., Microscopic calculation of spin torques in disordered ferromagnets, J. Phys. Soc. Japan, 75, (2006); Schuetz F., Kopietz P., Kollar M., What are spin currents in Heisenberg magnets?, Eur. Phys. J. B, 41, (2004)","B.K. Nikolić; Department of Physics and Astronomy, University of Delaware, Newark, 19716, United States; email: bnikolic@udel.edu","","American Physical Society","","","","","","23317019","","","","English","Phys. Rev. Appl.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85103780547" +"Goldys B.; Grotowski J.F.; Le K.-N.","Goldys, Beniamin (6603793051); Grotowski, Joseph F. (6603397000); Le, Kim-Ngan (55844726000)","6603793051; 6603397000; 55844726000","Weak martingale solutions to the stochastic Landau–Lifshitz–Gilbert equation with multi-dimensional noise via a convergent finite-element scheme","2020","Stochastic Processes and their Applications","130","1","","232","261","29","6","10.1016/j.spa.2019.02.011","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85063036797&doi=10.1016%2fj.spa.2019.02.011&partnerID=40&md5=56c26f11c5f08cee8a15fec024d5cce1","School of Mathematics and Statistics, The University of Sydney, Sydney, 2006, Australia; School of Mathematics and Physics, The University of Queensland, QLD 4072, Australia; School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia","Goldys B., School of Mathematics and Statistics, The University of Sydney, Sydney, 2006, Australia; Grotowski J.F., School of Mathematics and Physics, The University of Queensland, QLD 4072, Australia; Le K.-N., School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia","We propose an unconditionally convergent linear finite element scheme for the stochastic Landau–Lifshitz–Gilbert (LLG) equation with multi-dimensional noise. By using the Doss–Sussmann technique, we first transform the stochastic LLG equation into a partial differential equation that depends on the solution of the auxiliary equation for the diffusion part. The resulting equation has solutions absolutely continuous with respect to time. We then propose a convergent θ-linear scheme for the numerical solution of the reformulated equation. As a consequence, we are able to show the existence of weak martingale solutions to the stochastic LLG equation. © 2019 Elsevier B.V.","Ferromagnetism; Finite element; Landau–Lifshitz–Gilbert equation; Stochastic partial differential equation","Ferromagnetism; Finite element method; Partial differential equations; Auxiliary equations; Finite element schemes; Linear finite elements; LLG equation; Martingale solutions; Multi dimensional; Numerical solution; Stochastic partial differential equation; Stochastic systems","","","","","Vivien Challis; Australian Research Council, ARC, (DP140101193, DP160101755); Australian Respiratory Council, ARC","Funding text 1: The authors acknowledge financial support through the ARC, Australia Discovery projects DP140101193 and DP160101755. They are grateful to Vivien Challis for a number of helpful conversations.; Funding text 2: The authors acknowledge financial support through the ARC, Australia Discovery projects DP140101193 and DP160101755 . They are grateful to Vivien Challis for a number of helpful conversations. ","Alouges F., A new finite element scheme for landau–lifshitz equations, Discrete Continuous Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., de Bouard A., Hocquet A., A semi-discrete scheme for the stochastic landau–lifshitz equation, Stoch. Partial Differ. Equ. Anal. Comput., 2, pp. 281-315, (2014); Alouges F., Jaisson P., Convergence of a finite element discretization for the landau-lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci., 16, pp. 299-316, (2006); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, pp. 220-238, (2005); Banas L., Brzezniak Z., Prohl A., Neklyudov M., A convergent finite-element-based discretization of the stochastic Landau–Lifshitz–Gilbert equation, IMA J. Numer. Anal., (2013); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, pp. 1677-1686, (1963); Brown W., Thermal fluctuation of fine ferromagnetic particles, IEEE Trans. Magn., 15, pp. 1196-1208, (1979); Brzezniak Z., Goldys B., Jegaraj T., Weak solutions of a stochastic landau–lifshitz–gilbert equation, Appl. Math. Res. eXpress, pp. 1-33, (2012); Cimrak I., A survey on the numerics and computations for the landau-lifshitz equation of micromagnetism, Arch. Comput. Methods Eng., 15, pp. 277-309, (2008); Da Prato G., Zabczyk J., Stochastic equations in infinite dimensions, Encyclopedia of Mathematics and its Applications, (2014); Doss H., Liens entre équations différentielles stochastiques et ordinaires, Ann. Probab. Stat., vol. 13, pp. 99-125, (1977); Gilbert T., A lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev., 100, pp. 1243-1255, (1955); Goldys B., Le K.-N., Tran T., A finite element approximation for the stochastic landau–lifshitz–gilbert equation, J. Differential Equations, 260, pp. 937-970, (2016); Johnson C., Numerical Solution of Partial Differential Equations by the Finite Element Method, (1987); Ju G., Peng Y., Chang E.K.C., Ding Y., Wu A.Q., Zhu X., Kubota Y., Klemmer T.J., Amini H., Gao L., Fan Z., Rausch T., Subedi P., Ma M., Kalarickal S., Rea C.J., Dimitrov D.V., Huang P.W., Wang K., Chen X., Peng C., Chen W., Dykes J.W., Seigler M.A., Gage E.C., Chantrell R., Thiele J.U., High density heat-assisted magnetic recording media and advanced characterization –progress and challenges, IEEE Trans. Magn., 51, pp. 1-9, (2015); Kallenberg O., Foundations of Modern Probability Probability and Its Applications, (2002); Kunita H., Stochastic flows and stochastic differential equations, Cambridge Studies in Advanced Mathematics, 24, (1990); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-168, (1935); Neel L., Bases d'une nouvelle théorie générale du champ coercitif, Ann. Univ. Grenoble, 22, pp. 299-343, (1946); Sussmann H.J., An interpretation of stochastic differential equations as ordinary differential equations which depend on the sample point, Bull. Amer. Math. Soc., 83, pp. 296-298, (1977)","K.-N. Le; School of mathematical Sciences, Monash University, VIC 3800, Australia; email: n.le-kim@unsw.edu.au","","Elsevier B.V.","","","","","","03044149","","STOPB","","English","Stoch. Processes Appl.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85063036797" +"Fadhilah U.; Kurniawan C.; Djuhana D.","Fadhilah, Ummaira (57208300845); Kurniawan, Candra (55600299500); Djuhana, Dede (26027849100)","57208300845; 55600299500; 26027849100","Investigation of Dynamic Magnetization in FePt and FePd Disk Ferromagnets Using Micromagnetic Simulation","2019","IOP Conference Series: Materials Science and Engineering","553","1","012010","","","","0","10.1088/1757-899X/553/1/012010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85076089521&doi=10.1088%2f1757-899X%2f553%2f1%2f012010&partnerID=40&md5=394291b266aa1ea9a18df2d0341bd713","Department of Physics, FMIPA Universitas Indonesia, UI Depok, Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area, Tangerang Selatan, 15314, Indonesia","Fadhilah U., Department of Physics, FMIPA Universitas Indonesia, UI Depok, Depok, 16424, Indonesia; Kurniawan C., Department of Physics, FMIPA Universitas Indonesia, UI Depok, Depok, 16424, Indonesia, Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area, Tangerang Selatan, 15314, Indonesia; Djuhana D., Department of Physics, FMIPA Universitas Indonesia, UI Depok, Depok, 16424, Indonesia","In this study, we have observed the magnetic hysteresis loop of the highly anisotropic ferromagnetic materials FePt and FePd with disk model by micromagnetic simulation method based on the Landau-Lifshitz-Gilbert (LLG) equation. We used disk shaped model with varied size from 50 to 500 nm, thicknesses of 5 and 10 nm, and damping constant = 0.05. The cell size of 2.5 × 2.5 × 2.5 nm3 was used and the in-plane and out-plane fields were applied to the materials. The results showed that the hysteresis loop has a large coercivity when the external in-plane field and close to zero when the external out-of-plane field was applied. This characteristic was similar as typical of the material's hysteresis loops given the field toward the hard-axis. However, coercivity still observed in materials with size below ≤ 100 nm with ranging values between 20 and 80 mT. From the results, a certain value of the coercivity field appeared in out-plane applied field indicated a perpendicular magnetic anisotropy (PMA) behaviour in FePt and FePd ferromagnets. Moreover, the nucleation field was shifted as the material's size varied. The results showed that the size affected the magnetic properties of the FePt and FePd thin layers. © Published under licence by IOP Publishing Ltd.","Fepd; Fept; Hysteresis loop; Micromagnetic simulation; Pma","Binary alloys; Coercive force; Ferromagnetic materials; Ferromagnetism; Hysteresis; Hysteresis loops; Magnetic anisotropy; Magnetic logic devices; Magnets; Palladium alloys; Platinum alloys; Coercivity field; Damping constants; Dynamic magnetization; Fepd; Fept; Landau-Lifshitz-Gilbert equations; Micromagnetic simulations; Perpendicular magnetic anisotropy; Iron alloys","","","","","Indexed International Publication","This work is supported by Indexed International Publication Grant (Publikasi Internasional Terindeks, PIT 9) year 2019 No. NKB-0023/UN2.R3.1/HKP.05.00/2019 through DRPM Universitas Indonesia.","Tudu B., Tiwari A., Recent Developments in Perpendicular Magnetic Anisotropy Thin Films for Data Storage Applications, Vacuum, 146, pp. 329-341, (2017); Constantin L., Mihai D., Micromagnetic analysis of magnetization behavior in Permalloy nanoparticles for data storage applications, 11th Intrnational Conf. Dev. Appl. Syst., (2012); Bian B., Laughlin D.E., Fabrication and nanostructure of oriented FePt particles, J. Appl. Phys., 87, 9, (2000); Rellinghaus B., Stappert S., Acet M., Wassermann E.F., Magnetic properties of FePt nanoparticles, J. Magn. Magn. Mater., 266, pp. 142-154, (2003); Lukaszew R.A., Cebollada A., Clavero C., Garcia-Martin J.M., Highly ordered FEPT and FePd magnetic nano-structures: Correlated structural and magnetic studies, Phys. B, 384, pp. 15-18, (2006); Bonell F., Murakami S., Shiota Y., Nozaki T., Shinjo T., Suzuki Y., Large change in perpendicular magnetic anisotropy induced by an electric field in FePd ultrathin films, Appl. Phys. Lett., 98, (2011); Sun S., Recent Advances in Chemical Synthesis, Self-Assembly, and Applications of FePt Nanoparticles, Adv. Mater., 18, pp. 393-403, (2006); Sato K., Hirotsu Y., Structure and magnetic property changes of epitaxially grown L10-FePd isolated nanoparticles on annealing, J. Appl. Phys., 93, (2003); Skuza J.R., Clavero C., Yang K., Wincheski B., Lukaszew R.A., Microstructural, magnetic anisotropy, and magnetic domain structure correlations in epitaxial FePd thin films with perpendicular magnetic anisotropy, IEEE Transaction on Magnetics, 46, (2010); Donahue M.J., Porter D.G., OOMMF User's Guide, 1.0, (1999); Hu X., Wu P., Yuan J., Exchange-coupled Fe3O4/L10-FePt bilayer films by controlled oxidation of Fe/Pt multilayer, Thin Solid Films, 517, pp. 2602-2605, (2010); Niedoba H., Labrune M., Magnetic bubbles and stripe domains in nanostructured FePd elements, J. Magn. Magn. Mater., 321, pp. 2178-2186, (2010); Beach G.S.D., Berkowitz A.E., Co-Fe Metal/Native-Oxide Multilayers: A New Direction in Soft Magnetic Thin Film Design I. Quasy-Static Properties and Dynamic Response, IEEE Trans. Magn., 41, (2005); Shima T., Takanashi K., Takahashi Y.K., Hono K., Preparation and magnetic properties of highly coercive FePt fims, Am. Inst. Phys., 81, (2002)","D. Djuhana; Department of Physics, FMIPA Universitas Indonesia, UI Depok, Depok, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","Kartini E.","Institute of Physics Publishing","","19th International Union of Materials Research Societies - International Conference in Asia, IUMRS-ICA 2018","30 October 2018 through 2 November 2018","Bali","155185","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85076089521" +"Anders J.; Sait C.R.J.; Horsley S.A.R.","Anders, J. (16041237900); Sait, C.R.J. (57221145270); Horsley, S.A.R. (8844285200)","16041237900; 57221145270; 8844285200","Quantum Brownian motion for magnets","2022","New Journal of Physics","24","3","033020","","","","24","10.1088/1367-2630/ac4ef2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125168415&doi=10.1088%2f1367-2630%2fac4ef2&partnerID=40&md5=4d94acd8c1698d9c87dba199a78ccf76","Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom; Institut für Physik und Astronomie, University of Potsdam, Potsdam, 14476, Germany","Anders J., Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom, Institut für Physik und Astronomie, University of Potsdam, Potsdam, 14476, Germany; Sait C.R.J., Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom; Horsley S.A.R., Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom","Spin precession in magnetic materials is commonly modelled with the classical phenomenological Landau-Lifshitz-Gilbert (LLG) equation. Based on a quantized three-dimensional spin + environment Hamiltonian, we here derive a spin operator equation of motion that describes precession and includes a general form of damping that consistently accounts for memory, coloured noise and quantum statistics. The LLG equation is recovered as its classical, Ohmic approximation. We further introduce resonant Lorentzian system-reservoir couplings that allow a systematic comparison of dynamics between Ohmic and non-Ohmic regimes. Finally, we simulate the full non-Markovian dynamics of a spin in the semi-classical limit. At low temperatures, our numerical results demonstrate a characteristic reduction and flattening of the steady state spin alignment with an external field, caused by the quantum statistics of the environment. The results provide a powerful framework to explore general three-dimensional dissipation in quantum thermodynamics. © 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.","coloured and quantum noise; LLG equation; magnetisation; memory effects; open quantum systems; quantum thermodynamics; spin dynamics","Brownian movement; Magnetic materials; Mathematical operators; Quantum noise; Quantum optics; Spin dynamics; Statistical mechanics; Thermodynamics; Equation of motion; Landau-Lifshitz-Gilbert equations; Memory effects; Open quantum systems; Operator equation; Quantum Brownian motions; Quantum statistics; Quantum thermodynamics; Spin operators; Spin precession; Equations of motion","","","","","EPSRC Centre for Doctoral Training in Electromagnetic Metamaterials, (EP/L015331/1); TATA, (RPG-2016-186); Engineering and Physical Sciences Research Council, EPSRC, (EP/R045577/1); Royal Society","We thank Karen Livesey, Richard Evans, Marco Berritta, Stefano Scali, Federico Cerisola, Luis Correa, James Cresser, Somayyeh Nemati, Claudia Clarke, Ian Ford and Rob Hicken for inspiring discussions, and Carsten Henkel and Richard Evans for comments on a draft of this manuscript. SARH thanks Paul Kinsler for pointing out the stupidity of numerically solving an integro-differential equation when an ODE will do. SARH also acknowledges funding from the Royal Society and TATA (RPG-2016-186). CRJS and JA acknowledge support and funding from the EPSRC Centre for Doctoral Training in Electromagnetic Metamaterials EP/L015331/1. JA acknowledges funding from EPSRC (EP/R045577/1) and the Royal Society. ","Goold J, Huber M, Riera A, Rio L, Skrzypczyk P, The role of quantum information in thermodynamics-a topical review, J. Phys. A: Math. Theor, 49, (2016); Vinjanampathy S, Anders J, Quantum thermodynamics, Contemp. Phys, 57, (2016); Binder F, Thermodynamics in the Quantum Regime: Fundamental Aspects and New Directions, (2018); Wichterich H, Henrich M J., Breuer H.-P., Gemmer J, Michel M, Modeling heat transport through completely positive maps, Phys. Rev. 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Phys.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85125168415" +"Kaltenbacher B.; Nguyen T.T.N.; Wald A.; Schuster T.","Kaltenbacher, Barbara (6603819218); Nguyen, Tram Thi Ngoc (57214830815); Wald, Anne (57193234771); Schuster, Thomas (56857230100)","6603819218; 57214830815; 57193234771; 56857230100","Parameter identification for the Landau-Lifshitz-Gilbert equation in magnetic particle imaging","2021","Time-dependent Problems in Imaging and Parameter Identification","","","","377","412","35","6","10.1007/978-3-030-57784-1_13","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85108861365&doi=10.1007%2f978-3-030-57784-1_13&partnerID=40&md5=a797db64de9fe989862a9cb9e1a36671","Department of Mathematics, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Austria; Institute of Mathematics and Scientific Computing, University of Graz, Graz, Austria; Department of Mathematics, Saarland University, Saarbrücken, Saarland, Germany","Kaltenbacher B., Department of Mathematics, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Austria; Nguyen T.T.N., Institute of Mathematics and Scientific Computing, University of Graz, Graz, Austria; Wald A., Department of Mathematics, Saarland University, Saarbrücken, Saarland, Germany; Schuster T., Department of Mathematics, Saarland University, Saarbrücken, Saarland, Germany","Magnetic particle imaging (MPI) is a tracer-based technique for medical imaging where the tracer consists of ironoxide nanoparticles. The key idea is to measure the particle response to a temporally changing external magnetic field to compute the spatial concentration of the tracer inside the object. A decent mathematical model demands for a data-driven computation of the system function which does not only describe the measurement geometry but also encodes the interaction of the particles with the external magnetic field. The physical model of this interaction is given by the Landau-Lifshitz-Gilbert (LLG) equation. The determination of the system function can be seen as an inverse problem of its own which can be interpreted as a calibration problem for MPI. In this contribution the calibration problem is formulated as an inverse parameter identification problem for the LLG equation. We give a detailed analysis of the direct as well as the inverse problem in an all-at-once as well as in a reduced setting. The analytical results yield a deeper understanding of inverse problems connected to the LLG equation and provide a starting point for the development of robust numerical solution methods in MPI. © Springer Nature Switzerland AG 2021.","","","","","","","","","Borcea L., Electrical impedance tomography, Inverse Prob, 18, pp. R99-R136, (2002); Bruckner F., Suess D., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Ruggeri M., Multiscale modeling in micromagnetics: Existence of solutions and numerical integration, Math. Models Methods Appl. Sci, 24, pp. 2627-2662, (2014); Colton D., Kress R., Inverse Acoustic and Electromagnetic Scattering Theory, (2013); Croft L.R., Goodwill P.W., Conolly S.M., Relaxation in x-space magnetic particle imaging, IEEE Trans. Med. 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Anal, 54, pp. 2594-2618, (2016); Kaltenbacher B., All-at-once versus reduced iterative methods for time dependent inverse problems, Inverse Prob, 33, (2017); Kaltenbacher B., Neubauer A., Scherzer O., Iterative Regularization Methods for Nonlinear Ill-Posed Problems, (2008); Kaltenbacher B., Schopfer F., Schuster T., Iterative methods for nonlinear ill-posed problems in Banach spaces: Convergence and applications to parameter identification problems, Inverse Prob, 25, (2009); Kirsch A., Rieder A., Inverse problems for abstract evolution equations with applications in electrodynamics and elasticity, Inverse Prob, 32, (2016); Kluth T., Mathematical models for magnetic particle imaging, Inverse Prob, 34, (2018); Kluth T., Maass P., Model uncertainty in magnetic particle imaging: Nonlinear problem formulation and model-based sparse reconstruction, Int. J. Magn. Part. 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Imaging, 10, pp. 1087-1110, (2016); Natterer F., The Mathematics of Computerized Tomography, (1986); Natterer F., Wubbeling F., Mathematical Methods in Image Reconstruction, (2001); Nguyen T.T.N., Landweber-Kaczmarz for parameter identification in time-dependent inverse problems: All-at-once versus reduced version, Inverse Prob, 35, (2019); Reeves D.B., Weaver J.B., Approaches for modeling magnetic nanoparticle dynamics, Critical Rev. Biomed. Eng, 42, pp. 85-93, (2014); Rieder A., On the regularization of nonlinear ill-posed problems via inexact Newton iterations, Inverse Prob, 15, pp. 309-327, (1999); Roubicek T., Nonlinear Partial Differential Equations with Applications, (2013); Schuster T., Kaltenbacher B., Hofmann B., Kazimierski K., Regularization Methods in Banach Spaces, (2012); Shepp L., Vardi Y., Maximum likelihood reconstruction for emission tomography, IEEE Trans. Med. Imag, 1, pp. 113-122, (1982); Wald A., Schuster T., Sequential subspace optimization for nonlinear inverse problems, J. Inverse Ill-posed Prob, 25, pp. 99-117, (2016); Wald A., Schuster T., Tomographic terahertz imaging using sequential subspace optimization, New Trends in Parameter Identification for Mathematical Models, (2018)","A. Wald; Department of Mathematics, Saarland University, Saarbrücken, Saarland, Germany; email: anne.wald@num.uni-sb.de","","Springer International Publishing","","","","","","","978-303057784-1; 978-303057783-4","","","English","Time-dependent Probl. in Imaging and Parameter Identif.","Book chapter","Final","","Scopus","2-s2.0-85108861365" +"Li H.; Nikonov D.E.; Lin C.-C.; Camsari K.; Liao Y.-C.; Hsu C.-S.; Naeemi A.; Young I.A.","Li, Hai (57190068298); Nikonov, Dmitri E. (7003272404); Lin, Chia-Ching (57204788945); Camsari, Kerem (56682099700); Liao, Yu-Ching (57217100462); Hsu, Chia-Sheng (57201436153); Naeemi, Azad (6602173751); Young, Ian A. (7402362397)","57190068298; 7003272404; 57204788945; 56682099700; 57217100462; 57201436153; 6602173751; 7402362397","Physics-Based Models for Magneto-Electric Spin-Orbit Logic Circuits","2022","IEEE Journal on Exploratory Solid-State Computational Devices and Circuits","8","1","","10","18","8","8","10.1109/JXCDC.2022.3143130","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85123287714&doi=10.1109%2fJXCDC.2022.3143130&partnerID=40&md5=740daf7e050746d6fe10cdde56c024a7","Components Research, Intel Corporation, Hillsboro, 97124, OR, United States; Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, 93106, CA, United States; Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, 30332, GA, United States","Li H., Components Research, Intel Corporation, Hillsboro, 97124, OR, United States; Nikonov D.E., Components Research, Intel Corporation, Hillsboro, 97124, OR, United States; Lin C.-C., Components Research, Intel Corporation, Hillsboro, 97124, OR, United States; Camsari K., Department of Electrical and Computer Engineering, University of California at Santa Barbara, Santa Barbara, 93106, CA, United States; Liao Y.-C., Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, 30332, GA, United States; Hsu C.-S., Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, 30332, GA, United States; Naeemi A., Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, 30332, GA, United States; Young I.A., Components Research, Intel Corporation, Hillsboro, 97124, OR, United States","Spintronic devices provide a promising beyond-complementary metal-oxide-semiconductor (CMOS) device option, thanks to their energy efficiency and compatibility with CMOS. To accurately capture their multiphysics dynamics, a rigorous treatment of both spin and charge and their inter-conversion is required. Here, we present physics-based device models based on 4×4 matrices for the spin-orbit coupling (SOC) part of the magneto-electric spin-orbit (MESO) device. Also, a more rigorous physics model of ferroelectric and magnetoelectric (ME) switching of ferromagnets, based on Landau-Lifshitz-Gilbert (LLG) and Landau-Khalatnikov (LK) equations, are presented. With the combined model implemented in a SPICE circuit simulator environment, simulation results were obtained which show feasibility of the MESO implementation and the functional operation of buffers, synchronous oscillators, and majority gates. © 2014 IEEE.","Beyond complementary metal-oxide-semiconductor (CMOS) logic; magnetoelectric (ME); SPICE; spin-orbit (SO); spintronic devices","CMOS integrated circuits; Computer circuits; Energy efficiency; Frequency modulation; Logic circuits; Magnetic circuits; Oscillators (electronic); Spin dynamics; Spintronics; Timing circuits; 'spice'; Beyond CMOS; Beyond CMOS logic; CMOS devices; CMOS logic; Integrated circuit modeling; Magnetoelectrics; Physics-based models; Spin orbits; Spintronics device; SPICE","","","","","","","Moore G.E., Cramming more components onto integrated circuits, Proc. IEEE, 86, 1, pp. 82-85, (1998); Holt W.M., Moore's law: A path going forward, IEEE ISSCC Dig. Tech. Papers, 59, pp. 8-13, (2016); Gelsinger P.P., Microprocessors for the new millennium: Challenges, opportunities, and new frontiers, IEEE ISSCC Dig. Tech. Papers, pp. 22-25, (2001); Nikonov D.E., Young I.A., Benchmarking delay and energy of neural inference circuits, IEEE J. Explor. Solid-State Comput. Devices Circuits, 5, pp. 75-84, (2019); Behin-Aein B., Datta D., Salahuddin S., Datta S., Proposal for an all-spin logic device with built-in memory, Nature Nanotechnol., 5, 4, pp. 266-270, (2010); Behin-Aein B., Sarkar A., Srinivasan S., Datta S., Switching energy-delay of all spin logic devices, Appl. Phys. Lett., 98, 12, (2011); Manipatruni S., Nikonov D.E., Young I.A., Modeling and design of spintronic integrated circuits, IEEE Trans. Circuits Syst. I, Reg. Papers, 59, 12, pp. 2801-2814, (2012); Camsari K.Y., Ganguly S., Datta S., Modular approach to spintron-ics, Sci. Rep., 5, 1, pp. 1-13, (2015); Ganguly S., Camsari K.Y., Datta S., Evaluating spintronic devices using the modular approach, IEEE J. Explor. Solid-State Comput. Devices Circuits, 2, pp. 51-60, (2016); Manipatruni S., Et al., Scalable energy-ef_cient magnetoelectric spin-orbit logic, Nature, 565, 7737, pp. 35-42, (2018); Liu H., Et al., Synchronous circuit design with beyond-CMOS magneto-electric spin-orbit devices toward 100-mV logic, IEEE J. Explor. Solid-State Comput. Devices Circuits, 5, pp. 1-9, (2019); Mankalale M.G., Liang Z., Zhao Z., Kim C.H., Wang J.P., Sapatnekar S.S., CoMET: Composite-input magnetoelectric-based logic technology, IEEE J. Explor. Solid-State Computat. Devices Circuits, 3, pp. 27-36, (2017); Dowben P.A., Nikonov D.E., Marshall A., Binek C., Magneto-electric antiferromagnetic spin-orbit logic devices, Appl. Phys. Lett., 116, 8, (2020); Afuye O., Et al., Modeling and circuit design of associative memories with spin-orbit torque FETs, IEEE J. Explor. Solid-State Comput. Devices Circuits, 5, pp. 197-205, (2019); Li H., Lin C.-C., Nikonov D.E., Young I.A., Differential electrically insulated magnetoelectric spin-orbit logic circuits, IEEE J. Explor. Solid-State Comput. Devices Circuits, 7, pp. 18-25, (2021); Liao Y.-C., Et al., Understanding the switching mechanisms of the anti-ferromagnet/ferromagnet heterojunction, Nano Lett., 20, 11, pp. 7919-7926, (2020); Liao Y.-C., Et al., Evaluating the performances of the ultra-low power magnetoelectric random-access memory with a physics-based compact model of the antiferromagnet/ferromagnet bilayer, IEEE Trans. Electron Devices, (2021); Heron J.T., Et al., Deterministic switching of ferromagnetism at room temperature using an electric _eld, Nature, 516, 7531, pp. 370-373, (2014); Dzyaloshinsky I.E., Thermodynamic theory of weak' ferromagnetism in antiferromagnetic substances, Sov. Phys. Jetp-Ussr, 5, 6, pp. 1259-1272, (1957); Moriya T., Anisotropic superexchange interaction and weak ferromag-netism, Phys. Rev., 120, 1, pp. 91-98, (1960); Gilbert T.L., Classics in magnetics a phenomenological theory of damp-ing in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Hong S., Sayed S., Datta S., Spin circuit representation for the spin Hall effect, IEEE Trans. Nanotechnol., 15, 2, pp. 225-236, (2016); Hoffmann A., Spin Hall effects in metals, IEEE Trans. Magn., 49, 10, pp. 5172-5193, (2013); Du Y., Gamou H., Takahashi S., Karube S., Kohda M., Nitta J., Disentanglement of spin-orbit torques in Pt/Co bilayers with the presence of spin Hall effect and Rashba-Edelstein effect, Phys. Rev. A, Gen. Phys., 13, 5, pp. 34-37, (2020); Brataas A., Bauer G.E.W., Kelly P.J., Non-collinear magnetoelec-tronics, Phys. Rep., 427, 4, pp. 157-255, (2006); Khan A.I., Et al., Negative capacitance in a ferroelectric capacitor, Nature Mater., 14, 2, pp. 182-186, (2015); Dc M., Et al., Room-temperature high spin-orbit torque due to quantum confinement in sputtered BixSe(1x) films, Nature Mater., 17, 9, pp. 800-807, (2018)","H. Li; Components Research, Intel Corporation, Hillsboro, 97124, United States; email: hai.li@intel.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","23299231","","","","English","IEEE Explor. Solid State Comput. Devices Circuits","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85123287714" +"Wang M.; Jiang Y.","Wang, Manman (57221832033); Jiang, Yanfeng (17436165500)","57221832033; 17436165500","Compact Model of Domain Wall MTJ Driven by Spin Orbit Torque and Dzyaloshinskii-Moriya Interaction","2022","IEEE Transactions on Magnetics","58","8","1300805","","","","5","10.1109/TMAG.2021.3138191","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85122063227&doi=10.1109%2fTMAG.2021.3138191&partnerID=40&md5=ae38ad040170ee50004947ac0e2707f4","Jiangnan University, School of Internet of Things Engineering, Department of Electrical Engineering, Wuxi, 214122, China","Wang M., Jiangnan University, School of Internet of Things Engineering, Department of Electrical Engineering, Wuxi, 214122, China; Jiang Y., Jiangnan University, School of Internet of Things Engineering, Department of Electrical Engineering, Wuxi, 214122, China","Current-induced domain wall motion (CIDWM) shows promising prospects with low power, high density, high speed, and so on. Recent studies have demonstrated that magnetic tunnel junction (MTJ) based on CIDWM has great potential in mimicking a non-volatile artificial neuron and synapse. By combining the effect of the interfacial Dzyaloshinskii-Moriya interaction (DMI) to stabilize the Néel-type domain wall (DW) and the high-speed low-power advantages of spin orbit torque (SOT), the novel MTJ device is experimentally demonstrated with low threshold current and high propagation speed, which shows potential applications in the field of the artificial neuron and synapse. In this article, a compact model for CIDWM-MTJ based on SOT and DMI is presented. The model integrates the SOT mechanism for magnetization reversal and DW nucleation, CIDWM behaviors, and tunnel resistance theory of MTJ nanopillar. The micromagnetic simulation and the temporal evolution of the DW position are implemented by solving the Landau-Lifshitz-Gilbert (LLG) equation and the 1-D model. Based on the developed model, a hybrid CIDWM-MTJ/CMOS circuit is simulated for verification. The presented model combines the CIDWM dynamics and the MTJ magnetic dynamics, showing potential application for the simulation of all-spin artificial neural network (ANN). © 1965-2012 IEEE.","Domain wall (DW); magnetic tunnel junction (MTJ); spin-orbit torque (SOT); spintronics","Circuit simulation; Domain walls; Integrated circuits; Magnetic anisotropy; Magnetic devices; Magnetization reversal; Neural networks; Spin dynamics; Timing circuits; Tunnel junctions; Current-induced domain wall motions; Domain wall; Integrated circuit modeling; Magnetic tunnel junction; Magnetic tunneling; Perpendicular magnetic anisotropy; Spin orbits; Spin-orbit torque; Strip; Torque","","","","","","","Wang C., Wang Z., Wang M., Zhang X., Zhang Y., Zhao W., Compact model of Dzyaloshinskii domain wall motion-based MTJ for spin neural networks, IEEE Trans. Electron Devices, 67, 6, pp. 2621-2626, (2020); Zhao W.S., Duval J., Ravelosona D., Klein J.-O., Kim J.V., Chappert C., A compact model of domain wall propagation for logic and memory design, J. Appl. Phys., 109, 7, (2011); Nasseri S.A., Martinez E., Durin G., Collective coordinate descriptions of magnetic domain wall motion in perpendicularly magnetized nanostructures under the application of in-plane fields, J. Magn. Magn. Mater., 468, pp. 25-43, (2018); Fukami S., Suzuki T., Nagahara K., Ohshima N., Sugibayashi T., Low-current perpendicular domain wall motion cell for scalable highspeed MRAM, Proc. Symp. VLSI Technol., pp. 230-231, (2009); Khvalkovskiy A.V., Et al., Matching domain-wall configuration and spin-orbit torques for efficient domain-wall motion, Phys. Rev. B, Condens. Matter, 87, 2, (2013); Zhao X., Et al., Ultra-efficient spin-orbit torque induced magnetic switching in W/CoFeB/MgO structures, Nanotechnology, 30, 33, (2019); Ryu K.-S., Thomas L., Yang S.H., Parkin S., Chiral spin torque at magnetic domain walls, Nature Nanotechnol., 8, 7, pp. 527-533, (2013); Sengupta A., Shim Y., Roy K., Proposal for an all-spin artificial neural network: Emulating neural and synaptic functionalities through domain wall motion in ferromagnets, IEEE Trans. Biomed. Circuits Syst., 10, 6, pp. 1152-1160, (2016); Cui C., Et al., Maximized lateral inhibition in paired magnetic domain wall racetracks for neuromorphic computing, Nanotechnology, 31, 29, (2020); Bennett C.H., Xiao T.P., Cui C., Hassan N., Marinella M.J., Plasticity-enhanced domain-wall MTJ neural networks for energyefficient online learning, Proc. IEEE Int. Symp. Circuits Syst. (ISCAS), pp. 1-5, (2020); Emori S., Bauer U., Ahn S.-M., Martinez E., Beach G.S.D., Current-driven dynamics of chiral ferromagnetic domain walls, Nature Mater., 12, 7, pp. 611-616, (2013); Martinez E., Emori S., Perez N., Torres L., Beach G., Currentdriven dynamics of Dzyaloshinskii domain walls in the presence of inplane fields: Full micromagnetic and one-dimensional analysis, J. Appl. Phys., 115, 21, (2014); Vatankhahghadim A., Huda S., Sheikholeslami A., A survey on circuit modeling of spin-transfer-torque magnetic tunnel junctions, IEEE Trans. Circuits Syst. I, Reg. Papers, 61, 9, pp. 2634-2643, (2014); Wang M., Et al., Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin-orbit and spin-transfer torques, Nature Electron., 1, 11, pp. 582-588, (2018); Wang M., Jiang Y., Compact model of nanometer STT-MTJ device with scale effect, AIP Adv., 11, 2, (2021); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, 5, pp. 1677-1686, (1963); Wang M., Jiang Y., Modeling of single-digit nanometer perpendicular shape anisotropy magnetic tunnel junction driven by spin-transfertorque, Proc. IEEE Int. Magn. Conf. (INTERMAG), pp. 1-5, (2021); Mougin A., Cormier M., Adam J.P., Metaxas P.J., Ferre J., Domain wall mobility, stability and Walker breakdown in magnetic nanowires, Europhys. Lett., 78, 5, (2007); Thiaville A., Rohart S., Jue E., Cros V., Fert A., Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films, Europhys. Lett., 100, 5, pp. 2611-2625, (2012)","Y. Jiang; Jiangnan University, School of Internet of Things Engineering, Department of Electrical Engineering, Wuxi, 214122, China; email: jiangyf@jiangnan.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85122063227" +"Hawibowo S.; Kurniawan C.; Djuhana D.","Hawibowo, Sulaiman (57217930469); Kurniawan, Candra (55600299500); Djuhana, Dede (26027849100)","57217930469; 55600299500; 26027849100","Study of domain wall propagation in fept and fepd nanowires driven by sub-nanosecond pulse of magnetic field by micromagnetic simulation","2019","IOP Conference Series: Materials Science and Engineering","553","1","012017","","","","1","10.1088/1757-899X/553/1/012017","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85076114428&doi=10.1088%2f1757-899X%2f553%2f1%2f012017&partnerID=40&md5=1c3b39174a090e037e1cb313f5e28a13","Department of Physics, Faculty of Mathematics and Natural Science Universitas Indonesia, Depok, 1624, Indonesia; Research Centre for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area, Tangerang Selatan, 15314, Indonesia","Hawibowo S., Department of Physics, Faculty of Mathematics and Natural Science Universitas Indonesia, Depok, 1624, Indonesia; Kurniawan C., Department of Physics, Faculty of Mathematics and Natural Science Universitas Indonesia, Depok, 1624, Indonesia, Research Centre for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area, Tangerang Selatan, 15314, Indonesia; Djuhana D., Department of Physics, Faculty of Mathematics and Natural Science Universitas Indonesia, Depok, 1624, Indonesia","In this study, we investigated the domain wall propagation behavior in FePt and FePd nanowires by micromagnetic simulation based on LLG equation. A rectangular shape nanowire model was generated with a fixed length of 2000 nm and varied thicknesses of 2.5 nm and 5 nm. The wire widths were varied of 50 nm, 100 nm, and 150 nm. The 500 ps length of magnetic-pulse was applied in-plane to a transverse type domain wall. We observed the Walker Breakdown field (H WB), which means the maximum domain wall velocity before it was abruptly decreased. The transverse DW structure was maintained below H WB while vortex/antivortex wall structure was formed in the higher magnetic field. Interestingly, the H WB value of both FePt and FePd were decreased as the width and thickness of the nanowires increased. We have also analyzed the changing of the demagnetization and exchange energy for the domain wall structure transition from transverse wall to vortex/anti-vortex wall. © Published under licence by IOP Publishing Ltd.","domain wall; micromagnetic; nanowire; transverse wall; vortex wall; Walker Breakdown","Binary alloys; Magnetic fields; Magnetic logic devices; Nanowires; Vortex flow; Domain wall structures; Domain wall velocities; Domain-wall propagation; Micromagnetic simulations; Micromagnetics; Sub-nanosecond pulse; Transverse walls; Vortex walls; Domain walls","","","","","Indexed International Publication","This work is supported by Indexed International Publication Grant (Publikasi Internasional Terindeks, PIT 9) year 2019 No. NKB-0023/UN2.R3.1/HKP.05.00/2019 through DRPM Universitas Indonesia.","Sousa R.C., Prejbeanu I.L., Non-volatile magnetic random access memories (MRAM), C.R. Physique, 6, (2005); Baibich M.N., Broto J.M., Fert A., Nguyen Van Dau F., Petroff F., Giant magnetoresistance of Fe/Cr magnetic superlattice, Phys. Rev. Lett., 61, (1988); Binasch G., Grnber P., Saurenbach F., Zinn W., Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange, Phys Rev B, 39, (1989); Parkin S.S.P., Hayashi M., Thomas L., Magnetic Domain-Wall Racetrack Memory, Science, 320, pp. 190-194, (2008); Parkin S.S.P., Data in the Fast Lanes of Racetrack Memory, Sci. Am., 300, pp. 76-81, (2009); Michael R.D., Donahue M.J., Head to head domain wall structures in thin magnetic strips, IEEE Trans. Magn., 33, (1997); Nakatani Y., Thiaville A., Miltat J.J., Determination of Domain Wall Depinning and Driving Currents in Doped Permalloy Structures, Magn. Mag. Matter., 290, (2005); Tudu B., Tiwari A., Recent developments in Perpendicular Magnetic Anisotropy Thin Films for Data Storage Applications, Vacuum, 146, pp. 329-341, (2017); Ovanov O.A., Solina L.V., Demshina V.A., Phys. Met. Mettallogr, 35, (1973); Shima T., Takanashi K., Hono K., Preparation and magnetic properties of highly coercive FePt films, Appl. Phys. Lett., 81, (2002); Bi M., Wang X., Lu H., Zhang L., Deng L., Xie J., Thickness Dependence of Magnetization Reversal Mechanism in Perpendicularly Magnetized L10 FePt Films, 428, pp. 412-416, (2017); Skuza J.R., Clavero C., Yang K., Wincheski B., Lukaszew R.A., Microstructural, Magnetic Anisotropy, and Magnetic Domain Structure Correlations in Epitaxial FePd Thin Films with Perpendicular Magnetic Anisotropy, IEEE Trans. Magn., 46, pp. 1886-1889, (2010); Skomski R., Kashyap A., Zhou J., Scr. Mater., 53, pp. 389-394, (2005); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 1.0, (1999); Gilbert T.L., Classics in Magnetics a Phenomenological Theory of Damping in Ferromagnetic Materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Hu X., Wu P., Yuan J., Exchange-coupled Fe3O4/L10-FePt bilayer films by controlled oxidation of Fe/Pt multilayer, Thin Solid Films, 517, pp. 2602-2605, (2009); Niedoba H., Labrune M., Magnetic bubbles and stripe domains in nanostructured FePd elements, Journal of Magnetism and Magnetic Materials, 321, pp. 2178-2186, (2009); Djuhana D., Piao H.-G., Shim J.-H., Lee S.-H., Ahn S.-M., Kim D.-H., Interaction of antiparallel transverse domain walls in ferromagnetic nanowire, J. Nanosci. Nanotechnol., 10, pp. 6237-6240, (2011); Schryer N.L., Walker L.R., The motion of 180° domain walls in uniform dc magnetic field, J Appl Phys, 45, (1974); Nakatani Y., Thiaville A., Miltat J., Head to head domain walls in nano-strips: A refined phase diagram, J. Magn. Magn Mater., 290, (2005)","D. Djuhana; Department of Physics, Faculty of Mathematics and Natural Science Universitas Indonesia, Depok, 1624, Indonesia; email: dede.djuhana@sci.ui.ac.id","Kartini E.","Institute of Physics Publishing","","19th International Union of Materials Research Societies - International Conference in Asia, IUMRS-ICA 2018","30 October 2018 through 2 November 2018","Bali","155185","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85076114428" +"Kang D.H.; Byun J.-H.; Shin M.","Kang, Doo Hyung (8653973000); Byun, Ji-Hun (57219955831); Shin, Mincheol (7401536683)","8653973000; 57219955831; 7401536683","Critical switching current of a perpendicular magnetic tunnel junction owing to the interplay of spin-transfer torque and spin-orbit torque","2021","Journal of Physics D: Applied Physics","54","43","435001","","","","2","10.1088/1361-6463/ac181a","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85113451351&doi=10.1088%2f1361-6463%2fac181a&partnerID=40&md5=6fcc96292bba01da9fbfe799afb2907f","School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea","Kang D.H., School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea; Byun J.-H., School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea; Shin M., School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea","Using the linearized Landau-Lifshitz-Gilbert (LLG) equation in the rotation coordinate, we calculate the critical switching current density of a perpendicular magnetic tunnel junction (MTJ), where magnetization switching is achieved by the interplay of spin-transfer and spin-orbit torques. In terms of the critical current density, we find that as the current density inducing the spin-orbit torque (jSOT) increases, the current density inducing the spin-transfer torque (jSTT) decreases nonlinearly. In the presence of the spin-orbit field-like torque (β), the critical switching current density by the spin-transfer torque is proportional to the damping constant (α) as the conventional spin-transfer torque switching, while the critical switching current density by the spin-orbit torque increases with √α when Heff ≫ HSOT. We also investigated the β dependence of the critical switching current density. For a given jSOT, the critical switching current density for the spin-transfer torque, jSTT,c decreases linearly with increasing β and nonlinearly decreases with increasing jSOT for a given β. Further, we discuss the β dependence of the critical switching current density on energy. © 2021 IOP Publishing Ltd.","critical current density; spin orbit torque; spin transfer torque","Current density; Magnetization; Spin orbit coupling; Switching; Torque; Tunnel junctions; Critical switching current; Damping constants; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Magnetization switching; Spin orbit field; Spin transfer torque; Spin transfer torque switching; Magnetic devices","","","","","","","Ikeda S, Et al., Nat. Mater, 9, (2010); Thomas L, Et al., J. Appl. Phys, 115, (2014); Kent A D, Worledge D C, Nat. Nanotechnol, 10, (2015); Hu G, Et al., Int. Electron Devices Meet. (IEDM), 26, (2015); Hosomi M, Et al., Int. Electron Devices Meet. (IEDM) Technical Digest, (2005); Wang X, Et al., Appl. Phys. Express, 7, (2014); Wang Z, Li Z, Wang M, Wu B, Zhu D, Zhao W, Nanotechnology, 30, (2019); Hei R, Rippard W H, Russek S E, Kos A B, Phys. Rev. B, 83, (2011); Hahn C, Wolf G, Kardasz B, Watts S, Pinarbasi M, Kent A D, Phys. Rev. B, 94, (2016); Hirsch J E, Phys. Rev. Lett, 83, (1999); Miron I M, Et al., Nature, 476, (2011); Liu L, Lee O J, Gudmundsen T J, Ralph D C, Buhrman R A, Phys. Rev. Lett, 109, (2012); Yu G, Et al., Nat. Nanotechnol, 9, (2014); Lee D, Lee K, Sci. Rep, 10, (2020); Liu L, Pai C, Li Y, Tseng H W, Ralph D C, Buhrman R A, Science, 336, (2012); You L, Lee O, Bhowmik D, Labanowski D, Hong J, Bokor J, Salahuddin S, Proc. Natl Acad. Sci, 112, (2015); Fukami S, Zhang C, Gupta S D, Kurenkov A, Ohno H, Nat. Mater, 15, (2016); Lau Y, Betto D, Rode K, Coey J D M, Stamenov P, Nat. Nanotechnol, 11, (2016); Oh Y, Et al., Nat. Nanotechnol, 11, (2016); van den Brink A, Vermijs G, Solignac A, Koo J, Kohlhepp J T, Swagten H J M, Koopmans B, Nat. Commun, 7, (2016); Cai K, Et al., Nat. Mater, 16, (2017); Lee K, Lee S, Min B, Lee K, Appl. Phys. Lett, 102, (2013); Taniguchi T, Phys. Rev. B, 100, (2019); Daoqian Z, Weisheng Z, Phys. Rev. Appl, 13, (2020); Wang Z, Zhao W, Deng E, Klein J, Chappert C, J. Phys. D: Appl. Phys, 48, (2015); Gao Y, Wang Z, Lin X, Kang W, Zhang Y, Zhao W, IEEE Trans. Nanotechnol, 16, (2017); Wang M, Et al., Nat. Electron, 1, (2018); Pathak S, Youm C, Hong J, Sci. Rep, 10, (2020); Byun J, Kang D H, Shin M, AIP Adv, 11, (2021); Sun J Z, Et al., Phys. Rev. B, 84, (2011); Park J, Rowlands G E, Lee O J, Ralph D C, Buhrman R A, Appl. Phys. Lett, 105, (2014); Taniguchi T, Mitani S, Hayashi M, Phys. Rev. B, 92, (2015); Taniguchi T, Kubota H, Phys. Rev. B, 93, (2016); Mangin S, Ravelosona D, Katine J A, Carey M J, Terris B D, Fullerton E E, Nat. Mater, 5, (2006); Gar K, Et al., Nat. Nanotech, 8, (2013); Qiu X, Et al., Sci. Rep, 4, (2014)","D.H. Kang; School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea; email: ppassionata@kaist.ac.kr; M. Shin; School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, South Korea; email: mshin@kaist.ac.kr","","IOP Publishing Ltd","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","","Scopus","2-s2.0-85113451351" +"Wang M.; Jiang Y.","Wang, Manman (57221832033); Jiang, Yanfeng (17436165500)","57221832033; 17436165500","Modeling of Single-Digit Nanometer Perpendicular Shape Anisotropy Magnetic Tunnel Junction Driven by Spin-Transfer-Torque","2021","Digests of the Intermag Conference","2021-April","","","","","","2","10.1109/INTERMAG42984.2021.9579780","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125962065&doi=10.1109%2fINTERMAG42984.2021.9579780&partnerID=40&md5=b992ecc02d2fed2033eb408ca3a49bd4","School of Internet of Things Engineering, Jiangnan University, No. 1800 Lihu Avenue, Wuxi, 214122, China","Wang M., School of Internet of Things Engineering, Jiangnan University, No. 1800 Lihu Avenue, Wuxi, 214122, China; Jiang Y., School of Internet of Things Engineering, Jiangnan University, No. 1800 Lihu Avenue, Wuxi, 214122, China","Spin Transfer Torque Magnetic Random-Access Memory (STT-MRAM) has become one of the leading candidates for next generation memory applications. One of the key challenges is the simultaneous achievement of low switching current, high thermal stability and large TMR. Low switching current can be achieved by the shrinkage of the device size. However, the thermal stability of the perpendicular magnetic tunnel junction (P-MTJ) is severely damaged with the reduced size. The concept of Perpendicular Shape Anisotropy (PSA) MTJ is proposed recently, in which thicker free layer is adopted to keep the required thermal stability in single-digit nanometers. In this way, relative high thermal stability can be achieved even the size down to sub-10-nm. The device shows possible application in the nanometer scale and is compatible with the developed CMOS technology nodes. The SPICE model of the PSA-MTJ device is highly required since its operation principle is different from the incumbent STT-MTJ device. In this paper, a dynamic model of the PSA-MTJ is developed, including its micromagnetic simulation using LLG equation. In the developed model, the stochastic term is included to denote the effects in nanometer scale. In this way, the accuracy is improved. By analyzing the instantaneous magnetization vector, the switching time is extracted. The impacts of the write voltage scaling on the switching time, the energy consumption and the write failure rate of PSA-MTJ are studied. Based on the model, both the static and dynamic behaviors can be simulated. The scale effect of the PMA device is also studied based on the developed model. Finally, hybrid MTJ/CMOS simulation is performed to validate the developed model for circuit designs and simulations in the single-digit nanometer scale. © 2021 IEEE.","Magnetic tunnel junction (MTJ); Perpendicular shape anisotropy (PSA); STT-MRAM","Failure analysis; Hysteresis; Integrated circuit manufacture; Magnetic anisotropy; Magnetic recording; Magnetism; MRAM devices; Stochastic models; Stochastic systems; Switching; Thermodynamic stability; Tunnel junctions; Voltage scaling; Anisotropy-magnetic; Developed model; Magnetic random access memory; Magnetic tunnel junction; Nano-meter-scale; Perpendicular shape anisotropy; Shape anisotropy; Spin transfer torque; Spin transfer torque magnetic random-access memory; Energy utilization","","","","","National Natural Science Foundation of China, NSFC, (61774078)","ACKNOWLEDGMENT This work was supported by NSFC (No.61774078).","Ikegawa S., Mancoff F.B., Janesky J., Aggarwal S., Magnetoresistive random access memory: Present and future, IEEE Transactions on Electron Devices, 67, 4, pp. 1407-1419, (2020); Apalkov D., Dieny B., Slaughter J., Magnetoresistive random access memory, Proceedings of the IEEE, 104, 10, pp. 1796-1830, (2016); Current-induced magnetization reversal in nanopillars with perpendicular anisotropy, Nature Materials, 5, 3, pp. 210-215, (2006); Ghosh B., Dwivedi K., Micromagnetic analysis of a double-barrier synthetic antiferromagnetic MTJ stack, Applied Nanoscience, 5, 7, pp. 771-775, (2015); Watanabe K., Jinnai B., Fukami S., Sato H., Ohno H., Shape anisotropy revisited in single-digit nanometer magnetic tunnel junctions, Nat Commun, 9, 1, (2018); Perrissin N., Et al., A highly thermally stable sub-20 nm magnetic random-access memory based on perpendicular shape anisotropy, Nanoscale, 10, 25, pp. 12187-12195, (2018); Sato H., Amanouchi M.Y., Ikeda S., Fukami S., Matsukura F., Ohno H., Perpendicular-anisotropy CoFeB-MgO magnetic tunnel junctions with a MgO/CoFeB/Ta/CoFeB/MgO recording structure, Applied Physics Letters, (2012); Osborn J.A., Demagnetizing factors of the general ellipsoid, Physical Review, 67, 11-12, pp. 351-357, (1945); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, 1-2, pp. L1-L7, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Physical Review B Condensed Matter, 54, 13, (1996); Gilbert T.L., A lagrangian formulation of the gyromagnetic equation of the magnetic field, Physical Review, 100, 52, (1955); Landau L., Lifshitz E., On the Theory of the Dispersion of Magnetic Permeability in Ferromagnetic Bodies. Reproduced in Collected Papers of LD Landau, (1935); Wang G., Yue Z., Zhang Z., Jiang N., Zhao W., Compact modeling of high spin transfer torque efficiency double-barrier magnetic tunnel junction, Proc. 13th NANOARCH, Newport, RI, USA, pp. 49-54; Brown W.F., Thermal fluctuations of a single-domain particle, Physical Review, 130, 5, pp. 1677-1686, (1963); Vatankhahghadim A., Huda S., Sheikholeslami A., A survey on circuit modeling of spin-transfer-torque magnetic tunnel junctions, IEEE Transactions on Circuits and Systems I: Regular Papers, 61, 9, pp. 2634-2643, (2014); Wang M., Et al., Field-free switching of a perpendicular magnetic tunnel junction through the interplay of spin-orbit and spin-transfer torques, Nature Electronics, (2018); Wang H., Kang W., Zhang Y., Zhao W., Modeling and evaluation of sub-10-nm shape perpendicular magnetic anisotropy magnetic tunnel junctions, IEEE Transactions on Electron Devices, 65, 12, pp. 5537-55444, (2018); Zhang Y., Et al., Compact modeling of perpendicular-anisotropy CoFeB/MgO magnetic tunnel junctions, IEEE Transactions on Electron Devices, 59, 3, pp. 819-826, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Magnetics Society","2021 IEEE International Magnetic Conference, INTERMAG 2021","26 April 2021 through 30 April 2021","Virtual, Online","177034","00746843","978-073813099-6","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-85125962065" +"Li P.; Yang L.; Lan J.; Du R.; Chen J.","Li, Panchi (57211560785); Yang, Lei (59043156600); Lan, Jin (36052042200); Du, Rui (56763448500); Chen, Jingrun (57219146828)","57211560785; 59043156600; 36052042200; 56763448500; 57219146828","A Second-Order Semi-Implicit Method for the Inertial Landau-Lifshitz-Gilbert Equation","2022","Numerical Mathematics","16","1","","182","203","21","5","10.4208/nmtma.OA-2022-0080","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85151848635&doi=10.4208%2fnmtma.OA-2022-0080&partnerID=40&md5=f4ce7e1f335ed283ce00da94153859da","School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; School of Computer Science and Engineering, Macau University of Science and Technology, Macao, Macao; Center for Joint Quantum Studies, Department of Physics, School of Science, Tianjin University, 92 Weijin Road, Tianjin, 300072, China; Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China","Li P., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Yang L., School of Computer Science and Engineering, Macau University of Science and Technology, Macao, Macao; Lan J., Center for Joint Quantum Studies, Department of Physics, School of Science, Tianjin University, 92 Weijin Road, Tianjin, 300072, China; Du R., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; Chen J., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China, Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China, School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China","Electron spins in magnetic materials have preferred orientations collectively and generate the macroscopic magnetization. Its dynamics spans over a wide range of timescales from femtosecond to picosecond, and then to nanosecond. The Landau-Lifshitz-Gilbert (LLG) equation has been widely used in micromagnetics simulations over decades. Recent theoretical and experimental advances have shown that the inertia of magnetization emerges at sub-picosecond timescales and contributes significantly to the ultrafast magnetization dynamics, which cannot be captured intrinsically by the LLG equation. Therefore, as a generalization, the inertial LLG (iLLG) equation is proposed to model the ultrafast magnetization dynamics. Mathematically, the LLG equation is a nonlinear system of parabolic type with (possible) degeneracy. However, the iLLG equation is a nonlinear system of mixed hyperbolic-parabolic type with degeneracy, and exhibits more complicated structures. It behaves as a hyperbolic system at sub-picosecond timescales, while behaves as a parabolic system at larger timescales spanning from picosecond to nanosecond. Such hybrid behaviors impose additional difficulties on designing efficient numerical methods for the iLLG equation. In this work, we propose a second-order semi-implicit scheme to solve the iLLG equation. The second-order temporal derivative of magnetization is approximated by the standard centered difference scheme, and the first-order temporal derivative is approximated by the midpoint scheme involving three time steps. The nonlinear terms are treated semi-implicitly using one-sided interpolation with second-order accuracy. At each time step, the unconditionally unique solvability of the unsymmetric linear system is proved with detailed discussions on the condition number. Numerically, the second-order accuracy of the proposed method in both time and space is verified. At sub-picosecond timescales, the inertial effect of ferromagnetics is observed in micromagnetics simulations, in consistency with the hyperbolic property of the iLLG model; at nanosecond timescales, the results of the iLLG model are in nice agreements with those of the LLG model, in consistency with the parabolic feature of the iLLG model. ©2023 Global-Science Press.","Inertial Landau-Lifshitz-Gilbert equation; micromagnetics simulations; second-order accuracy; semi-implicit scheme","","","","","","Macau, (0070/2019/A2); Postgraduate Research & Practice Innovation Program of Jiangsu Province, (KYCX20 2711); Shanghai Science and Technology Development Foundation; National Natural Science Foundation of China, NSFC, (11701598, 11904260); National Natural Science Foundation of China, NSFC; Natural Science Foundation of Tianjin City, (11501399, 11971021, 20JCQNJC02020); Natural Science Foundation of Tianjin City","P. Li is supported by the Postgraduate Research & Practice Innovation Program of Jiangsu Province (Grant No. KYCX20 2711). L. Yang is supported by the Science and Technology Development Fund, Macau SAR (Grant No. 0070/2019/A2) and the National Natural Science Foundation of China (NSFC) (Grant No. 11701598). J. Lan is supported by NSFC (Grant No. 11904260) and the Natural Science Foundation of Tianjin (Grant No. 20JCQNJC02020). R. Du was supported by NSFC (Grant No. 11501399). J. Chen is supported by NSFC (Grant No. 11971021).","BARTELS S., PROHL A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal, 44, pp. 1405-1419, (2006); BEAUREPAIRE E., MERLE J.-C., DAUNOIS A., BIGOT J.-Y., Ultrafast spin dynamics in ferromagnetic nickel, Phys. Rev. Lett, 76, pp. 4250-4253, (1996); BHATTACHARJEE S., NORDSTROM L., FRANSSON J., Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett, 108, (2012); BRATAAS A., KENT A. D., OHNO H., Current-induced torques in magnetic materials, Nat. Mater, 11, pp. 372-381, (2012); Hypre: scalable linear solvers and multigrid methods, (1952); CHEN J., WANG C., XIE C., Convergence analysis of a second-order semi-implicit projection method for Landau-Lifshitz equation, Appl. Numer. Math, 168, pp. 55-74, (2021); CIMRAK I., Error estimates for a semi-implicit numerical scheme solving the Landau-Lifshitz equation with an exchange field, IMA J. Numer. Anal, 25, pp. 611-634, (2005); CIMRAK I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng, 15, pp. 277-309, (2008); CIORNEI M.-C., RUBI J. M., WEGROWE J.-E., Magnetization dynamics in the inertial regime: Nutation predicted at short time scales, Phys. Rev. B, 83, (2011); GILBERT T., A Lagrangian formulation of gyromagnetic equation of the magnetization field, Phys. Rev, 100, pp. 1243-1255, (1955); KAMMERER M., WEIGAND M., CURCIC M., NOSKE M., SPROLL M., VANSTEENKISTE A., WAEYENBERGE B. V., STOLL H., WOLTERSDORF G., BACK C. H., SCHUETZ G., Magnetic vortex core reversal by excitation of spin waves, Nat. Commun, 2, pp. 1-6, (2011); KIM S. K., NAKATA K., LOSS D., TSERKOVNYAK Y., Tunable magnonic thermal hall effect in skyrmion crystal phases of ferrimagnets, Phys. Rev. Lett, 122, (2019); KRUZIK M., PROHL A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); LAN J., YU W., XIAO J., Geometric magnonics with chiral magnetic domain walls, Phys. Rev. B, 103, (2021); LANDAU L., LIFSHITZ E., On the theory of the dispersion of magetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); LI P., XIE C., DU R., CHEN J., WANG X.-P., Two improved Gauss-Seidel projection methods for Landau-Lifshitz-Gilbert equation, J. Comput. Phys, 401, (2020); LI Y., BARRA A.-L., AUFFRET S., EBELS U., BAILEY W. E., Inertial terms to magnetization dynamics in ferromagnetic thin films, Phys. Rev. B, 92, (2015); MANFRED F., DANIEL S., CHRISTIAN I., Generalized Gilbert equation including inertial damping: Derivation from an extended breathing Fermi surface model, Phys. Rev. B, 84, (2011); National institute of standards and technology, (2000); NEERAJ K., Et al., Inertial spin dynamics in ferromagnets, Nat. Phys, 17, pp. 245-250, (2021); RUGGERI M., Numerical analysis of the Landau-Lifshitz-Gilbert equation with inertial effects, ESAIM: Math. Model. Numer, 56, pp. 1199-1222, (2022); SAAD Y., MARTIN H. S., GMRES: A generalized minimal residual algorithm for solving nonsymmetric linear systems, SIAM J. Sci. Comput, 7, pp. 856-869, (1986); SUN Y., CHEN J., DU R., WANG C., Advantages of a semi-implicit scheme over a fully implicit scheme for Landau-Lifshitz-Gilbert equation, (2021); WANG X.-P., GARCIA-CERVERA C. J., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, pp. 357-372, (2001); XIE C., GARCIA-CERVERA C. J., WANG C., ZHOU Z., CHEN J., Second-order semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys, 404, (2020); ZUTIC I., FABIAN J., DAS SARMA S., Spintronics: Fundamentals and applications, Rev. Mod. Phys, 76, pp. 323-410, (2004)","R. Du; School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; email: durui@suda.edu.cn","","Global Science Press","","","","","","10048979","","","","English","Numer. Math.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85151848635" +"Hane Y.; Mitsuya K.; Nakamura K.","Hane, Yoshiki (36632081800); Mitsuya, Kazuhide (57803776300); Nakamura, Kenji (55516112700)","36632081800; 57803776300; 55516112700","Reluctance Network Model of Switched Reluctance Motor Considering Magnetic Hysteresis Behavior","2021","Digests of the Intermag Conference","2021-April","","","","","","1","10.1109/INTERMAG42984.2021.9579956","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125945229&doi=10.1109%2fINTERMAG42984.2021.9579956&partnerID=40&md5=b3fbc1201726baf84f39d9bfaa788d28","Tohoku University, Graduate School of Engineering, Sendai, 980-8579, Japan","Hane Y., Tohoku University, Graduate School of Engineering, Sendai, 980-8579, Japan; Mitsuya K., Tohoku University, Graduate School of Engineering, Sendai, 980-8579, Japan; Nakamura K., Tohoku University, Graduate School of Engineering, Sendai, 980-8579, Japan","Quantitative analysis of the iron loss taking the magnetic hysteresis behavior into account is essential to development of highefficiency electric machines. In previous papers, a novel reluctance network analysis (RNA) model incorporating a play model, which is one of the phenomenological models of the magnetic hysteresis, was proposed. It was clear that the proposed method can calculate the iron loss including the magnetic hysteresis with high accuracy by using the simple model. However, this method has been applied to devices in which voltage and current waveforms are almost sinusoidal. Therefore, in this paper, the versatility of the proposed method for a switched reluctance (SR) motor, whose flux waveform is distorted and dc-biased due to the square-wave voltage excitation, is experimentally demonstrated. © 2021 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Play model; Reluctance network analysis (RNA); Switched reluctance (SR) motor","Electric losses; Magnetism; Reluctance motors; RNA; Higher efficiency; Hysteresis behavior; Iron loss; Landau-Lifshitz-Gilbert equations; Network models; Play model; Reluctance network analyse; Reluctance network analysis; Reluctance network analysis models; Switched Reluctance Motor - SRM; Iron","","","","","Japan Society for the Promotion of Science, KAKEN, (JP19J20572)","ACKNOWLEDGEMENT This work was supported by Grant-in-Aid for JSPS Fellows (JP19J20572).","Steinmetz C.P., On the law of hysteresis, Proc. IEEE, 72, 2, pp. 197-221, (1984); Jiles D.C., Atherton D.L., Theory of ferromagnetic hysteresis, J. Magn. Magn. Mater., 61, 1-2, pp. 48-60, (1986); Friedman G., New formulation of the stoner-wolfarth hysteresis model and the identification problems, J. Appl. Phys., 67, 9, pp. 5361-5563, (1990); Park G.S., Hahn S.Y., Lee K.S., Jung H.K., Implementation of hysteresis characteristics using the preisach model with M-B variables, IEEE Trans. Magn., 29, 2, pp. 1542-1545, (1993); Fukuda H., Nakatani Y., Recording density limitation explored by head/media co-optimization using genetic algorithm and GPU accelerated LLG, IEEE Trans. Magn., 48, 11, pp. 3895-3898, (2012); Oshima H., Uehara Y., Shimizu K., Inagaki K., Furuya A., Fujisaki J., Suzuki M., Kawano K., Mifune T., Matsuo T., Watanabe K., Igarashi H., Experimental and simulation modeling studies of magnetic properties of Ni-Zn ferrite cores under DC bias, J. Jpn. Soc. Powder Metallurgy, 61, pp. S238-S241, (2014); Tanaka H., Nakamura K., Ichinokura O., Calculation of iron loss in soft ferromagnetic materials using magnetic circuit model taking magnetic hysteresis into consideration, Journal of the Magnetics Society of Japan, 39, 2, pp. 65-70, (2015); Tanaka H., Nakamura K., Ichinokura O., Accuracy improvement of magnetic hysteresis calculated by LLG equation, Journal of Physics: Conf. Series, 903, (2017); Bobbio S., Miano G., Serpico C., Visone C., Models of magnetic hysteresis based on play and stop hysteresis, IEEE Trans. Magn., 33, 6, pp. 4417-4426, (1997); Tanaka H., Nakamura K., Ichinokura O., Magnetic circuit model combined with play model obtained from landau-lifshitz-gilbert equation, Journal of Physics: Conf. Series, 903, (2017); Nakamura K., Ichinokura O., Reluctance network based dynamic analysis in power magnetics, IEEJ Trans. FM, 128, 8, pp. 506-510, (2008); Nakamura K., Kimura K., Ichinokura O., Electromagnetic and motion coupled analysis for switched reluctance motor based on reluctance network analysis, Journal of Magnetism and Magnetic Materials, 290-291, pp. 1309-1312, (2005); Fukuoka M., Nakamura K., Ichinokura O., Dynamic analysis of planetary-type magnetic gear based on reluctance network analysis, IEEE Trans. Magnetics, 47, 10, pp. 2414-2417, (2011); Nakamura K., Honma K., Ohinata T., Arimatsu K., Shirasaki T., Ichinokura O., Basic characteristics of lap-winding type three-phase laminated-core variable inductor, Journal of the Magnetics Society of Japan, 38, 4, pp. 174-177, (2014); Hane Y., Nakamura K., Reluctance network model of permanent magnet synchronous motor considering magnetic hysteresis behavior, Proceedings of 2018 IEEE International Magnetics Conference (INTERMAG 2018), (2018); Hane Y., Nakamura K., Ohinata T., Arimatsu K., Reluctance network model of three-phase-laminated-core variable inductor considering magnetic hysteresis behavior, IEEE Trans. Magn., 55, 7, (2019); Hane Y., Nakamura K., Dynamic hysteresis modeling for magnetic circuit analysis by incorporating play model and cauer's equivalent circuit theory, IEEE Trans. Magn., 56, 8, (2020)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Magnetics Society","2021 IEEE International Magnetic Conference, INTERMAG 2021","26 April 2021 through 30 April 2021","Virtual, Online","177034","00746843","978-073813099-6","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-85125945229" +"Rüßmann P.; Ribas Sobreviela J.; Sallermann M.; Hoffmann M.; Rhiem F.; Blügel S.","Rüßmann, Philipp (57191038324); Ribas Sobreviela, Jordi (57480964700); Sallermann, Moritz (57209284311); Hoffmann, Markus (57199660443); Rhiem, Florian (57204775533); Blügel, Stefan (10640602400)","57191038324; 57480964700; 57209284311; 57199660443; 57204775533; 10640602400","The AiiDA-Spirit Plugin for Automated Spin-Dynamics Simulations and Multi-Scale Modeling Based on First-Principles Calculations","2022","Frontiers in Materials","9","","825043","","","","2","10.3389/fmats.2022.825043","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125965334&doi=10.3389%2ffmats.2022.825043&partnerID=40&md5=258c26df11a32b749d3226ae805ee411","Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany; RWTH Aachen University, Aachen, Germany; Science Institute and Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík, Iceland; Peter Grünberg Institut/Jülich Centre for Neutron Science—Technical Services and Administration (PGI/JCNS-TA, Forschungszentrum Jülich, Jülich, Germany","Rüßmann P., Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany; Ribas Sobreviela J., Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany, RWTH Aachen University, Aachen, Germany; Sallermann M., Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany, RWTH Aachen University, Aachen, Germany, Science Institute and Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík, Iceland; Hoffmann M., Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany, RWTH Aachen University, Aachen, Germany; Rhiem F., Peter Grünberg Institut/Jülich Centre for Neutron Science—Technical Services and Administration (PGI/JCNS-TA, Forschungszentrum Jülich, Jülich, Germany; Blügel S., Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany","Landau-Lifshitz-Gilbert (LLG) spin-dynamics calculations based on the extended Heisenberg Hamiltonian is an important tool in computational materials science involving magnetic materials. LLG simulations allow to bridge the gap from expensive quantum mechanical calculations with small unit cells to large supercells where the collective behavior of millions of spins can be studied. In this work we present the AiiDA-Spirit plugin that connects the spin-dynamics code Spirit to the AiiDA framework. AiiDA provides a Python interface that facilitates performing high-throughput calculations while automatically augmenting the calculations with metadata describing the data provenance between calculations in a directed acyclic graph. The AiiDA-Spirit interface thus provides an easy way for high-throughput spin-dynamics calculations. The interface to the AiiDA infrastructure furthermore has the advantage that input parameters for the extended Heisenberg model can be extracted from high-throughput first-principles calculations including a proper treatment of the data provenance that ensures reproducibility of the calculation results in accordance to the FAIR principles. We describe the layout of the AiiDA-Spirit plugin and demonstrate its capabilities using selected examples for LLG spin-dynamics and Monte Carlo calculations. Furthermore, the integration with first-principles calculations through AiiDA is demonstrated at the example of γ–Fe, where the complex spin-spiral ground state is investigated. Copyright © 2022 Rüßmann, Ribas Sobreviela, Sallermann, Hoffmann, Rhiem and Blügel.","antiskyrmion; gamma-Fe; high-throughput computation; Landau-Lifshitz-Gilbert equation; Monte-Carlo simulation; skyrmion; spin-dynamics simulation; spin-spiral state","Directed graphs; Ground state; Hamiltonians; Intelligent systems; Iron compounds; Magnetic materials; Monte Carlo methods; Quantum theory; Spin dynamics; Antiskyrmion; Dynamics simulation; Gamma-fe; High-throughput; High-throughput computation; Landau-Lifshitz-Gilbert equations; Plug-ins; Skyrmions; Spin-dynamic simulation; Spin-spiral state; Calculations","","","","","JARA Vergabegremium, (jara0191); Joint Lab Virtual Materials Design; Deutsche Forschungsgemeinschaft, DFG, (ML4Q) EXC 2004/1—390534769)","We acknowledge support by the Joint Lab Virtual Materials Design (JL-VMD) and thank for computing time granted by the JARA Vergabegremium (project number jara0191) and provided on the JARA Partition part of the supercomputer CLAIX at RWTH Aachen University. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy—Cluster of Excellence Matter and Light for Quantum Computing (ML4Q) EXC 2004/1—390534769. ","Back C., Cros V., Ebert H., Everschor-Sitte K., Fert A., Garst M., Et al., The 2020 Skyrmionics Roadmap, J. Phys. D: Appl. Phys, 53, (2020); Bessarab P.F., Uzdin V.M., Jonsson H., Harmonic Transition-State Theory of thermal Spin Transitions, Phys. Rev. B, 85, (2012); Bessarab P.F., Uzdin V.M., Jonsson H., Method for Finding Mechanism and Activation Energy of Magnetic Transitions, Applied to Skyrmion and Antivortex Annihilation, Comput. Phys. Commun, 196, pp. 335-347, (2015); Binder K., Heermann D.W., Monte Carlo Simulation in Statistical Physics, (1997); Bogolubsky I.L., Three-dimensional Topological Solitons in the Lattice Model of a Magnet with Competing Interactions, Phys. Lett. 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Phys, 11, pp. 953-958, (2015); Heinze S., Von Bergmann K., Menzel M., Brede J., Kubetzka A., Wiesendanger R., Et al., Spontaneous Atomic-Scale Magnetic Skyrmion Lattice in Two Dimensions, Nat. Phys, 7, pp. 713-718, (2011); Himanen L., Geurts A., Foster A.S., Rinke P., Data‐Driven Materials Science: Status, Challenges, and Perspectives, Adv. Sci, 6, (2019); Hoffmann M., Blugel S., Systematic Derivation of Realistic Spin Models for Beyond-Heisenberg Solids, Phys. Rev. B, 101, (2020); Hoffmann M., Zimmermann B., Muller G.P., Schurhoff D., Kiselev N.S., Melcher C., Et al., Antiskyrmions Stabilized at Interfaces by Anisotropic Dzyaloshinskii-Moriya Interactions, Nat. Commun, 8, pp. 308-309, (2017); Hoffmann M., Muller G.P., Melcher C., Blugel S., Skyrmion-antiskyrmion Racetrack Memory in Rank-One Dmi Materials, Front. Phys, 9, (2021); Huber S.P., Zoupanos S., Uhrin M., Talirz L., Kahle L., Hauselmann R., Et al., AiiDA 1.0, a Scalable Computational Infrastructure for Automated Reproducible Workflows and Data Provenance, Sci. Data, 7, (2020); Kent N., Reynolds N., Raftrey D., Campbell I.T.G., Virasawmy S., Dhuey S., Et al., Creation and Observation of Hopfions in Magnetic Multilayer Systems, Nat. Commun, 12, pp. 1562-1567, (2021); Knopfle K., Sandratskii L.M., Kubler J., Spin Spiral Ground State of γ-Iron, Phys. Rev. B, 62, pp. 5564-5569, (2000); Kronlein A., Schmitt M., Hoffmann M., Kemmer J., Seubert N., Vogt M., Et al., Magnetic Ground State Stabilized by Three-Site Interactions: Fe/Rh(111), Phys. Rev. Lett, 120, (2018); Landau L., Lifshitz E., On the Theory of the Dispersion of Magnetic Permeability in Ferromagnetic Bodies, Phys. Z. Sowjet, 851, (1935); Lebert B.W., Gorni T., Casula M., Klotz S., Baudelet F., Ablett J.M., Et al., Epsilon Iron as a Spin-Smectic State, Proc. Natl. Acad. Sci. 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Lett, 77, pp. 3865-3868, (1996); Pizzi G., Cepellotti A., Sabatini R., Marzari N., Kozinsky B., AiiDA: Automated Interactive Infrastructure and Database for Computational Science, Comput. Mater. Sci, 111, pp. 218-230, (2016); Russmann P., Bertoldo F., Broder J., Wasmer J., Mozumder R., Chico J., Et al., JuDFTteam/aiida-kkr: AiiDA Plugin for the JuKKR Codes, (2021); Russmann P., Bertoldo F., Blugel S., The AiiDA-KKR Plugin and its Application to High-Throughput Impurity Embedding into a Topological Insulator, Npj Comput. Mater, 7, (2021); Russmann P., Ribas Sobreviela J., Sallermann M., Hoffmann M., Rhiem F., Blugel S., The AiiDA-Spirit Plugin for Automated Spin-Dynamics Simulations and Multi-Scale Modelling Based on First-Principles Calculations, Mater. Cloud Archive, (2021); Sjostedt E., Nordstrom L., Noncollinear Full-Potential Studies of γ−Fe, Phys. Rev. B, 66, (2002); Skubic B., Hellsvik J., Nordstrom L., Eriksson O., A Method for Atomistic Spin Dynamics Simulations: Implementation and Examples, J. Phys. Condens. Matter, 20, (2008); Stefanou N., Akai H., Zeller R., An Efficient Numerical Method to Calculate Shape Truncation Functions for Wigner-Seitz Atomic Polyhedra, Comput. Phys. Commun, 60, pp. 231-238, (1990); Stefanou N., Zeller R., Calculation of Shape-Truncation Functions for Voronoi Polyhedra, J. Phys. Condens. Matter, 3, pp. 7599-7606, (1991); Sutcliffe P., Hopfions in Chiral Magnets, J. Phys. A: Math. Theor, 51, (2018); Szilva A., Costa M., Bergman A., Szunyogh L., Nordstrom L., Eriksson O., Interatomic Exchange Interactions for Finite-Temperature Magnetism and Nonequilibrium Spin Dynamics, Phys. Rev. Lett, 111, (2013); Talirz L., Kumbhar S., Passaro E., Yakutovich A.V., Granata V., Gargiulo F., Et al., Materials Cloud, a Platform for Open Computational Science, Sci. Data, 7, (2020); The Aiida-Spirit Plugin, (2021); The AiiDA team, AiiDA Plugin Registry, (2021); The JuKKR developers, The Jülich KKR Codes, (2021); Tsunoda Y., Nishioka Y., Nicklow R.M., Spin Fluctuations in Small γ-Fe Precipitates, J. Magnetism Magn. Mater, 128, pp. 133-137, (1993); Tsunoda Y., Spin-density Wave in Cubic γ-Fe and γFe100-xCox precipitates in Cu, J. Phys. Condens. Matter, 1, pp. 10427-10438, (1989); Uhrin M., Huber S.P., Yu J., Marzari N., Pizzi G., Workflows in AiiDA: Engineering a High-Throughput, Event-Based Engine for Robust and Modular Computational Workflows, Comput. Mater. Sci, 187, (2021); Vfrendering, A Vector Field Rendering Library, (2021); Weissenhofer M., Rozsa L., Nowak U., Skyrmion Dynamics at Finite Temperatures: Beyond Thiele's Equation, Phys. Rev. Lett, 127, (2021); Wilkinson M.D., Dumontier M., Aalbersberg I.J., Appleton G., Axton M., Baak A., Et al., The FAIR Guiding Principles for Scientific Data Management and Stewardship, Sci. Data, 3, (2016); Xu Q., Bergman A., Delin A., Chico J., The UppASD-AiiDA Plugin, (2021); Yu X.Z., Onose Y., Kanazawa N., Park J.H., Han J.H., Matsui Y., Et al., Real-space Observation of a Two-Dimensional Skyrmion crystal, Nature, 465, pp. 901-904, (2010)","P. Rüßmann; Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Jülich, Jülich, Germany; email: p.ruessmann@fz-juelich.de","","Frontiers Media S.A.","","","","","","22968016","","","","English","Front. Mater.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85125965334" +"Kurniawan C.; Djuhana D.; Soegijono B.; Kim D.-H.","Kurniawan, Candra (55600299500); Djuhana, Dede (26027849100); Soegijono, Bambang (15754907100); Kim, Dong-Hyun (57198636797)","55600299500; 26027849100; 15754907100; 57198636797","Micromagnetic investigation of the sub-nanosecond magnetic pulse driven domain wall motion in CoFeB nanowire","2021","Current Applied Physics","27","","","98","102","4","2","10.1016/j.cap.2021.04.017","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85105697785&doi=10.1016%2fj.cap.2021.04.017&partnerID=40&md5=065ac19b0e929737806fe0b66e1bd4fd","Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus Baru UI Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Serpong, 15314, Indonesia; Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea","Kurniawan C., Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus Baru UI Depok, 16424, Indonesia, Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Serpong, 15314, Indonesia; Djuhana D., Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus Baru UI Depok, 16424, Indonesia; Soegijono B., Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus Baru UI Depok, 16424, Indonesia; Kim D.-H., Department of Physics, Chungbuk National University, Cheongju, 28644, South Korea","We report our micromagnetic simulations based on Landau-Lifshitz-Gilbert (LLG) equation for CoFeB nanowire which was exposed by sub-nanosecond magnetic pulse with varied pulse width between 100 and 1000 ps. It is found that the Walker Breakdown field (HWB) shifted as the field pulse duration decreased and reached at the highest value in case of 100 ps pulse width, then decreased steeply with respect to the pulse width up to 400 ps. HWB values are not significantly dependent for pulses longer than 500 ps. It is observed that, below the HWB, the exchange energy is larger than the demagnetization energy in the wider nanowire. By energy density analysis, it is understood that the increase of HWB values in the cases of narrower pulse width was to compensate the energy needed to move the DW. © 2021 Korean Physical Society","CoFeB nanowire; Domain wall; Magnetic pulse; Micromagnetics; Walker breakdown","Cobalt compounds; Domain walls; Iron compounds; CoFeB nanowire; Domain wall motion; Landau-Lifshitz-Gilbert equations; Magnetic pulse; Micromagnetic simulations; Micromagnetics; Pulsewidths; Pulswidths; Sub nanoseconds; Walker breakdown; Nanowires","","","","","","","Szambolics H., Toussaint J.-C., Marty A., Miron I.M., Buda-Prejbeanu L.D., Domain wall motion in ferromagnetic systems with perpendicular magnetization, J. Magn. Magn Mater., 321, pp. 1912-1918, (2009); Ono T., Propagation of a magnetic domain wall in a submicrometer magnetic wire, Science, 284, pp. 468-470, (1999); Beach G.S.D., Nistor C., Knutson C., Tsoi M., Erskine J.L., Dynamics of field-driven domain-wall propagation in ferromagnetic nanowires, Nat. Mater., 4, pp. 741-744, (2005); Schryer N.L., Walker L.R., The motion of 180° domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, pp. 5406-5421, (1974); Kohno H., Tatara G., Theoretical aspects of current-driven magnetization dynamics, Nanomagnetism Spintron., pp. 213-259, (2014); Thomas L., Parkin S., Current induced domain-wall motion in magnetic nanowires, Handb. Magn. Adv. Magn. Mater., (2007); Djuhana D., Piao H.-G., Yu S.-C., Oh S.K., Kim D.-H., Magnetic domain wall collision around the Walker breakdown in ferromagnetic nanowires, J. Appl. Phys., 106, (2009); Lee J.-Y., Lee K.-S., Choi S., Guslienko K.Y., Kim S.-K., Dynamic transformations of the internal structure of a moving domain wall in magnetic nanostripes, Phys. Rev. B, 76, (2007); Mougin A., Cormier M., Adam J.P., Metaxas P.J., Ferre J., Domain wall mobility, stability and Walker breakdown in magnetic nanowires, Europhys. Lett. EPL., 78, (2007); Wieser R., Nowak U., Usadel K.D., Domain wall mobility in nanowires: transverse versus vortex walls, Phys. Rev. B, 69, (2004); Moon K.-W., Kim D.-H., Kim C., Kim D.-Y., Choe S.-B., Hwang C., Domain wall motion driven by an oscillating magnetic field, J. Phys. Appl. Phys., 50, (2017); Sun Z.Z., Schliemann J., Fast domain wall propagation under an optimal field pulse in magnetic nanowires, Phys. Rev. Lett., 104, (2010); Ciureanu M., Beron F., Clime L., Ciureanu P., Yelon A., Ovari T.A., Cochrane R.W., Normandin F., Veres T., Magnetic properties of electrodeposited CoFeB thin films and nanowire arrays, Electrochim. Acta, 50, pp. 4487-4497, (2005); Zhang Y., Zhao W.S., Ravelosona D., Klein J.-O., Kim J.V., Chappert C., Perpendicular-magnetic-anisotropy CoFeB racetrack memory, J. Appl. Phys., 111, (2012); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 1.0, (1999); Gilbert T.L., Classics in magnetics A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Kronmuller H., General micromagnetic theory, Handb. Magn. Adv. Magn. Mater, 2, pp. 1-39, (2007); Chaves-O'Flynn G.D., Wolf G., Pinna D., Kent A.D., Micromagnetic study of spin transfer switching with a spin polarization tilted out of the free layer plane, J. Appl. Phys., 117, (2015); Jamali M., Lee K.-J., Yang H., Effect of nonadiabatic spin transfer torque on domain wall resonance frequency and mass, Appl. Phys. Lett., 98, (2011); Huang S.-H., Lai C.-H., Domain-wall depinning by controlling its configuration at notch, Appl. Phys. Lett., 95, (2009); Lee J.-Y., Lee K.-S., Choi S., Guslienko K.Y., Kim S.-K., Dynamic transformations of the internal structure of a moving domain wall in magnetic nanostripes, Phys. Rev. B, 76, (2007); Bran C., Fernandez-Roldan J.A., Palmero E.M., Berganza E., Guzman J., del Real R.P., Asenjo A., Fraile Rodriguez A., Foerster M., Aballe L., Chubykalo-Fesenko O., Vazquez M., Direct observation of transverse and vortex metastable magnetic domains in cylindrical nanowires, Phys. Rev. B, 96, (2017); Donahue M.J., Micromagnetic investigation of periodic cross-tie/vortex wall geometry, Adv. Condens. Matter Phys., 2012, pp. 1-8, (2012)","D. Djuhana; Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Kampus Baru UI Depok, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","","Elsevier B.V.","","","","","","15671739","","","","English","Curr. Appl. Phys.","Article","Final","","Scopus","2-s2.0-85105697785" +"Freitas L.A.L.; Neto O.P.V.; Rahmeier J.G.N.; Melo L.G.C.","Freitas, Lucas A. Lascasas (57194146859); Neto, Omar P. Vilela (15623824700); Rahmeier, João G. Nizer (56180250600); Melo, Luiz G.C. (57143838200)","57194146859; 15623824700; 56180250600; 57143838200","NMLSim 2.0: A robust CAD and simulation tool for in-plane Nanomagnetic Logic based on the LLG equation","2019","Proceedings - 32nd Symposium on Integrated Circuits and Systems Design, SBCCI 2019","","","a23","","","","13","10.1145/3338852.3339856","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85073471491&doi=10.1145%2f3338852.3339856&partnerID=40&md5=0bb47dca8798d49f4d4fea6434e02746","Federal University of Minas Gerais, Department of Computer Science, Belo Horizonte, MG, Brazil; Carleton University, Department of Electronics, Ottawa, ON, Canada; Atelier 7hz Acoustics and Vibration Engineering, Montreal, QC, Canada","Freitas L.A.L., Federal University of Minas Gerais, Department of Computer Science, Belo Horizonte, MG, Brazil; Neto O.P.V., Federal University of Minas Gerais, Department of Computer Science, Belo Horizonte, MG, Brazil; Rahmeier J.G.N., Carleton University, Department of Electronics, Ottawa, ON, Canada; Melo L.G.C., Atelier 7hz Acoustics and Vibration Engineering, Montreal, QC, Canada","Nanomagnetic Logic (NML) is a new technology based on the magnetization of nanometric magnets. Logic operations are performed via dipolar coupling through ferromagnetic and antiferromagnetic interactions. The low energy dissipation and the possibility of higher integration density in circuits are significant advantages over CMOS technology. Even so, there is a great need for simulation and CAD tools for the proper study of large NML circuits. This paper presents a high-efficiency tool that uses the Landau-Lifshitz-Gilbert equation to evolve the magnetization of the particles over time in a monodomain approach. The new version of NMLSim comes with flexibility in its code, allowing expansion of the tool with ease and consistency. The results of simulated structures show the reliability of the simulator when compared with the current state of the art Object-Oriented Micromagnetic Framework (OOMMF). It also presents an improvement of up to 716 times in execution time and up to 41 times in memory usage. © 2019 Association for Computing Machinery.","Beyond CMOS; CAD tool; LLG; Nanomagnetic Logic","CMOS integrated circuits; Computer aided design; Energy dissipation; Low power electronics; Magnetization; Nanomagnetics; Systems analysis; Beyond CMOS; CAD tool; Ferromagnetic and anti-ferromagnetic; Landau-Lifshitz-Gilbert equations; Low energy dissipations; Nanomagnetic logic; Nanomagnetic logic (NML); Simulated structure; Computer circuits","","","","","","","Mitchell Waldrop M., The chips are down for moore's law, Nature, 530, 7589, pp. 144-147, (2016); Cavin R.K., Lugli P., Zhirnov V.V., Science and engineering beyond moore's law, Proceedings of the IEEE, 100(Special Centennial Issue), pp. 1720-1749, (2012); Melo C.L.G., Soares S.B.T.R., Neto Vilela O.P., Analysis of the magnetostatic energy of chains of single-domain nanomagnets for logic gates, IEEE Transactions on Magnetics, 53, 9, pp. 1-10, (2017); Niemier M.T., Bernstein G.H., Csaba G., Dingler A., Hu X.S., Kurtz S., Liu S., Nahas J., Porod W., Siddiq M., Et al., Nanomagnet logic: Progress toward systemlevel integration, Journal of Physics: Condensed Matter, 23, 49, (2011); Imre A., Csaba G., Ji L., Orlov A., Bernstein G.H., Porod W., Majority logic gate for magnetic quantum-dot cellular automata, Science, 311, 5758, pp. 205-208, (2006); Varga E., Orlov A., Niemier M.T., Sharon Hu X., Bernstein G.H., Porod W., Experimental demonstration of fanout for nanomagnetic logic, IEEE Transactions on Nanotechnology, 9, 6, pp. 668-670, (2010); Varga E., Csaba G., Bernstein G.H., Porod W., Implementation of a nanomagnetic full adder circuit, 2011 11th IEEE International Conference on Nanotechnology, pp. 1244-1247, (2011); Hubert A., Schafer R., Magnetic Domains: The Analysis of Magnetic Microstructures, (2008); Graziano M., Chiolerio A., Zamboni M., A technology aware magnetic qca ncl-hdl architecture, 2009 9th IEEE Conference on Nanotechnology (IEEE-NANO), pp. 763-766, (2009); Graziano M., Vacca M., Chiolerio A., Zamboni M., An ncl-hdl snake-clock-based magnetic qca architecture, IEEE Transactions on Nanotechnology, 10, 5, pp. 1141-1149, (2011); Soares S.B.T.R., Rahmeier Nizer J.G., Lima De V.C., Lascasas L., Melo Costa L.G., Neto Vilela O.P., NMLSim: A Nanomagnetic Logic (NML) circuit designer and simulation tool, Journal of Computational Electronics, 17, 3, pp. 1370-1381, (2018); Csaba G., Porod W., Behavior of nanomagnet logic in the presence of thermal noise, 2010 14th InternationalWorkshop on Computational Electronics, pp. 1-4, (2010); Vansteenkiste A., Leliaert J., Dvornik M., Garcia-Sanchez F., Van Waeyenberge B., The Design and Verification of mumax3, Aip Advances, 4, (2014); Scheinfein M.R., Llg Micromagnetics Simulator, 18, (1997); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 1.2 Beta 0, (2016); Riente F., Turvani G., Vacca M., Roch M.R., Zamboni M., Graziano M., Topolinano: A cad tool for nano magnetic logic, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 36, 7, pp. 1061-1074, (2017); Riente F., Garlando U., Turvani G., Vacca M., Ruo Roch M., Graziano M., Magcad: Tool for the design of 3-d magnetic circuits, IEEE Journal on Exploratory Solid-State Computational Devices and Circuits, 3, pp. 65-73, (2017); Soares T.R.B.S., Silva I.F., Melo L.G.C., Neto Vilela O.P., A new methodology for design and simulation of nml circuits, 2016 IEEE 7th Latin American Symposium on Circuits & Systems (LASCAS), pp. 259-262, (2016); Yin L.F., Wei D.H., Lei N., Zhou L.H., Tian C.S., Dong G.S., Jin X.F., Guo L.P., Jia Q.J., Wu R.Q., Magnetocrystalline anisotropy in permalloy revisited, Physical Review Letters, 97, 6, pp. 1-4, (2006); Moskowitz R., Della Torre E., Theoretical aspects of demagnetization tensors, IEEE Transactions on Magnetics, 2, 4, pp. 739-744, (1966); Stoer J., Bulirsch R., Introduction to Numerical Analysis, (2002); Cimrak I., A survey on the numerics and computations for the landau-lifshitz equation of micromagnetism, Archives of Computational Methods in Engineering, 15, 3, pp. 277-309, (2008); Kurtz S., Varga E., Siddiq M.J., Niemier M., Porod W., Hu X.S., Bernstein G.H., Nonmajority magnetic logic gates: A review of experiments and future prospects for 'shape- based' logic Non-majority magnetic logic gates: A review of experiments and future prospects for 'shape-based' logic, J. Phys.: Condens. Matter, 23, pp. 53202-53213, (2011)","","","Association for Computing Machinery, Inc","ACM Sigda; IEEE Circuits and Systems Society; IEEE Council on Electronic Design Automation; International Federation for Information Processing (IFIP)","32nd Symposium on Integrated Circuits and Systems Design, SBCCI 2019","26 August 2019 through 30 August 2019","Sao Paulo","152182","","978-145036844-5","","","English","Proc. - Symp. Integr. Circuits Syst. Des., SBCCI","Conference paper","Final","","Scopus","2-s2.0-85073471491" +"Perach B.; Kvatinsky S.","Perach, Ben (57201677450); Kvatinsky, Shahar (36866322000)","57201677450; 36866322000","An Asynchronous and Low-Power True Random Number Generator Using STT-MTJ","2019","IEEE Transactions on Very Large Scale Integration (VLSI) Systems","27","11","8790991","2473","2484","11","21","10.1109/TVLSI.2019.2927816","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85077500116&doi=10.1109%2fTVLSI.2019.2927816&partnerID=40&md5=bf187403c39bb6dfa4026bcb1962b54f","Andrew and Erna Finci Viterbi Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel","Perach B., Andrew and Erna Finci Viterbi Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel; Kvatinsky S., Andrew and Erna Finci Viterbi Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel","The emerging spin-transfer torque magnetic tunnel junction (STT-MTJ) technology exhibits interesting stochastic behavior combined with small area and low operation energy. It is, therefore, a promising technology for security applications, specifically the generation of random numbers. In this paper, STT-MTJ is used to construct an asynchronous true random number generator (TRNG) with low power and a high entropy rate. The asynchronous design enables the decoupling of the random number generation from the system clock, allowing it to be embedded in low-power devices. The proposed TRNG is evaluated by a numerical simulation, using the Landau-Lifshitz-Gilbert (LLG) equation as the model of the STT-MTJ devices. Design considerations, attack analysis, and process variation are discussed and evaluated. We show that our design is robust to process variation, thus achieving an entropy generating rate between 99.7 and 127.8 Mb/s with 6-7.7 pJ per bit for 90% of the instances. © 2019 IEEE.","Hardware security; magnetic tunnel junction (MTJ); memristors; random number generation; true random number generator (TRNG)","Entropy; Hardware security; Magnetic devices; Memristors; Number theory; Stochastic systems; Tunnel junctions; Asynchronous design; Design considerations; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Security application; Spin transfer torque; Stochastic behavior; True randoms; Random number generation","","","","","Israel Cyber Bureau; Technion Hiroshi Fujiwara Cyber Security Research Center; Horizon 2020 Framework Programme, H2020; European Research Council, ERC; Horizon 2020, (757259)","Manuscript received January 10, 2019; revised April 16, 2019 and June 8, 2019; accepted June 24, 2019. Date of publication August 7, 2019; date of current version October 23, 2019. This work was supported in part by the European Research Council (ERC) through the European Union’s Horizon 2020 Research and Innovation Programme under Grant 757259, in part by the Technion Hiroshi Fujiwara Cyber Security Research Center, and in part by the Israel Cyber Bureau. (Corresponding author: Ben Perach.) The authors are with the Andrew and Erna Finci Viterbi Faculty of Electrical Engineering, Technion–Israel Institute of Technology, Haifa 3200003, Israel (e-mail: benperach@campus.technion.ac.il; shahar@ee.technion.ac.il).","Eastlake D., Schiller J., Crocker S., RFC4086: Randomness Requirements for Security, (2005); Menezes A.J., Van Oorschot P.C., Vanstone S.A., Handbook of Applied Cryptography, (1996); Goldberg I., Wagner D., Randomness and the Netscape Browser, (1996); Gutterman Z., Pinkas B., Reinman T., Open to Attack: Vulnerabilities of the Linux Random Number Generator, Black Hat, (2006); Kelsey J., Schneier B., Wagner D., Hall C., Cryptanalytic attacks on pseudorandom number generators, Proc. 5th Int. Workshop Fast Softw. 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(VLSI) Syst., 26, 8, pp. 1508-1517, (2018); Li J., Augustine C., Salahuddin S., Roy K., Modeling of failure probability and statistical design of spin-torque transfer magnetic random access memory (STT MRAM) array for yield enhancement, Proc. 45th Annu. Design Autom. Conf. (DAC), pp. 278-283, (2008); Goode D.A., Rowlands G., The demagnetizing energies of a uniformly magnetized cylinder with an elliptic cross-section, J. Magn. Magn. Mater., 267, 3, pp. 373-385, (2003); Dong Q., Et al., A 1 Mb 28 nm STT-MRAM with 2.8 ns read access time at 1.2 v VDD using single-cap offset-cancelled sense amplifier and in-situ self-write-termination, IEEE Int. Solid-State Circuits Conf. (ISSCC) Dig. Tech. Papers, pp. 480-482, (2018); Patel R., Guo X., Guo Q., Ipek E., Friedman E.G., Reducing switching latency and energy in STT-MRAM caches with field-assisted writing, IEEE Trans. Very Large Scale Integr. (VLSI) Syst., 24, 1, pp. 129-138, (2016); Yamada K., Anisotropic magnetic shielding effectiveness of magnetic shielded package, IEEE Trans. Magn., 53, 11, (2017); Wang W., Jiang Z., Magnetic shielding design for magnetoelectronic devices protection, IEEE Trans. Magn., 44, 11, pp. 4175-4178, (2008); Paperno E., Koide H., Sasada I., Charts for estimating the axial shielding factors for triple-shell open-ended cylindrical shields, IEEE Trans. Magn., 37, 4, pp. 2881-2883, (2001)","B. Perach; Andrew and Erna Finci Viterbi Faculty of Electrical Engineering, Technion-Israel Institute of Technology, Haifa, Israel; email: benperach@campus.technion.ac.il","","Institute of Electrical and Electronics Engineers Inc.","","","","","","10638210","","IEVSE","","English","IEEE Trans Very Large Scale Integr VLSI Syst","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85077500116" +"Ishida Y.; Kondo K.","Ishida, Yuichi (57210433494); Kondo, Kenji (35264005600)","57210433494; 35264005600","An effect of the Gilbert damping constant on the skyrmion Hall effect","2020","Journal of Magnetism and Magnetic Materials","493","","165687","","","","10","10.1016/j.jmmm.2019.165687","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85070675513&doi=10.1016%2fj.jmmm.2019.165687&partnerID=40&md5=6e5041ea8234bc7f48ac79f08ae1d9aa","Research Institute for Electronic Science, Hokkaido University, Kita-20, Nishi-10, Sapporo, Hokkaido, Japan","Ishida Y., Research Institute for Electronic Science, Hokkaido University, Kita-20, Nishi-10, Sapporo, Hokkaido, Japan; Kondo K., Research Institute for Electronic Science, Hokkaido University, Kita-20, Nishi-10, Sapporo, Hokkaido, Japan","We investigate the skyrmion Hall effect using the Landau-Lifshitz-Gilbert (LLG) equation and the Thiele equation, respectively. Then, we find that these methods give different values for the ratio of in-plane skyrmion velocity components when the Gilbert damping constant is relatively small. Since the Thiele equation is derived from the LLG equation by assuming that the skyrmion structure does not change and behaves like a rigid body, the above result suggests that this assumption does not hold when the Gilbert damping constant is relatively small. Therefore, we conclude that the Thiele equation can not describe the systems precisely under the relatively small Gilbert damping constant due to the distortion of the skyrmion structure and that it is mandatory to solve the LLG equation numerically in order to investigate the skyrmion Hall effect accurately. This result is very important since the Gilbert damping constants of metal materials are generally very small. © 2019 Elsevier B.V.","LLG equation; Micromagnetic simulation; Skyrmion Hall effect","Hall effect; Gilbert damping constant; Landau-Lifshitz-Gilbert equations; LLG equation; Metal materials; Micromagnetic simulations; Rigid body; Thiele equations; Velocity components; Damping","","","","","CSRN; Center for Spintronics Research Network; Grant-in-Aid for Scientific Research, (16K04872); JSPS, Center for Spintronics Research Network; Japan Society for the Promotion of Science, JSPS; Tohoku University","Funding text 1: This work is partially supported by a Grant-in-Aid for Scientific Research (Grant No. 16K04872) from JSPS, Center for Spintronics Research Network (CSRN) Tohoku University, and Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials.; Funding text 2: This work is partially supported by a Grant-in-Aid for Scientific Research (Grant No. 16K04872 ) from JSPS, Center for Spintronics Research Network (CSRN) Tohoku University, and Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials.","Nagaosa N., Tokura Y., Topological properties and dynamics of magnetic skyrmions, Nat. Nanotechnol., 8, (2013); Fert A., Cros V., Sampaio J., Skyrmions on the track, Nat. Nanotechnol., 8, (2013); Maekawa S., Adachi H., Uchida K.-I., Ieda J., Saitoh E., Spin current: experimental and theoretical aspects, J. Phys. Soc. Jpn., 82, 10, (2013); Hoffmann A., Spin hall effects in metals, IEEE Trans. Magn., 49, 10, pp. 5172-5193, (2013); Jiang W., Zhang X., Yu G., Zhang W., Wang X., Benjamin Jungfleisch M., Pearson J.E., Cheng X., Heinonen O., Wang K.L., Zhou Y., Hoffmann A., te Velthuis S.G.E., Direct observation of the skyrmion hall effect, Nat. Phys., 13, (2016); Bocdanov A., Hubert A., The properties of isolated magnetic vortices, Physica Status Solidi (b), 186, 2, pp. 527-543, (1994); Bogdanov A.N., Rossler U.K., Chiral symmetry breaking in magnetic thin films and multilayers, Phys. Rev. Lett., 87, (2001); Bogdanov A., Hubert A., The stability of vortex-like structures in uniaxial ferromagnets, J. Magn. Magn. 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B, 88, (2013); Tomasello R., Martinez E., Zivieri R., Torres L., Carpentieri M., Finocchio G., A strategy for the design of skyrmion racetrack memories, Scientific Rep., 4, (2014); Jiang W., Upadhyaya P., Zhang W., Yu G., Jungfleisch M.B., Fradin F.Y., Pearson J.E., Tserkovnyak Y., Wang K.L., Heinonen O., te Velthuis S.G.E., Hoffmann A., Blowing magnetic skyrmion bubbles, Science, 349, 6245, pp. 283-286, (2015); Emori S., Bauer U., Ahn S.-M., Martinez E., Beach G.S.D., Current-driven dynamics of chiral ferromagnetic domain walls, Nat. Mater., 12, (2013); Heinonen O., Jiang W., Somaily H., te Velthuis S.G.E., Hoffmann A., Generation of magnetic skyrmion bubbles by inhomogeneous spin hall currents, Phys. Rev. B, 93, (2016); Serpico C., Mayergoyz I.D., Bertotti G., Numerical technique for integration of the landau-lifshitz equation, J. Appl. Phys., 89, 11, pp. 6991-6993, (2001); Bottauscio O., Chiampi M., Manzin A., A finite element procedure for dynamic micromagnetic computations, IEEE Trans. Magn., 44, 11, pp. 3149-3152, (2008); Thiele A.A., Steady-state motion of magnetic domains, Phys. Rev. Lett., 30, pp. 230-233, (1973)","K. Kondo; Research Institute for Electronic Science, Hokkaido University, Sapporo, Kita-20, Nishi-10, Japan; email: kkondo@es.hokudai.ac.jp","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85070675513" +"Venugopal A.; Qu T.; Victora R.H.","Venugopal, Aneesh (57196415328); Qu, Tao (55236700100); Victora, R.H. (7003740581)","57196415328; 55236700100; 7003740581","Parallel Computations Based Micromagnetic Solver and Analysis Tools for Magnon-Microwave Interaction Studies","2021","IEEE Journal on Multiscale and Multiphysics Computational Techniques","6","","","239","248","9","3","10.1109/JMMCT.2022.3144432","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85123729993&doi=10.1109%2fJMMCT.2022.3144432&partnerID=40&md5=2fac09ce22c96d2bad58cae3f0bc8b37","Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States","Venugopal A., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Qu T., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Victora R.H., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States","Theinteraction of microwaves with magnetic materials gives rise to interesting and useful phenomena. The study of many such phenomena is, however, often complicated due to the nature of magnetic materials and/or the limitations in experimental techniques. In this work, we discuss the construction of a Landau Lifshitz Gilbert (LLG) equation-based micromagnetics solver using the parallel programming language- CUDA to study microwave-magnet interactions. The use of CUDA on Graphics Processing Units (GPUs) allows us to leverage the inherently parallel nature of the magnetic systems, thereby allowing large-scale (spatial and temporal) simulation-based studies that are otherwise unreasonable. In addition, computational techniques that allow a magnon-based interpretation of the physical processes are also introduced. Basic nonlinear magnonic phenomena, e.g., 3- and 4-magnon scattering and magnon growth dynamics, have been demonstrated. We show for the first time the direct excitation of magnons with nonzero wave-vectors in the context of parallel microwave pumping. © 2016 IEEE.","CUDA; FMR; four-magnon interaction; GPU; magnons; micromagnetics; microwave-magnet interaction; nonlinear processes; numerical computation; parallel computation; scattering; solver; spin waves; three-magnon interaction","Computation theory; Graphics processing unit; Magnetic anisotropy; Magnetization; Microwaves; Parallel programming; Program processors; Timing circuits; Computational modelling; CUDA; Four-magna interaction; Graphic processing unit; Graphics processing; Magnon interactions; Magnons; Micromagnetics; Microwave theory and techniques; Microwave-magnet interaction; Nonlinear process; Numerical computations; Parallel Computation; Perpendicular magnetic anisotropy; Processing units; Solv; Three-magna interaction; Magnets","","","","","Center for Micromagnetics and Information Technologies; Defense Advanced Research Projects Agency, DARPA, (W911NF-17-1-0100); Defense Advanced Research Projects Agency, DARPA","This work was supported in part by the U.S. Defense Advanced Research Projects Agency (DARPA) under Grant W911NF-17-1-0100 and in part by the Center for Micromagnetics and Information Technologies","Gurevich A.G., Ferrites at Microwave Frequencies, (1963); Gurevich A.G., Melkov G.A., Magnetization Oscillations AndWaves, (1996); Suhl H., The theory of ferromagnetic resonance at high signal powers, J. 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Lett., 117, (2020); Venugopal A., Victora R.H., Effective phase noise considerations in magnon based parametric excitations, Sci. Rep., 11, (2021); Venugopal A., Victora R.H., Dynamic threshold control and higherorder processes for magnetics based microwave devices, Proc. Int. Microw. Symp. (IMS MTT-S), pp. 358-361, (2021); Qu T., Et al., Nonlinear magnon scattering mechanism for microwave pumping in magnetic films, IEEE Access, 8, pp. 216960-216968, (2020); Shukla M., Koledintseva M.Y., Geiler M., Gillette S., Hunnewell M., Geiler A.L., Adaptive interference mitigation using frequency-selective limiters over GPS band for automotive applications, Proc. IEEE EMCSI, pp. 614-618, (2020); Geiler M., Gillette S., Shukla M., Kulik P., Geiler A.L., Microwave magnetics and considerations for systems design, IEEE J. Microw., 1, 1, pp. 438-446, (2021); Adam J.D., Winter F., Magnetostatic wave frequency selective limiters, IEEE Trans. Magn., 49, 3, pp. 956-962, (2013); Harris V.G., Modern microwave ferrites, IEEE Trans. Magn., 48, 3, pp. 1075-1104, (2012); Khitun A., Bao M., Wang K.L., Magnonic logic circuits, Phys. D: Appl. Phys., 43, (2010); Serga A.A., Chumak A.V., Hillebrands B., YIGmagnonics, J. Phys. D: Appl. Phys., 43, (2010); Vogt K., Et al., Realization of a spin-wave multiplexer, Nature Commun., 5, (2014); Chumak A., Serga A., Hillebrands B., Magnon transistor for allmagnon data processing, Nature Commun., 5, (2014); Goryachev M., Farr W.G., Creedon D.L., Fan Y., Kostylev M., Tobar M.E., High-cooperativity cavity QED with magnons at microwave frequencies, Phys. Rev. Appl., 2, (2014); Zhang X., Zou C.-L., Jiang L., Tang H.X., Strongly coupled magnons and cavity microwave photons, Phys. Rev. Lett., 113, (2014); Xu J., Zhong C., Han X., Jin D., Jiang L., Zhang X., Floquet cavity electromagnonics, Phys. Rev. Lett., 125, (2020); Tabuchi Y., Et al., Coherent coupling between a ferromagnetic magnon and a superconducting qubit, Science, pp. 405-408, (2015); Lax B., Button K.J., Microwave Ferrites and Ferrimagnets, (1962); Venugopal A., Ghoreyshi A., Victora R.H., High-density shingled heat-assisted recording using bit-patternedmedia subject to track misregistration, IEEE Trans. Magn., 53, 11, (2017); Taniguchi T., Theoretical condition for switching the magnetization in a perpendicularly magnetized ferromagnet via the spin hall effect, Phys. Rev. B, 100, (2019); Xue J., Victora R.H., Micromagnetic predictions for thermally assisted reversal over long time scales, Appl. Phys. Lett., 77, 21, (2000); Huang P.-W., Micromagnetic Study of Heat Assisted Magnetic Recording Using Renormalized Media Cells, (2014); Kirk D.B., Hwu W.-M.W., Programming Massively Parallel Processors: A Hands on Approach, 3rd Ed, (2017); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. 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C Solid State Phys., 19, (1986); L'vov V.S., Wave Turbulence under Parametric Excitation: Applications to Magnets, (1994); Wigen P.E., Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Zakharov V.E., L'vov V.S., Starobinets S.S., Stationary nonlinear theory of parametric excitation of waves, JETP, 32, 4, pp. 656-663, (1971); Tsukahara H., Iwano K., Mitsumata C., Ishikawa T., Ono K., Implementation of low communication frequency 3D FFT algorithm for ultra-large-scale micromagnetics simulation, Comput. Phys. Commun., 207, pp. 217-220, (2016); Scholz W., Et al., Scalable parallel micromagnetic solvers for magnetic nanostructures, Comput. Mater. Sci., 28, pp. 366-383, (2003); Fu S., Cui W., Hu M., Chang R., Donahue M.J., Lomakin V., Finitedifference micromagnetic solvers with the object oriented micromagnetic framework on graphics processing units, IEEE Trans. Magn., 52, 4, pp. 1-9, (2015); Vansteenkiste A., Et al., The design and verification of mumax3, AIP Adv., 4, 10, (2014)","A. Venugopal; Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, United States; email: venug012@umn.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","23798793","","","","English","IEEE J. Multiscale Multiphys. Comp. Tech.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85123729993" +"Pathak P.; Mallick D.","Pathak, Pankaj (57225689421); Mallick, Dhiman (56412544500)","57225689421; 56412544500","Size-Dependent Magnetization Switching in Magnetoelectric Heterostructures for Self-Biased MRAM Applications","2021","IEEE Transactions on Electron Devices","68","9","9463423","4418","4424","6","13","10.1109/TED.2021.3088079","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85112404268&doi=10.1109%2fTED.2021.3088079&partnerID=40&md5=1beef06ba168160edd4acef4e3cee9ec","Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India","Pathak P., Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India; Mallick D., Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India","Straintronic magnetic random access memory (MRAM) devices based on magnetoelectric heterostructures are gaining much attention because of their ability to perform energy-efficient, nonvolatile magnetization switching. However, practical applications of such devices are often restricted by the requirement of biasing magnetic field to provide the initial magnetization state. This work reports the self-biased, in-plane 180° magnetization switching of FeGaB nanomagnets on PMN-PT piezoelectric substrate. By varying the thickness of the nanomagnets with different aspect ratio, the self-biased operation is obtained for a particular range where the lower limit is imposed by the thermal stability and the upper limit is given by the shape anisotropy energy. We also demonstrate that in-plane 180° magnetization switching for larger aspect ratio nanomagnets is also limited because of the maximum achievable stress from the piezoelectric layer. The underlying physics, including the relationship between the critical switching time and energy, is delineated using finite difference method (FDM) micromagnetic model coupled with elastodynamic and electrostatic conditions. © 1963-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnetic random access memory (MRAM); magnetization; magnetoelectric; micromagnetic; self-biasing; straintronics","Aspect ratio; Energy efficiency; Finite difference method; Gallium compounds; Iron compounds; Magnetic recording; Magnetization; MRAM devices; Nanomagnetics; Piezoelectricity; Random access storage; Switching; Electrostatic conditions; Energy efficient; Finitedifference methods (FDM); Magnetic random access memory; Magnetization switching; Micromagnetic modeling; Piezoelectric layers; Piezoelectric substrates; Magnetic storage","","","","","Science and Engineering Research Board, SERB, (SRG/2019/002107); Indian Institute of Technology Delhi, IIITD","Manuscript received May 20, 2021; accepted June 7, 2021. Date of publication June 23, 2021; date of current version August 23, 2021. This work was supported in part by the Science and Engineering Research Board (SERB), Government of India, Start-up Research Grant under Project SRG/2019/002107 and in part by the Indian Institute of Technology Delhi (IIT Delhi). The review of this article was arranged by Editor B. K. Kaushik. (Corresponding author: Dhiman Mallick.) The authors are with the Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India (e-mail: dhiman.mallick@ee.iitd.ac.in).","Lang L., Et al., A low temperature functioning cofeb/mgo-based perpendicular magnetic tunnel junction for cryogenic nonvolatile random access memory, Appl. Phys. Lett, 116, 2, (2020); Brink Den A.Van., Et al., Spin-hall-assisted magnetic random access memory, Appl. Phys. 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Electron Devices, 63, 8, pp. 3307-3313, (2016); Lattery D.M., Zhang D., Zhu J., Hang X., Wang J.-P., Wang X., Low gilbert damping constant in perpendicularly magnetized w/cofeb/mgo films with high thermal stability, Sci. Rep, 8, 1, (2018); Lou J., Liu M., Reed D., Ren Y., Sun N.X., Giant electric field tuning of magnetism in novel multiferroic fegab/lead zinc niobate-lead titanate (pzn-pt) heterostructures, Adv. Mater, 21, 46, pp. 4711-4715, (2009); Vansteenkiste A., Wiele De B.Van., Mumax: A new high-performance micromagnetic simulation tool, J. Magn. Magn. Mater, 323, 21, pp. 2585-2591, (2011); Xiao Z., Et al., Bi-directional coupling in strain-mediated multiferroic heterostructures with magnetic domains and domain wall motion, Sci. Rep, 8, 1, (2018); Martinez E., Lopez-Diaz L., Torres L., Tristan C., Alejos O., Thermal effects in domain wall motion: Micromagnetic simulations and analytical model, Phys. Rev. B, Condens. Matter, 75, 17, (2007); Lou J., Insignares R.E., Cai Z., Ziemer K.S., Liu M., Sun N.X., Soft magnetism, magnetostriction, and microwave properties of fegab thin films, Appl. Phys. Lett, 91, 18, (2007); Beleggia M., Graef M.D., Millev Y.T., Goode D.A., Rowlands G., Demagnetization factors for elliptic cylinders, J. Phys. D, Appl. Phys, 38, 18, pp. 3333-3342, (2005); Kim J., Et al., Spin-based computing: Device concepts, current status, and a case study on a high-performance microprocessor, Proc. Ieee, 103, 1, pp. 106-130, (2015); Dubowik J., Shape anisotropy of magnetic heterostructures, Phys. Rev. B, Condens. Matter, 54, 2, pp. 1088-1091, (1996); Flovik V., MacIa F., Hernandez J.M., Brucas R., Hanson M., Wahlstrom E., Tailoring the magnetodynamic properties of nanomagnets using magnetocrystalline and shape anisotropies, Phys. Rev. B, Condens. Matter, 92, 10, (2015); Liang C.-Y., Sepulveda A.E., Hoff D., Keller S.M., Carman G.P., Strain-mediated deterministic control of 360- domain wall motion in magnetoelastic nanorings, J. Appl. Phys, 118, 17, (2015); Sohn H., Et al., Electrically driven magnetic domain wall rotation in multiferroic heterostructures to manipulate suspended on-chip magnetic particles, Acs Nano, 9, 5, pp. 4814-4826, (2015); Liu M., Et al., Electrically controlled non-volatile switching of magnetism in multiferroic heterostructures via engineered ferroelastic domain states, Npg Asia Mater, 8, 9, (2016)","D. Mallick; Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India; email: dhiman.mallick@ee.iitd.ac.in","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-85112404268" +"Jiang Y.; Zhou H.; Zhu D.; Wang C.; Wang Z.; Zhao W.","Jiang, Yuhao (57218697553); Zhou, Hangyu (57210570812); Zhu, Daoqian (57198653900); Wang, Chao (55887796300); Wang, Zhaohao (55826590200); Zhao, Weisheng (57198598095)","57218697553; 57210570812; 57198653900; 55887796300; 55826590200; 57198598095","Computational Study for Spin-orbit Torque Magnetic Random Access Memory","2021","Technical Digest - International Electron Devices Meeting, IEDM","2021-December","","","8.2.1","8.2.4","","7","10.1109/IEDM19574.2021.9720624","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85126955539&doi=10.1109%2fIEDM19574.2021.9720624&partnerID=40&md5=f747af881fc0b644c50156accd76d28e","Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China","Jiang Y., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China; Zhou H., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China; Zhu D., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China; Wang C., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China; Wang Z., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China; Zhao W., Fert Beijing Institute, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China","We provide the first comprehensive computational study of spin-orbit torque magnetic random access memory (SOT-MRAM) device. A framework combining ab initio and micromagnetic/macrospin simulations is proposed to probe into the key performances of SOT-MRAM device, i.e., the power consumption, read error rate and speed. Specifically, using density functional theory (DFT) coupled with maximally localized Wannier function (MLWF) and non-Equilibrium Green's function (NEGF), we calculate the intrinsic spin Hall conductivity (SHC) and the tunneling magnetoresistance (TMR) of SOT magnetic tunnel junctions (MTJs). Based on the SHC results and related experimental parameters, we analyze the write performance by Landau-Lifshitz-Gilbert (LLG) equation. Under this computational framework, we show that IrMn with broken magnetic symmetry is promising to satisfy the requirements for high performance SOT-MRAM. Our work paves the way to exploit new materials and optimize SOT-MRAM, which will accelerate both the theoretical and the related experimental research. © 2021 IEEE.","","Computation theory; Magnetic recording; Manganese alloys; MRAM devices; Tunnel junctions; Tunnelling magnetoresistance; Ab initio; Computational studies; Density-functional-theory; Localised; Magnetic random access memory; Micromagnetics; Performance; Read error rate; Spin orbits; Wannier functions; Density functional theory","","","","","Beijing Municipal Science and Technology Commission, BMSTC, (Z201100004220002); National Key Research and Development Program of China, NKRDPC, (2018YFB0407602); Academic Excellence Foundation of BUAA for PHD Students","ACKNOWLEDGMENT The authors gratefully acknowledge the National Key R&D Program of China (No. 2018YFB0407602), the Beijing Municipal Science and Technology Project (No. Z201100004220002) and the Academic Excellence Foundation of BUAA for PhD Students, for their financial support of this work.","Grimaldi E., Et al., Nat. Nanotechnol, 15, pp. 111-117, (2020); Liao Y.C., Et al., IEEE Int. Electron Devices Meet. IEDM, pp. 1361-1364, (2020); Cai W., Et al., IEEE Electron Device Lett, 42, pp. 704-707; Liu L., Et al., Nat. Nanotechnol, 16, 2021, pp. 277-282; Qiao J., Et al., Phys. Rev. B, 98, (2018); Taylor J., Et al., Phys. Rev. B, 63, (2001); Zhou J., Et al., Sci. China Phys. Mech, 63, (2020); Peng S., Et al., Adv. Electron. Mater, 5, (2019); Garello K., Et al., IEEE Symp. on VLSI Circuit, pp. 194-195, (2019); Oh Y.W., Et al., Nat. Nanotechnol, 11, pp. 878-884, (2016); Honjo H., Et al., IEEE Int. Electron Devices Meet. IEDM, pp. 2851-2854, (2019); Shi S., Et al., Phys. Rev. Appl, 9, (2018); Zhu L., Et al., Adv. Electron. Mater, 6, (2020); Zhu D., Et al., Phys. Rev. Appl, 13, (2020); Lee D., Et al., Sci. Rep, 10, (2020); Taniguchi T., Et al., Phys. Rev. B, 100, (2019)","","","Institute of Electrical and Electronics Engineers Inc.","","2021 IEEE International Electron Devices Meeting, IEDM 2021","11 December 2021 through 16 December 2021","San Francisco","177615","01631918","978-166542572-8","TDIMD","","English","Tech. Dig. Int. Electron Meet. IEDM","Conference paper","Final","","Scopus","2-s2.0-85126955539" +"Toledo D.; Navarrete B.; Stone M.; Luongo K.; Wang P.; Liang P.; Khizroev S.","Toledo, Dennis (57210844951); Navarrete, Brayan (57201214734); Stone, Mark (57188657142); Luongo, Kevin (14828230600); Wang, Ping (57190179819); Liang, Ping (57206239109); Khizroev, Sakhrat (56218602600)","57210844951; 57201214734; 57188657142; 14828230600; 57190179819; 57206239109; 56218602600","A theoretical study of switching energy efficiency in sub-10-nm spintronic devices","2020","Journal of Magnetism and Magnetic Materials","494","","165776","","","","1","10.1016/j.jmmm.2019.165776","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85071691610&doi=10.1016%2fj.jmmm.2019.165776&partnerID=40&md5=e733b2c8a7dceb5f477556b844a56679","Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States; Department of Electrical & Computer Engineering, Florida International University, Miami, 33174, FL, United States; Department of Electrical & Computer Engineering, University of California, Riverside, 92521, CA, United States","Toledo D., Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States, Department of Electrical & Computer Engineering, Florida International University, Miami, 33174, FL, United States; Navarrete B., Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States; Stone M., Department of Electrical & Computer Engineering, Florida International University, Miami, 33174, FL, United States; Luongo K., Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States; Wang P., Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States, Department of Electrical & Computer Engineering, Florida International University, Miami, 33174, FL, United States; Liang P., Department of Electrical & Computer Engineering, University of California, Riverside, 92521, CA, United States; Khizroev S., Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, FL, United States, Department of Electrical & Computer Engineering, Florida International University, Miami, 33174, FL, United States","Spin-transfer torque (STT) magnetic tunnel junctions (MTJs) in the sub-10-nm size range have shown enhancement in energy efficiency. This improved switching energy efficiency means a longer spin relaxation time, a corresponding stronger spin accumulation, and a resulting lower switching current density. This improvement in switching energy efficiency stems from a reduction in damping as the device size is reduced. This can be seen by a reduction in the damping constant in the Landau-Lifshitz Gilbert (LLG) equation. This term can take a range of values, and this range depends on the different contributions from the surface relative to the bulk. Specifically, at such small sizes the damping constant differs from the bulk damping constant. In this study, a detailed equation defining this surface-to-volume relative contribution was developed. This theory was tested through simulations involving a sub-10-nm cobalt cube utilizing the Object Oriented Micromagnetic Framework (OOMMF). These simulations showed a longer spin relaxation time with a decrease in device size (defined by side length) as well as a reduction in switching current density with a decrease in side length. This reduction in switching current density was approximately logarithmic versus volume, surface area, and side length. Moreover, in the sub-5-nm range, this reduction was nearly linear with respect to side length. These results agree with theoretical predictions and they are aligned with the experimentally demonstrated quantum size effect. © 2019 Elsevier B.V.","Damping constant; Spin relaxation time; Spin-transfer torque; Switching energy efficiency","Current density; Damping; Magnetic devices; Relaxation time; Switching; Tunnel junctions; Damping constants; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Relative contribution; Spin relaxation time; Spin transfer torque; Switching current density; Switching energy; Energy efficiency","","","","","FIU High-Performance Computational; National Science Foundation, NSF, (ECCS-0939514, ECCS-1810270); Office of Naval Research, ONR, (11594311); Air Force Office of Scientific Research, AFOSR, (FA9550-18-1-0527)","Funding text 1: This work was partially supported by National Science Foundation ( NSF ) under awards # ECCS-1810270 and # ECCS-0939514 , Air Force Office of Scientific Research (AFOSR) under award # FA9550-18-1-0527 , and Office of Naval Research (ONR) under award # 11594311 . In addition, the authors would like to thank Dr. Cassian D’Cunha and the FIU High-Performance Computational (HPC) resource for providing computing resources to facilitate some of the OOMMF simulations. ; Funding text 2: This work was partially supported by National Science Foundation (NSF) under awards # ECCS-1810270 and # ECCS-0939514, Air Force Office of Scientific Research (AFOSR) under award # FA9550-18-1-0527, and Office of Naval Research (ONR) under award # 11594311. In addition, the authors would like to thank Dr. Cassian D'Cunha and the FIU High-Performance Computational (HPC) resource for providing computing resources to facilitate some of the OOMMF simulations.","Ikeda S., Miura K., Yamamoto H., Mizunuma K., Gan H.D., Endo M., Kanai S., Hayakawa J., Matsukura F., Ohno H., Nat. Mater., 9, pp. 721-724, (2010); Donahue M.J., Porter D.G.; Dormand J.R., Prince P.J., J. Comput. Appl. 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B, 84, pp. 1-5, (2011); Dao N., Donahue M.J., Dumitru I., Spinu L., Whittenburg S.L., Lodder J.C., Nanotechnology, 15, pp. S634-S638, (2004); Ashby M.F., Ferreira P.J., Schodek D.L., Nanomaterials, Nanotechnologies, And Design An Introduction for Engineers and Architects, pp. 177-197, (2009); Johnson M., Spin injection, accumulation, and relaxation in Metals, Handbook of Spin Transport and Magnetism, pp. 115-136, (2012); Hong J., Hadjikhani A., Stone M., Allen F.I., Safonov V., Liang P., Bokor J., Khizroev S., IEEE Trans. Magn., 52, 7, (2016); Safonov V., Nonequilibrium Magnons: Theory, Experiment and Applications, (2012); Temple R.C., McLaren M., Brydson R.M.D., Hickey B.J., Marrows C.H., Sci. Rep-UK., 6, 28296, pp. 1-8, (2016)","S. Khizroev; Department of Electrical & Computer Engineering, University of Miami, Coral Gables, 33146, United States; email: skhizroev@miami.edu","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85071691610" +"Mokkath J.H.","Mokkath, Junais Habeeb (55037410600)","55037410600","Skyrmion formation and dynamics in magnetic bilayers via atomistic spin dynamics simulations","2021","Physica E: Low-Dimensional Systems and Nanostructures","130","","114720","","","","2","10.1016/j.physe.2021.114720","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85102511685&doi=10.1016%2fj.physe.2021.114720&partnerID=40&md5=5ca3379908c07f4ac044dff1b696a19c","Quantum Nanophotonics Simulations Lab, Department of Physics, Kuwait College of Science and Technology, 7th Ring Road, P.O. Box 27235, Kuwait","Mokkath J.H., Quantum Nanophotonics Simulations Lab, Department of Physics, Kuwait College of Science and Technology, 7th Ring Road, P.O. Box 27235, Kuwait","Magnetic skyrmions are topologically protected and stable nanoscale spin textures with a whirling configuration attractive for ultra-dense and low-power spintronics applications. Here, with the aid of an atomistic spin dynamics formalism using Landau-Lifshitz-Gilbert (LLG) simulations and Dzyaloshinskii-Moriya interaction (DMI) effects, we study the skyrmion formation and dynamics in magnetic bilayer structures as a function of the size, external magnetic field, temperature and simulation time. According to our calculations, in the absence of an external magnetic field and for temperature in the range of 10 K–30 K, the spin distribution is fully contributed by the spin-spiral structures. With the incorporation of an external magnetic field in the range of 1 T–6 T (T represents Tesla) and for temperature in the range of 10 K–30 K, we find phase transformation of spin-spiral structures into ordered skyrmion lattice confirming the succession of phases recently reported in experiments. Besides, we find that the skyrmion size and the total skyrmion number depends on the strength of the external magnetic field. Our theoretical results will help to understand the skyrmion formation and dynamics at finite temperatures and magnetic fields and help in the design of skyrmion materials. © 2021 Elsevier B.V.","Bilayer structures; Dzyaloshinskii-Moriya interaction; Landau-Lifshitz-Gilbert equation; Magnetic skyrmions","Magnetic field effects; Textures; Atomistics; Bi-layer structure; Dynamics simulation; Dzyaloshinskii-Moriya interaction; External magnetic field; Landau-Lifshitz-Gilbert equations; Magnetic bilayer; Magnetic skyrmion; Skyrmions; Spin spiral structures; Spin dynamics","","","","","","","Fert A., Reyren N., Cros V., Magnetic skyrmions: advances in physics and potential applications, Nat. Rev. Mater., 2, (2017); Casiraghi A., Corte-Leon H., Vafaee M., Garcia-Sanchez F., Durin G., Pasquale M., Jakob G., Klaui M., Kazakova O., Individual skyrmion manipulation by local magnetic field gradients, Commun. Phys., 2, (2019); Kiselev N.S., Bogdanov A.N., Schafer R., Rossler U.K., Chiral skyrmions in thin magnetic films: new objects for magnetic storage technologies?, J. Phys. D Appl. Phys., 44, (2011); Ma C., Zhang X., Xia J., Ezawa M., Jiang W., Ono T., Piramanayagam S.N., Morisako A., Zhou Y., Liu X., Electric field-induced creation and directional motion of domain walls and skyrmion bubbles, Nano Lett., 19, pp. 353-361, (2019); Li S., Kang W., Zhang X., Nie T., Zhou Y., Wang K.L., Zhao W., Magnetic skyrmions for unconventional computing, Mater. Horiz., (2021); Sampaio J., Cros V., Rohart S., Thiaville A., Fert A., Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures, Nat. 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Mater., 138, pp. 255-269, (1994)","","","Elsevier B.V.","","","","","","13869477","","PELNF","","English","Phys E","Article","Final","","Scopus","2-s2.0-85102511685" +"Edathumkandy Y.K.; Sztenkiel D.","Edathumkandy, Yadhu K. (57231520400); Sztenkiel, Dariusz (9332783600)","57231520400; 9332783600","Comparative study of magnetic properties of Mn3+ magnetic clusters in GaN using classical and quantum mechanical approach","2022","Journal of Magnetism and Magnetic Materials","562","","169738","","","","3","10.1016/j.jmmm.2022.169738","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85135413259&doi=10.1016%2fj.jmmm.2022.169738&partnerID=40&md5=6f9ea40230a71db6ced5d0ddd5054bf3","Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw, PL 02-668, Poland","Edathumkandy Y.K., Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw, PL 02-668, Poland; Sztenkiel D., Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, Warsaw, PL 02-668, Poland","Currently, simulations of many-body quantum systems are known to be computationally too demanding to be solved on classical computers. The main problem is that the computation time and memory necessary for performing the calculations usually grow exponentially with the number of particles N. An efficient approach to simulate many-body quantum systems is the use of classical approximation. Such approach can reduce the overall computational complexity, but it usually encounters difficulties in proper reproduction of temperature-dependent properties of a investigated system due to neglect of spin quantization. Therefore, it is timely and important to assess the validity of the classical approximation. To this end, in this work, we compare the results of numerical calculations of small Mn3+ paramagnetic clusters in GaN, where the Mn spins are treated classically with those where they are treated quantum-mechanically (crystal field model). In the first case, we solve the Landau–Lifshitz–Gilbert (LLG) equation that describes the precessional dynamics of spins represented by classical vectors. On the other hand, in the crystal field model, the state of Mn3+ ion (d4 configuration with S=2, L=2) is characterized by the set of orbital and spin quantum numbers |mS,mL>. Particular attention is paid to use numerical parameters that ensure the same single ion magnetic anisotropy in both classical and quantum approximation. Finally, a detailed comparative study of magnetization M(H,T) as a function of the magnetic field H, temperature T, number of ions in a given cluster N and the strength of super-exchange interaction J, obtained from both approaches will be presented. © 2022 Elsevier B.V.","Crystal-field theory; Exchange interaction; Jahn–Teller effect; Landau–Lifshitz–Gilbert equation; Magnetic anisotropy","Cell proliferation; Gallium nitride; III-V semiconductors; Ions; Magnetic anisotropy; Magnetism; Manganese compounds; Quantum optics; Spin dynamics; Classical approximation; Comparatives studies; Computation time; Crystal field models; Crystal field theory; Landau-Lifshitz-Gilbert equations; Magnetic cluster; Many-body quantum systems; Quantum mechanical; Temperature-dependent properties; Exchange interactions","","","","","Narodowym Centrum Nauki, NCN, (2018/31/B/ST3/03438); Uniwersytet Warszawski, UW, (GB77-6); Institut de Cardiologie de Montréal, MHI; Interdyscyplinarne Centrum Modelowania Matematycznego i Komputerowego UW, ICM UW","We would like to thank M. Sawicki for proofreading of the manuscript and valuable suggestions. The work is supported by the National Science Centre (Poland) through project OPUS 2018/31/B/ST3/03438 . This research was carried out with the support of the Interdisciplinary Centre for Mathematical and Computational Modelling (ICM) University of Warsaw under grant no GB77-6","Brown K.L., Munro W.J., Kendon V.M., Using quantum computers for quantum simulation, Entropy, 12, 11, pp. 2268-2307, (2010); Zhou Y., Stoudenmire E.M., Waintal X., What limits the simulation of quantum computers?, Phys. Rev. X, 10, (2020); Meyer D.A., Quantum computing classical physics, Philos. Trans. R. Soc., 360, 1792, pp. 395-405, (2002); Foulkes W.M.C., Mitas L., Needs R.J., Rajagopal G., Quantum Monte Carlo simulations of solids, Rev. Modern Phys., 73, 1, (2001); Wilson K.G., Renormalization group and critical phenomena. I. Renormalization group and the Kadanoff scaling picture, Phys. Rev. B, 4, 9, (1971); Evans R.F.L., Fan W.J., Chureemart P., Ostler T.A., Ellis M.O.A., Chantrell R.W., Atomistic spin model simulations of magnetic nanomaterials, J. Phys.: Condens. Matter, 26, 10, (2014); Evans R.F.L., Atxitia U., Chantrell R.W., Quantitative simulation of temperature-dependent magnetization dynamics and equilibrium properties of elemental ferromagnets, Phys. Rev. B, 91, 14, (2015); Schlickeiser F., Ritzmann U., Hinzke D., Nowak U., Role of entropy in domain wall motion in thermal gradients, Phys. Rev. Lett., 113, (2014); Ellis M.O.A., Chantrell R.W., Switching times of nanoscale FePt: finite size effects on the linear reversal mechanism, Appl. Phys. Lett., 106, 16, (2015); Bender S.A., Skarsvag H., Brataas A., Duine R.A., Enhanced spin conductance of a thin-film insulating antiferromagnet, Phys. Rev. Lett., 119, (2017); Hinzke D., Nowak U., Domain wall motion by the magnonic spin seebeck effect, Phys. Rev. Lett., 107, (2011); Gosk J., Zajac M., Wolos A., Kaminska M., Twardowski A., Grzegory I., Bockowski M., Porowski S., Magnetic anisotropy of bulk GaN: Mn single crystals codoped with Mg acceptors, Phys. Rev. B, 71, 9, (2005); Wolos A., Wysmolek A., Kaminska M., Twardowski A., Bockowski M., Grzegory I., Porowski S., Potemski M., Neutral Mn acceptor in bulk GaN in high magnetic fields, Phys. Rev. B, 70, 24, (2004); Stefanowicz W., Sztenkiel D., Faina B., Grois A., Rovezzi M., Devillers T., d'Acapito F., Navarro-Quezada A., Li T., l Jakiela R., Et al., Structural and paramagnetic properties of dilute Ga1−xMnxN, Phys. Rev. B, 81, 23, (2010); Bonanni A., Sawicki M., Devillers T., Stefanowicz W., Faina B., Li T., Winkler T.E., Sztenkiel D., Navarro-Quezada A., Rovezzi M., Jakiela R., Grois A., Wegscheider M., Jantsch W., Suffczynski J., d'Acapito F., Meingast A., Kothleitner G., Dietl T., Experimental probing of exchange interactions between localized spins in the dilute magnetic insulator (Ga, Mn)N, Phys. Rev. B, 84, (2011); Sztenkiel D., Foltyn M., Mazur G.P., Adhikari R., Kosiel K., Gas K., Zgirski M., Kruszka R., Jakiela R., Li T., Et al., Stretching magnetism with an electric field in a nitride semiconductor, Nature Commun., 7, 1, pp. 1-9, (2016); Gas K., Domagala J.Z., Jakiela R., Kunert G., Dluzewski P., Piskorska-Hommel E., Paszkowicz W., Sztenkiel D., Winiarski M.J., Kowalska D., Szukiewicz R., Baraniecki T., Miszczuk A., Hommel D., Sawicki M., Impact of substrate temperature on magnetic properties of plasma-assisted molecular beam epitaxy grown (Ga, Mn)N, J. 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B, 72, 16, (2005); Sztenkiel D., Spin orbital reorientation transitions induced by magnetic field, (2022); Szwacki N.G., Majewski J.A., Dietl T., Aggregation and magnetism of Cr, Mn, and Fe cations in GaN, Phys. Rev. B, 83, 18, (2011); Sato K., Bergqvist L., Kudrnovsky J., Dederichs P.H., Eriksson O., Turek I., Sanyal B., Bouzerar G., Katayama-Yoshida H., Dinh V.A., Et al., First-principles theory of dilute magnetic semiconductors, Rev. Modern Phys., 82, 2, (2010); Kuz'min M.D., Shape of temperature dependence of spontaneous magnetization of ferromagnets: Quantitative analysis, Phys. Rev. Lett., 94, (2005); Bergqvist L., Bergman A., Realistic finite temperature simulations of magnetic systems using quantum statistics, Phys. Rev. Mater., 2, (2018); Woo C.H., Wen H., Semenov A.A., Dudarev S.L., Ma P.-W., Quantum heat bath for spin-lattice dynamics, Phys. Rev. B, 91, (2015); Barker J., Bauer G.E.W., Semiquantum thermodynamics of complex ferrimagnets, Phys. Rev. B, 100, (2019); Kormann F., Dick A., Hickel T., Neugebauer J., Rescaled Monte Carlo approach for magnetic systems: Ab initio thermodynamics of bcc iron, Phys. Rev. B, 81, (2010); Ma P.-W., Dudarev S.L., Longitudinal magnetic fluctuations in Langevin spin dynamics, Phys. Rev. B, 86, (2012); Kormann F., Dick A., Hickel T., Neugebauer J., Role of spin quantization in determining the thermodynamic properties of magnetic transition metals, Phys. Rev. B, 83, (2011)","D. Sztenkiel; Institute of Physics, Polish Academy of Sciences, Warsaw, Aleja Lotnikow 32/46, PL 02-668, Poland; email: sztenkiel@ifpan.edu.pl","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85135413259" +"Zhang K.; Zhang D.; Wang C.; Zeng L.; Wang Y.; Zhao W.","Zhang, Kaili (57215927099); Zhang, Deming (56564382300); Wang, Chengzhi (57205199758); Zeng, Lang (7401904358); Wang, You (56527471100); Zhao, Weisheng (57198598095)","57215927099; 56564382300; 57205199758; 7401904358; 56527471100; 57198598095","Compact Modeling and Analysis of Voltage-Gated Spin-Orbit Torque Magnetic Tunnel Junction","2020","IEEE Access","8","","9032097","50792","50800","8","72","10.1109/ACCESS.2020.2980073","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85082390034&doi=10.1109%2fACCESS.2020.2980073&partnerID=40&md5=f86b54c4b81140eb54bf6e0b571e2d43","Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China; School of Microelectronics, Beihang University, Beijing, 100191, China; School of Electrical and Information Engineering, Beihang University, Beijing, 100191, China","Zhang K., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China, School of Electrical and Information Engineering, Beihang University, Beijing, 100191, China; Zhang D., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China, School of Electrical and Information Engineering, Beihang University, Beijing, 100191, China; Wang C., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China, School of Electrical and Information Engineering, Beihang University, Beijing, 100191, China; Zeng L., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China; Wang Y., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China; Zhao W., Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China, School of Microelectronics, Beihang University, Beijing, 100191, China","Recently, experimental results have demonstrated that perpendicular magnetic tunnel junction (p-MTJ) with the antiferromagnetic(AFM)/ferromagnetic (FM)/oxide structure can achieve field-free spin-orbit torque (SOT) switching since the AFM metal strip can not only generate the SOT, but also provide an exchange bias (HEX), making it suitable for practical applications. However, owing to that the HEX is weak, such field-free SOT switching is incomplete, thus resulting in severe switching reliability. In addition, a large SOT switching current (ISOT) is also required, leading to high switching energy dissipation. In this paper, to address these issues, the voltage-controlled magnetic anisotropy (VCMA) is introduced to assist the SOT switching, and such novel switching method is referred as voltage-gated SOT (VGSOT). First, we develop a physics-based compact model for the three-terminal VGSOT-MTJ device, which includes three modules, i.e., the electrical module, the tunnel magnetoresistance module and the dynamic switching module. Then, the impact of the VCMA effect on the field-free SOT switching is investigated by solving a modified Landau-Lifshitz-Gilbert (LLG) equation with consideration of the VCMA, SOT and HEX. Simulation results show that thanks to the introduction of the VCMA effect, the critical ISOT can be reduced greatly, and the incomplete field-free SOT switching can be completed. With further analysis, we obtain a special switching condition, under which complete SOT field-free switching can be achieved with a shortest path and ultra-low power. Moreover, a novel write pulse scheme is proposed to achieve high speed and reliability. © 2013 IEEE.","antiferromagnetic; compact model; exchange bias; field-free SOT switching; high speed and reliability; p-MTJ; ultra-low power; VCMA; voltage-gated SOT","Antiferromagnetism; Bias voltage; Energy dissipation; Magnetic anisotropy; Reliability; Strip metal; Switching; Tunnel junctions; Tunnelling magnetoresistance; Antiferromagnetics; Compact model; Exchange bias; High Speed; Ultra low power; VCMA; Magnetic devices","","","","","Beihang Hefei Innovation Research Institute, (BHKX-19-01, BHKX-19-02); National Natural Science Foundation of China, NSFC, (61901017); China Postdoctoral Science Foundation, (2018M641153); National Postdoctoral Program for Innovative Talents, (BX20180028)","This work was supported in part by the National Postdoctoral Program for Innovation Talents under Grant BX20180028, in part by the China Postdoctoral Science Foundation Funded Project under Grant 2018M641153, in part by the National Science Foundation of China Project under Grant 61901017, and in part by the Beihang Hefei Innovation Research Institute Project under Grant BHKX-19-01 and Grant BHKX-19-02.","Wang M., Cai W., Zhu D., Wang Z., Kan J., Zhao Z., Cao K., Wang Z., Zhang Y., Zhang T., Park C., Wang J.-P., Fert A., Zhao W., Fieldfree switching of a perpendicular magnetic tunnel junction through the interplay of spin orbit and spin-transfer torques, Nature Electron., 1, 11, pp. 582-588, (2018); Fong X., Kim Y., Venkatesan R., Choday S.H., Raghunathan A., Roy K., Spin-transfer torque memories: Devices, circuits, and systems, Proc. 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Phys., 41, 5, pp. 1915-1921, (1970); Lee H., Lee A., Wang S., Ebrahimi F., Gupta P., Amiri P.K., Wang K.L., Analysis and compact modeling of magnetic tunnel junctions utilizing voltage-controlled magnetic anisotropy, IEEE Trans. Magn., 54, 4, pp. 1-9, (2018); Kang W., Ran Y., Zhang Y., Lv W., Zhao W., Modeling and exploration of the voltage-controlled magnetic anisotropy effect for the next-generation low-power and high-speed MRAM applications, IEEE Trans. Nanotechnol., 16, 3, pp. 387-395, (2017); Kazemi M., Rowlands G.-E., Ipek E., Buhrman R.-A., Friedman E.-G., Compact model for spin-orbit magnetic tunnel junctions, IEEE Trans. Electron Devices, 63, 2, pp. 848-855, (2016); Long M., Zeng L., Gao T., Zhang D., Qin X., Zhang Y., Zhao W., Self-adaptive write circuit for magnetic tunneling junction memory with voltage-controlled magnetic anisotropy effect, IEEE Trans. Nanotech-nol., 17, 3, pp. 492-499, (2018)","D. Zhang; Hefei Innovation Research Institute, Beihang University, Hefei, 230013, China; email: deming.zhang@buaa.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","21693536","","","","English","IEEE Access","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85082390034" +"Bazaev E.A.; Bazaev A.R.; Osmanova B.K.; Dzhapparov T.A.G.","Bazaev, E.A. (6602077040); Bazaev, A.R. (6603744258); Osmanova, B.K. (57198779325); Dzhapparov, T.A.G. (57188746026)","6602077040; 6603744258; 57198779325; 57188746026","Phase transitions of n-Hexane-Water binary mixtures (0.5 mole fraction)","2020","Journal of Physics: Conference Series","1683","3","032031","","","","1","10.1088/1742-6596/1683/3/032031","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85099556616&doi=10.1088%2f1742-6596%2f1683%2f3%2f032031&partnerID=40&md5=2e873f755d6faefbb7557bc2fe9dffca","Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Shamilya, 39 a, Makhachkala, 367030, Russian Federation","Bazaev E.A., Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Shamilya, 39 a, Makhachkala, 367030, Russian Federation; Bazaev A.R., Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Shamilya, 39 a, Makhachkala, 367030, Russian Federation; Osmanova B.K., Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Shamilya, 39 a, Makhachkala, 367030, Russian Federation; Dzhapparov T.A.G., Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Shamilya, 39 a, Makhachkala, 367030, Russian Federation","By the method of constant volume piezometer among the isochores new values of p, T and p, p, T - relations of n-hexane- water binary mixture (0.5 mole fraction) in three phase (llg) and two phase (ll and lg, l-liquid, g - gas) regions, over the wide temperature range from 373.15 to 673.15 K, pressures between 0.2 and 56 MPa and densities between 55 kg/m3and 554 kg/m3are obtained. Using isochoric P-T break point technique the values of the phase transition parameters (llg⇄ll, llg⇄lg and ll⇄lg) on p, T - plane were determined and phase coexistence curves in different thermodynamic sections (p,p,T)x were built. The dependence of pressure from temperature, density and composition along the phase coexistence curve is described by three parameter polynomial represented by expansion of the compressibility factor Zs=psVms/RTs=ps/RTsρms into a power series of density ω=ps/pc and temperature τ=Ts/Tc.{equation presented}, where ρmmolar density (mol/m3), R=8.314-gas constant (J/mol·K). The average relative deviation of calculated values of pressure from experimental ones is not more than 0.1%. © 2020 Institute of Physics Publishing. All rights reserved.","","Hexane; Phase transitions; Temperature; Thermal Engineering; Calculated values; Compressibility factor; Constant-volume piezometers; Phase co-existence; Relative deviations; Three parameters; Transition parameter; Wide temperature ranges; Binary mixtures","","","","","Russian Fund of Basic Researches, (18-08-00124 А)","The study has been support by Russian Fund of Basic Researches (Project №18-08-00124 А)","Stanly G, Phase transitions and critical phenomena, (1973); Smirnova N A, Molecular theory of solutions, (1987); Durov V A, Ageev Ye P, Thermodynamic theory of solutions, (2003); Walas Stanley M, Phase equilibria in Chemical engineering, (1989); Walas Stanley M, Phase equilibria in Chemical engineering, (1989); NIST Chemistry WebBook; Abdulagatov I M, Bazaev A R, Bazaev E A, Dzhapparov T A, The J. of Supercritical Fluids, 117, pp. 172-193, (2016); Yiling T, Michelberger Th, Franck E U, J.Chem. Thermodynamics, 23, pp. 105-112, (1991); Charles J R, Kenneth E H, A.I.Ch.E. J. January, 13, 1, pp. 118-121, (1967); De Loos T W, Penders W G, Lichtenthaler R N, J. Chem. Thermodyn, 14, pp. 83-91, (1982); Brunner E, J. Chem. Thermodynamics, 22, pp. 335-353, (1990); Tsonopoulos C, Wilson G M, AIChE J, 29, pp. 990-999, (1983); Marche C, Ferronato C, Jose J, J. Chem. Eng. Data, 48, pp. 967-971, (2003); Mokraoui S, Coquelet C, Valtz A, Hegel P, Richon D, Ind. Eng. Chem. Res, 46, pp. 9257-9262, (2007); Smith G R, Fahy M J, Wormald C J, J. Chem. Thermodyn, 16, pp. 825-831, (1984); Barrufet M A, Liu K, Rahman S, Wu C, J. Chem. Eng. Data, 41, pp. 918-922, (1996); Antonio R, Ramy A N, Ilham M, Pierre D-S, Jacques J, Evelyne R, Charles B, J. Chem. Eng. Data, 55, 4, pp. 1468-1472, (2010); Selva P, Javeed A A, Amir H M, Alain V, Christophe C, Esteban A B, Dominique R, Fluid Phase Equilibria, 275, 1, pp. 52-59; Celine M, Corinne F, Jacques J, J. Chem. Eng. Data, 48, pp. 967-971, (2003); Abdurashidova A A, Bazaev A R, Bazaev E A, Abdulagatov I M, High Temp, 45, 2, pp. 178-186, (2007); Bazaev E A, Bazaev A R, Abdurashidova A A, High Temp, 47, (2009); Karabekova B K, Bazaev E A, Bazaev A R, Russian J. of Phys. Chem. B, 89, 9, pp. 1386-1396, (2015); Sychev V V, Vasserman A A, Thermodynamic properties of nitrogen, (1977)","E.A. Bazaev; Institute of Geothermal Research and Renewable Energy the Branch of JIHT RAS, Makhachkala, Shamilya, 39 a, 367030, Russian Federation; email: emilbazaev@gmail.com","","IOP Publishing Ltd","","3rd Conference on Problems of Thermal Physics and Power Engineering, PTPPE 2020","19 October 2020 through 23 October 2020","Moscow","166435","17426588","","","","English","J. Phys. Conf. Ser.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85099556616" +"Tauki M.S.Y.; Hassan O.","Tauki, Md. Sadik Yasir (58196826000); Hassan, Orchi (57198191767)","58196826000; 57198191767","Modeling Second Order Anisotropy of Monodomain Magnetic Body","2022","12th International Conference on Electrical and Computer Engineering, ICECE 2022","","","","441","444","3","0","10.1109/ICECE57408.2022.10088553","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85153581682&doi=10.1109%2fICECE57408.2022.10088553&partnerID=40&md5=d7ba261ecc53b30ee844b57c651d39c8","Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh","Tauki M.S.Y., Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh; Hassan O., Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh","The switching of a ferromagnet's magnetization direction is a fundamental aspect in modeling spintronic devices. The switching can be achieved by applying an external magnetic field or spin current, and one of the key determinants of the switching process is the magnetocrystalline anisotropy. To model the magnetization dynamics, considering only the first order magnetocrystalline perpendicular anisotropy contributions had been sufficient thus far as it's contributions are predominant. However, as the dimensions of the magnetic body are scaled down, or subject to voltage control of anisotropy (VCMA) effect, the magnetocrystalline perpendicular anisotropy and the out-of-plane demagnetizing field both end up having equal order, and nowadays low barrier magnets are purposefully designed to have magnetic anisotropy close to zero for special applications. In these cases, the contribution of the second order anisotropy of the ferromagnet need to be considered while studying the magnetization dynamics. In this paper, we developed a physics-based SPICE-compatible compact model of a monodomain magnetic body considering the second-order magnetic anisotropy contributions. The magnetization dynamics are described by the stochastic Landau-Lifshitz-Gilbert (sLLG) equation and can be used to study both perpendicular magnetic anisotropy (PMA) magnets and in-plane magnetic anisotropy (IMA) magnets. Here, we studied the effect of second order anisotropy in the critical switching field and current for PMA magnet and found that the second-order contributions to the switching field and current become significant when it is in the same order as the first order anisotropy. © 2022 IEEE.","LLG; PMA; Second order anisotropy; SPICE; VCMA","Dynamics; Ferromagnetic materials; Ferromagnetism; SPICE; Superconducting materials; 'spice'; Ferromagnets; LLG; Magnetization dynamics; Monodomains; Order anisotropy; Perpendicular magnetic anisotropy; Second order anisotropy; Second orders; VCMA; Stochastic systems","","","","","","","Tehrani S., Slaughter J., Chen E., Durlam M., Shi J., DeHerren M., Progress and outlook for mram technology, IEEE Transactions on Magnetics, 35, 5, pp. 2814-2819, (1999); Tehrani S., Engel B., Slaughter J., Chen E., DeHerrera M., Durlam M., Naji P., Whig R., Janesky J., Calder J., Recent developments in magnetic tunnel junction mram, IEEE Transactions on magnetics, 36, 5, pp. 2752-2757, (2000); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Physical Review B, 62, 1, (2000); Panagopoulos G., Augustine C., Roy K., A framework for simulating hybrid mtj/cmos circuits: Atoms to system approach, 2012 Design, Automation & Test in Europe Conference & Exhibition (DATE), pp. 1443-1446, (2012); Nozaki T., Yamamoto T., Tamaru S., Kubota H., Fukushima A., Suzuki Y., Yuasa S., Enhancement in the interfacial perpendicular magnetic anisotropy and the voltage-controlled magnetic anisotropy by heavy metal doping at the fe/mgo interface, APL Materials, 6, 2, (2018); Camsari K.Y., Sutton B.M., Datta S., P-bits for probabilistic spin logic, Applied Physics Reviews, 6, 1, (2019); Hassan O., Faria R., Camsari K.Y., Sun J.Z., Datta S., Low-barrier magnet design for effcient hardware binary stochastic neurons, IEEE Magnetics Letters, 10, pp. 1-5, (2019); Bruno P., Tight-binding approach to the orbital magnetic moment and magnetocrystalline anisotropy of transition-metal monolayers, Physical Review B, 39, 1, (1989); Neel L., Anisotropie magnétique superfcielle et surstructures d'orientation, Journal de Physique et le Radium, 15, 4, pp. 225-239, (1954); Shaw J.M., Nembach H.T., Silva T.J., Measurement of orbital asymmetry and strain in co 90 fe 10/ni multilayers and alloys: Origins of perpendicular anisotropy, Physical Review B, 87, 5, (2013); Gweon H.K., Park H.-J., Kim K.-W., Lee K.-J., Lim S.H., Intrinsic origin of interfacial second-order magnetic anisotropy in fer-romagnet/normal metal heterostructures, NPG Asia Materials, 12, 1, pp. 1-6, (2020); Camsari K.Y., Ganguly S., Datta S., Modular approach to spintronics, Scientifc reports, 5, 1, pp. 1-13, (2015); Makarov A., Modeling of Emerging Resistive Switching Based Memory Cells, (2014); Pinna D., Kent A., Stein D., Spin-transfer torque magnetization reversal in uniaxial nanomagnets with thermal noise, Journal of Applied Physics, 114, 3, (2013); Perna S., Tomasello R., Scimone T., D'Aquino M., Serpico C., Carpentieri M., Finocchio G., Infuence of the second-order uniaxial anisotropy on the dynamical proprieties of magnetic tunnel junctions, IEEE Transactions on Magnetics, 53, 4, pp. 1-7, (2016); Faria R., Camsari K.Y., Datta S., Low-barrier nanomagnets as p-bits for spin logic, IEEE Magnetics Letters, 8, pp. 1-5, (2017)","M.S.Y. Tauki; Bangladesh University of Engineering and Technology, Department of Electrical and Electronic Engineering, Dhaka, 1205, Bangladesh; email: sadikyasir@gmail.com","","Institute of Electrical and Electronics Engineers Inc.","","12th International Conference on Electrical and Computer Engineering, ICECE 2022","21 December 2022 through 23 December 2022","Dhaka","187762","","979-835039879-3","","","English","Int. Conf. Electr. Comput. Eng., ICECE","Conference paper","Final","","Scopus","2-s2.0-85153581682" +"Mauser N.J.; Pfeiler C.-M.; Praetorius D.; Ruggeri M.","Mauser, Norbert J. (7004158395); Pfeiler, Carl-Martin (57208439571); Praetorius, Dirk (6507452481); Ruggeri, Michele (56196953600)","7004158395; 57208439571; 6507452481; 56196953600","Unconditional well-posedness and IMEX improvement of a family of predictor-corrector methods in micromagnetics","2022","Applied Numerical Mathematics","180","","","33","54","21","3","10.1016/j.apnum.2022.05.008","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85130574235&doi=10.1016%2fj.apnum.2022.05.008&partnerID=40&md5=6b6af00ef2c3c03befcd56ca4982aba5","Research Platform MMM”Mathematics-Magnetism-Materials” c/o Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, Vienna, 1090, Austria; Institute of Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, Glasgow, G1 1XH, United Kingdom","Mauser N.J., Research Platform MMM”Mathematics-Magnetism-Materials” c/o Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, Vienna, 1090, Austria; Pfeiler C.-M., Institute of Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Praetorius D., Institute of Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Ruggeri M., Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, Glasgow, G1 1XH, United Kingdom","Recently, Kim & Wilkening (Convergence of a mass-lumped finite element method for the Landau–Lifshitz equation, Quart. Appl. Math., 76, 383–405, 2018) proposed two novel predictor-corrector methods for the Landau–Lifshitz–Gilbert equation (LLG) in micromagnetics, which models the dynamics of the magnetization in ferromagnetic materials. Both integrators are based on the so-called Landau–Lifshitz form of LLG, use mass-lumped variational formulations discretized by first-order finite elements, and only require the solution of linear systems, despite the nonlinearity of LLG. The first(-order in time) method combines a linear update with an explicit projection of an intermediate approximation onto the unit sphere in order to fulfill the LLG-inherent unit-length constraint at the discrete level. In the second(-order in time) integrator, the projection step is replaced by a linear constraint-preserving variational formulation. In this paper, we extend the analysis of the integrators by proving unconditional well-posedness and by establishing a close connection of the methods with other approaches available in the literature. Moreover, the new analysis also provides a well-posed integrator for the Schrödinger map equation (which is the limit case of LLG for vanishing damping). Finally, we design an implicit-explicit strategy for the treatment of the lower-order field contributions, which significantly reduces the computational cost of the schemes, while preserving their theoretical properties. © 2022 The Author(s)","Finite elements; Implicit-explicit time-marching scheme; Landau–Lifshitz–Gilbert equation; Micromagnetism; Unconditional well-posedness","Control nonlinearities; Ferromagnetic materials; Linear systems; Implicit-explicit; Implicit-explicit time-marching scheme; Landau-Lifshitz-Gilbert equations; Micromagnetics; Micromagnetisms; Predictor-corrector methods; Time marching schemes; Unconditional well-posedness; Variational formulation; Wellposedness; Finite element method","","","","","SEQUEX, (MA16-066); Vienna Science and Technology Fund, WWTF; Austrian Science Fund, FWF, (F65, P31140, W1245); Universität Wien","Acknowledgment. The authors thankfully acknowledge support by the Austrian Science Fund (FWF) through the doctoral school Dissipation and dispersion in nonlinear PDEs (grant W1245 ), the special research program Taming complexity in partial differential systems (grant F65 ), and the project Reduced order approaches for micromagnetics (grant P31140 ); by the Vienna Science and Technology Fund (WWTF) through the project Schrödinger Equations for QUantum EXperiments (SEQUEX) (grant MA16-066 ); and by the University of Vienna research platform MMM (”Mathematics-Magnetism-Materials”). Further, we thank Lukas Exl for fruitful discussions in the early stage of this work. ","Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suess D., Spin-polarized transport in ferromagnetic multilayers: an unconditionally convergent FEM integrator, Comput. Math. Appl., 68, 6, pp. 639-654, (2014); Akrivis G., Feischl M., Kovacs B., Lubich C., Higher-order linearly implicit full discretization of the Landau-Lifshitz-Gilbert equation, Math. Comput., 90, 329, pp. 995-1038, (2021); Alouges F., A new finite element scheme for Landau–Lifchitz equations, Discrete Contin. Dyn. Syst., Ser. S, 1, 2, pp. 187-196, (2008); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau–Lifshitz equation in micromagnetism, Math. Models Methods Appl. Sci., 16, 2, pp. 299-316, (2006); Alouges F., Soyeur A., On global weak solutions for Landau–Lifshitz equations: existence and nonuniqueness, Nonlinear Anal., 18, 11, pp. 1071-1084, (1992); Alouges F., Kritsikis E., Steiner J., Toussaint J.-C., A convergent and precise finite element scheme for Landau–Lifschitz–Gilbert equation, Numer. Math., 128, 3, pp. 407-430, (2014); An R., Optimal error estimates of linearized Crank-Nicolson Galerkin method for Landau-Lifshitz equation, J. Sci. Comput., 69, 1, pp. 1-27, (2016); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, 1, pp. 220-238, (2005); Bartels S., Numerical Methods for Nonlinear Partial Differential Equations, (2015); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau–Lifshitz–Gilbert equation, SIAM J. Numer. Anal., 44, 4, pp. 1405-1419, (2006); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation scheme for the Landau–Lifshitz–Gilbert equation, Math. Comput., 77, 262, pp. 773-788, (2008); Boffi D., Brezzi F., Fortin M., Mixed Finite Element Methods and Applications, (2013); Brown W.F., Micromagnetics, (1963); Bruckner F., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Ruggeri M., Suess D., Multiscale modeling in micromagnetics: existence of solutions and numerical integration, Math. Models Methods Appl. Sci., 24, 13, pp. 2627-2662, (2014); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in a bounded domain, Differ. Integral Equ., 14, 2, pp. 213-229, (2001); Chen J., Wang C., Xie C., Convergence analysis of a second-order semi-implicit projection method for Landau-Lifshitz equation, Appl. Numer. Math., 168, pp. 55-74, (2021); Cimrak I., A survey on the numerics and computations for the Landau–Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng., 15, 3, pp. 277-309, (2008); Cimrak I., Convergence result for the constraint preserving mid-point scheme for micromagnetism, J. Comput. Appl. Math., 228, 1, pp. 238-246, (2009); D'Aquino M., Serpico C., Miano G., Geometrical integration of Landau–Lifshitz–Gilbert equation based on the mid-point rule, J. Comput. Phys., 209, 2, pp. 730-753, (2005); Di Fratta G., Innerberger M., Praetorius D., Weak-strong uniqueness for the Landau–Lifshitz–Gilbert equation in micromagnetics, Nonlinear Anal., Real World Appl., 55, (2020); Di Fratta G., Pfeiler C.-M., Praetorius D., Ruggeri M., Stiftner B., Linear second-order IMEX-type integrator for the (Eddy current) Landau–Lifshitz–Gilbert equation, IMA J. Numer. Anal., 40, 4, pp. 2802-2838, (2020); Dumas E., Sueur F., On the weak solutions to the Maxwell–Landau–Lifshitz equations and to the Hall-Magneto-Hydrodynamic equations, Commun. Math. Phys., 330, 3, pp. 1179-1225, (2014); Feischl M., Tran T., The Eddy Current–LLG equations: FEM-BEM coupling and a priori error estimates, SIAM J. Numer. Anal., 55, 4, pp. 1786-1819, (2017); Feischl M., Tran T., Existence of regular solutions of the Landau-Lifshitz-Gilbert equation in 3D with natural boundary conditions, SIAM J. Math. Anal., 49, 6, pp. 4470-4490, (2017); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetization fields, IEEE Trans. Magn., 26, 2, pp. 415-417, (1990); Gao H., Optimal error estimates of a linearized backward Euler FEM for the Landau-Lifshitz equation, SIAM J. Numer. Anal., 52, 5, pp. 2574-2593, (2014); Garcia-Cervera C.J., Numerical micromagnetics: a review, Bol. Soc. Esp. Mat. Apl. SeMA, 39, pp. 103-135, (2007); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Guo B., Hong M.-C., The Landau–Lifshitz equation of the ferromagnetic spin chain and harmonic maps, Calc. Var. Partial Differ. Equ., 1, 3, pp. 311-334, (1993); Kim E., Lipnikov K., The mimetic finite difference method for the Landau-Lifshitz equation, J. Comput. Phys., 328, pp. 109-130, (2017); Kim E., Wilkening J., Convergence of a mass-lumped finite element method for the Landau–Lifshitz equation, Q. Appl. Math., 76, pp. 383-405, (2018); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev., 48, 3, pp. 439-483, (2006); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-168, (1935); Lin F., Wang C., The Analysis of Harmonic Maps and Their Heat Flows, (2008); Melcher C., Existence of partially regular solutions for Landau–Lifshitz equations in R3, Commun. Partial Differ. Equ., 30, 4, pp. 567-587, (2005); NIST micromagnetic modeling activity group (μMAG) website; Pfeiler C.-M., Ruggeri M., Stiftner B., Exl L., Hochsteger M., Hrkac G., Schoberl J., Mauser N.J., Praetorius D., Computational micromagnetics with commics, Comput. Phys. Commun., 248, (2020); Praetorius D., Ruggeri M., Stiftner B., Convergence of an implicit-explicit midpoint scheme for computational micromagnetics, Comput. Math. Appl., 75, 5, pp. 1719-1738, (2018); Prohl A., Computational Micromagnetism, (2001); Schoberl J., Netgen/NGSolve; Sulem P.L., Sulem C., Bardos C., On the continuous limit for a system of classical spins, Commun. Math. Phys., 107, 3, pp. 431-454, (1986); The Object Oriented MicroMagnetic Framework (OOMMF) project at ITL/NIST; Visintin A., On Landau–Lifshitz' equations for ferromagnetism, Jpn. J. Appl. Math., 2, 1, pp. 69-84, (1985); Wang X.-P., Garcia-Cervera C.J., E W., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys., 171, 1, pp. 357-372, (2001); Xie C., Garcia-Cervera C.J., Wang C., Zhou Z., Chen J., Second-order semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys., 404, (2020)","C.-M. Pfeiler; Institute of Analysis and Scientific Computing, TU Wien, Vienna, Wiedner Hauptstrasse 8–10, 1040, Austria; email: carl-martin.pfeiler@asc.tuwien.ac.at","","Elsevier B.V.","","","","","","01689274","","ANMAE","","English","Appl Numer Math","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85130574235" +"Di Fratta G.; Innerberger M.; Praetorius D.","Di Fratta, Giovanni (23093879900); Innerberger, Michael (57215597089); Praetorius, Dirk (6507452481)","23093879900; 57215597089; 6507452481","Weak–strong uniqueness for the Landau–Lifshitz–Gilbert equation in micromagnetics","2020","Nonlinear Analysis: Real World Applications","55","","103122","","","","17","10.1016/j.nonrwa.2020.103122","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85081650873&doi=10.1016%2fj.nonrwa.2020.103122&partnerID=40&md5=7d148c0a649c0e6f9e97c47a9821d70b","TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8–10/E101/4, Wien, 1040, Austria","Di Fratta G., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8–10/E101/4, Wien, 1040, Austria; Innerberger M., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8–10/E101/4, Wien, 1040, Austria; Praetorius D., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8–10/E101/4, Wien, 1040, Austria","We consider the time-dependent Landau–Lifshitz–Gilbert equation. We prove that each weak solution coincides with the (unique) strong solution, as long as the latter exists in time. Unlike available results in the literature, our analysis also includes the physically relevant lower-order terms like Zeeman contribution, anisotropy, stray field, and the Dzyaloshinskii–Moriya interaction (which accounts for the emergence of magnetic Skyrmions). Moreover, our proof gives a template on how to approach weak–strong uniqueness for even more complicated problems, where LLG is (nonlinearly) coupled to other (nonlinear) PDE systems. © 2020 Elsevier Ltd","Dzyaloshinskii–Moriya interaction; Landau–Lifshitz–Gilbert equation; Magnetic skyrmions; Micromagnetics; Weak–strong uniqueness","Lower order terms; Micromagnetics; Skyrmions; Stray field; Strong solution; Time dependent; Weak solution; Zeeman contribution; Applications","","","","","Austrian Science Fund, FWF, (SFB F65, W1245)","The authors acknowledge support through the Austrian Science Fund (FWF) through the doctoral school Dissipation and dispersion in nonlinear PDEs (grant W1245) and the special research program Taming complexity in PDE systems (grant SFB F65).","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, 11, pp. 1071-1084, (1992); Carbou G., Fabrie P., Regular solutions for Landau-Lifshitz equation in a bounded domain, Differential Integral Equations, 14, 2, pp. 213-229, (2001); Carbou G., Fabrie P., Regular solutions for Landau-Lifshitz equation in R3 , Commun. Appl. Anal., 5, 1, pp. 17-30, (2001); Melcher C., Global solvability of the Cauchy problem for the Landau-Lifshitz-Gilbert equation in higher dimensions, Indiana Univ. Math. J., 61, 3, pp. 1175-1200, (2012); Feischl M., Tran T., Existence of regular solutions of the Landau–Lifshitz–Gilbert equation in 3D with natural boundary conditions, SIAM J. Math. Anal., 49, 6, pp. 4470-4490, (2017); Prohl A., Computational Micromagnetism, Advances in Numerical Mathematics, (2001); Constantin P., Foias C., Navier-Stokes Equations, (1988); Ozanski W.S., Pooley B.C., Leray's fundamental work on the navier-Stokes equations: a modern review of “sur le mouvement d'un liquide visqueux emplissant l'espace”, Partial Differential Equations in Fluid Mechanics, London Math. Soc. Lecture Note Ser., 452, pp. 113-203, (2018); Dumas E., Sueur F., On the weak solutions to the Maxwell–Landau–Lifshitz equations and to the Hall–Magneto–Hydrodynamic equations, Comm. Math. Phys., 330, pp. 1179-1225, (2014); Kalousek M., Kortum J., Schlomerkemper A., Mathematical analysis of weak and strong solutions to an evolutionary model for magnetoviscoelasticity, (2019); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, 2, pp. 187-196, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-gilbert equation, SIAM J. Numer. Anal., 44, 4, pp. 1405-1419, (2006); Hrkac G., Pfeiler C.-M., Praetorius D., Ruggeri M., Segatti A., Stiftner B., Convergent tangent plane integrators for the simulation of chiral magnetic skyrmion dynamics, Adv. Comput. Math., 45, 3, pp. 1329-1368, (2019); Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suess D., Spin-polarized transport in ferromagnetic multilayers: an unconditionally convergent FEM integrator, Comput. Math. Appl., 68, 6, pp. 639-654, (2014); Di Fratta G., Pfeiler C.-M., Praetorius D., Ruggeri M., Stiftner B., Linear second-order IMEX-type integrator for the (eddy current) Landau-Lifshitz-gilbert equation, IMA J. Numer. Anal., (2019); Moffatt H.K., Helicity and singular structures in fluid dynamics, Proc. Natl. Acad. Sci. USA, 111, 10, pp. 3663-3670, (2014); Hardt R., Kinderlehrer D., Lin F.-H., Existence and partial regularity of static liquid crystal configurations, Comm. Math. Phys., 105, 4, pp. 547-570, (1986); Melcher C., Chiral skyrmions in the plane, Proc. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci., 470, (2014); Praetorius D., Analysis of the operator Δ−1div arising in magnetic models, Z. Anal. Anwend., 23, pp. 589-605, (2004); Di Fratta G., Muratov C.B., Rybakov F.N., Slastikov V.V., Variational principles of micromagnetics revisited, (2019); Carbou G., Fabrie P., Gues O., Couche limite dans un modèle de ferromagnétisme, Commun. Partial Differential Equations, 27, 7-8, pp. 1467-1495, (2007); Leoni G., A First Course in Sobolev Spaces, Graduate studies in mathematics, (2017); Evans L.C., Partial Differential Equations, (2010); Cimrak I., Existence, regularity and local uniqueness of the solutions to the Maxwell–Landau–Lifshitz system in three dimensions, J. Math. Anal. Appl., 329, 2, pp. 1080-1093, (2007)","M. Innerberger; TU Wien, Institute for Analysis and Scientific Computing, Wien, Wiedner Hauptstr. 8–10/E101/4, 1040, Austria; email: Michael.Innerberger@asc.tuwien.ac.at","","Elsevier Ltd","","","","","","14681218","","","","English","Nonlinear Anal. Real World Appl.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85081650873" +"Belrhazi H.; Hafidi M.Y.E.; Hafidi M.E.","Belrhazi, Hamza (57210117936); Hafidi, Moulay Youssef El (57215222039); Hafidi, Mohamed El (6603967073)","57210117936; 57215222039; 6603967073","Magnetization states driven by spin-transfer torque in spin-valve nanopillars in presence of four-fold magnetocrystalline anisotropy","2020","Journal of Magnetism and Magnetic Materials","510","","166929","","","","4","10.1016/j.jmmm.2020.166929","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85083745595&doi=10.1016%2fj.jmmm.2020.166929&partnerID=40&md5=f4a1e6dca75a307c115c00567d27b7b1","Condensed Matter Physics Laboratory, Department of Physics, Faculty of Science Ben M'sik, Hassan II University of Casablanca, D. El Harty Av., B.P 7955, Casablanca, 20165, Morocco","Belrhazi H., Condensed Matter Physics Laboratory, Department of Physics, Faculty of Science Ben M'sik, Hassan II University of Casablanca, D. El Harty Av., B.P 7955, Casablanca, 20165, Morocco; Hafidi M.Y.E., Condensed Matter Physics Laboratory, Department of Physics, Faculty of Science Ben M'sik, Hassan II University of Casablanca, D. El Harty Av., B.P 7955, Casablanca, 20165, Morocco; Hafidi M.E., Condensed Matter Physics Laboratory, Department of Physics, Faculty of Science Ben M'sik, Hassan II University of Casablanca, D. El Harty Av., B.P 7955, Casablanca, 20165, Morocco","In this work, the magnetization states under the spin-transfer switching effect are investigated in a nanopillar device composed of a half-metallic Heusler Co1.5Fe1.5Ge alloy with a four-fold in-plane magnetocrystalline anisotropy. A comparative study with a half-metallic Heusler alloy of Co2FeAl0.5Si0.5 and a typical material of Fe is realized by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation with the Spin-Transfer Torque (STT) contribution, using micromagnetic simulations. Our ultimate goal is to elucidate the origins of the intermediate state (IS) that occurs during magnetization switching by deeply examining the effects of magnetocrystalline anisotropy and shape anisotropy on the magnetization states through analyzing and comparing various switching processes. Our simulation results showed that the magnetization switching via a single-step under low current densities is possible at certain critical cross-sectional dimensions of the ellipse that are adjusted to increase the demagnetization field against the four-fold in-plane magnetocrystalline anisotropy. As well, we provided in this paper a set of appropriate geometric dimensions which allow the magnetization to reverse via a single-step by overcoming IS with minimal spin-polarized current densities. © 2020 Elsevier B.V.","Four-fold magnetocrystalline anisotropy; Intermediate state; Magnetization states; Nanopillar device; Shape anisotropy; Spin-transfer torque","Aluminum alloys; Cobalt alloys; Magnetization; Magnetocrystalline anisotropy; Nanopillars; Silicon alloys; Switching; Demagnetization fields; Geometric dimensions; Landau-Lifshitz-Gilbert equations; Magnetization switching; Micromagnetic simulations; Spin polarized currents; Spin transfer switching; Spin-valve nanopillars; Demagnetization","","","","","","","Grunberg P., Schreiber R., Pang Y., Brodsky M.B., Sowers H., Layered magnetic structures: evidence for antiferromagnetic coupling of Fe layers across Cr interlayers, J. Phys. Rev. Lett., 57, (1986); Baibich M.N., Broto J.M., Fert A., Nguyen van Dau F., Petroff F., Etienne P., Creuzet G., Friederich A., Chazelas J., Giant magnetoresistance of (001) Fe/ (001) Cr magnetic superlattices, J. Phys. Rev. Lett., 61, (1988); Ramaswamy B., Algarin J.M., Weinberg I.N., Chen Y.J., Krivorotov I.N., Katine J.A., Shapiro B., Waks E., Wireless current sensing by near field induction from a spin transfer torque nano-oscillator, J. App. Phys. Lett., 108, (2016); Nikolaev K., Anderson P., Kolbo P., Dimitrov D., Xue S., Peng X., Pokhil T., Cho H., Chen Y., Heusler alloy based current-perpendicular-to-the-plane giant magnetoresistance heads for high density magnetic recording, J. Appl. Phys., 103, (2008); Slonczewski J., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, (1996); Mangin S., Henry Y., Ravelosona D., Katine J.A., Fullerton E.E., Reducing the critical current for spin-transfer switching of perpendicularly magnetized nanomagnets, J. Appl. Phys. Lett., 94, (2009); Braganca P.M., Krivorotov I.N., Ozatay O., Garcia A.G.F., Emley N.C., Sankey J.C., Buhrman R.A., Reducing the critical current for short-pulse spin-transfer switching of nanomagnets, J. Appl. Phys. Lett., 87, (2005); Huai Y., Pakala M., Diao Z., Ding Y., Spin transfer switching current reduction in magnetic tunnel junction based dual spin filter structures, J. Appl. Phys. Lett., 87, (2005); Belrhazi H., El Hafidi M.Y., El Hafidi M., Effect of thermal fluctuation field on the magnetization switching by spin-transfer torque, J. Supercond. Nov. Magn, 33, (2020); Devolder T., Tahmasebi T., Eimer S., Hauet T., Andrieu S., Compositional dependence of the magnetic properties of epitaxial FeV/MgO thin films, J. Appl. Phys. Lett., 103, (2013); Sebastian T., Ohdaira Y., Kubota T., Pirro P., Bracher T., Vogt K., Serga A.A., Naganuma H., Oogane M., Ando Y., Hillebrands B., Low-damping spin-wave propagation in a micro-structured Co2Mn0.6Fe0.4Si Heusler waveguide, J Appl. Phys. Lett., 100, (2012); Gasi T., Nayak A.K., Winterlik J., Ksenofontov V., Adler P., Nicklas M., Felser C., Exchange-spring like magnetic behavior of the tetragonal Heusler compound Mn2FeGa as a candidate for spin-transfer torque, J. Appl. Phys. Lett., 102, (2013); Zhang J., Phung T., Pushp A., Ferrante Y., Jeong J., Rettner C., Hughes B.P., Yang S., Jiang Y., Parkin S.S.P., Bias dependence of spin transfer torque in Co2MnSi Heusler alloy based magnetic tunnel junctions, J. Appl. Phys. Lett., 110, (2017); Furubayashi T., Kodama K., Sukegawa H., Takahashi Y.K., Inomata K., Hono K., Current-perpendicular-to-plane giant magnetoresistance in spin-valve structures using epitaxial Co2FeAl0.5Si0.5/Ag/Co2FeAl0.5Si0.5 trilayers, J Appl. Phys. Lett., 93, (2008); Aoshima K., Funabashi N., Machida K., Miyamoto Y., Kuga K., Kawamura N., Current induced magnetization reversal in spin valves with Heusler alloys, J. Magn. Magn. Mater., 310, (2007); Lehndorff R., Buchmeier M., Bupsilonrgler D.E., Kakay A., Hertel R., Schneider C.M., Asymmetric spin-transfer torque in single-crystalline Fe ∕ Ag ∕ Fe nanopillars, J. Phys. Rev. B, 76, (2007); Sukegawa H., Kasai S., Furubayashi T., Mitani S., Inomata K., Spin-transfer switching in an epitaxial spin-valve nanopillar with a full-Heusler Co2FeAl0.5Si0.5 alloy, J Appl. Phys. Lett., 96, (2010); Berger L., Current-induced oscillations of a Bloch wall in magnetic thin films, J. Magn. Magn. Mater., 162, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, J. Phys. Rev. Lett., 84, (2000); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Microwave oscillations of a nanomagnet driven by a spin-polarized current, J. 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Phys., 103, (2008); Finocchio G., Azzerboni B., Fuchs G.D., Buhrman R.A., Torres L., Micromagnetic modeling of magnetization switching driven by spin-polarized current in magnetic tunnel junctions, J. Appl. Phys., 101, (2007); Li Z., Zhang S., Thermally assisted magnetization reversal in the presence of a spin-transfer torque, J. Phys. Rev. B, 69, (2004); Belrhazi H., El Hafidi M.Y., El Hafidi M., Micromagnetic simulation of current-induced magnetization dynamics in a half-Heusler Co1.5Fe1.5Ge alloy spin-valve nanopillar, J. SN Appl. Sci., 1, (2019); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Waeyenberge B.V., The design and verification of MuMax3, J. AIP. Adv., 4, (2014)","M.E. Hafidi; Condensed Matter Physics Laboratory, Department of Physics, Faculty of Science Ben M'sik, Hassan II University of Casablanca, Casablanca, D. El Harty Av., B.P 7955, 20165, Morocco; email: mohamed.elhafidi@univh2c.ma","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85083745595" +"Mankovsky S.; Ebert H.","Mankovsky, Sergiy (9943952600); Ebert, Hubert (7103402443)","9943952600; 7103402443","First-principles calculation of the parameters used by atomistic magnetic simulations","2022","Electronic Structure","4","3","034004","","","","6","10.1088/2516-1075/ac89c3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85138441472&doi=10.1088%2f2516-1075%2fac89c3&partnerID=40&md5=10b0770f32eac148acdedec7d52e8e21","Department of Chemistry/Phys. Chemistry, LMU Munich, Butenandtstrasse 11, Munich, D-81377, Germany","Mankovsky S., Department of Chemistry/Phys. Chemistry, LMU Munich, Butenandtstrasse 11, Munich, D-81377, Germany; Ebert H., Department of Chemistry/Phys. Chemistry, LMU Munich, Butenandtstrasse 11, Munich, D-81377, Germany","While the ground state of magnetic materials is in general well described on the basis of spin density functional theory (SDFT), the theoretical description of finite-temperature and non-equilibrium properties require an extension beyond the standard SDFT. Time-dependent SDFT (TD-SDFT), which give for example access to dynamical properties are computationally very demanding and can currently be hardly applied to complex solids. Here we focus on the alternative approach based on the combination of a parameterized phenomenological spin Hamiltonian and SDFT-based electronic structure calculations, giving access to the dynamical and finite-temperature properties for example via spin-dynamics simulations using the Landau-Lifshitz-Gilbert (LLG) equation or Monte Carlo simulations. We present an overview on the various methods to calculate the parameters of the various phenomenological Hamiltonians with an emphasis on the KKR Green function method as one of the most flexible band structure methods giving access to practically all relevant parameters. Concerning these, it is crucial to account for the spin-orbit coupling (SOC) by performing relativistic SDFT-based calculations as it plays a key role for magnetic anisotropy and chiral exchange interactions represented by the DMI parameters in the spin Hamiltonian. This concerns also the Gilbert damping parameters characterizing magnetization dissipation in the LLG equation, chiral multispin interaction parameters of the extended Heisenberg Hamiltonian, as well as spin-lattice interaction parameters describing the interplay of spin and lattice dynamics processes, for which an efficient computational scheme has been developed recently by the present authors. © 2022 IOP Publishing Ltd.","exchange coupling; green function formalism; relativistic effects","Calculations; Computation theory; Density functional theory; Electronic structure; Exchange coupling; Ground state; Intelligent systems; Magnetic anisotropy; Magnetic materials; Magnetism; Monte Carlo methods; Spin dynamics; Finite temperatures; First principle calculations; Green function formalism; Greens function; Interaction parameters; Landau-Lifshitz-Gilbert equations; Relativistic effects; Spin density functional theory; Spin hamiltonian; Temperature properties; Hamiltonians","","","","","","","Engel E, Dreizler R M, Density Functional Theory—An Advanced Course, (2011); Krieger K, Dewhurst J K, Elliott P, Sharma S, Gross E K U, J. 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Matter, 34, (2022); Assmann M, Nowak U, J. Magn. Magn. Mater, 469, pp. 217-223217, (2019); Hellsvik J, Thonig D, Modin K, Iusan D, Bergman A, Eriksson O, Bergqvist L, Delin A, Phys. Rev. B, 99, (2019); Sadhukhan B, Bergman A, Kvashnin Y O, Hellsvik J, Delin A, Phys. Rev. B, 105, (2022); Mankovsky S, Polesya S, Lange H, Weissenhofer M, Nowak U, Ebert H, Phys. Rev. Lett, 129, (2022); Schoen M A W, Lucassen J, Nembach H T, Koopmans B, Silva T J, Back C H, Shaw J M, Phys. Rev. B, 95, (2017); Fahnle M, Illg C, J. Phys.: Condens. Matter, 23, (2011); Jeppson S, Kukreja R, APL Mater, 9, (2021)","H. Ebert; Department of Chemistry/Phys. Chemistry, LMU Munich, Munich, Butenandtstrasse 11, D-81377, Germany; email: Hubert.Ebert@cup.uni-muenchen.de","","Institute of Physics","","","","","","25161075","","","","English","Electron. struct.","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85138441472" +"Greco A.F.G.; Rossi J.O.; Barroso J.J.; Yamasaki F.S.; Teixeira A.F.; Rangel E.G.L.; Neto L.P.S.; Schamiloglu E.","Greco, Ana F. G. (57196488042); Rossi, José O. (7202397572); Barroso, Joaquim J. (7103318266); Yamasaki, Fernanda S. (49561878200); Teixeira, André F. (57298275800); Rangel, Elizete G. L. (56012810200); Neto, Lauro P. S. (54791516800); Schamiloglu, Edl (7006390232)","57196488042; 7202397572; 7103318266; 49561878200; 57298275800; 56012810200; 54791516800; 7006390232","Analysis of the sharpening effect in gyromagnetic nonlinear transmission lines using the unidimensional form of the Landau-Lifshitz-Gilbert equation","2022","Review of Scientific Instruments","93","6","065101","","","","4","10.1063/5.0087452","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85131569983&doi=10.1063%2f5.0087452&partnerID=40&md5=bdb9ba479b11a66b26d5189d5b910f98","National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Federal University of São Paulo (UNIFESP), SP, São José dos Campos, 12247-014, Brazil; University of New Mexico (UNM), Albuquerque, 87131, NM, United States","Greco A.F.G., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Rossi J.O., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Barroso J.J., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Yamasaki F.S., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Teixeira A.F., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Rangel E.G.L., National Institute for Space Research (INPE), SP, São José dos Campos, 12227-010, Brazil; Neto L.P.S., Federal University of São Paulo (UNIFESP), SP, São José dos Campos, 12247-014, Brazil; Schamiloglu E., University of New Mexico (UNM), Albuquerque, 87131, NM, United States","Continuous nonlinear transmission lines (NLTLs), also known as gyromagnetic lines, consist of ferrite-based magnetic cores biased by an external magnetic field. Over the past years, many analytical and experimental studies have predicted the rise time reduction of the input pulse to the range of a few nanoseconds or even hundreds of ps experimentally observed in such gyromagnetic lines. This effect, known as pulse sharpening, is investigated in this paper built on a model based on a periodic structure of inductive-capacitive cells in series with magnetization-driven voltage sources expressed by the one-dimensional form (1D) of the Landau-Lifshitz-Gilbert (LLG) gyromagnetic equation. We explore the model through parametric study under various input-pulse parameters to understand the physics behind the ferrimagnetic material responses. Moreover, the numerical results obtained from computational simulations using Mathematica (v. 12.1) show how the line parameters (input voltage, damping constant, saturation magnetization, and length) affect the sharpening effect, which is quantified by the switching time. Our results on ferrite-loaded coaxial lines have confirmed many results found in the literature. We validated with a good agreement the proposed model with the result obtained by Dolan in 1993 using the same 1D form of the LLG equation, thus showing that the model proposed here is suitable to quantify the sharpening effect produced by a gyromagnetic NLTL. © 2022 Author(s).","","Ferrite; Nonlinear equations; Saturation magnetization; External magnetic field; Input pulse; Landau-Lifshitz-Gilbert equations; Model-based OPC; Nonlinear transmission lines; Pulse sharpening; Risetimes; Sharpening effect; Time reduction; Voltage source; Electric lines","","","","","SOARD; Air Force Office of Scientific Research, AFOSR; U.S. Air Force, USAF, (FA9550-18-1-0111, FA9550-19-1-0225); Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP, (2018/26086-2); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES, (88887.360820/2019-00, 88887.492309/2020-00); Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, (306540/2019-3)","The authors would like to thank the National Institute for Space Research—INPE and the Associated Plasma Laboratory—LABAP for providing the facilities for this research. This work was supported, in part, by CAPES (Grant Nos. 88887.492309/2020-00 and 88887.360820/2019-00), CNPq (Grant No. 306540/2019-3), FAPESP (Grant No. 2018/26086-2), and SOARD/AFSOR–USAF (Grants No. FA9550-18-1-0111 and FA9550-19-1-0225).","Landauer R., Shock waves in nonlinear transmission lines and their effect on parametric amplification, IBM J. Res. Dev., 4, pp. 391-401, (1960); Katayev I.G., Electromagnetic Shock Waves, (1966); Freeman R.H., Karbowiak A.E., An investigation of nonlinear transmission lines and shock waves, J. Phys. D: Appl. Phys., 10, (1977); Seddon N., Thornton E., A high-voltage, short-risetime pulse generator based on a ferrite pulse sharpener, Rev. Sci. Instrum., 59, pp. 2497-2498, (1988); Pouladian-Kari R., Shapland A.J., Benson T.M., Development of ferrite line pulse sharpeners for repetitive high-power applications, IEE Proceedings H (Microwaves, Antennas and Propagation), pp. 504-512, (1991); Benson T.M., Pouladian-Kari R., Shapland A.J., Novel operation of ferrite loaded coaxial lines for pulse sharpening applications, Electron. Lett., 27, pp. 861-863, (1991); Baker R.J., Hodder D.J., Johnson B.P., Et al., Generation of kilovolt-subnanosecond pulses using a nonlinear transmission line, Meas. Sci. Technol., 4, (1993); Branch G., Smith P.W., Fast-rise-time electromagnetic shock waves in nonlinear ceramic dielectrics, J. Phys. D: Appl. Phys., 29, (1996); Dolan J.E., Bolton H.R., Shapland A.J., Development of 60 ps rise-time ferrite-loaded coaxial line, Electron. Lett., 33, pp. 2049-2050, (1997); Rossi J.O., Yamasaki F.S., Barroso J.J., Et al., RF generation using a compact bench gyromagnetic line, Rev. Sci. Instrum., 93, (2022); Greco A.F.G., Rossi J.O., Barroso J.J., Et al., Numerical simulation of a gyromagnetic NLTL using an LC discrete line model, IEEE International Conference on Plasma Science (ICOPS) (IEEE), (2021); Dolan J.E., Simulation of ferrite-loaded coaxial lines, Electron. Lett., 29, pp. 762-763, (1993); Wolfram Research, Inc., Mathematica, Version 12.1, (2020); Dolan J.E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, J. Phys. D: Appl. Phys., 32, (1999); Tie W., Meng C., Zhao C., Lu X., Et al., Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application, Plasma Sci. Technol., 21, (2019); Dolan J.E., Effect of transient demagnetisation fields on coherent magnetic switching in ferrites, IEE Proc.-A: Sci., Meas. Technol., 140, pp. 294-298, (1993); Vasellar A., Experimentation and Modeling of Pulse Sharpening and Gyromagnetic Precession Within A Nonlinear Transmission Line, (2011); Gyorgy E.M., Rotational model of flux reversal in square loop ferrites, J. Appl. Phys., 28, pp. 1011-1015, (1957); Perks R.M., Dolan J.E., Modelling electromagnetic shock lines using finite difference time-domain (FDTD) and transmission line matrix (TLM)-type models, IEE Symposium on Pulsed Power'99 (Digest No. 1999/030) (IET), pp. 271-274, (1999); Weiner M., Silber L., Pulse sharpening effects in ferrites, IEEE Trans. Magn., 17, pp. 1472-1477, (1981); Furuya S., Matsumoto H., Fukuda H., Et al., Simulation of nonlinear coaxial line using ferrite beads, Jpn. J. Appl. Phys., 41, (2002); Huang L., Meng J., Zhu D., Yuan Y., Field-line coupling method for the simulation of gyromagnetic nonlinear transmission line based on the Maxwell-LLG system, IEEE Trans. Plasma Sci., 48, pp. 3847-3853, (2020); Dolan J.E., Bolton H.R., Shock front development in ferrite-loaded coaxial lines with axial bias, IEE Proc.-A: Sci., Meas. Technol., 147, pp. 237-242, (2000); Cui Y., Meng J., Huang L., Et al., Operation analysis of the wideband high-power microwave sources based on the gyromagnetic nonlinear transmission lines, Rev. Sci. Instrum., 92, (2021); Reale D.V., Parson J.M., Neuber A.A., Dickens J.C., Mankowski J.J., Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources, Rev. Sci. Instrum., 87, 3, (2016)","J.O. Rossi; National Institute for Space Research (INPE), São José dos Campos, SP, 12227-010, Brazil; email: jose.rossi@inpe.br","","American Institute of Physics Inc.","","","","","","00346748","","RSINA","35777999","English","Rev. Sci. Instrum.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85131569983" +"Li T.; Shi H.; Jin X.; Xue D.","Li, Tong (57224175656); Shi, Huigang (7402623170); Jin, Xiaowei (57224169092); Xue, Desheng (55447216200)","57224175656; 7402623170; 57224169092; 55447216200","High susceptibility of soft magnetic composites above MHz range","2021","Journal of Magnetism and Magnetic Materials","536","","168122","","","","3","10.1016/j.jmmm.2021.168122","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85107132976&doi=10.1016%2fj.jmmm.2021.168122&partnerID=40&md5=209bf3fbd26c98cb8f67ed871e578f46","Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China","Li T., Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; Shi H., Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; Jin X., Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; Xue D., Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China","We present a susceptibility model of bi-anisotropy soft magnetic composites (BSMCs) consisted of bi-anisotropy single-domain particle (BSDP) with a unified anisotropy which is a both polar and azimuthal angles related bi-anisotropy. We find that the product of initial susceptibility and resonance frequency in the BSDP is beyond Snoek's law. We derive the susceptibility of BSMCs further based on that of BSDP and find it is related to the orientations of both magnetization in static state and easy magnetization plane. More importantly, the maximum susceptibility of BSMCs is the same as that of a BSDP when the magnetizations in static state of BSDPs are oriented in one direction or plane. Our model provides an approach to improve the susceptibility of BSMCs. © 2021","Anisotropy; LLG equation; MHz; Soft magnetic composites; Susceptibility","","","","","","PCSIRT, (IRT-16R35); National Natural Science Foundation of China, NSFC, (11674143, 91963201); Higher Education Discipline Innovation Project, (B20063)","This work was supported by the NSFC (Grant Nos. 91963201 , and 11674143 ), PCSIRT (Grant No. IRT-16R35) and the 111 Project under Grant No. B20063. ","Barrett W.F., Brown W., Hadfield R.A., Researches on the electrical conductivity and magnetic properties of upwards of one hundred different alloys of iron, J. Inst Electr. Eng., 31, (1902); Elmen G.W., (1917); Duwez P., Lin S.C.H., Amorphous ferromagnetic phase in iron-carbon-phosphorus alloys, J. Appl. Phys., 38, (1967); van Wonterghem J., Morup S., Koch C.J.W., Charles S.W., Wells S., Nature (London), 322, (1986); Perigo E.A., Weidenfeller B., Kollar P., Fuzer J., Past, present, and future of soft magnetic composites, Appl. Phys. Rev., 5, (2018); Snoek J.L., Non-metallic magnetic material for high frequencies, Philips Tech. Rev., 8, (1946); Smit J., Wijn H.; Assawaworrarit S., Yu X., Fan S., Nature (London), 546, (2017); Siergiej R., Clarke R., Sriram S., Agarwal A., Bojko R., Morse A., Balakrishna V., MacMillan M., Burk A., Brandt C., Advances in sic materials and devices: an industrial point of view, Mater. Sci. Eng. 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Phys., 97, (2005); Han R., Qiao L., Wang T., Li F.S., Microwave complex permeability of planar anisotropy carbonyliron particles, J. Alloy. Compd., 509, (2011); Chi X., Yi H.B., Zuo W., Qiao L., Wang T., Li F., Complex permeability and microwave absorption properties of Y2Fe17micropowders with planar anisotropy, J. Phys. D, 44, (2011); Liu X., Or S.W., Leung C.M., Ho S.L., (2013); Song H., Tan M., Walker T.W., Jander A., Dhagat P., Planar alignment of magnetic microdisks in composites using rotating fields, IEEE Trans. Magn., 51, (2015); Yang W.F., Qiao L., Wei J.Q., Zhang Z.Q., Wang T., Li F.S., Microwave permeability of flake-shaped fecunbsib particle composite with rotational orientation, J. Appl. Phys., 107, (2010); Weidenfeller B., Anhalt M., Riehemann W., Variation of magnetic properties of composites filled with soft magnetic fecov particles by particle alignment in a magnetic field, J. Magn. Magn. Mater., 320, 14, pp. e362-e365, (2008); Song N.N., Gu S.Z., Zhou J., Xia W.X., Zhang P.P., Gul Q., Wang W., Yang H.T., Cheng Z.H., Achieving a high cutting-off frequency in the oriented CoFe2O4 nanocubes, Appl. Phys. Lett., 111, (2017); Zheng Y.Y., Wang Y.G., Xia G.T., Amorphous soft magnetic composite-cores with various orientations of the powder-flakes, J. Magn. Magn. Mater., 396, (2015)","H. Shi; Key Lab for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, China; email: shihuig@lzu.edu.cn","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85107132976" +"Wang W.; Du A.","Wang, Wang (57211349477); Du, An (7006264005)","57211349477; 7006264005","Simulation of the Faraday effect for the core–shell magnetic nanowire","2020","Journal of Magnetism and Magnetic Materials","511","","166591","","","","4","10.1016/j.jmmm.2020.166591","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85085220240&doi=10.1016%2fj.jmmm.2020.166591&partnerID=40&md5=3dc366e9d06cef35c864f899150e0bda","College of Science, Northeastern University, Shenyang, 110819, China","Wang W., College of Science, Northeastern University, Shenyang, 110819, China; Du A., College of Science, Northeastern University, Shenyang, 110819, China","In this paper, the core–shell magnetic nanowire was described by classical Heisenberg model with single-ion anisotropy and its Faraday effect was simulated by means of Landau–Lifshitz–Gilbert (LLG) equation. The results show that the resonance behavior of the nanowire appears in the circularly polarized microwave field. When the microwave frequency is higher than the resonance frequency of the nanowire, there is obvious Faraday effect in the nanowire, and the rotation angle for different frequencies is almost a constant value, and the value decreases as the temperature increases. In a microwave field with fixed frequency, the Faraday rotation angle changes with the internal magnetic structure of the nanowire, and shows a trend consistent with the magnetization curve. Therefore, we can regulate the Faraday effect of the nanowire by changing their magnetic structure or applying external magnetic field. © 2020 Elsevier B.V.","Core–shell magnetic nanowire; Faraday effect; Gilbert(LLG) equation; Landau; Lifshitz","Faraday effect; Magnetic structure; Magnetization; Circularly polarized microwaves; Classical Heisenberg model; External magnetic field; Faraday rotation angle; Magnetization curves; Resonance frequencies; Single ion anisotropy; Temperature increase; Nanowires","","","","","","","Liao S.B., Ferromagnetism, (1988); Wei W.G., Liu G.Q., Solid State Commun., 135, pp. 729-734, (2005); Kitaia T., Abeb S., Yoshidab H., Kawaec T., Kawazoeb Y., Kanekob T., J. Magn. Magn. Mater., 310, pp. e583-e585, (2007); Gao C.X., Farshchi R., Roder C., Dogan P., Brandt O., Phys. Rev. B, 83, (2011); Brauns M., Ridderbos J., Li A., Bakkers E.P.A.M., Zwanenburg F.A., Phys. Rev. B, 93, (2016); Benitez M.J., Petracic O., Salabas E.L., Radu F., Tuysuz H., Schuth F., Zabel H., Phys. Rev. Lett., 101, (2008); Bouhou S., Essaoudi I., Ainane A., Saber M., Dujardin F., de J., Miguel, J. Magn. Magn. Mater., 324, pp. 2434-2441, (2012); Magoussi H., Zaim A., Kerouad M., Solid State Commun., 200, pp. 32-41, (2014); XianYu Z.N., Du A., J. Appl. Phys., 124, (2018); Lv D., Jiang W., Ma Y., Gao Z.Y., Wang F., Physica E: Low-dimensional Systems and Nanostructure, 106, pp. 101-113, (2019); Okano1 G., Nozaki Y., Phys. Rev. B, 97, (2018); Xu F., Zhang X.Y., Phuoc N.N., Ma Y.G., Ong C.K., J. Appl. Phys, 105, (2009); Choi M., Lee S., Kim J., Trans I.E.E.E., Magn., 53, (2017); Nakayama K.S., Chiba T., Tsukimoto S., Yokoyama Y., Shima T., Yabukami S., (2014); Alkadour B., Mercer J.I., Whitehead J.P., van Lierop J., Southern B.W., Phys. Rev. B, 93, (2016); Chubykalo-Fesenko O., Nowak U., Chantrell R.W., Garanin D., Phys. Rev. B, 74, (2006); Picco M., Ritort F., Phys. Rev. B, 71, (2005); Wang W., Du A., Mater. Res. Express, 6, (2019); Wang D.W., Weerasinghe J., Bellaiche L., Phys. Rev. Lett., 109, (2012)","","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85085220240" +"Goncharov A.V.; Bashir A.; Van Der Heijden P.","Goncharov, Alexander V. (56394838800); Bashir, Asif (57218543705); Van Der Heijden, Paul (7004309878)","56394838800; 57218543705; 7004309878","Stability of Spin-Torque Oscillators with Dual Free Layers","2020","IEEE Transactions on Magnetics","56","8","9102236","","","","1","10.1109/TMAG.2020.2998057","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85089529129&doi=10.1109%2fTMAG.2020.2998057&partnerID=40&md5=232cc629b3fc0dab470d3d002b43cf9c","Western Digital Corporation, San Jose, CA, United States","Goncharov A.V., Western Digital Corporation, San Jose, CA, United States; Bashir A., Western Digital Corporation, San Jose, CA, United States; Van Der Heijden P., Western Digital Corporation, San Jose, CA, United States","A system of differential equations describing the stability of a spin-torque oscillator (STO) with two free layers is introduced. The system is derived from the Landau-Lifshitz-Gilbert (LLG) equation for two freely rotating magnetic moments interacting via spin-torque. In the case of two free magnetic layers, the magnetization of each layer can precess at its own frequency, which is directly proportional to the local effective field in the layer. The spin-torque depends on the relative angle between two layers. Therefore, if the magnetization in two magnetic layers rotates with different frequencies, the spin-torque will vary in time. This can lead to instabilities of the precession angle in both the layers. When two layers oscillate at equal frequencies, instabilities due to spin-torque variations are eliminated. The requirement for the synchronization leads to a system of three differential equations for three unknowns. The stable oscillation orbits for each layer are obtained by finding fixed point solutions of the system. The results were confirmed using finite-element method (FEM) micromagnetic simulations. © 1965-2012 IEEE.","Micromagnetics; microwave-assisted magnetic recording (MAMR); spin-torque oscillator (STO)","Differential equations; Magnetic materials; Magnetic moments; Magnetization; Different frequency; Landau-Lifshitz-Gilbert equations; Local effective fields; Micromagnetic simulations; Spin-torque oscillator (STO); Spin-torque oscillators; Stable oscillations; System of differential equations; Torque","","","","","","","Zhu J.-G., Zhu X., Tang Y., Microwave assisted magnetic recording, IEEE Trans. Magn., 44, 1, pp. 125-131, (2008); Igarashi M., Suzuki Y., Miyamoto H., Maruyama Y., Shiroishi Y., Effect of elliptical high-frequency field on microwave-assisted magnetic switching, IEEE Trans. Magn., 45, 10, pp. 3711-3713, (2009); Igarashi M., Suzuki Y., Sato Y., Oscillation feature of planar spin-torque oscillator for microwave-assisted magnetic recording, IEEE Trans. Magn., 46, 10, pp. 3738-3741, (2010); Yoshida K., Yokoe M., Ishikawa Y., Kanai Y., Spin-torque oscillator with negative magnetic anisotropy materials for MAMR, IEEE Trans. Magn., 46, 6, pp. 2466-2469, (2010); Carey M.J., Et al., Co2MnGe-based current-perpendicular-to-the-plane giant-magnetoresistance spin-valve sensors for recording head applications, J. Appl. Phys., 109, 9, (2011); Sepehri-Amin H., Et al., Design of spin-injection-layer in all-inplane spin-torque-oscillator for microwave assisted magnetic recording, J. Magn. Magn. Mater., 476, pp. 361-370, (2019); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, Condens. Matter, 62, 1, (2000); Yan S., Sun Z., Bazaliy Y.B., Modification of the Stoner-Wohlfarth astroid by a spin-polarized current: An exact solution, Phys. Rev. B, Condens. Matter, 88, 5, (2013); Serpico C., Mayergoyz I.D., Bertotti G., Analytical solutions of Landau-Lifshitz equation for precessional switching, J. Appl. Phys., 93, 10, pp. 6909-6911, (2003); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., D'Aquino M., Bonin R., Magnetization switching and microwave oscillations in nanomagnets driven by spin-polarized currents, Phys. Rev. Lett., 94, 12, pp. 1272061-1272064, (2005); Taniguchi T., Synchronized, periodic, and chaotic dynamics in spin-torque oscillator with two free layers, J. Magn. Magn. Mater., 483, pp. 281-292, (2019); Fukushima H., Nakatani Y., Hayashi N., Volume average demagnetizing tensor of rectangular prisms, IEEE Trans. Magn., 34, 1, pp. 193-198, (1998); Liapunov A.M., Stability of Motion, (1966)","A.V. Goncharov; Western Digital Corporation, San Jose, United States; email: alexander.goncharov@wdc.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85089529129" +"Ahirwar S.; Pramanik T.","Ahirwar, Sonalie (57226533307); Pramanik, Tanmoy (55938287000)","57226533307; 55938287000","A simulation study of stand-by and active write mode magnetic immunity of perpendicular spin-transfer-torque random-access memory","2022","2022 IEEE International Conference on Emerging Electronics, ICEE 2022","","","","","","","0","10.1109/ICEE56203.2022.10117969","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85160565878&doi=10.1109%2fICEE56203.2022.10117969&partnerID=40&md5=0c8a7bc94b8e01a705799aca35d895d8","Indian Institute of Technology Roorkee, Department of Electronics and Communication Engineering, Roorkee, India","Ahirwar S., Indian Institute of Technology Roorkee, Department of Electronics and Communication Engineering, Roorkee, India; Pramanik T., Indian Institute of Technology Roorkee, Department of Electronics and Communication Engineering, Roorkee, India","Magnetic immunity is an important reliability metric for spin-transfer-torque random-access memory (STT-RAM). The presence of an external magnetic field may cause retention fails in stand-by mode or switching fails during the write operation. Specifically, active write mode magnetic immunity has not been well explored although it was reported to be the limiter in deciding the magnetic immunity metrics. Here, we present a simulation study of stand-by bit error rates (BER) and write error rates (WER) under the influence of external magnetic field perturbation. Results show that the effect of the external magnetic field is more pronounced when it is applied along a direction non-collinear to the easy axis of the magnet. Variation in the stand-by BER is found to follow the Stoner-Wohlfarth model. It is also observed that the active write mode BER may increase by orders of magnitude for specific directions of applied fields depending on the applied write current and magnetic field strength. The variation in WER is explained by the formation of additional zero-torque 'stagnation points' on the magnetization unit sphere. The results show the need for careful characterization of both the stand-by mode and the active write mode while measuring the magnetic immunity of the STT-RAM cell. © 2022 IEEE.","LLG equation; stagnation points; STT-RAM; write error rate","Errors; Magnetic fields; Random access storage; Bit-error rate; Error rate; External magnetic field; LLG equation; Magnetic immunity; Random access memory; Spin transfer torque; Spin-transfer-torque random-access memory; Stagnation points; Write error rate; Bit error rate","","","","","Science and Engineering Research Board, SERB","This work has been supported by the Science and Engineering Research Board, Govt. of India via Grant no. SRG/2021/000377.","Golonzka O., Et al., MRAM as Embedded Non-Volatile Memory Solution for 22FFL FinFET Technology, 2018 IEEE International Electron Devices Meeting (IEDM), pp. 1811-1814, (2018); Naik V.B., Et al., Manufacturable 22nm FD-SOI Embedded MRAM Technology for Industrial-grade MCU and IOT Applications, 2019 IEEE International Electron Devices Meeting (IEDM), pp. 231-234, (2019); Lee K., Et al., 22-nm FD-SOI Embedded MRAM with Full Solder Reflow Compatibility and Enhanced Magnetic Immunity, 2018 IEEE Symposium on VLSI Technology, pp. 183-184, (2018); Gallagher W.J., Et al., 22nm STT-MRAM for Reflow and Automotive Uses with High Yield, Reliability, and Magnetic Immunity and with Performance and Shielding Options, 2019 IEEE International Electron Devices Meeting (IEDM), pp. 271-274, (2019); Alzate J.G., Et al., 2 MB Array-Level Demonstration of STT-MRAM Process and Performance Towards L4 Cache Applications, 2019 IEEE International Electron Devices Meeting (IEDM), pp. 241-244, (2019); Wei L., Et al., 13. 3 A 7Mb STT-MRAM in 22FFL FinFET Technology with 4ns Read Sensing Time at 0. 9V Using Write-Verify-Write Scheme and Offset-Cancellation Sensing Technique, 2019 IEEE International Solid-State Circuits Conference-(ISSCC), pp. 214-216, (2019); Ji Y., Et al., Reliability of 8Mbit Embedded-STT-MRAM in 28nm FDSOI Technology, 2019 IEEE International Reliability Physics Symposium (IRPS), pp. 1-3, (2019); Lee T.Y., Et al., Magnetic Immunity Guideline for Embedded MRAM Reliability to Realize Mass Production, 2020 IEEE International Reliability Physics Symposium (IRPS), pp. 1-4, (2020); Xie Y., Behin-Aein B., Ghosh A.W., Fokker-Planck Study of Parameter Dependence on Write Error Slope in Spin-Torque Switching, IEEE Transactions on Electron Devices, 64, 1, pp. 319-324, (2017); Butler W.H., Et al., Switching Distributions for Perpendicular Spin-Torque Devices Within the Macrospin Approximation, IEEE Transactions on Magnetics, 48, 12, pp. 4684-4700, (2012); Geuzaine C., Remacle J.-F., Gmsh: A three-dimensional finite element mesh generator with built-in pre-and post-processing facilities, International Journal for Numerical Methods in Engineering, 79, 11, pp. 1309-1331, (2009); Intel oneAPI Math Kernel Library, (2022); Xie Y., Multiscale approach to spintronics-from nanomagnet to tomological excitations, (2019); Roy U., Pramanik T., Register L.F., Banerjee S.K., Write Error Rate of Spin-Transfer-Torque Random Access Memory Including Micromagnetic Effects Using Rare Event Enhancement, IEEE Transactions on Magnetics, 52, 10, pp. 1-6, (2016); Pramanik T., Roy U., Jadaun P., Register L.F., Banerjee S.K., Write error rates of in-plane spin-transfer-torque random access memory calculated from rare-event enhanced micromagnetic simulations, Journal of Magnetism and Magnetic Materials, 467, pp. 96-107, (2018); Nowak J.J., Robertazzi R.P., Sun J.Z., Hu G., Park J.-H., Lee J., Annunziata A.J., Lauer G.P., Kothandaraman R., O'Sullivan E.J., Trouilloud P.L., Kim Y., Worledge D.C., Kumar Miriyala V.P., Fong X., Liang G., Dependence of Voltage and Size on Write Error Rates in Spin-Transfer Torque Magnetic Random-Access Memory, IEEE Magnetics Letters, 7, pp. 1-4, (2016); Kumar Miriyala V.P., Fong X., Liang G., FANTASI: A novel devices-to-circuits simulation framework for fast estimation of write error rates in spintronics, 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), pp. 53-57, (2018); Bouquin P., Rao S., Sankar Kar G., Devolder T., Size dependence of spin-torque switching in perpendicular magnetic tunnel junctions, Appl. Phys. Lett., 113, (2018); Heindl R., Rippard W.H., Russek S.E., Kos A.B., Physical limitations to efficient high-speed spin-torque switching in magnetic tunnel junction, Physical Review B, 83, 5, (2011)","","","Institute of Electrical and Electronics Engineers Inc.","","2022 IEEE International Conference on Emerging Electronics, ICEE 2022","11 December 2022 through 14 December 2022","Bangalore","188690","","978-166549185-3","","","English","IEEE Int. Conf. Emerg. Electron., ICEE","Conference paper","Final","","Scopus","2-s2.0-85160565878" +"Tandon P.; Sahu R.; Mishra A.C.","Tandon, Prerit (57781634200); Sahu, Rahul (57660469700); Mishra, Amaresh Chandra (36667100300)","57781634200; 57660469700; 36667100300","Giant magnetoimpedance effect in electrodeposited CoNiFe/Cu composite wire: Experimental study and analytical modelling","2022","Physica B: Condensed Matter","642","","414131","","","","6","10.1016/j.physb.2022.414131","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85133474513&doi=10.1016%2fj.physb.2022.414131&partnerID=40&md5=c46baa73db826f82802358ea8256f4c0","Natural Sciences, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, 482005, India","Tandon P., Natural Sciences, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, 482005, India; Sahu R., Natural Sciences, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, 482005, India; Mishra A.C., Natural Sciences, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, 482005, India","Study of giant magnetoimpedance effect (GMI) in electrodeposited CoNiFe/Cu composite wire is reported in the intermediate frequency region (10 kHz–10 MHz). The room temperature M–H curve of the sample reveals that the magnetic softness is independent of the film thickness(t). The changes in GMI value is attributed to the geometric effect caused by change of film thickness. To justify this claim, a hybrid model for circumferential permeability is proposed by combining the effect of domain wall motion(μdw), spin rotation (μrot) and local dispersion of anisotropy. The spectra of circumferential permeability is modelled with domain wall relaxation with continuous distribution of relaxation times. The spin rotation part of circumferential permeability is formulated using linearized Landau–Lifshitz–Gilbert (LLG) equation with Bloch–Bloembergen damping term and dispersion of anisotropy field. The proposed model is able to reproduce all the experimental results using single set of material parameters. © 2022 Elsevier B.V.","Anisotropy dispersion; Bloch–Bloembergen damping; Domain wall motion; Electrodeposition; Relaxation; Spin rotation","Anisotropy; Dispersions; Domain walls; Electrodeposition; Electrodes; Film thickness; Spin dynamics; Anisotropy dispersion; Bloch–bloembergen damping; Composite wires; Domain wall motion; Film-thickness; Frequency regions; Giant magneto impedance effect; Intermediate frequencies; Relaxation; Spin-rotations; Damping","","","","","Ministry of Education, India, MoE; Board of Research in Nuclear Sciences, BRNS, (BRNS YSRA PROJECT 59/20/03/2020-BRNS/59002)","Prerit Tandon and Rahul Sahu would like to thank Ministry of Human Resource Development (MHRD), New Delhi, India , for providing financial assistance for carrying out this work. The authors are thankful to Prof. V. Srinivas, Indian Institute of Technology, Madras for his valuable suggestions during the work. This work has been done with the financial support from Board of Research in Nuclear Sciences, Bombay, India (BRNS YSRA PROJECT 59/20/03/2020-BRNS/59002 ). All authors approved the version of the manuscript to be published.","Kalhor S., Ghanaatshoar M., Aliaskarisohi S., Magnetoimpedance and magnetooptical properties of electrodeposited NiFeMo ribbons, Appl. Phys. A, 124, (2018); Wang T., Zhou Y., Lei C., Luo J., Xie S., Pu H., Magnetic impedance biosensor: A review, Biosens. Bioelectron., (2017); Rifai D., Abdalla A.N., Ali K., Razali R., Giant magnetoresistance sensors: A review on structures and non-destructive eddy current testing applications, Sensors, 16, (2016); Li B., Kavaldzhiev M.N., Kosel J., Flexible magnetoimpedance sensor, J. Magn. Magn. Mater., 378, pp. 499-505, (2015); Kaviraj B., Ghatak S.K., Magnetic field and displacement sensor based on giant magneto-impedance effect, Mater. Manuf. Process., 21, pp. 271-274, (2006); Panina L.V., Mohri K., Magneto-impedance effect in amorphous wires, Appl. Phys. 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Alloys Compd., 541, pp. 215-221, (2012); Ghatak S., Influence of demagnetization effect on giant magneto-impedance of soft ferromagnetic metal, Solid State Commun., 150, pp. 1150-1153, (2010); Gromov A., Korenivski V., Electromagnetic analysis of layered magnetic/conductor structures, J. Phys. D: Appl. Phys., 33, pp. 773-779, (2000); Mishra A.C., Sahoo T., Srinivas V., Thakur A.K., Samantaray B., Ravi S., Large enhancement of giant magnetoimpedance property in electrodeposited NiFe/Cu wire with copper additive in plating bath, Solid State Commun., 151, pp. 1787-1790, (2011); Mishra A.C., Sahoo T., Srinivas V., Thakur A.K., Microstructure, magnetic, and magnetoimpedance properties of electrodeposited NiFe/Cu and CoNiFe/Cu wire: A study on influence of saccharin additive in plating bath, J. Appl. Phys., 109, (2011); Kammouni R.E., Chlenova A.A., Volchkov S.O., Kurlyandskaya G.V., Magnetic properties and magnetoimpedance of FeCoNi/CuBe electroplated tubes with different features of field-annealing induced magnetic anisotropy, J. Magn. Magn. Mater., 423, pp. 183-190, (2017); Phan M.H., Peng H.X., Giant magnetoimpedance materials:Fundamentals and applications, Prog. Mater. Sci., 53, pp. 323-420, (2008); Alekhina I., Kolesnikova V., Rodionov V., Andreev N., Panina L., Rodionova V., Perov N., An indirect method of micromagnetic structure estimation in microwires, Nanomaterials 2021, 11, pp. 1-16, (2021); Usov N., Antonov A., Granovsky A., Theory of giant magneto-impedance effect in composite amorphous wire, J. Magn. Magn. Mater., 171, pp. 64-68, (1997); Bavall L., Determination of coating thickness of a copper-plated steel wire by measurement of the internal wire impedance, IEEE Trans. Instrum. Meas., 47, pp. 1013-1019, (1998); Mishra A.C., Sahoo T., Thakur A.K., Srinivas V., Giant magnetoimpedance in electrodeposited CoNiFe/Cu wire: A study on thickness dependence, J. Alloys Compd., 480, pp. 771-776, (2009); Mishra A.C., Sahoo T., Srinivas V., Thakur A.K., Investigation of magnetoimpedance effect on electrodeposited NiFe/Cu wire using inductance spectroscopy, Physica B, 406, pp. 645-651, (2011); Jantaratana P., Sirisathitkul C., Effects of thickness and heat treatments on giant magnetoimpedance of electrodeposited cobalt on silver wires, IEEE Trans. Magn., 42, pp. 358-362, (2006); Seet H.L., Li X.P., Ning N., Ng W.C., Yi J.B., Effect of magnetic coating layer thickness on the magnetic properties of electrodeposited NiFe/Cu composite wires, IEEE Trans. Magn., 42, pp. 2784-2786, (2006); Valenzuela R., Montiel H., Gutierrez M.P., Betancourt I., Characterization of soft ferromagnetic materials by inductance spectroscopy and magnetoimpedance, J. Magn. Magn. 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Phys., 87, pp. 4822-4824, (2000); Kraus L., GMI modeling and material optimization, Sensors Actuators A, 106, pp. 187-194, (2003); Valenzuela R., Giant magnetoimpedance and inductance spectroscopy, J. Alloys Compd., 369, pp. 40-42, (2004); Usov N., Antonov A., Lagarkov A., Theory of giant magneto-impedance effect in amorphous wireswith different types of magnetic anisotropy, J. Magn. Magn. Mater., 185, pp. 159-173, (1998); Zhukova V., Blanco J.M., Ipatov M., Churyukanova M., Taskaev S., Zhukov A., Tailoring of magnetoimpedance effect and magnetic softness of Fe-rich glass-coated microwires by stress- annealing, Sci. Rep., 8, (2018); Leon P.C., Zhukova V., Ipatov M., Blanco J.M., Gonzalez J., Dominguez L., Churyukanova M., Zhukov A., High frequency giant magnetoimpedance effect of a stress-annealed Fe-rich glass-coated microwire, J. 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Lett., 107, (2011); Li W.H., Jin Z., Wen D.L., Zhang X.M., Qin M.H., Liu J.M., Ultrafast domain wall motion in ferrimagnets induced by magnetic anisotropy gradient, Phys. Rev. B, 101, (2020); Jin Z., Liu T.T., Li W.H., Zhang X.M., Hou Z.P., Chen D.Y., Fan Z., Zeng M., Lu X.B., Gao X.S., Qin M.H., Liu J.M., Dynamics of antiferromagnetic skyrmions in the absence or presence of pinning defects, Phys. Rev. B, 102, (2020); Kraus L., Theory of giant magneto-impedance in the planar conductor with uniaxial magnetic anisotropy, J. Magn. Magn. Mater., 195, pp. 764-778, (1999); Menard D., Yelon A., Theory of longitudinal magnetoimpedance in wires, J. Appl. Phys., 88, pp. 379-393, (2000); Correa M.A., Ferreira A., Souza A.L.R., Neto N.F.A., Motta F.V., Bomio M.R.D., Bohn F., Vaz F., Co2FeAl Heusler alloy onto amorphous TiO2 layer: Exploring the quasi-static and dynamic magnetic properties, J. Phys. Chem. Solids, 154, (2021); Cooper E.I., Bonhote C., Heidmann J., Hsu Y., Kern P., Lam J.W., Ramasubramanian M., Robertson N., Romankiw L.T., Xu H., Recent developments in high-moment electroplated materials for recording heads, IBM J. Res. Dev., 49, pp. 103-126, (2005); Lachowicz H.K., Garcia K.L., Kuzminski M., Zhukov A., Vazquez M., Skin-effect and circumferential permeability in micro-wiresutilized in GMI-sensors, Sens. Actuar. A, 119, pp. 384-389, (2005); Vasam S., Srinivas V., Microstructure and magnetoimpedance studies of NiFe films electrodeposited on ITO substrate: Experiments and simulations, J. Magn. Magn. Mater., 514, (2020)","A.C. Mishra; Natural Sciences, Indian Institute of Information Technology, Design & Manufacturing, Jabalpur, 482005, India; email: amresh@iiitdmj.ac.in","","Elsevier B.V.","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-85133474513" +"Islam M.T.; Akanda M.A.S.; Pikul M.A.J.; Wang X.","Islam, Md. Torikul (59157888400); Akanda, Md. Abdus Sami (58189990800); Pikul, Md. Abu Jafar (57221317240); Wang, Xiansi (58396230100)","59157888400; 58189990800; 57221317240; 58396230100","Fast magnetization reversal of a magnetic nanoparticle induced by cosine chirp microwave field pulse","2022","Journal of Physics Condensed Matter","34","10","105802","","","","4","10.1088/1361-648X/ac3f66","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85123390552&doi=10.1088%2f1361-648X%2fac3f66&partnerID=40&md5=444ac39312b378a3e63a79c0959156eb","Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; School of Physics and Electronics, Hunan University, Changsha, 410082, China","Islam M.T., Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Akanda M.A.S., Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Pikul M.A.J., Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; Wang X., School of Physics and Electronics, Hunan University, Changsha, 410082, China","We investigate the magnetization reversal of single-domain magnetic nanoparticle driven by the circularly polarized cosine chirp microwave pulse (CCMP). The numerical findings, based on the Landau-Lifshitz-Gilbert equation, reveal that the CCMP is by itself capable of driving fast and energy-efficient magnetization reversal. The microwave field amplitude and initial frequency required by a CCMP are much smaller than that of the linear down-chirp microwave pulse. This is achieved as the frequency change of the CCMP closely matches the frequency change of the magnetization precession which leads to an efficient stimulated microwave energy absorption (emission) by (from) the magnetic particle before (after) it crosses over the energy barrier. We further find that the enhancement of easy-plane shape anisotropy significantly reduces the required microwave amplitude and the initial frequency of CCMP. We also find that there is an optimal Gilbert damping for fast magnetization reversal. These findings may provide a pathway to realize the fast and low-cost memory device. © 2021 IOP Publishing Ltd.","cosine chirp pulse; LLG equation; magnetization reversal; shape anisotropy","Anisotropy; Chirp modulation; Energy efficiency; Microwaves; Chirp pulse; Cosine chirp pulse; Fast magnetization; Frequency changes; Initial frequency; LLG equation; Magnetization - reversal; Microwave field; Microwave pulse; Shape anisotropy; Magnetization reversal","","","","","","","Sun S, Murray C B, Weller D, Folks L, Moser A, Science, 287, pp. 1989-1992, (2000); Woods S I, Kirtley J R, Sun S, Koch R H, Phys. Rev. Lett, 87, (2001); Zitoun D, Respaud M, Fromen M C, Casanove M J, Lecante P, Amiens C, Chaudret B, Phys. Rev. Lett, 89, (2002); Hillebrands B, Ounadjela K, Spin Dynamics in Confined Magnetic Structures I & II, 83, (2003); Mangin S, Ravelosona D, Katine J A, Carey M J, Terris B D, Fullerton E E, Nat. Mater, 5, pp. 210-215, (2006); Hubert A, Schafer R, Magnetic Domains: The Analysis of Magnetic Microstructures, (1998); Sun Z Z, Wang X R, Phys. Rev. B, 71, (2005); Bertotti G, Serpico C, Mayergoyz I D, Phys. Rev. Lett, 86, (2001); Sun Z, Wang X, Phys. Rev. B, 73, (2006); Zhu J-G, Wang Y, IEEE Trans. Magn, 46, pp. 751-757, (2010); Slonczewski J C, Et al., J. Magn. Magn. Mater, 159, (1996); Berger L, Phys. Rev. B, 54, (1996); Tsoi M, Jansen A G M, Bass J, Chiang W-C, Seck M, Tsoi V, Wyder P, Phys. Rev. Lett, 80, (1998); Sun J Z, J. Magn. Magn. Mater, 202, pp. 157-162, (1999); Bazaliy Y B, Jones B A, Zhang S-C, Phys. Rev. B, 57, (1998); Katine J A, Albert F J, Buhrman R A, Myers E B, Ralph D C, Phys. Rev. Lett, 84, pp. 3149-3152, (2000); Waintal X, Myers E B, Brouwer P W, Ralph D C, Phys. Rev. B, 62, pp. 12317-12327, (2000); Sun J Z, Phys. Rev. B, 62, (2000); Sun J, Nature, 425, pp. 359-360, (2003); Stiles M D, Zangwill A, Phys. Rev. B, 66, (2002); Bazaliy Y B, Jones B, Zhang S C, Phys. Rev. B, 69, (2004); Koch R, Katine J, Sun J, Phys. Rev. Lett, 92, (2004); Li Z, Zhang S, Phys. Rev. B, 69, (2004); Wetzels W, Bauer G E W, Jouravlev O N, Phys. Rev. Lett, 96, (2006); Manchon A, Zhang S, Phys. Rev. B, 78, (2008); Mihai Miron I, Gaudin G, Auffret S, Rodmacq B, Schuhl A, Pizzini S, Vogel J, Gambardella P, Nat. Mater, 9, pp. 230-234, (2010); Miron I M, Et al., Nature, 476, pp. 189-193, (2011); Liu L, Pai C-F, Li Y, Tseng H W, Ralph D C, Buhrman R A, Science, 336, pp. 555-558, (2012); Denisov S I, Lyutyy T V, Hanggi P, Trohidou K N, Phys. Rev. B, 74, (2006); Okamoto S, Kikuchi N, Kitakami O, Appl. Phys. Lett, 93, (2008); Tanaka T, Otsuka Y, Furomoto Y, Matsuyama K, Nozaki Y, J. Appl. Phys, 113, (2013); Grollier J, Cros V, Jaffres H, Hamzic A, George J M, Faini G, Ben Youssef J, Le Gall H, Fert A, Phys. Rev. B, 67, (2003); Morise H, Nakamura S, Phys. Rev. B, 71, (2005); Taniguchi T, Imamura H, Phys. Rev. B, 78, (2008); Suzuki Y, Tulapurkar A A, Chappert C, Spin-injection phenomena and applications Nanomagnetism and Spintronics, pp. 93-153, (2009); Sun Z, Wang X, Phys. Rev. Lett, 97, (2006); Wang X, Sun Z, Phys. Rev. Lett, 98, (2007); Wang X R, Yan P, Lu J, He C, Europhys. Lett, 84, (2008); Thirion C, Wernsdorfer W, Mailly D, Nat. Mater, 2, pp. 524-527, (2003); Rivkin K, Ketterson J B, Appl. Phys. Lett, 89, (2006); Wang Z, Wu M, J. Appl. Phys, 105, (2009); Barros N, Rassam M, Jirari H, Kachkachi H, Phys. Rev. B, 83, (2011); Barros N, Rassam H, Kachkachi H, Phys. Rev. B, 88, (2013); Klughertz G, Hervieux P-A, Manfredi G, J. Phys. D: Appl. Phys, 47, (2014); Islam M T, Wang X S, Zhang Y, Wang X R, Phys. Rev. B, 97, (2018); Cai L, Garanin D A, Chudnovsky E M, Phys. Rev. B, 87, (2013); Cai L, Chudnovsky E M, Phys. Rev. B, 82, (2010); Dubowik J, Phys. Rev. B, 54, (1996); Aharoni A, J. Appl. Phys, 83, pp. 3432-3434, (1998); Gilbert T L, IEEE Trans. Magn, 40, pp. 3443-3449, (2004); Vansteenkiste A, Leliaert J, Dvornik M, Helsen M, Garcia-Sanchez F, Van Waeyenberge B, AIP Adv, 4, (2014); Hasegawa T, Kanatani S, Kazaana M, Takahashi K, Kumagai K, Hirao M, Ishio S, Sci. Rep, 7, (2017); Wang Z, Sun K, Tong W, Wu M, Liu M, Sun N X, Phys. Rev. B, 81, (2010); Chen Y P, Fan X, Lu Q, Xiao J Q, J. Appl. Phys, 110, (2011); Guo J, Jalil M B A, Tan S G, IEEE Trans. Magn, 43, pp. 2923-2925, (2007); Islam M T, Pikul M A J, Wang X S, J. Magn. Magn. Mater, 537, (2021)","M.T. Islam; Physics Discipline, Khulna University, Khulna, 9208, Bangladesh; email: torikul@phy.ku.ac.bd","","IOP Publishing Ltd","","","","","","09538984","","JCOME","34874303","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85123390552" +"Yuan J.-H.; Yang X.-K.; Zhang B.; Chen Y.-B.; Zhong J.; Wei B.; Song M.-X.; Cui H.-Q.","Yuan, Jia-Hui (57235074800); Yang, Xiao-Kuo (24777556700); Zhang, Bin (57199725653); Chen, Ya-Bo (57210175057); Zhong, Jun (57304518500); Wei, Bo (57203552828); Song, Ming-Xu (57216831494); Cui, Huan-Qing (56086034100)","57235074800; 24777556700; 57199725653; 57210175057; 57304518500; 57203552828; 57216831494; 56086034100","Activation function and computing performance of spin neuron driven by magnetic field and strain; [混合时钟驱动的自旋神经元器件激活特性和计算性能]","2021","Wuli Xuebao/Acta Physica Sinica","70","20","207502","","","","3","10.7498/aps.70.20210611","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85117601890&doi=10.7498%2faps.70.20210611&partnerID=40&md5=869d7939ac0477d8e8ebf037789e66f4","Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; College of Computer, National University of Defense, Changsha, 410005, China; Airforce Command College, Beijing, 100097, China","Yuan J.-H., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; Yang X.-K., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; Zhang B., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; Chen Y.-B., College of Computer, National University of Defense, Changsha, 410005, China; Zhong J., Airforce Command College, Beijing, 100097, China; Wei B., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; Song M.-X., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; Cui H.-Q., Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China","The spin neuron is an emerging artificial neural device which has many advantages such as ultra-low power consumption, strong nonlinearity, and high integration. Besides, it has ability to remember and calculate at the same time. So it is seen as a suitable and excellent candidate for the new generation of neural network. In this paper, a spin neuron driven by magnetic field and strain is proposed. The micromagnetic model of the device is realized by using the OOMMF micromagnetic simulation software, and the numerical model of the device is also established by using the LLG equation. More importantly, a three-layer neural network is composed of spin neurons constructed respectively using three materials (Terfenol-D, FeGa, Ni). It is used to study the activation functions and the ability to recognize the MNIST handwritten datasets.c Results show that the spin neuron can successfully achieve the random magnetization switching to simulate the activation behavior of the biological neuron. Moreover, the results show that if the ranges of the inputting magnetic fields are different, the three materials' neurons can all reach the saturation accuracy. It is expected to replace the traditional CMOS neuron. And the overall power consumption of intelligent computing can be further reduced by using appropriate materials. If we input the magnetic fields in the same range, the recognition speed of the spin neuron made of Ni is the slowest in the three materials. The results can establish a theoretical foundation for the design and the applications of the new artificial neural networks and the intelligent circuits. © 2021 Chinese Physical Society.","Magnetization switching; Nanomagnet; Neural network computing; Spin neuron","Binary alloys; Brain; Character recognition; Chemical activation; Computer software; Electric power utilization; Iron alloys; Magnetic fields; Multilayer neural networks; Network layers; Activation functions; Computing performance; Magnetic-field; Magnetization switching; Nanomagnets; Network computing; Neural devices; Neural network computing; Neural-networks; Spin neuron; Neurons","","","","","Natural Science Basic Research Program of Shaanxi, China, (2020JQ-470, 2021JM-221); National Natural Science Foundation of China, NSFC, (11975311)","* Project supported by the National Natural Science Foundation of China (Grant No. 11975311) and the Natural Science Basic Research Program of Shaanxi, China (Grant Nos. 2021JM-221, 2020JQ-470). . † Corresponding author. E-mail: yangxk0123@163.com","Aleksander I, Nature, 432, (2004); Linares-Barranco B, Sanchez-Sinencio E, Rodriguez-Vazquez A, Huertas J L, IEEE J. Solid-State Circuits, 26, (1991); Lont J B, Guggenbuhl W, IEEE Trans. Neural Networks, 3, (1992); Chen Y R, Li H, Chen Y Z, Chen F, Li S C, Liu C C, Wen W J, Wu C P, Yan B N, AI-View, 2, (2018); Yang R, Terabe K, Yao Y P, Tsuruoka T, Hasegawa T, Gimzewski J K, Aono M, Nanotechnology, 24, (2013); Chen C, Yang M, Liu S, Liu T, Zhu K, Zhao Y, Wang H, Huang Q, Huang R, Symposium on VLSI Technology, (2019); Liu D Q, Cheng H F, Zhu X, Wang N N, Zhang C Y, Acta Phys. Sin, 63, (2014); Tuma T, Pantazi A, Gallo M L, Sebastian A, Eleftheriou E, Nat. Nanotechnol, 11, (2016); Cai J L, Fang B, Zhang L, Lv W X, Zhang B S, Zhou T J, Finocchio G, Zeng Z M, Phys. Rev. Appl, 11, (2019); Zhu J D, Zhang T, Yang Y C, Huang R, Appl. Phys. Rev, 7, (2020); Yue K, Liu Y Z, Lake R K, Parker A C, Sci. Adv, 5, (2019); Fukami S, Ohno H, J. Appl. Phys, 124, (2018); Sengupta A, Choday S H, Kim Y, Roy K, Appl. Phys. Lett, 106, (2015); Fulara H, Zahedinejad M, Khymyn R, Dvornik M, Fukami S, Kanai S, Ohno H, Akerman J, Nat. Commun, 11, (2020); Dong I, Yoon G, Sik H, Park Wanjun, J. Appl. Phys, 117, (2015); Vincent A F, Jerome L, Locatelli N, Nesrine B R, Bichler O, Gamrat C, Zhao W S, Klein J O, Galdin-Retailleau S, Querlioz D, IEEE T. Biomed. Circ, S9, (2015); Chen Y B, Song M X, Wei B, Yang X K, Cui H Q, Liu J H, Li C, IEEE Magn. Lett, 11, (2020); Kim Y, Fong X, Roy K, IEEE Magn. Lett, 6, (2015); Fukushima A, Seki T, Yakushiji K, Kubota H, Imamura H, Yuasa S, Ando K, Appl. Phys. Express, 7, (2014); Ostwal V, Debashis P, Faria R, Chen Z H, Appenzeller J, Sci. Rep, 8, (2018); Yang X K, Cai L, Zhang B, Cui H Q, Zhang M L, J. Magn. Magn. Mater, 394, (2015); Carlton D B, Emley N C, Tuchfeldand E, Bokor J, Nano Lett, 8, (2008); Kurenkov A, DuttaGupta S, Zhang C H, Fukami S, Horio Y, Ohno H, Adv. 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Sin, 67, (2018); Cowburn R P, Welland M E, Science, 287, (2000); Locatelli N, Cros V, Grollier J, Nat. Mater, 13, (2013); Chen Y B, Wei B, Yang X K, Liu J H, Cui H Q, Li C, Song M X, J. Magn. Magn. Mater, 514, (2020); Li X, Carka D, Liang C Y, Sepulveda A E, Keller S M, Amiri P K, Carman G P, Lynch C S, J. Appl.Phys, 118, (2015); Wang Q W, Zhang J J, Ma T Y, Yan M, Rare. Metal. Mat. Eng, 38, (2009); Bertotti G, Serpico C, Mayergoyz I D, Nonlinear Magnetization Dynamics in Nanosystems, (2009); Beleggia M, Graef M D, Millev Y T, Goode D A, Rowlands G, J. Phys. D. Appl. Phys, 38, (2005); Liyanagedera C M, Sengupta A, Jaiswal A, Roy K, Phys. Rev. Appl, 8, (2017); Glorot X, Bengio Y, J. Mach. Learn. Res, 9, (2010); Fashami M S, Atulasimha J, Bandyopadhyay S, Nanotechnology, 23, (2012); Vacca M, Graziano M, Crescenzo L D, Chiolerio A, Lamberti A, Balma D, Canavese G, Celegato F, Enrico E, Tiberto P, Boarino L, Zamboni M, IEEE Trans. Nanotechnol, 13, (2014); Liu J H, Yang X K, Zhang M L, Wei B, Li C, Dong D N, Li C, IEEE Electron Device Lett, 40, (2018); Das J, Alam S M, Bhanja S, IEEE J. Emerg. Sel. Top. Circuits Syst, 1, (2011)","X.-K. Yang; Fundamentals Department, Air Force Engineering University, Xi'an, 710051, China; email: yangxk0123@163.com","","Institute of Physics, Chinese Academy of Sciences","","","","","","10003290","","WLHPA","","Chinese","Wuli Xuebao","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85117601890" +"Miyashita S.; Nishino M.; Toga Y.; Hinokihara T.; Uysal I.E.; Miyake T.; Akai H.; Hirosawa S.; Sakuma A.","Miyashita, Seiji (7102333760); Nishino, Masamichi (7103009415); Toga, Yuta (26532037600); Hinokihara, Taichi (55329793900); Uysal, Ismail Enes (56441165200); Miyake, Takashi (7202951411); Akai, Hisazumi (7004859390); Hirosawa, Satoshi (7103189702); Sakuma, Akimasa (7102719646)","7102333760; 7103009415; 26532037600; 55329793900; 56441165200; 7202951411; 7004859390; 7103189702; 7102719646","Atomistic theory of thermally activated magnetization processes in Nd2Fe14B permanent magnet","2021","Science and Technology of Advanced Materials","22","1","","658","682","24","15","10.1080/14686996.2021.1942197","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85114305144&doi=10.1080%2f14686996.2021.1942197&partnerID=40&md5=4935116e02b2b694b8512594190ec249","The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Japan; Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), Tsukuba, Japan; Elements Strategy Initiative Center for Magnetic Materials, Research Center for Magnetic and Spintronics Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan; The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Department of Applied Physics, Tohoku University, Sendai, Japan","Miyashita S., The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Japan; Nishino M., Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), Tsukuba, Japan; Toga Y., The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Japan; Hinokihara T., The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Japan; Uysal I.E., Elements Strategy Initiative Center for Magnetic Materials, Research Center for Magnetic and Spintronics Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan; Miyake T., The National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan; Akai H., The Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Japan; Hirosawa S., Elements Strategy Initiative Center for Magnetic Materials, Research Center for Magnetic and Spintronics Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan; Sakuma A., Department of Applied Physics, Tohoku University, Sendai, Japan","To study the temperature dependence of magnetic properties of permanent magnets, methods of treating the thermal fluctuation causing the thermal activation phenomena must be established. To study finite-temperature properties quantitatively, we need atomistic energy information to calculate the canonical distribution. In the present review, we report our recent studies on the thermal properties of the Nd2Fe14B magnet and the methods of studying them. We first propose an atomistic Hamiltonian and show various thermodynamic properties, for example, the temperature dependences of the magnetization showing a spin reorientation transition, the magnetic anisotropy energy, the domain wall profiles, the anisotropy of the exchange stiffness constant, and the spectrum of ferromagnetic resonance. The effects of the dipole–dipole interaction (DDI) in large grains are also presented. In addition to these equilibrium properties, the temperature dependence of the coercivity of a single grain was studied using the stochastic Landau-Lifshitz-Gilbert equation and also by the analysis of the free energy landscape, which was obtained by Monte Carlo simulation. The upper limit of coercivity at room temperature was found to be about 3 T at room temperature. The coercivity of a polycrystalline magnet, that is, an ensemble of interactinve grains, is expected to be reduced further by the effects of the grain boundary phase, which is also studied. Surface nucleation is a key ingredient in the domain wall depinning process. Finally, we study the effect of DDI among grains and also discuss the distribution of properties of grains from the viewpoint of first-order reversal curve. © 2021 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.","40 Optical, magnetic and electronic device materials; 203 Magnetics / Spintronics / Superconductors; 400 Modeling/Simulations; Coercivity; dipole–dipole interaction; finite temperature; Monte Carlo method; stochastic LLG equation; thermal fluctuation","Coercive force; Domain walls; Drug interactions; Free energy; Grain boundaries; Hamiltonians; Iron compounds; Magnetic anisotropy; Magnetization; Monte Carlo methods; Neodymium alloys; Permanent magnets; Stochastic systems; Temperature distribution; Canonical distributions; Equilibrium properties; First-order reversal curves; Landau-Lifshitz-Gilbert equations; Magnetic anisotropy energy; Spin reorientation transitions; Temperature dependence; Temperature dependence of magnetic properties; Boron compounds","","","","","ACCMS; ISSP University of Tokyo, Kyoto University; Research Institute for Information Technology, Kyushu University, RIIT; Kyushu University; National Institute for Materials Science, NIMS; Professors Roy Chantrell; Bernard Barbara; Ministry of Education, Culture, Sports, Science and Technology, MEXT; MEXT Program for Promoting Researches, (hp200125, 18K03444, 20K05311, 20K03809); Japan Society for the Promotion of Science, JSPS, (21K03397); Dominique Givord, (JPMXP0112101004)","The authors thank Professors Roy Chantrell, Bernard Barbara, Dominique Givord, Alexandru Stancu, Thomas Shirefl, Dietter Suess, Nora Dempsey, and members of ESICMM for fruitful discussions during our works presented in this review. This work was supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM), Grant Number JPMXP0112101004, through the Ministry of Education, Culture, Sports, Science and Technology (MEXT), and also by the MEXT Program for Promoting Researches on the Supercomputer Fugaku (DPMSD, Project ID: hp200125). It was also partially supported by Grants-in-Aid for Scientific Research C (Nos. 18K03444, 20K03809, and 20K05311) from MEXT. The numerical calculations were performed on supercomputers at National Institute for Materials Science (Numerical Materials Simulator), ISSP University of Tokyo, Kyoto University (ACCMS), and Kyushu University (RIIT). 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Miyashita; ISSP, University of Tokyo, Kashiwa, Japan; email: miyashita@phys.s.su-tokyo.ac.jp","","Taylor and Francis Ltd.","","","","","","14686996","","","","English","Sci. Technol. Adv. Mater.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85114305144" +"Song W.; Yang G.","Song, Wenjing (56662627900); Yang, Ganshan (8263184300)","56662627900; 8263184300","Vanishing Gilbert damping limit problem of Landau–Lifshitz–Gilbert equation","2022","ZAMM Zeitschrift fur Angewandte Mathematik und Mechanik","102","8","e202100136","","","","1","10.1002/zamm.202100136","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85132636642&doi=10.1002%2fzamm.202100136&partnerID=40&md5=ffd0115a090b90a1e7f02e9d2d8fb20c","School of Science, Xi'an Polytechnic University, Xi'an, China; Department of Mathematics, Yunnan Nationalities University, Kunming, China","Song W., School of Science, Xi'an Polytechnic University, Xi'an, China; Yang G., Department of Mathematics, Yunnan Nationalities University, Kunming, China","The vanishing Gilbert damping limit problem of the Landau–Lifshitz–Gilbert (LLG) equation has been an open problem for a long time, and even the explicit dynamic solution of LLG equation has not been seen so far. In this paper, a necessary and sufficient condition for a solution of Landau–Lifshitz (LL) equation to be generalized to a solution of LLG equation is given. Moreover, some explicit dynamic solutions of LLG equation are constructed. These solutions show that a solution of LLG equation with Gilbert damping does not necessarily tend to a solution of LL equation without Gilbert damping in the sense of maximum modulus. © 2022 Wiley-VCH GmbH.","","Dynamic solutions; Explicit dynamics; Gilbert damping; Landau Lifshitz equation; Landau-Lifshitz-Gilbert equations; Limit problem; Maximum modulus; Damping","","","","","National Natural Science Foundation of China, NSFC, (11561076, 11961080, 12001415)","The author would like to thank Professor Boling Guo and Professor Zhouping Xin for their constant encouragement and support. This project is supported by National Natural Science Foundation of China 12001415, 11961080, 11561076.","Landau L.D., Lifshitz E.M., On the Theory of the Dispersion of Magnetic Permeability in Ferromagnetic Bodies, Z. Sowjetunion, 8, 1965, pp. 101-114, (1935); Nakamura K., Sasada T., Solition and wave trains in ferromagnets, Phys. Lett., A 48, pp. 321-322, (1974); Lakshmanan M., Continuum spin system as an exactly solvable dynamical system, Phys. Lett., A 61, pp. 53-54, (1977); Takhtajan L.A., Integration of the continuous Heisenberg spin chain through the inverse scattering method, Phys. Lett., A 64, 2, pp. 235-237, (1977); Lakshmanan M., Porsezian K., Planar radically symmetric Heisenberg spin system and generalized nonlinear Schrodinger equation: Gauge equivalence, Backlund transformations and explicit solutions, Phys. Lett., A 146, 6, pp. 329-334, (1990); Tjon J., Wright J., Soliton in the Heisenberg chain, Phys. 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Phys., 250, pp. 95-117, (2004); Liu X.G., Partial regularity for the Landau–Lifshitz system, Calc. Var., 20, pp. 153-173, (2004); Melcher C., Existence of partially regular solutions for Landau–Lifshitz equations in R3, Comm. Partial Differ. Equ., 30, pp. 567-587, (2005); Wang C.Y., On Landau–Lifshitz equation in dimensions at most four, Indiana Univ. Math. J., 55, pp. 1615-1644, (2006); Merle F., Raphael P., Rodnianski I., Blowup dynamics for smooth data equivariant solutions to the critical Schrödinger map problem, Invent Math., 193, pp. 249-365, (2013); Bejenaru I., Ionescu A.D., Kenig C.E., Tataru D., Global Schrödinger maps in dimensions d≥2$d\ge 2$: Small data in the critical Sobolev spaces, Ann. Math., 173, pp. 1443-1506, (2011); Guo B.L., Wang Y.D., Generalized Landau–Lifshitz systems and harmonic maps, Sci. China Ser., A 39, pp. 1242-1257, (1996); Chang N., Shatah J., Uhlandeck K., Schrodinger maps, Comm. Pure Appl. Math., 53, pp. 590-602, (2000); Yang G.S., Guo B.L., Some exact solutions to multidimensional Landau–Lifshitz equation with uprush external field and anisotropy field, Nonlinear Anal., 71, pp. 3999-4006, (2009); Guo Z.H., Huang C.Y., The inviscid limit for the Landau–Lifshitz–Gilbert equation in the critical Besov space, Sci. China Math., 60, pp. 2155-2172, (2017); Fratta G.D., Innerberger M., Praetorius D., Weak-strong uniqueness for the Landau–Lifshitz–Gilbert equation in micromagnetics, Nonlinear Anal. Real World Appl., 55, (2020)","G. Yang; Department of Mathematics, Yunnan Nationalities University, Kunming, China; email: ganshanyang@aliyun.com","","John Wiley and Sons Inc","","","","","","00442267","","","","English","ZAMM Z. Angew. Math. Mech.","Article","Final","","Scopus","2-s2.0-85132636642" +"Sun J.Z.","Sun, Jonathan Z. (7410371463)","7410371463","Precession coupled spin current in spin torque driven magnetic tunnel junctions","2021","AIP Advances","11","1","015006","","","","2","10.1063/9.0000020","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85099244419&doi=10.1063%2f9.0000020&partnerID=40&md5=a4c61e89c7b764463c3f273961e66eb8","Ibm T. J. Watson Research Center, Yorktown Heights, 10598, NY, United States","Sun J.Z., Ibm T. J. Watson Research Center, Yorktown Heights, 10598, NY, United States","A spin-torque switchable magnetic tunnel junction contains two ferromagnetic electrodes across a barrier that supports spin-polarized tunnel current. The spin-torque induced magnetic switching of its more agile, or ""free""layer provides the ""write""mechanism. Often the dynamics of the non-switching ""reference""layer is also important. Here, we illustrate such dynamics involving both the free and the reference layers by using an exchange-coupled two-macrospin-moment numerical model, described by a set of Landau-Lifshitz-Gilbert (LLG) equations, together with a stochastic Langevin-field for finite temperature. Damping-like spin-transfer torque is included for both moments. In steady-state, the coupled precession is shown to reduce effective spin-current delivered to the free layer due to a precessional resonant spin-current back flow. This back-flow of spin current preferentially affects the parallel state dynamics. It is not directly related to the reference layer's thermal stability, nor its spin-torque switching threshold, as determined by the total anisotropy energy and magnetic volume. Rather, the spin-current reduction relates primarily to the matching of precession frequency between the free- and the reference-layer. Therefore, a desirable materials choice is to avoid anisotropy fields giving the free and the reference layer similar dynamic frequencies, so as to prevent such resonance-related spin-current loss. © 2021 Author(s).","","Dynamics; Magnetic anisotropy; Magnetic devices; Magnetism; Stochastic models; Stochastic systems; Torque; Tunnel junctions; Anisotropy energies; Ferromagnetic electrodes; Finite temperatures; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Precession frequency; Spin transfer torque; Spin-torque switching; Spin fluctuations","","","","","","","Kittel C., Phys. Rev., 73, (1948); Sun J.Z., Phys. Rev. B, 96, (2017); Huai Y., Albert F., Nguyen P., Pakala M., Valet T., Appl. Phys. Lett., 84, (2004); Slonczewski J.C., Phys. Rev. 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Mech, 2014; Slonczewski J.C., Phys. Rev. B, 71, (2005); Pinna D., Kent A.D., Stein D.L., Phys. Rev. B, 88, (2013); Yamanouchi M., Jander A., Dhagat P., Ikeda S., Matsukura F., Ohno H., Ieee Magn. Lett., 2, (2011); Dohi T., Kanai S., Okada A., Matsukura F., Ohno H., Aip Advances, 6, (2016); Dohi T., Kanai S., Matsukura F., Ohno H., Appl. Phys. Lett., 111, (2017); Safranski C.J., Chen Y.-J., Krivorotov I.N., Sun J.Z., Appl. Phys. Lett., 109, (2016); Sun J.Z., Brown S.L., Chen W., Delenia E.A., Gaidis M.C., Harms J., Hu G., Jiang X., Kilaru R., Kula W., Lauer G., Liu L.Q., Murthy S., Nowak J., O'Sullivan E.J., Parkin S.S.P., Robertazzi R.P., Rice P.M., Sandhu G., Topuria T., Worledge D.C., Phys. Rev. B, 88, (2013); Barsukov I., Lee H.K., Jara A.A., Chen Y.-J., Goncalves A.M., Sha C., Katine J.A., Arias R.E., Ivanov B.A., Krivorotov I.N., Sci. Adv., 5, (2019)","J.Z. Sun; Ibm T. J. Watson Research Center, Yorktown Heights, 10598, United States; email: jonsun@us.ibm.com","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85099244419" +"Saldanha-Bautista D.E.; Padrón-Hernández E.","Saldanha-Bautista, D.E. (57927749300); Padrón-Hernández, E. (6504643531)","57927749300; 6504643531","Magnetostatic modes in a hollow ferromagnetic sphere","2022","Physics Letters, Section A: General, Atomic and Solid State Physics","453","","128494","","","","3","10.1016/j.physleta.2022.128494","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85139845882&doi=10.1016%2fj.physleta.2022.128494&partnerID=40&md5=3a9fe4bbae13de5842284c73edcbec4e","Universidade Federal de Pernambuco, Departamento de Física, PE, Recife, Brazil; Universidade Federal de Pernambuco, Pós-Graduação em Ciência de Materiais, PE, Recife, Brazil","Saldanha-Bautista D.E., Universidade Federal de Pernambuco, Departamento de Física, PE, Recife, Brazil; Padrón-Hernández E., Universidade Federal de Pernambuco, Departamento de Física, PE, Recife, Brazil, Universidade Federal de Pernambuco, Pós-Graduação em Ciência de Materiais, PE, Recife, Brazil","A study about magnetostatic modes in a hollow sphere of inner radius r1 and outer radius r2, is presented. The eigenfrequencies are represented as a function of r1/r2 (the aspect ratio). Walker's solution for the sphere was recovered in the representation obtained by Plumier. The equations for hollow spheres correspond to the results obtained by micromagnetic simulation in these geometries. The results presented here are significant for future experimental investigations and technological applications. © 2022 Elsevier B.V.","Ferromagnetic sphere; Hollow sphere; LLG equation; Magnetostatic modes","Aspect ratio; Ferromagnetic materials; Ferromagnetism; Magnetostatics; Aspect-ratio; Eigenfrequency; Experimental investigations; Ferromagnetic sphere; Ferromagnetics; Hollow sphere; LLG equation; Magnetostatic modes; Micromagnetic simulations; Technological applications; Spheres","","","","","Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq; Financiadora de Estudos e Projetos, FINEP; Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco, FACEPE","The authors are grateful to the Brazilian Agencies: CAPES; CNPq; FINEP and FACEPE.","Hurben M., Patton C., Theory of magnetostatic waves for in-plane magnetized isotropic films, J. Magn. Magn. Mater., 139, (1995); Holstein T., Primakoff H., Field dependence of the intrinsic domain magnetization of a ferromagnet, Phys. Rev., 58, (1940); Van Vleck J., Ferromagnetic resonance, Physica, 17, (1951); Phillips T.G., Rosemberg H.M., Spin waves in ferromagnets, Rep. Prog. Phys., 29, (1966); Lee S., Grudichak S., Sklenar J., Tsai C.C., Jang M., Yang Q., Zhang H., Ketterson J.B., Ferromagnetic resonance of a yig film in the low frequency regime, J. Appl. Phys., 120, (2016); Rezende S.M., Fundamentals of Magnonics, (2020); Walker L.R., Magnetostatic modes in ferromagnetic resonance, Phys. Rev., 105, (1957); Eshbach J., Damon R., Surface magnetostatic modes and surface spin waves, Phys. Rev., 118, (1960); Sakharov V.K., Khivintsev Y.V., Stognij A.I., Vysotskii S.L., Filimonov Y.A., Beginin E.N., Sadovnikov A.V., Nikitov S.A., Spin-wave excitations in YIG films grown on corrugated substrates, J. Phys. Conf. Ser., 1389, (2019); Ansalone P., Basso V., Walker's modes in ferromagnetic finite hollow cylinder, Physica B, 578, (2020); Korber L., Kezsmarki I., Kakay A., Mode splitting of spin waves in magnetic nanotubes with discrete symmetries; Prat-Camps J., Navau C., Sanchez A., Chen D.-X., Demagnetizing factors for a hollow sphere, IEEE Magn. Lett., 7, (2016); Goll D., Berkowitz A.E., Bertram H.N., Critical sizes for ferromagnetic spherical hollow nanoparticles, Phys. Rev. B, 70, (2004); Krupka J., Pacewicz A., Salski B., Kopyt P., Bourhill J., Goryachev M., Tobar M., Electrodynamic improvements to the theory of magnetostatic modes in ferrimagnetic spheres and their applications to saturation magnetization measurements, J. Magn. Magn. Mater., 487, (2019); Kravchuk V.P., Rossler U.K., Volkov O.M., Sheka D.D., van den Brink J., Makarov D., Fuchs H., Fangohr H., Gaididei Y., Topologically stable magnetization states on a spherical shell: curvature-stabilized skyrmions, Phys. Rev. B, 94, (2016); McKeever C., Ogrin F.Y., Aziz M.M., Microwave magnetization dynamics in ferromagnetic spherical nanoshells, Phys. Rev. B, 100, (2019); Dobrovolskiy O.V., Bunyaev S.A., Vovk N.R., Navas D., Gruszecki P., Krawczyk M., Sachser R., Huth M., Chumak A.V., Guslienko K.Y., Kakazei G.N., Spin-wave spectroscopy of individual ferromagnetic nanodisks, Nanoscale, 12, (2020); Plumier R., Magnetostatic modes in a sphere and polarization current corrections, Physica, 28, (1961); Zhang Y., Li G., Zhang L., Synthesis of indium hollow spheres and nanotubes by a simple template-free solvothermal process, Inorg. Chem. Commun., 7, (2004); Nguyen H.T., Cottam M.G., Dipole-exchange spin waves in ferromagnetic nanostructures with spherical geometries, Surf. Rev. Lett., 15, pp. 727-744, (2008); Aharoni A., Exchange resonance modes in a hollow sphere, Phys. Status Solidi (b), 231, pp. 547-553, (2002)","E. Padrón-Hernández; Universidade Federal de Pernambuco, Departamento de Física, Recife, PE, Brazil; email: eduardo.hernandez@ufpe.br","","Elsevier B.V.","","","","","","03759601","","PYLAA","","English","Phys Lett Sect A Gen At Solid State Phys","Article","Final","","Scopus","2-s2.0-85139845882" +"Huang L.; Meng J.; Zhu D.; Yuan Y.","Huang, Liyang (56818163000); Meng, Jin (35201482900); Zhu, Danni (56069641400); Yuan, Yuzhang (56161158600)","56818163000; 35201482900; 56069641400; 56161158600","Field-line coupling method for the simulation of gyromagnetic nonlinear transmission line based on the maxwell-LLG system","2020","IEEE Transactions on Plasma Science","48","11","9229148","3847","3853","6","13","10.1109/TPS.2020.3029524","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85096124885&doi=10.1109%2fTPS.2020.3029524&partnerID=40&md5=ab5aff87dd0b8348b57bfdd7fce8ad1d","National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China","Huang L., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Meng J., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Zhu D., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Yuan Y., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China","The gyromagnetic nonlinear transmission line (GNLTL) is a compact and solid-state high-power microwave source, which can be treated as a special coaxial transmission line partially filled with the ferrite material. Due to the complex interaction process of the electromagnetic fields with the dynamic damped precessional motion of the magnetization vector in the ferrite, it is of great challenge to theoretically predict the output of the GNLTL. Here, we present a novel field-line coupling simulation method to predict the output waveform of the GNLTL by simultaneously solving the coupled system of the Landau-Lifshitz-Gilbert equation and Maxwell's equations in the 2-D cylindrical coordinate system. In particular, the simulation model is validated by comparing the computation results with the experimental results obtained by Bragg et al. in the HPM experiment. The influences of the GNLTL length and bias magnetic field are analyzed. The proposed computation method can provide a solution for improving the performance of the GNLTL. © 1973-2012 IEEE.","Gyromagnetic nonlinear transmission line (GNTL); high-power microwave (HPM); Landau-Lifshitz-Gilbert (LLG) equation","Electric lines; Electromagnetic fields; Ferrite; Maxwell equations; Microwaves; 2-D cylindrical coordinate system; Coaxial transmission lines; Computation methods; Coupling simulation; High power microwave sources; Landau-Lifshitz-Gilbert equations; Magnetization vector; Nonlinear transmission lines; Transmissions","","","","","National Natural Science Foundation of China, NSFC, (51907202)","Manuscript received July 3, 2020; revised September 16, 2020; accepted October 5, 2020. Date of publication October 19, 2020; date of current version November 10, 2020. This work was supported by the National Natural Science Foundation of China under Grant 51907202. The review of this article was arranged by Senior Editor D. A. Shiffler. (Corresponding author: Jin Meng.) The authors are with the National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan 430000, China (e-mail:huangliyang@foxmail.com; mengjinemc@163.com; 360681625@qq.com; yuanyuzhang206@163.com).","Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, J. Appl. Phys., 117, 21, (2015); Yamasaki F.S., Rossi J.O., Barroso J.J., Schamiloglu E., Operation of a gyromagnetic line at low and high voltages with simultaneous axial and azimuthal biases, Ieee Trans. Plasma Sci., 46, 7, pp. 2573-2581, (2018); Tie W., Et al., Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application, Plasma Sci. Technol., 21, 9, (2019); Rostov V.V., Bykov N.M., Bykov D.N., Klimov A.I., Kovalchuk O.B., Romanchenko I.V., Generation of subgigawatt RF pulses in nonlinear transmission lines, Ieee Trans. Plasma Sci., 38, 10, pp. 2681-2685, (2010); Bragg J.-W.-B., Dickens J.C., Neuber A.A., Ferrimagnetic nonlinear transmission lines as high-power microwave sources, Ieee Trans. Plasma Sci., 41, 1, pp. 232-237, (2013); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., Gyromagnetic RF source for interdisciplinary research, Rev. Sci. Instrum., 88, 2, (2017); Gusev A.I., Pedos M.S., Rukin S.N., Timoshenkov S.P., Solidstate repetitive generator with a gyromagnetic nonlinear transmission line operating as a peak power amplifier, Rev. Sci. Instrum., 88, 7, (2017); Johnson J.M., Et al., Characteristics of a four element gyromagnetic nonlinear transmission line array high power microwave source, Rev. Sci. Instrum., 87, 5, (2016); Ulmaskulov M.R., Shunailov S.A., Sharypov K.A., Yalandin M.I., Multistage converter of high-voltage subnanosecond pulses based on nonlinear transmission lines, J. Appl. Phys., 126, 8, (2019); Ulmaskulov M.R., Et al., Four-channel generator of 8-GHz radiation based on gyromagnetic non-linear transmitting lines, Rev. Sci. Instrum., 90, 6, (2019); Yao Z., Tok R.U., Itoh T., Wang Y.E., A multiscale unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics, Ieee Trans. Microw. Theory Techn., 66, 6, pp. 2683-2696, (2018); Dolan J.E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, J. Phys. D: Appl. Phys., 32, 15, pp. 1826-1831, (1999); Dolan J.E., Bolton H.R., Shock front development in ferrite-loaded coaxial lines with axial bias, Iee Proc. Sci., Meas. Technol., 147, 5, pp. 237-242, (2000); Yamasaki F.S., Schamiloglu E., Rossi J.O., Barroso J.J., Simulation studies of distributed nonlinear gyromagnetic lines based on LC lumped model, Ieee Trans. Plasma Sci., 44, 10, pp. 2232-2239, (2016); Romanchenko I.V., Priputnev P.V., Rostov V.V., RF pulse formation dynamics in gyromagnetic nonlinear transmission lines, J. Phys.: Conf. Ser., 830, (2017); Karelin S.Y., Krasovitsky V.B., Magda I.I., Mukhin V.S., Sinitsin V.G., Radio frequency oscillations in gyrotropic nonlinear transmission lines, Plasma, 2, 2, pp. 258-271, (2019); Bragg J.-W.-B., Sullivan W.W., Mauch D., Neuber A.A., Dickens J.C., All solid-state high power microwave source with high repetition frequency, Rev. Scientific Instrum., 84, 5, (2013); Landau L.D., Lifshitz L.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Landau L.D., Bell J.S., Kearsley M.J., Pitaevskii L.P., Electrodynamics of Continuous Media, 8, (2013); Gilbert T.L., Classics in magnetics a phenomenological theory of damping in ferromagnetic materials, Ieee Trans. Magn., 40, 6, pp. 3443-3449, (2004); Esquinazi P., Magnetic Carbon, Handbook of Magnetism and Adanced Magnetic Materials, 2, pp. 730-731, (2007); Aziz M.M., McKeever C., Wide-band electromagnetic wave propagation and resonance in long cobalt nanoprisms, Phys. Rev. A, Gen. Phys., 13, 3, (2020); Rado G.T., Weertman J.R., Spin-wave resonance in a ferromagnetic metal, J. Phys. Chem. Solids, 11, pp. 315-333, (1959); Reale D.V., Coaxial Ferromagnetic Based Gyromagnetic Transmission Lines As Compact High Power Microwave Sources, (2013); Romanchenko I.V., Rostov V.V., Gubanov V.P., Stepchenko A.S., Gunin A.V., Kurkan I.K., Repetitive sub-gigawatt rf source based on gyromagnetic nonlinear transmission line, Rev. Sci. Instrum., 83, 7, (2012)","J. Meng; National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; email: mengjinemc@163.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00933813","","ITPSB","","English","IEEE Trans Plasma Sci","Article","Final","","Scopus","2-s2.0-85096124885" +"Gutiérrez S.; de Laire A.","Gutiérrez, Susana (56239017900); de Laire, André (26040620600)","56239017900; 26040620600","Self-similar shrinkers of the one-dimensional Landau–Lifshitz–Gilbert equation","2021","Journal of Evolution Equations","21","1","","473","501","28","2","10.1007/s00028-020-00589-8","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85086360156&doi=10.1007%2fs00028-020-00589-8&partnerID=40&md5=aebf754e8343acd3ee78a379014d88b0","School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; CNRS, UMR 8524, Inria - Laboratoire Paul Painlevé, Univ. Lille, Lille, 59000, France","Gutiérrez S., School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; de Laire A., CNRS, UMR 8524, Inria - Laboratoire Paul Painlevé, Univ. Lille, Lille, 59000, France","The main purpose of this paper is the analytical study of self-shrinker solutions of the one-dimensional Landau–Lifshitz–Gilbert equation (LLG), a model describing the dynamics for the spin in ferromagnetic materials. We show that there is a unique smooth family of backward self-similar solutions to the LLG equation, up to symmetries, and we establish their asymptotics. Moreover, we obtain that in the presence of damping, the trajectories of the self-similar profiles converge to great circles on the sphere S2, at an exponential rate. In particular, the results presented in this paper provide examples of blow-up in finite time, where the singularity develops due to rapid oscillations forming limit circles. © 2020, Springer Nature Switzerland AG.","Asymptotics; Backward self-similar solutions; Blow up; Ferromagnetic spin chain; Heat flow for harmonic maps; Landau–Lifshitz–Gilbert equation; Quasi-harmonic sphere; Self-similar expanders","","","","","","ERCEA, (2014 669689—HADE); Labex CEMPI, (ANR-11-LABX-0007-01, ANR-18-CE40-0020-01); Horizon 2020 Framework Programme, H2020, (669689)","S. Gutiérrez was partially supported by ERCEA Advanced Grant 2014 669689—HADE. The Université de Lille also supported S. Gutiérrez’s research visit during July 2018 through their Invited Research Speaker Scheme. A. de Laire was partially supported by the Labex CEMPI (ANR-11-LABX-0007-01), the ANR project “Dispersive and random waves” (ANR-18-CE40-0020-01), and the MATH-AmSud Project EEQUADD-II. ","Abramowitz M., Stegun I.A., Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, Volume 55 of National Bureau of Standards Applied Mathematics Series. for Sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C, (1964); Amann H., Quasilinear parabolic systems under nonlinear boundary conditions, Arch. Rational Mech. Anal., 92, 2, pp. 153-192, (1986); Banica V., Vega L., On the stability of a singular vortex dynamics, Comm. Math. Phys., 286, 2, pp. 593-627, (2009); Banica V., Vega L., Singularity formation for the 1-D cubic NLS and the Schrödinger map on S2, Commun. Pure Appl. Anal., 17, 4, pp. 1317-1329, (2018); Bidaut-Veron M.F., Self-similar solutions of the p -Laplace heat equation: the case when p> 2, Proc. Roy. Soc. Edinburgh Sect. A, 139, 1, pp. 1-43, (2009); Biernat P., Bizon P., Shrinkers, expanders, and the unique continuation beyond generic blowup in the heat flow for harmonic maps between spheres, Nonlinearity, 24, 8, pp. 2211-2228, (2011); Biernat P., Donninger R., Construction of a spectrally stable self-similar blowup solution to the supercritical corotational harmonic map heat flow, Nonlinearity, 31, 8, (2018); Bizon P., Wasserman A., Nonexistence of shrinkers for the harmonic map flow in higher dimensions, Int. Math. Res. Not. IMRN, 17, pp. 7757-7762, (2015); Broggi G., Meier P.F., Stoop R., Badii R., Nonlinear dynamics of a model for parallel pumping in ferromagnets, Phys. Rev. A, 35, pp. 365-368, (1987); Buttke T.F., A numerical study of superfluid turbulence in the self-induction approximation, Journal of Computational Physics, 76, 2, pp. 301-326, (1988); Généralités. Coordonnées curvilignes. Surfaces minima. [Generalities. Curvilinear coordinates. Minimum surfaces], Les congruences et les équations linéaires aux dérivées partielles. Les lignes tracées sur les surfaces. [Congruences and linear partial differential equations. Lines traced on surfaces], Reprint of the Second (1914) Edition (I) and the Second (1915) Edition, (1993); de Laire A., Minimal energy for the traveling waves of the Landau-Lifshitz equation, SIAM J. Math. Anal., 46, 1, pp. 96-132, (2014); de Laire A., Gravejat P., Stability in the energy space for chains of solitons of the Landau–Lifshitz equation, J. Differential Equations, 258, 1, pp. 1-80, (2015); de Laire A., Gravejat P., The Sine-Gordon regime of the Landau–Lifshitz equation with a strong easy-plane anisotropy, Ann. Inst. Henri Poincaré, Analyse Non Linéaire, 35, 7, pp. 1885-1945, (2018); de Laire A., Gravejat P.; Demontis F., Ortenzi G., Sommacal M., Heisenberg ferromagnetism as an evolution of a spherical indicatrix: localized solutions and elliptic dispersionless reduction, Electron. J. Differential Equations, 106, pp. 1-34, (2018); Deruelle A., Lamm T., (1801); Eggers J., Fontelos M.A., The role of self-similarity in singularities of partial differential equations, Nonlinearity, 22, 1, pp. 1-9, (2009); Fan H., Existence of the self-similar solutions in the heat flow of harmonic maps, Sci. China Ser. A, 42, 2, pp. 113-132, (1999); Gamayun O., Lisovyy O.; Gastel A., Singularities of first kind in the harmonic map and Yang–Mills heat flows, Math. Z., 242, 1, pp. 47-62, (2002); Germain P., Ghoul T.-E., Miura H., On uniqueness for the harmonic map heat flow in supercritical dimensions, Comm. Pure Appl. Math., 70, 12, pp. 2247-2299, (2017); Germain P., Rupflin M., Selfsimilar expanders of the harmonic map flow, Ann. Inst. H. Poincaré Anal. Non Linéaire, 28, 5, pp. 743-773, (2011); Germain P., Shatah J., Zeng C., Self-similar solutions for the Schrödinger map equation, Math. Z., 264, 3, pp. 697-707, (2010); Volume 105 of Annals of Mathematics Studies, (1983); Giga M.-H., Giga Y., Saal J.; Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetization field, Phys. Rev., 100, (1955); Gordon R.D., Values of Mills’ ratio of area to bounding ordinate and of the normal probability integral for large values of the argument, Ann. Math. Statistics, 12, pp. 364-366, (1941); Pte, (2008); Guo B.L., Hong M.C., The Landau–Lifshitz equation of the ferromagnetic spin chain and harmonic maps, Calc. Var. Partial Differential Equations, 1, 3, pp. 311-334, (1993); Gutierrez S., Vortex filaments and 1D cubic Schrödinger equations: singularity formation, Commun. Appl. Anal., 15, 2-4, pp. 457-474, (2011); Gutierrez S., de Laire A., Self-similar solutions of the one-dimensional Landau–Lifshitz–Gilbert equation, Nonlinearity, 28, 5, pp. 1307-1350, (2015); Gutierrez S., de Laire A., The Cauchy problem for the Landau–Lifshitz–Gilbert equation in BMO and self-similar solutions, Nonlinearity, 32, 7, pp. 2522-2563, (2019); Gutierrez S., Rivas J., Vega L., Formation of singularities and self-similar vortex motion under the localized induction approximation, Comm. Partial Differential Equations, 28, 5-6, pp. 927-968, (2003); Gutierrez S., Vega L., Self-similar solutions of the localized induction approximation: singularity formation, Nonlinearity, 17, pp. 2091-2136, (2004); Ilmanen T., Lectures on Mean Curvature Flow and Related Equations (Lecture Notes), (1995); Jia H., Sverak V., Tsai T.-P., Self-Similar Solutions to the Nonstationary Navier–Stokes Equations; Geometry J.J.R., Analysis G., Universitext, (2008); Ladyzhenskaya O.A., Ural N.N., (1968); Lakshmanan M., The fascinating world of the Landau–Lifshitz–Gilbert equation: an overview, Philos. Trans. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci., 369, 1939, pp. 1280-1300, (2011); Lakshmanan M., Ruijgrok T.W., Thompson C., On the dynamics of a continuum spin system, Physica A: Statistical Mechanics and its Applications, 84, 3, pp. 577-590, (1976); Lamb G.L., Jr. Elements of Soliton Theory. John Wiley & Sons Inc., (1980); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Lin F., Wang C., Harmonic and quasi-harmonic spheres, Comm. Anal. Geom., 7, 2, pp. 397-429, (1999); Lin F., Wang C., The analysis of harmonic maps and their heat flows, (2008); Lipniacki T., Shape-preserving solutions for quantum vortex motion under localized induction approximation, Phys. Fluids, 15, 6, pp. 1381-1395, (2003); Montiel S., Ros A.; Quittner P., Souplet P., Superlinear Parabolic Problems. Birkhäuser Advanced Texts: Basler Lehrbücher. [Birkhäuser Advanced Texts: Basel Textbooks]; Of Lecture Notes in Mathematics, (1445); Struik D.J., Lectures on Classical Differential Geometry, (1950); Struwe M., On the evolution of harmonic maps in higher dimensions, J. Differential Geom., 28, 3, pp. 485-502, (1988); Waldner F., Barberis D.R., Yamazaki H., Route to chaos by irregular periods: Simulations of parallel pumping in ferromagnets, Phys. Rev. A, 31, pp. 420-431, (1985); Micromagnetics D.W., Materials R., SpringerBriefs in Applied Sciences and Technology, Springer Berlin Heidelberg, (2012); Xu D., Zhou C., A remark on the quasi-harmonic spheres, Appl. Math. J. Chinese Univ. Ser. B, 17, 2, pp. 164-170, (2002)","A. de Laire; CNRS, UMR 8524, Inria - Laboratoire Paul Painlevé, Univ. Lille, Lille, 59000, France; email: andre.de-laire@univ-lille.fr","","Birkhauser","","","","","","14243199","","","","English","J. Evol. Equ.","Article","Final","","Scopus","2-s2.0-85086360156" +"Fadhilah U.; Kurniawan C.; Djuhana D.","Fadhilah, U. (57208300845); Kurniawan, C. (55600299500); Djuhana, D. (26027849100)","57208300845; 55600299500; 26027849100","Hysteresis loops observation of FePt and FePd square ferromagnets using micromagnetic simulation","2020","IOP Conference Series: Materials Science and Engineering","763","1","012070","","","","0","10.1088/1757-899X/763/1/012070","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85084323841&doi=10.1088%2f1757-899X%2f763%2f1%2f012070&partnerID=40&md5=d1ddbe5fe600427c5a71222597273a0c","Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Gedung 440-442 Kawasan Puspiptek Serpong, Banten, 15314, Indonesia","Fadhilah U., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; Kurniawan C., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia, Research Center for Physics, Indonesian Institute of Sciences (LIPI), Gedung 440-442 Kawasan Puspiptek Serpong, Banten, 15314, Indonesia; Djuhana D., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia","In this study, we have investigated magnetic hysteresis loops of squared model FePt and FePd ferromagnets by a public micromagnetic simulation based on Landau-Lifshitz Gilbert (LLG) equation. The hysteresis loops of FePt and FePd ferromagnets are generated by in-plane and out-plane applied field with respect to the size and thickness variation. It is found that the coercivity field for both FePt and FePd squared ferromagnets exhibited different behavior for the size of ferromagnets around 50-100 nm and more than 100 nm. The results showed that the hysteresis loops produced a large coercivity when the in-plane field was applied and zero coercivity for external out-plane field. Interestingly, coercivity field was still observed for materials with size below 100 nm with ranging values between 20-40 mT. From this result, certain values of the coercivity field appeared for out-plane applied field at small thickness indicates a perpendicular magnetic anisotropy (PMA) behavior in FePt and FePd ferromagnets. © 2020 Published under licence by IOP Publishing Ltd.","","","","","","","Universitas Indonesia, UI","Ac k n o wle d g e m e n ts The authors would like to thank Universitas Indonesia for funding this research through PITTA Grant with contract number 2245/UN2.R3.1/HKP.05.00/2018 Re fe re n c e s [1] TuduBandTiwariA2017Vacuum146329–41 [2] PurnamaB,IsmailandSuharyana2013JurnalFisikadanAplikasinya930–3 [3] LukaszewRA,CebolladaA,ClaveroCandGarcia-Martín JM2006 PhysicaB 38415–8 [4] IvanovOA,SolinaLV,DemshinaVAandMagatL M1973Phys.MetalsMetallogr.3581–5 [5] MitaniS,TsukamotoK,SekiT,ShimaTandTakanashiK2005IEEETrans.Magn.412606–8 [6] OhtakeM,OuchiS,KirinoFandFutamotoM2012IEEETrans.Magn.483595–8 [7] Scholz W, Fidler J, Schrefl T, Suess D, Forster H, Dittrich R and Tsiantos V 2004 J. Magn. Magn. Mater. 272–276 1524–5 [8] SungHWF andRudowiczC2003J.Magn.Magn.Mater.260250–60 [9] IwamaH,DoiMandShimaT2016J.Magn.Soc.Jpn.4091–4 [10] Skuza J R, Clavero C, Yang K, Wincheski B and Lukaszew R A 2010 IEEE Trans. Magn. 46 1886–9 [11] Bonell F, Murakami S, Shiota Y, Nozaki T, Shinjo T and Suzuki Y 2011 Appl. Phys. Lett. 98 232510 [12] Hirohata A, Sukegawa H, Yanagihara H, Žutić I, Seki T, Mizukami S and Swaminathan R 2015 IEEE Trans. Magn. 51 0800511 [13] Iihama S, Mizukami S, Naganuma H, Oogane M, Ando Y and Miyazaki T 2014 Phys. Rev. B 89 174416 [14] Donahue M J and Porter D G 1999 OOMMF User’s Guide, Version 1.0 (Gaithersburg: National Institute of Standards and Technology) [15] Gilbert T L 2004 IEEE Trans Magn. 40 3443–9 [16] Shima T, Takanashi K, Takahashi Y K and Hono K 2002 Appl. Phys. Lett. 81 1050 [17] Coey J M D 2009 Magnetism and Magnetic Materials (New York: Cambridge University Press)","Tudu B., Tiwari A., Vacuum, 146, pp. 329-341, (2017); Purnama B., Ismail S., Jurnal Fisika Dan Aplikasinya, 9, 1, pp. 30-33, (2013); Lukaszew R.A., Cebollada A., Clavero C., Garcia-Martin J.M., Physica B, 384, 1-2, pp. 15-18, (2006); Ivanov O.A., Solina L.V., Demshina V.A., Magat L.M., Phys. Metals Metallogr., 35, pp. 81-85, (1973); Mitani S., Tsukamoto K., Seki T., Shima T., Takanashi K., IEEE Trans. Magn., 41, 10, pp. 2606-2608, (2005); Ohtake M., Ouchi S., Kirino F., Futamoto M., IEEE Trans. Magn., 48, 11, pp. 3595-3598, (2012); Scholz W., Fidler J., Schrefl T., Suess D., Forster H., Dittrich R., Tsiantos V., J.Magn. Magn. Mater., 272-276, pp. 1524-1525, (2004); Sung H.W.F., Rudowicz C., J.Magn. Magn. Mater., 260, 1-2, pp. 250-260, (2003); Iwama H., Doi M., Shima T., J.Magn. Soc. Jpn., 40, 4, pp. 91-94, (2016); Skuza J.R., Clavero C., Yang K., Wincheski B., Lukaszew R.A., IEEE Trans. Magn., 46, 6, pp. 1886-1889, (2010); Bonell F., Murakami S., Shiota Y., Nozaki T., Shinjo T., Suzuki Y., Appl. Phys. Lett., 98, (2011); Hirohata A., Sukegawa H., Yanagihara H., Zutic I., Seki T., Mizukami S., Swaminathan R., IEEE Trans. Magn., 51, (2015); Iihama S., Mizukami S., Naganuma H., Oogane M., Ando Y., Miyazaki T., Phys. Rev.B, 89, (2014); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 1.0, (1999); Gilbert T.L., IEEE Trans Magn., 40, 6, pp. 3443-3449, (2004); Shima T., Takanashi K., Takahashi Y.K., Hono K., Appl. Phys. Lett., 81, 6, (2002); Coey J.M.D., Magnetism and Magnetic Materials, (2009)","D. Djuhana; Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","Anggraningrum I.T.; Triyono D.; Lee Y.-I.; Mulyana Y.; Handoko A.D.","Institute of Physics Publishing","Universitas Indonesia","3rd International Symposium on Current Progress in Functional Materials 2018, ISCPFM 2018","8 August 2018 through 9 August 2018","Depok","159473","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85084323841" +"Kurniawan C.; Widodo A.T.; Djuhana D.","Kurniawan, C. (55600299500); Widodo, A.T. (56069442000); Djuhana, D. (26027849100)","55600299500; 56069442000; 26027849100","The diameter effect on the magnetization switching time of sphere-shaped ferromagnets using micromagnetic approach","2020","IOP Conference Series: Materials Science and Engineering","902","1","012060","","","","0","10.1088/1757-899X/902/1/012060","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85096483378&doi=10.1088%2f1757-899X%2f902%2f1%2f012060&partnerID=40&md5=653c3f28723d824b60dc670095893b0f","Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Tangerang, Selatan, 15314, Indonesia","Kurniawan C., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia, Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Tangerang, Selatan, 15314, Indonesia; Widodo A.T., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia; Djuhana D., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia","In this work, the magnetization switching time has been studied as the diameter variation of sphere-shaped ferromagnets by means of micromagnetic simulation. Some ferromagnetic elements such as cobalt, iron, nickel, and permalloy were numerically simulated with diameter size variation from 50 nm to 100 nm. The micromagnetic simulation was performed by public software Object Oriented Micromagnetic Framework (OOMMF) based on the Landau-Lifshitz-Gilbert (LLG) equation. The ferromagnetic nano-sphere was induced by the quasi-static magnetic field to observe its magnetization response. Generally, it is observed that the switching time increases as the diameter size increases on the ferromagnetic elements. However, the switching time are relatively insensitive as the diameter increases in the Cobalt element for the diameter range from 60 nm to 90 nm. This behavior is contributed to the distribution of magnetization easy axis on the ferromagnetic elements. The understanding of domain structures during magnetization switching process is important in the development of nano-patterned magnetic memory storage. © Published under licence by IOP Publishing Ltd.","","","","","","","","","Sun L, Zhai Y, Niu D, Xu Y, Zhai H, IEEE Int. Magn. Conf, 51, pp. 1-4, (2015); Bhatti S, Sbiaa R, Hirohata A, Ohno H, Fukami S, Piramanayagam S N, Mater. Today, 20, pp. 530-548, (2017); Joshi V K, Eng. Sci. Technol. Int. J, 19, pp. 1503-1513, (2016); Sbiaa R, Piramanayagam S N, Phys. Status Solidi RRL-Rapid Res. Lett, 11, (2017); Mu C, Jing J, Dong J, Wang W, Xu J, Nie A, Xiang J, Wen F, Liu Z, J. Magn. Magn. Mater, 474, pp. 301-304, (2019); Ali S R, Naz F, Akber H, Naeem M, Ali S I, Basit S A, Sarim M, Qaseem S, Chin. Phys. B, 27, (2018); Oezelt H, Kovacs A, Fischbacher J, Matthes P, Kirk E, Wohlhuter P, Heyderman L J, Albrecht M, Schrefl T, J. Appl. Phys, 120, (2016); Oezelt H, Kovacs A, Wohlhuter P, Kirk E, Nissen D, Matthes P, Heyderman L J, Albrecht M, Schrefl T, J. Appl. Phys, 117, (2015); Ding J, Kakazei G N, Liu X, Guslienko K Y, Adeyeye A O, Sci. Rep, 4, (2015); Cowburn R P, Welland M E, Phys. Rev. B, 58, pp. 9217-9226, (1998); Torres-Heredia J J, Lopez-Urias F, Munoz-Sandoval E, J. Magn. Magn. Mater, 305, pp. 133-140, (2006); Lopez-Urias F, Torres-Heredia J J, Munoz-Sandoval E, J. Magn. Magn. Mater, 294, pp. e7-12, (2005); Donahue M J, Porter D G, OOMMF User's Guide, Version 1.0, (1999); Miltat J E, Donahue M J, Handbook of Magnetism and Advanced Magnetic Materials, 2, pp. 742-764, (2007); Kittel C, Rev. Mod. Phys, 21, pp. 541-583, (1949); Dennis C L, Et al., J. Phys. Condens. Matter, 14, pp. R1175-R1262, (2002); Piao H-G, Djuhana D, Shim J-H, Lee S-H, Jun S-H, Oh S K, Yu S-C, Kim D-H, J. Nanosci. Nanotechnol, 10, pp. 7212-7216, (2010); Djuhana D, Oktri D, Kurniawan C, Makara J. Sci, 22, pp. 198-204, (2018)","D. Djuhana; Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Depok, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","","IOP Publishing Ltd","Universitas Indonesia","4th International Symposium on Current Progress in Functional Materials, ISCPFM 2019","6 November 2019 through 7 November 2019","Bali","164362","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85096483378" +"Ender J.; Fiorentini S.; de Orio R.L.; Hadámek T.; Bendra M.; Goes W.; Selberherr S.; Sverdlov V.","Ender, Johannes (57211467647); Fiorentini, Simone (57211477066); de Orio, Roberto L. (55667231400); Hadámek, Tomáš (57321034300); Bendra, Mario (57320954500); Goes, Wolfgang (55884148500); Selberherr, Siegfried (8840302400); Sverdlov, Viktor (8908640600)","57211467647; 57211477066; 55667231400; 57321034300; 57320954500; 55884148500; 8840302400; 8908640600","Advances in Modeling Emerging Magnetoresistive Random Access Memories: From Finite Element Methods to Machine Learning Approaches","2022","Proceedings of SPIE - The International Society for Optical Engineering","12157","","1215708","","","","3","10.1117/12.2624595","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125671807&doi=10.1117%2f12.2624595&partnerID=40&md5=c00060acc30d26b04de14a4be1005089","Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Silvaco Europe, Cambridge, United Kingdom","Ender J., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria, Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Fiorentini S., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; de Orio R.L., Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Hadámek T., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Bendra M., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria, Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Goes W., Silvaco Europe, Cambridge, United Kingdom; Selberherr S., Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria; Sverdlov V., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria, Institute for Microelectronics, TU Wien, Gußhausstr. 27-29, Vienna, 1040, Austria","Emerging spin transfer torque magnetoresistive random access memories (STT MRAM) are nonvolatile and offer high speed and endurance. They are promising for stand-alone and embedded applications in the automotive industry, microcontrollers, Internet of Things, frame buffer memory, and slow SRAM. The MRAM cell usually includes a CoFeB fixed reference layer and a free magnetic layer (FL), separated by a tunnel barrier. To design ultra-scaled MRAM cells it is necessary to accurately model the torques acting on the magnetization in composite magnetic layers with one or several nonmagnetic inclusions between the ferromagnetic parts. The magnetization dynamics is governed by the Landau-Lifshitz-Gilbert (LLG) equation supplemented with the corresponding torques. The torques depend on nonequilibrium spin accumulation generated by an electric current. The electric current and the spin accumulation also depend on the magnetization. Therefore, the LLG and the spin-charge transport equations are coupled and must be solved simultaneously. We apply the finite element method (FEM) to numerically solve this coupled system of partial differential equations. To develop an open source solver, we use well-developed C++ FEM libraries. The computationally most expensive part is the demagnetizing field calculation. It is performed by a hybrid finite element-boundary element method. This confines the simulation domain for the field evaluation to the ferromagnets only. Advanced compression algorithms for large, dense matrices are used to optimize the performance of the demagnetizing field calculation in complex structures. To evaluate the torques acting on the magnetization, a coupled spin and charge transport approach is implemented. For the computation of the torques acting in a magnetic tunnel junction (MTJ), a magnetization-dependent resistivity of the tunnel barrier is introduced. A fully three-dimensional solution of the equations is performed to accurately model the torques acting on the magnetization. The use of a unique set of equations for the whole memory cell including the FL, fixed layer, contacts, and nonmagnetic spacers is one of the advantages of our approach. To incorporate the temperature increase due to the electric current, we solve the heat transport equation coupled to the electron, spin, and magnetization dynamics, and we demonstrate that the FL temperature is highly inhomogeneous due to a non-uniform magnetization of the FL during switching. Spin-orbit torque (SOT) MRAM is fast-switching and thus well suitable for caches. By means of micromagnetic simulations, we demonstrate the purely electrical switching of a perpendicular FL by the SOTs due to two orthogonal short current pulses. To further optimize the pulse sequence, a machine learning approach based on reinforcement learning is employed. Importantly, a neural network trained on a fixed material parameter set achieves switching for a wide range of material parameter variations. © 2022 SPIE.","Magnetoresistive random access memories; Spin-orbit torque MRAM; Spin-transfer torque MRAM","Automotive industry; C++ (programming language); Cobalt compounds; Domain walls; Ferromagnetic materials; Ferromagnetism; Finite element method; Iron compounds; Magnetic logic devices; Magnetic recording; Magnetization; Memory architecture; Spin dynamics; Static random access storage; Torque; Tunnel junctions; Demagnetizing field; Machine learning approaches; Magnetic layers; Magnetization dynamics; Spin orbits; Spin transfer torque; Spin-accumulations; Spin-orbit torque MRAM; Spin-transfer torque MRAM; Tunnel barrier; MRAM devices","","","","","Österreichische Nationalstiftung für Forschung, Technologie und Entwicklung; Christian Doppler Forschungsgesellschaft, CDG; Bundesministerium für Digitalisierung und Wirtschaftsstandort, BMDW","Financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association is gratefully acknowledged.","Ohno H., Stiles M.D., Dieny B., Spintronics, Proc. of the IEEE, 104, pp. 1782-1786, (2016); Iwasaki S., Perpendicular Magnetic Recording-Its Development and Realization, Proc. Jpn. Acad. Ser. B Phys. Biol. Sci, 85, pp. 37-54, (2009); Savtchenko L., Engel B., Rizzo N., Et al., Method of Writing to Scalable Magnetoresistance Random Access Memory Element, (2003); Sbiaa R., Meng H., Piramanayagam S.N., Materials with Perpendicular Magnetic Anisotropy for Magnetic Random Access Memory, Phys. Stat. Solidi (RRL) - Rapid Research Letters, 5, pp. 413-419, (2011); Slonczewski J.C., Current-driven Excitation of Magnetic Multilayers, J. Magn. Magn. Mater, 159, pp. L1-L7, (1996); Berger L., Emission of Spin Waves by a Magnetic Multilayer Traversed by a Current, Phys. Rev.B, 54, pp. 9353-9358, (1996); Apalkov D., Dieny B., Slaughter J.M., Magnetoresistive Random Access Memory, Proc. of the IEEE, 104, pp. 1796-1830, (2016); Chung S.-W., Kishi T., Park J.W., Et al., 4Gbit Density STT-MRAM Using Perpendicular MTJ Realized with Compact Cell Structure, Proc. International Electron Devices Meeting (IEDM), pp. 659-662, (2016); Song Y.J., Lee J.H., Shin H.C., Et al., Highly Functional and Reliable 8Mb STT-MRAM Embedded in 28nm Logic, Proc. International Electron Devices Meeting (IEDM), pp. 663-666, (2016); Sato H., Honjo H., Watanabe T., Et al., 14ns Write Speed 128Mb Density Embedded STT-MRAM with Endurance >1010 and 10yrs Retention @85°C Using Novel Low Damage MTJ Integration Process, Proc. International Electron Devices Meeting (IEDM), pp. 608-611, (2016); Golonzka O., Alzate J.-G., Arslan U., Et al., MRAM as Embedded Non-volatile Memory Solution for 22FFL FinFET Technology, Proc. International Electron Devices Meeting (IEDM), pp. 412-415, (2018); Miron I.M., Garello K., Gaudin G., Et al., Perpendicular Switching of a Single Ferromagnetic Layer Induced by In-plane Current Injection, Nature, 476, (2011); Liu L., Lee J., Gudmundsen T.J., Et al., Current-induced Switching of Perpendicularly Magnetized Magnetic Layers Using Spin Torque from the Spin Hall Effect, Phys. Rev. Lett, 109, (2012); Lee S.-W., Lee K.-J., Emerging Three-terminal Magnetic Memory Devices, Proc. of the IEEE, 104, pp. 1831-1843, (2016); Garello K., Yasin F., Couet S., Et al., SOT‐MRAM 300mm Integration for Low Power and Ultrafast Embedded Memories, Proc. VLSI Symp. Technology and Circuits, pp. C8-2, (2018); Fukami S., Anekawa T., Zhan C., Ohno H., A Spin-orbit Torque Switching Scheme with Collinear Magnetic Easy Axis and Current Configuration, Nature Nanotechnology, 11, pp. 621-625, (2016); Lau Y.-C., Betto D., Rode K., Et al., Spin-orbit Torque Switching without an External Field using Interlayer Exchange Coupling, Nature Nanotechnology, 11, pp. 758-762, (2016); Safeer C.K., Jue E., Lopez A., Et al., Spin-Orbit Torque Magnetization Switching Controlled by Geometry, Nature Nanotechnology, 11, pp. 143-146, (2015); Sverdlov V., Makarov A., Selberherr S., Two-pulse Sub-ns Switching Scheme for Advanced Spin-Orbit Torque MRAM, Solid-State Electronics, 155, pp. 49-56, (2019); Orio R.L., Ender J., Fiorentini S., Et al., Numerical Analysis of Deterministic Switching of a Perpendicularly Magnetized Spin-orbit Torque Memory Cell, IEEE J. Electron Devices Soc, 9, pp. 61-67, (2020); Fredkin D.R., Koehler T.R., Hybrid Method for Computing Demagnetizing Fields, IEEE Transactions on Magnetics, 26, 2, pp. 415-417, (1990); Popovic N., Praetorius D., Applications of H-Matrix Techniques in Micromagnetics, Computing, 74, 3, pp. 177-204, (2005); Kolev T., Dobrev V., MFEM: Modular Finite Element Methods Library, (2010); Albrecht N., Borst C., Boysen D., Et al., H2Lib, (2016); Abert C., Exl L., Selke G., Numerical Methods for the Stray-Field Calculation: A Comparison of Recently Developed Algorithms, Journal of Magnetism and Magnetic Materials, 326, pp. 176-185, (2013); Abert C., Ruggeri M., Bruckner F., Et al., A Three-dimensional Spin-diffusion Model for Micromagnetics, Scientific Reports, 5, (2015); Lepadatu S., Unified Treatment of Spin Torques Using a Coupled Magnetisation Dynamics and Three-dimensional Spin Current Solver, Scientific Reports, 7, (2017); Fiorentini S., Ender J., Selberherr S., Et al., Coupled Spin and Charge Drift-Diffusion Approach Applied to Magnetic Tunnel Junctions, Solid-State Electronics, 186, (2021); Prejbeanu I.L., Kerekes M., Sousa R.C., Et al., Thermally assisted MRAM, Journal of Physics: Condensed Matter, 19, 16, (2007); Hadamek T., Selberherr S., Goes W., Sverdlov V., Heating Asymmetry in Magnetoresistive Random Access Memories, Proceedings of the World Multi-Conference on Systemics, Cybernetics and Informatics (WMSCI), pp. 63-66, (2021); Sutton R.S., Barto A.G., Reinforcement Learning: An Introduction, (1998); Silver D., Hubert T., Schrittwieser J., Et al., A General Reinforcement Learning Algorithm that Masters Chess, Shogi, and Go through Self-play, Science, 362, 6419, pp. 1140-1144, (2018); Orio R.L., Ender J., Fiorentini S., Et al., Optimization of a Spin-Orbit Torque Switching Scheme Based on Micromagnetic Simulations and Reinforcement Learning, Micromachines, 12, (2021); Makarov A., Modeling of Emerging Resistive Switching Based Memory Cells, (2014)","J. Ender; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Ender@iue.tuwien.ac.at; S. Fiorentini; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Fiorentini@iue.tuwien.ac.at; R.L. de Orio; Institute for Microelectronics, TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Orio@iue.tuwien.ac.at; T. Hadámek; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Hadamek@iue.tuwien.ac.at; M. Bendra; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Bendra@iue.tuwien.ac.at; S. Selberherr; Institute for Microelectronics, TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Selberherr@iue.tuwien.ac.at; V. Sverdlov; Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, The TU Wien, Vienna, Gußhausstr. 27-29, 1040, Austria; email: Sverdlov@iue.tuwien.ac.at","Lukichev V.F.; Rudenko K.V.","SPIE","JSC Molecular Electronics Research Institute; NIX Company; TechnoInfo Ltd.","14th International Conference on Micro- and Nano-Electronics 2021, ICMNE 2021","4 October 2021 through 8 October 2021","Zvenigorod","177281","0277786X","978-151065190-6","PSISD","","English","Proc SPIE Int Soc Opt Eng","Conference paper","Final","","Scopus","2-s2.0-85125671807" +"Zhao Z.; Garraud N.; Arnold D.P.; Rinaldi C.","Zhao, Zhiyuan (57197844470); Garraud, Nicolas (25723206600); Arnold, David P (8971174200); Rinaldi, Carlos (36524654200)","57197844470; 25723206600; 8971174200; 36524654200","Effects of particle diameter and magnetocrystalline anisotropy on magnetic relaxation and magnetic particle imaging performance of magnetic nanoparticles","2020","Physics in Medicine and Biology","65","2","025014","","","","23","10.1088/1361-6560/ab5b83","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85078512403&doi=10.1088%2f1361-6560%2fab5b83&partnerID=40&md5=11b149fd25a961600800ff62893fc774","Department of Chemical Engineering, University of Florida, Gainesville, 32611, FL, United States; Department of Electrical and Computer Engineering, University of Florida, Gainesville, 32611, FL, United States; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, 32611, FL, United States","Zhao Z., Department of Chemical Engineering, University of Florida, Gainesville, 32611, FL, United States; Garraud N., Department of Electrical and Computer Engineering, University of Florida, Gainesville, 32611, FL, United States; Arnold D.P., Department of Electrical and Computer Engineering, University of Florida, Gainesville, 32611, FL, United States; Rinaldi C., Department of Chemical Engineering, University of Florida, Gainesville, 32611, FL, United States, J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, 32611, FL, United States","The dynamic magnetization of immobilized spherical single-domain magnetic nanoparticles (MNPs) with uniaxial or cubic magnetocrystalline anisotropy was studied computationally by executing simulations based on the Landau-Lifshitz-Gilbert (LLG) equation. For situations when a static magnetic field was suddenly applied and then removed, the effects of particle diameter and anisotropy (considering both type of symmetry and characteristic energy) on the characteristic magnetic relaxation time were studied parametrically. The results, for both anisotropy symmetries, show that when a static magnetic field is suddenly turned on or off the MNPs undergo a successive two-step or combined one-step relaxation. Whether a MNP relaxes with one or two steps when the field is turned on is determined by the competition between the energy of the applied magnetic field, the magnetic anisotropy energy, and thermal energy. When the applied magnetic field is suddenly turned off, our results show good agreement with theoretical predictions for the cases of and, where represents the magnetic anisotropy energy barrier, is the Boltzmann constant and represents the absolute temperature. For the case of an applied alternating magnetic field (AMF) that is typical of magnetic particle imaging (MPI) applications, the effects of particle diameter and anisotropy symmetry were studied in terms of time-domain magnetization dynamics, dynamic hysteresis loops, harmonic spectra, and x-space point spread functions (PSFs). Results illustrate that the type of magnetocrystalline anisotropy (uniaxial versus cubic) has a significant effect on the MPI performance of the nanoparticles. These computational studies provide insight into the role of particle diameter and magnetic anisotropy on the performance of MNPs for applications in magnetorelaxometry and MPI. © 2020 Institute of Physics and Engineering in Medicine.","","Anisotropy; Hot Temperature; Magnetic Fields; Magnetite Nanoparticles; Tomography; Magnetic anisotropy; Magnetic bubbles; Magnetic field effects; Magnetic materials; Magnetic relaxation; Magnetization; Magnetocrystalline anisotropy; Optical transfer function; Particle size; magnetite nanoparticle; Alternating magnetic field; Applied magnetic fields; Dynamic hysteresis loops; Landau-Lifshitz-Gilbert equations; Magnetic anisotropy energy; Magnetic nanoparti cles (MNPs); Magnetic particle imaging; Static magnetic fields; anisotropy; chemistry; heat; magnetic field; procedures; tomography; Magnetic nanoparticles","","Magnetite Nanoparticles, ","","","","","Aharoni A., Relaxation-time of superparamagnetic particles with cubic anisotropy, Phys. 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Surg., 8, (2018); Wegner F., Buzug T.M., Barkhausen J., Take a deep breath-monitoring of inhaled nanoparticles with magnetic particle imaging, Theranostics, 8, pp. 3691-3692, (2018); Weizenecker J., Gleich B., Rahmer J., Borgert J., Micro-magnetic simulation study on the magnetic particle imaging performance of anisotropic mono-domain particles, Phys. Med. Biol., 57, 22, pp. 7317-7327, (2012); Wu K., Su D.Q., Saha R., Liu J.M., Wang J.P., Investigating the effect of magnetic dipole-dipole interaction on magnetic particle spectroscopy: implications for magnetic nanoparticle-based bioassays and magnetic particle imaging, J. Phys. D: Appl. Phys., 52, 33, (2019); Yu E.Y., Et al., Magnetic particle imaging for highly sensitive, quantitative, and safe in vivo gut bleed detection in a murine model, ACS Nano, 11, pp. 12067-12076, (2017); Yu E.Y., Bishop M.I., Zheng B., Ferguson R.M., Khandhar A.P., Kemp S.J., Krishnan K.M., Goodwill P.W., Conolly S.M., Magnetic particle imaging: a novel in vivo imaging platform for cancer detection, Nano Lett., 17, pp. 1648-1654, (2017)","C. Rinaldi; Department of Chemical Engineering, University of Florida, Gainesville, 32611, United States; email: carlos.rinaldi@ufl.edu","","Institute of Physics Publishing","","","","","","00319155","","PHMBA","31766030","English","Phys. Med. Biol.","Article","Final","","Scopus","2-s2.0-85078512403" +"Chen J.; Du R.; Ma Z.; Sun Z.; Zhang L.","Chen, Jingrun (57219146828); Du, Rui (56763448500); Ma, Zetao (57222112538); Sun, Zhiwei (57219501555); Zhang, Lei (56364393800)","57219146828; 56763448500; 57222112538; 57219501555; 56364393800","ON THE MULTISCALE LANDAU–LIFSHITZ–GILBERT EQUATION: TWO-SCALE CONVERGENCE AND STABILITY ANALYSIS","2022","Multiscale Modeling and Simulation","20","2","","835","856","21","1","10.1137/21M1438177","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85133518359&doi=10.1137%2f21M1438177&partnerID=40&md5=797f49998ac8e06bdd55c3281e557da3","School of Mathematical Sciences, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China; Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; School of Mathematical Sciences, Institute of Natural Sciences, MOE-LSC, Shanghai Jiao Tong University, Shanghai, 200240, China","Chen J., School of Mathematical Sciences, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China, School of Mathematical Sciences, University of Science and Technology of China, Anhui, Hefei, 230026, China, Suzhou Institute for Advanced Research, University of Science and Technology of China, Jiangsu, Suzhou, 215123, China; Du R., School of Mathematical Sciences, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, 215006, China; Ma Z., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Sun Z., School of Mathematical Sciences, Soochow University, Suzhou, 215006, China; Zhang L., School of Mathematical Sciences, Institute of Natural Sciences, MOE-LSC, Shanghai Jiao Tong University, Shanghai, 200240, China","Permalloy is a nickel-iron magnetic alloy, which typically has a face-centered cubic phase but may form an irregular polycrystalline structure. Its magnetization dynamics is modeled by the multiscale Landau–Lifshitz–Gilbert (LLG) equation with locally periodic material coefficients. We consider homogenization of the multiscale LLG equation in this work, and the novelty lies in three aspects. First, we derive the homogenized LLG equation using the formal asymptotic expansion and prove the rigorous convergence using the notion of two-scale convergence. Second, we establish a stability result of the homogenized LLG equation under small disturbances of material coefficients. Third, a modified Gauss–Seidel projection method is implemented to verify the convergence between the multiscale and homogenized LLG equations and the stability result. © 2022 Society for Industrial and Applied Mathematics.","Gauss–Seidel projection method; multiscale Landau–Lifshitz–Gilbert equation; stability analysis; two-scale convergence","Iron alloys; Stability; Convergence and stability analysis; Gauss-Seidel; Gauss–seidel projection method; Landau-Lifshitz-Gilbert equations; Material coefficients; Multiscale landau–lifshitz–gilbert equation; Projection method; Stability analyze; Stability results; Two scale convergence; Nickel alloys","","","","","Postgraduate Research & Practice Innovation Program of Jiangsu Province, (11861131004, 11871339, KYCX21 2934); National Natural Science Foundation of China, NSFC, (11501399, 11971021)","∗Received by the editors August 2, 2021; accepted for publication (in revised form) March 25, 2022; published electronically June 30, 2022. https://doi.org/10.1137/21M1438177 Funding: The work of the first author was supported by the National Natural Science Foundation of China (NSFC) grant 11971021. The work of the second author was supported by NSFC grant 11501399. The work of the fourth author was supported by the Postgraduate Research & Practice Innovation Program of Jiangsu Province grant KYCX21 2934. The work of the fifth author was partially supported by NSFC grants 11871339 and 11861131004.","Acerbi E., ChiadoPiat V., Dal Maso G., Percivale D., An extension theorem from connected sets, and homogenization in general periodic domains, Nonlinear Anal. Theory Methods Appl, 18, pp. 481-496, (1992); Allaire G., Homogenization and two-scale convergence, SIAM J. Math. Anal, 23, pp. 1482-1518, (1992); Alouges F., Bouard A. D., Merlet B., Nicolas L., Stochastic homogenization of the Landau-Lifshitz-Gilbert equation, Stoch. Partial Differ. Equ. Anal. Comput, 9, pp. 789-818, (2021); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal. 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J., Numerical micromagnetics: a review, Boletín de la Sociedad Española de Matemática Aplicada, SeMA, 39, pp. 103-135, (2007); Garcia-Cervera C. J., Improved Gauss-Seidel projection method for micromagnetics simulations, IEEE Trans. Magnetics, 39, pp. 1766-1770, (2003); Gilbert T. L., A Lagrangian formulation of the gyromagnetic equation of the magnetization field, Phys. Rev, 100, (1955); Hamdache K., Tilioua M., On the zero thickness limit of thin ferromagnetic films with surface anisotropy energy, Math. Models Methods Appl. Sci, 11, pp. 1469-1490, (2001); Kourounis D., Fuchs A., Schenk O., Towards the next generation of multiperiod optimal power flow solvers, IEEE Trans. Power Syst, 33, pp. 1-10, (2018); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); Landau L. D., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. 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Simul.","Article","Final","","Scopus","2-s2.0-85133518359" +"Cui Y.; Luo J.","Cui, Yan (57201126705); Luo, Jun (57139122100)","57201126705; 57139122100","Spin-Transfer Torque Materials and Devices for Magnetic Random-Access Memory (STT-MRAM)","2022","Spintronics: Materials, Devices, and Applications","","","","93","111","18","1","10.1002/9781119698968.ch4","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85147190567&doi=10.1002%2f9781119698968.ch4&partnerID=40&md5=6993c166da20e946ff3d1de3479cd71e","Key Laboratory of Microelectronic Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, China","Cui Y., Key Laboratory of Microelectronic Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, China; Luo J., Key Laboratory of Microelectronic Devices and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, China","This chapter briefly describes the development history of MRAM, explains the flip mechanism and flip conditions of STT-MRAM from the perspective of the LLG equation, and further extends to the electrical and magnetic properties of MRAM. Then the manufacturing process related to MRAM is described, including but not limited to photolithography, etching, dielectric isolation, contact, passivation and testing technologies. Finally, the development status of STT-MRAM is given as a guideline for IC designers working on MRAM. © 2022 John Wiley & Sons Ltd. All rights reserved.","Integration process; LLG function; Magnetic anisotropy; STT-MRAM; TMR","","","","","","","","Berger L., Low-field magnetoresistance and domain drag in ferromagnets, J. Appl. Phys, 49, 3, pp. 2156-2161, (1978); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, 1-2, pp. L1-L7, (1996); Myers E.B., Ralph D.C., Katine J.A., Louie R.N., Buhrman R.A., Current-Induced Switching of Domains in Magnetic Multilayer Devices, Science, 285, 5429, pp. 867-870, (1999); Zhang S., Levy P., Fert A., Mechanisms of Spin-Polarized Current-Driven Magnetization Switching, Phys. Rev. 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Today, 17, (2014); Diao Z., Panchula A., Ding Y., Pakala M., Wang S., Li Z., Apalkov D., Nagai H., Driskill-Smith A., Wang L.-C., Chen E., Huai Y., Spin transfer switching in dual MgO magnetic tunnel junctions, Appl. Phys. Lett, 90, (2007); Hu G., Lee J.H., Nowak J.J., Sun J.Z., Harms J., Annunziata A., Brown S., Chen W., Kim Y.H., Lauer G., Liu L., Marchack N., Murthy S., O'Sullivan E.J., Park J.H., Reuter M., Robertazzi R.P., Trouilloud P.L., Zhu Y., Worledge D.C., STT-MRAM with double magnetic tunnel junctions, (2015); Liu H., Honda Y., Taira T., Matsuda K.I., Arita M., Uemura T., Et al., Comment on ""Water-driven programmable polyurethane shape memory polymer: Demonstration and mechanism., Appl Phys. Lett, 101, 13, pp. 1488-1489, (2012); Lu H., Liu Y., Leng J., Du S., Magnetization switching by spin-torque effect in off-aligned structure with perpendicular anisotropy, Appl. Phys. Lett, 97, 5, (2010); Sbiaa R., Piramanayagam S.N., Liew T., High speed in spin-torque-based magnetic memory using magnetic nanocontacts, Phys. Status Solidi, 7, (2013); Sbiaa R., Magnetization switching by spin-torque effect in off-aligned structure with perpendicular anisotropy, J. Phys. D: Appl. Phys, 46, (2013); Kambersky V., Spin-orbital Gilbert damping in common magnetic metals, Phys. Rev. B, 76, (2007); Fahnle M., Illg C., Electron theory of fast and ultrafast dissipative magnetization dynamics, J. Phys.: Condens. Matter, 23, (2011); Mizukami S., Et al., J. Appl. Phys, 105, (2009); Lenz K., Wende H., Kuch W., Baberschke K., Nagy K., Janossy A., Two-magnon scattering and viscous Gilbert damping in ultrathin ferromagnets, Phys. Rev. B, 73, (2006); Lagae L., Wirix-Speetjens R., Eyckmans W., Borghs S., de Boeck J., Increased Gilbert damping in spin valves and magnetic tunnel junctions, J. Magn. Magn. Mater, 286, (2005); Smith N., Arnett P., White-noise magnetization fluctuations in magnetoresistive heads, Appl. Phys. Lett, 78, (2001); Djayaprawira D.D., Tsunekawa K., Nagai M., Maehara H., Yamagata S., Watanabe N., 230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions, Applied Physics Letters 2005, 86, 9, (2005); Piramanayagam S.N., Sbiaa R., Tahmasebi T., Magnetoresistance device and memory device including the magnetoresistance device, (2012); Ma Q., Et al., Sci. Rep, (2015); Bai Z., Shen L., Han G., Feng Y.P., Data Storage: Review of Heusler Compounds Spin, 2, 4, (2012); Chumak A., Serga A.A., Hillebrands B., Magnon spintronics, Nat. Phys, 11, (2015); Husain S., Akansel S., Kumar A., Svedlindh A.P., Chaudhary S., Sci. Rep, (2016); Galanakis I., Dederichs H., Half-metallicity and Slater-Pauling behavior in the ferromagnetic Heusler alloys, Half-metallic Alloys, (2005); Hirohata A., Kikuchi M., Tezuka N., Inomata K., Claydon J.S., Xu Y.B., Et al., Heusler alloy/semiconductor hybrid structures, Curr. Opin. Solid State Mater. Sci, 10, (2006); Sato J., Oogane M., Naganuma H., Ando Y., Large Magnetoresistance Effect in Epitaxial Co2Fe0.4Mn0.6Si/Ag/Co2Fe0.4Mn0.6Si Devices, Appl. Phys. Express, 4, (2011); Tezuka N., Ikeda N., Mitsuhashi F., Sugimoto S., Improved tunnel magnetoresistance of magnetic tunnel junctions with heusler co2FeAl0.5Si0.5 electrodes fabricated by molecular beam epitaxy, Appl. Phys. Lett, 94, (2009); Hirohata A., Sukegawa H., Yanagihara H., Zutic I., Seki T., Mizukami S., Et al., Roadmap for Emerging Materials for Spintronic Device Applications, IEEE Trans. Magn, 51, (2015); Akerman J., Brown P., DeHerrera M., Durlam M., Fuchs E., Gajewski D., Et al., Demonstrated reliability of 4-mb MRAM, IEEE Trans. Device Mater. Reliab, 4, (2004); Zhao W., Zhang Y., Devolder T., Klein J.O., Ravelosona D., Chappert C., Et al., Failure and reliability analysis of STT-MRAM, Microelectron. Reliab, 52, (2012); Xiangyu D., Xiaoxia W., Guangyu S., Yuan X., Li H., Yiran C., Circuit and microarchitecture evaluation of 3D stacking magnetic RAM (MRAM) as a universal memory replacement, (2008); Sun G., Dong X., Xie Y., Li J., Chen Y., A novel architecture of the 3D stacked MRAM L2 cache for CMPs, IEEE 15th International Symposium on High Performance Computer Architecture, (2009); Faber L., Zhao W., Klein J., Devolder T., Chappert C., Dynamic compact model of Spin-Transfer Torque based Magnetic Tunnel Junction (MTJ), 4th International Conference on Design & Technology of Integrated Systems in Nanoscale Era, (2009); Panagopoulos G., Augustine C., Roy K., 28-nm 0.08 mm2/Mb Embedded MRAM for Frame Buffer Memory, (2011); Han S.H., Lee J.M., Shin H.M., Lee J.H., Suh K.S., Nam K.T., Et al., Electron Devices Meeting (IEDM), (2020); Naik V.B., Yamane K., Lee T.Y., Kwon J., Chao R., Lim J.H., Chung N.L., Behin-Aein B., Hau L.Y., Zeng D., Otani Y., Chiang C., Huang Y., Pu L., Jang S.H., Neo W.P., Dixit H., Goh S.K.L.C., Toh E.H., Ling T., Hwang J., Ting J.W., Low R., Zhang L., Lee C.G., Balasankaran N., Tan F., Gan K.W., Yoon H., Congedo G., Mueller J., Pfefferling B., Kallensee O., Vogel A., Kriegerstein V., Merbeth T., Seet C.S., Ong S., Xu J., Wong J., You Y.S., Woo S.T., Chan T.H., Quek E., Siah S.Y., JEDEC-Qualified Highly Reliable 22nm FD-SOI Embedded MRAM For Low-Power Industrial-Grade, and Extended Performance Towards Automotive-Grade-1 Applications, (2020); Shih Y.C., Lee C.F., Chang Y.A., Lee P.H., Lin H.J., Chen Y.L., Lo C.P., Lin K.F., Chiang T.W., Lee Y.J., Shen K.H., Wang R., Wang W., Chuang H., Wang E., Chih Y.D., Chang J., A Reflow-capable, Embedded 8Mb STT-MRAM Macro with 9nS Read Access Time in 16nm FinFET Logic CMOS Process, (2020); Edelstein D., Rizzolo M., Sil D., Dutta A., DeBrosse J., Wordeman M., Et al., A 14 nm Embedded STT-MRAM CMOS Technology, (2020)","","","wiley","","","","","","","978-111969896-8; 978-111969897-5","","","English","Spintronics: Materials, Dev., and Applic.","Book chapter","Final","","Scopus","2-s2.0-85147190567" +"Mustaghfiroh Q.; Djuhana D.; Kurniawan C.","Mustaghfiroh, Q. (57212169560); Djuhana, D. (26027849100); Kurniawan, C. (55600299500)","57212169560; 26027849100; 55600299500","Hysteresis observation of CoFe and CoFeB model disk using micromagnetic simulation","2020","IOP Conference Series: Materials Science and Engineering","763","1","012073","","","","1","10.1088/1757-899X/763/1/012073","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85084289833&doi=10.1088%2f1757-899X%2f763%2f1%2f012073&partnerID=40&md5=1a030b2aac03603c61499ed50ca53787","Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Gedung 440-442 Kawasan Puspiptek Serpong, Banten, 15314, Indonesia","Mustaghfiroh Q., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; Djuhana D., Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; Kurniawan C., Research Center for Physics, Indonesian Institute of Sciences (LIPI), Gedung 440-442 Kawasan Puspiptek Serpong, Banten, 15314, Indonesia","In this work, hysteresis loop of CoFe and CoFeB disk ferromagnets are observed by using micromagnetic simulation OOMMF based on LLG equation. The diameter varied from 50-500 nm with the thickness 5 nm and 10 nm. For simulation process, the damping factor of 0.05 and the cell size 2.5 × 2.5 × 2.5 nm3 were fixed. We applied parallel and perpendicular external field to generate hysteresis loop of CoFe and CoFeB disk ferromagnets. Interestingly, we found two behaviours of coercivity, first less than diameter 100 nm and second, greater than 100 nm. For parallel-applied field of CoFe and CoFeB, the coercivity showed fluctuation around 20-160 mT. Greater than diameter 100 nm, the coercivity in a constant value around 40 mT for CoFe and around 20 mT for CoFeB. For perpendicular applied field of CoFe, we still observed the coercivity around 40 mT but greater than 100 nm, the coercivity dropped to zero. For CoFeB with perpendicular applied field, the coercivity decrease as the diameter increase until reach diameter 100 nm. Greater than the diameter 100 nm, the coercivity is constant at 20 mT. According to the results, we had observed the Perpendicular Magnetic Anisotropy (PMA) behaviour in both CoFe and CoFeB disk ferromagnets with certain value of the coercivity when the field applied in perpendicular direction. © 2020 Published under licence by IOP Publishing Ltd.","","","","","","","Universitas Indonesia, UI","Ac k n o wle d g e m e n ts The authors would like to thank Universitas Indonesia for funding this research through PITTA Grant Universitas Indonesia with contract number 2245/UN2.R3.1/HKP.05.00/2018 Re fe re n c e s [1] SundarRS andDeeviS C2005Int.Mater.Rev.50157–92 [2] Meo A, Chureemart P, Wang S, Chepulskyy R, Apalkov D, Chantrell R W and Evans R F L 2017 Sci. Rep. 7 16729 [3] GubinSP,KoksharovYA,KhomutovG BandYurkovG Y2005Russ.Chem.Rev.74 489 [4] CaiG,WuZ,GuoF,WuY,LiH,LiuQ,FuM,ChenTandKangJ2015NanoscaleRes.Lett. 10 126 [5] NegusseE,LussierA,DvorakJandIdzerdaYU 2007Appl.Phys.Lett.90092502 [6] HanX,MaJ,WangZ,ZuoYandXiL2014ActaMetall.27 1099–104 [7] Chaves-O’FlynnG D,WolfG,PinnaD andKentAD 2015J.Appl.Phys.117 170705 [8] DonahueMJandPorterD G 1999OOMMFUser’sGuide,Version1.0(Gaithersburg:National Institute of Standards and Technology) [9] PiaoHG,ChoiHC,ShimJH,KimDHandYouCY 2011 Appl.Phys.Lett.99 192512 [10]CoeyJMD2010MagnetismandMagneticMaterials(New York: CambridgenUievrsitrPeys) [11] Tekgül A, Alper M, Kockar H and Haciismailoglu M 2015 J. Mater. Sci. Mater. Electron. 26 2411–7 [12] Ngo D T, Quach D T, Tran Q H, Møhave K, Phan T L and Kim D H 2014 J. Phys. D: Appl. Phys. 47 445001 [13] Mukherjee P K 2016 J. Applicable Chem. 5 714–8 [14]KittelC2005IntroductiontoSolidStatePhysics8thed(Hoboken: John Wileynad","Sundar R.S., Deevi S.C., Int. Mater. Rev., 50, 3, pp. 157-192, (2005); Meo A., Chureemart P., Wang S., Chepulskyy R., Apalkov D., Chantrell R.W., Evans R.F.L., Sci. Rep., 7, 1, (2016); Gubin S.P., Koksharov Y.A., Khomutov G.B., Yurkov G.Y., Russ. Chem. Rev., 74, 6, (2005); Cai G., Wu Z., Guo F., Wu Y., Li H., Liu Q., Fu M., Chen T., Kang J., Nanoscale Res. Lett., 10, 1, (2015); Negusse E., Lussier A., Dvorak J., Idzerda Y.U., Appl. Phys. Lett., 90, (2007); Han X., Ma J., Wang Z., Zuo Y., Xi L., Acta Metall, 27, 6, pp. 1099-1104, (2014); Chaves-O'Flynn G.D., Wolf G., Pinna D., Kent A.D., J. Appl. Phys., 117, (2015); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 1.0, (1999); Piao H.G., Choi H.C., Shim J.H., Kim D.H., You C.Y., Appl. Phys. Lett., 99, (2011); Coey J.M.D., Magnetism and Magnetic Materials, (2010); Tekgul A., Alper M., Kockar H., Haciismailoglu M., J. Mater. Sci. Mater. Electron, 26, 4, pp. 2411-2417, (2015); Ngo D.T., Quach D.T., Tran Q.H., Mohave K., Phan T.L., Kim D.H., J. Phys. D: Appl. Phys., 47, (2014); Mukherjee P.K., J. Applicable Chem., 5, pp. 714-718, (2016); Kittel C., Introduction to Solid State Physics, (2005)","D. Djuhana; Department of Physics, Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Indonesia, Kampus UI Depok, Depok, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","Anggraningrum I.T.; Triyono D.; Lee Y.-I.; Mulyana Y.; Handoko A.D.","Institute of Physics Publishing","Universitas Indonesia","3rd International Symposium on Current Progress in Functional Materials 2018, ISCPFM 2018","8 August 2018 through 9 August 2018","Depok","159473","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85084289833" +"Wang W.; Du A.","Wang, Wang (57211349477); Du, An (7006264005)","57211349477; 7006264005","Simulation of the AC susceptibility for nano-ferromagnetic materials","2019","Materials Research Express","6","11","116114","","","","4","10.1088/2053-1591/ab488c","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85073625395&doi=10.1088%2f2053-1591%2fab488c&partnerID=40&md5=05471896b42b8ab56edc7f9964acc7fc","College of Science, Northeastern University, Shenyang, 110819, China","Wang W., College of Science, Northeastern University, Shenyang, 110819, China; Du A., College of Science, Northeastern University, Shenyang, 110819, China","In this paper, the AC susceptibility of non-interacting random oriented nano-magnetic materials is studied by means of Landau-Lifshitz-Gilbert (LLG) equation, and temperature influence on the susceptibility are considered by introducing random fields. The results show that the AC susceptibility presents resonance behaviors in the alternating field. As the temperature increases, the resonance frequency of the system decreases monotonously. When the amplitude(H 0) of the alternating field is small (H 0 ≤ 0.02 Hr, where Hr is the resonance magnetic field in uniform reversal model), the resonance frequency is basically unchanged, however, when the amplitude of the alternating field is big (H 0 > 0.02 Hr ), the resonance frequency decreases significantly as H 0 increases. For different damping parameters, when the amplitude of alternating field is small, the amplitude of AC susceptibility decreases with the increase of damping parameters, but the resonance frequency changes little. When the amplitude of alternating field is big, the imaginary part of AC susceptibility and resonance frequency no longer change monotonously with the damping parameters. Based on the above results, we analyzed some experimental results of AC susceptibility of absorbing nanomaterials. © 2019 IOP Publishing Ltd.","ACsusceptibility; Landau-Lifshitz-Gilbert (LLG) equation; nano-ferromagnetic materials","Damping; Ferromagnetic materials; Ferromagnetism; Natural frequencies; Ac susceptibility; Damping parameters; Imaginary parts; Landau-Lifshitz-Gilbert equations; Resonance frequencies; Resonance-magnetic; Temperature increase; Temperature influence; Magnetic susceptibility","","","","","","","Lisjak D., Mertelj A., Anisotropic magnetic nanoparticles: A review of their properties, syntheses and potential application, Prog. Mater Sci., 95, pp. 286-328, (2018); Ha J.K., Hertel R.H., Kirschner J., Micromagnetic study of magnetic configurations in submicron permalloy disks, Phys. Rev., 67, (2003); Mistral Q., Kampen M., Hrkac G., Kim J.V., Devolder T., Crozat P., Chappert C., Lagae L., Schrefl T., Current-driven vortex oscillations in metallic nanocontacts, Phys. Rev. Lett., 100, (2008); Guslienko K.Y., Scholz W., Chantrell R.W., Novosad V., Vortex-state oscillations in soft magnetic cylindrical dots, Phys. Rev., 71, (2005); Chubykalo-Fesenko O., Nowak U., Chantrell R.W., Garanin D., Dynamic approach for micromagnetics close to the Curie temperature, Phys. Rev., 74, (2006); Okano G., Nozaki Y., Evaluation of the effective potential barrier height in nonlinear magnetization dynamics excited by ac magnetic field, Phys. Rev., 97, (2018); Zhu J.G., Thermal magnetic noise and spectra in spin valve heads, J. Appl. Phys., 91, pp. 7273-7275, (2002); Boerner E.D., Bertram H.N., Dynamic of thermally activated reversal in nonuniformly magnetized single particles, IEEE Trans. Magn., 33, pp. 3052-3054, (1997); Mitsumata C., Tomita S., Seki T., Mizuguchi M., Simple analysis for frequency increase in spin torque oscillation, IEEE Trans. Magn., 48, pp. 3955-3957, (2012); Wei D., Song J., Liu C., Micromagnetics at finite temperature, IEEE Trans. Magn., 52, (2016); Song J.J., Wang J., Wei D., Hono K., Micromagnetic studies at finite temperature on FePt-C granular films, IEEE Trans. Magn., 53, (2017); Wang D.W., Weerasinghe J., Bellaiche L., Atomistic molecular dynamic simulations of multiferroics, Phys. Rev. Lett., 109, (2012); Nishino M., Miyashita S., Realization of the thermal equilibrium in inhomogeneous magnetic systems by the Landau-Lifshitz-Gilbert equation with stochastic noise, and its dynamical aspects, Phys. Rev., 91, (2015); Alkadour B., Mercer J.I., Whitehead J.P., Southern B.W., Surface vacancy mediated pinning of the magnetization in γ-Fe2O3 nanoparticles: A micromagnetic simulation study, Phys. Rev., 93, (2016); Hinzke D., Atxitia U., Carva K., Nieves P., Chubykalo-Fesenko O., Oppeneer P.M., Nowak U., Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys, Phys. Rev., 92, (2015); Picco M., Felix R., Dynamical ac study of the critical behavior in Heisenberg spin glasses, Phys. Rev., 71, (2005); Wang H., Dai Y.Y., Gong W.J., Geng D.Y., Ma S., Li D., Liu W., Zhang Z.D., Broadband microwave absorption of CoNi@C nanocapsules enhanced by dual dielectric relaxation and multiple magnetic resonances, Appl. Phys. Lett., 102, (2013); Zhang Q., Li C.F., Chen Y.N., Han Z., Wang H., Wang Z.J., Geng D.Y., Liu W., Zhang Z.D., Effect of metal grain size on multiple microwave resonances of Fe/TiO2 metal-semiconductor composite, Appl. Phys. Lett., 97, (2010); Luo J.H., Shen P., Yao W., Jiang C.F., Xu J.G., Synthesis, characterization, and microwave absorption properties of reduced graphene oxide/strontium ferrite/polyaniline nanocomposites, Nanoscale Res. Lett., 11, (2016); Xu F., Zhang X.Y., Phuoc N.N., Ma Y.G., Ong C.K., High-frequency permeability spectra of FeCoSiN/Al2O3 laminated films: Tuning of damping by magnetic couplings dependent on the thickness of each ferromagnetic layer, J. Appl. Phys., 105, (2009); Youssel J.B., Nrosseau C., Magnetization damping in two-component metal oxide micropowder and nanopowder compacts by broaddand ferromagnetic resonance measurements, Phys. Rev., 74, (2006); Choi M., Lee S., Kim J., Clustering effect on the frequency-dependent magnetic properties of Fe-Co micro hollow fiber composites, IEEE Trans. Magn., 53, (2017); Deutsch J.M., Mai T., Narayan O., Hysteresis multicycles in nanomagnet arrays, Phys. Rev., 71, (2005); Iglesias O., Labarta A., Batlle X., Exchange bias phenomenology and models of core/shell nanoparticles, J. Nanosci. Nanotechnol., 8, pp. 2761-2780, (2008); Jin M.H., Zheng B., Xiong L., Zhou N.J., Wang L., Numerical simulations of critical dynamics in anisotropic magnetic films with the stochastic Landau-Lifshitz-Gilbert equation, Phys. Rev., 98, (2018); Li Y.B., Yi R., Yan A.G., Deng L.W., Zhou K.C., Liu X.H., Facile synthesis and properties of ZnFe2O4 and ZnFe2O4/polypyrrole core-shell nanoparticles, Solid State Sci., 11, pp. 1319-1324, (2009); Liu J., Feng Y.B., Qiu T., Synthesis, characterization, and microwave absorption properties of Fe-40 wt%Ni alloy prepared by mechanical alloying and annealing, J. Magn. Magn. Mater., 323, pp. 3071-3076, (2011); Li L.C., Chen K.Y., Liu H., Tong G.X., Qian H.S., Hao B., Attractive microwave-absorbing properties of M-BaFe12O19 ferrite, J. Alloys Compd., 557, pp. 11-17, (2013)","","","Institute of Physics Publishing","","","","","","20531591","","","","English","Mater. Res. Express","Article","Final","","Scopus","2-s2.0-85073625395" +"Miyashita S.; Nishino M.; Toga Y.; Hinokihara T.; Uysal I.E.; Miyake T.; Akai H.; Hirosawa S.; Sakuma A.","Miyashita, Seiji (7102333760); Nishino, Masamichi (7103009415); Toga, Yuta (26532037600); Hinokihara, Taichi (55329793900); Uysal, Ismail Enes (56441165200); Miyake, Takashi (7202951411); Akai, Hisazumi (7004859390); Hirosawa, Satoshi (7103189702); Sakuma, Akimasa (7102719646)","7102333760; 7103009415; 26532037600; 55329793900; 56441165200; 7202951411; 7004859390; 7103189702; 7102719646","Atomistic Theory of Thermally Activated Magnetization Processes in Nd2Fe14B Permanent Magnet; [Nd2Fe14B 系永久磁石における熱活性磁化過程の原子論的理論]","2022","Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy","69","","","S126","S146","20","2","10.2497/jjspm.69.S126","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85124659700&doi=10.2497%2fjjspm.69.S126&partnerID=40&md5=558f2198d8d0d2dd2e50b15d42fc3492","ISSP, The University of Tokyo, Kashiwa, Japan; NIMS, Tsukuba, Japan; AIST, Japan; Tohoku University, Japan","Miyashita S., ISSP, The University of Tokyo, Kashiwa, Japan; Nishino M., NIMS, Tsukuba, Japan; Toga Y., ISSP, The University of Tokyo, Kashiwa, Japan; Hinokihara T., ISSP, The University of Tokyo, Kashiwa, Japan; Uysal I.E., ISSP, The University of Tokyo, Kashiwa, Japan; Miyake T., AIST, Japan; Akai H., ISSP, The University of Tokyo, Kashiwa, Japan; Hirosawa S., NIMS, Tsukuba, Japan; Sakuma A., Tohoku University, Japan","For the practical use of magnets, particularly at high temperatures, the temperature dependence of magnetic properties is an important ingredient. To study the temperature dependence, methods of treating the thermal fluctuation causing the so-called activation phenomena must be established. To study finite-temperature properties quantitatively, we need atomistic energy information to calculate the canonical distribution. In the present review, we report our recent studies on the thermal properties of the Nd2Fe14B magnet and the methods of studying them. We first propose an atomistic Hamiltonian and show various thermodynamic properties, e.g., the temperature dependences of the magnetization showing a spin reorientation transition, the magnetic anisotropy energy, the domain wall profiles, the anisotropy of the exchange stiffness constant, and the spectrum of ferromagnetic resonance. The effects of the dipole-dipole interaction (DDI) in large grains are also presented. In addition to these equilibrium properties, we also study coercivity, which is the most important issue for magnets. The temperature dependence of the coercivity of a single grain was studied using the stochastic Landau-LifshitzGilbert equation and also by the analysis of the free energy landscape, which was obtained by Monte Carlo simulation. It was found that the upper limit of coercivity at room temperature is about 3 T, which is significantly lower than the so-called theoretical coercivity given by a simple coherent rotation model. The coercivity of a polycrystalline magnet, i.e., an ensemble of grains, is expected to be reduced further by the effects of the grain boundary phase, which is also studied. Surface nucleation is a key ingredient in the domain wall depinning process. Finally, we study the effect of DDI among grains and also discuss the distribution of properties of grains from the viewpoint of first order reversal curve. ©2022 Japan Society of Powder and Powder Metallurgy.","Coercivity; Dipole-dipole interaction; Finite temperature; Monte Carlo method; Stochastic LLG equation; Thermal fluctuation","Boron compounds; Coercive force; Dipole moment; Domain walls; Electric dipole moments; Free energy; Grain boundaries; Intelligent systems; Iron compounds; Magnetic anisotropy; Magnets; Stochastic systems; Temperature distribution; Atomistics; Dipole dipole interactions; Finite temperatures; LLG equation; MonteCarlo methods; Stochastic LLG equation; Stochastics; Temperature dependence; Thermal fluctuations; Thermally activated; Monte Carlo methods","","","","",", (20K03809)","","Sagawa M., Hirosawa S., J. Mater. Res, 3, pp. 45-54, (1988); Herbst J. F., Croat J. J., Pinkerton F. E., Et al., Phys. Rev. B, 29, pp. 4176-4187, (1984); Hirosawa S., Matsuura Y., Yamamoto H., Et al., J. J. Appl. Phys, 24, pp. L803-L805, (1985); Andreev A. V., Deryagin A. V., Kudrevatykh N. V., Et al., Sov. Phys. JETP, 63, pp. 608-612, (1986); Kronmuller H., Phys. Status Solidi B, 144, pp. 385-396, (1987); Herbst J. F., Rev. Mod. Phys, 63, (1991); Hirosawa S., Matsuura Y., Yamamoto H., Et al., J. Appl. Phys, 59, pp. 873-879, (1986); Yamada O., Tokuhara H., Ono F., Et al., J. Magn. Magn. Mater, 54, pp. 585-586, (1986); Mushnikov N. V., Terent'ev P. B., Rosenfel'd E. V., The Physics of Metals and Metallography, 103, pp. 39-50, (2007); Kou X. C., Grossinger R., Hilscher G., Et al., Phys. Rev. B, 54, pp. 6421-6429, (1996); Pique C., Burriel R., Bartolome J., J. Magn. Magn. Mater, 154, pp. 71-82, (1996); Zhang Z. D., Kou X. C., de Boer F. R., Et al., J. Alloys Comp, 274, pp. 274-277, (1998); Chacon C., Isnard O., Miraglia S., J. 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Phys, 104, (2008); Nishino M., Miyashita S.; Yomogita T., Kikuchi N., Okamoto S., Et al., AIP Advance, 9, (2019); Lui J., Seperi-Amin H., Ohkubo T., Et al., Acta Mater, 61, pp. 5387-5399, (2013); Li J., Tang X., Seperi-Amin H., Et al., Acta Mater, 199, pp. 288-296, (2020); Tsuji N., Okazaki H., Ueno W., Et al., Acta Mater, 154, pp. 25-32, (2018); Gohda Y., Science and Technology of Advanced Materials, 22, 1, pp. 113-123, (2021); Hinokihara T., Okuyama Y., Sasaki M., Et al.; AkaiKKR (Machikaneyama); Miyashita S., Nishino M., Toga Y., Et al., Science and Technology of Advanced Materials to be published, (2021)","S. Miyashita; ISSP, The University of Tokyo, Kashiwa, Japan; email: miyashita-seiji@g.ecc.u-tokyo.ac.jp","","Journal of the Japan Society of Powder and Powder Metallurgy","","","","","","05328799","","FOFUA","","Japanese","Funtai Oyobi Fummatsu Yakin","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85124659700" +"Watanabe I.; Hane Y.; Nakamura K.","Watanabe, Itsuki (58173209700); Hane, Yoshiki (36632081800); Nakamura, Kenji (55516112700)","58173209700; 36632081800; 55516112700","Various Examinations on Calculation Accuracy of DC Hysteresis Characteristics by LLG Equation; [LLG 方程式による直流ヒステリシス特性の計算精度に関する諸検討]","2023","IEEJ Transactions on Fundamentals and Materials","143","4","","150","157","7","0","10.1541/ieejfms.143.150","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85151902216&doi=10.1541%2fieejfms.143.150&partnerID=40&md5=6e8eab9489d31880e1830ae1e2505cc1","Graduate School of Engineering, Tohoku University, 6-6-11, Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan","Watanabe I., Graduate School of Engineering, Tohoku University, 6-6-11, Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Hane Y., Graduate School of Engineering, Tohoku University, 6-6-11, Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, 6-6-11, Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan","Quantitative analysis of iron loss taking magnetic hysteresis behavior into account is essential to loss reduction in electric machines. In the previous research, a novel magnetic circuit model, which incorporates a play model and a Cauer circuit, was proposed. Besides, the play model can be derived from dc hysteresis loops calculated by a simplified Landau-Lifshitz-Gilbert (LLG) equation. However, this method cannot necessarily calculate dc hysteresis loops with high accuracy in all cases so that there is potential for further improvement in its calculation accuracy. Therefore, in this paper, the calculation accuracy of the simplified LLG equation is examined in detail under various conditions. © 2023 The Institute of Electrical Engineers of Japan.","Cauer circuit; Landau-Lifshitz-Gilbert (LLG) equation; magnetic circuit model; play model","Circuit simulation; Electric losses; Magnetic circuits; Magnetic hysteresis; Magnetic materials; Timing circuits; Calculation accuracy; Cauer circuits; Hysteresis behavior; Hysteresis characteristics; Iron loss; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Loss reduction; Magnetic circuit model; Play model; Hysteresis loops","","","","","Japan Society for the Promotion of Science, JSPS, (22K14232)","","Bobbio S., Miano G., Serpico C., Visone C., Models of Magnetic Hysteresis Based on Play and Stop Hysteresis, IEEE Trans. Magn, 33, 6, pp. 4417-4426, (1997); Shindo Y., Noro O., Simple Circuit Simulation Models for the Eddy Current in Magnetic Sheets and Wires, IEEJ Trans. FM, 134, 4, pp. 173-181, (2014); Hane Y., Nakamura K., Dynamic Hysteresis Modeling Taking Skin Effect into Account for Magnetic Circuit Analysis and Validation for Various Core Materials, IEEE Trans. Magn, 58, 4, (2022); (2013); Tanaka H., Nakamura K., Ichinokura O., Magnetic Circuit Model combined with Play Model Obtained from Landau-Lifshitz-Gilbert Equation, J. Phys. Conference Series, 903, (2017); (2020); (2021); Tanaka H., Nakamura K., Ichinokura O., Accuracy Improvement of Magnetic Hysteresis Calculated by LLG Equation, J. Phys. Conference Series, 903, (2017); (2017); (2017)","Y. Hane; Graduate School of Engineering, Tohoku University, Sendai, 6-6-11, Aoba, Aramaki, Aoba-ku, 980-8579, Japan; email: yoshiki.hane.e2@tohoku.ac.jp","","Institute of Electrical Engineers of Japan","","","","","","03854205","","","","Japanese","IEEJ Trans. Fundam. Mater.","Article","Final","","Scopus","2-s2.0-85151902216" +"Hane Y.","Hane, Y. (36632081800)","36632081800","Hysteresis Modeling for Power Magnetic Devices Based on Magnetic Circuit Method","2022","Journal of the Magnetics Society of Japan","46","2","","22","36","14","3","10.3379/msjmag.2203RV001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125870343&doi=10.3379%2fmsjmag.2203RV001&partnerID=40&md5=43c4dba798ed21eaf5f12ffc182168f8","Graduate School of Engineering, Tohoku Univ, 6-6-11 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan","Hane Y., Graduate School of Engineering, Tohoku Univ, 6-6-11 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan","This paper introduces the latest research achievements on the hysteresis modeling for power magnetic devices based on the magnetic circuit method. First, the magnetic circuit model considering the magnetic hysteresis behavior is derived. Next, this magnetic circuit model is developed to the reluctance network model, to analyze more complicated devices such as an electric motor. Furthermore, this magnetic circuit model is improved to take the dynamic hysteresis characteristics including the skin effect into account. Finally, the prediction method of the deteriorated hysteresis loops in core material due to machining process is established. © 2022, Magnetics Society of Japan. All rights reserved.","Cauer circuit; Landau-Lifshitz-Gilbert (LLG) equation; Magnetic circuit method; Play model; Reluctance network analysis (RNA)","Circuit simulation; Coremaking; Machining; Magnetic circuits; Magnetism; Cauer circuits; Hysteresis behavior; Hysteresis models; Landau-Lifshitz-Gilbert equations; Magnetic circuit method; Magnetic circuit model; Play model; Reluctance network analyse; Reluctance network analysis; Research achievements; Timing circuits","","","","","JSPS, (19J20572)","This work was supported by Grant-in-Aid for JSPS Fellows (JP19J20572).","Steinmetz C. P., Proc. IEEE, 72, (1984); Bertotti G., IEEE Trans. Magn, 24, (1988); Venkatachalam K., Sullivan C. R., Abdallah T., Tacca H., Conf. Proc. IEEE, 36, (2002); Yanase S., Kimata H., Okazaki Y., Hayashi S., IEEE Trans. Magn, 41, (2005); Shen W., Wang F., Borovevich D., Tipton C. W., IEEE Trans. Power Electron, 23, (2008); Jiles D. C., Atherton D. L., J. Magn. Magn. Mater, 61, (1986); Friedman G., J. Appl. Phys, 67, (1990); Park G. S., Hahn S. Y., Lee K. S., Jung H. K., IEEE Trans. Magn, 29, (1993); Bobbio S., Miano G., Serpico C., Visone C., IEEE Trans. Magn, 33, (1997); Tanaka H., Nakamura K., Ichinokura O., J. Phys: Conf. Series, 903, (2017); Oshima H., Uehara Y., Shimizu K., Inagaki K., Furuya A., Fujisaki J., Suzuki M., Kawano K., Mifune T., Matsuo T., Watanabe K., Igarashi H., J. Jpn. Soc. Powder Metallurgy, 61, (2013); Tanaka H., Nakamura K., Ichinokura O., J. Magn. Soc. Jpn, 39, (2015); Tanaka H., Nakamura K., Ichinokura O., J. Phys: Conf. Series, 903, (2017); Karapetoff V., The Magnetic Circuit, (1911); Fujita K., Nakamura K., Ichinokura O., J. Magn. Soc. 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IEEE, (2021); Yamazaki K., Fukushima N., IEEE Trans. EC, 25, (2010); Takeda Y., Takahashi Y., Fujiwara K., Ahagon A., Matsuo T., IEEE Trans. Magn, 51, (2015); Shindo Y., Noro O., IEEJ. Trans. FM, 134, (2014); Shindo Y., Kameari A., Matsuo T., PE, 137, (2017); Suehiro I., Mifune T., Matsuo T., Kitao J., Komatsu T., Nakano M., IEEE Trans. Magn, 54, (2018); Minowa N., Takahashi Y., Fujiwara K., IEEE Trans. Magn, 55, (2019); Hane Y., Nakamura K., IEEE Trans. Magn, 56, (2020); Fujisaki K., Hirayama R., Kawachi T., Satou S., Kaidou C., Yabumoto M., Kubota T., IEEE Trans. Magn, 43, (2007); Miyagi D., Miki K., Nakano M., Takahashi N., IEEE Trans. Magn, 46, (2010); Yamazaki K., Fukuoka W., IEEE Trans. Magn, 51, (2015); Yamazaki K., Aoki A., IEEE Trans. Magn, 52, (2016); Furuya A., Fujisaki J., Uehara Y., Shimizu K., Oshima H., Matsuo T., IEEE Trans. Magn, 50, (2014); Hane Y., Nakamura K., Yoshioka T., Kawase T., Ishikawa T., Trans. Magn. Special Issues, 3, (2019); Hane Y., Nakamura K., Kawase T., Hosokawa N., Kurimoto N., Trans. Magn. Special Issues, 4, (2020)","Y. Hane; Graduate School of Engineering, Tohoku Univ, Sendai, 6-6-11 Aoba Aramaki, Aoba-ku, 980-8579, Japan; email: yoshiki.hane.e2@tohoku.ac.jp","","Magnetics Society of Japan","","","","","","02850192","","","","English","J. Magnetics Soc. Japan","Review","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85125870343" +"Ovcharenko S.; Gaponov M.; Klimov A.; Tiercelin N.; Pernod P.; Mishina E.; Sigov A.; Preobrazhensky V.","Ovcharenko, Sergei (7005355364); Gaponov, Mikhail (57216266247); Klimov, Alexey (35391085300); Tiercelin, Nicolas (6603515103); Pernod, Philippe (7003429648); Mishina, Elena (7005350309); Sigov, Alexander (35557510600); Preobrazhensky, Vladimir (7004493603)","7005355364; 57216266247; 35391085300; 6603515103; 7003429648; 7005350309; 35557510600; 7004493603","Ultrafast manipulation of magnetic anisotropy in a uniaxial intermetallic heterostructure TbCo2/FeCo","2022","Journal of Physics D: Applied Physics","55","17","175001","","","","1","10.1088/1361-6463/ac4a9a","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125439876&doi=10.1088%2f1361-6463%2fac4a9a&partnerID=40&md5=7e3f643883d441a116baa96bbec2c5ea","MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520-IEMN, Lille, 59000, France; Prokhorov General Physics Institute of RAS, Moscow, 119991, Russian Federation","Ovcharenko S., MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Gaponov M., MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Klimov A., MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Tiercelin N., Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520-IEMN, Lille, 59000, France; Pernod P., Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520-IEMN, Lille, 59000, France; Mishina E., MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Sigov A., MIREA-Russian Technological University, Moscow, 119454, Russian Federation; Preobrazhensky V., Prokhorov General Physics Institute of RAS, Moscow, 119991, Russian Federation","We study experimentally and theoretically the dynamics of spin relaxation motion excited by a femtosecond pulse in the TbCo2/FeCo multilayer structures with different ratios of TbCo2 to FeCo thicknesses rd=dTbCo2/dFeCo. The main attribute of the structure is in-plane magnetic anisotropy that is artificially induced during sputtering under a DC magnetic field. The optical pump-probe method revealed strongly damped high-frequency oscillations of the dynamical Kerr rotation angle, followed by its slow relaxation to the initial state. Modeling experimental results using the Landau-Lifshitz-Gilbert (LLG) equation showed that the observed entire dynamics is due to destruction and restoration of magnetic anisotropy rather than to demagnetization. For the pumping fluence of 7 mJ cm-2, the maximal photo-induced disruption of the anisotropy field is about 14% for the sample with rd=1 and decreases when rd increases. The anisotropy relaxation is a three-stage process: the ultrafast one occurs within several picoseconds, and the slow one occurs on a nanosecond time scale. The Gilbert damping in the multilayers is found to be one order of magnitude higher than that in the constituent monolayers. © 2022 IOP Publishing Ltd.","Landau-Lifschitz-Gilbert equation; magnetic anisotropy; pump-probe; spintronics; ultrafast magnetization dynamics","Cobalt alloys; Dynamics; Electromagnetic pulse; Intermetallics; Iron alloys; Magnetic anisotropy; Magnetism; Optical pumping; Probes; Spin dynamics; DC magnetic field; Femtoseconds; In-plane magnetic anisotropy; Landau-lifschitz-gilbert equation; Multilayer structures; Pump probe; Pump-probe methods; Spin relaxation; Ultrafast magnetization dynamics; Ultrafast manipulation; Binary alloys","","","","","French RENATECH network; Russian Science Foundation, RSF, (20-12-00276)","This work was supported by Russian Science Foundation (Grant No. 20-12-00276). Fabrication of the samples was supported by French RENATECH network. 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Ovcharenko; MIREA-Russian Technological University, Moscow, 119454, Russian Federation; email: serg30101993@gmail.com","","IOP Publishing Ltd","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85125439876" +"Akrivis G.; Feischl M.; Kovacs B.; Lubich C.","Akrivis, Georgios (56535240600); Feischl, Michael (52363525000); Kovacs, Balázs (57203544797); Lubich, Christian (7003864444)","56535240600; 52363525000; 57203544797; 7003864444","HIGHER-ORDER LINEARLY IMPLICIT FULL DISCRETIZATION OF THE LANDAU-LIFSHITZ-GILBERT EQUATION","2021","Mathematics of Computation","90","329","","995","1038","43","23","10.1090/mcom/3597","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85100252596&doi=10.1090%2fmcom%2f3597&partnerID=40&md5=d59e07643ed668f016ded7cd70d7d1f8","Department of Computer Science & Engineering, University of Ioannina, Ioannina, 451 10, Greece; Institute of Applied and Computational Mathematics, FORTH, Heraklion, Crete, 700 13, Greece; Institute for Analysis and Scientific Computing (E 101), Technical University Wien, Wiedner Hauptstrasse 8-10, Vienna, 1040, Austria; Mathematisches Institut, Universität Tubingen, Auf der Morgenstelle, Tubingen, D-72076, Germany; Mathematisches Institut, Universität Tübingen, Auf der Morgenstelle, Tubingen, D-72076, Germany","Akrivis G., Department of Computer Science & Engineering, University of Ioannina, Ioannina, 451 10, Greece, Institute of Applied and Computational Mathematics, FORTH, Heraklion, Crete, 700 13, Greece; Feischl M., Institute for Analysis and Scientific Computing (E 101), Technical University Wien, Wiedner Hauptstrasse 8-10, Vienna, 1040, Austria; Kovacs B., Mathematisches Institut, Universität Tubingen, Auf der Morgenstelle, Tubingen, D-72076, Germany; Lubich C., Mathematisches Institut, Universität Tübingen, Auf der Morgenstelle, Tubingen, D-72076, Germany","For the Landau-Lifshitz-Gilbert (LLG) equation of micromagnetics we study linearly implicit backward difference formula (BDF) time discretizations up to order 5 combined with higher-order non-conforming finite element space discretizations, which are based on the weak formulation due to Alouges but use approximate tangent spaces that are defined by L2-averaged instead of nodal orthogonality constraints. We prove stability and optimalorder error bounds in the situation of a sufficiently regular solution. For the BDF methods of orders 3 to 5, this requires that the damping parameter in the LLG equations be above a positive threshold; this condition is not needed for the A-stable methods of orders 1 and 2, for which furthermore a discrete energy inequality irrespective of solution regularity is proved. © 2021 American Mathematical Society. All Rights Reserved.","BDF methods; energy technique; Landau— Lifshitz-Gilbert equation; non-conforming finite element method; stability","","","","","","Deutsche Forschungsgemeinschaft, DFG, (258734477 – SFB 1173); Deutsche Forschungsgemeinschaft, DFG","Received by the editor March 13, 2019, and, in revised form, March 14, 2020. 2020 Mathematics Subject Classification. Primary 65M12, 65M15; Secondary 65L06. Key words and phrases. BDF methods, non-conforming finite element method, Landau– Lifshitz–Gilbert equation, energy technique, stability. The work of the second, third, and fourth authors were supported by Deutsche Forschungsge-meinschaft – Project-ID 258734477 – SFB 1173.","Akrivis G., Katsoprinakis E., Backward difference formulae: new multipliers and stability properties for parabolic equations, Math. Comp, 85, 301, pp. 2195-2216, (2016); Akrivis G., Li B., Lubich C., Combining maximal regularity and energy estimates for time discretizations of quasilinear parabolic equations, Math.Comp, 86, 306, pp. 1527-1552, (2017); Akrivis G., Lubich C., Fully implicit, linearly implicit and implicit-explicit backward difference formulae for quasi-linear parabolic equations, Numer. Math, 131, 4, pp. 713-735, (2015); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, 2, pp. 187-196, (2008); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl. 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Comput.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85100252596" +"Tang Y.-H.; Huang B.-H.","Tang, Yu-Hui (56161704900); Huang, Bao-Huei (57216387663)","56161704900; 57216387663","Underlying mechanism for exchange bias in single-molecule magnetic junctions","2021","Physical Review Research","3","3","033264","","","","4","10.1103/PhysRevResearch.3.033264","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85116375898&doi=10.1103%2fPhysRevResearch.3.033264&partnerID=40&md5=e25ac6946cac5eeead3b403c2774ce08","Department of Physics, National Central University, Jung-Li, 32001, Taiwan","Tang Y.-H., Department of Physics, National Central University, Jung-Li, 32001, Taiwan; Huang B.-H., Department of Physics, National Central University, Jung-Li, 32001, Taiwan","Magnetic proximity has been observed in a variety of solid-state magnetic devices, but has been less discussed at the molecular scale. In this study, the magnetotransport calculation is carried out using the generalized Landau-Lifshitz-Gilbert (LLG) equation combined with density functional theory (DFT) and our self-developed junpy calculated spin-torque effect. Except for the current driven spin torque, which is a promising approach for magnetization switch in magnetic random access memory, the equilibrium fieldlike spin torque also plays a crucial role in the strain-controlled exchange bias with current-controlled magnetic coercivity in single-molecule magnetic junctions. The tight-binding model is further employed to clarify the critical role of the interfacial spin filter effect arising from the hybridization between the linker and Co apex. These multidisciplinary DFT+junpy+LLG results may provide important and practical implications in the dual control of magnetic proximity and magnetization switching in molecular spintronics at low temperature, either by tensile strain or via smaller applied current density of the order of . © 2021 Published by the American Physical Society","","Magnetic storage; Magnetization; Molecules; Random access storage; Temperature; Tensile strain; Current-driven; Density-functional-theory; Exchange bias; Landau-Lifshitz-Gilbert equations; Magnetic proximity; Magnetic random access memory; Molecular scale; Single molecule; Spin torque; Spin-torque effect; Density functional theory","","","","","Ministry of Science and Technology, Taiwan National Center for Theoretical Sciences; National Center for Theoretical Sciences, NCTS; Ministry of Science and Technology, Taiwan, MOST, (107-2633-M-008-004-, 108-2628-M-008-004-MY3)","Funding text 1: Ministry of Science and Technology, Taiwan National Center for Theoretical Sciences; Funding text 2: We thank the National Center for High-performance Computing (NCHC) of the National Applied Research Laboratories (NARLabs) in Taiwan for providing computational and storage resources. 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D., Dieny B., Respective influence of in-plane and out-of-plane spin-transfer torques in magnetization switching of perpendicular magnetic tunnel junctions, Phys. Rev. B, 92, (2015); Petta J. R., Slater S. K., Ralph D. C., Spin-Dependent Transport in Molecular Tunnel Junctions, Phys. Rev. Lett, 93, (2004); Bogani L., Wernsdorfer W., Molecular spintronics using single-molecule magnets, Nat. Mater, 7, (2008); Chiang K.-R., Tang Y.-H., Effect of contact geometry on spin transport in amine-ended single-molecule magnetic junctions, ACS Omega, 6, (2021)","","","American Physical Society","","","","","","26431564","","","","English","Phys. Rev. Res.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85116375898" +"Di Fratta G.; Pfeiler C.-M.; Praetorius D.; Ruggeri M.; Stiftner B.","Di Fratta, Giovanni (23093879900); Pfeiler, Carl-Martin (57208439571); Praetorius, Dirk (6507452481); Ruggeri, Michele (56196953600); Stiftner, Bernhard (57200730751)","23093879900; 57208439571; 6507452481; 56196953600; 57200730751","Linear second-order IMEX-type integrator for the (eddy current) Landau–Lifshitz–Gilbert equation","2020","IMA Journal of Numerical Analysis","40","4","","2802","2838","36","16","10.1093/imanum/drz046","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85097262224&doi=10.1093%2fimanum%2fdrz046&partnerID=40&md5=fb098650ca5ba9df0842428f938ee178","Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria","Di Fratta G., Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Pfeiler C.-M., Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Praetorius D., Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Ruggeri M., Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria; Stiftner B., Institute for Analysis and Scientific Computing, TU Wien, Wiedner Hauptstrasse 8–10, Vienna, 1040, Austria","Combining ideas from Alouges et al. (2014, A convergent and precise finite element scheme for Landau–Lifschitz–Gilbert equation. Numer. Math., 128, 407–430) and Praetorius et al. (2018, Convergence of an implicit-explicit midpoint scheme for computational micromagnetics. Comput. Math. Appl., 75, 1719–1738) we propose a numerical algorithm for the integration of the nonlinear and time-dependent Landau–Lifshitz–Gilbert (LLG) equation, which is unconditionally convergent, formally (almost) second-order in time, and requires the solution of only one linear system per time step. Only the exchange contribution is integrated implicitly in time, while the lower-order contributions like the computationally expensive stray field are treated explicitly in time. Then we extend the scheme to the coupled system of the LLG equation with the eddy current approximation of Maxwell equations. Unlike existing schemes for this system, the new integrator is unconditionally convergent, (almost) second-order in time, and requires the solution of only two linear systems per time step. © The Author(s) 2019. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.","Finite elements; Implicit-explicit time-marching scheme; Linear second-order time integration; Micromagnetism; Unconditional convergence","Eddy currents; Linear systems; Nonlinear equations; Coupled systems; Eddy current approximation; Finite element schemes; Implicit-explicit; Micromagnetics; Midpoint scheme; Numerical algorithms; Time dependent; Maxwell equations","","","","","Vienna Science and Technology Fund, WWTF; Vienna Science and Technology Fund, WWTF, (MA14-44)","PDEs (grant W1245); special research program Taming Complexity in Partial Differential Systems (grant SFB F65); Vienna Science and Technology Fund (WWTF) through the project Thermally Controlled Magnetization Dynamics (grant MA14-44).","Abert C., Exl L., Selke G., Drews A., Schrefl T., Numerical methods for the stray-field calculation: a comparison of recently developed algorithms, J. Magn. Magn. Mater, 326, pp. 176-185, (2013); Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suess D., Spin-polarized transport in ferromagnetic multilayers: an unconditionally convergent FEM integrator, Comput. Math. Appl, 68, pp. 639-654, (2014); Alouges F., A new finite element scheme for Landau–Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Di Fratta G., Merlet B., Liouville type results for local minimizers of the micromagnetic energy, Calc. Var. Partial Differential Equations, 53, pp. 525-560, (2015); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau–Lifshitz equation in micromagnetism, Math. Models Methods Appl. Sci, 16, pp. 299-316, (2006); Alouges F., Kritsikis E., Steiner J., Toussaint J.-C., A convergent and precise finite element scheme for Landau–Lifschitz–Gilbert equation, Numer. Math, 128, pp. 407-430, (2014); Alouges F., Kritsikis E., Toussaint J.-C., A convergent finite element approximation for Landau–Lifschitz–Gilbert equation, Physica B, 407, pp. 1345-1349, (2012); Alouges F., Soyeur A., On global weak solutions for Landau–Lifshitz equations: existence and nonuniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Baibich M. N., Broto J. M., Fert A., Van Dau F. N., Petroff F., Etienne P., Creuzet G., Friederich A., Chazelas J., Giant magnetoresistance of (001)Fe/(001) Cr magnetic superlattices, Phys. Rev. Lett, 61, pp. 2472-2475, (1988); Banas L., Page M., Praetorius D., A convergent linear finite element scheme for the Maxwell–Landau–Lifshitz–Gilbert equations, Electron. Trans. Numer. Anal, 44, pp. 250-270, (2015); Banas L., Page M., Praetorius D., Rochat J., A decoupled and unconditionally convergent linear FEM integrator for the Landau–Lifshitz–Gilbert equation with magnetostriction, IMA J. Numer. Anal, 34, pp. 1361-1385, (2014); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal, 43, pp. 220-238, (2005); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau–Lifshitz–Gilbert equation, SIAM J. Numer. Anal, 44, pp. 1405-1419, (2006); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Bertotti G., Magni A., Mayergoyz I. D., Serpico C., Landau–Lifshitz magnetization dynamics and eddy currents in metallic thin films, J. Appl. Phys, 91, (2002); Binasch G., Grunberg P., Saurenbach F., Zinn W., Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange, Phys. Rev. B, 39, pp. 4828-4830, (1989); Bruckner F., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Ruggeri M., Suess D., Multiscale modeling in micromagnetics: existence of solutions and numerical integration, Math. Models Methods Appl. Sci, 24, pp. 2627-2662, (2014); Cimrak I., A survey on the numerics and computations for the Landau–Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng, 15, pp. 277-309, (2008); Di Fratta G., Pfeiler C.-M., Praetorius D., Ruggeri M., Stiftner B., Linear second order IMEX-type integrator for the (eddy current) Landau–Lifshitz–Gilbert equation, (2017); Donahue M. J., Porter D. G., OOMMF User’s Guide, Version 1.0, Interagency Report NISTIR 6376, (1999); Feischl M., Tran T., The eddy current–LLG equations: FEM-BEM coupling and a priori error estimates, SIAM J. Numer. Anal, 55, pp. 1786-1819, (2017); Fredkin D. R., Koehler T. R., Hybrid method for computing demagnetization fields, IEEE Trans. Magn, 26, pp. 415-417, (1990); Garcia-Cervera C. J., Numerical micromagnetics: a review, Bol. Soc. Esp. Mat. Apl. SeMA, 39, pp. 103-135, (2007); Gilbert T. L., A Lagrangian formulation of the gyromagnetic equation of the magnetization fields, Phys. Rev, 100, (1955); Hosomi M., Yamagishi H., Yamamoto T., Bessho K., Higo Y., Yamane K., Yamada H., Shoji M., Hachino H., Fukumoto C., Nagao H., Kano H., A novel nonvolatile memory with spin torque transfer magnetization switching: Spin-RAM, Proceedings of the IEEE International Electron Devices Meeting 2005. IEDM Technical Digest, pp. 459-462, (2005); Hrkac G., Schrefl T., Ertl O., Suess D., Kirschner M., Dorfbauer F., Fidler J., Influence of eddy current on magnetization processes in submicrometer permalloy structures, IEEE Trans. Magn, 41, pp. 3097-3099, (2005); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. der Sow, 8, pp. 153-168, (1935); Le K.-N., Page M., Praetorius D., Tran T., On a decoupled linear FEM integrator for eddy-current-LLG, Appl. Anal, 94, pp. 1051-1067, (2015); Le K.-N., Tran T., A convergent finite element approximation for the quasi-static Maxwell–Landau–Lifshitz–Gilbert equations, Comput. Math. Appl, 66, pp. 1389-1402, (2013); Nedelec J. C., A new family of mixed finite elements in QT, Numer. Math, 50, pp. 57-81, (1986); (2014); Pfeiler C.-M., Ruggeri M., Stiftner B., Exl L., Hochsteger M., Hrkac G., Schoberl J., Mauser N. J., Praetorius D., Computational micromagnetics with Commics, Comput. Phys. Commun, (2019); Praetorius D., Analysis of the operator Δ−1 div arising in magnetic models, Z. Anal. Anwend, 23, pp. 589-605, (2004); Praetorius D., Ruggeri M., Stiftner B., Convergence of an implicit–explicit midpoint scheme for computational micromagnetics, Comput. Math. Appl, 75, pp. 1719-1738, (2018); Prohl A., Computational micromagnetism, Advances in Numerical Mathematics, (2001); Quarteroni A., Valli A., Numerical Approximation of Partial Differential Equations, Springer Series in Computational Mathematics, 23, (1994); Schoberl J., Netgen/NGSolve, (2017); Slonczewski J. C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mat, 159, pp. L1-L7, (1996); Smigaj W., Betcke T., Arridge S., Phillips J., Schweiger M., Solving boundary integral problems with BEM++, ACM Trans. Math. Softw, 41, 1–6, (2015); Sun J., Collino F., Monk P. B., Wang L., An eddy-current and micromagnetism model with applications to disk write heads, Internat. J. Numer. Methods Engrg, 60, pp. 1673-1698, (2004); Thiaville A., Nakatani Y., Miltat J., Suzuki Y., Micromagnetic understanding of current-driven domain wall motion in patterned nanowires, Europhys. Lett, 69, pp. 990-996, (2005); Zhang S., Li Z., Roles of nonequilibrium conduction electrons on the magnetization dynamics of ferromagnets, Phys. Rev. Lett, 93, (2004)","B. Stiftner; Institute for Analysis and Scientific Computing, TU Wien, Vienna, Wiedner Hauptstrasse 8–10, 1040, Austria; email: bernhard.stiftner@asc.tuwien.ac.at","","Oxford University Press","","","","","","02724979","","","","English","IMA J. Numer. Anal.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85097262224" +"Ferrero R.; Manzin A.","Ferrero, Riccardo (57204107066); Manzin, Alessandra (12789918800)","57204107066; 12789918800","Adaptive geometric integration applied to a 3D micromagnetic solver","2021","Journal of Magnetism and Magnetic Materials","518","","167409","","","","6","10.1016/j.jmmm.2020.167409","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85092113557&doi=10.1016%2fj.jmmm.2020.167409&partnerID=40&md5=8bf8aaceaae015230ff0e331b576c3aa","Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, Torino, 10135, Italy","Ferrero R., Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, Torino, 10135, Italy; Manzin A., Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, Torino, 10135, Italy","This paper presents a GPU-parallelized 3D micromagnetic code for the efficient calculation of the magnetization dynamics, equilibrium configuration and static hysteresis loops of magnetic nanostructures, by solving the Landau-Lifshitz-Gilbert (LLG) equation. The time-integration of the LLG equation is carried out by using a technique based on the Cayley transform, which allows us to fulfil the constraint on the magnetization amplitude. The computational domain is reconstructed with a structured hexahedral mesh. The spatial-integration of the magnetostatic field is performed via a Fast Fourier Transform (FFT) algorithm, and the exchange field is computed with a 26-node-based finite difference technique. A careful validation of the developed solver was carried out, also by comparison to OOMMF and MuMax3. Then, we analysed the computational efficiency of the geometrical time-integrator and of its time-adaptive variant, investigating the role of the numerical damping introduced by the Cayley transform-based time-discretization. © 2020 Elsevier B.V.","GPU computing; Landau-Lifshitz-Gilbert equation; Micromagnetics; Numerical modelling","Computational efficiency; Fast Fourier transforms; Graph Databases; Magnetic materials; Magnetization; Magnetostatics; Equilibrium configuration; Fast Fourier transform algorithm; Finite-difference techniques; Geometric integration; Landau-Lifshitz-Gilbert equations; Magnetic nanostructures; Magnetization dynamics; Static hysteresis loops; Integration","","","","","Horizon 2020 Framework Programme, H2020; European Metrology Programme for Innovation and Research, EMPIR; Horizon 2020","Funding text 1: The work here presented was developed in the framework of the 18HLT06 RaCHy Project that received funding from the EMPIR Program, co-financed by the Participating States, and from the European Union’s Horizon 2020 Research and Innovation Program.; Funding text 2: The work here presented was developed in the framework of the 18HLT06 RaCHy Project that received funding from the EMPIR Program, co-financed by the Participating States, and from the European Union's Horizon 2020 Research and Innovation Program.","d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, J. Comput. Phys., 209, pp. 730-753, (2005); Van de Wiele B., Olyslager F., Dupre L., Fast semianalytical time integration schemes for the Landau-Lifshitz equation, IEEE Trans. Magn., 43, pp. 2917-2919, (2007); Porter D.G., Donahue M.J., Precession axis modification to a semianalytical Landau-Lifshitz solution technique, J. Appl. Phys., 103, (2008); Vansteenkiste A., Van De Wiele B., MUMAX: a new high-performance micromagnetic simulation tool, J. Magn. Magn. Mater., 323, pp. 2585-2591, (2011); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo G., Azzerboni B., A numerical solution of the magnetization reversal modeling in a permalloy thin film using fifth order Runge-Kutta method with adaptive step size control, Phys. B Condens. Matter., 403, pp. 464-468, (2008); Wang X., Garcia-Cervera C.J., (2001); Serpico C., Mayergoyz I.D., Bertotti G., (2001); Exl L., Mauser N.J., Schrefl T., Suess D., The extrapolated explicit midpoint scheme for variable order and step size controlled integration of the Landau–Lifschitz–Gilbert equation, J. Comput. Phys., 346, pp. 14-24, (2017); Suess D., Tsiantos V., Schrefl T., Fidler J., Scholz W., Forster H., Dittrich R., Miles J.J., Time resolved micromagnetics using a preconditioned time integration method, J. Magn. Magn. Mater., 248, pp. 298-311, (2002); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: fast micromagnetic simulator for complex magnetic structures, J. Appl. Phys., 109, (2011); Bottauscio O., Chiampi M., Manzin A., A finite element procedure for dynamic micromagnetic computations, IEEE Trans. Magn., 44, 11, pp. 3149-3152, (2008); Bartels S., Constraint preserving, inexact solution of implicit discretizations of Landau–Lifshitz–Gilbert equations and consequences for convergence, PAMM Proc. Appl. Math. Mech., 6, pp. 19-22, (2006); Crouch P.E., Grossman R., Numerical integration of ordinary differential equations on manifolds, J. Nonlinear Sci., 3, pp. 1-33, (1993); Lewis D., Simo J.C., Conserving algorithms for the dynamics of Hamiltonian systems on Lie groups, J. Nonlinear Sci., 4, pp. 253-299, (1994); Munthe-Kaas H., Runge-Kutta methods on Lie groups, BIT Numer. Math., 38, pp. 92-111, (1998); Celledoni E., Marthinsen H., Owren B., An introduction to Lie group integrators – basics, new developments and applications, J. Comput. Phys., 257, pp. 1040-1061, (2014); Krishnaprasad P.S., Tan X., Cayley transforms in micromagnetics, Physica B: Condensed Matter, 306, pp. 195-199, (2001); Lewis D., Nigam N., Geometric integration on spheres and some interesting applications, J. Comput. Appl. Math., 151, pp. 141-170, (2003); Bottauscio O., Manzin A., Efficiency of the geometric integration of Landau–Lifshitz–Gilbert equation based on Cayley transform, IEEE Trans. Magn., 47, pp. 1154-1157, (2011); Manzin A., Ferrero R., A 2.5D micromagnetic solver for randomly distributed magnetic thin objects, J. Magn. Magn. Mater., 492, (2019); Vansteenkiste A., Leliaert J., Dvornik M., Helsen M., Garcia-Sanchez F., Van Waeyenberge B., The design and verification of MuMax3, AIP Adv., 4, (2014); Cash J.R., Karp A.H., A variable order Runge-Kutta method for initial value problems with rapidly varying right-hand sides, ACM Trans. Math. Softw., 16, pp. 201-222, (1990); Dormand J.R., Prince P.J., A reconsideration of some embedded Runge-Kutta formulae, J. Comput. Appl. Math., 15, pp. 203-211, (1986); Ryne R.D., (2011); Exl L., Schrefl T., Non-uniform FFT for the finite element computation of the micromagnetic scalar potential, J. Comput. Phys., 270, pp. 490-505, (2014); Van de Wiele B., Olyslager F., Dupre L., De Zutter D., On the accuracy of FFT based magnetostatic field evaluation schemes in micromagnetic hysteresis modeling, J. Magn. Magn. Mater., 322, pp. 469-476, (2010); Garcia-Cervera C.J., Gimbutas Z., Weinan E., Accurate numerical methods for micromagnetics simulations with general geometries, J. Comput. Phys., 184, pp. 37-52, (2003); Kakay A., Westphal E., Hertel R., Speedup of FEM micromagnetic simulations with graphical processing units, IEEE Trans. Magn., 46, pp. 2303-2306, (2010); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., (2011); Lopez-Diaz L., Aurelio D., Torres L., Martinez E., Hernandez-Lopez M.A., Gomez J., Alejos O., Carpentieri M., Finocchio G., Consolo G., Micromagnetic simulations using graphics processing units, J. Phys. D: Appl. Phys., 45, (2012); Bottauscio O., Manzin A., Parallelized micromagnetic solver for the efficient simulation of large patterned magnetic nanostructures, J. Appl. Phys., 115, (2014); Ferrero R., Manzin A., Barrera G., Celegato F., Coisson M., Tiberto P., Influence of shape, size and magnetostatic interactions on the hyperthermia properties of permalloy nanostructures, Sci. Rep., 9, (2019); Leliaert J., Dvornik M., Mulkers J., De Clercq J., Milosevic M.V., Van Waeyenberge B., Fast micromagnetic simulations on GPU – recent advances made with mumax3, J. Phys. D Appl. Phys., 51, (2018); Celledoni E., Iserles A., Approximating the exponential from a lie algebra to a lie group, Math. Comp., 69, pp. 1457-1480, (2000); Press W., Teukolsky S., Vetterling W., Flannery B., Ziegel E., Flannery B., Teukolsky S., Vetterling W., Numerical recipes: the art of scientific computing, Cambridge University Press, (1987); Zhu R., Grace: a cross-platform micromagnetic simulator on graphics processing units, SoftwareX, 3-4, pp. 27-31, (2015); Cooley B.J.W., Tukey J.W., (1965); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the Landau-Lifshiftz-Gilbert equation for micromagnetics, Jpn. J. Appl. Phys., 28, pp. 2485-2507, (1989); Reilly R.C.O., Beck J.M., A family of large-stencil discrete laplacian approximations in three dimensions, Int. J. Numer. Methods Eng., pp. 1-16, (2006); Donahue M.J., Porter D.G., Exchange energy formulations for 3D micromagnetics, Physica B: Condensed Matter, 343, pp. 177-183, (2004); Miltat J.E., Donahue M.J., Numerical micromagnetics: finite difference methods, Handb. Magn. Adv. Magn. Mater., pp. 1-23, (2007); Van de Wiele B., Manzin A., Dupre L., Olyslager F., Bottauscio O., Chiampi M., Comparison of finite-difference and finite-element schemes for magnetization processes in 3-D particles, IEEE Trans. Magn., 45, pp. 1614-1617, (2009); Manzin A., Bottauscio O., Connections between numerical behavior and physical parameters in the micromagnetic computation of static hysteresis loops, J. Appl. Phys., 108, (2010)","R. Ferrero; Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Strada delle Cacce 91, 10135, Italy; email: r.ferrero@inrim.it","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85092113557" +"Scalera V.; Hudl M.; Neeraj K.; Perna S.; D'Aquino M.; Bonetti S.; Serpico C.","Scalera, V. (57193953627); Hudl, M. (25958109800); Neeraj, K. (57194112313); Perna, S. (56439259300); D'Aquino, M. (9732823500); Bonetti, S. (23972463400); Serpico, C. (23013514800)","57193953627; 25958109800; 57194112313; 56439259300; 9732823500; 23972463400; 23013514800","Analysis in k-Space of Magnetization Dynamics Driven by Strong Terahertz Fields","2021","IEEE Transactions on Magnetics","57","2","9159608","","","","2","10.1109/TMAG.2020.3014383","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85099575744&doi=10.1109%2fTMAG.2020.3014383&partnerID=40&md5=16e6b27273b0a2e62493b1d5c3527d19","Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy; Department of Physics, Stockholm University, Stockholm, Sweden; Department of Engineering, University of Naples 'Parthenope', Naples, Italy","Scalera V., Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy; Hudl M., Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy; Neeraj K., Department of Physics, Stockholm University, Stockholm, Sweden; Perna S., Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy; D'Aquino M., Department of Engineering, University of Naples 'Parthenope', Naples, Italy; Bonetti S., Department of Physics, Stockholm University, Stockholm, Sweden; Serpico C., Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy","Demagnetization in a thin film due to a terahertz pulse of magnetic field is investigated. Linearized Landau-Lifshitz-Gilbert (LLG) equation in the Fourier space to describe the magnetization dynamics is derived, and spin wave time evolution is studied. Finally, the demagnetization due to spin wave dynamics and recent experimental observations on similar magnetic system is compared. As a result, the marginal role of spin wave dynamics in loss of magnetization is established. © 1965-2012 IEEE.","Demagnetization; spin waves analysis; ultrafast magnetization dynamics","Demagnetization; Dynamics; Magnetization; Spin waves; Fourier space; K space; LLG equation; Magnetic system; Magnetization dynamics; Terahertz fields; Terahertz pulse; Time evolutions; Spin fluctuations","","","","","Horizon 2020 Framework Programme, H2020, (715452)","","Walowski J., Munzenberg M., Perspective: Ultrafast magnetism and THz spintronics, J. Appl. Phys., 120, 14, (2016); Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Ultrafast spin dynamics in ferromagnetic nickel, Phys. Rev. Lett., 76, 22, pp. 4250-4253, (1996); Kirilyuk A., Kimel A.V., Rasing T., Ultrafast optical manipulation of magnetic order, Rev. Mod. Phys., 82, 3, pp. 2731-2784, (2010); Hudl M., Et al., Nonlinear magnetization dynamics driven by strong terahertz fields, Phys. Rev. Lett., 123, 19, pp. 197-204, (2019); Bonetti S., Et al., THz-driven ultrafast spin-lattice scattering in amorphous metallic ferromagnets, Phys. Rev. Lett., 117, 8, (2016); Gamble S.J., Et al., Electric field induced magnetic anisotropy in a ferromagnet, Phys. Rev. Lett., 102, 21, (2009); Suhl H., The theory of ferromagnetic resonance at high signal powers, J. Phys. Chem. Solids, 1, 4, pp. 209-227, (1957); Bertotti G., Mayergoyz I.D., Serpico C., Spin-wave instabilities in large-scale nonlinear magnetization dynamics, Phys. Rev. Lett., 87, 21, (2001); Stancil D.D., Prabhakar A., Spin Waves: Theory and Applications, (2009)","V. Scalera; Department of Electrical Engineering and ICT, University of Naples Federico II, Naples, Italy; email: valentino.scalera@unina.it","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85099575744" +"Bendra M.; Ender J.; Fiorentini S.; Hadamek T.; De Orio R.L.; Goes W.; Sverdlov V.; Selberherr S.","Bendra, M. (57320954500); Ender, J. (57211467647); Fiorentini, S. (57211477066); Hadamek, T. (57321034300); De Orio, R.L. (55667231400); Goes, W. (55884148500); Sverdlov, V. (8908640600); Selberherr, S. (8840302400)","57320954500; 57211467647; 57211477066; 57321034300; 55667231400; 55884148500; 8908640600; 8840302400","Finite Element Method Approach to MRAM Modeling","2021","2021 44th International Convention on Information, Communication and Electronic Technology, MIPRO 2021 - Proceedings","","","","70","73","3","1","10.23919/MIPRO52101.2021.9597194","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85123048110&doi=10.23919%2fMIPRO52101.2021.9597194&partnerID=40&md5=8990b609c15f18d287420085865c98e6","Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; Institute for Microelectronics, TU Wien, Vienna, 1040, Austria; Silvaco Europe Ltd., Cambridge, United Kingdom","Bendra M., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; Ender J., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; Fiorentini S., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; Hadamek T., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; De Orio R.L., Institute for Microelectronics, TU Wien, Vienna, 1040, Austria; Goes W., Silvaco Europe Ltd., Cambridge, United Kingdom; Sverdlov V., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic; Selberherr S., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic","Spin-transfer torque magnetoresistive random access memory (STT-MRAM) is among the most promising candidates for emerging memories. Thus, reliable simulation tools are mandatory to provide an important aid for understanding and improving the design of such devices. In this work we are concerned with the simulation of STT-MRAM. The well-known Landau-Lifshitz-Gilbert (LLG) equation describes the magnetization dynamics. Since we are dealing with STT-MRAM, an additional torque term must be added to the LLG equation. The torque acting on the magnetization is generated by the nonequilibrium spin accumulation due to the electric current flowing through the structure. The partial differential LLG equation with the additional torque computed from the spin accumulation is solved using the highly efficient finite element method (FEM). We implemented several time integration schemes using an open-source FEM library. In order to verify and calibrate the FEM implementation, we compared it to a finite difference method (FDM) implementation used as a reference. By properly tailoring the time integration scheme and the time step size, almost identical simulation results as with the FDM are achieved. Proper calibration is essential in order to simulate a more realistic multi-layer structure with a composite switching layer consisting of ferromagnetic layers separated by nonmagnetic buffers. © 2021 Croatian Society MIPRO.","finite element method; LLG; Micromagnetics; spin-transfer torque; STT-MRAM","Finite difference method; Magnetic recording; Magnetization; Microelectronics; MRAM devices; Torque; Finite-difference methods; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Method implementations; Micromagnetics; Spin transfer torque; Spin-accumulations; Spin-transfer torque magnetoresistive random access memory; Time-integration scheme; Finite element method","","","","","Österreichische Nationalstiftung für Forschung, Technologie und Entwicklung; Christian Doppler Forschungsgesellschaft, CDG; Bundesministerium für Digitalisierung und Wirtschaftsstandort, BMDW","The financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development and the Christian Doppler Research Association is gratefully acknowledged.","Kolev T., Dobrev V., MFEM: Modular Finite Element Methods Library, (2010); Jinnai B., Igarashi J., Watanabe K., Funatsu T., Sato H., Fukami S., Ohno H., High-performance shape-Anisotropy magnetic tunnel junctions down to 2.3 nm, Ieee International Electron Devices Meeting (IEDM), pp. 2461-2464, (2020); Sloczewski J.C., Currents, torques, polarization factors in magnetic tunnel junctions, Physical Review B, 71, (2004); Abert C., Ruggeri M., Bruckner F., Vogler C., Hrkac G., Praetorius D., Et al., A three-dimensional spin-diffusion model for micromagnetics, Scientific Reports, 5, (2015); Lepadatu S., Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver, Scientific Reports, 7, (2017); Brunotte X., Meunier G., Imhoff J.-F., Finite element modeling of unbounded problems using transformations: A rigorous, powerful and easy solution, Ieee Transactions on Magnetics, 28, 2, pp. 1663-1666, (1992); Henrotte F., Meys B., Hedia H., Dular P., Legros W., Finite element modelling with transformation techniques, Ieee Transactions on Magnetics, 35, 3, pp. 1434-1437, (1999); Chen Q., Konrad A., A review of finite element open boundary techniques for static and quasi-static electromagnetic field problems, Ieee Transactions on Magnetics, 33, 1, pp. 663-676, (1997); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetizing fields, Ieee Transactions on Magnetics, 26, 2, pp. 415-417, (1990); Abert C., Exl L., Selke G., Drews A., Schrefl T., Numerical methods for the stray-field calculation: A comparison of recently developed algorithms, Journal of Magnetism and Magnetic Materials, 326, pp. 176-185, (2013); Abert C., Micromagnetics and spintronics: Models and numerical methods, The European Physical Journal B, 92, 6, pp. 1-45, (2019); Schoberl J., Netgen an advancing front 2d/3d-mesh generator based on abstract rules, Computing and Visualization in Science, 1, pp. 41-52, (1997)","","Koricic M.; Skala K.; Car Z.; Cicin-Sain M.; Babic S.; Sruk V.; Skvorc D.; Ribaric S.; Jerbic B.; Gros S.; Vrdoljak B.; Mauher M.; Tijan E.; Katulic T.; Petrovic J.; Grbac T.G.; Fijan N.F.; Gradisnik V.","Institute of Electrical and Electronics Engineers Inc.","Ericsson Nikola Tesla; et al.; Hrvatska Elektroprivreda; Koncar - Electrical Industry; Siemens Energy; Storm Computers","44th International Convention on Information, Communication and Electronic Technology, MIPRO 2021","27 September 2021 through 1 October 2021","Opatija","174235","","978-953233101-1","","","English","Int. Conv. Inf., Commun. Electron. Technol., MIPRO - Proc.","Conference paper","Final","","Scopus","2-s2.0-85123048110" +"Jiang J.; Cao Y.; Luo Z.; Cai W.; Wang J.; Cheng T.","Jiang, Jinbo (57211817480); Cao, Yu (57846112400); Luo, Zheng (57846774600); Cai, Wanchen (57845452400); Wang, Jiadong (57846112500); Cheng, Tingqiang (57846999200)","57211817480; 57846112400; 57846774600; 57845452400; 57846112500; 57846999200","Simulation research on pulse steepening technology based on ferrite transmission line; [基于铁氧体传输线的脉冲陡化技术仿真研究*]","2022","Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams","34","9","095005","","","","1","10.11884/HPLPB202234.220092","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85140055512&doi=10.11884%2fHPLPB202234.220092&partnerID=40&md5=2968435d6393b2df8bfe42e4ccfedf6a","Hubei Provincial Engineering Research Center for Power Transmission Line, China Three Gorges University, Yichang, 443002, China; College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China","Jiang J., Hubei Provincial Engineering Research Center for Power Transmission Line, China Three Gorges University, Yichang, 443002, China, College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China; Cao Y., College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China; Luo Z., College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China; Cai W., College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China; Wang J., College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China; Cheng T., College of Engineering and New Energy, China Three Gorges University, Yichang, 443002, China","The pulse steepening technology of ferrite transmission lines can realize high-frequency and high-power fast front pulse output and has the advantages of solid-state and compactness. It has been widely used in high-power microwave sources. The simulation calculation of pulse steepening characteristics of ferrite transmission lines lacks a more accurate model. Therefore, this paper establishes the simulation model of the ferrite transmission line by using COMSOL simulation software, considering the interaction between electromagnetic wave propagation and magnetic core magnetization precession. The Maxwell equation and Landau-Lifshitz-Gilbert (LLG) equation are combined for simulative calculation. Compared with the experimental results, the accuracy of the simulation model is verified. Based on this model, simultaneous interpreting of the effect of different transmission line lengths, voltage amplitude, and external bias magnetic field on pulse waveform is studied. The results show that the pulse front decreases with the increase of transmission line length and the increase of voltage amplitude; The output of the minimum pulse front can be realized by selecting an appropriate external bias magnetic field. © 2022 Editorial Office of High Power Laser and Particle Beams. All rights reserved.","COMSOL; ferrite transmission line; LLG equation; Maxwell equation; pulse front steepening","","","","","","","","French D M, Hoff B W., Spatially dispersive ferrite nonlinear transmission line with axial bias, IEEE Transactions on Plasma Science, 42, 10, pp. 3387-3390, (2014); Romanchenko I V, Rostov V V, Gunin A V, Et al., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, Journal of Applied Physics, 117, (2015); Reale D V, Parson J M, Neuber A A, Et al., Investigation of a stripline transmission line structure for gyromagnetic nonlinear transmission line high power microwave sources, Review of Scientific Instruments, 87, (2016); Ulmaskulov M R, Mesyats G A, Sadykova A G, Et al., Energy compression of nanosecond high-voltage pulses based on two-stage hybrid scheme, Review of Scientific Instruments, 88, (2017); Katayev I G., Electromagnetic shock waves, (1923); Pouladian-Kari R, Benson T M, Shapland A J, Et al., The electrical simulation of pulse sharpening by dynamic lines[C], Proceedings of the 7th Pulsed Power Conference, (1989); Dolan J E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, Journal of Physics D: Applied Physics, 32, 15, pp. 1826-1831, (1999); Yu Jianguo, Research of pulse sharpening based on ferrite line, pp. 9-13, (2010); Qiao Zhongxing, Liu Kai, Dong Yin, Investigation of ferrite-filled coaxial transmission lines for pulse sharpening, Transactions of China Electrotechnical Society, 30, s2, pp. 21-25, (2015); Zhang Xingjia, Lu Yanlei, Fan Yajun, Et al., Triple transmission line type subnanosecond pulse-compression device, High Power Laser and Particle Beams, 29, (2017); Tie Weihao, Meng Cui, Zhao Chengguang, Et al., Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application, Plasma Science and Technology, 21, (2019); Tie Weihao, Zhao Chengguang, Meng Cui, Et al., Numerical analysis on modulated RF pulse characteristics of gyro-magnetic nonlinear transmission line, High Voltage Engineering, 45, 1, pp. 301-309, (2019); Greco A F G, Rossi J O, Yamasaki F S, Et al., 1D-FDTD simulation of microwave generation using ferrite electromagnetic shock lines, Proceedings of 2020 IEEE Electrical Insulation Conference (EIC), (2020); Fang Xu, Pan Yafeng, Ding Zhenjie, Et al., Pulse sharpening effect of nonlinear ferrite-loaded transmisstion line, High Power Laser and Particle Beams, 26, (2014); Hu Yuechuan, The magnetization dynamics in magnetic nanotubes, pp. 3-9, (2016); Wan Defu, Ma Xinglong, Magnetic physics, pp. 437-441, (1994); Gilbert T L., A phenomenological theory of damping in ferromagnetic materials, IEEE Transactions on Magnetics, 40, 6, pp. 3443-3449, (2004)","J. Jiang; Hubei Provincial Engineering Research Center for Power Transmission Line, China Three Gorges University, Yichang, 443002, China; email: jinbojiang@163.com","","Editorial Office of High Power Laser and Particle Beams","","","","","","10014322","","QYLIE","","Chinese","Qiangjiguang Yu Lizishu","Article","Final","","Scopus","2-s2.0-85140055512" +"Ávila-Crisóstomo C.E.; Pal U.; Pérez-Rodríguez F.; Shelyapina M.G.; Shmyreva A.A.","Ávila-Crisóstomo, C.E. (57202575612); Pal, Umapada (55399738300); Pérez-Rodríguez, F. (7004480201); Shelyapina, M.G. (6602142844); Shmyreva, A.A. (57130908700)","57202575612; 55399738300; 7004480201; 6602142844; 57130908700","Local-field effect on the hybrid ferromagnetic-diamagnetic response of opals with Ni nanoparticles","2020","Journal of Magnetism and Magnetic Materials","514","","167102","","","","3","10.1016/j.jmmm.2020.167102","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85087402060&doi=10.1016%2fj.jmmm.2020.167102&partnerID=40&md5=6dda5afaab5e6332dad93a0e84a68f4b","Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo.Postal J-48, Puebla, 72570, Pue, Mexico; Saint-Petersburg State University, 7/9 Universitetskaya nab, St.Petersburg, 199034, Russian Federation; Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic","Ávila-Crisóstomo C.E., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo.Postal J-48, Puebla, 72570, Pue, Mexico; Pal U., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo.Postal J-48, Puebla, 72570, Pue, Mexico; Pérez-Rodríguez F., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo.Postal J-48, Puebla, 72570, Pue, Mexico; Shelyapina M.G., Saint-Petersburg State University, 7/9 Universitetskaya nab, St.Petersburg, 199034, Russian Federation; Shmyreva A.A., Saint-Petersburg State University, 7/9 Universitetskaya nab, St.Petersburg, 199034, Russian Federation, Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic","The magnetic properties of artificial opals infiltrated with nickel nanoparticles are studied both experimentally and theoretically. The response of the composite has a dominating ferromagnetic behavior at low magnitude fields (below the saturation region), then it is followed by a dominating diamagnetic one as the intensity of the external applied field is increased. These characteristics are not observed in most cases due to the low magnetic response of the elements involved. Diamagnetism in the artificially synthesized opals was observed, having a negative volume magnetic susceptibility of the order of 10−5. Also theoretical calculations were performed on the basis of the Landau-Lifshitz-Gilbert (LLG) equation, taking into account the diamagnetic response of the host material. Results obtained show the importance of the local magnetic field on the ferromagnetic nanoparticles, as well as the importance of the nature of the magnetic response of SiO2 spheres, which aligns in the opposite direction of the external applied field. © 2020 Elsevier B.V.","Ferromagnetism; Nanocomposite; Nanoparticles; Opal","Diamagnetism; Ferromagnetic materials; Ferromagnetism; Magnetic susceptibility; Nanoparticles; Nickel; Silica; Silicate minerals; SiO2 nanoparticles; Diamagnetic response; Ferromagnetic behaviors; Ferromagnetic nanoparticles; Landau-Lifshitz-Gilbert equations; Local magnetic field; Local-field effects; Nickel nanoparticles; Theoretical calculations; Nanomagnetics","","","","","PRODEP; VIEP-BUAP; Saint Petersburg State University, SPbU","This work was partially supported by PRODEP, PFCE, and VIEP-BUAP. The NMR studies were carried out at the Centre for Magnetic Resonance of the Research Park of Saint Petersburg State University.","Hultman L.O., Jack A.G., Soft magnetic composites-Materials and Applications, Electric Machines and Drives Conference, 2003. IEMDC’03. IEEE International, 1, pp. 516-522, (2003); Shen L.C., Liu C., Korringa J., Dunn K.J., Computation of conductivity and dielectric constant of periodic porous media, J. Appl. Phys., 67, 11, pp. 7071-7081, (1990); Purushotham S., Ramanujan R.V., Thermoresponsive magnetic composite nanomaterials for multimodal cancer therapy, Acta Biomater., 6, pp. 502-510, (2010); Lei H., Et al., The preparation and catalytically active characterization of papain immobilized on magnetic composite microspheres, Enzyme Microb. Technol., 35, pp. 15-21, (2004); Zou J., Et al., Thermally tuning of the photonic band gap of SiO2 colloid crystal infilled with ferroelectric BaTiO3, Appl. Phys. Lett., 78, 5, pp. 661-663, (2001); Miguez H., Et al., Face centered cubic photonic bandgap materials based on opal-semiconductor composites, J. Lightwave Technol., 17, 11, pp. 1975-1981, (1999); Bogomolov V.N., Et al., (1998); Balakirev V.G., Et al., Three-dimensional superlattices in opals, Crystallogr. Rep., 38, 3, pp. 348-353, (1993); Luo J., Chu W., Sall S., Petit C., Facile synthesis of monodispersed Au nanoparticles-coated on Stöber silica, Colloids Surf. A Physicochem. Eng. Asp., 425, pp. 83-91, (2013); Yu X., Lee Y., Frstenberg R., White J.O., Braun P.V., Filling fraction dependent properties of inverse opal metallic photonic crystals, Adv. Mater., 19, pp. 1689-1692, (2007); Mitsuteru I., Uchida H., Nishimura K., Lim P.B., Magnetophotonic crystals—a novel magneto-optic material with artificial periodic structures, J. Mater. Chem., 16, pp. 678-684, (2006); Inoue M., Et al., Magnetophotonic crystals, J. Phys. D: Appl. Phys., 39, pp. R151-R161, (2006); Ustinov V., Rinkevich A., Perov D., Samoilovich M., Klescheva S., Anomalous magnetic antiresonance and resonance in ferrite nanoparticles embedded in opal matrix, J. Magn. Magn. Mater., 324, 1, pp. 78-82, (2012); Carmona-Carmona A.J., Et al., Synthesis and characterization of magnetic opal/Fe3O4 colloidal crystall, J. Cryst. Growth, 462, pp. 6-11, (2017); Miguez H., Et al., Control of the photonic crystal properties of the fcc-packed submicrometer SiO2 spheres by sintering, Adv. Mater., 10, 6, pp. 480-483, (1998); Fang M., Volotinen T.T., Kulkarni S.K., Belova L., Rao K.V., Effect of embedding Fe3O4 nanoparticles in silica spheres on the optical transmission properties of three-dimensional magnetic photonic crystals, J. Appl. Phys., 108, pp. 1-6, (2010); Chabanenko V., Et al., The magnetic properties of C-Ni carbon-metal complexes, Low Temp. Phys., 43, 5, pp. 625-630, (2017); Bhatta H.L., Aliev A.E., Drachev V.P., New mechanism of plasmons specific for spin-polarized nanoparticles, Sci. Rep., 9, pp. 1-8, (2019); Stober W., Fink A., Bohn E., Controlled growth of monodisperse silica spheres in the micron size range, J. Colloid Interface Sci., 26, pp. 62-69, (1968); Santamaria-Razo D., Et al., A version of stober synthesis enabling the facile prediction of silica nanospheres size for the fabrication of opal photonic crystals, J. Nanopart. Res., 10, pp. 1225-1229, (2008); Ni P., Dong P., Cheng B., Li X., Zhang D., Synthetic SiO2 opals, Adv. Mater., 13, 6, pp. 437-441, (2001); Mayoral R., Et al., 3d long-range orderingrange ordering in an SiO2 submicrometer-sphere sintered superstructure, Adv. Matter., 9, 3, pp. 257-260, (1997); Eliseev A.A., Et al., Determination of the real structure of artificial and natural opals on the basis of three dimensional reconstructions of reciprocal space, JETP Lett., 90, 4, pp. 273-277, (2009); Cheng B., Et al., More direct evidence of the fcc arrangement for artificial opal, Opt. Commun., 170, pp. 41-46, (1999); Woodcock L.V., Entropy between the face-centered cubic and hexagonal close-packed crystal structures, Nature, 385, 9, pp. 141-143, (1997); Hou Y., Kondoh H., Ohta T., Gao S., Size-controlled synthesis of nickel nanoparticles, App. Surf. Sci., 241, pp. 218-222, (2005); Zach M., Penner R.M., Nanocrystalline nickel nanoparticles, Adv. Mater., 12, 12, pp. 878-883, (2000); Chen S.L., Dong P., Yang G.H., The size dependence of growth rate of monodisperse silica particles from tetraalkoxysilane, J. 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Jpn., 54, pp. 1537-1542, (1985); Bastow T.J., Trinchi A.; Mikhalev K.N., Germov A.Y., Prokopyev D.A., Uimin M.A., Yermakov A.Y., Konev A.S., Gaviko V.S., Novikov S.I., NMR study of magnetic nanoparticles Ni@C, J. Phys. Conf. Ser., 1389, 12137, pp. 1-5, (2019); Masalov V., Sukhinina N.S., Kudrenko E.A., Emelchenko G.A., Mechanism of formation and nanostructure of Stöber silica particles, Nanotechnology, 22, pp. 1-9, (2011); Avila-Crisostomo C.E., Sanchez-Mora E., Garcia-Vazquez V., Perez-Rodriguez F., Magnetic response of Fe nanoparticles embedded in artificial SiO2 opals, J. Magn. Magn. Mater., 465, pp. 252-259, (2018); Kittel C., Introduction to Solid State Physics, (1995); Hallouet B., Wetzel B., Pelster R., On the dielectric and magnetic properties of nanocomposites, J. Nanomater., 2007, pp. 1-11, (2007); Chang H.M., Liao C., A Parallel Derivation to the Maxwell-Garnett Formula for the Magnetic Permeability of Mixed Materials, WJCMP, 1, pp. 55-58, (2011); Bordianu A., Petrescu L., Ionita V., Numerical testing of homogenization formulas efficiency for magnetic composite materials, J. Phys.: Conf. Ser., 585, pp. 1-9, (2015); Jackson J.D., Classical Electrodynamics, (1962); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. der Sow., 8, pp. 153-169, (1935); Dudek M.R., Guskos N., Grabiec B., Maryniak M., Magnetization dynamics in Landau–Lifshitz–Gilbert formulation. FMR experiment modeling, J. Non-Cryst. Solids, 354, pp. 4146-4150, (2008); Jung S., Ketterson J.B., Chandrasekhar V., Micromagnetic calculations of ferromagnetic resonance in submicron ferromagnetic particles, Phys. Rev. B, 66, pp. 1-4, (2002); Shampine L.F., Witt A., A simple step size selection algorithm for ode codes, J. Comput. Appl. Math., 58, pp. 345-354, (1995); Barnett S.J., Kenny G.S., Gyromagnetic ratios of iron, cobalt, and many binary alloys of iron, cobalt, and nickel, Phys. Rev., 87, 5, pp. 723-734, (1952)","C.E. Ávila-Crisóstomo; Instituto de Física, Benemérita Universidad Autónoma de Puebla, Puebla, Apdo.Postal J-48, 72570, Mexico; email: cavila@ifuap.buap.mx","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85087402060" +"Barwal V.; Gupta N.K.; Hait S.; Husain S.; Behera N.; Chaudhary S.","Barwal, Vineet (57194472257); Gupta, Nanhe Kumar (59091144800); Hait, Soumyarup (57208802272); Husain, Sajid (57190069963); Behera, Nilamani (55619597000); Chaudhary, Sujeet (7102053581)","57194472257; 59091144800; 57208802272; 57190069963; 55619597000; 7102053581","Anisotropic gilbert damping in B2 ordered full heusler alloy Co2MnAl thin films","2020","AIP Conference Proceedings","2265","","030574","","","","1","10.1063/5.0017134","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85096549488&doi=10.1063%2f5.0017134&partnerID=40&md5=79678e451aa7dd9bfe3958110d1afb01","Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India; Ångström Laboratory, Department of Engineering Sciences, Box 534, Uppsala, SE-751 21, Sweden","Barwal V., Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India; Gupta N.K., Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India; Hait S., Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India; Husain S., Ångström Laboratory, Department of Engineering Sciences, Box 534, Uppsala, SE-751 21, Sweden; Behera N., Ångström Laboratory, Department of Engineering Sciences, Box 534, Uppsala, SE-751 21, Sweden; Chaudhary S., Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India","Structural and dynamic magnetization properties of Co2MnAl (CMA) full Heusler alloy thin films grown on Si (100) substrate at different substrate temperatures (Ts) 30°C, 200°C, 300°C, 400°C and 500°C are investigated. XRD patterns revealed the formation of B2 partially ordered phase at Ts=200°C and above. Ferromagnetic Resonance (FMR) technique have been used to determine the damping constant (α), resonance field (Hr) and line width (ΔH) of recorded spectra and fitted by using Landau-Lifshitz-Gilbert (LLG) equation. The lowest damping constant was found to be 0.007±0.002 for the film grown at Ts=200°C. Films exhibit uniaxial magnetic anisotropy. Anisotropic damping constant α is calculated along the easy and hard axis. Along the two directions remarkable change (almost ~59%) in α is observed. © 2020 American Institute of Physics Inc.. All rights reserved.","","","","","","","University Grant Commission","One of the authors V.B. acknowledges University Grant Commission (UGC) for providing UGC-NET fellowship.","De Groot R.A., Mueller F.M., Van Engen P.G., Buschow K.H.J., Phys. Rev. Lett., 50, (1983); Galanakis I., Dederichs P.H., Papanikolaou N., Phys. Rev. B, 66, (2002); Kubler J., Fecher G.H., Felser C., Phys. Rev. B - Condens. Matter Mater. Phys., 76, (2007); Sakuraba Y., Nakata J., Oogane M., Kubota H., Ando Y., Sakuma A., Miyazaki T., Japanese J. Appl. Physics, Part 1 Regul. Pap. Short Notes Rev. Pap., 44, (2005); Oogane M., Kubota T., Naganuma H., Ando Y., J. Phys. D Appl. Phys., 48, (2015)","S. Chaudhary; Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India; email: sujeetc@physics.iitd.ac.in","Sharma V.K.; Prajapat C.L.; Yusuf S.M.","American Institute of Physics Inc.","","64th DAE Solid State Physics Symposium 2019, DAE-SSPS 2019","18 December 2019 through 22 December 2019","Jodhpur, Rajasthan","164824","0094243X","978-073542025-0","","","English","AIP Conf. Proc.","Conference paper","Final","","Scopus","2-s2.0-85096549488" +"Leble S.","Leble, S. (7003379945)","7003379945","Domain wall evolution at nanowires in terms of 3D LLG equation initial-boundary problem","2021","Nanosystems: Physics, Chemistry, Mathematics","12","1","","42","59","17","0","10.17586/2220-8054-2021-12-1-42-59","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85102678162&doi=10.17586%2f2220-8054-2021-12-1-42-59&partnerID=40&md5=7b9625dfeca8a18f83e6bb669114deac","Immanuel Kant Baltic Federal University, Kaliningrad, 236041, Russian Federation","Leble S., Immanuel Kant Baltic Federal University, Kaliningrad, 236041, Russian Federation","A theory of a domain wall creation and propagation is built on a linearized version of the transformed Landau-Lifshitz-Gilbert equation. The Lakshmanan-Nakamura stereo-graphic transform, after extra exponential transformation, and, next - linerization partially save information of the original nonlinearity that allows one to keep the domain wall dynamics, form and properties. For cylindrical-symmetric wire geometry, the conventional orthonormal Bessel basis, combined with projecting operators technique applied to subspaces of directed propagation of domain walls is constructed. The physically significant problems of the dynamics switching at points far and close from a wire ends are formulated and its solutions are presented in the frame of the Fourier method. Stationary solutions are found and the wall structure along the wire and propagation plots are drawn. © 2021, ITMO University. All rights reserved.","Domain wall creation; Initial-boundary problem; Lakshmanan-nakamura transform; Landau-lifshitz-gilbert equation; Nanowire magnetization dynamics","","","","","","","","Ipatov M., Zhukova V., Zvezdin A.K., Zhukov A., Mechanisms of the ultrafast magnetization switching in bistable amorphous microwires, J. Appl. Phys, 106, (2000); Chizhik A.A., Zhukov A., Gonzalez A., Stupakiewicz A., Control of reversible magnetization switching by pulsed circular magnetic field in glass-coated amorphous microwires, Applied Physics Letters, 112, 7, (2018); Stupakiewicz A., Chizhik A., Et al., Ultrafast Magnetization Dynamics in Metallic Amorphous Ribbons with a Giant Magnetoimpedance Response, Physical Review Applied, 13, (2020); Badarneh M.H.A.G., Kwiatkowski J., Bessarab P.F., Mechanisms of energy efficient magnetization switching in a bistable nanowire, Nanosystems: Physics, Chemistry, Mathematics, 11, 3, pp. 294-300, (2020); Rodioniova V., Zhukova M., Et al., The defects influence on domain wall propagation in bistable glass-coated microwires, Physica B, 407, pp. 1446-1449, (2012); Brown W.F., Micromagnetics, Domains, and Resonance, J. Appl. Phys, 106, (1959); Frenkel I., Dorfman J.N., Spontaneous and Induced Magnetisation in Ferromagnetic Bodies, Nature, 126, pp. 274-278, (1930); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, 153, pp. 101-114, (1935); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Schryer N.L., Walker L.R., The motion of 180° domain walls in uniform dc magnetic fields, J. Appl. Phys, 45, (1974); Vereshchagin M, Baraban I, Leble S., Rodionova V., Structure of head-to-head domain wall in cylindrical amorphous ferromagnetic microwire and a method of anisotropy coefficient estimation, Journal of Magnetism and Magnetic Materials, 504, (2020); Leble S., Waveguide Propagation of Nonlinear Waves, Impact of Inhomogeneity and Accompanying Effects, (2019); Varga R., Zhukov A., Et al., Fast magnetic domain wall in magnetic microwires, Phys. Rev. B, 74, (2006); Chizhik Al., Zhukov A., Gonzalez J., Stupakiewicz A., Basic study of magnetic microwires for sensor applications: Variety of magnetic structures, Journal of Magnetism and Magnetic Materials, 422, pp. 299-303, (2017); Omelyanchik A., Gurevich A., Et al., Ferromagnetic glass-coated microwires for cell manipulation, Journal of Magnetism and Magnetic Materials, 242-245, pp. 216-223, (2020); Amirov A., Baraban I., Panina L., Rodionova V., Direct Magnetoelectric Effect in a Sandwich Structure of PZT and Magnetostrictive Amorphous Microwires, Materials, 13, 4, (2020); Vazquez M., Magnetic Nano-and Microwires: Design, Synthesis, Properties and Applications, Woodhead Publishing Series in Electronic and Optical Materials, (2015); Lakshmanan M., The fascinating world of the Landau-Lifshitz-Gilbert equation: an overview, Phil. Trans. R. Soc. A, 369, pp. 1280-1300, (2011); Lakshmanan M., Nakamura K., Landau-Lifshitz Equation of Ferromagnetism: Exact Treatment of the Gilbert Damping, Phys. Rev. Lett, 53, (1984); Vereshchagin M., Structure of domain wall in cylindrical amorphous microwire, Physica B: Condensed Matter, 549, pp. 91-93, (2018); Janutka A., Gawronski P., Structure of magnetic domain wall in cylindrical microwire, IEEE Transactions on Magnetics, 51, 5, pp. 1-6, (2015); Huening F., Backes A., Direct observation of large Barkhausen jump in thin Vicalloy wires, IEEE Magnetics Letters, 11, (2020); Leble S., Practical Electrodynamics with Advanced Applications, (2020); Baraban I., Leble S., Panina L., Rodionova V., Control of magneto-static and-dynamic properties by stress tuning in Fe-Si-B amorphous microwires with fixed dimensions, Journal of Magnetism and Magnetic Materials, 477, pp. 415-419, (2019); Leble S.B., Rodionova V.V., Dynamics of Domain Walls in a Cylindrical Amorphous Ferromagnetic Microwire with Magnetic Inhomogeneities, Theor. Math. Phys, 202, pp. 252-264, (2020); Kerimov M.K., Studies on the zeros of Bessel functions and methods for their computation, Comput. Math. and Math. Phys, 54, pp. 1337-1388, (2014); Leble S., Perelomova A., Dynamical projectors method in hydro-and electrodynamics, (2018); Stano M., Fruchart O., Magnetic Nanowires and Nanotubes, Handbook of Magnetic Materials, (2018); Alam J., Bran C., Et al., Cylindrical micro and nanowires: Fabrication, properties and applications, Journal of Magnetism and Magnetic Materials, 513, (2020); Popov I.Y., On the possibility of magnetoresistance governed by light, Nanosystems: physics, chemistry, mathematics, 4, 6, pp. 795-799, (2013); Chizhik A., Gonzalez J., Zhukov A., Gawronski P., Study of length of domain walls in cylindrical magnetic microwires, Journal of Magnetism and Magnetic Materials, 512, (2020); Corte-Leon P., Gonzalez-Legarreta L., Et al., Controlling the domain wall dynamics in Fe-, Ni-and Co-based magnetic microwires, Journal of Alloys and Compounds, 834, (2020)","S. Leble; Immanuel Kant Baltic Federal University, Kaliningrad, 236041, Russian Federation; email: lebleu@mail.ru","","ITMO University","","","","","","22208054","","","","English","Nanosyst. Phys. Chem. Math.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85102678162" +"Ahsan J.U.; Singh H.","Ahsan, Junaid Ul (57644856000); Singh, Harkirat (55627877779)","57644856000; 55627877779","Atomistic simulation study of FeCo alloy nanoparticles","2022","Applied Physics A: Materials Science and Processing","128","5","443","","","","5","10.1007/s00339-022-05589-8","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85128930787&doi=10.1007%2fs00339-022-05589-8&partnerID=40&md5=173ddb8d2fc6dfa6bf78301a76ad839a","Department of Physics, National Institute of Technology Srinagar, Hazratbal, J&K, Srinagar, 190006, India","Ahsan J.U., Department of Physics, National Institute of Technology Srinagar, Hazratbal, J&K, Srinagar, 190006, India; Singh H., Department of Physics, National Institute of Technology Srinagar, Hazratbal, J&K, Srinagar, 190006, India","Alloy nanoparticles are a potential candidate for research among different types of nanoparticles, due to their simple synthesizing method, promising features and diverse applications. Here, we have studied truncated octahedron FeCo alloy nanoparticles using atomistic simulations. The work is carried in the framework of classical spin Hamiltonian. Monte-carlo method and Landau Lifshitz Gilbert (LLG) equation are employed for sampling of chosen atomistic system. In this study, it has been observed that magnetic ordering temperature in the FeCo alloy is dependent on the composition of alloy in addition to the size of the system. The magnetic ordering temperature is calculated for each composition and size. Moreover, switching of the magnetic field in the FeCo alloy is studied using the combination of classical spin Hamiltonian and LLG equation as a function of composition of alloy and temperature of system. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.","Alloy bimetallic nanoparticles; Atomistic simulations; Hysteresis; Magnetization","Cobalt alloys; Hamiltonians; Iron alloys; Monte Carlo methods; Nanomagnetics; Nanoparticles; Synthesis (chemical); Alloy bimetallic nanoparticle; Alloy nanoparticle; Atomistic simulations; Bimetallic nanoparticles; Classical spin Hamiltonians; Fe-Co alloy; Landau-Lifshitz-Gilbert equations; Magnetic ordering temperatures; Simple++; Simulation studies; Binary alloys","","","","","","","Toshima N., Yonezawa T., Bimetallic nanoparticles-novel materials for chemical and physical applications, New J. Chem., 22, 11, pp. 1179-1201, (1998); Schwarz K., Mohn P., Blaha P., Kubler J., Electronic and magnetic structure of BCC Fe-Co alloys from band theory, J. Phys. F: Met. Phys., 14, 11, (1984); Lezaic M., Mavropoulos P., Blugel S., First-principles prediction of high Curie temperature for ferromagnetic bcc-Co and bcc-FeCo alloys and its relevance to tunneling magnetoresistance, Appl. Phys. Lett., 90, 8, (2007); Hasegawa T., Niibori T., Takemasa Y., Oikawa M., Stabilisation of tetragonal FeCo structure with high magnetic anisotropy by the addition of V and N elements, Sci. Rep., 9, 1, pp. 1-9, (2019); Sundaram K., Dhanasekaran V., Mahalingam T., Structural and magnetic properties of high magnetic moment electroplated CoNiFe thin films, Ionics, 17, 9, pp. 835-842, (2011); Zhou D., Zhou M., Zhu M., Yang X., Yue M., Electrodeposition and magnetic properties of FeCo alloy films, J. Appl. Phys., 111, 7, (2012); Williams H.M., The application of magnetic nanoparticles in the treatment and monitoring of cancer and infectious diseases, Biosci. Horizons: Int. J. Stud. Res., 10, (2017); Sundar R.S., Deevi S.C., Soft magnetic FeCo alloys: alloy development, processing, and properties, Int. Mater. Rev., 50, 3, pp. 157-192, (2005); Hedayatnasab Z., Abnisa F., Daud W.M.A.W., Review on magnetic nanoparticles for magnetic nanofluid hyperthermia application, Mater. Des., 123, pp. 174-196, (2017); Habib A.H., Ondeck C.L., Chaudhary P., Bockstaller M.R., McHenry M.E., Evaluation of iron-cobalt/ferrite core-shell nanoparticles for cancer thermotherapy, J. Appl. Phys., 103, 7, (2008); Li Y.H., Li J.Y., Xu Y.J., Bimetallic nanoparticles as cocatalysts for versatile photoredox catalysis, EnergyChem, 3, 1, (2021); Binder K., Horbach J., Kob W., Paul W., Varnik F., Molecular dynamics simulations, J. Phys.: Condens. Matter, 16, 5, (2004); Hansson T., Oostenbrink C., van Gunsteren W., Molecular dynamics simulations, Curr. Opin. Struct. Biol., 12, 2, pp. 190-196, (2002); Ren H., Zhuang X., Rabczuk T., Dual-horizon peridynamics: a stable solution to varying horizons, Comput. Methods Appl. Mech. Eng., 318, pp. 762-782, (2017); Baumgartner A., Burkitt A.N., Ceperley D.M., de Raedt H., Ferrenberg A.M., Heermann D.W., Et al., The Monte Carlo Method in Condensed Matter Physics (, 71; Sanchez-De Jesus F., Bolarin-Miro A.M., Cortes Escobedo C.A., Torres-Villasenor G., Vera-Serna P., Structural analysis and magnetic properties of FeCo alloys obtained by mechanical alloying, J. Metallurgy, 2016, (2016); Karipoth P., Thirumurugan A., Joseyphus R.J., Synthesis and magnetic properties of flower-like FeCo particles through a one pot polyol process, J. Colloid Interface Sci., 404, pp. 49-55, (2013); Chaubey G.S., Barcena C., Poudyal N., Rong C., Gao J., Sun S., Liu J.P., Synthesis and stabilization of FeCo nanoparticles, J. Am. Chem. Soc., 129, 23, pp. 7214-7215, (2007); Zehani K., Bez R., Moscovici J., Mazaleyrat F., Mliki N., Bessais L., High magnetic moment of FeCo nanoparticles produced in polyol medium, IEEE Trans. Magn., 50, 4, pp. 1-5, (2014); Eriksson O., Bergman A., Bergqvist L., Hellsvik J., Atomistic Spin Dynamics: Foundations and Applications, (2017); Skubic B., Hellsvik J., Nordstrom L., Eriksson O., A method for atomistic spin dynamics simulations: implementation and examples, J. Phys.: Condens. Matter, 20, 31, (2008); Evans R.F., Fan W.J., Chureemart P., Ostler T.A., Ellis M.O., Chantrell R.W., Atomistic spin model simulations of magnetic nanomaterials, J. Phys.: Condens. Matter, 26, 10, (2014); Hinzke D., Nowak U., Monte Carlo simulation of magnetization switching in a Heisenberg model for small ferromagnetic particles, Comput. Phys. Commun., 121, pp. 334-337, (1999); Ellis M.O., Evans R.F., Ostler T.A., Barker J., Atxitia U., Chubykalo-Fesenko O., Chantrell R.W., The Landau-Lifshitz equation in atomistic models, Low Temp. Phys., 41, 9, pp. 705-712, (2015); Garcia-Palacios J.L., Lazaro F.J., Langevin-dynamics study of the dynamical properties of small magnetic particles, Phys. Rev. B, 58, 22, (1998); Mokkath J.H., Size and chemical order dependence of magnetic-ordering temperature and spin structure in Fe@ Ni and Ni@ Fe core-shell nanoparticles, Phys. Chem. Chem. Phys., 22, 11, pp. 6275-6281, (2020); Ahsan J.U., Singh H., Temperature dependent magnetization in Co@ Fe Nanoparticles, Physica B, 627, (2022); Cao L.F., Dan X.I.E., Guo M.X., Park H.S., Fujita T., Size and shape effects on Curie temperature of ferromagnetic nanoparticles, Trans. Nonferrous Metals Soc. China, 17, 6, pp. 1451-1455, (2007); Crangle J., Hallam G.C., The magnetization of face-centred cubic and body-centred cubic iron+ nickel alloys, Proc. Roy. Soc. Lond. Ser. A. Math. Phys. Sci., 272, 1348, pp. 119-132, (1963); Kakehashi Y., Hosohata O., Curie-temperature ”Slater-Pauling curve, Le Journal de Physique Colloques, 49, C8, pp. C8-C73, (1988); Takahashi C., Ogura M., Akai H., First-principles calculation of the Curie temperature Slater-Pauling curve, J. Phys.: Condens. Matter, 19, 36, (2007); Kneller E.F., Luborsky F.E., Particle size dependence of coercivity and remanence of single-domain particles, J. Appl. Phys., 34, 3, pp. 656-658, (1963)","J.U. Ahsan; Department of Physics, National Institute of Technology Srinagar, Srinagar, Hazratbal, J&K, 190006, India; email: ratherjunaid67@gmail.com","","Springer Science and Business Media Deutschland GmbH","","","","","","09478396","","APAMF","","English","Appl Phys A","Article","Final","","Scopus","2-s2.0-85128930787" +"Cao G.; Wang W.; Du A.","Cao, Guojia (57984663600); Wang, Wang (57211349477); Du, An (7006264005)","57984663600; 57211349477; 7006264005","Simulation of the AC susceptibility for a core–shell magnetic nanoparticle","2023","Journal of Magnetism and Magnetic Materials","565","","170144","","","","2","10.1016/j.jmmm.2022.170144","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85142853268&doi=10.1016%2fj.jmmm.2022.170144&partnerID=40&md5=3bc8b03a15b4d66a379a2fdf4ba27694","College of Science, Northeastern University, Shenyang, 110819, China; National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China","Cao G., College of Science, Northeastern University, Shenyang, 110819, China; Wang W., College of Science, Northeastern University, Shenyang, 110819, China; Du A., College of Science, Northeastern University, Shenyang, 110819, China, National Frontiers Science Center for Industrial Intelligence and Systems Optimization, Northeastern University, Shenyang, 110819, China","A core–shell structure magnetic nanoparticle model with Heisenberg exchange interaction and vertical surface anisotropy is established. The anisotropy of the internal spins is D1 and the anisotropy of the surface spins is D2, both along the z axis. The surface spins also have surface anisotropy D3, and the direction is along the particle radius. The dynamic process of spins in particle is described by Landau Lifshitz Gilbert (LLG) equation, and the AC susceptibility of the nanoparticle is calculated. It is found that in the absence of external DC magnetic field, with the change of surface vertical anisotropy of the shell, there may be a new resonance peak in the AC susceptibility of the system in addition to the two resonance peaks corresponding to core and shell anisotropies respectively. The contribution of surface spins to the resonance peaks of the system is analyzed. When the external magnetic field is applied along the z direction, it is found that with the increase of the external magnetic field, all resonance peaks move to the high frequency direction. However, when an external magnetic field is applied in a direction 4π/9 from the z axis, the positions of the resonance peaks are almost unchanged with the different DC fields increasing. When the angle between a DC field with a constant strength and the direction of z axis of the particle gradually increases, there are many resonance peaks in AC susceptibility, and all resonance peaks move to the low frequency direction. © 2022","AC susceptibility; Landau Lifshitz Gilbert (LLG) equation; Nanoparticle; Resonance","Anisotropy; Magnetic fields; Magnetic susceptibility; Nanomagnetics; Shells (structures); A.C. susceptibility; Core shell structure; Core-shell magnetic nanoparticles; DC field; External magnetic field; Frequency directions; Landau-Lifshitz-Gilbert equations; Resonance peak; Surface anisotropy; Surface spins; Resonance","","","","","Higher Education Discipline Innovation Project, (B16009)","This research was supported by the 111 Project (B16009).","Hossain M., Qin B., Synthesis, characterization, properties and applications of two dimensional magnetic materials., 42, (2022); Li Kun X.U., Junwei L.P., A review of magnetic ordered materials in biomedical field, Constructions, applications and prospects., 228, (2022); Zelenakova A., Zelenak V., Bednarcik J., Magnetic Properties of Fe@Pt Nanoparticles with Core/Shell Morphology, Acta Phys. Pol. A, 118, pp. 1002-1004, (2010); Jiang L., Wang Z., Geng D., Et al., Structure and electromagnetic properties of both regular and defective onion-like carbon nanoparticles, Carbon, 95, pp. 910-918, (2015); Feng Y., Li D.A., Jiang L., Et al., Interface transformation for enhanced microwave-absorption properties of core double-shell nanocomposites, J. Alloy. Compd., 694, pp. 1224-1231, (2017); Ionescu D., Kovaci M., Field control of multiferroic spherical core-shell nanocomposites with applications in microwave range, IOP Conference Series-Materials Science and Engineering., 95, (2015); Hua A.N., Pan D., Li Y., Et al., Fe3Si-core/amorphous-C-shell nanocapsules with enhanced microwave absorption, J. Magn. Magn. Mater., 471, pp. 561-567, (2019); Zhang X., Rao Y.I., Guo J., Et al., Multiple-phase carbon-coated FeSn2/Sn nanocomposites for high-frequency microwave absorption, Carbon, 96, pp. 972-979, (2016); pp. 2605-2611, (2017); Wei S., Wang X., Zhang B., Et al., Preparation of hierarchical core-shell C@NiCo2O4@Fe3O4 composites for enhanced microwave absorption performance, Chem. Eng. J., 314, pp. 477-487, (2017); pp. 1420-1425, (2017); Wei Y., Yue J., Tang X.-Z., Et al., Enhanced magnetic and microwave absorption properties of FeCo-SiO2 nanogranular film functionalized carbon fibers fabricated with the radio frequency magnetron method, Appl. Surf. Sci., 428, pp. 296-303, (2018); Zhang L., Liu L., Ishio S., Investigation of magnetic anisotropy and magnetization process of tetragonal distorted FeCo multilayer films, Mater. Lett., 160, pp. 238-241, (2015); Zeb F., Ishaque M., Nadeem K., Kamran M., Surface effects and spin glass state in Co3O4 coated MnFe2O4 nanoparticles, Mater. Res. Express, 5, (2018); Mu C.P., Wang W.W., Zhang B., Et al., Dynamic micromagnetic simulation of permalloy antidot array film, Physica B, 405, 5, pp. 1325-1328, (2010); Usov N.A., Serebryakova O.N., Magnetization reversal of thin ferromagnetic elements with surface anisotropy, J. Magn. Magn. Mater., 453, pp. 142-148, (2018); pp. 69-74, (2018); Feng X., Xiong G., Zhang X.I., Et al., Third-order nonlinear optical susceptibilities associated with intersubband transitions in CdSe/ZnS core–shell quantum dots, Physica B, 383, 2, pp. 207-212, (2006); Yoon J., You C.-Y., Jung M.-H., Dynamic susceptibility of thin films with perpendicular magnetic anisotropy, Curr. Appl Phys., 13, 8, pp. 1765-1768, (2013); XianYu Z.-N., An D.U., Dynamic susceptibility in torus nanoring with canted external DC magnetic field, J. Magn. Magn. Mater., 511, (2020); Aharoni A., Exchange resonance modes in aferromagnetic sphere, J. Appl. Phys., 69, (1991); Aharoni A., Effect of surface anisotropy on the exchange resonance modes, J. Appl. Phys., 81, (1997); Goupalov S.V., Mattis D.C., Magnetic susceptibilities of finite Ising chains in the presence of defect sites, Phys. Rev. B., 76, (2007); Bouhou S., Essaoudi I., Ainane A., Hysteresis loops and susceptibility of a transverse Ising nanowire, J. Magn. Magn. Mater., 324, (2012); Fernandez-Rossier J., Palacios J.J., Magnetism in Graphene Nanoislands, Phys. Rev. Lett., 99, (2007); Vernay F., Sabsabi Z., Kachkachi H., ac susceptibility of an assembly of nanomagnets: Combined effects of surface anisotropy and dipolar interactions, Phys. Rev. B., 90, (2014); McKeever C., Ogrin F.Y., Aziz M.M., Influence of surface anisotropy on exchange resonance modes in spherical shells, J. Phys. D-Appl. Phys., 51, (2018); Usov N.A., Ferromagnetic resonance in thin ferromagnetic film with surface anisotropy, J. Magn. Magn. Mater., 474, pp. 118-121, (2019); Wang W., An D.U., Simulation of the AC susceptibility for nano-ferromagnetic materials, Mater. Res. Express, 6, (2019); Jin H., Magnetic physics. Science Press. Beijing., 283, (2013)","A. Du; College of Science, Northeastern University, Shenyang, 110819, China; email: duan@mail.neu.edu.cn","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Review","Final","","Scopus","2-s2.0-85142853268" +"Daeng-Am W.; Chureemart P.; Rittidech A.; Atkinson L.J.; Chantrell R.W.; Chureemart J., jessada.c@msu.ac.th","Daeng-Am, W. (57210791901); Chureemart, P. (45860922800); Rittidech, A. (15048412600); Atkinson, L.J. (56439072300); Chantrell, R.W. (7102157314); Chureemart, J. (54390742500)","57210791901; 45860922800; 15048412600; 56439072300; 7102157314; 54390742500","Micromagnetic model of exchange bias: Effects of structure and AF easy axis dispersion for IrMn/CoFe bilayers","2020","Journal of Physics D: Applied Physics","53","4","045002","","","","4","10.1088/1361-6463/ab5490","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85077775206&doi=10.1088%2f1361-6463%2fab5490&partnerID=40&md5=7f61c0b610a05bbb8a2e236ad95ac037","Department of Physics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand; Department of Physics, University of York, York, YO10 5DD, United Kingdom","Daeng-Am W., Department of Physics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand; Chureemart P., Department of Physics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand; Rittidech A., Department of Physics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand; Atkinson L.J., Department of Physics, University of York, York, YO10 5DD, United Kingdom; Chantrell R.W., Department of Physics, University of York, York, YO10 5DD, United Kingdom; Chureemart J., jessada.c@msu.ac.th, Department of Physics, Faculty of Science, Mahasarakham University, Mahasarakham, 44150, Thailand","A micromagnetic model of an exchange bias bilayer is used to examine the impact of the physical structure and the easy axis dispersion of the antiferromagnetic (AF) layer on the exchange bias field (HEB) in an IrMn/CoFe system. Because of the different timescales, the magnetization dynamics of the IrMn and CoFe layers are modelled using respectively a kinetic Monte Carlo (kMC) approach and Landau-Lifshitz-Gilbert (LLG) equation. The easy axis dispersion is modelled using a Gaussian distribution. The calculations show that HEBincreases with increasing IrMn thickness and grain size, in agreement with experimental work. Moreover, the model allows the visualization of the switching process at the micromagnetic level to reveal the reversal mechanism. We find that the effect of AF easy axis distribution not only strongly affects the reduction of HEBbut also drives non-coherent behaviour in the reversal mechanism. This confirms that the easy axis distribution is an important factor with strong impact on the magnetic properties and exchange bias field of an exchange bias system. © 2019 IOP Publishing Ltd.","Easy axis distribution; Exchange bias field; Kinetic monte carlo; Landau-lifshitz-gilbert equation","Binary alloys; Cobalt alloys; Dispersions; Iron alloys; Manganese alloys; Monte Carlo methods; Antiferromagnetics; Easy axis; Exchange-bias fields; Kinetic Monte Carlo; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Micromagnetic modeling; Physical structures; Iridium alloys","","","","","Development and Promotion of Science and Technology Talents, (23/2557)","This work was supported by Development and Promotion of Science and Technology Talents (DPST) Research Grant No. 23/2557","Baibich M.N., Broto J.M., Fert A., Van Dau F.N., Petroff F., Etienne P., Creuzet G., Friederich A., Chazelas J., Phys. Rev. lett., 61, (1988); Dieny B., Speriosu V.S., Parkin S.S., Gurney B.A., Wilhoit D.R., Mauri D., Phys. Rev., 43, (1991); Nogues J., Schuller I.K., J. Magn. Magn. Mater., 192, pp. 203-232, (1999); Berkowitz A.E., Takano K., J. Magn. Magn. Mater., 200, pp. 552-570, (1999); Kiwi M., J. Magn. Magn. Mater., 234, pp. 584-595, (2001); O'grady K., Fernandez-Outon L.E., Vallejo-Fernandez G., J. Magn. Magn. Mater., 322, pp. 883-899, (2010); Meiklejohn W.H., Bean C.P., Phys. Rev., 102, (1956); Meiklejohn W.H., Bean C.P., Phys. Rev., 105, (1957); Vallejo-Fernandez G., Aley N.P., Fernandez-Outon L.E., O'Grady K., J. Appl. Phys., 104, (2008); Fulcomer E., Charap S.H., J. Appl. Phys., 43, pp. 4184-4190, (1972); Vallejo-Fernandez G., Kaeswurm B., Fernandez-Outon L.E., O'Grady K., IEEE Trans. Magn., 44, pp. 2835-2838, (2008); Vallejo-Fernandez G., Fernandez-Outon L.E., O'Grady K., J. Phys. D: Appl. Phys., 41, 11, (2008); De Haas O., Schafer R., Schultz L., Barholz K.U., Mattheis R., J. Magn. Magn. Mater., 260, pp. 380-385, (2003); Zhao T., Fujiwara H., Zhang K., Hou C., Kai T., Phys. Rev., 65, (2001); Geshev J., Pereira L.G., Schmidt J.E., Phys. Rev., 66, (2002); Driemeier C., Nagamine L.C.C.M., Schmidt J.E., Geshev J., J. Magn. Magn. Mater., 272, pp. E811-E812, (2004); Geshev J., Nicolodi S., Pereira L.G., Schmidt J.E., Skumryev V., Surinach S., Baro M.D., Phys. Rev., 77, (2008); Pogossian S., Spenato D., Dekadjevi D., Youssef J.B., Phys. Rev., 73, (2006); Hu Y., Shi F., Wu G.Z., Jia N., Liu Y., Du A., J. Phys. Soc. Japan, 82, (2013); Dekadjevi D., Jaouen T., Spenato D., Pogossian S., Youssef J.B., Eur. Phys. J., 80, pp. 121-125, (2011); Tarazona H., Tafur M., Quispe-Marcatoma J., Landauro C., Baggio-Saitovitch E., Schmool D., Physica, 567, pp. 11-16, (2019); De Siqueira J., da Silva O., Kern P., Gazola J., Carara M., Rigue J., J. Magn. Magn. Mater., 478, pp. 6-11, (2019); Stiles M.D., McMichael R.D., Phys. Rev., 63, (2001); Maitre A., Ledue D., Patte R., J. Magn. Magn. Mater., 324, pp. 403-409, (2012); Chantrell R.W., Walmsley N., Gore J., Maylin M., Phys. Rev., 63, (2000); Callen H.B., Callen E., J. Phys. Chem. Solids., 27, pp. 1271-1285, (1966); Craig B., Lamberton R., Johnston A., Nowak U., Chantrell R.W., O'Grady K., J. Appl. Phys., 103, (2008); El-Hilo M., Chantrell R.W., O'Grady K., J. Appl. Phys., 84, pp. 5114-5122, (1998); Pfeiffer H., Phys. Status Solidi, 118, pp. 295-306, (1990); Peng Y., Wu X., Pressesky J., Ju G., Scholz W., Chantrell R., J. Appl. Phys., 109, (2011); Vallejo-Fernandez G., Chapmam J.N., Appl. Phys. Lett., 94, (2009); Aley N.P., Kroeger R., Lafferty B., Agnew J., Lu Y., O'Grady K., IEEE Trans. Magn., 45, pp. 3869-3872, (2009); Imakita K., Tsunoda M., Takahashi M., J. Appl. Phys., 97, (2005); Morales R., Basaran A.C., Villegas J.E., Navas D., Soriano N., Mora B., Redondo C., Batlle X., Schuller I.K., Phys. Rev. lett., 114, (2015); Lee J., Kim S., Yoon C.S., Kim C.K., Park B.G., Lee T.D., J. Appl. Phys., 92, pp. 6241-6244, (2002); Rodriguez-Suarez R., Vilela-Leao L., Bueno T., Mendes J., Landeros P., Rezende S., Azevedo A., Appl. Phys. Lett., 100, (2012)","","","Institute of Physics Publishing","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85077775206" +"Greco A.F.G.; Rossi J.O.; Yamasaki F.S.; Barroso J.J.; Schamiloglu E.; Da Silva Neto L.P.","Greco, Ana Flavia Guedes (57196488042); Rossi, Jose Osvaldo (7202397572); Yamasaki, Fernanda Sayuri (49561878200); Barroso, Joaquim Jose (7103318266); Schamiloglu, Edl (7006390232); Da Silva Neto, Lauro Paulo (55505146900)","57196488042; 7202397572; 49561878200; 7103318266; 7006390232; 55505146900","1D-FDTD Simulation of Microwave Generation Using Ferrite Electromagnetic Shock Lines","2020","2020 IEEE Electrical Insulation Conference, EIC 2020","","","9158728","344","347","3","1","10.1109/EIC47619.2020.9158728","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85092175466&doi=10.1109%2fEIC47619.2020.9158728&partnerID=40&md5=8b0c13d2df23364eee9b756d3fa99b7b","Plasma Associated Laboratory, National Institute for Space Research, Sao Jose dos Campos, SP, Brazil; Technological Institute of Aeronautics, Division of Electronic Engineering, Sao Jose dos Campos, SP, Brazil; University of New Mexico, Electrical and Computer Engineering Department, Albuquerque, 87131, NM, United States; Technology and Science Institute, Federal University of Sao Paulo, Sao Jose dos Campos, SP, Brazil","Greco A.F.G., Plasma Associated Laboratory, National Institute for Space Research, Sao Jose dos Campos, SP, Brazil; Rossi J.O., Plasma Associated Laboratory, National Institute for Space Research, Sao Jose dos Campos, SP, Brazil; Yamasaki F.S., Plasma Associated Laboratory, National Institute for Space Research, Sao Jose dos Campos, SP, Brazil; Barroso J.J., Technological Institute of Aeronautics, Division of Electronic Engineering, Sao Jose dos Campos, SP, Brazil; Schamiloglu E., University of New Mexico, Electrical and Computer Engineering Department, Albuquerque, 87131, NM, United States; Da Silva Neto L.P., Technology and Science Institute, Federal University of Sao Paulo, Sao Jose dos Campos, SP, Brazil","Ferrite-charged nonlinear transmission lines (NLTLs) have been used as electromagnetic shock lines in applications that require pulses with extremely fast rise times. Subject to an intense external magnetic field (20-40 kA/m), these lines can generate microwave radiation generally in L-band (1-2 GHz) and are known in this case as nonlinear gyromagnetic lines. Due to its wide applicability in the RF area, such as electronic warfare (in defense) or high power beam modulators (in industry), there is growing interest in the study of these lines, especially using finite difference time domain (FDTD) simulations to predict some important line parameters, such as the rise time of the output pulse and the frequency generated. The FDTD method is based on the nonlinear behavior of the magnetic material that fills the line as the current pulse propagates, inducing RF oscillations due to the precession of the ferrite's magnetic moments, described mathematically by the Landau-Lifshitz-Gilbert equation (LLG). Thus, this work presents a one-dimensional numerical modeling and simulation (1D) study to describe the behavior of these lines, which operate in the TEM mode. The numerical simulations were obtained using the joint solution of the transmission line equations and the gyromagnetic LLG equation in the publicly available software OCTAVE. © 2020 IEEE.","gyromagnetic nonlinear transmission lines; numerical simulation; RF generation","Electric lines; Electronic warfare; Electronics industry; Ferrite; Finite difference time domain method; Magnetic materials; Magnetic moments; Numerical models; Transmissions; External magnetic field; FDTD simulations; Finite-difference time-domain simulation; Landau-Lifshitz-Gilbert equations; Model and simulation; Nonlinear behavior; Nonlinear transmission lines; Transmission line equations; Nonlinear equations","","","","","Air Force Office of Scientific Research, AFOSR, (FA 9550-18-1-0111, FA9550-19-1-0225); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES; Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, (305.338/2016-1)","ACKNOWLEDGMENT Author Ana Flavia Guedes Greco thanks CAPES and the U.S. Air Force Research Office of Scientific Research (SOARD/AFOSR contract no. FA 9550-18-1-0111) for funding and supporting this work. Co-author José Osvaldo Rossi also thanks to the support from CNPq through the PQ-2 scholarship under contract 305.338/2016-1. The work at the University of New Mexico was supported by AFOSR Grant FA9550-19-1-0225.","Rangel E.G.L., Rossi J.O., Barroso J.J., Yamasaki F.S., Schamiloglu E., Practical constraints on nonlinear transmission lines for rf generation, Ieee Trans. Plasma Sci., 47, 1, pp. 1000-1016, (2019); Romanchenko I.V., Rostov V.V., Gubanov V.P., Stepchenko A.S., Gunin A.V., Kurkan I.K., Repetitive sub-gigawatt rf source based on gyromagnetic nonlinear transmission line, Rev. Sci. Instrum., 83, (2012); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, J. Appl. Phys., 117, (2015); Bragg J.-W.B., Dickens J.C., Neuber A.A., Material selection considerations for coaxial, ferrimagnetic-based nonlinear transmission lines, J. Appl. Phys., 113, (2013); Dolan J.E., Simulation of ferrite-loaded coaxial lines, Electron. Lett., 29, pp. 762-763, (1993); Rossi J.O., Yamasaki F.S., Barroso J.J., Schamiloglu E., Hasar U.C., Operation analysis of a novel concept of rf source as gyromagnetic line, Proc. SBMO/IEEE MTT-S Int. Microw. Optoelectron. Conf. (IMOC), pp. 1-4, (2017); Dolan J.E., Simulation of shock waves in ferrite-loaded coaxial transmission lines with axial bias, J. Phys. D Appl. Phys., 32, pp. 1826-1831, (1999); Dolan J.E., Bolton H.R., Shock front development in ferrite-loaded coaxial lines with axial bias, Iee Proc.-Sci., Meas. Technol., 147, 5, pp. 237-242, (2000); Perks R.M., Dolan J.E., Modelling electromagnetic shock lines using finite difference time-domain (fdtd) and transmission line matrix (tlm)-Type models, Iee Symposium on Pulsed Power'99 (Digest No. 1999/030). IET., pp. 271-274, (1999); Sevgi L., Uluisik C.A., Matlab-based transmission-line virtual tool: Finite-difference time-domain reflectometer, Ieee Antennas Propag. Mag., 48, 1, pp. 141-145, (2006)","","","Institute of Electrical and Electronics Engineers Inc.","","2020 IEEE Electrical Insulation Conference, EIC 2020","22 June 2020 through 3 July 2020","Knoxville","162491","","978-172815485-5","","","English","IEEE Electr. Insul. Conf., EIC","Conference paper","Final","","Scopus","2-s2.0-85092175466" +"Fiorentini S.; Ender J.; Selberherr S.; Goes W.; Sverdlov V.","Fiorentini, Simone (57211477066); Ender, Johannes (57211467647); Selberherr, Siegfried (8840302400); Goes, Wolfgang (55884148500); Sverdlov, Viktor (8908640600)","57211477066; 57211467647; 8840302400; 55884148500; 8908640600","Spin Transfer Torque Evaluation Based on Coupled Spin and Charge Transport: A Finite Element Method Approach","2022","Proceedings of World Multi-Conference on Systemics, Cybernetics and Informatics, WMSCI","2","","","12","15","3","0","10.54808/WMSCI2022.02.12","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85146918317&doi=10.54808%2fWMSCI2022.02.12&partnerID=40&md5=d71a2a92fa1597f421395f630226dd7a","Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, the Institute for Microelectronics, TU Wien, Wien, 1040, Austria; Institute for Microelectronics, TU Wien, Wien, 1040, Austria; Silvaco Europe Ltd, Silvaco Technology Centre Compass Point St Ives, St Ives, PE27 5JL, United Kingdom","Fiorentini S., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, the Institute for Microelectronics, TU Wien, Wien, 1040, Austria; Ender J., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, the Institute for Microelectronics, TU Wien, Wien, 1040, Austria; Selberherr S., Institute for Microelectronics, TU Wien, Wien, 1040, Austria; Goes W., Silvaco Europe Ltd, Silvaco Technology Centre Compass Point St Ives, St Ives, PE27 5JL, United Kingdom; Sverdlov V., Christian Doppler Laboratory for Nonvolatile Magnetoresistive Memory and Logic, the Institute for Microelectronics, TU Wien, Wien, 1040, Austria","Emerging spin transfer torque magnetoresistive random access memories (STT MRAM) are nonvolatile and offer high speed and endurance. The MRAM cell necessarily includes a fixed reference magnetic layer and a free-to-switch ferromagnetic layer (FL). The layers are separated by a tunnel barrier. The FL usually consists of several sub-layers separated by nonmagnetic buffer layers. The magnetization dynamics of the FL is governed by the Landau-Lifshitz-Gilbert (LLG) equation supplemented with the corresponding torques. To accurately design MRAM cells it is necessary to evaluate the torques acting on the magnetization in composite magnetic layers. The torques depend on nonequilibrium spin accumulation generated by an electric current. The electric current and the spin accumulation also depend on the magnetization. Therefore, the LLG and the spin-charge transport equations are coupled and must be solved simultaneously. We apply the finite element method (FEM) to numerically solve this coupled system of partial differential equations. We follow a modular approach and use well-developed C++ FEM libraries. For the computation of the torques acting in a magnetic tunnel junction (MTJ), a magnetization-dependent resistivity of the tunnel barrier is introduced. A fully three-dimensional solution of the equations is performed to accurately model the torques acting on the magnetization. The use of a unique set of equations for the whole memory cell including the FL, fixed layer, contacts, and nonmagnetic spacers is an ultimate advantage of our approach. Copyright 2022 © by the International Institute of Informatics and Systemics. All rights reserved.","Finite Element Method; MRAM; Spin Accumulation; Spin and Charge Drift-diffusion; Spin Transfer Torque","Buffer layers; Magnetic recording; Magnetization; MRAM devices; Torque; Tunnel junctions; Charge drift; Drift diffusion; Ferromagnetic layers; Magnetic layers; MRAM; Spin and charge drift-diffusion; Spin drift; Spin transfer torque; Spin-accumulations; Tunnel barrier; Finite element method","","","","","Christian Doppler ResearchAssociationisgratefullyacknowledged; Österreichische Nationalstiftung für Forschung, Technologie und Entwicklung; Christian Doppler Forschungsgesellschaft, CDG; Bundesministerium für Digitalisierung und Wirtschaftsstandort, BMDW","Funding text 1: The financial support by the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development, and the Christian Doppler Research Association is gratefully acknowledged.; Funding text 2: ThefinancialsupportbytheAustrianFederalMinistryforDigital and Economic Affairs, the National Foundation for Research, Technology and Development, and the Christian Doppler ResearchAssociationisgratefullyacknowledged.","Iwasaki S., Perpendicular Magnetic Recording-Its Development and Realization, Proc. Jpn. Acad. Ser. B Phys. Biol. Sci, 85, pp. 37-54, (2009); Slonczewski J.C., Current-driven Excitation of Magnetic Multilayers, J. Magn. Magn. Mater, 159, pp. L1-L7, (1996); Berger L., Emission of Spin Waves by a Magnetic Multilayer Traversed by a Current, Phys. Rev.B, 54, pp. 9353-9358, (1996); Song Y.J., Lee J.H., Shin H.C., Et al., Highly Functional and Reliable 8Mb STT-MRAM Embedded in 28nm Logic, Proc. IEDM, pp. 663-666, (2016); Sato H., Honjo H., Watanabe T., Et al., 14ns Write Speed 128Mb Density Embedded STT-MRAM with Endurance >1010 and 10yrs Retention @85°C Using Novel Low Damage MTJ Integration Process, Proc. IEDM, pp. 608-611, (2016); Golonzka O., Alzate J.-G., Arslan U., Et al., MRAM as Embedded Non-volatile Memory Solution for 22FFL FinFET Technology, Proc. IEDM, pp. 412-415, (2018); Abert C., Ruggeri M., Bruckner F., Et al., A Three-Dimensional Spin-Diffusion Model for Micromagnetics, Sci. Rep, 5, (2015); Lepadatu S., Unified Treatment of Spin Torques Using a Coupled Magnetisation Dynamics and Three-dimensional Spin Current Solver, Sci. Rep, 7, (2017); Fiorentini S., Ender J., Mohamedou M., Et al., Computation of Torques in Magnetic Tunnel Junctions Through Spin and Charge Transport Modeling, Proc. SISPAD, pp. 209-212, (2020); Anderson R., Andrej J., Barker A., Et al., MFEM: A Modular Finite Element Methods Library, Comp. & Math. with App, 81, pp. 42-74, (2021); Zhang S., Levy P. M., Fert A., Mechanisms of Spin-polarized Current-driven Magnetization Switching, Phys. Rev. Lett, 88, (2022)","","Callaos N.C.; Gaile-Sarkane E.; Hashimoto S.; Sanchez B.","International Institute of Informatics and Cybernetics","International Institute of Informatics and Systemics (IIIS)","26th World Multi-Conference on Systemics, Cybernetics and Informatics, WMSCI 2022","12 July 2022 through 15 July 2022","Virtual, Online","181656","27710947","978-195049265-7","","","English","Proc. World Multi-Conf. Syst., Cybern. Informatics, WMSCI","Conference paper","Final","","Scopus","2-s2.0-85146918317" +"Zeng J.; Chen Y.; Liu J.; Huang C.; Xu N.; Li C.; Fang L.","Zeng, Junwei (57226718310); Chen, Yabo (57210175057); Liu, Jiahao (57200659054); Huang, Chenglong (57205738806); Xu, Nuo (57206132501); Li, Cheng (57198358372); Fang, Liang (55703008200)","57226718310; 57210175057; 57200659054; 57205738806; 57206132501; 57198358372; 55703008200","MESO Neuron: A Low-Power and Ultrafast Spin Neuron for Neuromorphic Computing","2022","IEEE Magnetics Letters","13","","4502605","","","","0","10.1109/LMAG.2022.3146130","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85124070005&doi=10.1109%2fLMAG.2022.3146130&partnerID=40&md5=f9498a12de93f4f4fdab4212cb3aaa4d","College Of Computing, National University Of Defense Technology, Changsha, 410073, China","Zeng J., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Chen Y., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Liu J., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Huang C., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Xu N., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Li C., College Of Computing, National University Of Defense Technology, Changsha, 410073, China; Fang L., College Of Computing, National University Of Defense Technology, Changsha, 410073, China","In this letter, a low-power and ultrafast spin neuron for mimicking biological neurons based on magneto-electric spin-orbit (MESO) neurons is presented. First, the physical model of a MESO neuron based on the Landau-Lifshitz-Gilbert (LLG) equation at room temperature is built for investigating the characteristics. By utilizing these characteristics of the MESO device, a current pulse is used to induce the stochastic switching behaviors. We successfully mimic the behavior of the biological neuron with single activation time down to 0.8 ns. Second, using model-derived device parameters, we further simulate a three-layer fully connected neural network using MESO neurons. Using the Mixed National Institute of Standards and Technology database handwritten pattern dataset, our system achieves a recognition accuracy of 98%. In addition, the influence of pulsewidth and amplitude on activation functions of MESO neurons is researched using HSPICE tools. The results show that as pulsewidth and amplitude are increasing, the power consumption and computing time increase while the energy consumption decreases. Specifically, the power consumption performance of a MESO neuron is about 10 μW and improved approximately three orders of magnitude compared to a 45 nm CMOS neuron. © 2010-2012 IEEE.","Magneto-electric coupling; Neuromorphic computing; Resistive crossbar network; Spin electronics; Spin neuron; Spin-orbit coupling","Character recognition; Chemical activation; Electric power utilization; Low power electronics; Network architecture; Neural networks; Stochastic systems; Crossbar networks; Magneto-mechanical effects; Magnetoelectric couplings; Magnetoelectrics; Neuromorphic computing; Neuromorphic engineering; Power demands; Resistive crossbar network; Spin neuron; Spin-orbit couplings; Neurons","","","","","National Natural Science Foundation of China, NSFC, (61832007); National Key Research and Development Program of China, NKRDPC, (2018YFB1003304)","This work was supported in part by the National Key Research Development Program of China under Grant 2018YFB1003304, and in part by the National Natural Science Foundation of China under Grant 61832007.","Andre C., Matsumoto R., Grollier J., Cros V., Anane A., Fert A., Khvalkovskiy A., Zvezdin K., Nishimura K., Nagamine Y., Maehara H., Tsunekawa K., Fukushima A., Yuasa S., Vertical current induced domain wall motion in MgO-based magnetic tunnel junction with low current densities, Nat. Phys., 7, pp. 626-630, (2011); Apalkov D., Dieny B., Slaughter J.M., Magnetoresistive random access memory, Proc. IEEE, 104, pp. 1796-1830, (2016); Bindal N., Kukarni A., Singh G., Kaushik B.K., Spin based neuromorphic computing, Proc. SPIE, (2019); Brataas A., Kent A., Ohno H., Current-induced torques in magnetic materials, Nat. Mater., 11, pp. 372-381, (2012); Camsari K.Y., Faria R., Sutton B.M., Datta S., Stochastic p-bits for invertible logic, Phys. Rev. X, 7, (2017); Cao Y., Rushforth A., Sheng Y., Zheng H., Wang K., Tuning a binary ferromagnet into a multistate synapse with spin-orbit-torque-induced plasticity, Adv. Funct. Mater., 29, (2019); Cao Y., Xing G., Lin H., Zhang N., Zheng H., Wang K., Prospect of spin-orbitronic devices and their applications, IScience, 23, (2020); Chabi D., Querlioz D., Zhao W., Klein J.-O., Robust learning approach for neuro-inspired nanoscale crossbar architecture, ACM J. Emerg. Technol. Comput. Syst., 10, pp. 1-20, (2014); Davies M., Srinivasa N., Lin T.-H., Chinya G., Cao Y., Choday S.H., Dimou G., Joshi P., Imam N., Jain S., Liao Y., Lin C.-K., Lines A., Liu R., Mathaikutty D., McCoy S., Paul A., Tse J., Venkataramanan G., Weng Y.-H., Wild A., Yang Y., Wang H., Loihi: A neuromorphic manycore processor with on-chip learning, IEEE Micro, 38, pp. 82-99, (2018); Deng J., Miriyala V.P.K., Zhu Z., Fong X., Liang G., Voltage-controlled spintronic stochastic neuron for restricted Boltzmann machine with weight sparsity, IEEE Electron Device Lett., 41, pp. 1102-1105, (2020); Duttagupta S., Kurenkov A., Tretiakov O.A., Krishnaswamy G., Sala G., Krizakova V., MacCherozzi F., Dhesi S., Gambardella P., Ohno H., Spin-orbit torque switching of an antiferromagnetic metallic heterostructure, Nat. Commun., 11, (2020); Fukami S., Zhang C., Dutta Gupta S., Kurenkov A.V., Ohno H., Magnetization switching by spin-orbit torque in an antiferromagnet-ferromagnet bilayer system., Nat. Mater., 15, pp. 535-541, (2016); Grollier J., Querlioz D., Stiles M.D., Spintronic nanodevices for bioinspired computing, Proc. IEEE, 104, pp. 2024-2039, (2016); Guo Z., Yin J., Bai Y., Zhu D., Shi K., Wang G., Cao K., Zhao W., Spintronics for energy-efficient computing: An overview and outlook, Proc. IEEE, 109, pp. 1398-1417, (2021); Hassan O., Faria R., Camsari K.Y., Sun J.Z., Datta S., Low-barrier magnet design for efficient hardware binary stochastic neurons, IEEE Magn. Lett., 10, (2019); Heron J., Chiang T., Magnetoelectrics and multiferroics: Materials and opportunities for energy-efficient spin-based memory and logic, MRS Bull., 46, pp. 938-945, (2021); Lan X., Cao Y., Liu X., Xu K., Liu C., Zheng H., Wang K., Gradient descent on multilevel spin-orbit synapses with tunable variations, Adv. Intell. 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Circuits Syst., 10, pp. 828-836, (2016); Zhang D., Zeng L., Zhang Y., Zhao W., Klein J.O., Stochastic spintronic device based synapses and spiking neurons for neuromorphic computation, Proc. IEEE/ACM Int. Symp. Nanoscale Architectures, pp. 173-178, (2016); Zhang S., Luo S., Xu N., Zou Q., Song M., Yun J., Luo Q., Guo Z., Li R., Tian W., Li X., Zhou H., Chen H., Zhang Y., Yang X., Jiang W., Shen K., Hong J., Yuan Z., Xi L., Xia K., Salahuddin S., Dieny B., You L., A spin-orbit-torque memristive device, Adv. Electron. Mater., 5, (2019); Zhong Y., Tang J., Li X., Gao B., Qian H., Wu H., Dynamic memristor-based reservoir computing for high-efficiency temporal signal processing, Nat. Commun., 12, pp. 1-9, (2021); Zhang X., Cai W., Wang M., Pan B., Cao K., Guo M., Zhang T., Cheng H., Li S., Zhu D., Wang L., Shi F., Du J., Zhao W., Spin-torque memristors based on perpendicular magnetic tunnel junctions for neuromorphic computing, Adv. Sci., 8, (2021); Zhao W.S., Agnus G., Derycke V., Filoramo A., Bourgoin J.-P., Gamrat C., Nanotube devices based crossbar architecture: Toward neuromorphic computing, Nanotechnol-ogy, 21, (2010); Zhao W., Portal J., Kang W., Moreau M., Zhang Y., Aziza H., Klein J.-O., Wang Z., Querlioz D., Deleruyelle D., Bocquet M., Ravelosona D., Muller C., Chappert C., Design and analysis of crossbar architecture based on complementary resistive switching non-volatile memory cells, J. Parallel Distrib. Comput., 74, pp. 2484-2496, (2014)","L. Fang; College Of Computing, National University Of Defense Technology, Changsha, 410073, China; email: lfang@nudt.edu.cn; C. Li; College Of Computing, National University Of Defense Technology, Changsha, 410073, China; email: mengchengli@yeah.net","","Institute of Electrical and Electronics Engineers Inc.","","","","","","1949307X","","","","English","IEEE Magn. Lett.","Article","Final","","Scopus","2-s2.0-85124070005" +"Kaneko T.; Honkura Y.; Honkura S.; Akagi F.","Kaneko, Terumi (57457773500); Honkura, Yoshinobu (55355192400); Honkura, Shinpei (57205653490); Akagi, Fumiko (6604097171)","57457773500; 55355192400; 57205653490; 6604097171","Effects of Fall Times of Pulse Currents on Output Voltages in Amorphous-Wire-Based Magnetic Sensors","2022","IEEE Transactions on Magnetics","58","8","4002405","","","","2","10.1109/TMAG.2022.3151390","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85124816778&doi=10.1109%2fTMAG.2022.3151390&partnerID=40&md5=a309fb174d648bbf78601afcabafff5a","Kogakuin University, Nishi-shinjuku, Electrical and Engineering and Electronics Program, School of Engineering, Tokyo, Shinjuku-ku, 163-8677, Japan; Magnedesign Company Ltd., Showaku, Nagoya-shi, Aichi, 466-0059, Japan; Nanocoil Company Ltd., Chita-gun, Aichi, 470-2102, Japan; Kogakuin University, Nishi-shinjuku, Department of Applied Physics, School of Advanced Engineering, Tokyo, Shinjuku-ku, 163-8677, Japan","Kaneko T., Kogakuin University, Nishi-shinjuku, Electrical and Engineering and Electronics Program, School of Engineering, Tokyo, Shinjuku-ku, 163-8677, Japan; Honkura Y., Magnedesign Company Ltd., Showaku, Nagoya-shi, Aichi, 466-0059, Japan; Honkura S., Nanocoil Company Ltd., Chita-gun, Aichi, 470-2102, Japan; Akagi F., Kogakuin University, Nishi-shinjuku, Electrical and Engineering and Electronics Program, School of Engineering, Tokyo, Shinjuku-ku, 163-8677, Japan, Kogakuin University, Nishi-shinjuku, Department of Applied Physics, School of Advanced Engineering, Tokyo, Shinjuku-ku, 163-8677, Japan","Micro-sized magnetic sensors with ultrahigh sensitivity are required in biomagnetic measuring devices. The gigahertz (GHz) spin rotation sensor, which is a coil-type magnetic sensor, shows high sensitivity while transmitting GHz-pulse currents. Detection magnetic fields are sensed via a pickup coil, which is wrapped around the wire when the GHz-pulse currents are applied. However, the micromechanism in the amorphous wire, which exhibits high sensitivity, has not yet been elucidated. In this study, we investigated how the fall time of the pulse current, which defines the frequency, affects the output peak voltages and the behavior of the magnetization inside the amorphous wire. We found that the shorter the fall time, the higher are the absolute values of the output peak voltage and the external magnetic field detecting those values. At a fall time of 0.385 ns, only the rotations of magnetization in the outer circumference of the amorphous wire contributed to the output voltages, and at a fall time of 5.0 ns, the domain wall motions inside the wire also contributed to the output voltages. This difference was the reason why the output peak voltages increased as the fall time was shortened. © 1965-2012 IEEE.","Amorphous wire; gigahertz spin rotation sensor (GSR sensor); Landau-Lifshitz-Gilbert (LLG) equation; magnetic sensor","Domain walls; Magnetic sensors; Magnetization; Spin dynamics; Wire; Amorphous wire; Fall time; Gigahertz spin rotation sensor; Gilbert equation; Landau–; Lifshitz–; Magnetic-field; Rotation sensor; Sensitivity; Spin-rotations; Magnetic fields","","","","","","","Phan M.-H., Peng H.-X., Giant magnetoimpedance materials: Fundamentals and applications, Prog. Mater. Sci., 53, 2, pp. 323-420, (2008); He D.F., Zhang Y.Z., Shiwa M., Moriya S., Development of eddy current testing system for inspection of combustion chambers of liquid rocket engines, Rev. Sci. Instrum., 84, 1, (2013); Devkota J., Ruiz A., Mukherjee P., Srikanth H., Phan M.-H., Magneto-impedance biosensor with enhanced sensitivity for highly sensitive detection of nanomag-D beads, IEEE Trans. Magn., 49, 7, pp. 4060-4063, (2013); Uchiyama T., Mohri K., Honkura Y., Panina L.V., Recent advances of pico-tesla resolution magneto-impedance sensor based on amorphous wire CMOS IC MI sensor, IEEE Trans. Magn., 48, 11, pp. 3833-3839, (2012); Sun N.X., Wang S.X., Silva T.J., Kos A.B., High-frequency behavior and damping of Fe-Co-N-based high-saturation soft magnetic films, IEEE Trans. Magn., 38, 1, pp. 146-149, (2002); Uchiyama T., Nakayama S., Magnetic sensors using amorphous metal materials: Detection of premature ventricular magnetic waves, Physiol. 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Status Solidi A, 206, 4, pp. 601-607, (2009); Jiles D.C., Recent advances and future directions in magnetic materials, Acta Mater., 51, 19, pp. 5907-5939, (2003); Zhukova V., Ipatov M., Zhukov A., Thin magnetically soft wires for magnetic microsensors, Sensors, 9, 11, pp. 9216-9240, (2009); Honkura Y., Honkura S., The development of a high sensitive micro size magnetic sensor named as GSR sensor excited by GHz pulse current, Proc. Prog. Electromagn. Res. Symp. (PIERS-Toyama), pp. 324-331, (2018); Honkura Y., Honkura S., The development ASIC type GSR sensor driven by GHz pulse current, Sensors, 20, 4, pp. 1-13, (2020); Akagi F., Ohta H., Ultra-high sensitivity magnetic impedance sensor by applying GHz pulse current, Proc. MMM, (2019); Mohri K., Humphrey F.B., Kawashima K., Kimura K., Mizutani M., Large Barkhausen and Matteucchi effects in FeCoSib, FeCrSib, and FeNiSiB amorphous wires, IEEE Trans. Mag., 26, 5, pp. 1789-1791, (1990); Vereshchagin M., Baraban I., Leble S., Rodionova V., Structure of head-to-head domain wall in cylindrical amorphous ferromagnetic microwire and a method of anisotropy coefficient estimation, J. Magn. Magn. Mater., 504, (2020)","T. Kaneko; Kogakuin University, Nishi-shinjuku, Electrical and Engineering and Electronics Program, School of Engineering, Shinjuku-ku, Tokyo, 163-8677, Japan; email: cm21011@ns.kogakuin.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85124816778" +"Choi B.C.; Jordan K.; Rudge J.; Speliotis T.","Choi, B.C. (7402755257); Jordan, K. (57216226833); Rudge, J. (12787134400); Speliotis, Th. (55885793800)","7402755257; 57216226833; 12787134400; 55885793800","Coherent Magnetization Dynamics in Ni80Fe20Thin Films Incorporated in Fe/Au Spintronic Terahertz Emitters","2021","IEEE Transactions on Magnetics","57","2","9139443","","","","0","10.1109/TMAG.2020.3009037","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85099748574&doi=10.1109%2fTMAG.2020.3009037&partnerID=40&md5=ecaf47803fb35073d22d0987e9c27146","Department of Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, BC, Canada; Institute of Materials Science, NCSR Demokritos, Agia Paraskevi, 153 10, Greece","Choi B.C., Department of Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, BC, Canada; Jordan K., Department of Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, BC, Canada; Rudge J., Department of Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, BC, Canada; Speliotis T., Institute of Materials Science, NCSR Demokritos, Agia Paraskevi, 153 10, Greece","Coherent magnetization dynamics at terahertz (THz) frequencies is achieved by directly incorporating ferromagnetic Ni80Fe20 thin films into Fe/Au bilayer spintronic THz emitters. Electrooptical (EO) sampling demonstrates a generation of THz pulses centered near 2.8 THz with a bandwidth in the 1-4 THz range. Ni80Fe20 magnetization is directly coupled to the magnetic component of the THz wave, in which the large-amplitude magnetization precession is found phase locked with the THz pulse. The THz-induced magnetization dynamics can be controlled by external bias magnetic fields. The micromagnetic and analytical models based on the Landau-Lifshitz-Gilbert (LLG) equation are in good agreement with experimental findings and verify that the underlying mechanism of the THz-induced magnetization dynamics is the Zeeman coupling between the magnetic component of the THz field and Ni80Fe20 magnetization. Our results open the opportunities for the use of low-cost metallic spintronic THz emitters in the studies of THz-induced magnetization dynamics in magnetic thin films. © 1965-2012 IEEE.","Electrooptical (EO) sampling; micromagnetic modeling; terahertz (THz) generation; time-resolved magneto-optical Kerr effect (TR-MOKE); ultrafast magnetization dynamics","Binary alloys; Dynamics; Gold alloys; Iron alloys; Magnetic devices; Magnetic thin films; Magnetization; Bias magnetic field; Induced magnetizations; Landau-Lifshitz-Gilbert equations; Magnetic components; Magnetization dynamics; Magnetization precession; Terahertz emitters; Terahertz frequencies; Terahertz waves","","","","","","","Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1-2, pp. L1-L7, (1996); Choi B.C., Rudge J., Girgis E., Kolthammer J., Hong Y.K., Lyle A., Spin-current pulse induced switching of vortex chirality in permalloy/Cu/Co nanopillar, Appl. Phys. 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Lett., 29, 15, pp. 1805-1807, (2004); Kampfrath T., Et al., Terahertz spin current pulses controlled by magnetic heterostructures, Nature Nanotechnol., 8, 4, pp. 256-260, (2013); Nahata A., Weling A.S., Heinz T.F., A wideband coherent terahertz spectroscopy system using optical rectification and electro-optic sampling, Appl. Phys. Lett., 69, pp. 2321-2323, (1996); Schlauderer S., Et al., Temporal and spectral fingerprints of ultrafast all-coherent spin switching, Nature, 569, pp. 383-387, (2019); Xu H., Hajisalem G., Steeves G.M., Gordon R., Choi B.C., Nanorod surface plasmon enhancement of laser-induced ultrafast demagnetization, Sci. Rep., 5, 1, (2015); Acquaroli L.N., Matrix Method for Thin Film Optics, (2018); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, (1935); Abo G.S., Hong Y.-K., Park J., Lee J., Lee W., Choi B.-C., Definition of magnetic exchange length, IEEE Trans. Magn., 49, 8, pp. 4937-4939, (2013)","B.C. Choi; Department of Physics and Astronomy, University of Victoria, Victoria, V8P 5C2, Canada; email: bchoi@uvic.ca","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85099748574" +"Neeraj K.; Pancaldi M.; Scalera V.; Perna S.; D'Aquino M.; Serpico C.; Bonetti S.","Neeraj, Kumar (57194112313); Pancaldi, Matteo (56020605000); Scalera, Valentino (57193953627); Perna, Salvatore (56439259300); D'Aquino, Massimiliano (9732823500); Serpico, Claudio (23013514800); Bonetti, Stefano (23972463400)","57194112313; 56020605000; 57193953627; 56439259300; 9732823500; 23013514800; 23972463400","Magnetization switching in the inertial regime","2022","Physical Review B","105","5","054415","","","","29","10.1103/PhysRevB.105.054415","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125181724&doi=10.1103%2fPhysRevB.105.054415&partnerID=40&md5=2adfb61ceb8d86dee48cccf4562d7354","Department of Physics, Stockholm University, Stockholm, 106 91, Sweden; Faculty of Computer Science, Free University of Bozen-Bolzano, Bolzano, 39100, Italy; DIETI, University of Naples Federico II, Naples, 80125, Italy; Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Mestre, Venezia, 30172, Italy","Neeraj K., Department of Physics, Stockholm University, Stockholm, 106 91, Sweden; Pancaldi M., Department of Physics, Stockholm University, Stockholm, 106 91, Sweden; Scalera V., Faculty of Computer Science, Free University of Bozen-Bolzano, Bolzano, 39100, Italy; Perna S., DIETI, University of Naples Federico II, Naples, 80125, Italy; D'Aquino M., DIETI, University of Naples Federico II, Naples, 80125, Italy; Serpico C., DIETI, University of Naples Federico II, Naples, 80125, Italy; Bonetti S., Department of Physics, Stockholm University, Stockholm, 106 91, Sweden, Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Mestre, Venezia, 30172, Italy","We have numerically solved the Landau-Lifshitz-Gilbert (LLG) equation in its standard and inertial forms to study the magnetization switching dynamics in a 3d thin film ferromagnet. The dynamics is triggered by ultrashort magnetic field pulses of varying width and amplitude in the picosecond and Tesla range. We have compared the solutions of the two equations in terms of switching characteristic, speed, and energy analysis. Both equations return qualitatively similar switching dynamics, characterized by regions of slower precessional behavior and faster ballistic motion. In the case of inertial dynamics, ballistic switching is found in a 25% wider region in the parameter space given by the magnetic field amplitude and width. The energy analysis of the dynamics is qualitatively different for the standard and inertial LLG equations. In the latter case, an extra energy channel, interpreted as the kinetic energy of the system, is available. Such an extra channel is responsible for a resonant energy absorption at THz frequencies, consistent with the occurrence of spin nutation. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the ""https://creativecommons.org/licenses/by/4.0/""Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by ""https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html""Bibsam.","","Ballistics; Energy management; Kinetic energy; Magnetic fields; Magnetization; Momentum; Switching; Energy analysis; Inertial regimes; Its standards; Landau-Lifshitz-Gilbert equations; Magnetic-field pulse; Magnetization switching; Picoseconds; Switching dynamics; Thin-films; Two equation; Kinetics","","","","","Horizon 2020 Framework Programme, H2020, (715452); European Research Council, ERC","K.N., M.P., and S.B. acknowledge support from the European Research Council, Starting Grant No. 715452 MAGNETIC-SPEED-LIMIT.","Mallinson J., IEEE Trans. Magn, 36, (2000); Bertotti G., Mayergoyz I., Serpico C., Dimian M., J. Appl. Phys, 93, (2003); Stohr J., Siegmann H. C., Solid-State Sciences, 5, (2006); Gilbert T. L., IEEE Trans. Magn, 40, (2004); Gerrits T., Van Den Berg H., Hohlfeld J., Bar L., Rasing T., Nature (London), 418, (2002); Kaka S., Russek S. E., Appl. Phys. Lett, 80, (2002); Hiebert W. K., Ballentine G. E., Freeman M. R., Phys. Rev. B, 65, (2002); Tudosa I., Stamm C., Kashuba A., King F., Siegmann H., Stohr J., Ju G., Lu B., Weller D., Nature (London), 428, (2004); Kimel A., Ivanov B., Pisarev R., Usachev P., Kirilyuk A., Rasing T., Nat. Phys, 5, (2009); Serpico C., d'Aquino M., Bertotti G., Mayergoyz I. D., J. Appl. Phys, 95, (2004); Ciornei M.-C., Rubi J. M., Wegrowe J.-E., Phys. Rev. B, 83, (2011); Wegrowe J.-E., Ciornei M.-C., Am. J. Phys, 80, (2012); Wegrowe J.-E., Olive E., J. Phys.: Condens. Matter, 28, (2016); Bottcher D., Ernst A., Henk J., J. Phys.: Condens. 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Rev. X, 10, (2020); Jhuria K., Hohlfeld J., Pattabi A., Martin E., Cordova A. Y. A., Shi X., Conte R. L., Petit-Watelot S., Rojas-Sanchez J. C., Malinowski G., Nat. Electron, 3, (2020); Thonig D., Eriksson O., Pereiro M., Sci. Rep, 7, (2017); Giordano S., Dejardin P.-M., Phys. Rev. B, 102, (2020); Cherkasskii M., Farle M., Semisalova A., Phys. Rev. B, 102, (2020); Mondal R., Grossenbach S., Rozsa L., Nowak U., Phys. Rev. B, 103, (2021); Mondal R., J. Phys.: Condens. Matter, 33, (2021); Titov S. V., Coffey W. T., Kalmykov Y. P., Zarifakis M., Titov A. S., Phys. Rev. B, 103, (2021); Thibaudeau P., Nicolis S., Eur. Phys. J. B, 94, (2021); Lomonosov A. M., Temnov V. V., Wegrowe J.-E., Phys. Rev. B, 104, (2021); Ruggeri M.; Cherkasskii M., Farle M., Semisalova A., Phys. Rev. B, 103, (2021); Rahman R., Bandyopadhyay S., J. Phys.: Condens. Matter, 33, (2021); Titov S. V., Coffey W. T., Kalmykov Y. P., Zarifakis M., Phys. Rev. B, 103, (2021); Anders J., Sait C., Horsley S., New J. Phys, (2022); Lou P. C., Katailiha A., Bhardwaj R. G., Beyermann W. P., Juraschek D. M., Kumar S., Nano Lett, 21, (2021); Gupta R., Husain S., Kumar A., Brucas R., Rydberg A., Svedlindh P., Adv. Opt. Mater, 9, (2021); Alvarez L. F., Pla O., Chubykalo O., Phys. Rev. B, 61, (2000); Laroze D., Bragard J., Suarez O. J., Pleiner H., IEEE Trans. Magn, 47, (2011)","S. Bonetti; Department of Physics, Stockholm University, Stockholm, 106 91, Sweden; email: stefano.bonetti@fysik.su.se","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85125181724" +"Martin-Rio S.; Frontera C.; Pomar A.; Balcells L.; Martinez B.","Martin-Rio, Sergi (57211396336); Frontera, Carlos (7004493280); Pomar, Alberto (56273876800); Balcells, Lluis (7003784544); Martinez, Benjamin (7101643972)","57211396336; 7004493280; 56273876800; 7003784544; 7101643972","Suppression of spin rectification effects in spin pumping experiments","2022","Scientific Reports","12","1","224","","","","6","10.1038/s41598-021-04319-z","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85122492634&doi=10.1038%2fs41598-021-04319-z&partnerID=40&md5=fe0cc4ee8c43c8dd98f75a14b3137a1d","Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain","Martin-Rio S., Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain; Frontera C., Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain; Pomar A., Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain; Balcells L., Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain; Martinez B., Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Campus UAB, Bellaterra, 08193, Spain","Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements. We show an experimental study in the well-known Py/Pt system by using a coplanar waveguide (CPW). Results obtained demonstrate that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line. A progressive reduction of this width evidences that SRE contribution to the measured transverse voltage signal becomes negligibly small for sample width below 200 μm. A numerical solution of the Maxwell equations in the CPW-sample setup, by using the Landau-Lifshitz equation with the Gilbert damping term (LLG) as the constitutive equation of the media, and with the proper set of boundary conditions, confirms the obtained experimental results. © 2022, The Author(s).","","article; experimental study","","","","","Severo Ochoa Program, (CEX2019-000917-S, RTI2018-099960-B-I00); Horizon 2020 Framework Programme, H2020; H2020 Marie Skłodowska-Curie Actions, MSCA, (645658); Ministerio de Ciencia, Innovación y Universidades, MCIU; Ministerio de Ciencia e Innovación, MICINN; Horizon 2020; European Regional Development Fund, ERDF","We acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through Severo Ochoa Program (CEX2019-000917-S), RTI2018-099960-B-I00 and funding from the European Union Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 645658 (DAFNEOX Project) and FEDER Program. CF thanks Prof. M. Kostylev for fruitful communications.","Hirohata A., Yamada K., Nakatani Y., Prejbeanu I.-L., Dieny B., Pirro P., Hillebrands B., Review on spintronics: Principles and device applications, J. Mag. Mag. Mat., 509, (2020); Silsbee R.H., Janossy A., Monod P., Coupling between ferromagnetic and conduction-spin-resonance modes at a ferromagnetic—normal-metal interface, Phys. Rev. B, 19, (1979); Tserkovnyak Y., Brataas A., Bauer G.E.W., Halperin B.I., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Rev. Mod. Phys., 77, (2005); Ando K., Takahashi S., Ieda J., Kurebayashi H., Trypiniotis T., Barnes C.H.W., Maekawa S., Saitoh E., Electrically tunable spin injector free from the impedance mismatch problem, Nat. Mater., 10, (2011); Tserkovnyak Y., Brataas A., Bauer G.E.W., Spin pumping and magnetization dynamics in metallic multilayers, Phys. Rev. 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Lett., 105, (2014); van der Riet E., Roozeboom F., Ferromagnetic resonance and eddy currents in high permeable thin films, J. Appl. Physics, 81, (1997); Lin Z., Kostylev M., A rigorous two-dimensional model for the stripline ferromagnetic resonance response of metallic ferromagnetic films, J. Appl. Phys., 117, (2015); Hay R., Kostylev M., Theoretical study of the stripline ferromagnetic resonance response of metallic ferromagnetic films based on an analytical model, SPIN, 6, (2016)","B. Martinez; Instituto de Ciencia de Materiales de Barcelona, ICMAB-CSIC, Bellaterra, Campus UAB, 08193, Spain; email: ben.martinez@icmab.es","","Nature Research","","","","","","20452322","","","34997112","English","Sci. Rep.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85122492634" +"Imamura H.; Arai H.; Matsumoto R.; Yamaji T.; Tsukahara H.","Imamura, Hiroshi (57386086300); Arai, Hiroko (55352879400); Matsumoto, Rie (9634618900); Yamaji, Toshiki (7102897773); Tsukahara, Hiroshi (9271738200)","57386086300; 55352879400; 9634618900; 7102897773; 9271738200","Precession dynamics of a small magnet with non-Markovian damping: Theoretical proposal for an experiment to determine the correlation time","2022","Journal of Magnetism and Magnetic Materials","553","","169209","","","","2","10.1016/j.jmmm.2022.169209","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85126857389&doi=10.1016%2fj.jmmm.2022.169209&partnerID=40&md5=63003285622b1f7837577557f22fddf5","National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan","Imamura H., National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan; Arai H., National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan; Matsumoto R., National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan; Yamaji T., National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan; Tsukahara H., National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Tsukuba, 305-8568, Japan","Recent advances in experimental techniques have made it possible to manipulate and measure the magnetization dynamics on the femtosecond time scale which is the same order as the correlation time of the bath degrees of freedom. In the equations of motion of magnetization, the correlation of the bath is represented by the non-Markovian damping. For development of the science and technologies based on the ultrafast magnetization dynamics it is important to understand how the magnetization dynamics depend on the correlation time. It is also important to determine the correlation time experimentally. Here we study the precession dynamics of a small magnet with the non-Markovian damping. Extending the theoretical analysis of Miyazaki and Seki (1998) we obtain analytical expressions of the precession angular velocity and the effective damping constant for any values of the correlation time under assumption of small Gilbert damping constant. We also propose a possible experiment for determination of the correlation time. © 2022 Elsevier B.V.","Correlation time; Generalized Langevin equation; LLG equation; Non-Markovian damping; Ultrafast spin dynamics","Damping; Degrees of freedom (mechanics); Equations of motion; Magnetization; Magnets; Correlation time; Experimental techniques; Femtosecond time scale; Generalized Langevin equation; LLG equation; Magnetization dynamics; Non-Markovian; Non-markovian damping; Ultra-fast; Ultrafast spin dynamic; Spin dynamics","","","","","Japan Society for the Promotion of Science, KAKEN, (19H01108, JP18H03787); Japan Society for the Promotion of Science, KAKEN","This work is partly supported by JSPS KAKENHI Grant Numbers JP19H01108 and JP18H03787 . ","Landau L., Lifshits E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. 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Phys., 33, 5, pp. 1338-1341, (1960); Mori H., Transport, collective motion, and Brownian motion, Progr. Theoret. Phys., 33, 3, pp. 423-455, (1965); Miyazaki K., Seki K., Brownian motion of spins revisited, J. Chem. Phys., 108, 17, pp. 7052-7059, (1998); Atxitia U., Chubykalo-Fesenko O., Chantrell R.W., Nowak U., Rebei A., Ultrafast spin dynamics: The effect of colored noise, Phys. Rev. Lett., 102, 5, (2009); Gardiner C.W., Stochastic Methods: A Handbook for the Natural and Social Sciences, Springer Series in Synergetics, 13, (2009); Uhlenbeck G.E., Ornstein L.S., On the theory of the Brownian motion, Phys. Rev., 36, 5, pp. 823-841, (1930); Suhl H., Theory of the magnetic damping constant, IEEE Trans. Magn., 34, 4, pp. 1834-1838, (1998); Suhl H., Relaxation Processes in Micromagnetics, (2007); Weijers H.W., Trociewitz U.P., Markiewicz W.D., Jiang J., Myers D., Hellstrom E.E., Xu A., Jaroszynski J., Noyes P., Viouchkov Y., Larbalestier D.C., High field magnets with HTS conductors, IEEE Trans. Appl. Supercond., 20, 3, pp. 576-582, (2010)","H. Imamura; National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan; email: h-imamura@aist.go.jp","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85126857389" +"Nikolić B.K.","Nikolić, Branislav K. (7006055333)","7006055333","Annihilation of topological solitons in magnetism with spin-wave burst finale and electronic spin pumping over ultrabroadband frequency range","2022","International Conference on Metamaterials, Photonic Crystals and Plasmonics","","","","403","","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85179878211&partnerID=40&md5=80411181e9b85388eb52fa0c42cedd73","Department of Physics & Astronomy, University of Delaware, Newark, 19716, DE, United States","Nikolić B.K., Department of Physics & Astronomy, University of Delaware, Newark, 19716, DE, United States","This talk introduces recently developed [1-5] multiscale quantum-classical hybrid formalism, where time-dependent nonequilibrium Green functions (TDNEGF) describe quantum-mechanically conduction electrons while they interact with dynamical noncollinear magnetic textures of localized magnetic moments (LMMs) described by the classical Landau-Lifshitz-Gilbert (LLG) equation. © 2023, META Conference. All rights reserved.","","","","","","","","","Petrovic M. D., Popescu B. S., Bajpai U., Plechac P., Nikolic B. K., Phys. Rev. Applied, 10, (2018); Bajpai U., Nikolic B. K., Phys. Rev. B, 99, (2019); Petrovic M. D., Bajpai U., Plechac P., Nikolic B. K., Phys. Rev. B, 104, (2021); Bajpai U., Nikolic B. K., Phys. Rev. Lett, 125, (2020); Suresh A., Petrovic M. D., Bajpai U., Yang H., Nikolic B. K., Phys. Rev. Applied, 15, (2021); Woo S., Delaney T., Beach G. S. D., Nat. Phys, 13, (2017); Zhang S., Zhang S. S.-L., Phys. Rev. Lett, 102, (2009)","B.K. Nikolić; Department of Physics & Astronomy, University of Delaware, Newark, 19716, United States; email: bnikolic@udel.edu","Zouhdi S.","META Conference","","12th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2022","19 July 2022 through 22 July 2022","Torremolinos","300599","24291390","","","","English","Int. Conf. Mater. Photon. Cryst. Plasmon.","Conference paper","Final","","Scopus","2-s2.0-85179878211" +"Huang L.; Meng J.; Zhu D.; Yuan Y.","Huang, Liyang (56818163000); Meng, Jin (35201482900); Zhu, Danni (56069641400); Yuan, Yuzhang (56161158600)","56818163000; 35201482900; 56069641400; 56161158600","Minimum Spatial Filling Rate of the Ferrite Required to Excite the Microwave Oscillations in the Gyromagnetic NLTL","2022","IEEE Transactions on Plasma Science","50","1","","23","28","5","1","10.1109/TPS.2021.3135022","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85122060902&doi=10.1109%2fTPS.2021.3135022&partnerID=40&md5=89e67f211bc8a259765fe03cb5b1c025","National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China","Huang L., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Meng J., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Zhu D., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; Yuan Y., National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China","The gyromagnetic nonlinear transmission line (NLTL) is a promising compact, solid-state, and frequency-agile high-power microwave (HPM) source. This article discusses the minimum spatial filling rate of the ferrite required to excite the microwave oscillations in the gyromagnetic NLTL based on simultaneously solving Maxwell's equation and Landau-Lifshitz-Gilbert (LLG) equation in the 2-D cylindrical coordinate system. The results reveal that the different filling rate of the ferrite affects the output waveforms. When the filling rate of the ferrite is lower than 50%, the gyromagnetic NLTL is not able to excite significant oscillations. With the increase of the filling rate, the oscillations become more and more violent. Moreover, the influences of the inner radius of the outer conductor and the dielectric materials are also studied in this article. It is found that with the inner radius of the outer conductor increasing, the oscillations are reduced. The dielectric materials have no significant effects on the performance of the gyromagnetic NLTL when the gyromagnetic NLTL is long enough. This kind of characteristic is important for engineering design. © 1973-2012 IEEE.","Ferrite; gyromagnetic nonlinear transmission line (NLTL); high-power microwave (HPM); Landau-Lifshitz-Gilbert (LLG) equation","Dielectric materials; Electric lines; Filling; Magnetic anisotropy; Maxwell equations; Microwave devices; Microwaves; Nonlinear equations; Saturation magnetization; Filling rate; Gyromagnetic nonlinear transmission line; Gyromagnetism; High-power microwave; Landau-lifshitz-gilbert equation.; Landau-Lifshitz-Gilbert equations; Magneto-mechanical effects; Microwave oscillation; Nonlinear transmission lines; Perpendicular magnetic anisotropy; Ferrite","","","","","National Natural Science Foundation of China, NSFC, (62101580); China Postdoctoral Science Foundation, (2020M683730); Natural Science Foundation of Hubei Province, (2021CFB260)","This work was supported in part by the National Natural Science Foundation of China under Grant 62101580, in part by the China Postdoctoral Science Foundation under Grant 2020M683730, and in part by the Natural Science Foundation of Hubei Province under Grant 2021CFB260.","Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, J. Appl. Phys., 117, 21, (2015); Yamasaki F.S., Rossi J.O., Barroso J.J., Schamiloglu E., Operation of a gyromagnetic line at low and high voltages with simultaneous axial and azimuthal biases, IEEE Trans. Plasma Sci., 46, 7, pp. 2573-2581, (2018); Huang L., Meng J., Zhu D., Yuan Y., Field-line coupling method for the simulation of gyromagnetic nonlinear transmission line based on the Maxwell-LLG system, IEEE Trans. Plasma Sci., 48, 11, pp. 3847-3853, (2020); Tie W., Et al., Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application, Plasma Sci. Technol., 21, 9, (2019); Rostov V.V., Bykov N.M., Bykov D.N., Klimov A.I., Koval'chuk O.B., Romanchenko I.V., Generation of subgigawatt RF pulses in nonlinear transmission lines, IEEE Trans. Plasma Sci., 38, 10, pp. 2681-2685, (2010); Bragg J.B., Dickens J.C., Neuber A.A., Ferrimagnetic nonlinear transmission lines as high-power microwave sources, IEEE Trans. Plasma Sci., 41, 1, pp. 232-237, (2013); Fairbanks A.J., Darr A.M., Garner A.L., A review of nonlinear transmission line system design, IEEE Access, 8, pp. 148606-148621, (2020); Dolan J.E., Simulation of shock waves in the ferrite-load coaxial transmission line with axial bias, J. Phys. D: Appl. Phys., 32, 5, pp. 237-242, (1999); Yao Z., Tok R.U., Itoh T., Wang Y.E., A multiscale unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics, IEEE Trans. Microw. Theory Techn., 66, 6, pp. 2683-2696, (2018); Landau L.D., Bell J.S., Kearsley M.J., Pitaevskii L.P., Electro-Dynamics of Continuous Media, 8, (2013); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Aziz M.M., McKeever C., Wide-band electromagnetic wave propagation and resonance in long cobalt nanoprisms, Phys. Rev. A, Gen. Phys., 13, 3, (2020); Rado G.T., Weertman J.R., Spin-wave resonance in a ferromagnetic metal, J. Phys. Chem. Solids, 11, pp. 315-333, (1959); Reale D.V., Coaxial Ferromagnetic Based Gyromagnetic Transmission Line As Compact High Power Microwave Sources, (2013); Ulmaskulov M.R., Et al., Four-channel generator of 8-GHz radiation based on gyromagnetic non-linear transmitting lines, Rev. Sci. Instrum., 90, 6, (2019); COMSOL Multiphysics User's Guide, COMSOL, (2005); Bragg J.-W.B., Sullivan W.W., Mauch D., Neuber A.A., Dickens J.C., All solid-state high power microwave source with high repetition frequency, Rev. Sci. Instrum., 84, 5, (2013); Simmons C., Bragg J.-W.-B., Dickens J., Neuber A., Frequency agility of a ferrite-loaded, nonlinear transmission line, Proc. IEEE Int. Power Modulator High Voltage Conf. (IPMHVC), pp. 749-751, (2012); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Y., Gyromagnetic RF source for interdisciplinary research, Rev. Sci. Instrum., 88, 2, (2017); Rangel E.G.L., Rossi J.O., Barroso J.J., Yamasaki F.S., Schamiloglu E., Practical constraints on nonlinear transmission lines for RF generation, IEEE Trans. Plasma Sci., 47, 1, pp. 1000-1016, (2019); Solarski R.C., Et al., High voltage solid dielectric coaxial ferrimagnetic nonlinear transmission line, Proc. 19th IEEE Pulsed Power Conf. (PPC), San Francisco, CA, USA, pp. 1-3, (2013)","J. Meng; National Key Laboratory of Science and Technology on Vessel Integrated Power System, Naval University of Engineering, Wuhan, 430000, China; email: mengjinemc@163.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00933813","","ITPSB","","English","IEEE Trans Plasma Sci","Article","Final","","Scopus","2-s2.0-85122060902" +"Kawai T.; Takeda S.; Ohtake M.","Kawai, Tetsuroh (37107742500); Takeda, Shigeru (8222172300); Ohtake, Mitsuru (59066582800)","37107742500; 8222172300; 59066582800","Development of effective permeability to complex permeability and its application taking account of demagnetization factor","2021","IEEJ Transactions on Fundamentals and Materials","141","5","","311","316","5","0","10.1541/ieejfms.141.311","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85105284311&doi=10.1541%2fieejfms.141.311&partnerID=40&md5=7bed1b96b14433827978d2ea3080693e","Faculty of Engineering, Yokohma National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan; Magnontech Ltd., 785-16 Juroken, Kumagaya, 360-0846, Japan","Kawai T., Faculty of Engineering, Yokohma National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan; Takeda S., Magnontech Ltd., 785-16 Juroken, Kumagaya, 360-0846, Japan; Ohtake M., Faculty of Engineering, Yokohma National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan","Effective permeability taking account of demagnetization factor is widely used in the field of the magnetic engineering. A development of this effective permeability to complex permeability in the high frequency domain is studied. In comparison with the solution of LLG equation, it shows that the permeability in the low frequency domain and the resonance frequency calculated by using demagnetization factor are almost corresponding to those calculated by LLG equation. However, the good agreement is not seen in the resonance absorption peak width. Furthermore, the measured complex permeability of a Ni-Fe film is compared with the calculations by using demagnetization factor. © 2021 The Institute of Electrical Engineers of Japan.","Complex permeability; Demagnetization factor; Effective permeability; Ferromagnetic resonance; LLG equation; Radio frequency","Binary alloys; Frequency domain analysis; Iron alloys; Complex permeability; Demagnetization factors; Effective permeability; High frequency domain; ITS applications; Low frequency domain; Resonance absorption; Resonance frequencies; Demagnetization","","","","","","","Watson J. K., Applications on magnetism, (1985); Ohta K., Jiki-kogaku no kiso II, (1973); Perrin G., Peuzin J. G., Acher O., Control of the resonance frequency of soft ferromagnetic amorphous thin film by strip patterning, J. Appl. Phys, 81, 8, pp. 5166-5168, (1997); Takeda S., Motomura S., Hotchi T., Suzuki H., Permeability measurement system up to 10 GHz using all shielded shorted microstrip line, J. Jpn. Soc. Powder Powder Metall, 61, S1, pp. S303-S307, (2014); Zhuang Y., Vroubel M., Rejaei B., Burghartz J. N., Attenborough K., Shape-induced ultrahigh magnetic anisotropy and ferromagnetic resonance frequency of micropatterned thin Permalloy films, J. Appl. Phys, 99, 8, pp. 08C7051-08C7053, (2006); Muroga S., Endo Y., Mitsuzuka Y., Shimada Y., Yamaguchi M., Estimation of Peak Frequency of Loss in Noise Suppressor Using Demagnetizing Factor, IEEE Trans. Magn, 47, 2, pp. 300-303, (2011); Waki H., Igarashi H., Honma T., Estimation of Effective Permeability of Magnetic Composite Materials, IEEE Trans. Magn, 41, 5, pp. 1520-1523, (2011); Lina G. Q., Li Z. W., Chen L., Wu Y. P., Ong C. K., Influence of demagnetizing field on the permeability of soft magnetic composites, J. Magn. Magn. Mater, 305, 2, pp. 291-295, (2006); Chevalier A., Le Floc'h M., Dynamic permeability in soft magnetic composite materials, J. Appl. Phys, 90, 7, pp. 3462-3465, (2001); Takeda S., Suzuki H., Wideband Measurement System of H using All Shielded Shorted Microstrip Line, J. Magn. Soc. Jpn, 33, 3, pp. 171-174, (2009)","T. Kawai; Faculty of Engineering, Yokohma National University, Hodogaya-ku, Yokohama, 79-5 Tokiwadai, 240-8501, Japan; email: kawai-tetsuroh-zn@ynu.ac.jp","","Institute of Electrical Engineers of Japan","","","","","","03854205","","","","Japanese","IEEJ Trans. Fundam. Mater.","Article","Final","","Scopus","2-s2.0-85105284311" +"Ponsudana M.; Amuda R.; Madhumathi R.; Brinda A.; Kanimozhi N.","Ponsudana, M. (57224221584); Amuda, R. (57204372018); Madhumathi, R. (57220995052); Brinda, A. (23977702800); Kanimozhi, N. (57224215432)","57224221584; 57204372018; 57220995052; 23977702800; 57224215432","Confinement of stable skyrmionium and skyrmion state in ultrathin nanoring","2021","Physica B: Condensed Matter","618","","413144","","","","7","10.1016/j.physb.2021.413144","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85107262357&doi=10.1016%2fj.physb.2021.413144&partnerID=40&md5=b8dafb5319ed98cbd9244c446d4dc661","Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India","Ponsudana M., Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India; Amuda R., Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India; Madhumathi R., Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India; Brinda A., Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India; Kanimozhi N., Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, Tamil Nadu, India","Magnetic skyrmionium is a donut-shaped spin texture with zero topological number (Q) and has promising application in future spintronic devices. In this work, using micromagnetic simulation based on Landau-Lifshitz-Gilbert (LLG) equation, we report the generation of skyrmionium in an ultrathin magnetic nanoring in the presence of Dzyaloshinskii-Moriya interaction (DMI) and external magnetic field. By varying the DMI strength and outer diameter of a nanoring, the possibilities of creation of other skyrmion states (kπ states) are explored and we have reported the existence of 3π state and 4π state in nanoring for the first time. Also, we report that the transition of skyrmion state from kπ to (k-1)π occurs for a few millitesla (mT) magnetic fields in the out-of-plane configuration. Further, we have demonstrated the degeneration of skyrmionium (Q=0) into an isolated skyrmion (Q=±1) and a pair of skyrmions (Q=−2) in a nanoring of small dimension by applying an in-plane spin-polarized current. A complete study of the generation of skyrmionium and its topological stability is done by performing the micromagnetic simulation. Our results will provide guidelines for the design of spin-polarized current-controlled skyrmionium-skyrmion based spintronic memory and logic devices. © 2021","Micromagnetic simulation; Nanoring; Skyrmion; Skyrmionium","Magnetic fields; Magnetic logic devices; Nanorings; Nanostructured materials; Textures; Topology; Dzyaloshinskii-Moriya interaction; Micromagnetic simulations; Nanoring; Skyrmionia; Skyrmions; Spin textures; Spin-polarized currents; Spintronics device; Topological number; Ultra-thin; Spin polarization","","","","","DST-SERB; Department of Science and Technology, Ministry of Science and Technology, India, डीएसटी; Science and Engineering Research Board, SERB, (EMR/2016/003032); Ministry of Science and Technology, Taiwan, MOST","Funding text 1: This work of MP, RA and AB was supported by DST-SERB Grant No: EMR/2016/003032. The authors sincerely thank DST, Ministry of Science and Technology, Government of India.; Funding text 2: This work of MP, RA and AB was supported by DST - SERB Grant No: EMR/2016/003032 . The authors sincerely thank DST , Ministry of Science and Technology , Government of India . ","Bogdanov A., Hubert A., The stability of vortex-like structures in uniaxial ferromagnets, J. Magn. Magn Mater., 195, 1, pp. 182-192, (1999); Everschor-Sitte K., Masell J., Reeve R.M., Klaui M., Perspective: magnetic skyrmions—overview of recent progress in an active research field, J. Appl. Phys., 124, 24, (2018); Nagaosa N., Tokura Y., Topological properties and dynamics of magnetic skyrmions, Nat. Nanotechnol., 8, 12, pp. 899-911, (2013); Finocchio G., Buttner F., Tomasello R., Carpentieri M., Klaui M., Magnetic skyrmions: from fundamental to applications, J. Phys. D Appl. Phys., 49, 42, (2016); Zhang X., Et al., Skyrmion-electronics: writing, deleting, reading and processing magnetic skyrmions toward spintronic applications, J. Phys. Condens. Matter, 32, 14, (2020); Back C., Et al., The 2020 skyrmionics roadmap, J. Phys. D Appl. Phys., 53, 36, (2020); Zhang X., Et al., Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory, Sci. Rep., 5, pp. 1-6, (2015); Zhang X., Zhou Y., Ezawa M., Antiferromagnetic skyrmion: stability, creation and manipulation, Sci. Rep., 6, (2016); Kolesnikov A.G., Stebliy M.E., Samardak A.S., V Ognev A., “Skyrmionium–high velocity without the skyrmion Hall effect, Sci. Rep., 8, 1, pp. 1-8, (2018); Finazzi M., Et al., Laser-induced magnetic nanostructures with tunable topological properties, Phys. Rev. Lett., 110, 17, (2013); Zhang X., Et al., Control and manipulation of a magnetic skyrmionium in nanostructures, Phys. Rev. B, 94, 9, (2016); Shen M., Zhang Y., Ou-Yang J., Yang X., You L., Motion of a skyrmionium driven by spin wave, Appl. Phys. Lett., 112, 6, (2018); Leonov A.O., Rossler U.K., Mostovoy M., Target-skyrmions and skyrmion clusters in nanowires of chiral magnets, EPJ Web Conf., 75, (2014); Zhang S., Kronast F., van der Laan G., Hesjedal T., Real-space observation of skyrmionium in a ferromagnet-magnetic topological insulator heterostructure, Nano Lett., 18, 2, pp. 1057-1063, (2018); Guimaraes A.P., “Magnetism of Nanodisks, Nanorings, Nanowires, and Nanotubes,” in Principles Of Nanomagnetism, pp. 201-229, (2017); Beg M., Pepper R.A., Fangohr H., User interfaces for computational science: a domain specific language for OOMMF embedded in Python, AIP Adv., 7, 5, (2017); Beg M., Pepper R.A., Kluyver T., Mulkers J., Leliaert J., Fangohr H., Ubermag/Ubermag: Meta Package for Ubermag Project, (2019); Donahue M.J., Porter D.G., “OOMMF User's Guide Nat. Inst. Stand. Technol., Gaithersburg,” D, Tech. Rep. NISTIR 6376, (1999); Zhang S., Li Z., Roles of nonequilibrium conduction electrons on the magnetization dynamics of ferromagnets, Phys. Rev. Lett., 93, 12, (2004); Talapatra A., Mohanty J., Scalable magnetic skyrmions in nanostructures, Comput. Mater. Sci., 154, pp. 481-487, (2018); Sampaio J., Cros V., Rohart S., Thiaville A., Fert A., Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures, Nat. Nanotechnol., 8, 11, pp. 839-844, (2013); Behera A.K., Mishra S.S., Mallick S., Singh B.B., Bedanta S., “Size and shape of skyrmions for variable Dzyaloshinskii–Moriya interaction and uniaxial anisotropy, J. Phys. D Appl. Phys., 51, 28, (2018); Shi X., Et al., Skyrmions based spin-torque nano-oscillator, IEEE Magn. Lett., 8, pp. 1-5, (2017); Cortes-Ortuno D.I., OOMMFPy, (2019); Rohart S., Thiaville A., Skyrmion confinement in ultrathin film nanostructures in the presence of Dzyaloshinskii-Moriya interaction, Phys. Rev. B, 88, 18, (2013); Hagemeister J., Siemens A., Rozsa L., Vedmedenko E.Y., Wiesendanger R., “Controlled creation and stability of k π skyrmions on a discrete lattice, Phys. Rev. B, 97, 17, (2018); Zhang X., Zhou Y., Ezawa M., Magnetic bilayer-skyrmions without skyrmion Hall effect, Nat. Commun., 7, 1, pp. 1-7, (2016); Kang W., Huang Y., Zhang X., Zhou Y., Zhao W., Skyrmion-electronics: an overview and outlook, Proc. IEEE, 104, 10, pp. 2040-2061, (2016); Du H., Et al., Interaction of individual skyrmions in a nanostructured cubic chiral magnet, Phys. Rev. Lett., 120, 19, (2018); Wang J., Jin C., Song C., Xia H., Wang J., Liu Q., Rapid creation and reversal of skyrmion in spin-valve nanopillars, J. Magn. Magn Mater., 474, pp. 472-476, (2019); Bo L., Et al., Formation of skyrmion and skyrmionium in confined nanodisk with perpendicular magnetic anisotropy, J. Phys. D Appl. Phys., 53, 19, (2020)","R. Amuda; Centre for Nonlinear Dynamics, Department of Physics, PSG College of Technology, Coimbatore, 641 004, India; email: amuacademics@gmail.com","","Elsevier B.V.","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-85107262357" +"Moumni M.; Tilioua M.","Moumni, Mohammed (57195377066); Tilioua, Mouhcine (6507877823)","57195377066; 6507877823","A finite element approximation of a current-induced magnetization dynamics model","2022","Journal of Mathematical Modeling","10","1","","53","69","16","4","10.22124/JMM.2021.19486.1673","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85123435535&doi=10.22124%2fJMM.2021.19486.1673&partnerID=40&md5=64cbb5dfbc5507b7e95767556399ca40","MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismail University of Meknes, P.O. Box: 509 Boutalamine, Errachidia, 52000, Morocco","Moumni M., MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismail University of Meknes, P.O. Box: 509 Boutalamine, Errachidia, 52000, Morocco; Tilioua M., MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismail University of Meknes, P.O. Box: 509 Boutalamine, Errachidia, 52000, Morocco","Micromagnetics is a continuum theory describing magnetization patterns inside ferromagnetic media. The dynamics of a ferromagnetic material are governed by the Landau-Lifshitz equation. This equation is highly nonlinear and has a non-convex constraint. In this work, a finite element approximation of a current-induced magnetization dynamics model is proposed. The model consists of a modified Landau-Lifshitz-Gilbert (LLG) equation incorporating spin transfer torque. The scheme pre-serves a non-convex constraint, requires only a linear solver at each time step and is easily applicable to the limiting cases. As the time and space steps tend to zero, a proof of convergence of the numerical solution to a (weak) solution of the modified LLG equation is given. Numerical results are presented to show the effect of the injected current on magnetization switching. © 2022.","Ferromagnetism; Finite elements; Magnetization dynamics; Spin polarized current","","","","","","","","Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl Sci, 6, pp. 299-316, (2006); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and non uniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Banas L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell– Landau–Lifshitz–Gilbert equation, SIAM J. Numer. Anal, 46, pp. 1399-1422, (2008); Banas L., Page M., Praetorius D., A convergent linear finite element scheme for the Maxwell– Landau–Lifshitz–Gilbert equation, (2012); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal, 43, pp. 220-238, (2005); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, (1996); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in a bounded domain, Differ. Integral Equ, 14, pp. 213-229, (2001); Carbou G., Labbe S., Trelat E., Control of travelling walls in a ferromagnetic nanowire, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 51-59, (2008); Hamid M., Usman M., Haq R.Ul., Tian Z., A spectral approach to analyze the nonlinear oscillatory fractional-order differential equations, Chaos Solitons and Fractals, 146, (2021); Hamid M., Usman M., Haq R.U., Tian Z., Wang W., Linearized stable spectral method to analyze two-dimensional nonlinear evolutionary and reaction-diffusion models, Numer. Methods Partial Differ. Equations, pp. 1-19, (2020); Hamid M., Usman M., Tian Z., Wang W., A stable computational approach to analyze semi-relativistic behavior of fractional evolutionary problems, Numer. Methods Partial Differ. Equations, pp. 1-15, (2008); Hamid M., Usman M., Tian Z., Wang W., Hybrid fully spectral linearized scheme for time-fractional evolutionary equations, Math. Methods Appl. Sci, 44, pp. 3890-3912, (2021); Hamid M., Usman M., Zubair T., Haq R.l., Shafee A., An efficient analysis for N-soliton, Lump and lump–kink solutions of time-fractional (2+ 1)-Kadomtsev–Petviashvili equation, Physica A Stat. Mech. Appl, 528, (2019); Jeong D., Kim J., An accurate and robust numerical method for micromagnetics simulations, Curr. Appl. Phys, 14, pp. 476-483, (2014); Johnson C., Numerical Solution of Partial Differential Equations by the Finite Element Method, (1987); Khodadadian A., Hosseini K., Manzour-ol-Ajdad A., Hedayati M., Kalantarinejad R., Heitzinger C., Optimal design of nanowire field-effect troponin sensors, Comput. Biol. Med. Comput. Biol. Med, 87, pp. 46-56, (2017); Khodadadian A., Parvizi M., Heitzinger C., An adaptive multilevel Monte Carlo algorithm for the stochastic drift-diffusion-Poisson system, Comput. Methods Appl. Mech. Engrg, 368, (2020); Khodadadian A., Taghizadeh L., Heitzinger C., Three-dimensional optimal multi-level Monte– Carlo approximation of the stochastic drift–diffusion–Poisson system in nanoscale devices, J. Com-put. Electron, 17, pp. 76-89, (2018); Kohno H., Tatara G., Shibata J., Suzuki Y., Microscopic Calculation of Spin Torques and Forces, J. Magn. Magn. Mater, 310, pp. 2020-2022, (2006); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromag-netism, SIAM Rev, 48, pp. 439-483, (2006); Labbe S., Fast computation for large magnetostatic systems adapted for micromagnetism, SIAM J. Sci. Comput, 26, pp. 2160-2175, (2005); Le K.-N., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz-Gilbert equations, Comput. Math. 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Phys, 357, pp. 125-141, (2018); Shen K., Tatara G., Wu M.W., Existence of vertical spin stiffness in Landau-Lifshitz-Gilbert equation in ferromagnetic semiconductors, Phys. Rev. B, 83, (2011); Slonczewski J.C., Current-driven excitation of magnetic multilayer, J. Magn. Magn. Mater, 159, pp. L1-L7, (1996); Tilioua M., Comportement asymptotique de materiaux ferromagntiques minces avec energie de surface et/ou couplage dechange inter-couches, (2003); Tilioua M., Current-induced magnetization dynamics. Global existence of weak solutions, J. Math. Anal. Appl, 373, pp. 635-642, (2011); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Japan J. Appl. Math, 2, pp. 69-84, (1985); Weinan E., Han J., Jentzen A., Deep learning-based numerical methods for high-dimensional parabolic partial differential equations and backward stochastic differential equations, Commun. Math. Stat, 5, pp. 349-380, (2017)","M. Moumni; MAIS Laboratory, MAMCS Group, FST Errachidia, Moulay Ismail University of Meknes, Errachidia, P.O. Box: 509 Boutalamine, 52000, Morocco; email: md.moumni@gmail.com","","University of Guilan","","","","","","2345394X","","","","English","J. Math. Model.","Article","Final","","Scopus","2-s2.0-85123435535" +"Rahman R.; Bandyopadhyay S.","Rahman, Rahnuma (57225958196); Bandyopadhyay, Supriyo (57203099871)","57225958196; 57203099871","An observable effect of spin inertia in slow magneto-dynamics: Increase of the switching error rates in nanoscale ferromagnets","2021","Journal of Physics Condensed Matter","33","35","355801","","","","12","10.1088/1361-648X/ac0cb4","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85111142503&doi=10.1088%2f1361-648X%2fac0cb4&partnerID=40&md5=0247e3161834a45ed61e2fe8f8cd3f66","Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States","Rahman R., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Bandyopadhyay S., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States","The Landau-Lifshitz-Gilbert (LLG) equation, used to model magneto-dynamics in ferromagnets, tacitly assumes that the angular momentum associated with spin precession can relax instantaneously when the real or effective magnetic field causing the precession is turned off. This neglect of 'spin inertia' is unphysical and would violate energy conservation. Recently, the LLG equation was modified to account for inertia effects. The consensus, however, seems to be that such effects would be unimportant in slow magneto-dynamics that take place over time scales much longer that the relaxation time of the angular momentum, which is typically few fs to perhaps ∼100 ps in ferromagnets. Here, we show that there is at least one very serious and observable effect of spin inertia even in slow magneto-dynamics. It involves the switching error probability associated with flipping the magnetization of a nanoscale ferromagnet with an external agent, such as a magnetic field. The switching may take ∼ns to complete when the field strength is close to the threshold value for switching, which is much longer than the angular momentum relaxation time, and yet the effect of spin inertia is felt in the switching error probability. This is because the ultimate fate of a switching trajectory, i.e. whether it results in success or failure, is influenced by what happens in the first few ps of the switching action when nutational dynamics due to spin inertia hold sway. Spin inertia increases the error probability, which makes the switching more error-prone. This has vital technological significance because it relates to the reliability of magnetic logic and memory. © 2021 IOP Publishing Ltd.","magnetic logic and memory; magneto-dynamics; spin inertia; switching failures in nanomagnets","Angular momentum; Errors; Ferromagnetic materials; Ferromagnetism; Magnetic fields; Magnets; Nanomagnetics; Probability; Relaxation time; Switching frequency; Error probabilities; Inertia effects; Landau-Lifshitz-Gilbert equations; Momentum relaxation; Nanoscale ferromagnets; Spin precession; Switching errors; Technological significance; Spin fluctuations","","","","","","","Sayad M, Rausch R, Potthoff M, Inertia effects in the real time dynamics of a quantum spin coupled to a Fermi sea, Europhys. Lett, 116, (2016); Mondal R, Berritta M, Nandy A K, Oppeneer P M, Relativistic theory of magnetic inertia in ultrafast spin dynamics, Phys. Rev. B, 96, (2017); Mondal R, Berritta M, Oppeneer P M, Generalization of Gilbert damping and magnetic inertia parameter as a series of higher-order relativistic terms, J. Phys.: Condens. Matter, 30, (2018); Bajpai U, Nikolic B K, Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions, Phys. Rev. B, 99, (2019); Bhattacharjee S, Nordstrom L, Fransson J, Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett, 108, (2012); Thonig D, Eriksson O, Pereiro M, Magnetic moment of inertia within the torque-torque correlation model, Sci. Rep, 7, (2017); Gilbert T L, A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, pp. 3443-3449, (2004); Ciornei M-C, Rubi J M, Wegrowe J-E, Magnetization dynamics in the intertial regime: nutation predicted at short time scales, Phys. Rev. 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Phys, 17, pp. 245-250, (2020); Giordano S, Dejardin P-M, Derivation of magnetic inertial effects from the classical mechanics of a circular current loop, Phys. Rev. B, 102, (2020); 2021 Chaos theory; Hawkins B, Sensitivity to initial conditions in chaos Wolfram Demonstration Projects, (2011); Hollar D W, Chaos theory and sensitive dependence on initial conditions Trajectory Analysis in Health Care ed D W Hollar, pp. 117-130, (2017); Bandyopadhyay S, Nanomagnetic Boolean logic: the tempered (and realistic) vision, IEEE Access, 9, pp. 7743-7750, (2021); Winters D, Abeed M A, Sahoo S, Barman A, Bandyopadhyay S, Reliability of magnetoelastic switching of nonideal nanomagnets with defects: a case study for the viability of straintronic logic and memory, Phys. Rev. Appl, 12, (2019); Fashami M S, Munira K, Bandyopadhyay S, Ghosh A W, Atulasimha J, Switching of dipole coupled multiferroic nanomagnets in the presence of thermal noise: reliability of nanomagnetic logic, IEEE Trans. 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Bandyopadhyay; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, United States; email: sbandy@vcu.edu","","IOP Publishing Ltd","","","","","","09538984","","JCOME","34144548","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85111142503" +"Mustaghfiroh Q.; Kurniawan C.; Djuhana D.","Mustaghfiroh, Qoimatul (57212169560); Kurniawan, Candra (55600299500); Djuhana, Dede (26027849100)","57212169560; 55600299500; 26027849100","Magnetization Dynamic Analysis of Square Model CoFe and CoFeB Ferromagnetic Materials Using Micromagnetic Simulation","2019","IOP Conference Series: Materials Science and Engineering","553","1","012009","","","","3","10.1088/1757-899X/553/1/012009","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85076108349&doi=10.1088%2f1757-899X%2f553%2f1%2f012009&partnerID=40&md5=67c9c3db2bc129b356ead66ae2fa857c","Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, KampusBaru UI, Depok, 16424, Indonesia; Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Tangerang Selatan, 15314, Indonesia","Mustaghfiroh Q., Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, KampusBaru UI, Depok, 16424, Indonesia; Kurniawan C., Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, KampusBaru UI, Depok, 16424, Indonesia, Research Center for Physics, Indonesian Institute of Sciences (LIPI), Puspiptek Office Area Tangerang Selatan, 15314, Indonesia; Djuhana D., Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, KampusBaru UI, Depok, 16424, Indonesia","In this study, dynamic magnetization of square model CoFe and CoFeB ferromagnetic materials were observed using micromagnetic simulation based on LLG equation. The geometrical side size was varied from 50 to 500 nm with the thickness of 5 nm and 10 nm. For simulation process, the used damping factor was 0.05 and the cell size of 2.5×2.5×2.5 nm3 was used with respect to exchange length of CoFe and CoFeB. The external magnetic fields were applied in in-plane and out-plane direction to generate magnetic hysteresis loop. It is found that the coercivity decreased as square size increased for both in-plane and out-plane magnetization direction. The coercivity were around 40 to 200 mT for in-plane field magnetization of CoFe. The coercivity tends to constant at 40 mT in diameter less than 100 nm and zero coercivity for diameter greater than 100 nm for out-plane field magnetization. Compared to CoFe, the coercivity in out-plane field is higher than in-plane field in CoFeB square. It is also observed that the switching time and nucleation field increased as the size increased in out-plane direction of both CoFe and CoFeB. The results showed that the different characteristics of magnetic anisotropy of both materials are important in the development of high density magnetic storage. © Published under licence by IOP Publishing Ltd.","Cofe; Cofeb; Hysteresis; Magnetic anisotropy; Micromagnetic","Binary alloys; Cobalt compounds; Coercive force; Ferromagnetic materials; Ferromagnetism; Hysteresis; Magnetic anisotropy; Magnetic logic devices; Magnetic storage; Magnetization; Cofe; Cofeb; External magnetic field; High density magnetic storage; Magnetization direction; Magnetization dynamics; Micromagnetic simulations; Micromagnetics; Boron compounds","","","","","Indexed International Publication","This work is supported by Indexed International Publication Grant (Publikasi Internasional Terindeks, PIT 9) year 2019 No. NKB-0023/UN2.R3.1/HKP.05.00/2019 through DRPM Universitas Indonesia.","Gubin S.P., Koksharov Y.A., Khomutov G.B., Yurkov G.Y., Magnetic nanoparticles: Preparation, structure and properties, Russian Chemical Reviews, 74, (2005); Sundar R.S., Deevi S.C., Soft magnetic FeCo alloys: Alloy development, processing, and properties, International Materials Reviews, 50, pp. 157-192, (2005); Piao H.-G., Choi H.-C., Shim J.-H., Kim D.-H., You C.-Y., Ratchet effect of the domain wall by asymmetric magnetostatic potentials, Applied Physics Letters, 99, (2011); Munakata M., Aoqui S.-I., Yagi M., B-Concentration Dependence on Anisotropy Field of CoFeB Thin Film for Gigahertz Frequency Use, IEEE Transactions on Magnetics, 41, (2005); Ngo D.-T., Quach D.-T., Tran Q.-H., Mohave K., Phan T.-L., Kim D.-H., Perpendicular magnetic anisotropy and the magnetization process in CoFeB/Pd multilayer films, Journal of Physics D: Applied Physics, 47, 44, (2014); Gerhardt T., Micromagnetic Simulations of Ferromagnetic Domain Walls in Nanowires, (2014); Meo A., Chureemart P., Wang S., Chepulskyy R., Thermally Nucleated Magnetic Reversal in CoFeB/MgO Nanodots, (2017); Wang Y., Wei D., Gao K.-Z., Cao J., Fulin W., The role of inhomogeneity of perpendicular anisotropy in magnetic properties of ultra thin CoFeB film, American Institute of Physics, 115, (2014); Horikoshi S., Serpone N., Microwaves in Nanoparticle Synthesis: Fundamentals and Applications, (2013); Mukherjee P.K., Nanomaterials with Immense Potential, Journal of Applicable Chemistry, 5, pp. 714-718, (2016); Donahue M.J., Porter D.G., OOMMF User's Guide, 1.0, (1999); Chaves-O'Flynn G.D., Wolf G., Pinna D., Kent Andrew D., Micromagnetic study of spin transfer switching with a spin polarization tilted out of the free layer plane, Journal of Applied Physics, 117, (2015); Tekgul A., Alper M., Kockar H., Haciismailoglu M., The effect of ferromagnetic and non-ferromagnetic layer thicknesses on the electrodeposited CoFe/Cu multilayers, Journal of Materials Science Materials in Electronics, 26, pp. 2411-2417, (2015); Sinha J., Et al., Influence of boron diffusion on the perpendicular magnetic anisotropy in Ta|CoFeB|MgO ultrathin films, American Institute of Physics, 117, (2015); Guimaraes A.P., Principles of Nanomagnetism., (2009); Liu Y., Hao L., Cao J., Effect of annealing conditions on the perpendicular magnetic anisotropy of Ta/CoFeB/MgO multilayers, AIP Publishing, 6, (2016); Quach D.-T., Et al., Minor hysteresis patterns with a rounded/sharpened reversing behavior in ferromagnetic multilayer, Scientific Report, 8, (2018)","D. Djuhana; Departement of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, Depok, KampusBaru UI, 16424, Indonesia; email: dede.djuhana@sci.ui.ac.id","Kartini E.","Institute of Physics Publishing","","19th International Union of Materials Research Societies - International Conference in Asia, IUMRS-ICA 2018","30 October 2018 through 2 November 2018","Bali","155185","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85076108349" +"Fu S.; Chang R.; Volvach I.; Kuteifan M.; Menarini M.; Lomakin V.","Fu, Sidi (56440692900); Chang, Ruinan (37261104600); Volvach, Iana (55193500500); Kuteifan, Majd (56606258200); Menarini, Marco (56441481800); Lomakin, Vitaliy (35570326300)","56440692900; 37261104600; 55193500500; 56606258200; 56441481800; 35570326300","Block Inverse Preconditioner for Implicit Time Integration in Finite Element Micromagnetic Solvers","2019","IEEE Transactions on Magnetics","55","12","8902292","","","","3","10.1109/TMAG.2019.2910496","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85077495163&doi=10.1109%2fTMAG.2019.2910496&partnerID=40&md5=8fe97394793d8c105aeecabd5c8c23e7","Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States; Center for Memory and Recording Research, San Diego, 92093, CA, United States","Fu S., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Chang R., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Volvach I., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Kuteifan M., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Menarini M., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States; Lomakin V., Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, CA, United States, Center for Memory and Recording Research, San Diego, 92093, CA, United States","A block-inverse preconditioner (BIP) is proposed to accelerate solving implicit time integration in the context of Newton-Krylov approach used in micromagnetic simulations for solving the Landau-Lifshitz-Gilbert equation. A coefficient matrix is generated and stored for the linear system of Newton method. BIP is formulated by subdividing the coefficient matrix into small blocks and directly inverting them. The cost of preconditioning is low since inverting and multiplying small blocks is fast, which can be further minimized by parallel computing on multicore CPUs or GPUs. The effectiveness, speed, robustness, and scalability of BIP is demonstrated by numerical simulation experiments. Comparisons to incomplete LU preconditioning methods are conducted to demonstrate the effectiveness of BIP. © 1965-2012 IEEE.","Block inverse; finite element method (FEM); Landau-Lifshitz-Gilbert (LLG) equation; micromagnetics; preconditioner","Finite element method; Linear systems; Matrix algebra; Newton-Raphson method; Program processors; Block inverse; Implicit time integration; Incomplete lu preconditioning; Landau-Lifshitz-Gilbert equations; Micromagnetic simulations; Micromagnetics; Numerical simulation experiment; Preconditioners; Inverse problems","","","","","National Science Foundation, NSF, (1610315); National Science Foundation, NSF","This work was supported by the National Science Foundation under Award 1610315.","Escobar M.A., Lubarda M.V., Li S., Chang R., Livshitz B., Lomakin V., Advanced micromagnetic analysis of write head dynamics using Fastmag, IEEE Trans. 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New York, (1973); Pommerell C., Solution of large unsymmetric systems of linear equations, Ph.D. Dissertation, (1992); Saad Y., ILUT: A dual threshold incomplete LU factorization, Numer. Linear Algebra Appl., 1, 4, pp. 387-402, (1994); Saad Y., Iterative Methods for Sparse Linear Systems, (2003); Fu S., Et al., Micromagnetics on high-performance workstation and mobile computational platforms, J. Appl. Phys., 117, 17, (2015); Wang E., Et al., Intel math kernel library, High-Performance Computing on the Intel Xeon Phi. Cham, pp. 167-188, (2014); Li S., Chang R., Boag A., Lomakin V., Fast electromagnetic integral-equation solvers on graphics processing units, IEEE Antennas Propag. Mag., 54, 5, pp. 71-87, (2012)","V. Lomakin; Department of Electrical and Computer Engineering, University of California at San Diego, San Diego, 92093, United States; email: vlomakin@eng.ucsd.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85077495163" +"Li P.; Chen J.; Du R.; Wang X.-P.","Li, Panchi (57211560785); Chen, Jingrun (57219146828); Du, Rui (56763448500); Wang, Xiao-Ping (56382555600)","57211560785; 57219146828; 56763448500; 56382555600","Numerical Methods for Antiferromagnets","2020","IEEE Transactions on Magnetics","56","4","8984262","","","","5","10.1109/TMAG.2020.2971939","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85082388700&doi=10.1109%2fTMAG.2020.2971939&partnerID=40&md5=5a2376ef7e7c8172461d1c5025465156","School of Mathematical Sciences, Soochow University, Suzhou, China; Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, China; Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, Hong Kong","Li P., School of Mathematical Sciences, Soochow University, Suzhou, China; Chen J., School of Mathematical Sciences, Soochow University, Suzhou, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, China; Du R., School of Mathematical Sciences, Soochow University, Suzhou, China, Mathematical Center for Interdisciplinary Research, Soochow University, Suzhou, China; Wang X.-P., Department of Mathematics, Hong Kong University of Science and Technology, Hong Kong, Hong Kong","Compared with ferromagnetic counterparts, antiferromagnetic materials are considered as the future of spintronic applications since these materials are robust against the magnetic perturbation, produce no stray field, and display ultrafast dynamics. There are (at least) two sets of magnetic moments in antiferromagnets (AFMs) (with magnetization of the same magnitude but antiparallel directions) and ferrimagnets (with the magnetization of the different magnitude). The coupled dynamics of the bipartite collinear AFMs is modeled by a coupled system of Landau-Lifshitz-Gilbert equations with additional terms originated from the interlattice exchange, which leads to femtosecond magnetization dynamics in AFMs. In this article, we develop three Gauss-Seidel projection methods for micromagnetics simulation in AFMs and ferrimagnets. They are first-order accurate in time and second-order accurate in space, and only solve linear systems of equations with constant coefficients at each step. Femtosecond dynamics, Néel wall structure, and phase transition in the presence of an external magnetic field for AFMs are provided with the femtosecond stepsize. © 1965-2012 IEEE.","Antiferromagnet (AFM); antiferromagnetic exchange; Guass-Seidel projection methods (GSPMs); Landau-Lifshitz-Gilbert (LLG) equation; micromagnetics simulation","Antiferromagnetism; Dynamics; Ferrimagnetism; Linear systems; Magnetic moments; Magnetization; Numerical methods; Antiferromagnetic exchange; External magnetic field; Landau-Lifshitz-Gilbert equations; Linear systems of equations; Magnetization dynamics; Micromagnetics simulations; Projection method; Spintronic applications; Antiferromagnetic materials","","","","","General Research Fund, (16302715, 16303318, 16324416); Hong Kong Research Grants Council; Macau Special Administrative Region, (101/2016/A3, 11501399); NSFC-University Grants Committee; RGC, (N-HKUST620/15); National Natural Science Foundation of China, NSFC, (11971021); National Natural Science Foundation of China, NSFC; Science and Technology Development Fund, STDF; National Basic Research Program of China (973 Program), (2018YFB0204404); National Basic Research Program of China (973 Program)","ACKNOWLEDGMENT The work of Jingrun Chen was supported in part by the National Key Research and Development Program of China under Grant 2018YFB0204404, in part by NSFC under Grant 11971021, and in part by the Science and Technology Development Fund, Macau Special Administrative Region (SAR) under Grant 101/2016/A3. The work of Rui Du was supported by NSFC under Grant 11501399. The work of Xiao-Ping Wang was supported in part by the Hong Kong Research Grants Council through the General Research Fund (GRF) under Grant 16302715, Grant 16324416, and Grant 16303318 and in part by NSFC-University Grants Committee (RGC) Joint Research under Grant N-HKUST620/15.","Zutic I., Fabian J., Das Sarma S., Spintronics: Fundamentals and applications, Rev. Mod. Phys, 76, 2, pp. 323-410, (2004); Gomonay E.V., Loktev V.M., Spintronics of antiferromagnetic systems Review Article, Low Temp. Phys, 40, 1, pp. 17-35, (2014); Sinova J., Jungwirth T., Gomonay O., Antiferromagnetic spintronics, Rev. Mod. Phys, 11, 4; Puliafito V., Et al., Micromagnetic modeling of terahertz oscillations in an antiferromagneic material driven by the spin Hall effect, Phys. Rev. B, Condens. Matter, 99, 2, (2019); Ivanov B.A., Spin dynamics of antiferromagnets under action of femtosecond laser pulses (Review Article), Low Temp. Phys, 40, 2, pp. 91-105, (2014); Sanches-Tejerina L., Puliafito V., Amori P.K., Carpentieri M., Finocchio G., Dynamics of Domain Walls Motion Driven by Spinorbit Torque in Antiferromagnets, (2019); Gomonay O., Klaui M., Sinova J., Manipulating antiferromagnets with magnetic fields: Ratchet motion of multiple domain walls induced by asymmetric field pulses, Appl. Phys. Lett, 109, 14; Gomonay O., Jungwirth T., Sinova J., High antiferromagnetic domain wall velocity induced by Néel spin-orbit torque, Phys. Rev. Lett, 117, 1, (2016); Shiino T., Et al., Antiferromagnetic domain wall motion drvien by spinorbit torque, Phys. Rev. Lett, 117, 8, (2016); Wadley P., Et al., Electrical switching of an antiferromagnet, Science, 351, pp. 587-590, (2016); Fiebig M., Et al., Ultrafast magnetization dynamics of antiferromagnetic compounds, J. Phys. D, Appl. Phys, 41, 16, (2008); Lisenkov I., Khymyn R., Akerman J., Sun N.X., Ivanov B.A., Subterahertz ferrimagnetic spin-Transfer torque oscillator, Phys. Rev. B, Condens. Matter, 100, 10, (2019); Kim K.-J., Et al., Fast domain wall motion in the vicinity of the angular momentum compensation temperature of ferrimagnets, Nature Mater, 16, 12, pp. 1187-1192; Kim S.K., Tserkovnyak Y., Fast vortex oscillations in a ferrimagnetic disk near the angular momentum compensation point, Appl. Phys. Lett, 111, 3; Ivanov B.A., Ultrafast spin dynamics and spintronics for ferrimagnets close to the spin compensation point (Review), Low Temp. Phys, 45, 9, pp. 935-963; Zaspel C.E., Galkina E.G., Ivanov B.A., High-frequency currentcontrolled vortex oscillations in ferrimagnetic disks, Phys. Rev. A, Gen. Phys, 12, (2019); Landau L., Lifshitz E., On the theory of the dispersion of magetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T., A Lagrangian formulation of the gyromagnetic equation of the magnetization field, Phys. Rev, 100, pp. 1243-1255, (1955); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, 3, pp. 439-483, (2006); Garcia-Cervera C.J., Numerical micromagnetics: A review, Boletin Sociedad Espanola Matematica Aplicada, 39, pp. 103-135, (2007); Cimrak I., A Survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng, 15, 3, pp. 1-37, (2007); Francois A., Pascal J., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci, 16, 2, pp. 299-316, (2006); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo G., Azzerboni B., A numerical solution of the magnetization reversal modeling in a permalloy thin film using fifth order Runge-Kutta method with adaptive step size control, Phys. B, Condens. Matter, 403, pp. 1163-1194, (2008); Yamada H., Hayashi N., Implicit solution of the Landau-Lifshitz-Gilbert equation by the Crank-Nicolson method, J. Magn. Soc. Jpn, 28, 8, pp. 924-931, (2004); Bartels S., Andreas P., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal, 44, 4, pp. 1405-1419, (2006); Fuwa A., Ishiwata T., Tsutsumi M., Finite difference scheme for the Landau-Lifshitz equation, Jpn. J. Indust. Appl. Math, 29, 1, pp. 83-110, (2012); Wang X., Garcia-Cervera C.J., Weinan W.E., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys, 171, 1, pp. 357-372, (2001); Li P., Xie C., Du R., Chen J., Wang X.-P., Two improved Gauss-Seidel projection methods for Landau-Lifshitz-Gilbert equation, J. Comput. Phys, 401; Wang W.E.X., Numerical methods for the Landau-Lisfshitz equation, SIAM J. Numer. Anal, 38, 5, pp. 1647-1665, (2000); Chen J., Wang C., Xie C., Convergence Analysis of A Second-order Semi-implicit Projection Method for Landau-Lifshitz Equation, (2019); Cimrak I., Error estimates for a semi-implicit numerical scheme solving the Landau-Lifshitz equation with an exchange field, IMA J. Numer. Anal, 25, 3, pp. 611-634, (2005); Xie C., Garcia-Cervera C.J., Wang C., Zhou Z., Chen J., Secondorder semi-implicit projection methods for micromagnetics simulations, J. Comput. Phys, 404, (2020); Coey J.M.D., Magnetism and Magnetic Materials (Photocopy Edition), (2014); Jacobs I.S., Spin-flopping in MnF2 by high magnetic fields, J. Appl. Phys, 32, 3, pp. S61-S62, (1961)","J. Chen; School of Mathematical Sciences, Soochow University, Suzhou, China; email: jingrunchen@suda.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85082388700" +"Ogrin F.Y.","Ogrin, Feodor Y. (57193655015)","57193655015","3D FDTD-LLG modelling of magnetisation dynamics in thin film ferromagnetic structures","2022","International Conference on Metamaterials, Photonic Crystals and Plasmonics","","","","404","405","1","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85179874255&partnerID=40&md5=08534963db1bd4642344e19102608e42","School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom","Ogrin F.Y., School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom","Here I present a model which uses 3D finite-difference-time-domain (FDTD) approach together with Landau-Lifshits_Gilbert (LLG) equation to find the exact solutions for magnetisation dynamics in ferromagnetic thin films integrated with metal-dielectric structures. Several case studies are demonstrated, in which the model is validated against analytical and experimental methods. © 2023, META Conference. All rights reserved.","","","","","","","","","Aziz M. M., Progress In Electromagnetics Research B, 15, pp. 1-29, (2009); Gurevich A.G., Melkov G.A., Magnetisation oscillations and waves, V33, (1962)","F.Y. Ogrin; School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom; email: f.y.ogrin@exeter.ac.uk","Zouhdi S.","META Conference","","12th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2022","19 July 2022 through 22 July 2022","Torremolinos","300599","24291390","","","","English","Int. Conf. Mater. Photon. Cryst. Plasmon.","Conference paper","Final","","Scopus","2-s2.0-85179874255" +"Papusoi C.; Le T.; Admana R.; Mani P.; Desai M.","Papusoi, C. (56133379700); Le, T. (55806253200); Admana, R. (57194688373); Mani, P. (57214021933); Desai, M. (7201841155)","56133379700; 55806253200; 57194688373; 57214021933; 7201841155","Evaluation of the exchange coupling between adjacent magnetic layers using time-resolved magneto-optic Kerr effect (TRMOKE)","2021","Journal of Physics D: Applied Physics","54","36","365004","","","","2","10.1088/1361-6463/ac0a08","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85110391906&doi=10.1088%2f1361-6463%2fac0a08&partnerID=40&md5=002b9505a410a69fb27af8e69a72ad36","Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States","Papusoi C., Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States; Le T., Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States; Admana R., Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States; Mani P., Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States; Desai M., Western Digital, 5601 Great Oaks Parkway, San Jose, 95119, CA, United States","Vertical exchange coupling between the adjacent layers of a magnetic multilayer has a strong impact on the magnetization reversal mechanism. Time-resolved magneto-optic Kerr effect (TRMOKE) is used to evaluate the vertical exchange coupling energy per unit film surface JV between two Co1-X PtX layers denominated A (x = 27 at. %) and B (x = 22 at. %), separated by a CoCrRu weakly-magnetic layer denominated exchange control layer (ECL), as a function of the ECL thickness dECL in the range of 0-5 nm. The A and B layers have perpendicular anisotropy and thicknesses dA = 7 nm and dB = 5.6 nm. For this purpose, the dependence of the acoustic magnetization oscillation frequency fAC on dECL is measured using TRMOKE and the dependence fAC (JV) is theoretically assessed using two models: (a) the two-spins model (TSM) assumes a parallel orientation of spins across the thickness of each layer; (b) the chain-of-spins model (CSM) takes into account the possibility of a non-collinear orientation of spins across the thickness of the A and B layers. In the case of dECL ≥ 1 nm corresponding to JV ≤ 1 erg cm-2, TSM and CSM offer similar JV values. Below dECL ≈ 1 nm, CSM provides a more accurate estimate of JV than TSM which underestimates JV the more significantly the lower is dECL. © 2021 IOP Publishing Ltd.","Acoustic and optic oscillation modes; Exchange coupling; Landau-Lifshitz-Gilbert (LLG) equation; Perpendicular magnetic recording (PMR); Time-resolved MOKE (TRMOKE)","Chromium alloys; Cobalt alloys; Exchange coupling; Magnetic materials; Magnetic multilayers; Magnetometers; Optical Kerr effect; Ruthenium alloys; Ternary alloys; Adjacent layers; Exchange coupling energy; Magnetic layers; Magnetization reversal mechanisms; Magneto-optic Kerr effect; Oscillation frequency; Parallel orientation; Perpendicular anisotropy; Magnetization reversal","","","","","","","Richter H J, J. Phys. D: Appl. Phys, 40, (2007); Richter H J, J. Magn. Magn. Mater, 321, (2009); Wang X, Valcu B, Yeh N-H, Appl. Phys. Lett, 94, (2009); Evans R F L, Chantrell R W, Novak U, Lyberatos A, Richter H J, Appl. Phys. Lett, 100, (2012); Weller D, Moser A, IEEE Trans. Magn, 35, (1999); Kryder M, Gage E C, McDaniel T W, Challener W, Rottmayer R E, Ju G, Hsia Y T, Erden M F, Proc. IEEE, 96, (2008); Zhu J G, Zhu X, Tang Y, IEEE Trans. Magn, 44, (2008); Victora R H, Shen X, IEEE Trans. Magn, 41, (2005); Richter H J, Dobin A Y, J. Appl. Phys, 99, (2006); Suess D, Schrefl T, Fahler S, Kirschner M, Hrkac G, Dorfbauer F, Fidler J, Appl. Phys. Lett, 87, (2005); Hagedorn B, J. Appl. Phys, 41, (1970); Suess D, Appl. Phys. Lett, 89, (2006); Choe G, Ikeda Y, IEEE Trans. Magn, 50, (2014); Zhu J-G, Wang Y, IEEE Trans. Magn, 47, (2011); Richter H J, Dobin A Y, J. Magn. Magn. Mat, 287, (2005); Dobin A Y, Richter H J, J. Appl. Phys, 101, (2007); Gao K-Z, Bertram N, IEEE Trans. Magn, 38, (2002); Victora R H, Shen X, IEEE Trans. Magn, 41, (2005); Zhao B, Xue H, Wu G, Zhu Z, Ren Y, Jin Q Y, Zhang Z, Appl. Phys. Lett, 115, (2019); Papusoi C, Le T, Lo C C H, Kaiser C, Desai M, Acharya R, J. Phys. D: Appl. Phys, 51, (2018); Callen H B, Callen E, J. Phys. Chem. Solids, 27, (1966); Burd J, Huq M, Lee E W, J. Magn. Magn. Mater, 5, (1977); Sato H, Shimatsu T, Okazaki Y, Kitakami O, Okamoto S, Aoi H, Muraoka H, Nakamura Y, IEEE Trans. Magn, 43, (2007); Shimatsu T, Sato H, Oikawa T, Inaba Y, Kitakami O, Okamoto S, Aoi H, Muraoka H, Nakamura Y, IEEE Trans. Magn, 40, (2004); Miyasaka Y, Hashida M, Nishii T, Inoue S, Sakabe S, Appl. Phys. Lett, 106, (2015); Li M, Jiang Z H, Zheng W M, Chen L Y, Shen D F, J. Magn. Soc. Japan, 22, (1998); Ordal M A, Long L L, Bell R J, Bell S E, Bell R R, Alexander R W, Ward C A, Appl. Opt, 22, (1983); Eyrich C, Et al., J. Appl. Phys, 111, (2012); Berkov D V, Gorn N L, Handbook of Advanced Magnetic Materials, 2, (2006); Berkov D V, J. Magn. Magn. Mater, 161, (1996); Cochran J F, Heinrich B, Arrott A S, Phys. Rev. B, 34, (1986); Vukadinovic V, Ben Youssef J, Castel V, Phys. Rev. B, 79, (2009); Morrish A H, The Physical Principles of Magnetism, (2001)","C. Papusoi; Western Digital, San Jose, 5601 Great Oaks Parkway, 95119, United States; email: cristian.papusoi@wdc.com","","IOP Publishing Ltd","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","","Scopus","2-s2.0-85110391906" +"Gholipour A.; Babaii M.","Gholipour, Alireza (56414562900); Babaii, Mahla (57221131860)","56414562900; 57221131860","Analyzing the effects of impressed current on the behavior of STT-MTJ devices through shaping the PDF of the magnetization vector","2020","2020 28th Iranian Conference on Electrical Engineering, ICEE 2020","","","9261001","","","","0","10.1109/ICEE50131.2020.9261001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85098328800&doi=10.1109%2fICEE50131.2020.9261001&partnerID=40&md5=8cbe3dc45a8190102303a0bb217d2ed0","School of Electrical Engineering, Shahid Beheshti University, Tehran, Iran","Gholipour A., School of Electrical Engineering, Shahid Beheshti University, Tehran, Iran; Babaii M., School of Electrical Engineering, Shahid Beheshti University, Tehran, Iran","The states of the magneto resistive tunnel junction (MTJ) devices are determined by the direction of their magnetization vector. The Landau-Lifshitz-Gilbert (LLG) differential equation governs the trajectory of the magnetization vector. For the low current values or the switching pulses that have small durations, the end tip of this vector points randomly to somewhere in the 4π [Steradian] of the spherical coordinate. To find the probability density function (PDF) of this distribution, the Fokker-Planck stochastic differential equation (SDE) should be solved. In this paper the PDF of the spin-transfer torque (STT) MTJ s are analyzed. It is shown that by properly shaping the current, one can shape the PDF of the magnetization vector. Hence, the state of the device can be switched completely or can be kept in an uncertain situation with the same probability of switching or non-switching to occur. Biasing the device in such a way that its state become unclear will have applications in designing pseudo number generators or cryptography circuits. © 2020 IEEE.","Fokker-Planck equation; MTJ; PDF; SLLG; Switching probability","Fokker Planck equation; Magnetic devices; Magnetization; Number theory; Probability distributions; Stochastic systems; Tunnel junctions; Vectors; Impressed current; Landau-Lifshitz-Gilbert; Magnetization vector; Number generator; Probability density function (pdf); Spherical coordinates; Spin transfer torque; Stochastic differential equations; Probability density function","","","","","","","Goncalves O., Prenat G., Dieny B., Radiation hardened mram-based FPGA, Ieee Transactions on Magnetics (TMAG), 49, 7, pp. 4355-4358, (2013); Zhao W., Belhaire E., Chappert C., Mazoyer P., Spin transfer torque (stt)-mram based run time reconfiguration FPGA circuit, Acm Transactions on Embedded Computing Systems, 9, 2, (2009); Kwon K., Choday S.H., Kim Y., Roy K., She-nvff: Spin hall effect-based nonvolatile flip-flop for power gating architecture, Ieee Electron Device Letters, 35, 4, pp. 488-490, (2014); Wang M., Peng S., Zhang Y., Zhang Y., Zhang Y., Zhang Q., Ravelosona D., Zhao W., A multilevel cell for stt-mram realized by capping layer adjustment, Ieee Transactions on Magnetics, 51, 11, pp. 1-4, (2015); Suzuki D., Hanyu T., Magnetic-tunnel-junction based low-energy nonvolatile flip-flop using an area-efficient self-terminated write driver, Journal of Applied Physics, 117, 17, (2015); Wolf S.A., Awschalom D.D., Buhrman R.A., Daughton J.M., Von Molnar S., Roukes M.L., Chtchelkanova A.Y., Treger D.M., Spintronics: A spin-based electronics vision for the future, Science, 294, 5546, pp. 1488-1495, (2001); Suzuki D., Natsui M., Endoh T., Ohno H., Hanyu T., Six-input lookup table circuit with 62% fewer transistors using nonvolatile logicin-memory architecture with series/parallel-connected magnetic tunnel junctions, J. Appl. Phys., 111, 7, (2012); Fukushima A., Seki T., Yakushiji K., Kubota H., Imamura H., Yuasa S., Ando K., Spin dice: A scalable truly random number generator based on spintronics, Applied Physics Express 7, 8, (2014); Gholipour A., Rajaei R., The behavior analysis of magnetoresistive tunnel junction devices in state space, Ieee Transactions on Nanotechnology, 18, pp. 798-805, (2019); Gholipour A., Rajaei R., Magnetization vector control and resistance analysis of stt p-mtj devices, Electrical Engineering (ICEE), Iranian Conference on, pp. 250-254, (2018); D'Aquino M., Serpico C., Coppola G., Mayergoyz I.D., Bertotti G., Midpoint numerical technique for stochastic Landau-Lifshitz-Gilbert dynamics, Journal of Applied Physics, 99, 8, (2006); Chen B.J., Cai K., Han G.C., Lim S.T., Tran M., A portable dynamic switching model for perpendicular magnetic tunnel junctions considering both thermal and process variations, Ieee Transactions on Magnetics, 51, 11, pp. 1-4, (2015); Wang Y., Cai H., De Barros Naviner L.A., Zhang Y., Zhao X., Deng E., Klein J., Zhao W., Compact model of dielectric breakdown in spin-transfer torque magnetic tunnel junction, Ieee Transactions on Electron Devices, 63, 4, pp. 1762-1767, (2016); Butler W.H., Mewes T., Mewes C.K.A., Visscher P.B., Rippard W.H., Russek S.E., Heindl R., Switching distributions for perpendicular spin-torque devices within the macrospin approximation, Ieee Transactions on Magnetics, 48, 12, pp. 4684-4700, (2012); Mert T.M., Upadhyaya P., Bhave S.A., Camsari K.Y., Modular compact modeling of mtj devices, Ieee Transactions on Electron Devices, 65, 10, pp. 4628-4634, (2018); Wang Z., Et al., Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque, Journal of Physics D: Applied Physics, 48, 6, (2015); Sarkka S., Solin A., Applied Stochastic Differential Equations, 10, (2019); Xie Y., Behin-Aein B., Ghosh A.W., Fokker- Planck study of parameter dependence on write error slope in spin-torque switching, Ieee Transactions on Electron Devices, 64, 1, pp. 319-324, (2016)","","","Institute of Electrical and Electronics Engineers Inc.","","28th Iranian Conference on Electrical Engineering, ICEE 2020","4 August 2020 through 6 August 2020","Tabriz","165457","","978-172817296-5","","","English","Iranian Conf. Electr. Eng., ICEE","Conference paper","Final","","Scopus","2-s2.0-85098328800" +"Schaffer S.; Mauser N.J.; Schrefl T.; Suess D.; Exl L.","Schaffer, Sebastian (57219785077); Mauser, Norbert J. (7004158395); Schrefl, Thomas (7005780657); Suess, Dieter (7004076065); Exl, Lukas (53863546300)","57219785077; 7004158395; 7005780657; 7004076065; 53863546300","Machine Learning Methods for the Prediction of Micromagnetic Magnetization Dynamics","2022","IEEE Transactions on Magnetics","58","2","","","","","4","10.1109/TMAG.2021.3095251","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85110911147&doi=10.1109%2fTMAG.2021.3095251&partnerID=40&md5=b12c3e9eb1a3545975dec610304f5508","University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria; Wolfgang Pauli Institute C/o Faculty of Mathematics, University of Vienna, Vienna, 1010, Austria; Christian Doppler Laboratory for Magnet Design Through Physics Informed Machine Learning, Department of Integrated Sensor Systems, Danube University Krems, Krems an der Donau, 3500, Austria; Faculty of Physics, University of Vienna, Vienna, 1010, Austria","Schaffer S., University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria, Wolfgang Pauli Institute C/o Faculty of Mathematics, University of Vienna, Vienna, 1010, Austria; Mauser N.J., University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria, Wolfgang Pauli Institute C/o Faculty of Mathematics, University of Vienna, Vienna, 1010, Austria; Schrefl T., University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria, Christian Doppler Laboratory for Magnet Design Through Physics Informed Machine Learning, Department of Integrated Sensor Systems, Danube University Krems, Krems an der Donau, 3500, Austria; Suess D., University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria, Faculty of Physics, University of Vienna, Vienna, 1010, Austria; Exl L., University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria, Wolfgang Pauli Institute C/o Faculty of Mathematics, University of Vienna, Vienna, 1010, Austria","Machine learning (ML) entered the field of computational micromagnetics only recently. The main objective of these new approaches is the automatization of solutions of parameter-dependent problems in micromagnetism, such as fast response curve estimation modeled by the Landau-Lifschitz-Gilbert (LLG) equation. Data-driven models for the solution of time- and parameter-dependent partial differential equations require high-dimensional training data structures. ML, in this case, is by no means a straightforward trivial task; it needs algorithmic and mathematical innovation. Our work introduces theoretical and computational conceptions of the certain kernel and neural network (NN)-based dimensionality reduction approaches for efficient prediction of solutions via the notion of low-dimensional feature space integration. We introduce efficient treatment of kernel ridge regression and kernel principal component analysis via low-rank approximation. The second line follows NN autoencoders as a nonlinear data-dependent dimensional reduction for the training data with a focus on accurate latent space variable description suitable for a feature space integration scheme. We verify and compare numerically by means of a NIST standard problem. The low-rank kernel method approach is fast and surprisingly accurate, while the NN scheme can even exceed this level of accuracy at the expense of significantly higher costs. © 1965-2012 IEEE.","Computational micromagnetism; deep neural networks (NNs); kernel methods; low-rank approximation; nonlinear model order and dimensionality reduction; regularized autoencoders (AEs)","Approximation theory; Dimensionality reduction; Neural networks; Predictive analytics; Regression analysis; Dimensional reduction; Efficient predictions; Kernel principal component analyses (KPCA); Kernel ridge regressions; Low rank approximations; Machine learning methods; Magnetization dynamics; Parameter dependents; Learning systems","","","","","","","Fischbacher J., Et al., Micromagnetics of rare-earth efficient permanent magnets, J. Phys. D, Appl. Phys., 51, 19, (2018); Suess D., Et al., Topologically protected vortex structures for low-noise magnetic sensors with high linear range, Nature Electron., 1, 6, (2018); Miltat J.E., Donahue M.J., Numerical micromagnetics: Finite difference methods, Handbook of Magnetism and Advanced Magnetic Materials, (2007); Schrefl T., Hrkac G., Bance S., Suess D., Ertl O., Fidler J., Numerical Methods in Micromagnetics (Finite Element Method), (2007); Abert C., Exl L., Selke G., Drews A., Schrefl T., Numerical methods for the stray-field calculation: A comparison of recently developed algorithms, J. Magn. Magn. Mater., 326, pp. 176-185, (2013); Exl L., A magnetostatic energy formula arising from the L2-orthogonal decomposition of the stray field, J. Math. Anal. Appl., 467, 1, pp. 230-237, (2018); Kovacs A., Et al., Learning magnetization dynamics, J. Magn. Magn. Mater., 491, (2019); Exl L., Mauser N.J., Schrefl T., Suess D., Learning timestepping by nonlinear dimensionality reduction to predict magnetization dynamics, Commun. Nonlinear Sci. Numer. Simul., 84, (2020); Exl L., Mauser N.J., Schaffer S., Schrefl T., Suess D., Prediction of Magnetization Dynamics in A Reduced Dimensional Feature Space Setting Utilizing A Low-rank Kernel Method, (2020); Scholkopf B., Smola A., Muller K.-R., Kernel principal component analysis, Proc. Int. Conf. Artif. Neural Netw., pp. 583-588, (1997); McMichael R., μmAG Standard Problem #4 Results, (2021); Kingma D.P., Ba J., Adam: A Method for Stochastic Optimization, (2014); Kim B., Azevedo V.C., Thuerey N., Kim T., Gross M., Solenthaler B., Deep fluids: A generative network for parameterized fluid simulations, Computer Graphics Forum, 38, 2, pp. 59-70, (2019); Chollet F., Et al., Keras, (2015); Lee J.A., Verleysen M., Nonlinear Dimensionality Reduction, (2007); Saitoh S., Theory of reproducing kernels and its applications, Longman Sci. Tech., 22, 1, pp. 139-142, (1988); Weinberger K.Q., Sha F., Saul L.K., Learning a kernel matrix for nonlinear dimensionality reduction, Proc. 21st Int. Conf. Mach. Learn., (2004); Williams C., Seeger M., The effect of the input density distribution on kernel-based classifiers, Proc. 17th Int. Conf. Mach. Learn, pp. 1159-1166, (2000); Wathen A.J., Zhu S., On spectral distribution of kernel matrices related to radial basis functions, Numer. Algorithms, 70, 4, pp. 709-726, (2015); Williams C.K., Seeger M., Using the Nyström method to speed up kernel machines, Proc. Adv. Neural Inf. Process. Syst., pp. 682-688, (2001); Fowlkes C., Belongie S., Chung F., Malik J., Spectral grouping using the Nystrom method, IEEE Trans. Pattern Anal. Mach. Intell., 26, 2, pp. 214-225, (2004); Shalev-Shwartz S., Ben-David S., Understanding Machine Learning: From Theory to Algorithms, (2014); Welling M., Kernel ridge regression, Max Wellings Classnotes in Machine Learning, 2013, pp. 1-3; Bakir G.H., Weston J., Scholkopf B., Learning to find preimages, Proc. Adv. Neural Inf. Process. Syst., 16, 7, pp. 449-456, (2004)","L. Exl; University of Vienna Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, 1010, Austria; email: lukas.exl@univie.ac.at","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85110911147" +"Jordan D.; McCloskey P.; Wei G.","Jordan, D. (57200740717); McCloskey, P. (6603889329); Wei, G. (59071666200)","57200740717; 6603889329; 59071666200","A GPU accelerated micromagnetic simulator for modelling complex magnetic systems","2021","Journal of Magnetism and Magnetic Materials","537","","168204","","","","0","10.1016/j.jmmm.2021.168204","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85108338801&doi=10.1016%2fj.jmmm.2021.168204&partnerID=40&md5=3930c1cde917fde202d3a029eee67d71","Tyndall National Institute, University College Cork, Cork, Ireland","Jordan D., Tyndall National Institute, University College Cork, Cork, Ireland; McCloskey P., Tyndall National Institute, University College Cork, Cork, Ireland; Wei G., Tyndall National Institute, University College Cork, Cork, Ireland","This paper demonstrates an object orientated GPU accelerated micromagnetic simulator designed to model the material characteristics of complex magnetic alloy systems. The GPU simulator is written in C++ and uses object orientated programming to create a class that stores the magnetic information required to solve the Landau-Lifshitz-Gilbert (LLG) equation for a distribution of magnetic objects. Each magnetic object can be assigned individual properties based on the alloy distribution of interest. The simulator is verified against standard problem 4 of the “Micromagnetic Modelling Activity Group” (μmag). Standard problem 4 is chosen as it provides a benchmark for the modelling tools ability to accurately predict the magnetisation dynamics of a 500 nm × 125 nm × 3 nm Permalloy thin film. © 2021","GPU; Magnetic alloys; Micromagnetic simulator; Object orientated","C++ (programming language); Iron alloys; Magnetism; Nickel alloys; Permalloy; Simulators; Alloy system; GPU-accelerated; Landau-Lifshitz-Gilbert equations; Magnetic alloy; Magnetic system; Material characteristics; Micromagnetic simulators; Model complexes; Object orientated; Standard problems; Graphics processing unit","","","","","","","Mathuna C.O., Wang N.N., Kulkarni S., Roy S., Review of integrated magnetics for power supply on chip (PwrSoC), IEEE Trans. Power Electron., 27, pp. 4799-4816, (2012); Masood A., McCloskey P., Mathuna C.O., Kulkarni S., Co-based amorphous thin films on silicon with soft magnetic properties, AIP Adv., 8, (2018); Gardner D.S., Schrom G., Paillet F., Jamieson B., Karnik T., Borkar S., Review of on-chip inductor structures with magnetic films, IEEE Trans. Magn., 45, pp. 4760-4766, (2009); Aimon N., Liao J.X., Ross C.A.; Donahue M., Porter D., OOMMF User's Guide Version 1.0; 1999, Return to citation in text:[1], (1999); Nickolls J., Dally W.J., The GPU computing era, IEEE Micro, 30, pp. 56-69, (2010); Tyson M., (2017); Vansteenkiste A., Van de Wiele B., MuMax: A new high-performance micromagnetic simulation tool, J. Magn. Magn. Mater., 323, pp. 2585-2591, (2011); Li S., Livshitz B., Lomakin V., Graphics processing unit accelerated $ O (N) $ micromagnetic solver, IEEE Trans. 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Jordan; Tyndall National Institute, University College Cork, Cork, Ireland; email: jordande@tcd.ie","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85108338801" +"Petrović M.D.; Mondal P.; Feiguin A.E.; Nikolić B.K.","Petrović, Marko D. (55928482300); Mondal, Priyanka (57208212451); Feiguin, Adrian E. (6602340587); Nikolić, Branislav K. (7006055333)","55928482300; 57208212451; 6602340587; 7006055333","Quantum Spin Torque Driven Transmutation of an Antiferromagnetic Mott Insulator","2021","Physical Review Letters","126","19","197202","","","","10","10.1103/PhysRevLett.126.197202","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85106387874&doi=10.1103%2fPhysRevLett.126.197202&partnerID=40&md5=8239a2784f71b078bbcbfb6ffac1547b","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Department of Physics, Northeastern University, Boston, 02115, MA, United States","Petrović M.D., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Mondal P., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Feiguin A.E., Department of Physics, Northeastern University, Boston, 02115, MA, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","The standard model of spin-transfer torque (STT) in antiferromagnetic spintronics considers the exchange of angular momentum between quantum spins of flowing electrons and noncollinear-to-them localized spins treated as classical vectors. These vectors are assumed to realize Néel order in equilibrium, ↑↓ »↑↓, and their STT-driven dynamics is described by the Landau-Lifshitz-Gilbert (LLG) equation. However, many experimentally employed materials (such as archetypal NiO) are strongly electron-correlated antiferromagnetic Mott insulators (AFMIs) whose localized spins form a ground state quite different from the unentangled Néel state |↑↓ »↑↓ © 2021 American Physical Society. All rights reserved.","","Antiferromagnetic materials; Antiferromagnetism; Ground state; Nickel oxide; Antiferromagnetics; Landau-Lifshitz-Gilbert equations; Localized spin; Noncollinear; Quantum spin; Spin transfer torque; The standard model; article; electron; expectation; torque; Mott insulators","","","","","National Science Foundation, NSF, (1922689, ECCS 1922689); U.S. Department of Energy, USDOE, (DE-SC0019275)","M. D. P., P. M., and B. K. N. were supported by the U.S. National Science Foundation (NSF) Grant No. ECCS 1922689. A. E. F. was supported by the U.S. Department of Energy (DOE) Grant No. DE-SC0019275. ","Baltz V., Manchon A., Tsoi M., Moriyama T., Ono T., Tserkovnyak Y., Antiferromagnetic spintronics, Rev. Mod. Phys, 90, (2018); Jungwirth T., Marti X., Wadley P., Wunderlich J., Antiferromagnetic spintronics, Nat. Nanotechnol, 11, (2016); Zelezny J., Wadley P., Olejnik K., Hoffman A., Ohno H., Spin transport and spin torque in antiferromagnetic devices, Nat. Phys, 14, (2018); Jungfleisch B., Zhang W., Hoffmann A., Perspectives of antiferromagnetic spintronics, Phys. Lett. A, 382, (2018); Manchon A., Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers, Phys. Status Solidi RRL, 11, (2017); Baldrati L., Full angular dependence of the spin Hall and ordinary magnetoresistance in epitaxial antiferromagnetic NiO(001)/Pt thin films, Phys. Rev. B, 98, (2018); Chen X. Z., Antidamping-Torque-Induced Switching in Biaxial Antiferromagnetic Insulators, Phys. Rev. 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B, 81, (2010); Ulbricht T., Schmitteckert P., Is spin-charge separation observable in a transport experiment?, Europhys. Lett, 86, (2009); Schlunzen N., Hermanns S., Scharnke M., Bonitz M., Ultrafast dynamics of strongly correlated fermions-nonequilibrium Green functions and selfenergy approximations, J. Phys. Condens. Matter, 32, (2020); Bertrand C., Parcollet O., Maillard A., Waintal X., Quantum Monte Carlo algorithm for out-of-equilibrium Green's functions at long times, Phys. Rev. B, 100, (2019); Mitrofanov A., Urazhdin S., Nonclassical Spin Transfer Effects in an Antiferromagnet, Phys. Rev. Lett, 126, (2021)","B.K. Nikolić; Department of Physics and Astronomy, University of Delaware, Newark, 19716, United States; email: bnikolic@udel.edu","","American Physical Society","","","","","","00319007","","PRLTA","34047602","English","Phys Rev Lett","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85106387874" +"Akagi F.; Sakamoto Y.; Matsushima N.","Akagi, Fumiko (6604097171); Sakamoto, Yoshito (57480672000); Matsushima, Naofumi (57216177568)","6604097171; 57480672000; 57216177568","Effects of Static Magnetic Fields and Temperature Increase on 3D Magnetic Storage in Heated-Dot Magnetic Recording (Revised May 2021)","2021","Digests of the Intermag Conference","2021-April","","","","","","4","10.1109/INTERMAG42984.2021.9580007","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85125888207&doi=10.1109%2fINTERMAG42984.2021.9580007&partnerID=40&md5=c9182d59f73355ba7bff379fffdbaabc","Department of Applied Physics, School of Advanced Engineering, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan; Graduate School of Electrical Engineering and Electronic, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan","Akagi F., Department of Applied Physics, School of Advanced Engineering, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan, Graduate School of Electrical Engineering and Electronic, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan; Sakamoto Y., Department of Applied Physics, School of Advanced Engineering, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan; Matsushima N., Graduate School of Electrical Engineering and Electronic, Kogakuin University, Shinjuku-ku, Tokyo, 163-8677, Japan","Using the Landau-Lifshitz-Gilbert (LLG) equation, we investigated the effects of static magnetic fields and increase in temperature on 3D magnetic storage in heated-dot magnetic recording (HDMR) in the write process. The recording medium of HDMR was assumed to have double recording layers in which the Curie temperature in the upper layer was lower than that in the lower layer. When the lower layer is recorded, the upper layer must be re-recorded. We then investigated the relationship between the spacing between recording layers and bit error rates. When the thicknesses of upper and lower layers were the same, the minimal spacing for recording nearly without error was 4 nm, thus achieving the critical static magnetic field values for recording different data in each layer. © 2021 IEEE.","3D HDMR; Curie temperature; Heated-dot magnetic recording; LLG; Static magnetic field","Digital storage; Magnetic field effects; Magnetic recording; Magnetic storage; 3d heated-dot magnetic recording; Heated-dot magnetic recording; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Magnetic temperatures; Recording layers; Recording media; Static magnetic fields; Temperature increase; Upper layer; Curie temperature","","","","","Hitachi Corporation","We thank Hitachi Corporation for the use of the simulator. We also thank Dr. Yamakawa from the Akita Industrial Technology Center for calculating the head fields.","Ushiyama J., Akagi F., Ando A., Miyamoto H., 8 tbit/inch2-class bit patterned media for thermally assisted magnetic recording, IEEE Trans. Magn., 49, 7, pp. 3612-3615, (2013); Akagi F., Matsushima N., Effects of dot-position dispersion of BPM, thermal distribution, and head field gradient on bit error rate for HAMR, Jpn. J. Appl. Phys., 59, pp. 1-4, (2019); Liu Z., Gilbert I., Hernandez S., Rea C., Granz S., Zhou H., Blaber M., Huang P.-W., Peng C., Ju G., Dykes J.W., Thiele J.-U., Seigler M.A., Rausch T., Curvature and skew in heat-assisted magnetic recording, IEEE Trans. Magn., 55, 3, (2019); Kief M.T., Victora R.H., Materials for heat-assisted magnetic recording, MRS Bulletin, 43, 2, pp. 87-91, (2018); Hono K., Takahashi Y.K., Ju G., Thiele J.-U., Ajan A., Yang X., Ruiz R., Wan L., Heat-assisted magnetic recording media materials, MRS Bulletin, 43, 2, pp. 93-99, (2018); HAMR Milestone: Seagate Achieves 16TB Capacity on Internal HAMR Test Units, (2018); Miyazaki T., Kitakami O., Okamoto S., Shimada Y., Size effect on the ordering of L10FePt nanoparticles, Phys. Rec., B72, (2005); Albrecht M., Hu G., Moser A., Hellwig O., Terris B.D., Magnetic dot arrays with multiple storage layers, J. Appl. Phys., 97, (2005); Amos N., Butler J., Lee B., Shachar M.H., Hu B., Tian Y., Hong J., Garcia D., Ikkawi R.M., Haddon R.C., Litvinov D., Khizroev S., Multilevel-3D bit patterned magnetic media with 8 signal levels per nanocolumn, PLoS ONE, 7, 7, (2012); Kobayashi T., Nakatani Y., Fujiwara Y., Information stability in three-dimensional heat-assisted magnetic recording, J. Magn. Soc., Jpn., 44, pp. 34-39, (2020); Brown W.F., Thermal fluctuation of a single-domain particle, J. Appl. Phys., 34, pp. 1319-1321, (1963); Akagi F., Igarashi M., Yoshida K., Nakatani Y., Hayashi N., Optimum timing and position of light irradiation for thermally assisted perpendicular recording, Jpn. J. Appl. Phys., 43, 11 A, pp. 7483-7488, (2004); Matsumoto T., Akagi F., Mochizuki M., Miyamoto H., Stipe B., Integrated head design using a nanobeak antenna for thermally assisted magnetic recording, Optics Express, 20, 17, pp. 18946-18954, (2012); Yamakawa K., Ise K., Akagi F., Watanabe K., Igarashi M., Miyamoto H., Write head design for thermally assisted magnetic recording, Dig. ICAUMS2012, 4, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Magnetics Society","2021 IEEE International Magnetic Conference, INTERMAG 2021","26 April 2021 through 30 April 2021","Virtual, Online","177034","00746843","978-073813099-6","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-85125888207" +"Gholipour A.; Rajaei R.","Gholipour, Alireza (56414562900); Rajaei, Ramin (34768978000)","56414562900; 34768978000","Magnetization Vector Control and Resistance Analysis of STT p-MTJ Devices","2018","26th Iranian Conference on Electrical Engineering, ICEE 2018","","","8472470","250","254","4","1","10.1109/ICEE.2018.8472470","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85055658337&doi=10.1109%2fICEE.2018.8472470&partnerID=40&md5=c468c1a03cf78cc6ba8812b1f8316550","Department of Electrical Engineering, Shahid Beheshti University, Tehran, 1983969411, Iran","Gholipour A., Department of Electrical Engineering, Shahid Beheshti University, Tehran, 1983969411, Iran; Rajaei R., Department of Electrical Engineering, Shahid Beheshti University, Tehran, 1983969411, Iran","The resistance of perpendicular MTJ devices (p-MT J)is changed when the magnetization vector of its free ferromagnetic layer is pointed to different angles. However, the MTJ resistance depends not only on the momentary status of the angle of magnetization vector but also on the rate of its change which is determined by the LLG vector differential equation. By maximizing the rate of the changes, faster devices can be obtained. It is shown that an optimum operation point can be found. At this operation point the device switches fast while consumes fair amount of power. The approach is verified using an evaluation circuit and spice simulations. It is shown that MRAM-cell designers can find optimum values ofW/L for the CMOS-transistors to achieve better performance in the whole circuit. © 2018 IEEE.","LLG differential equation; Magnetic random access memory; Magnetic tunnel junction; Numerical methods; State space","Differential equations; Magnetic storage; Magnetization; MRAM devices; Numerical methods; Random access storage; SPICE; State space methods; Tunnel junctions; Vectors; Ferromagnetic layers; Magnetic random access memory; Magnetic tunnel junction; Magnetization vector; Optimum operations; Perpendicular MTJ; Resistance analysis; Vector differential equations; Vector control (Electric machinery)","","","","","","","Kwon K., Choday S.H., Kim Y., Roy K., SHE-NVFF: Spin hall effect-based nonvolatile flip-flop for power gating architecture, IEEE Electron Device Letters, 35, 4, pp. 488-490, (2014); Rajaei R., Fazeli M., Tabandeh M., Soft error-tolerant design of MRAM-based non-volatile latches for sequential logics, IEEE Transactions on Magnetics, 51, 6, pp. 1-14, (2014); Wang M., Peng S., Zhang Y., Zhang Y., Zhang Y., Zhang Q., Ravelosona D., Zhao W., A multilevel cell for STT-MRAM realized by capping layer adjustment, IEEE Transactions on Magnetics, 51, 11, pp. 1-4, (2015); Rajaei R., Mamaghani S.B., A nonvolatile, low-power, and highly reliable MRAM block for advanced microarchitectures, IEEE Transactions on Device and Materials Reliability (TDMR), 17, 2, pp. 472-474, (2017); Suzuki D., Hanyu T., Magnetic-tunnel-junction based low-energy nonvolatile flip-flop using an area-efficient self-terminated write driver, Journal of Applied Physics, 117, 17, (2015); Goncalves O., Prenat G., Dieny B., Radiation hardened MRAMBased FPGA, IEEE Transactions on Magnetics (TMAG), 49, 7, pp. 4355-4358, (2013); Ahari M., Ebrahimi A., Tahoori M.B., Energy efficient partitioning of dynamic reconfigurable MRAM-FPGAS, Proceedings of the 25th International Conference on Field Programmable Logic and Applications (FPL), (2015); Rajaei R., Radiation hardened design of nonvolatile MRAM-based FPGA, IEEE Transactions on Magnetics, 52, 10, pp. 1-10, (2016); Zhao W., Belhaire E., Chappert C., Mazoyer P., Spin transfer torque (STT)-MRAM based run time reconfiguration FPGA circuit, ACM Transactions on Embedded Computing Systems, 9, 2, (2009); Ren F., Markovic D., True energy-performance analysis of the mtj-based logic-in-memory architecture (1-Bit Full Adder), IEEE Transactions on Electron Devices, 57, 5, pp. 1023-1028, (2010); Rajaei R., Highly reliable and low-power magnetic full-adder designs for nanoscale technologies, Microelectronics Reliability (MR), 73, pp. 129-135, (2017); Deng E., Wang Y., Wang Z., Klein J.O., Dieny B., Prenat G., Zhao W., Robust magnetic full-adder with voltage sensing 2T/2MTJ cell, IEEE/ACM International Conference Symposium on Nanoscale Architectures, (2015); Deng E., Zhang Y., Klein J.O., Ravelsona D., Chappert C., Zhao W., Low power magnetic full-adder based on spin transfer torque MRAM, IEEE Transactions on Magnetics, 49, 9, pp. 4982-4987, (2013); Rajaei R., Bakhtavari S., Ultra-low power, highly reliable, and nonvolatile hybrid MTJ/CMOS based full-adder for future VLSI design, IEEE Transactions on Device and Materials Reliability (TDMR), 17, 1, pp. 213-220, (2017); Wolf S.A., Awschalom D.D., Buhrman R.A., Daughton J.M., Von Molnar S., Roukes M.L., Chtchelkanova A.Y., Treger D.M., Spintronics: A spin-based electronics vision for the future, Science, 294, 5546, pp. 1488-1495, (2001); Suzuki D., Natsui M., Endoh T., Ohno H., Hanyu T., Six-input lookup table circuit with 62% fewer transistors using nonvolatile logic-in-memory architecture with series/parallel-connected magnetic tunnel junctions, J. Appl. Phys., 111, 7, (2012); Rajaei R., Single event double node upset tolerance in mos/spintronic sequential and combinational logic circuits, Microelectronics Reliability (MR), 69, pp. 109-114, (2017); Wang Z., Et al., Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque, Journal of Physics D: Applied Physics, 48, 6, (2015); Panagopoulos G.D., Augustine C., Roy K., Physics-based SPICE-compatible compact model for simulating hybrid MTJ/CMOS circuits, IEEE Transactions on Electron Devices, 60, 9, pp. 2808-2814, (2013); Kim J., Chen A., Behin-Aein B., Kumar S., Wang J., Kim C.H., A technology-agnostic MTJ SPICE model with user-defined dimensions for STT-MRAM scalability studies, Custom Integrated Circuits Conference (CICC), 2015 IEEE, pp. 1-4, (2015); Kazemi M., Ipek E., Friedman E.G., Adaptive compact magnetic tunnel junction model, IEEE Transactions on Electron Devices, 61, 11, pp. 3883-3891, (2014); Predictive Technology Model for SPICE Tool","","","Institute of Electrical and Electronics Engineers Inc.","","26th Iranian Conference on Electrical Engineering, ICEE 2018","8 May 2018 through 10 May 2018","Mashhad","140232","","978-153864916-9","","","English","Iranian Conf. Electr. Eng., ICEE","Conference paper","Final","","Scopus","2-s2.0-85055658337" +"Rao S.; Shashikanth K.S.; Srinivas R.; Sunita M.S.","Rao, Sharath (57204621448); Shashikanth, K.S. (56619153700); Srinivas, Ranjith (57204620033); Sunita, M.S. (56644614100)","57204621448; 56619153700; 57204620033; 56644614100","Magnetic RAM based filter design for low power signal processing in IOT applications","2018","2017 14th IEEE India Council International Conference, INDICON 2017","","","8487647","","","","0","10.1109/INDICON.2017.8487647","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85056393097&doi=10.1109%2fINDICON.2017.8487647&partnerID=40&md5=4d6b10c0c4653c7ddf3a1409a0956ff7","Dept. of Electronics and Communication Engineering, PES University, Bangalore, 560085, India","Rao S., Dept. of Electronics and Communication Engineering, PES University, Bangalore, 560085, India; Shashikanth K.S., Dept. of Electronics and Communication Engineering, PES University, Bangalore, 560085, India; Srinivas R., Dept. of Electronics and Communication Engineering, PES University, Bangalore, 560085, India; Sunita M.S., Dept. of Electronics and Communication Engineering, PES University, Bangalore, 560085, India","Emerging memory technologies have attracted a lot of interest and has witnessed tremendous innovation in the past couple of years due to the continuous demand for greater performance by modern computing systems. This paper presents the design of Magnetic RAM (MRAM) and its implementation in memory based FIR filter. MRAM has obtained significant interest in the past decade due to its non-volatility property. MRAM stores data using spintronic device Magnetic Tunneling Junction (MTJ). In this paper a mathematical model is developed for MTJ using the LLG equation. A new configuration 3T2MTJ for MRAM is proposed and a dual port MRAM is designed using this configuration. A 9-tap FIR filter is constructed using the proposed dual port MRAM design. The performance of MRAM single cell, single and dual port multipliers and FIR filter is evaluated and compared with the conventional SRAM based system. It can be observed that dual port multiplier using MRAM reduces the power consumption by 77% as compared to SRAM based design and the power consumption in FIR filter is reduced by 37% by using MRAM in the place of SRAM. © 2017 IEEE.","FIR filter; LUT Multiplier; Magnetic RAM; Magnetic Tunneling Junction; Non-volatile memory","Electric power utilization; Integrated circuit design; Magnetic recording; Magnetic storage; Magnetism; MRAM devices; Signal processing; Static random access storage; Continuous demand; Conventional sram; Emerging memory technologies; LUT Multiplier; Magnetic rams; Magnetic tunneling junctions; Non-volatile memory; Spintronic device; FIR filters","","","","","","","Perera C., Liu C.H., Jayawardena S., Chen M., A survey on internet of things from industrial market perspective, IEEE Access, 2, pp. 1660-1679, (2014); Yu S., Chen P.Y., Emerging memory technologies: Recent trends and prospects, IEEE Solid-State Circuits Magazine, 8, 2, pp. 43-56, (2016); Cockburn B.F., Tutorial on magnetic tunnel junction magnetoresistive random-access memory, Records of the 2004 International Workshop on Memory Technology, Design and Testing, 2004., pp. 46-51, (2004); Noguchi H., Ikegami K., Shimomura N., Tetsufumi T., Ito J., Fujita S., Highly reliable and low-power nonvolatile cache memory with advanced perpendicular STT-MRAM for high-performance CPU, 2014 Symposium on VLSI Circuits Digest of Technical Papers, Honolulu, HI, pp. 1-2, (2014); Arumugam R.V., Foh C.H., Shi H., Khaing K.K., HCache: A Hybrid cache management scheme with Flash and next generation NVRAM, 2012 Digest APMRC, pp. 1-4, (2012); Vatankhahghadim A., Song W., Sheikholeslami A., A variation-tolerant mram-backed-SRAM cell for a nonvolatile dynamically reconfigurable FPGA, IEEE Transactions on Circuits and Systems II: Express Briefs, 62, 6, pp. 573-577, (2015); Liu X., Thomas T., Boguslawski A., Tessier R., Adaptive mram-based cgras, 2015 25th International Conference on Field Programmable Logic and Applications (FPL), pp. 1-4, (2015); Dorrance R., Ren F., Toriyama Y., Hafez A.A., Yang C.K.K., Markovic D., Scalability and design-space analysis of a 1t-1mtj memory cell for stt-rams, IEEE Transactions on Electron Devices, 59, 4, pp. 878-887, (2012); Chen K., Han J., Lombardi F., On the nonvolatile performance of flip-flop/SRAM cells with a single mtj, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 23, 6, pp. 1160-1164, (2015); Ryu J.W., Kwon K.W., A reliable 2t2mtj nonvolatile static gain cell stt-mram with self-referencing sensing circuits for embedded memory application, IEEE Transactions on Magnetics, 52, 4, pp. 1-10, (2016); Meher P.K., New approach to look-up-table design and memory-based realization of fir digital filter, IEEE Transactions on Circuits and Systems I: Regular Papers, 57, 3, pp. 592-603, (2010); Landau L.D., Lifshitz E.M., Theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowietunion, 8, (1935); Gilbert T.L., A lagrangian formulation of the gyromagnetic equation of the magnetic field, Physical Review, 100, (1955); Brinkman W.F., Dynes R.C., Rowell J.M., Tunneling conductance of asymmetrical barriers, J. Appl. Phys, 41, 5, pp. 1915-1921, (1970); Slonczewski J.C., Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier, Phys. Rev. B, 39, 10, pp. 6995-7002, (1989); Julliere M., Tunneling between ferromagnetic films, Phys. Lett, 54 A, 3, pp. 225-226, (1975); Lim H., Lee S., Shin H., A survey on the modeling of magnetic tunnel junctions for circuit simulation, Active and Passive Electronic Components 2016, (2016)","","","Institute of Electrical and Electronics Engineers Inc.","","14th IEEE India Council International Conference, INDICON 2017","15 December 2017 through 17 December 2017","Roorkee","140717","","978-153864318-1","","","English","IEEE India Council Int. Conf., INDICON","Conference paper","Final","","Scopus","2-s2.0-85056393097" +"He Z.; Fan D.","He, Zhezhi (57194287525); Fan, Deliang (55778301000)","57194287525; 55778301000","A Low Power Current-Mode Flash ADC with Spin Hall Effect based Multi-Threshold Comparator","2016","Proceedings of the International Symposium on Low Power Electronics and Design","","","","314","319","5","17","10.1145/2934583.2934642","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85021185790&doi=10.1145%2f2934583.2934642&partnerID=40&md5=ab4332ecffceae548020b90bf508a90c","Dept. of Electrical and Computer Engineering, University of Central Florida, Orlando, FL, United States","He Z., Dept. of Electrical and Computer Engineering, University of Central Florida, Orlando, FL, United States; Fan D., Dept. of Electrical and Computer Engineering, University of Central Florida, Orlando, FL, United States","Current-mode Analog-to-Digital Converter (ADC) has drawn many attentions due to its high operating speed, power and ground noise immunity, and etc. However, 2n - 1 comparators are required in traditional n-bit current-mode ADC design, leading to inevitable high power consumption and large chip area. In this work, we propose a low power and compact current mode Multi-Threshold Comparator (MTC) based on giant Spin Hall Effect (SHE). The two threshold currents of the proposed SHE-MTC are 200μA and 250μA with 1ns switching time, respectively. The proposed current-mode hybrid spin-CMOS flash ADC based on SHE-MTC reduces the number of comparators almost by half (2n-1), thus correspondingly reducing the required current mirror branches, total power consumption and chip area. Moreover, due to the non-volatility of SHE-MTC, the front-end analog circuits can be switched off when it is not required to further increase power efficiency. The device dynamics of SHE-MTC is simulated using a numerical device model based on Landau-Lifshitz-Gilbert (LLG) equation with Spin-Transfer Torque (STT) term and SHE term. The device-circuit co-simulation in SPICE (45nm CMOS technology) have shown that the average power dissipation of proposed ADC is 1.9mW, operating at 500MS/s with 1.2 V power supply. The INL and DNL are in the range of 0.23LSB and 0.32LSB, respectively. © 2016 ACM.","Flash ADC; multi-threshold Comparator; Spin Hall Effect","Analog to digital conversion; CMOS integrated circuits; Comparator circuits; Comparators (optical); Crystal symmetry; Electric power utilization; Low power electronics; SPICE; Spin dynamics; Analog to digital converters; FLASH-ADC; High power consumption; Landau-Lifshitz-Gilbert equations; Multithreshold; Spin transfer torque; Threshold currents; Total power consumption; Spin Hall effect","","","","","","","Augustine C., Et al., Low-power functionality enhanced computation architecture using spin-based devices, NANOARCH, (2011); Datta S., Et al., Non-volatile spin switch for boolean and non-boolean logic, APL, (2012); Fan D., Et al., Design and synthesis of ultralow energy spin-memristor threshold logic, IEEE TNANO, (2014); Fan D., Et al., Injection-locked spin hall-induced coupled-oscillators for energy efficient associative computing, IEEE TNANO, (2015); Fan D., Et al., Stt-snn: A spin-transfer-torque based soft-limiting non-linear neuron for low-power artificial neural networks, IEEE TNANO, (2015); Fong X., Et al., Spin-transfer torque devices for logic and memory: Prospects and perspectives, IEEE TCAD, (2016); Furuta M., Et al., A 10-bit, 40-ms/s, 1. 21 mw pipelined sar adc using single-ended 1. 5-bit/cycle conversion technique, IEEE JSSC, (2011); Homann A., Spin hall effects in metals, Magnetics, IEEE Transactions on, (2013); Julliere M., Tunneling between ferromagnetic films, PLA; Kim Y., Et al., Multilevel spin-orbit torque mrams, Electron Devices, IEEE Trans. on, (2015); Lee D., Et al., Fat tree encoder design for ultra-high speed flash a/d converters, MWSCAS, (2002); Liu L., Et al., Spin-torque switching with the giant spin hall effect of tantalum, Science, (2012); Manipatruni S., Et al., Energy-delay performance of giant spin hall effect switching for dense magnetic memory, APE, (2014); Murmann B., The race for the extra decibel: A brief review of current adc performance trajectories, SSC Magazine, IEEE, (2015); Pai C.-F., Et al., Spin transfer torque devices utilizing the giant spin hall effect of tungsten, APL, (2012); Panagopoulos G., Et al., A framework for simulating hybrid mtj/CMOS circuits: Atoms to system approach, DATE, (2012); Park C.-J., Et al., A current-mode flash adc for low-power continuous-time sigma delta modulators, ISCAS, (2013); Razavi B., The strongarm latch, Solid-State Circuits Magazine, IEEE, (2015); Sharad M., Et al., Energy-efficient non-boolean computing with spin neurons and resistive memory, IEEE TNANO, (2014); Shu Y.-S., A 6b 3gs/s 11mw fully dynamic flash adc in 40nm CMOS with reduced number of comparators, VLSIC, (2012); Tanifuji S., Et al., High sampling rate 1 gs/s current mode pipeline adc in 90 nm si-CMOS process, IMWS-IRFPT, (2011); Tsymbal E.Y., Theory of magnetostatic coupling in thin-film rectangular magnetic elements, APL, (2000); Yogendra K., Et al., Domain wall motion-based low power hybrid spin-CMOS 5-bit flash analog data converter, ISQED, (2015); Zhang Y., Et al., Mlc stt-ram design considering probabilistic and asymmetric mtj switching, ISCAS, (2013)","","","Institute of Electrical and Electronics Engineers Inc.","ACM SIGDA; IEEE CAS","21st IEEE/ACM International Symposium on Low Power Electronics and Design, ISLPED 2016","8 August 2016 through 10 August 2016","San Francisco","135042","15334678","978-145034185-1","","","English","Proc. Int. Symp. Low Power Electron. Des.","Conference paper","Final","","Scopus","2-s2.0-85021185790" +"Ozaki D.; Miura D.; Sakuma A.","Ozaki, Dai (56955199300); Miura, Daisuke (7005382076); Sakuma, Akimasa (7102719646)","56955199300; 7005382076; 7102719646","Theoretical Study of Gilbert Damping Constants in Magnetic Multilayer Films","2019","IEEE Transactions on Magnetics","55","7","8648534","","","","1","10.1109/TMAG.2019.2893370","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85067804596&doi=10.1109%2fTMAG.2019.2893370&partnerID=40&md5=61ce3a9d78c62961560610af5bf49642","Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan","Ozaki D., Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan; Miura D., Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan; Sakuma A., Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan","A theory is presented, describing Gilbert damping of a ferromagnetic layer by treating the outflow of the spin angular momentum to lattice and nonmagnetic systems on the same footing. The Mori formalism is applied to the entire system, including at the interface between different bulk (or film) systems. The Gilbert damping constant is determined from both Kamersky's spin-orbit-related torque correlation (TC) term and the hopping-related TC term. In addition, we confirm that the hopping-related TC term corresponds to conventional Gilbert damping enhanced by spin pumping. © 1965-2012 IEEE.","Gilbert damping; Landau-Lifshitz-Gilbert (LLG) equation; spin dynamics","Damping; Lattice theory; Magnetic multilayers; Spin dynamics; Ferromagnetic layers; Gilbert damping; Gilbert damping constant; Landau-Lifshitz-Gilbert equations; Non-magnetic system; Spin angular momentum; Theoretical study; Torque correlation; Multilayer films","","","","","Japan Society for the Promotion of Science, JSPS, (16H02390, 16K06702, 16H04322, 19H05612, 17K14800)","This work was supported in part by JSPS KAKENHI under Grant 16K06702, Grant 16H02390, Grant 16H04322, and Grant 17K14800 in Japan.","Kambersky V., Spin-orbital Gilbert damping in common magnetic metals, Phys. Rev. B, Condens. Matter, 76, 13, (2007); Gilmore K., Idzerda Y.U., Stiles M.D., Identification of the dominant precession-damping mechanism in Fe, Co, and Ni by firstprinciples calculations, Phys. Rev. Lett., 99, 2, (2007); Sakuma A., First-principles study on the Gilbert damping constants of transition metal alloys, Fe-Ni and Fe-Pt systems, J. Phys. Soc. Jpn., 81, 8, (2012); Ozaki D., Miura D., Sakuma A., First-principles study on the magnetic damping of transition metals in the presence of spin fluctuation, IEEE Trans. Magn., 53, 11, (2017); Ebert H., Mankovsky S., Kodderitzsch D., Kelly P.J., Ab initio calculation of the Gilbert damping parameter via the linear response formalism, Phys. Rev. Lett., 107, 6, (2011); Simanek E., Heinrich B., Gilbert damping in magnetic multilayers, Phys. Rev. B, Condens. Matter, 67, 14, (2003); Umetsu N., Miura D., Sakuma A., Spin-wave-induced spin torque in Rashba ferromagnets, Phys. Rev. B, Condens. Matter, 91, 17, (2015); Garate I., MacDonald A., Gilbert damping in conducting ferromagnets. II. Model tests of the torque-correlation formula, Phys. Rev. B, Condens. Matter, 79, 6, (2009); Sakuma A., Theoretical investigation on the relationship between the torque correlation and spin correlation models for the Gilbert damping constant, J. Appl. Phys., 117, 1, (2015); Mizukami S., Ando Y., Miyazaki T., The study on ferromagnetic resonance linewidth for NM/80nife/NM (NM=Cu, Ta, Pd and Pt) films, Jpn. J. Appl. Phys., 40, 2, (2001); Tserkovnyak Y., Brataas A., Bauer G.E.W., Enhanced Gilbert damping in thin ferromagnetic films, Phys. Rev. Lett., 88, (2002); Zwierzycki M., Tserkovnyak Y., Kelly P.J., Brataas A., Bauer G.E.W., First-principles study of magnetization relaxation enhancement and spin transfer in thin magnetic films, Phys. Rev. B, Condens. Matter, 71, (2005); Starikov A.A., Kelly P.J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Unified first-principles study of Gilbert damping, spinflip diffusion, and resistivity in transition metal alloys, Phys. Rev. Lett., 105, 23, (2010); Brataas A., Tserkovnyak Y., Bauer G.E.W., Scattering theory of Gilbert damping, Phys. Rev. Lett., 101, 3, (2008); Kubo R., Statistical-mechanical theory of irreversible processes. I. General theory and simple applications to magnetic and conduction problems, J. Phys. Soc. Jpn., 12, 6, pp. 570-586, (1957); Mori H., Transport, collective motion, and Brownian motion, Prog. Theor. Phys., 33, 3, pp. 423-455, (1965); Rashba E.I., Properties of semiconductors with an extremum loop. 1. Cyclotron and combinational resonance in a magnetic field perpendicular to the plane of the loop, Sov. Phys. Solid State, 2, (1960); Sakuma A., First-principles study on the non-collinear magnetic structures of disordered alloys, J. Phys. Soc. Jpn., 69, 9, pp. 3072-3083, (2000); Barati E., Cinal M., Edwards D.M., Umerski A., Gilbert damping in magnetic layered systems, Phys. Rev. B, Condens. Matter, 90, 1, (2014); Hiramatsu R., Miura D., Sakuma A., First principles calculation for Gilbert damping constants in ferromagnetic/non-magnetic junctions, AIP Adv., 8, 5, (2017)","D. Ozaki; Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan; email: ozaki@solid.apph.tohoku.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85067804596" +"Endo Y.; Mori O.; Yabukami S.; Utsumi R.; Shimada Y.","Endo, Y. (55427435300); Mori, O. (57202639360); Yabukami, S. (6603935355); Utsumi, R. (57202646682); Shimada, Y. (24725430800)","55427435300; 57202639360; 6603935355; 57202646682; 24725430800","Development of the new measurement techinque for spin dynamics of magnetic thin films","2018","2018 IEEE International Magnetic Conference, INTERMAG 2018","","","8508502","","","","0","10.1109/INTMAG.2018.8508502","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85066785412&doi=10.1109%2fINTMAG.2018.8508502&partnerID=40&md5=72646b7d62dbe461b8264d67b5ca4fa6","Department of Electrical Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan; Center for Spintronics Research Network, Tohoku University, Sendai, Japan; Toei Scientific Industrial Co Ltd., Sendai, Japan; Faculty of Engineering, Tohoku Gakuin University, Sendai, Japan","Endo Y., Department of Electrical Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan, Center for Spintronics Research Network, Tohoku University, Sendai, Japan; Mori O., Toei Scientific Industrial Co Ltd., Sendai, Japan; Yabukami S., Faculty of Engineering, Tohoku Gakuin University, Sendai, Japan; Utsumi R., Toei Scientific Industrial Co Ltd., Sendai, Japan; Shimada Y., Toei Scientific Industrial Co Ltd., Sendai, Japan","The spin dynamics in magnetic thin films have attracted much attention from both fundamental and application viewpoints. The dynamics are described using the phenomenological Landau-Lifshitz-Gilbert (LLG) equation consisting of both the precession torque of the magnetization and the damping torque. Especially, a Gilbert damping constant (a), which describes the strength of damping torque, is one of the dominant parameter to predict the dynamics. Until now, we reported the correlation between α and the saturation magnetostriction (λs) for Ni-Fe and Ni-Fe-M films[1]-[3] and found different behaviors of a depending on positive or negative values of λs. To investigate this correlation in more detail, these parameters must be estimated simultaneously for each film using a same measurement instrument. Herein, we proposed a new measurement technique, which employs a microstripe line probe to detect ferromagnetic resonance (FMR) spectra for a magnetic thin film either with tensile stress or stress free, which enables simultaneous evaluation of α and λs © 2018 IEEE.","","Binary alloys; Damping; Ferromagnetic resonance; Iron alloys; Magnetic devices; Magnetic thin films; Magnetism; Spin dynamics; Damping torques; Ferromagnetic resonance (FMR); Gilbert damping constant; Landau-Lifshitz-Gilbert equations; Measurement instruments; Measurement techniques; Negative values; Saturation magnetostriction; Thin films","","","","","","","Endo Y., Et al., J. Appl. Phys., 109, (2011); Endo Y., Et al., IEEE Trans. Magn., 47, (2011); Endo Y., Et al., IEEE Trans. Magn., 48, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","","2018 IEEE International Magnetic Conference, INTERMAG 2018","23 April 2018 through 27 April 2018","Singapore","141475","","978-153866425-4","","","English","IEEE Int. Magn. Conf., INTERMAG","Conference paper","Final","","Scopus","2-s2.0-85066785412" +"Taniguchi T.; Saida D.; Nakatani Y.; Kubota H.","Taniguchi, Tomohiro (36180180300); Saida, Daisuke (6506815927); Nakatani, Yoshinobu (7202547641); Kubota, Hitoshi (35248482000)","36180180300; 6506815927; 7202547641; 35248482000","Magnetization switching by current and microwaves","2016","Physical Review B","93","1","014430","","","","23","10.1103/PhysRevB.93.014430","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84955316135&doi=10.1103%2fPhysRevB.93.014430&partnerID=40&md5=fa4dc6483dcf00b747a2f19dab6ae557","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8568, Japan; Corporate Research and Development Center, Toshiba Corporation, Kawasaki, 212-8582, Japan; Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8568, Japan; Saida D., Corporate Research and Development Center, Toshiba Corporation, Kawasaki, 212-8582, Japan; Nakatani Y., Graduate School of Informatics and Engineering, University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan; Kubota H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8568, Japan","We propose a theoretical model of magnetization switching in a ferromagnetic multilayer by both electric current and microwaves. The electric current gives a spin transfer torque on the magnetization, while the microwaves induce a precession of the magnetization around the initial state. Based on numerical simulation of the Landau-Lifshitz-Gilbert (LLG) equation, it is found that the switching current is significantly reduced compared with the switching caused solely by the spin transfer torque when the microwave frequency is in a certain range. We develop a theory of switching from the LLG equation averaged over a constant energy curve. It was found that the switching current should be classified into four regions, depending on the values of the microwave frequency. Based on the analysis, we derive an analytical formula of the optimized frequency minimizing the switching current, which is smaller than the ferromagnetic resonance frequency. We also derive an analytical formula of the minimized switching current. Both the optimized frequency and the minimized switching current decrease with increasing the amplitude of the microwave field. The results will be useful to achieve high thermal stability and low switching current in spin torque systems simultaneously. © 2016 American Physical Society.","","","","","","","","","Hubert A., Schafer R., Magnetic Domains, (1998); Slonczewski J.C., Phys. Rev. B, 39, (1989); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Grollier J., Cros V., Hamzic A., George J.M., Jaffres H., Fert A., Faini G., Youssef J.B., Gall H.L., Appl. Phys. Lett., 78, (2001); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature (London), 425, (2003); Grollier J., Cros V., Jaffres H., Hamzic A., George J.M., Faini G., Youssef J.B., LeGall H., Fert A., Phys. Rev. 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Express, 2, (2009); Endo M., Kanai S., Ikeda S., Matsukura F., Ohno H., Appl. Phys. Lett., 96, (2010); Nozaki T., Shiota Y., Shiraishi M., Shinjo T., Suzuki Y., Appl. Phys. Lett., 96, (2010); Chiba D., Fukami S., Shimamura K., Ishiwata N., Kobayashi K., Ono T., Nat. Mater., 10, (2011); Wang W.-G., Li M., Hageman S., Chien C.L., Nat. Mater., 11, (2011); Shiota Y., Murakami S., Bonell F., Nozaki T., Shinjo T., Suzuki Y., Appl. Phys. Express, 4, (2011); Nozaki T., Shiota Y., Miwa S., Murakami S., Bonell F., Ishibashi S., Kubota H., Yakushiji K., Saruya T., Fukushima A., Et al., Nat. Phys., 8, (2012); Pertsev N., Sci. Rep., 3, (2013); Oogane M., Wakitani T., Yakata S., Yilgin R., Ando Y., Sakuma A., Miyazaki T., Jpn. J. Appl. Phys., 45, (2006); Bonin R., Bertotti G., Serpico C., Mayergoyz I.D., D'Aquino M., Eur. Phys. J. B, 68, (2009); D'Aquino M., Serpico C., Bonin R., Bertotti G., Mayergoyz I.D., J. Appl. Phys., 109, (2011); Suto H., Kudo K., Nagasawa T., Kanao T., Mizushima K., Sato R., Okamoto S., Kikuchi N., Kitakami O., Phys. Rev. B, 91, (2015); Taniguchi T., Appl. Phys. Express, 8, (2015); Bertotti G., Mayergoyz I.D., Serpico C., J. Appl. Phys., 95, (2004); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., D'Aquino M., Bonin R., Phys. Rev. Lett., 94, (2005); Bertotti G., Serpico C., Mayergoyz I.D., Bonin R., D'Aquino M., J. Magn. Magn. Mater., 316, (2007); Serpico C., D'Aquino M., Bertotti G., Mayergoyz I.D., J. Appl. Phys., 95, (2004); Serpico C., D'Aquino M., Bertotti G., Mayergoyz I.D., J. Magn. Magn. Mater., 290, (2005); Serpico C., Bertotti G., Mayergoyz I.D., D'Aquino M., Bonin R., J. Appl. Phys., 99, (2006); Hillebrands B., Thiaville A., Spin Dynamics in Confined Magnetic Structures III, (2006); Bazaliy Y.B., Arammash F., Phys. Rev. B, 84, (2011); Bazaliy Y.B., J. Appl. Phys., 110, (2011); Dykman M., Fluctuating Nonlinear Oscillators, (2012); Newhall K.A., Eijnden E.V., J. Appl. Phys., 113, (2013); Taniguchi T., Utsumi Y., Marthaler M., Golubev D.S., Imamura H., Phys. Rev. B, 87, (2013); Taniguchi T., Utsumi Y., Imamura H., Phys. Rev. B, 88, (2013); Lacoste B., Buda-Prejbeanu L.D., Ebels U., Dieny B., Phys. Rev. B, 88, (2013); Taniguchi T., Arai H., Tsunegi S., Tamaru S., Kubota H., Imamura H., Appl. Phys. Express, 6, (2013); Pinna D., Kent A.D., Stein D.L., Phys. Rev. B, 88, (2013); Pinna D., Stein D.L., Kent A.D., Phys. Rev. B, 90, (2014); Taniguchi T., Phys. Rev. B, 91, (2015); Dyakonov M.I., Perel V.I., Phys. Lett. A, 35, (1971); Hirsch J.E., Phys. Rev. Lett., 83, (1999); Kato Y.K., Myers R.C., Gossard A.C., Awschalom D.D., Science, 306, (2004); Maekawa S., Concepts in Spin Electronics, (2006); Liu L., Lee O.J., Gudmundsen T.J., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 109, (2012); Lee K.-S., Lee S.-W., Min B.-C., Lee K.-J., Appl. Phys. Lett., 102, (2013); Sun Z.Z., Wang X.R., Phys. Rev. B, 73, (2006)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84955316135" +"Yao Z.; Cui H.; Tok R.U.; Wang Y.E.","Yao, Zhi (56380891100); Cui, Han (55774086800); Tok, Rustu Umut (37862036500); Wang, Yuanxun Ethan (57202387207)","56380891100; 55774086800; 37862036500; 57202387207","3D multiscale unconditionally stable time-domain modeling of nonlinear rf thin film magnetic devices","2019","2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019 - Proceedings","","","8888765","1059","1060","1","0","10.1109/APUSNCURSINRSM.2019.8888765","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85075239195&doi=10.1109%2fAPUSNCURSINRSM.2019.8888765&partnerID=40&md5=b9ad2395fe61a1fc337b837534b97fe3","University of California, Electrical and Computer Engineering Department, Los Angeles, United States","Yao Z., University of California, Electrical and Computer Engineering Department, Los Angeles, United States; Cui H., University of California, Electrical and Computer Engineering Department, Los Angeles, United States; Tok R.U., University of California, Electrical and Computer Engineering Department, Los Angeles, United States; Wang Y.E., University of California, Electrical and Computer Engineering Department, Los Angeles, United States","An unconditionally stable three-dimensional (3D) finite-difference time-domain (FDTD) algorithm has been proposed to solve simultaneously Maxwell's equations and the Landau-Lifshitz-Gilbert (LLG) equation with full nonlinear effects. The proposed algorithm can predict the dynamic interaction between magnetic spins and EM fields. The accuracy of the modeling has been validated by 1. Small signal simulation of a linear ferrite isolator and 2. Large signal simulation of the dispersive permeability of a continuous ferrite film. The simulations agree with the theoretical and experimental predictions, under both linear and nonlinear circumstances. Specifically, the algorithm has fully revealed that sufficiently large RF power can decrease the ferromagnetic resonance (FMR) frequency and suppress the permeability. © 2019 IEEE.","Electromagnetics; Finite difference time domain methods; Landau-Lifshitz-Gilbert equation; Magnetic thin films; Multiphysics; Nonlinear problems; Unconditionally stable methods","","","","","","NSF Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems; TANMS, (EEC-1160504); Defense Advanced Research Projects Agency, DARPA, (M3IC, W911NF-17-1-0100); Defense Advanced Research Projects Agency, DARPA","This work was supported by the Defense Advanced Research Projects Agency (DARPA) Magnetic Miniaturized and Monolithically Integrated Components (M3IC) Program under award W911NF-17-1-0100 and by the NSF Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS) under Cooperative Agreement Award EEC-1160504.","Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proceedings of the IRE, 44, 10, pp. 1270-1284, (1956); Zheng F., Chen Z., Zhang J., Toward the development of a threedimensional unconditionally stable finite-difference time-domain method, IEEE Trans. Microwave Theory and Techniques, 48, 9, pp. 1550-1558, (2000); Namiki T., A new fdtd algorithm based on alternating-direction implicit method, IEEE Trans. Microwave Theory and Techniques, 47, 10, pp. 2003-2007, (1999); Yao Z., Tok R.U., Itoh T., Wang Y.E., A multiscale unconditionally stable time-domain (must) solver unifying electrodynamics and micromagnetics, IEEE Transactions on Microwave Theory and Techniques, 66, pp. 2683-2696, (2018); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, Journal of Computational and Applied Mathematics, 176, 2, pp. 263-281, (2005); Bernardi P., Valdoni F., Fundamentals of a new class of magnetically tunable waveguide filters, IEEE Transactions on Magnetics, 2, 3, pp. 264-268, (1966); Uher J., Arndt F., Bornemann J., Field theory design of ferriteloaded waveguide nonreciprocal phase shifters with multisection ferrite or dielectric slab impedance transformers, IEEE Trans. Microw. Theory Tech., 35, 6, pp. 552-560, (1987)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (APS); The Institute of Electrical and Electronics Engineers (IEEE)","2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019","7 July 2019 through 12 July 2019","Atlanta","153911","","978-172810692-2","","","English","IEEE Int. Symp. Antennas Propag. USNC-URSI Radio Sci. Meet., APSURSI - Proc.","Conference paper","Final","","Scopus","2-s2.0-85075239195" +"Hane Y.; Nakamura K.; Ohinata T.; Arimatsu K.","Hane, Yoshiki (36632081800); Nakamura, Kenji (55516112700); Ohinata, Takashi (15045419600); Arimatsu, Kenji (15043532100)","36632081800; 55516112700; 15045419600; 15043532100","Reluctance Network Model of Three-Phase-Laminated-Core Variable Inductor Considering Magnetic Hysteresis Behavior","2019","IEEE Transactions on Magnetics","55","7","8672590","","","","7","10.1109/TMAG.2019.2900527","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85067824488&doi=10.1109%2fTMAG.2019.2900527&partnerID=40&md5=94933fe67bec5656654af34a679d914c","Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan; Tohoku Electric Power Co., Inc., Sendai, 980-8550, Japan","Hane Y., Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan; Ohinata T., Tohoku Electric Power Co., Inc., Sendai, 980-8550, Japan; Arimatsu K., Tohoku Electric Power Co., Inc., Sendai, 980-8550, Japan","The quantitative analysis of the iron loss taking magnetic hysteresis behavior into account is essential for the development of high-efficiency electric machines. In a previous paper, a novel magnetic circuit model incorporating a play model, which is one of the phenomenological models of magnetic hysteresis, was proposed. It was clear that the proposed model can calculate the hysteresis loop of a ring core with high speed and high accuracy. However, this method was applied only for the objects with simple shapes. Thus, it is necessary to extend the applicable range for the objects with more complicated shapes. This paper presents a novel reluctance network analysis (RNA) model incorporating the play model and indicates the validity of the proposed RNA model by using a three-phase-laminated-core variable inductor as an object of discussion. © 1965-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; play model; reluctance network analysis (RNA); three-phase-laminated-core variable inductor","Electric inductors; Electric losses; Laminating; Magnetic hysteresis; Magnetic materials; Magnetism; RNA; Laminated core; Landau-Lifshitz-Gilbert equations; Magnetic circuit model; Phenomenological models; Play model; Reluctance network analysis; Reluctance network analysis models; Variable inductors; Magnetic circuits","","","","","","","Fukuda H., Nakatani Y., Recording density limitation explored by head/media co-optimization using genetic algorithm and GPUaccelerated LLG, IEEE Trans. Magn., 48, 11, pp. 3895-3898, (2012); Oshima H., Et al., Experimental and simulation modeling studies of magnetic properties of Ni-Zn ferrite cores under DC bias, J. Jpn. Soc. Powder Powder Metall., 61, pp. S238-S241, (2014); Tanaka H., Nakamura K., Ichinokura O., Calculation of iron loss in soft ferromagnetic materials using magnetic circuit model taking magnetic hysteresis into consideration, J. Magn. Soc. Jpn., 39, 2, pp. 65-70, (2015); Tanaka H., Nakamura K., Ichinokura O., Accuracy improvement of magnetic hysteresis calculated by LLG equation, J. Phys., Conf. Ser., 903, 1, (2017); Bobbio S., Milano G., Serpico C., Visone C., Models of magnetic hysteresis based on play and stop hysterons, IEEE Trans. Magn., 33, 6, pp. 4417-4426, (1997); Tanaka H., Nakamura K., Ichinokura O., Magnetic circuit model combined with play model obtained from landau-Lifshitz-Gilbert equation, J. Phy., Conf. Ser., 903, 1, (2017); Nakamura K., Ichinokura O., Reluctance network based dynamic analysis in power magnetics, IEEJ Trans. Fundam. Mater., 128, 8, pp. 506-510, (2008); Nakamura K., Kimura K., Ichinokura O., Electromagnetic and motion-coupled analysis for switched reluctance motor based on reluctance network analysis, J. Magn. Magn. Mater., 290-291, pp. 1309-1312, (2005); Fukuoka M., Nakamura K., Ichinokura O., Dynamic analysis of planetary-type magnetic gear based on reluctance network analysis, IEEE Trans. Magn., 47, 10, pp. 2414-2417, (2011); Nakamura K., Honma K., Ohinata T., Arimatsu K., Shirasaki T., Ichinokura O., Basic characteristics of lap-winding type three-phase laminated-core variable inductor, J. Magn. Soc. Jpn., 38, 4, pp. 174-177, (2014); Nakamura K., Hisada S., Arimatsu K., Ohinata T., Sakamoto K., Ichinokura O., Development of a novel three-phase laminated-core variable inductor for Var compensation, IEEE Trans. Magn., 44, 11, pp. 4107-4110, (2008); Wanlass S.D., The paraformer, a new passive power conversion device, Proc. IEEE WESCON, (1968); Ichinokura O., Jinzenji T., Tajima K., A new variable inductor for VAR compensation, IEEE Trans. Magn., 29, 6, pp. 3225-3227, (1993); Yoshida Y., Nakamura K., Ichinokura O., Eddy current loss calculation in permanent magnet of SPM motor including carrier harmonics based on reluctance network analysis, J. Magn. Soc. Jpn., 37, 3, pp. 278-281, (2013)","Y. Hane; Graduate School of Engineering, Tohoku University, Sendai, 980-8579, Japan; email: yoshiki.hane@ecei.tohoku.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85067824488" +"Choi D.; Choi M.; Kim J.","Choi, Donchul (56438502100); Choi, Moosung (56438500800); Kim, Jongryoul (58166414700)","56438502100; 56438500800; 58166414700","Effect of Organic Fuel on High-Frequency Magnetic Properties of Fe-Al2O3 Composite Powders Synthesized by a Combustion Method","2015","IEEE Transactions on Magnetics","51","11","7117416","","","","4","10.1109/TMAG.2015.2441115","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84946135499&doi=10.1109%2fTMAG.2015.2441115&partnerID=40&md5=f15d2fb9c8921b31eb628305e5da9d72","Department of Metallurgical and Materials Engineering, Hanyang University, Ansan, 426-791, South Korea","Choi D., Department of Metallurgical and Materials Engineering, Hanyang University, Ansan, 426-791, South Korea; Choi M., Department of Metallurgical and Materials Engineering, Hanyang University, Ansan, 426-791, South Korea; Kim J., Department of Metallurgical and Materials Engineering, Hanyang University, Ansan, 426-791, South Korea","Nanocrystalline Fe-Al2O3 soft-magnetic composite powders were synthesized by a conventional combustion method followed by a H2 reduction process. In this paper, we analyzed the effect of the types and compositions of organic fuel on the dispersive magnetic properties of the composite powders for improving the soft-magnetic properties. To understand the properties, the microstructural and thermal characterization of as-synthesized oxide powders and their reduced powders were analyzed by an X-ray diffractor, a scanning electron microscope, and a thermogravimetric and differential thermal analyzer. In addition, the high-frequency dispersive magnetic simulation using the Landau-Lifshitz-Gilbert (LLG) equation and extended Maxwell-Garnet effective medium theory mixing rule was carried out. As a result, the microstructural and thermal analyses showed that the high-frequency dispersive magnetic behaviors of nanocrystalline Fe-Al2O3 composite powders were dependent on the types and the compositions of fuel by controlling the released heat amount during the combustion redox reaction. In particular, a relative real permeability (u- r ) of 3.6 at 1 GHz was obtained in Fe-Al2O3 (Fe:Al = 95:5, wt%) composite powders combusted by a mixed fuel composed of a 50 mol% glycine and a 50 mol% urea. © 1965-2012 IEEE.","combustion; Fe-Al2O3 composite powder; high-frequency soft magnetic property; soft magnetic composite","Aluminum; Amino acids; Combustion; Differential thermal analysis; Fuels; Magnetic properties; Magnetism; Maxwell equations; Nanocrystals; Powders; Redox reactions; Scanning electron microscopy; Thermoanalysis; Urea; Composite powders; Conventional combustions; Differential thermal analyzers; Effective medium theories; Landau-Lifshitz-Gilbert equations; Soft magnetic composites; Soft magnetic properties; Thermal characterization; Nanocrystalline powders","","","","","","","Choi D., Choi M., Kim J., Magnetic properties of Fe@FeSiAl oxide nanoparticles and magneto-dielectric properties of their composite sheets, IEEE Trans. Magn, 50, 11, (2014); Hansen R.C., Burke M., Antennas with magneto-dielectrics, Microw. Opt. Technol. Lett, 26, 2, pp. 75-78, (2000); Swann P.R., Duff W.R., Fisher R.M., Electron metallography of a non-classical order-Disorder transition, Phys. Status Solidi B, 37, 2, pp. 577-583, (1970); Swann P.R., Granas L., Lehtinen B., The B2 and DO3 ordering reactions in iron-silicon alloys in the vicinity of the curie temperature, Met. Sci, 9, 1, pp. 90-96, (1975); Brown D., Holt C., Thompson J.E., Technical assessment of 6. 5 %(wt. ) silicon iron for possible application in power transformers, Proc. Inst. Elect. Eng, 111, 11, pp. 1933-1936, (1964); Yaghtin M., Taghvaei A., Hashemi B., Janghorban K., Structural and magnetic properties of Fe-Al2O3 soft magnetic composites prepared using the sol-gel method, Int. J. Mater. Res, 105, 5, pp. 474-479, (2014); Mukasyan A.S., Epstein P., Dinka P., Solution combustion synthesis of nanomaterials, Proc. Combustion Inst, 31, 2, pp. 1789-1795, (2007); Varma A., Mukasyan A.S., Deshpande K.T., Pranda P., Erri P.R., Combustion synthesis of nanoscale oxide powders: Mechanism, characterization and properties, Proc. Mat. Res. Soc. Symp, 800, pp. 113-124, (2003); Jain S.R., Adiga K.C., Verneker V.R.P., A new approach to thermochemical calculations of condensed fuel-oxidizer mixtures, Combustion Flame, 40, 6, pp. 71-79, (1981); Deshpande K., Mukasyan A., Varma A., Direct synthesis of iron oxide nanopowders by the combustion approach: Reaction mechanism and properties, Chem. Mater, 16, 24, pp. 4896-4904, (2004); Wieczorek-Ciurowa K., Kozak A.J., The thermal decomposition of Fe(NO3)39H2O, J. Thermal Anal. Calorimetry, 58, 3, pp. 647-651, (1999)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84946135499" +"Barangi M.; Mazumder P.","Barangi, Mahmood (55585398400); Mazumder, Pinaki (35586470500)","55585398400; 35586470500","Modeling of temperature dependency of magnetization in straintronics memory devices","2015","International Conference on Simulation of Semiconductor Processes and Devices, SISPAD","2015-October","","7292309","262","265","3","0","10.1109/SISPAD.2015.7292309","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84959372204&doi=10.1109%2fSISPAD.2015.7292309&partnerID=40&md5=97740e284af2fe2a09fd2f0bb5c718d1","Department of EECS, Univ. of Mich., Ann Arbor, 48109, MI, United States","Barangi M., Department of EECS, Univ. of Mich., Ann Arbor, 48109, MI, United States; Mazumder P., Department of EECS, Univ. of Mich., Ann Arbor, 48109, MI, United States","While a tremendous amount of work has been dedicated to the study of Langevin thermal noise field in spintronics magnetic tunneling junction (MTJ), a comprehensive model that predicts both static and dynamic responses of the magnetization due to temperature variations is yet to exist. In this work, we will first study the dependency of the saturation magnetization on temperature. We will then analyze the variations of the shape anisotropy and energy barrier of the straintronics MTJ on temperature. Lastly, we will incorporate these dependencies, along with the well-studied Langevin thermal field into the LLG equation to simulate the dynamic and static behavior of the straintronics devices. © 2015 IEEE.","","Magnetic devices; Magnetization; Semiconductor devices; Comprehensive model; Magnetic tunneling junctions; Shape anisotropy; Static and dynamic response; Static behaviors; Temperature dependencies; Temperature variation; Thermal field; Saturation magnetization","","","","","NSF NEB, (ECCS-1124714, PT106594-SC103006); Air Force Office of Scientific Research, AFOSR, (FA9550-12-1-0402)","This work was done partially under NSF NEB grant ECCS-1124714 (PT106594-SC103006) and partially under AFOSR grant FA9550-12-1-0402.","Moore G.E., Cramming more components onto integrated circuits, Reprinted from Electronics, volume 38, number 8, April 19, 1965, Solid-State Circuits Society Newsletter, IEEE, 11, 5, pp. 33-35, (2006); Julliere M., Tunneling between ferromagnetic films, Physics Letters A, 54, 3, pp. 225-226, (1975); Slonczewski J., Current driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, (1996); Barangi M., Mazumder P., Straintronics-based magnetic tunneling junction: Dynamic and static behavior analysis and material investigation, Appl. Phys. Lett, 104, 16, (2014); Roy K., Bandopadhyay S., Atulasimha J., Hybrid Spintronics and Straintronics: A magnetic technology for ultra-low energy computing and signal processing, Appl. Phys. Lett, 99, (2011); Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using electrically induced rotation of magnetization in multiferroic single-domain nanomagnets, Appl. Phys. Lett, 97, (2010); Kim S.-K., Shin S.-C., No K., Voltage control of magnetization easy-axes: A potential candidate for spin switching in future ultrahigh-density nonvolatile magnetic random access memory, Magnetics, IEEE Transactions on, 40, 4, pp. 2637-2639, (2004); Lei N., Devolder T., Angus G., Aubert P., Daniel L., Kim J., Zhao W., Trypiniotis T., Cowburn R.P., Chappert C., Ravelosona D., Lecoeur P., Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures, Nature Communications, 4, (2013); Khan A., Khan A., Nikonov D.E., Manipatruni S., Ghani T., Young I.A., Voltage induced magnetostrictive switching of nanomagnets: Strain assisted strain transfer torque random access memory, Applied Physics Letters, 104, 26, pp. 262407-2624075, (2014); Barangi M., Mazumder P., Straintronics-based random access memory as universal data storage devices, Magnetics, IEEE Transactions on, 51, 5, pp. 1-8, (2015); Sun J.Z., Et al., Spin angular momentum transfer in a currentperpendicular spin valve nanomagnet, Proceedings of SPIE, 5359, (2004); Nigam A., Et al., Delivering on the promise of universal memory for spin-transfer torque RAM (STT-RAM), ISLPED 2011, pp. 121-126, (2011); Chikazumi S., Physics of Ferromagnetism, (1997); Manipatruni S., Nikonov D.E., Young I.A., Modeling and design of spintronic integrated circuits, Circuits and Systems I: Regular Papers, IEEE Transactions on, 59, 12, pp. 2801-2814, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","COOLCAD Electronics; et al.; IBM; Intel; Micron; Quantum Wise","20th International Conference on Simulation of Semiconductor Processes and Devices, SISPAD 2015","9 September 2015 through 11 September 2015","Washington","118415","","978-146737858-1","","","English","Int Conf Simul Semicond Process Dev Proc SISPAD","Conference paper","Final","","Scopus","2-s2.0-84959372204" +"Hane Y.; Nakamura K.","Hane, Yoshiki (36632081800); Nakamura, Kenji (55516112700)","36632081800; 55516112700","Reluctance network model of permanent magnet synchronous motor considering magnetic hysteresis behavior","2018","2018 IEEE International Magnetic Conference, INTERMAG 2018","","","8508115","","","","7","10.1109/INTMAG.2018.8508115","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85057496216&doi=10.1109%2fINTMAG.2018.8508115&partnerID=40&md5=da37611ced20a90a003638258b4a3213","Graduate School of Engineering 6-6-11, Tohoku University, Aoba Aramaki Aoba-ku, Sendai, 980-8579, Japan","Hane Y., Graduate School of Engineering 6-6-11, Tohoku University, Aoba Aramaki Aoba-ku, Sendai, 980-8579, Japan; Nakamura K., Graduate School of Engineering 6-6-11, Tohoku University, Aoba Aramaki Aoba-ku, Sendai, 980-8579, Japan","Quantitative analysis of iron loss taking magnetic hysteresis behavior into account is essential to development of high-efficiency electric machines. In a previous paper, a novel magnetic circuit model incorporating a play model, which is one of the phenomenological models of magnetic hysteresis, was proposed. It was clear that the proposed model can calculate the hysteresis loop of the magnetic reactor with high-speed and high-accuracy. However, this method was applied only for the objects with simple shapes such as a ring core. Thus, it is necessary to extend the applicable range for devices with more complicated shapes such as electric motors. This paper describes that the play model is applied to reluctance network analysis (RNA) by using a permanent magnet (PM) motor as an object of discussion, in order to estimate the iron loss including magnetic hysteresis behavior. © 2018 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Play model; Reluctance network analysis (RNA); Surface permanent magnet (SPM) motor","Electric losses; Iron; Iron analysis; Magnetic circuits; Magnetic hysteresis; Magnetic materials; Magnetism; Permanent magnets; RNA; Synchronous motors; Landau-Lifshitz-Gilbert equations; Magnetic circuit model; Permanent magnet motor; Permanent Magnet Synchronous Motor; Phenomenological models; Play model; Reluctance network analysis; Surface permanent magnet motors; Electric machine theory","","","","","","","Fukuda H., Nakatani Y., Recording density limitation explored by head/media co-optimization using genetic algorithm and GPU accelerated LLG, IEEE Trans. Magn., 48, 11, pp. 3895-3898, (2012); Oshima H., Uehara Y., Inagaki K., Furuya A., Fujisaki J., Suzuki M., Kawano K., Mifune T., Matsuo T., Watanabe K., Igarashi H., Experimental and simulation modeling studies of magnetic properties of Ni-Zn ferrite cores under DC bias, J. Jpn. Soc. Powder Metallurgy, 61, pp. S238-S241, (2014); Tanaka H., Nakamura K., Ichinokura O., Calculation of iron loss in soft ferromagnetic materials using magnetic circuit model taking magnetic hysteresis into consideration, Journal of the Magnetics Society of Japan, 39, 2, pp. 65-70, (2015); Tanaka H., Nakamura K., Ichinokura O., Accuracy improvement of magnetic hysteresis calculated by LLG equation, Journal of Physics: Conf. Series, 903, (2017); Bobbio S., Miano G., Serpico C., Visone C., Models of magnetic hysteresis based on play and stop hysteresis, IEEE Trans. Magn., 33, 6, pp. 4417-4426, (1997); Tanaka H., Nakamura K., Ichinokura O., Magnetic circuit model combined with play model obtained from Landau-Lifshitz-Gilbert equation, Journal of Physics: Conf. Series, 903, (2017); Nakamura K., Ichinokura O., Reluctance network based dynamic analysis in power magnetics, IEEJ Trans. FM, 128, 8, pp. 506-510, (2008); Nakamura K., Kimura K., Ichinokura O., Electromagnetic and motion coupled analysis for switched reluctance motor based on reluctance network analysis, Journal of Magnetism and Magnetic Materials, 290-291, pp. 1309-1312, (2005); Fukuoka M., Nakamura K., Ichinokura O., Dynamic analysis of planetary-type magnetic gear based on reluctance network analysis, IEEE Trans. Magnetics, 47, 10, pp. 2414-2417, (2011); Nakamura K., Honma K., Ohinata T., Arimatsu K., Shirasaki T., Ichinokura O., Basic characteristics of lap-winding type three-phase laminated-core variable inductor, Journal of the Magnetics Society of Japan, 38, 4, pp. 174-177, (2014); Yoshida Y., Nakamura K., Ichinokura O., Eddy current loss calculation in permanent magnet of SPM motor including carrier harmonics based on reluctance network analysis, Journal of the Magnetics Society of Japan, 37, 3, pp. 278-281, (2013)","","","Institute of Electrical and Electronics Engineers Inc.","","2018 IEEE International Magnetic Conference, INTERMAG 2018","23 April 2018 through 27 April 2018","Singapore","141475","","978-153866425-4","","","English","IEEE Int. Magn. Conf., INTERMAG","Conference paper","Final","","Scopus","2-s2.0-85057496216" +"Yao Z.; Tok R.U.; Itoh T.; Wang Y.E.","Yao, Zhi (56380891100); Tok, Rustu Umut (37862036500); Itoh, Tatsuo (36041035600); Wang, Yuanxun Ethan (35194804700)","56380891100; 37862036500; 36041035600; 35194804700","A Multiscale Unconditionally Stable Time-Domain (MUST) Solver Unifying Electrodynamics and Micromagnetics","2018","IEEE Transactions on Microwave Theory and Techniques","66","6","","2683","2696","13","28","10.1109/TMTT.2018.2825373","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85046497570&doi=10.1109%2fTMTT.2018.2825373&partnerID=40&md5=7604eb46db0f45e89fe252db42b0cbf4","Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, CA, United States","Yao Z., Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, CA, United States; Tok R.U., Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, CA, United States; Itoh T., Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, CA, United States; Wang Y.E., Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, CA, United States","A rigorous yet computationally efficient 3-D numerical method has been proposed based on modified alternating-direction-implicit finite-difference time-domain (ADI FDTD) methods. It has the capability of modeling the anisotropic and dispersive properties of magnetic material. The proposed algorithm solves Maxwell's equations and Landau-Lifshitz-Gilbert equation jointly and simultaneously, requiring only tridiagonal matrix inversion as in ADI FDTD. The accuracy of the modeling has been validated by: 1) the nonreciprocity of an X-band ferrite resonance isolator; 2) the attenuation constant of a magnetically tunable waveguide filter; and 3) the dispersive permeability of a 2- μ m -thick magnetic thin film. Time steps that are up to 5000 times larger than the Courant-Friedrichs-Lewy limit have been used in these simulations without encountering stability issues. The simulation results agree with the predictions made from the theory, the commercial software or the experiments. Moreover, the algorithm has been applied to predict the effect of high permeability thin films in platform effect reduction. An electric current sheet close to a perfect electrically conducting plane coated with a 2- μ m -thick magnetic thin film is simulated, which exhibits an enhanced surface resistance by three orders of magnitude higher than that without the magnetic thin film. © 1963-2012 IEEE.","Dispersive permeability; electrodynamics; finite-difference time-domain (FDTD) methods; Landau-Lifshitz-Gilbert (LLG) equation; magnetic material; micromagnetics; multiphysics; thin films; unconditionally stable methods","Computer software; Electrodynamics; Finite difference method; Finite difference time domain method; Magnetic devices; Magnetic domains; Magnetic materials; Magnetic resonance; Magnetic thin films; Magnetization; Mathematical models; Matrix algebra; Maxwell equations; Numerical methods; Thin films; Waveguide filters; Dispersive permeability; Landau-Lifshitz-Gilbert equations; Magnetomechanical effects; Micromagnetics; Multi-physics; Unconditionally stable methods; Time domain analysis","","","","","National Science Foundation, NSF, (EEC-1160504); National Science Foundation, NSF; Defense Advanced Research Projects Agency, DARPA","Manuscript received October 20, 2017; revised January 25, 2018; accepted March 7, 2018. Date of publication May 4, 2018; date of current version June 4, 2018. This work was supported in part by the DARPA Magnetic Miniaturized and Monolithically Integrated Components (M3IC) Program and in part by the NSF Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems under Cooperative Agreement Award EEC-1160504. (Corresponding author: Yuanxun Ethan Wang.) The authors are with the Electrical Engineering Department, University of California at Los Angeles, Los Angeles, CA 90024 USA (e-mail: zhiyao@ucla.edu; ywang@ee.ucla.edu).","Wu M., Hoffmann A., Ferrites for RF passive devices, Solid State Physics, 64, pp. 237-326, (2013); Harris V.G., Modern microwave ferrites, IEEE Trans. Magn., 48, 3, pp. 1075-1104, (2012); Lax B., Button K.J., Microwave Ferrites and Ferrimagnetics, (1962); Pozar D.M., Microwave Engineering, pp. 441-485, (2005); Yao Z., Wang Y.E., Keller S., Carman G.P., Bulk acoustic wave-mediated multiferroic antennas: Architecture and performance bound, IEEE Trans. Antennas Propag., 63, 8, pp. 3335-3344, (2015); Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proc. IRE, 44, 10, pp. 1270-1284, (1956); Orth R.W., Frequency-selective limiters and their application, IEEE Trans. Electromagn. Compat., EMC-10, 2, pp. 273-283, (1968); Adam J.D., Stitzer S.N., A magnetostatic wave signal-tonoise enhancer, Appl. Phys. Lett., 36, 6, pp. 485-487, (1980); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: Fast micromagnetic simulator for complex magnetic structures (invited), J. Appl. Phys., 109, 7, (2011); Oti J.O., SimulMag version 1.0, micromagnetic simulation software, user's manual, Electromagn. Technol. Division, (1997); Donahue M.J., Porter D.G., OOMMF user's guide, version 1.0, Nat. Inst. Stand. Technol, (1999); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Jpn. J. Appl. Math., 2, 1, pp. 69-84, (1985); Bruckner F., Et al., Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations, J. Magn. Magn. Mater., 343, pp. 163-168, (2013); Yang B., Fredkin D.R., Dynamical micromagnetics by the finite element method, IEEE Trans. Magn., 34, 6, pp. 3842-3852, (1998); Couture S., Lomakin V., Electromagnetic-micromagnetic simulator for magnetization-eddy current dynamics in magnetic materials and devices, Proc. IEEE Int. Symp. Antennas Propag., pp. 1117-1118, (2017); Monk P.B., Vacus O., Accurate discretization of a non-linear micromagnetic problem, Comput. Methods Appl. Mech. Eng., 190, 40-41, pp. 5243-5269, (2001); Farahani A.V., Konrad A., FDTD calculation of cavity resonant frequencies in case of nonuniform internal magnetic field distribution, IEEE Trans. Magn., 43, 4, pp. 1517-1520, (2007); Pereda J.A., Vielva L.A., Solano M.A., Vegas A., Prieto A., FDTD analysis of magnetized ferrites: Application to the calculation of dispersion characteristics of ferrite-loaded waveguides, IEEE Trans. Microw. Theory Techn., 43, 2, pp. 350-357, (1995); Yee K.S., Numerical solution of initial boundary value problems involving Maxwell's equations in isotropic media, IEEE Trans. Antennas Propag., AP-14, 3, pp. 302-307, (1966); Taflove A., Hagness S.C., Computational Electrodynamics: The Finite-Difference Time-Domain Method, (2000); Zhen F., Chen Z., Zhang J., Toward the development of a three-dimensional unconditionally stable finite-difference time-domain method, IEEE Trans. Microw. Theory Techn., 48, 9, pp. 1550-1558, (2000); Namiki T., A new FDTD algorithm based on alternating-direction implicit method, IEEE Trans. Microw. Theory Techn., 47, 10, pp. 2003-2007, (1999); Staker S.W., Holloway C.L., Bhobe A.U., Piket-May M., Alternating-direction implicit (ADI) formulation of the finite-difference time-domain (FDTD) method: Algorithm and material dispersion implementation, IEEE Trans. Electromagn. Compat., 45, 2, pp. 156-166, (2003); Chung Y.-K., Sarkar T.K., Baek H.J., Salazar-Palma M., An unconditionally stable scheme for the finite-difference timedomain method, IEEE Trans. Microw. Theory Techn., 51, 3, pp. 697-704, (2003); Sun C., Trueman C.W., Unconditionally stable Crank-Nicolson scheme for solving two-dimensional Maxwell's equations, Electron. Lett., 39, 7, pp. 595-597, (2003); Tan E.L., Fundamental schemes for efficient unconditionally stable implicit finite-difference time-domain methods, IEEE Trans. Antennas Propag., 56, 1, pp. 170-177, (2008); Gaffar M., Jiao D., An explicit and unconditionally stable FDTD method for electromagnetic analysis, IEEE Trans. Microw. Theory Techn., 62, 11, pp. 2538-2550, (2014); Tiwari S., Et al., Ferromagnetic resonance in bulk-acoustic wave multiferroic devices, Proc. Solid State Sens., Actuators, Microsyst. Workshop, pp. 420-423, (2016); Engquist B., Majda A., Absorbing boundary conditions for numerical simulation of waves, Proc. Nat. Acad. Sci. USA, 74, pp. 1765-1766, (1977); Roy R., Kailath T., Esprit-estimation of signal parameters via rotational invariance techniques, IEEE Trans. Acoust., Speech, Signal Process., 37, 7, pp. 984-995, (1989); Wang Y., Ling H., Multimode parameter extraction for multiconductor transmission lines via single-pass FDTD and signal-processing techniques, IEEE Trans. Microw. Theory Techn., 46, 1, pp. 89-96, (1998); Bernardi P., Valdoni F., Fundamentals of a new class of magnetically tunable waveguide filters, IEEE Trans. Magn., MAG-2, 3, pp. 264-268, (1966); Uher J., Arndt F., Bornemann J., Field theory design of ferriteloaded waveguide nonreciprocal phase shifters with multisection ferrite or dielectric slab impedance transformers, IEEE Trans. Microw. Theory Techn., MTT-35, 6, pp. 552-560, (1987); Bekker V., Seemann K., Leiste H., A new strip line broad-band measurement evaluation for determining the complex permeability of thin ferromagnetic films, J. Magn. Magn. Mater., 270, 3, pp. 327-332, (2004); Gu W., Xu Q., Wang Y.E., Two dimensional (2D) complex permeability characterization of thin film ferromagnetic material, Proc. IEEE Conf. Antennas Meas. Appl., pp. 1-4, (2016); (2016); Yousefi T., Sebastian T., Diaz R.E., Why the magnetic loss tangent is not a relevant constraint for permeable conformal antennas, IEEE Trans. Antennas Propag., 64, 7, pp. 2784-2796, (2016); Dong Y., Itoh T., Metamaterial-based antennas, Proc. IEEE, 100, 7, pp. 2271-2285, (2012); Yao Z., Wang Y.E., 3D ADI-FDTD modeling of platform reduction with thin film ferromagnetic material, Proc. IEEE Int. Symp. Antennas Propag., pp. 2019-2020, (2016); Balanis C.A., Advanced Engineering Electromagnetics, (2012); Berenger J.-P., A perfectly matched layer for the absorption of electromagnetic waves, J. Comput. Phys., 114, 2, pp. 185-200, (1994); Varadarajan V., Mittra R., Finite-difference time-domain (FDTD) analysis using distributed computing, IEEE Microw. Guided Wave Lett., 4, 5, pp. 144-145, (1994); Yao Z., Wang Y.E., 3D unconditionally stable FDTD modeling of micromagnetics and electrodynamics, Proc. IEEE Int. Microw. Symp., pp. 12-15, (2017)","Y.E. Wang; Electrical Engineering Department, University of California at Los Angeles, Los Angeles, 90024, United States; email: ywang@ee.ucla.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189480","","IETMA","","English","IEEE Trans. Microwave Theory Tech.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85046497570" +"Tanaka H.; Nakamura K.; Ichinokura O.","Tanaka, H. (55624472145); Nakamura, K. (55516112700); Ichinokura, O. (7003759274)","55624472145; 55516112700; 7003759274","Accuracy Improvement of Magnetic Hysteresis Calculated by LLG Equation","2017","Journal of Physics: Conference Series","903","1","012048","","","","12","10.1088/1742-6596/903/1/012048","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85034224676&doi=10.1088%2f1742-6596%2f903%2f1%2f012048&partnerID=40&md5=b51dea4febc385ea42d6bbefd0542890","Graduate School of Engineering, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan","Tanaka H., Graduate School of Engineering, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Ichinokura O., Graduate School of Engineering, Tohoku University, 6-6-05 Aoba Aramaki, Aoba-ku, Sendai, 980-8579, Japan","Quantitative estimation of iron loss including magnetic hysteresis behavior is essential to the development of high-efficient electrical machines. A simplified micromagnetic model using Landau-Lifshitz-Gilbert (LLG) equation is one of the useful models for calculating the hysteresis behavior. However, further improvement of the calculation accuracy under magnetic saturation is required. This paper presents the accuracy improvement of the magnetic hysteresis calculated by the LLG equation. © 2016 Published under licence by IOP Publishing Ltd.","","Hysteresis; Magnetic hysteresis; Accuracy Improvement; Calculation accuracy; Electrical machine; High efficient; Hysteresis behavior; Landau-Lifshitz-Gilbert equations; Micromagnetic modeling; Quantitative estimation; Magnetism","","","","","Grant-in Aid for JSPS, (26-5193)","improved to express the shape of the hysteresis loop with high accuracy. It was demonstrated that the proposed method can improve the accuracy of the magnetic nonlinearity and hysteresis behavior. This work was supported by Grant-in Aid for JSPS Fellows (26-5193).","Oshima H., Uehara Y., Shimizu K., Inagaki K., Furuya A., Fujisaki J., Suzuki M., Kawano K., Mifune T., Matsuo T., Watanabe K., Igarashi H., J. Jpn. Soc. Powder Metallurgy, 61, S1, pp. S238-S241, (2014); Tanaka H., Nakamura K., Ichinokura O., J. Magn. Soc. Jpn, 39, 2, pp. 65-70, (2015)","","","Institute of Physics Publishing","EMA","8th Joint European Magnetic Symposia, JEMS 2016","21 August 2016 through 26 August 2016","Glasgow","131605","17426588","","","","English","J. Phys. Conf. Ser.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85034224676" +"Ahmad N.; Yu T.; Khan S.; Majid A.; Iqbal J.; Shah S.A.; Awan S.U.; Han X.F.","Ahmad, Naeem (58834327800); Yu, Tian (53165310300); Khan, Suleman (57007470400); Majid, Abdul (57193352948); Iqbal, Javed (58855629100); Shah, Saqlain A. (35194611100); Awan, S.U. (55513181400); Han, X.F. (56411340200)","58834327800; 53165310300; 57007470400; 57193352948; 58855629100; 35194611100; 55513181400; 56411340200","Ferromagnetic Relaxation and Magnetic Properties of Co40Fe40B20 Thin Films","2017","Journal of Superconductivity and Novel Magnetism","30","2","","469","473","4","1","10.1007/s10948-016-3730-9","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84986276760&doi=10.1007%2fs10948-016-3730-9&partnerID=40&md5=67dd04fc521d522e4bfae95da8982763","Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, 44000, Pakistan; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, China; College of Physical Science and Technology, Sichuan University, Chengdu, 610064, China; Department of Physics, University of Gujrat, Gujrat, Pakistan; Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan; Department of Physics, Forman Christian College (University), Lahore, Pakistan; Department of Physics, COMSATS Institute of Information Technology, Islamabad, 45320, Pakistan","Ahmad N., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, 44000, Pakistan, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, China; Yu T., College of Physical Science and Technology, Sichuan University, Chengdu, 610064, China; Khan S., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, 44000, Pakistan; Majid A., Department of Physics, University of Gujrat, Gujrat, Pakistan; Iqbal J., Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan; Shah S.A., Department of Physics, Forman Christian College (University), Lahore, Pakistan; Awan S.U., Department of Physics, COMSATS Institute of Information Technology, Islamabad, 45320, Pakistan; Han X.F., Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, 100190, China","The Co40Fe40B20 thin films with varying thickness using silicon dioxide (SiO2) as substrate were fabricated by magnetron sputtering system (ULVAC, Japan) with a base pressure P = 10−8 Torr to understand magnetodynamic interactions and structural properties. The samples were characterized using X-band ferromagnetic resonance experiments at room temperature. The XRD pattern shows that the thin film is amorphous and we got a strong peak (400) of substrate silicon dioxide (SiO2). The SEM result of Co40Fe40B20 thin film demonstrates that it has uniform and homogeneous morphology. It has been observed from ferromagnetic resonance (FMR) results that the thin film depicts anisotropic behavior and easy axis lies out of the plane. The dependence of the resonance fields on the angle between the normal of the film and out of plane dc magnetic field indicates the presence of uniaxial magnetic anisotropy associated with thickness of Co40Fe40B20 thin films. The inplane and out-of-plane angular dependences of the resonance field (HR) and line width (ΔHpp) of FMR spectra were measured and explained using the Landau–Lifshitz–Gilbert equation. The origin of magnetic damping has been discussed by considering spin–orbit, s–d interactions, and two magnonscattering mechanism. Some background molecular vibrations at wave number 2000 and 3800 cm−1 in three samples are also identified from FTIR, which further show that background molecular vibrations can be reduced by decreasing the size. This study will be helpful to understand spin transfer torque (STT) and the timescale for magnetization reversal in the spintronic devices © 2016, Springer Science+Business Media New York.","Ferromagnetic relaxation; Ferromagnetic thin films; LLG equatation","Amorphous films; Amorphous silicon; Anisotropy; Cobalt; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Fourier transform infrared spectroscopy; Magnetic anisotropy; Magnetism; Magnetization reversal; Molecular vibrations; Resonance; Silica; Silicon oxides; Substrates; Ferromagnetic relaxation; Ferromagnetic resonance (FMR); Ferromagnetic thin films; Homogeneous morphology; LLG equatation; Magnetic properties of co; Magnetron sputtering systems; Uniaxial magnetic anisotropy; Thin films","","","","","Higher Education Commision, Pakistan, HEC, (PMIPFP/HRD/HEC/2011/354); Higher Education Commision, Pakistan, HEC","Naeem Ahmad is thankful to Higher Education Commission of Pakistan for financial support (Grant No:PMIPFP/HRD/HEC/2011/354).","Ciureanu M., Elechtrocehimica Acta, 50, (2005); Malinowski G., Kuiper K.C., Lavrijsen R., Swagten H.J.M., Koopmans B., Magnetization dynamics and Gilbert damping in ultrathin Co48Fe32B20 films with out of plane anisotropy, Appl. Phys. Lett., 94, (2009); Bilzer C., Devolder T., Kim J.-V., Counil G., Chappert C., Cardoso S., Freitas P.P., Study of the dynamic magnetic properties of soft CoFeB film, J. Appl. Phys., 100, (2006); Boone C.T., Shaw J.M., Nembach H.T., Silva T.J., Spin-scattering rates in metallic thin films measured by ferromagnetic resonance damping enhanced by spin-pumping, J. Appl. Phys., 117, (2015); Ikeda S., Miura K., Yamamoto H., Mizunuma K., Gan H.D., Endo M., Kanai S., Hayakawa J., Matsukura F., Ohno H., A perpendicular-anisotropy_CoFeB-MgO magnetic tunnel junction, Nat. Mater., 9, pp. 721-724, (2010); Mangin S., Ravelosona D., Katine J.A., Carrey M.J., Terris B.D., Fullerton E.E., Current-induced magnetization reversal in nanopillars with perpendicular anisotropy, Nature Mater., 5, (2006); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Cyrille M.-C., Redon O., Dieny B., Nature Mater., 6, (2007); Boulle O., Cros V., Grollier J., Pereira L.G., Deranlot C., Petroff F., Faini G., Barnas J., Fert A., Nat. Phys., 3, (2007); Thomas L., Parkin S.S.P., Handbook of Magnetism and Advanced Magnetic Materials 2, pp. 942-982, (2007); Chen S., Tang M., Zhang Z., Ma B., Lou S.T., Interfacial effect on the ferromagnetic damping of CoFeB thin films with different under-layers, Appl. Phys. Lett., 103, (2013); Sun Y., Song Y.-Y., Chang H., Kabatek M., Jantz M., Growth and ferromagnetic resonance properties of nanometer-thick yttrium iron garnet films, Appl. Phys. Lett., 94, (2009); Paluskar P.V., Lavrijsen R., Sicot M., Kohlhepp J.T., Swagten H.J.M., Koopmans B., Correlation between magnetism and spin-dependent transport in CoFeB alloys, Phys, Rev. Lett., 102, (2009); Ebels U., Duvail J.-L., Wigen P.E., Piraux L., Buda L.D., Ounadjela K., Phys. Rev, B, 64, (2001); Platow W., Anisimov A.N., Dunifer G.L., Farle M., Baberschke K., Correlations between ferromagnetic resonance linewidths and sample quality in the study of metallic ultrathin films, Phys. Rev. B, 58, (1998); Stuart B., Infrared Spectroscopy: Fundamentals and Applications, (2004); Molecular symmetry and group theory (Chichester, UK), (2001); Smith B.C., Fundamentals of Fourier Transform Infrared Spectroscopy, (2011)","N. Ahmad; Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, 44000, Pakistan; email: naeem.ahmad@iiu.edu.pk","","Springer New York LLC","","","","","","15571939","","","","English","J Supercond Novel Magn","Article","Final","","Scopus","2-s2.0-84986276760" +"Couture S.; Lomakin V.","Couture, Simon (36536819800); Lomakin, Vitaliy (35570326300)","36536819800; 35570326300","Electromagnetic-micromagnetic simulator for magnetization-eddy current dynamics in magnetic materials and devices","2017","2017 IEEE Antennas and Propagation Society International Symposium, Proceedings","2017-January","","","1117","1118","1","3","10.1109/APUSNCURSINRSM.2017.8072601","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85042236511&doi=10.1109%2fAPUSNCURSINRSM.2017.8072601&partnerID=40&md5=6cd2cc79424c161b439441df6f6a3a7b","Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA, United States","Couture S., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA, United States; Lomakin V., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, CA, United States","A coupled Landau-Lifshitz-Gilbert (LLG)-Maxwell equations solver is presented. The solver uses the quasistatic approximation to the Maxwell equations and can be used to study the effect of eddy currents dynamics on the electromagnetic fields solution and on the magnetization dynamics in magnetic systems. The proposed approach uses two parallel solvers, one for the LLG equation, one for the Maxwell equations, and integrates in time using an error controlled Newton method. Numerical results are validated by comparing with a known analytical solution. © 2017 IEEE.","","Dynamics; Electromagnetic fields; Electromagnetic simulation; Magnetic materials; Magnetization; Maxwell equations; Newton-Raphson method; Landau-Lifshitz-Gilbert; LLG equation; Magnetic system; Magnetization dynamics; Micromagnetic simulators; Numerical results; Parallel solver; Quasistatic approximations; Eddy currents","","","","","","","Torres L., Martinez E., Lopez-Diaz L., Alejos O., About the inclusion of eddy currents in micromagnetic computations, Physica B, 343, (2004); Hrkac G., Kirschner M., Dorfbauer F., Suess D., Ertl O., Fidler J., Schrefl T., Three-dimensional micromagnetic finite element simulations including eddy currents, J. Appl. Phys., 97, (2005); Sayed S.B., Ulku H.A., Bagci H., Transient analysis of scattering from ferromagnetic objects using landau-lifshitz-gilbert and volume integral equations, APS International Symposium, (2016); Knoepfel H.E., Magnetic Fields, (2000); Haus H.A., Melcher J.R., Electromagnetic Fields and Energy, (1989)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (APS); The Institute of Electrical and Electronics Engineers (IEEE)","2017 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2017","9 July 2017 through 14 July 2017","San Diego","131256","","978-153863284-0","","","English","IEEE Antennas Propag. Soc. Int. Symp., Proc.","Conference paper","Final","","Scopus","2-s2.0-85042236511" +"Chen J.; Jalil M.B.A.; Tan S.G.; Siu Z.B.; Peng Y.Z.","Chen, Ji (56687961100); Jalil, Mansoor B. A. (7006821429); Tan, Seng Ghee (8571745900); Siu, Zhuo Bin (36009543000); Peng, Ying Zi (7403419324)","56687961100; 7006821429; 8571745900; 36009543000; 7403419324","Spin torques due to various linear spin-orbit coupling in semiconductor and graphene systems in the adiabatic limit","2017","EPL","118","2","27002","","","","2","10.1209/0295-5075/118/27002","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85021972323&doi=10.1209%2f0295-5075%2f118%2f27002&partnerID=40&md5=01308397a41b2077f17b4bc3557125bc","Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore; Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore; Data Storage Institute, A STAR (Agency for Science, Technology and Research), Engineering Drive 1, Singapore, 117608, Singapore; Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Center for Integrated Spintronic Devices, Hangzhou Dianzi University, Hangzhou, 310018, China","Chen J., Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Jalil M.B.A., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore, Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore; Tan S.G., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore, Data Storage Institute, A STAR (Agency for Science, Technology and Research), Engineering Drive 1, Singapore, 117608, Singapore; Siu Z.B., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore, Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore; Peng Y.Z., Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China, Center for Integrated Spintronic Devices, Hangzhou Dianzi University, Hangzhou, 310018, China","We use the gauge formalism to investigate the current-induced spin dynamics in ferromagnetic media with spatially varying local magnetization, which is coupled to various material systems exhibiting linear spin-orbit coupling (SOC) effects, such as semiconductor and graphene materials. We perform a gauge transformation to the system, and obtain a gauge field (vector potential) in the adiabatic limit, i.e., strong coupling between the spin of the conduction electrons to the magnetization. The gauge field interacts with the applied current, resulting in a current-driven effective magnetic field and the corresponding spin torque acting on the magnetization of the FM media. We find that the current-driven spin orbit torque in various linear SOC systems and graphene systems can be described by a unified way. We propose a generalized Landau-Lifshitz-Gilbert (LLG) equation which includes this effective field term. © CopyrightEPLA, 2017.","","","","","","","","","Slonczewski J., J. Magn. & Magn. Mater., 159, 1-2, (1996); Stiles M.D., Miltat J., Top. Appl. Phys., 101, (2006); Ralph D.C., Stiles M.D., J. Magn. & Magn. Mater., 320, 7, (2008); Sun J.Z., Ralph D.C., J. Magn. & Magn. Mater., 320, 7, (2008); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, 14, (2000); Rippard W.H., Pufall M.R.S., Kaka S., Russek S.E., Silva T.J., Phys. Rev. Lett., 92, 2, (2004); Rezende S.M., De Aguiar F.M., Azevedo A., Phys. Rev. Lett., 94, 3, (2005); Gmitra M., Barnas J., Phys. Rev. Lett., 96, 20, (2006); Tsoi M., Et al., Phys. Rev. Lett., 80, 19, (1998); Katine J.A., Fullerton E.E., J. Magn. & Magn. Mater., 320, 7, (2008); Pareek T.P., Phys. Rev. B, 75, 11, (2007); Nunez A.S., MacDonald A.H., Solid State Commun., 139, 1, (2006); Tan S.G., Jalil M.B.A., Liu X.J., (2007); Tan S.G., Jalil M.B.A., Liu X.J., Ann. Phys., 326, 2, (2011); Machon A., Zhang S., Phys. Rev. B, 78, (2008); Machon A., Zhang S., Phys. Rev. B, 79, 9, (2009); Obata K., Tatara G., Phys. Rev. B, 77, 21, (2008); Miron L.M., Gaudin G., Auffret S., Rodmacq B., Schuhl A., Pizzini S., Vogel J., Gambardella P., Nat. Mater., 9, (2010); Miron I.H., Gaudin G.K.G., Zermatten P.J., Costache M.V., Auffret S., Bandiera S., Rodmacq B., Schuhl A., Gambardella P., Nat. 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Rev., 100, 2, (1955); Dresselhaus P.D., Papavassiliou C.M.A., Wheeler R.G., Sacks R.N., Phys. Rev. Lett., 68, 1, (1992); Schliemann J., Int. J. Mod. Phys. B, 20, 9, (2006); Bastard G., Ferreira R., Surf. Sci., 267, 1-3, (1992); D'Yakonov M.I., Kachorovskii V.Y., Sov. Phys. Semicond., 20, (1986); Fabian J., Matos-Abiague A., Schuh D., Wegscheider Fabian W.J., Weiss D., Phys. Rev. Lett., 99, 5, (2007); Bernevig B.A., Orenstein J., Zhang S.C., Phys. Rev. Lett., 97, 23, (2006); Pikus G.E., Titkov A.N., Optical Orientation, (1984); Haney P.M., Stiles M.D., Phys. Rev. Lett., 105, 12, (2010); Dedkov Y.S., Fonin M., Rudiger U., Laubschat C., Phys. Rev. Lett., 100, 10, (2008); Varykhalov A., Sanchez-Barriga J., Shikin A.M., Biswas C., Vescovo E., Rybkin A., Marchenoko D., Rader O., Phys. Rev. Lett., 101, 15, (2008); Li H., Wang X., Manchon A., Phys. Rev. B, 93, 3, (2016); Dyrdal A., Barnas J., Phys. Rev. B, 92, 16, (2015); Chen J., Jalil M.B.A., Tan S.G., AIP Adv., 3, 6, (2013); Malshukov A.G., Tang C.S., Chu C.S., Chao K.A., Phys. Rev. Lett., 95, 10, (2005); Bernevig B.A., Zhang S.C., Phys. Rev. B, 72, 11, (2005)","J. Chen; Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; email: muze7777@hdu.edu.cn","","Institute of Physics Publishing","","","","","","02955075","","","","English","EPL","Article","Final","","Scopus","2-s2.0-85021972323" +"Li H.; Zhang X.-H.","Li, Hang (55735858900); Zhang, Xin-Hui (10144484900)","55735858900; 10144484900","Analysis of fitting methods for laser-triggered ultrafast magnetization dynamics in diluted magnetic semiocnductor (Ga, Mn)As film","2015","Wuli Xuebao/Acta Physica Sinica","64","17","177503","","","7","0","10.7498/aps.64.177503","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84941794119&doi=10.7498%2faps.64.177503&partnerID=40&md5=0796b6ebf8d9616c60038c1b72491130","State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","Li H., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; Zhang X.-H., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","Laser-triggered magnetization dynamics for diluted magnetic semiconductor (Ga, Mn)As has drawn great attention in recent years, aiming at studying the ultrafast manipulation of collective spin excitations towards spintronic information processing. In this work, different fitting methods for time-resolved magneto-optical Kerr effect (TR-MOKE) study of the laser-triggered magnetization dynamics in a diluted magnetic semiconductor (Ga, Mn)As are analyzed and compared. It is known that the exponentially damped cosine harmonic function and the numerical simulation based on Landau- Lifshitz-Gilbert (LLG) equation are usually applied to fit the laser-induced magnetization dynamics from TR-MOKE measurements. Under the specified experimental conditions, it is sometimes hard to fit the TR-MOKE response well with single-mode uniform precession by using the exponentially damped cosine harmonic function. Although the fitting with multiple precession frequencies may usually show much better fitting results, the numerical simulation based on LLG equation reveals that the multi-frequency precessional modes are caused by the superposition of three-dimensional trajectories of magnetization precession with different contributions from the in-plane and out-of-plane magneto-optical response in (Ga, Mn)As. Thus, the multi-frequency precessional modes obtained by adopting the fitting method with exponentially damped cosine harmonic function could be the fake ones. Meanwhile, it is important to note that though the LLG equation can be used to fit the macroscopic magnetization precession well with single frequency, the contribution of pulse-like background response from photo-generated polarized carriers at the above-bandgap excitation is strongly superimposed on the magnetization precession response, and the pulse-like background response cannot be described by LLG equation. Thus one should be cautious of applying LLG equation only to fit the entire TR-MOKE signal, especially when the excitation energy is above the band gap of (Ga, Mn)As. One may combine both fitting methods, namely, fitting with the exponentially damped cosine harmonic function and the LLG simulation by considering both the in-plane and out-of-plane magneto-optical response of (Ga, Mn)As film in order to properly fit the laser-triggered magnetization dynamic response from TR-MOKE measurements. The proper handling of fitting methods helps to extract the dynamic magnetic parameters correctly and to further understand the physical mechanisms for triggering the ultrafast manipulation of collective spin dynamics. This is fundamentally important for developing novel spintronics based on diluted magnetic semiconductor (Ga, Mn)As. © 2015 Chinese Physical Society.","(Ga; Magnetization dynamics; Mn)As; Time-resolved magneto-optical Kerr effect (TRMOKE)","Diluted magnetic semiconductors; Dynamics; Energy gap; Harmonic analysis; Harmonic functions; Magnetization; Numerical models; Semiconductor lasers; Spin dynamics; Spintronics; Ultrafast phenomena; Experimental conditions; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetization precession; Three dimensional trajectories; Time-resolved magneto-optical Kerr effects; Ultrafast magnetization dynamics; Ultrafast manipulation; Optical Kerr effect","","","","","National Natural Science Foundation of China, (10974195)","","Dietl T., Awschalom D.D., Kaminska M., Ohno H., Spintronics, pp. 90-128, (2008); Dietl T., Nat. Mater., 9, (2010); Kirilyuk A., Kimel A.V., Rasing T., Rev. Mod. 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Lett., 100, (2012); Tesarova N., Subrt J., Maly P., Nemec P., Ellis C.T., Mukherjee A., Cerne J., Rev. Sci. Instrum., 83, (2012); Rozkotova E., Nemec P., Sprinzl D., Horodyska P., Trojanek F., Maly P., Novak V., Olejnik K., Cukr M., Jungwirth T., IEEE Tran. Magn., 44, (2008); Rozkotova E., Nemec P., Horodyska P., Sprinzl D., Trojanek F., Maly P., Novak V., Olejnik K., Cukr M., Jungwirth T., Appl. Phys. Lett., 92, (2008); De Boer T., Gamouras A., March S., Novak V., Hall K.C., Phys. Rev. B, 85, (2012)","X.-H. Zhang; State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; email: xinhuiz@semi.ac.cn","","Institute of Physics, Chinese Academy of Sciences","","","","","","10003290","","WLHPA","","Chinese","Wuli Xuebao","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-84941794119" +"Daqiq R.; Ghobadi N.","Daqiq, Reza (35114843800); Ghobadi, Nader (25651468900)","35114843800; 25651468900","Effect of Tunnel Barrier Thickness on Spin-Transfer Torque, Charge Current, and Shot Noise in a Magnetic Tunnel Junction Nanostructure","2016","Journal of Superconductivity and Novel Magnetism","29","6","","1675","1680","5","2","10.1007/s10948-016-3455-9","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84966415418&doi=10.1007%2fs10948-016-3455-9&partnerID=40&md5=edeb304ff9b22ce494a1363f814791a2","Department of Physics, Malayer University, Malayer, Iran","Daqiq R., Department of Physics, Malayer University, Malayer, Iran; Ghobadi N., Department of Physics, Malayer University, Malayer, Iran","We study tunnel barrier thickness effects on spin-transfer torque (STT) components, charge current, and thermal-shot noise power in an MgO-based magnetic tunnel junction (MTJ) nanostructure using non-equilibrium Green’s function (NEGF) formalism. Also, the bias dependence of the in-plane and perpendicular torkances is investigated. From the NEGF calculations, we find that the STT components are independent of barrier thickness. Magnetization dynamics is described by the Landau-Lifshits-Gilbert (LLG) equation. The charge current decreases for increasing barrier thicknesses. The thermal-shot noise shows linear behavior with increasing of bias voltage for different barrier thicknesses. © 2016, Springer Science+Business Media New York.","Charge current; MTJ nanostructure; Spin-transfer torque; Thermal-shot noise","Magnetic devices; Nanostructures; Tunnel junctions; Barrier thickness; Bias dependence; Charge current; Linear behavior; Magnetic tunnel junction; Magnetization dynamics; Non equilibrium; Spin transfer torque; Shot noise","","","","","","","Yuasa S., Nagahama T., Fukushima A., Suzuki Y., Ando K., Giant room temperature magneto-resistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions, Nat. Mater, 3, (2004); Parkin S.S.P., Kaiser C., Panchula A., Rice P.M., Hughes B., Samant M., Yang S.H., Giant tunneling magneto-resistance at room temperature with MgO(100) tunnel barriers, Nat. Mater, 3, (2004); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, pp. L1-L7, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, (1996); Petit S., Baraduc C., Thirion C., Ebels U., Liu Y., Li M., Wang P., Dieny B., Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions, Phys. Rev. Lett, 98, (2007); Chaves R.C., Freitas P.P., Ocker B., Maass W., Low frequency picotesla field detection using hybrid MgO-based tunnel sensors, Appl. Phys. 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Phys, 4, (2008); Oh S.-C., Park S.-Y., Manchon A., Chshiev M., Han J.-H., Lee H.-W., Lee J.-E., Nam K.-T., Jo Y., Kong Y.-C., Dieny B., Lee K.-J., Bias-voltage dependence of perpendicular spin-transfer torque in asymmetric MgO-based magnetic tunnel junctions, Nat. Phys, 5, (2009); Theodonis I., Kioussis N., Kalitsov A., Chshiev M., Butler W.H., Vedyayev A., Spin-polarized current-induced torque in magnetic tunnel junctions, J. Appl. Phys, 99, (2006); Theodonis I., Kioussis N., Kalitsov A., Chshiev M., Butler W.H., Anomalous bias dependence of spin torque in magnetic tunnel junctions, Phys. Rev. Lett, 97, (2006); Kalitsov A., Chshiev M., Theodonis I., Kioussis N., Butler W.H., Spin-transfer torque in magnetic tunnel junctions, Phys. Rev. B, 79, (2009); Tang Y.-H., Kioussis N., Kalitsov A., Butler W.H., Car R., Influence of asymmetry on bias behavior of spin torque, Phys. Rev. B, 81, (2010); Tang Y.-H., Kioussis N., Kalitsov A., Butler W.H., Car R., Controlling the nonequilibrium interlayer exchange coupling in asymmetric magnetic tunnel junctions, Phys. Rev. Lett, 103, (2009); Kalitsov A., Silvestre W., Chshiev M., Velev P., Spin torque in magnetic tunnel junctions with asymmetric barriers, Phys. Rev. B, 88, (2013); Slonczewski J.C., Currents, torques, and polarization factors in magnetic tunnel junctions, Phys. Rev. B, 71, (2005); Datta S., Nanoscale device modeling: the Green’s function method, Superlattice. Microst, 28, (2000); Datta S., Quantum transport: Atom to Transistor, (2005); Datta D., Behin-Aein B., Salahuddin S., Datta S., Voltage asymmetry of spin transfer torques, IEEE. Trans. Nano, 11, (2012); Lei Z.Q., Li G.J., Egelhoff W.F., Lai P.T., Pong P.W.T., Review of noise sources in magnetic tunnel junction sensors, IEEE. Trans. Magn, 47, (2011); Wang C., Cui Y.-T., Sun J.Z., Katine J.A., Buhrman R.A., Ralph D.C., Bias and angular dependence of spin-transfer torque in magnetic tunnel junctions, Phys. Rev. B, 79, (2009); Wang C., Cui Y.T., Katine J., Buhrman R., Ralph D.C., Time-resolved measurement of spin-transfer-driven ferromagnetic resonance and spin torque in magnetic tunnel junctions, Nat. Phys, 7, (2011); Heiliger C., Stiles M.D., Ab Initio Studies of the spin-transfer torque in magnetic tunnel junctions, Phys. Rev. Lett, 100, (2008); Jia X., Xia K., Ke Y., Guo H., Nonlinear bias dependence of spin-transfer torque from atomic first principles, Phys. Rev. B, 84, (2011); Xiao J., Bauer G.E.W., Brataas A., Spin transfer torque in magnetic tunnel junctions: scattering theory, Phys. Rev. B, 77, (2008); Ralph D.C., Stiles M.D., Spin transfer torques, J. Magn. Magn. Mater, 320, (2008); Chanthbouala A., Matsumoto R., Grollier J., Cros V., Anane A., Fert A., Khvalkovskiy A.V., Zvezdin K.A., Nishimura K., Nagamine Y., Maehara H., Tsunekawa K., Fukushima A., Yuasa S., Vertical-current-induced domain-wall motion in MgO-based magnetic tunnel junctions with low current densities, Nat. Phys, 7, (2011); Matsumoto R., Chanthbouala A., Grollier J., Cros V., Fert A., Nishimura K., Nagamine Y., Maehara H., Tsunekawa K., Fukushima A., Yuasa S., Spin-torque diode measurements of MgO-based magnetic tunnel junctions with asymmetric electrodes, Appl. Phys. Express, 4, (2011); Slonczewski J.C., Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier, Phys. Rev. B, 39, (1989); Manchon A., Zhang S., Lee K.-J., Signatures of asymmetric and inelastic tunneling on the spin torque bias dependence, Phys. Rev. B, 82, (2010); Tang Y.-H., Kioussis N., Crucial role of interfacial alloying on spin-transfer torque in magnetic tunnel junctions, Phys. Rev. B, 85, (2012); Zeng Z.M., Et al., Effect of resistance-area product on spin-transfer switching in MgO-based magnetic tunnel junction memory cells, Appl. Phys. Lett, 98, (2011); Brataas A., Kent A.D., Ohno H., Current-induced torques in magnetic materials, Nat. Mater, 11, (2012); Sun J.Z., Spin-current interaction with a monodomain magnetic body: a model study, Phys. Rev. B, 62, (2000)","N. Ghobadi; Department of Physics, Malayer University, Malayer, Iran; email: nader.ghobadi@gmail.com","","Springer New York LLC","","","","","","15571939","","","","English","J Supercond Novel Magn","Article","Final","","Scopus","2-s2.0-84966415418" +"Exl L.; Mauser N.J.; Schrefl T.; Suess D.","Exl, Lukas (53863546300); Mauser, Norbert J. (7004158395); Schrefl, Thomas (7005780657); Suess, Dieter (7004076065)","53863546300; 7004158395; 7005780657; 7004076065","The extrapolated explicit midpoint scheme for variable order and step size controlled integration of the Landau–Lifschitz–Gilbert equation","2017","Journal of Computational Physics","346","","","14","24","10","5","10.1016/j.jcp.2017.06.005","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85020850796&doi=10.1016%2fj.jcp.2017.06.005&partnerID=40&md5=9f35f759ddac4d0c44a8712a57f8993f","Fak. Mathematik, Univ. Wien, Vienna, 1090, Austria; Physics of Functional Materials, Univ. Wien, Vienna, 1090, Austria; Wolfgang Pauli Institute c/o Fak. Mathematik, Univ. Wien, Vienna, 1090, Austria; Center of Integrated Sensor Systems, Danube Univ. Krems, Wr. Neustadt, 2700, Austria; Doppler Laboratory “Advanced Magnetic Sensing and Materials”, Univ. Wien, Vienna, 1090, Austria","Exl L., Fak. Mathematik, Univ. Wien, Vienna, 1090, Austria, Physics of Functional Materials, Univ. Wien, Vienna, 1090, Austria; Mauser N.J., Wolfgang Pauli Institute c/o Fak. Mathematik, Univ. Wien, Vienna, 1090, Austria; Schrefl T., Center of Integrated Sensor Systems, Danube Univ. Krems, Wr. Neustadt, 2700, Austria; Suess D., Doppler Laboratory “Advanced Magnetic Sensing and Materials”, Univ. Wien, Vienna, 1090, Austria","A practical and efficient scheme for the higher order integration of the Landau–Lifschitz–Gilbert (LLG) equation is presented. The method is based on extrapolation of the two-step explicit midpoint rule and incorporates adaptive time step and order selection. We make use of a piecewise time-linear stray field approximation to reduce the necessary work per time step. The approximation to the interpolated operator is embedded into the extrapolation process to keep in step with the hierarchic order structure of the scheme. We verify the approach by means of numerical experiments on a standardized NIST problem and compare with a higher order embedded Runge–Kutta formula. The efficiency of the presented approach increases when the stray field computation takes a larger portion of the costs for the effective field evaluation. © 2017 Elsevier Inc.","Explicit midpoint scheme; Extrapolation method; Landau–Lifschitz–Gilbert equation; Micromagnetics; Variable order method","Integral equations; Integration; Piecewise linear techniques; Runge Kutta methods; Explicit midpoint scheme; Extrapolation methods; High-order; Higher-order; Landau–lifschitz–gilbert equation; Micromagnetics; Midpoint scheme; Stray field; Variable order method; Variables ordering; Extrapolation","","","","","Vienna Science and Technology Fund, WWTF, (MA16-066); Vienna Science and Technology Fund, WWTF; Austrian Science Fund, FWF, (W1245); Austrian Science Fund, FWF","Financial support by the Austrian Science Foundation (FWF) under grant No. F41 (SFB “VICOM”), grant No. F65 (SFB “Complexity in PDEs”) and grant No. W1245 (DK “Nonlinear PDEs”) and the Wiener Wissenschafts- und TechnologieFonds (WWTF) project No. MA16-066 (“SEQUEX”). The computational results have been achieved using the Vienna Scientific Cluster (VSC).","Brown W.F., Micromagnetics, Interscience Tracts on Physics and Astronomy, 18, (1963); Suess D., Vogler C., Abert C., Bruckner F., Windl R., Breth L., Fidler J., Fundamental limits in heat-assisted magnetic recording and methods to overcome it with exchange spring structures, J. Appl. Phys., 117, 16, (2015); Kovacs A., Oezelt H., Schabes M., Schrefl T., Numerical optimization of writer and media for bit patterned magnetic recording, J. Appl. Phys., 120, 1, (2016); Makarov A., Sverdlov V., Osintsev D., Selberherr S., Fast switching in magnetic tunnel junctions with two pinned layers: micromagnetic modeling, IEEE Trans. Magn., 48, 4, pp. 1289-1292, (2012); Sepehri-Amin H., Ohkubo T., Nagashima S., Yano M., Shoji T., Kato A., Schrefl T., Hono K., High-coercivity ultrafine-grained anisotropic Nd–Fe–B magnets processed by hot deformation and the Nd–Cu grain boundary diffusion process, Acta Mater., 61, 17, pp. 6622-6634, (2013); Bance S., Oezelt H., Schrefl T., Winklhofer M., Hrkac G., Zimanyi G., Gutfleisch O., Evans R., Chantrell R., Shoji T., Yano M., Sakuma N., Kato A., Manabe A., High energy product in Battenberg structured magnets, Appl. Phys. Lett., 105, 19, (2014); Kronmuller H., General Micromagnetic Theory, (2007); d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau–Lifshitz–Gilbert equation based on the mid-point rule, J. Comput. Phys., 209, 2, pp. 730-753, (2005); Suess D., Tsiantos V., Schrefl T., Fidler J., Scholz W., Forster H., Dittrich R., Miles J., Time resolved micromagnetics using a preconditioned time integration method, J. Magn. Magn. Mater., 248, 2, pp. 298-311, (2002); Donahue M.J., Porter D.G.; Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau–Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci., 16, 2, pp. 299-316, (2006); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau–Lifshitz–Gilbert equation, SIAM J. Numer. Anal., 44, 4, pp. 1405-1419, (2006); Kritsikis E., Vaysset A., Buda-Prejbeanu L.D., Alouges F., Toussaint J.-C., Beyond first-order finite element schemes in micromagnetics, J. Comput. Phys., 256, pp. 357-366, (2014); Abert C., Exl L., Selke G., Drews A., Schrefl T., Numerical methods for the stray-field calculation: a comparison of recently developed algorithms, J. Magn. Magn. Mater., 326, pp. 176-185, (2013); Exl L., Bance S., Reichel F., Schrefl T., Stimming H.-P., Mauser N.J., LaBonte's method revisited: an effective steepest descent method for micromagnetic energy minimization, J. Appl. Phys., 115, 17, (2014); Fischbacher J., Kovacs A., Oezelt H., Schrefl T., Exl L., Fidler J., Suess D., Sakuma N., Yano M., Kato A., Shoji T., Manabe A., Conjugate gradient methods in micromagnetics; Garcia-Cervera C.J., Numerical micromagnetics: a review, Bol. Soc. Esp. Mat. Apl., 39, 103-135, (2007); Hairer E., Norsett S.P., Wanner G., Solving Ordinary Differential Equations, I: Nonstiff Problems, Springer Series in Computational Mathematics, (1987); Tsiantos V.D., Suess D., Schrefl T., Fidler J., Stiffness analysis for the micromagnetic standard problem No. 4, J. Appl. Phys., 89, 11, pp. 7600-7602, (2001); Gragg W.B., On extrapolation algorithms for ordinary initial value problems, J. Soc. Ind. Appl. Math., Ser. B Numer. Anal., 2, 3, pp. 384-403, (1965); Stetter H.J., Symmetric two-step algorithms for ordinary differential equations, Computing, 5, 3, pp. 267-280, (1970); Deuflhard P., Recent progress in extrapolation methods for ordinary differential equations, SIAM Rev., 27, 4, pp. 505-535, (1985); Bulirsch R., Stoer J., Numerical treatment of ordinary differential equations by extrapolation methods, Numer. Math., 8, 1, pp. 1-13, (1966); Hairer E., Norsett S.P., Wanner G., Solving Ordinary Differential Equations, I: Nonstiff Problems, Springer Series in Computational Mathematics, (1993); μMAG micromagnetic modeling activity group; Aharoni A., Introduction to the Theory of Ferromagnetism, vol. 109, (2000); Exl L., Auzinger W., Bance S., Gusenbauer M., Reichel F., Schrefl T., Fast stray field computation on tensor grids, J. Comput. Phys., 231, 7, pp. 2840-2850, (2012); Exl L., Abert C., Mauser N.J., Schrefl T., Stimming H.P., Suess D., FFT-based Kronecker product approximation to micromagnetic long-range interactions, Math. Models Methods Appl. Sci., 24, 9, pp. 1877-1901, (2014); Miltat J.E., Donahue M.J., Numerical micromagnetics: finite difference methods, Handbook of Magnetism and Advanced Magnetic Materials, (2007)","L. Exl; Fak. Mathematik, Univ. Wien, Vienna, 1090, Austria; email: lukas.exl@univie.ac.at","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85020850796" +"Kudo K.","Kudo, Kazue (9841682600)","9841682600","Effects of Landau-Lifshitz-Gilbert damping on domain growth","2016","Physical Review E","94","6","062215","","","","3","10.1103/PhysRevE.94.062215","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85007416016&doi=10.1103%2fPhysRevE.94.062215&partnerID=40&md5=19b6a778657090f68798a4e6f97c7c36","Department of Computer Science, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo, 112-8610, Japan","Kudo K., Department of Computer Science, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo, 112-8610, Japan","Domain patterns are simulated by the Landau-Lifshitz-Gilbert (LLG) equation with an easy-axis anisotropy. If the Gilbert damping is removed from the LLG equation, it merely describes the precession of magnetization with a ferromagnetic interaction. However, even without the damping, domains that look similar to those of scalar fields are formed, and they grow with time. It is demonstrated that the damping has no significant effects on domain growth laws and large-scale domain structure. In contrast, small-scale domain structure is affected by the damping. The difference in small-scale structure arises from energy dissipation due to the damping. © 2016 American Physical Society.","","Energy dissipation; Domain growth; Domain pattern; Easy-axis anisotropy; Ferro-magnetic interactions; Gilbert damping; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Small-scale structures; Damping","","","","","","","Bray A., Adv. Phys., 43, (1994); Lifshitz I.M., Slyozov V.V., J. Phys. Chem. Solids, 19, (1961); Wagner C., Z. Elektrochem., 65, (1961); Ohta T., Jasnow D., Kawasaki K., Phys. Rev. Lett., 49, (1982); Huse D.A., Phys. Rev. B, 34, (1986); Bray A.J., Phys. Rev. Lett., 62, (1989); Bray A.J., Phys. Rev. B, 41, (1990); Bray A.J., Rutenberg A.D., Phys. Rev. e, 49, (1994); Kudo K., Kawaguchi Y., Phys. Rev. A, 88, (2013); Hofmann J., Natu S.S., Das Sarma S., Phys. Rev. Lett., 113, (2014); Williamson L.A., Blakie P.B., Phys. Rev. Lett., 116, (2016); Furukawa H., Phys. Rev. A, 31, (1985); Lamacraft A., Phys. Rev. A, 77, (2008); Stamper-Kurn D.M., Ueda M., Rev. Mod. Phys., 85, (2013); Kawaguchi Y., Ueda M., Phys. Rep., 520, (2012); Kudo K., Kawaguchi Y., Phys. Rev. A, 84, (2011); Lakshmanan M., Nakamura K., Phys. Rev. Lett., 53, (1984)","","","American Physical Society","","","","","","24700045","","","","English","Phys. Rev. E","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85007416016" +"Anand M.; Carrey J.; Banerjee V.","Anand, Manish (57191479974); Carrey, Julian (6603792277); Banerjee, Varsha (6701838984)","57191479974; 6603792277; 6701838984","Role of dipolar interactions on morphologies and tunnel magnetoresistance in assemblies of magnetic nanoparticles","2018","Journal of Magnetism and Magnetic Materials","454","","","23","31","8","18","10.1016/j.jmmm.2018.01.027","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85041484634&doi=10.1016%2fj.jmmm.2018.01.027&partnerID=40&md5=ceef2efec5c6dcc964d2508b85b64149","Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India; Universite de Toulouse, INSA, UPS, Laboratoire de Physique et Chemie des Nano-Objects (LPCNO), 135 Avenue de Rangueil, Toulouse, F-31077, France","Anand M., Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India; Carrey J., Universite de Toulouse, INSA, UPS, Laboratoire de Physique et Chemie des Nano-Objects (LPCNO), 135 Avenue de Rangueil, Toulouse, F-31077, France; Banerjee V., Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India","We undertake comprehensive simulations of 2d arrays (Lx×Ly) of magnetic nanoparticles (MNPs) with dipole-dipole interactions by solving LLG equations. Our primary interest is to understand the correspondence between equilibrium spin (ES) morphologies and tunnel magnetoresistance (TMR) as a function of Θ – the ratio of the dipolar to the anisotropy strength, sample size Lx, aspect ratio Ar=Ly/Lx and the direction of the applied field H→=HêH. The parameter Θ is varied by choosing three distinct particles: (i) α-Fe2O3 (Θ≃0), (ii) Co (Θ≃0.37) and (iii) Fe3O4 (Θ≃1.28). Our main observations are as follows: (a) For weakly interacting spins (Θ≃0), the morphology has randomly oriented magnetic moments for all sample sizes and aspect ratios. The TMR exhibits a peak value of 50% at the coercive field Hc. It is robust with respect to Lx and Ar, and isotropic with respect to êH. (b) For strong interactions (Θ>1), the moments order in the plane of the sample. The ES morphology comprises of magnetically aligned regions interspersed with flux closure loops. For fields along x or y, the maximum TMR amplitude decrease to ∼30%. For êH=ẑ it drops to ∼3%. The TMR is robust with respect to Lx and Ar and isotropic in the x and y directions only. (c) In strongly interacting samples (Θ>1) with Lx comparable to the size of a flux closure loop, increasing Ar creates ferromagnetic chains in the sample oriented along y or -y. Consequently, for êH=ŷ the TMR magnitude for Ar=1 is ∼33% while that for Ar=32 drops to ∼16%. For êH=x̂ on the other hand, it is ∼30% and independent of Ar. The TMR of long ribbons of MNPs has a strong dependence on Ar and is anisotropic in all three directions. © 2018 Elsevier B.V.","","Anisotropy; Drops; Iron compounds; Magnetic moments; Magnetism; Magnetoresistance; Morphology; Nanomagnetics; Nanoparticles; Sampling; Tunnelling magnetoresistance; Anisotropy strengths; Dipolar interaction; Dipole dipole interactions; Ferromagnetic chains; Magnetic nano-particles; Magnetic nanoparti cles (MNPs); Strong dependences; Tunnel magnetoresistance; Aspect ratio","","","","","Indo-French Centre for Advanced Scientific Research; Department of Science and Technology, Ministry of Science and Technology, India, डीएसटी","The authors acknowledge partial financial support from the Indo-French Centre for Advanced Scientific Research, India. M.A. and V.B. also acknowledge partial financial support from the Department of Science and Technology (DST), India.","Zutic I., Fabian J., Sharma S.D., Spintronics: fundamentals and applications, Rev. Mod. 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Phys. D: Appl. Phys., 43, (2010); Kechrakos D., Trohidou K.N., Correlation between tunneling magnetoresistance and magnetization in dipolar-coupled nanoparticle arrays, Phys. Rev. B, 71, (2005); Kechrakos D., Trohidou K.N., Dipolar interaction effects in the magnetic and magnetotransport properties of ordered nanoparticle arrays, J. Nanosci. Nanotechnol., 8, pp. 1-15, (2008); Yang Y., Shen S., Ye Q., Lin L., Huang Z., The roles of the exchange and dipole couplings on the magnetoresistance for the nanoparticle arrays, J. Magn. Magn. Mater., 303, (2006); Wang W., Yu M., Batzill M., He J., Diebold U., Tang J., Enhanced tunneling magnetoresistance and high-spin polarization at room temperature in a polystyrene-coated Fe3O4 granular system, Phys. Rev. B, 73, (2006); Held G.A., Grinstein G., Doyle H., Sun S., Murray C.B., Competing interactions in dispersions of superparamagnetic nanoparticles, Phys. Rev. B, 64, (2001); Donahue M.J., Porter D.G., (1999); Bedanta S., Kleemann W., Supermagnetism, J. Phys. D: Appl. Phys., 42, (2009); Haase C., Nowak U., Role of dipole-dipole interactions for hyperthermia heating of magnetic nanoparticle ensembles, Phys. Rev. B, 85, (2012); Dantas C.C., de Andrade L.A., Micromagnetic simulations of small arrays of submicron ferromagnetic particles, Phys. Rev. B, 78, (2008); Huang Z., Chen Z., Peng K., Wang D., Zhang F., Zhang W., Du Y., Monte Carlo simulation of tunneling magnetoresistance in nanostructured materials, Phys. Rev. B, 69, (2004); Anand M., Carrey J., Banerjee V., Spin morphologies and heat dissipation in spherical assemblies of magnetic nanoparticles, Phys. Rev. B, 94, (2016); Usov N.A., Grebenshchikov Y.B., Hysteresis loops of an assembly of superparamagnetic nanoparticles with uniaxial anisotropy, J. Appl. Phys., 106, (2009); Carrey J., Mehdaoui B., Respaud M., Simple models for dynamic hysteresis loop calculations of magnetic single-domain nanoparticles: application to magnetic hyperthermia optimization, J. Appl. Phys., 109, (2011); Stoner C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Trans. R. Soc. A, 240, (1948)","V. Banerjee; Department of Physics, Indian Institute of Technology, New Delhi, Hauz Khas, 110016, India; email: varsha@physics.iitd.ac.in","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85041484634" +"Goldys B.; Le K.-N.; Tran T.","Goldys, Beniamin (6603793051); Le, Kim-Ngan (55844726000); Tran, Thanh (22836660000)","6603793051; 55844726000; 22836660000","A finite element approximation for the stochastic Landau-Lifshitz-Gilbert equation","2016","Journal of Differential Equations","260","2","","937","970","33","19","10.1016/j.jde.2015.09.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84947869797&doi=10.1016%2fj.jde.2015.09.012&partnerID=40&md5=a2adb9941610d1d4890ae42ba400b21f","School of Mathematics and Statistics, The University of Sydney, Sydney, 2006, Australia; School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia","Goldys B., School of Mathematics and Statistics, The University of Sydney, Sydney, 2006, Australia; Le K.-N., School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia; Tran T., School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia","The stochastic Landau-Lifshitz-Gilbert (LLG) equation describes the behaviour of the magnetisation under the influence of the effective field containing random fluctuations. We first transform the stochastic LLG equation into a partial differential equation with random coefficients (without the Itô term). The resulting equation has time-differentiable solutions. We then propose a convergent θ-linear scheme for the numerical solution of the reformulated equation. As a consequence, we show the existence of weak martingale solutions to the stochastic LLG equation. A salient feature of this scheme is that it does not involve solving a system of nonlinear algebraic equations, and that no condition on time and space steps is required when θ∈(1/2,1]. Numerical results are presented to show the applicability of the method. © 2015 Elsevier Inc.","Ferromagnetism; Finite element; Landau-Lifshitz-Gilbert equation; Primary; Secondary; Stochastic partial differential equation","","","","","","Australian Research Council, ARC, (DP120101886)","The authors acknowledge financial support through the ARC project DP120101886 . They thank the anonymous referee for pointing out a pitfall in the manuscript and for his constructive criticisms which help to improve the presentation of the paper. ","Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Bouard A.D., Hocquet A., A semi-discrete scheme for the stochastic Landau-Lifshitz equation; Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci., 16, pp. 299-316, (2006); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and nonuniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Banas L., Brzezniak Z., Neklyudov M., Prohl A., Stochastic Ferromagnetism - Analysis and Numerics, De Gruyter Stud. Math., 58, (2013); Banas L., Brzezniak Z., Prohl A., Computational studies for the stochastic Landau-Lifshitz-Gilbert equation, SIAM J. Sci. Comput., 35, pp. B62-B81, (2013); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, pp. 220-238, (2005); Banas L., Brzezniak Z., Prohl A., Neklyudov M., A convergent finite-element-based discretization of the stochastic Landau-Lifshitz-Gilbert equation, IMA J. Numer. Anal., 34, pp. 502-549, (2014); Billingsley P., Convergence of Probability Measures, Wiley Ser. Probab. Stat., (1999); Brzezniak Z., Goldys B., Jegaraj T., Weak solutions of a stochastic Landau-Lifshitz-Gilbert equation, Appl. Math. Res. Express. AMRX, pp. 1-33, (2012); Chen Z., Finite Element Methods and Their Applications, Sci. Comput., (2005); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng., 15, pp. 277-309, (2008); Da Prato G., Zabczyk J., Stochastic Equations in Infinite Dimensions, Encyclopedia Math. Appl., 44, (1992); Flandoli F., Gatarek D., Martingale and stationary solutions for stochastic Navier-Stokes equations, Probab. Theory Related Fields, 102, pp. 367-391, (1995); Gilbert T., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev., 100, pp. 1243-1255, (1955); Guo B., Pu X., Stochastic Landau-Lifshitz equation, Differential Integral Equations, 22, pp. 251-274, (2009); Johnson C., Numerical Solution of Partial Differential Equations by the Finite Element Method, (1987); Landau L., Lifschitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-168, (1935); Le K.-N., Page M., Praetorius D., Tran T., On a decoupled linear FEM integrator for Eddy-current-LLG, Appl. Anal., (2014); Le K.-N., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz-Gilbert equations, Comput. Math. Appl., 66, pp. 1389-1402, (2013)","T. Tran; School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia; email: thanh.tran@unsw.edu.au","","Academic Press Inc.","","","","","","00220396","","JDEQA","","English","J. Differ. Equ.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-84947869797" +"Arun R.; Sabareesan P.; Daniel M.","Arun, R. (55433105300); Sabareesan, P. (35192369200); Daniel, M. (7202421120)","55433105300; 35192369200; 7202421120","Domain wall assisted GMR head with spin-Hall effect","2016","AIP Conference Proceedings","1728","","020565","","","","0","10.1063/1.4946616","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84984540711&doi=10.1063%2f1.4946616&partnerID=40&md5=4b5783c35dc93399fd5707cd145d17e8","Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India; Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur, 613 401, India; SNS Institutions, Coimbatore, Tamilnadu, 641 049, India","Arun R., Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India; Sabareesan P., Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur, 613 401, India; Daniel M., Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India, SNS Institutions, Coimbatore, Tamilnadu, 641 049, India","We theoretically study the dynamics of a field induced domain wall in the Py/Pt bi-layer structure in the presence of spin-Hall effect (SHE) by solving the Landau-Lifshitz-Gilbert (LLG) equation along with the adiabatic, nonadiabatic and SHE spin-Transfer torques (STTs). It is observed that a weak magnetic field moves the domain wall with high velocity in the presence of SHE and the direction of the velocity is changed by changing the direction of the weak field. The numerical results show that the magnetization of the ferromagnetic layer can be reversed quickly through domain wall motion by changing the direction of a weak external field in the presence of SHE while the direction of current is fixed. The SHE reduces the magnetization reversal time of 1000nm length strip by 14.7ns. This study is extended to model a domain wall based GMR (Giant Magnetoresistance) read head with SHE. © 2016 Author(s).","","","","","","","","","Catalan R.R.G., Seidel J., Scott J.F., Rev. Mod. Phys., 84, (2012); Li Z., Zhang S., Phys. Rev. B, 70, (2004); Mougin J.P.A.P.J.M.A., Cormier M., Ferre J., Europhys. Lett., 78, (2007); Liu Y.L., Pai C.-F., Buhrman R.A., Science, 336, (2012); Seo S.-M., Kim K.-W., Ryu J., Lee H.-W., Lee K.-J., Appl. Phys. Lett., 101, (2012); Schryer N.L., Walker L.R., J. Appl. Phys., 45, (1974); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Arun R., Sabareesan P., Daniel M., PRAMANA, 85, (2015); Grollier V.C., Boulenc P., Faini G., Appl. Phys. Lett., 83, (2003)","R. Arun; Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli, 620 024, India; email: danielcnld@gmail.com","Shekhawat M.S.; Bhardwaj S.; Suthar B.","American Institute of Physics Inc.","DAE-BRNS; DRDO; DST; ISRO","International Conference on Condensed Matter and Applied Physics, ICC 2015","30 October 2015 through 31 October 2015","Bikaner","121744","0094243X","978-073541375-7","","","English","AIP Conf. Proc.","Conference paper","Final","","Scopus","2-s2.0-84984540711" +"Thibaudeau P.; Nussle T.; Nicolis S.","Thibaudeau, Pascal (6507649761); Nussle, Thomas (57193273430); Nicolis, Stam (57203886320)","6507649761; 57193273430; 57203886320","Nambu mechanics for stochastic magnetization dynamics","2017","Journal of Magnetism and Magnetic Materials","432","","","175","180","5","3","10.1016/j.jmmm.2017.01.088","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85012298613&doi=10.1016%2fj.jmmm.2017.01.088&partnerID=40&md5=1d084031de5109c55eb03dc420fe671f","CEA DAM/Le Ripault, BP 16, Monts, F-37260, France; CNRS-Laboratoire de Mathématiques et Physique Théorique (UMR 7350), Fédération de Recherche “Denis Poisson” (FR2964), Département de Physique, Université de Tours, Parc de Grandmont, Tours, F-37200, France","Thibaudeau P., CEA DAM/Le Ripault, BP 16, Monts, F-37260, France; Nussle T., CEA DAM/Le Ripault, BP 16, Monts, F-37260, France, CNRS-Laboratoire de Mathématiques et Physique Théorique (UMR 7350), Fédération de Recherche “Denis Poisson” (FR2964), Département de Physique, Université de Tours, Parc de Grandmont, Tours, F-37200, France; Nicolis S., CNRS-Laboratoire de Mathématiques et Physique Théorique (UMR 7350), Fédération de Recherche “Denis Poisson” (FR2964), Département de Physique, Université de Tours, Parc de Grandmont, Tours, F-37200, France","The Landau–Lifshitz–Gilbert (LLG) equation describes the dynamics of a damped magnetization vector that can be understood as a generalization of Larmor spin precession. The LLG equation cannot be deduced from the Hamiltonian framework, by introducing a coupling to a usual bath, but requires the introduction of additional constraints. It is shown that these constraints can be formulated elegantly and consistently in the framework of dissipative Nambu mechanics. This has many consequences for both the variational principle and for topological aspects of hidden symmetries that control conserved quantities. We particularly study how the damping terms of dissipative Nambu mechanics affect the consistent interaction of magnetic systems with stochastic reservoirs and derive a master equation for the magnetization. The proposals are supported by numerical studies using symplectic integrators that preserve the topological structure of Nambu equations. These results are compared to computations performed by direct sampling of the stochastic equations and by using closure assumptions for the moment equations, deduced from the master equation. © 2017 Elsevier B.V.","Fokker–Planck equation; Magnetic ordering; Magnetization dynamics","Dynamics; Fokker Planck equation; Hamiltonians; Magnetization; Mechanics; Spin dynamics; Topology; Closure assumptions; Magnetization dynamics; Magnetization vector; Planck equation; Stochastic equations; Symplectic integrators; Topological structure; Variational principles; Stochastic systems","","","","","","","Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Aharoni A., Introduction to the Theory of Ferromagnetism, (2000); Miltat J., Albuquerque G., Thiaville A., Vouille C., Spin transfer into an inhomogeneous magnetization distribution, J. Appl. Phys., 89, 11, (2001); Berkov D.V., Miltat J., Spin-torque driven magnetization dynamics: micromagnetic modeling, J. Magn. Magn. Mater., 320, 7, pp. 1238-1259, (2008); Holyst J.A., Turski L.A., Dissipative dynamics of quantum spin systems, Phys. Rev. A, 45, 9, pp. 6180-6184, (1992); Turski L.A., Dissipative quantum mechanics, From Quantum Mechanics to Technology, number 477 in Lecture Notes in Physics, pp. 347-357, (1996); Sonnet Nguyen Q.H., Turski L.A., On the Dirac approach to constrained dissipative dynamics, J. Phys. A: Math. Gen., 34, 43, pp. 9281-9302, (2001); de Azcarraga J.A., Izquierdo J.M., N -ary algebras: a review with applications, J. Phys. A: Math. Theor., 43, 29, (2010); Nambu Y., Generalized Hamiltonian dynamics, Phys. Rev. D, 7, 8, pp. 2405-2412, (1973); Ibanez R., de Leon M., Marrero J.C., de Diego D.M., Dynamics of generalized Poisson and Nambu–Poisson brackets, J. Math. Phys., 38, 5, (1997); Marsden J.E., Ratiu T.S., Introduction to Mechanics and Symmetry, Texts in Applied Mathematics, 17, (1999); Griffiths P., Harris J., (2014); Axenides M., Floratos E., Strange attractors in dissipative Nambu mechanics: classical and quantum aspects, J. High Energy Phys., 2010, 4, (2010); Tranchida J., Thibaudeau P., Nicolis S., Quantum magnets and matrix lorenz systems, J. Phys: Conf. Ser., 574, 1, (2015); Uhlenbeck G.E., Ornstein L.S., On the theory of the Brownian motion, Phys. Rev., 36, 5, pp. 823-841, (1930); Thibaudeau P., Beaujouan D., Thermostatting the atomic spin dynamics from controlled demons, Physica A, 391, 5, pp. 1963-1971, (2012); Walton D., Rate of transition for single domain particles, J. Magn. Magn. Mater., 62, 2-3, pp. 392-396, (1986); Shapiro V.E., Loginov V.M., Formulae of differentiation and their use for solving stochastic equations, Physica A, 91, 3-4, pp. 563-574, (1978); Furutsu K., On the statistical theory of electromagnetic waves in a fluctuating medium (I), J. Res. Nat. Bur. Stand., 67D, pp. 303-323, (1963); Novikov E.A., Functionals and the random-force method in turbulence theory, Sov. Phys. J. Exp. Theor. Phys., 20, 5, pp. 1290-1294, (1964); Klyatskin V.I., Stochastic Equations through the Eye of the Physicist: Basic Concepts, Exact Results and Asymptotic Approximations, (2005); Risken H., The Fokker–Planck Equation, Springer Series in Synergetics, 18, (1989); Tranchida J., Thibaudeau P., Nicolis S., Closing the hierarchy for non-Markovian magnetization dynamics, Physica B, 486, pp. 57-59, (2016); Garanin D.A., Fokker–Planck and Landau–Lifshitz–Bloch equations for classical ferromagnets, Phys. Rev. B, 55, 5, pp. 3050-3057, (1997); Ma P.-W., Dudarev S.L., Langevin spin dynamics, Phys. Rev. B, 83, (2011); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, 5, pp. 1677-1686, (1963); Zinn-Justin J., Quantum Field Theory and Critical Phenomena, Number 113 in International Series of Monographs on Physics, (2011); Garca-Palacios J.L., Lazaro F.J., Langevin-dynamics study of the dynamical properties of small magnetic particles, Phys. Rev. B, 58, 22, pp. 14937-14958, (1998); Thibaudeau P., Tranchida J., Nicolis S., Non-markovian magnetization dynamics for uniaxial nanomagnets, IEEE Trans. Magn., 52, 7, pp. 1-4, (2016); Tranchida J., Thibaudeau P., Nicolis S., Colored-noise magnetization dynamics: from weakly to strongly correlated noise, IEEE Trans. Magn., 52, 7, (2016); Lyberatos A., Berkov D.V., Chantrell R.W., A method for the numerical simulation of the thermal magnetization fluctuations in micromagnetics, J. Phys.: Condens. Matter, 5, 47, pp. 8911-8920, (1993); Kamppeter T., Mertens F.G., Moro E., Sanchez A., Bishop A.R., Stochastic vortex dynamics in two-dimensional easy-plane ferromagnets: multiplicative versus additive noise, Phys. Rev. B, 59, 17, pp. 11349-11357, (1999)","P. Thibaudeau; CEA DAM/Le Ripault, Monts, BP 16, F-37260, France; email: pascal.thibaudeau@cea.fr","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85012298613" +"Wen H.-Y.; Xia J.-B.","Wen, Hong-Yu (57194171417); Xia, Jian-Bai (55557360500)","57194171417; 55557360500","Control of spins in a nano-sized magnet using electric-current","2017","Chinese Physics B","26","4","047501","","","","1","10.1088/1674-1056/26/4/047501","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85019011829&doi=10.1088%2f1674-1056%2f26%2f4%2f047501&partnerID=40&md5=e7ce418edc4bd064aaaa73efee41885e","State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","Wen H.-Y., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; Xia J.-B., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","In this paper the LandauLifshitzGilbert equation including the torque term is used to investigate the magnetic moment dynamics in the free layer of the ferromagnet/non-magnetic/ferromagnet (FM1/N/FM2) structures. It is found that the reverse critical time τc decreases with the current increasing. The critical time τc as a function of current for the perpendicular and parallel easy magnetic axes are the same. The critical time τc increases with the damping factor α increasing. In the case of large current the influence of the damping factor α is smaller, but in the case of little torque the critical time τc increases greatly with the damping increasing. The direction of the magnetization in the fixed layer influences the critical time, when the angle between the magnetization and the z direction changes from 0.1p to 0.4p, the critical time τc decreases from 26.7 to 15.6. © 2017 Chinese Physical Society and IOP Publishing Ltd.","LandauLifshitzGilbert (LLG) equation; magnetization switching; spin transfer torque","Damping; Magnetic moments; Magnetization; Critical time; Damping factors; Ferromagnets; LandauLifshitzGilbert (LLG) equation; Large current; Magnetic axes; Magnetization switching; Spin transfer torque; Magnets","","","","","","","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev., 54, (1996); Chappert C., Fert A., Van Nguyen D.F., Nat. Mater., 6, (2007); Myers E.B., Ralph D.C., Katine J.A., Louie R.N., Buhrman R.A., Science, 285, (1999); Dieny B., Sousa R.C., Herault J., Papusoi C., Prenat G., Ebels U., Houssameddine D., Rodmacq B., Auffret S., Prejbeanu-Buda L., Cyrille M.C., Delaet B., Redon O., Ducruet C., Nozieres J.P., Prejbeanu L., Int. J. Nanotech., 7, (2010); Chernyshov A., Overby M., Liu X., Furdyna J.K., Lyanda-Geller Y., Rokhinson L.P., Nat. Phys., 5, (2009); Miron I.M., Garello K., Gaudin G., Zermatten P.J., Costache M.V., Auffret S., Bandiera S., Rodmacq B., Schuhl A., Gambardella P., Nature, 476, (2011); Bao J., Xu X.G., Jiang Y., Acta Phys. Sin., 58, (2009); Diao Z.T., Li Z.J., Wang S.Y., Ding Y.F., Panchula A., Chen E., Wang L.C., Huai Y.M., J. Phys.: Condens. Matter, 19, 16, (2007); Safeer C.K., Jue E., Lopez A., Buda-Prejbeanu L., Auffret S., Pizzini S., Boulle O., Miron I.M., Gaudin G., Nat. Nanotechnol., 11, (2016); Zhang X.L., Wang C.J., Liu Y.W., Zhang Z.Z., Jin Q.Y., Duan C.G., Sci. Rep., 6, (2016); Chiba D., Sato Y., Kita T., Matsukura F., Ohno H., Phys. Rev. Lett., 93, (2004); Tatara G., Kohno H., Phys. Rev. Lett., 92, (2004); Ohno H., Dietl T., J. Magn. Magn. Mater., 320, (2008); Dietl T., Ohno H., Rev. Mod. Phys., 86, (2014); Jungwirth T., Wunderlich J., Novak V., Olejnik K., Gallagher B.L., Campion R.P., Edmonds K.W., Rushforth A.W., Rev. Mod. Phys., 86, (2014); Tomita H., Miwa S., Nozaki T., Yamashital S., Nagase T., Nishiyama K., Kitagawa K., Yoshikawa M., Daibou T., Nagamine M., Kishi T., Ikegawa S., Shimomura N., Yoda H., Suzuki Y., Appl. Phys. Lett., 102, (2013); Ikeda S., Miura K., Yamamoto H., Mizunuma K., Gan H.D., Endo M., Kanai S., Hayakawa J., Matsukura F., Ohno H., Nat. Mater., 9, (2010); Sato H., Enobio E.C.I., Yamanouchi M., Ikeda S., Fukami S., Kanai S., Matsukura F., Ohno H., Appl. Phys. Lett., 105, (2014)","J.-B. Xia; State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; email: xiajb@semi.ac.cn","","Institute of Physics Publishing","","","","","","16741056","","","","English","Chin. Phys.","Article","Final","","Scopus","2-s2.0-85019011829" +"Miyashita S.; Nishino M.; Toga Y.; Hinokihara T.; Miyake T.; Hirosawa S.; Sakuma A.","Miyashita, Seiji (7102333760); Nishino, Masamichi (7103009415); Toga, Yuta (26532037600); Hinokihara, Taichi (55329793900); Miyake, Takashi (7202951411); Hirosawa, Satoshi (7103189702); Sakuma, Akimasa (7102719646)","7102333760; 7103009415; 26532037600; 55329793900; 7202951411; 7103189702; 7102719646","Perspectives of stochastic micromagnetism of Nd2Fe14B and computation of thermally activated reversal process","2018","Scripta Materialia","154","","","259","265","6","29","10.1016/j.scriptamat.2017.11.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85039065448&doi=10.1016%2fj.scriptamat.2017.11.012&partnerID=40&md5=a131c7e0c36bdd20a58a7b8df55a7258","Department of Physics, Graduate School of Science, The University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan; Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan; International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan; CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8568, Ibaraki, Japan; Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan","Miyashita S., Department of Physics, Graduate School of Science, The University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan, Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan; Nishino M., Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan; Toga Y., Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan; Hinokihara T., Department of Physics, Graduate School of Science, The University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan, Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan; Miyake T., Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan, CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8568, Ibaraki, Japan; Hirosawa S., Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan; Sakuma A., Elements Strategy Initiative Center for Magnetic Materials (ESICMM), National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki, Japan, Department of Applied Physics, Tohoku University, Sendai, 980-8579, Japan","The thermal and dynamical properties Nd2Fe14B at finite temperatures are studied with an atomic model Hamiltonian. The temperature dependence of the magnetization including the reorientation transition was obtained successfully. Moreover, the atom-specific observation revealed that the Nd magnetic moment decreases fast with the temperature. Temperature dependence of the domain wall structures was also obtained. Beside the static thermal properties, dynamics of the magnetization in unfavorable magnetic field was studied by stochastic LLG equation and Monte Carlo method. The field and size-dependences of the relaxation time at finite temperatures are discussed including the effects of the dipole-dipole interaction. © 2017 Acta Materialia Inc.","Atomistic model; Magnetization reversal; Nd2Fe14B; Size dependence of coercive force at finite temperatures; Stochastic LLG equation","Iron compounds; Magnetic moments; Magnetization reversal; Monte Carlo methods; Neodymium compounds; Stochastic models; Stochastic systems; Temperature distribution; Atomistic modeling; Dipole dipole interactions; Domain wall structures; Dynamical properties; Finite temperatures; LLG equation; Nd2Fe14B; Temperature dependence; Boron compounds","","","","","Japan Society for the Promotion of Science, JSPS, (17K05508); Ministry of Education, Culture, Sports, Science and Technology, Monbusho; University of Tokyo","Funding text 1: The present work was supported by the Elements Strategy Initiative Center for Magnetic Materials under the outsourcing project of MEXT. The authors thank the Supercomputer Center, Institute for Solid State Physics, The University of Tokyo, for the use of the facilities.; Funding text 2: The present work was supported by the Elements Strategy Initiative Center for Magnetic Materials under the outsourcing project of MEXT . The authors thank the Supercomputer Center, Institute for Solid State Physics, The University of Tokyo, for the use of the facilities.","Sagawa M., Fujimura S., Yamamoto H., Matsuura Y., Hiraga K., IEEE Trans. Magn., 20, (1984); Croat J.J., Herbst J.F., Lee R.W., Pinkerton F.E., J. Appl. Phys., 55, (1984); Givord D., Li H.S., Perrier de la Bathie R., Solid State Commun., 51, (1984); Hirosawa S., Matsuura Y., Yamamoto H., Fujimura S., Sagawa M., Yamauchi H., J. Appl. Phys., 59, (1986); Lee R.W., Appl. Phys. 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Phys., 111, (2012)","S. Miyashita; Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Bunkyo-Ku, 113-0033, Japan; email: miya@spin.phys.s.u-tokyo.ac.jp","","Acta Materialia Inc","","","","","","13596462","","SCMAF","","English","Scripta Mater","Article","Final","","Scopus","2-s2.0-85039065448" +"Yurov A.V.; Yurov V.A.","Yurov, Artyom V. (6701637622); Yurov, Valerian A. (59157799300)","6701637622; 59157799300","The Landau-Lifshitz equation, the NLS, and the magnetic rogue wave as a by-product of two colliding regular ""positons""","2018","Symmetry","10","4","82","","","","7","10.3390/sym10040082","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85046103761&doi=10.3390%2fsym10040082&partnerID=40&md5=fe1c904e2c42684e5a7cc3c5dcbc70d1","Department of Physics, Mathematics and Informational Technology, Immanuel Kant Baltic Federal University, Al. Nevsky St. 14, Kaliningrad, 236041, Russian Federation; Functionalized Magnetic Materials for Biomedicine and Nanotechnology Center, Department of Physics, Mathematics and Informational Technology, Immanuel Kant Baltic Federal University, Mathematics and IT, Al. Nevsky St. 14, Kaliningrad, 236041, Russian Federation","Yurov A.V., Department of Physics, Mathematics and Informational Technology, Immanuel Kant Baltic Federal University, Al. Nevsky St. 14, Kaliningrad, 236041, Russian Federation; Yurov V.A., Functionalized Magnetic Materials for Biomedicine and Nanotechnology Center, Department of Physics, Mathematics and Informational Technology, Immanuel Kant Baltic Federal University, Mathematics and IT, Al. Nevsky St. 14, Kaliningrad, 236041, Russian Federation","In this article we present a new method for construction of exact solutions of the Landau-Lifshitz-Gilbert equation (LLG) for ferromagnetic nanowires. The method is based on the established relationship between the LLG and the nonlinear Schrödinger equation (NLS), and is aimed at resolving an old problem: how to produce multiple-rogue wave solutions of NLS using just the Darboux-type transformations. The solutions of this type-known as P-breathers-have been proven to exist by Dubard and Matveev, but their technique heavily relied on using the solutions of yet another nonlinear equation, the Kadomtsev-Petviashvili I equation (KP-I), and its relationship with NLS.We have shown that in fact one doesn't have to use KP-I but can instead reach the same results just with NLS solutions, but only if they are dressed via the binary Darboux transformation. In particular, our approach allows us to construct all the Dubard-Matveev P-breathers. Furthermore, the new method can lead to some completely new, previously unknown solutions. One particular solution that we have constructed describes two ""positon""-like waves, colliding with each other and in the process producing a new, short-lived rogue wave. We called this unusual solution (in which a rogue wave is begotten after the impact of two solitons) the ""impacton"". © 2018 by the authors.","Darboux transformation; Landau-Lifshitz-Gilbert equation; Nonlinear Schrödinger equation; P-breathers; Positons","","","","","","","","Darboux G., Sur une proposition relative aux équations linéares, C. R. Acad. Sci, 94, pp. 1456-1459, (1882); Darboux G., Theórie Générale des Surfaces, (1972); Infeld L., Hull T.E., The Factorization Method, Rev. Mod. Phys, 23, (1951); Schulze-Halberg A., Jimenez J.M.C., Supersymmetry of Generalized Linear Schrödinger Equations in (1+1) Dimensions, Symmetry, 1, pp. 115-144, (2009); Beckers J., Debergh N., Parastatistics and supersymmetry in quantum mechanics, Nucl. Phys. B, 340, pp. 767-776, (1990); Andrianov A.A., Ioffe M.V., From supersymmetric quantum mechanics to a parasupersymmetric one, Phys. Lett. B, 255, pp. 543-548, (1990); Yurova A.A., Yurov A.V., Yurov V.A., When the supersymmetry is not enough: The parasupersymmetric algebras of the Boussinesq equations, TASK Q, 20, pp. 241-248, (2016); Veselov A.P., Shabat A.B., Dressing chains and the spectral theory of the Schrödinger operator, Funct. Anal. Appl, 27, pp. 81-96, (1993); Matveev V.B., Positon-positon and soliton-positon collisions: KdV case, Phys. Lett. A, 166, pp. 209-212, (1992); Borisov A.B., Zykov S.A., The dressing chain of discrete symmetries and proliferation of nonlinear equations, Theor. Math. Phys, 115, pp. 530-541, (1998); Shabat A.B., Third version of the dressing method, Theor. Math. Phys, 121, pp. 1397-1408, (1999); Yurov A.V., Discrete symmetry's chains and links between integrable equations, J. Math. Phys, 44, pp. 1183-1201, (2003); Landau L.D., Lifshitz E.M., Theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowietunion, 8, pp. 153-169, (1935); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Mag, 40, pp. 3443-3449, (1935); Visintin A., Modified Landau-Lifshitz equation for ferromagnetism, Physica B, 233, pp. 365-369, (1997); Lakshmanan M., Continuum spin system as an exactly solvable dynamical system, Phys. Lett. A, 61, pp. 53-54, (1997); Zakharov V.E., Takhtadzhyan A., Equivalence of the nonlinear Schrödinger equation and the equation of a Heisenberg ferromagnet, Theor. Math. Phys, 38, pp. 17-23, (1979); Kundu A., Landau-Lifshitz and higher-order nonlinear systems gauge generated from nonlinear Schrödinger type equations, J. Math. Phys, 25, pp. 3433-3438, (1984); Zhaoa F., Lia Z.D., Lia Q.Y., Wenb L., Fua G., Liu W.M., Magnetic rogue wave in a perpendicular anisotropic ferromagnetic nanowire with spin-transfer torque, Ann. Phys, 327, pp. 2085-2095, (2012); Giridharan D., Sabareesan P., Daniel M., Soliton solution for the Landau-Lifshitz equation of a one-dimensional bicomponent magnonic crystal, Phys. Rev. E, 94, (2016); Gerasimchuk I.V., Gorobets Y.I., Gerasimchuk V.S., Nonlinear Schrödinger Equation for Description of Small-amplitude SpinWaves inMultilayerMagneticMaterials, J. Nano Electron. Phys, 8, (2016); Kosevich A.M., Ivanov B.A., Kovalev A.S., Magnetic Solitons, Phys. Rep, 194, pp. 117-238, (1990); Peregrine D.H., Water waves, nonlinear Schrödinger equations and their solutions, J. Aust. Math. Soc. B, 25, pp. 16-43, (1983); Hansteen O.E., Jostad H.P., Tjelta T.I., Observed Platform response to a 'monster' wave, Proceedings of the Sixth International Symposium on Field Measurements in Geomechanics, pp. 73-86, (2003); Kibler B., Fatome J., Finot C., Millot G., Dias F., Genty G., Akhmediev N., Dudley J.M., The Peregrine soliton in nonlinear fibre optics, Nat. Phys, 6, pp. 790-795, (2010); Bailung H., Sharma S.K., Nakamura Y., Observation of Peregrine solitons in a multicomponent plasma with negative ion, Phys. Rev. Lett, 107, (2011); Chabchoub A., Hoffmann N.P., Akhmediev N., Rogue wave observation in a water wave tank, Phys. Rev. Lett, 106, (2011); Dubard P., Gaillard P., Klein C., Matveev V., On multi-rogue wave solutions of the NLS equation and positon solutions of the KdV equation, Eur. Phys. J. Spec. Top, 185, pp. 247-258, (2010); Dubard P., Matveev V.B., Multi-rogue waves solutions to the focusing NLS equation and the KP-I equation, Nat. Hazards Earth Syst. Sci, 11, pp. 667-672, (2011); Matveev V.B., Salle M.A., Darboux Transformation and Solitons, (1991); Matveev V.B., Positons: Slowly Decreasing Analogues of Solitons, Theor. Math. Phys, 131, pp. 483-497, (2002); Yurova A.A., Yurov A.V., Rudnev M., Darboux transformation for classical acoustic spectral problem, IJMMS, 49, pp. 3123-3142, (2003); Beutler R., Positon solutions of the sine-Gordon equation, J. Math. Phys, 34, pp. 3098-3109, (1993); Jaworski M., Zagrodzinski J., Positon and positon-like solutions of the Korteweg-de Vries and Sine-Gordon equations, Chaos Sol. Fract, 5, pp. 2229-2233, (1995); Aranson I.S., Kramer L., The world of the complex Ginzburg-Landau equation, Rev. Mod. Phys, 74, (2002); Tajiri M., On Soliton Solutions of the Nonlinear Coupled Klein-Gordon Equation, J. Phys. Soc. Jpn, 52, pp. 3722-3726, (1983)","V.A. Yurov; Functionalized Magnetic Materials for Biomedicine and Nanotechnology Center, Department of Physics, Mathematics and Informational Technology, Immanuel Kant Baltic Federal University, Mathematics and IT, Kaliningrad, Al. Nevsky St. 14, 236041, Russian Federation; email: vayt37@gmail.com","","MDPI AG","","","","","","20738994","","","","English","Symmetry","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85046103761" +"Rossi J.O.; Yamasaki F.S.; Schamiloglu E.; Barroso J.J.","Rossi, J.O. (7202397572); Yamasaki, F.S. (49561878200); Schamiloglu, E. (7006390232); Barroso, J.J. (7103318266)","7202397572; 49561878200; 7006390232; 7103318266","Analysis of nonlinear gyromagnetic line operation using LLG equation","2017","IEEE International Pulsed Power Conference","2017-June","","8291172","","","","9","10.1109/PPC.2017.8291172","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85054289925&doi=10.1109%2fPPC.2017.8291172&partnerID=40&md5=8bd5f2c91e021986f2b8191f58da956b","National Institute for Space Research, Plasma Laboratory, PO Box 12245-970, Sao Jose dos Campos, Brazil; Electrical and Computer Eng. Department, University of New Mexico, Albuquerque, NM, United States; Division of Electronic Eng., Technological Institute of Aeronautics, Sao Jose dos Campos, SO, Brazil","Rossi J.O., National Institute for Space Research, Plasma Laboratory, PO Box 12245-970, Sao Jose dos Campos, Brazil; Yamasaki F.S., National Institute for Space Research, Plasma Laboratory, PO Box 12245-970, Sao Jose dos Campos, Brazil; Schamiloglu E., National Institute for Space Research, Plasma Laboratory, PO Box 12245-970, Sao Jose dos Campos, Brazil, Electrical and Computer Eng. Department, University of New Mexico, Albuquerque, NM, United States; Barroso J.J., National Institute for Space Research, Plasma Laboratory, PO Box 12245-970, Sao Jose dos Campos, Brazil, Division of Electronic Eng., Technological Institute of Aeronautics, Sao Jose dos Campos, SO, Brazil","This paper deals with the study of the gyromagnetic effect since it has proven to be an excellent way of generating radiofrequency (RF) using ferrite loaded nonlinear lines in the range of GHz. Using a proper mathematical model based on the analysis of the LLG (Landau-Lifshitz-Gilbert) equation will be demonstrated the dependence of the center frequency generated on both the intensity of the axial magnetic applied and the incident pulse amplitude. © 2017 IEEE.","","Centre frequency; Incident pulse; Landau-Lifshitz-Gilbert equations; Line operations; Model-based OPC; Pulse amplitude; Radiofrequencies; Nonlinear equations","","","","","SOARD-USAF, (FA9550-14-1-0133)","Work supported in part by SOARD-USAF under contract number FA9550-14-1-0133 [email: jose.rossi@inpe.br where Ht is the total effective magnetic field, Ȗ=1.76×1011 rad/s/T the electron gyromagnetic ratio, ȝ0 = 4ʌ×10-7 H/m the free space magnetic permeability, and Ms the medium saturated static magnetization (generally assumed 0.35 T for ferrites).","Yamasaki F.S., Schamiloglu E., Rossi J.O., Barroso J.J., Simulation studies of distributed nonlinear gyromagnetic lines based on lc lumped model, IEEE Trans. Plasma Sci, 44, 10, pp. 2232-2239, (2016); Bragg J.-W.B., Dickens J.C., Neuber A.A., Material selection considerations for coaxial ferrimagnetic-based nonlinear transmission lines, Journal of Applied Physics, 113, (2013); Karelin S.Y., Krasovitsky V.B., Magda I.I., Mukhin V.S., Sinitsin V.G., Rf oscillations in a coaxial transmission line with a saturated ferrite: 2-d simulation and experiment, 2016 8th International Conference on Ultrawideband and Ultrashort Impulse Signals, pp. 60-63; Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Yu., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, Journal of Applied Physics, 117, (2015)","","","Institute of Electrical and Electronics Engineers Inc.","","21st IEEE International Conference on Pulsed Power, PPC 2017","18 June 2017 through 22 June 2017","Brighton","134677","21584915","978-150905748-1","","","English","IEEE Int. Conf. Pulsed Power","Conference paper","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85054289925" +"Timopheev A.A.; Sousa R.; Chshiev M.; Buda-Prejbeanu L.D.; Dieny B.","Timopheev, A.A. (22982203600); Sousa, R. (35516516600); Chshiev, M. (6602894746); Buda-Prejbeanu, L.D. (11140986400); Dieny, B. (7005208439)","22982203600; 35516516600; 6602894746; 11140986400; 7005208439","Respective influence of in-plane and out-of-plane spin-transfer torques in magnetization switching of perpendicular magnetic tunnel junctions","2015","Physical Review B - Condensed Matter and Materials Physics","92","10","104430","","","","31","10.1103/PhysRevB.92.104430","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84943801798&doi=10.1103%2fPhysRevB.92.104430&partnerID=40&md5=c9382d9aa5d474f96a071f6accc39a58","Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France; CEA, INAC-SPINTEC, Grenoble, F-38000, France; CNRS, SPINTEC, Grenoble, F-38000, France","Timopheev A.A., Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France, CEA, INAC-SPINTEC, Grenoble, F-38000, France, CNRS, SPINTEC, Grenoble, F-38000, France; Sousa R., Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France, CEA, INAC-SPINTEC, Grenoble, F-38000, France, CNRS, SPINTEC, Grenoble, F-38000, France; Chshiev M., Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France, CEA, INAC-SPINTEC, Grenoble, F-38000, France, CNRS, SPINTEC, Grenoble, F-38000, France; Buda-Prejbeanu L.D., Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France, CEA, INAC-SPINTEC, Grenoble, F-38000, France, CNRS, SPINTEC, Grenoble, F-38000, France; Dieny B., Univ. Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France, CEA, INAC-SPINTEC, Grenoble, F-38000, France, CNRS, SPINTEC, Grenoble, F-38000, France","The relative contributions of in-plane (damping-like) and out-of-plane (field-like) spin-transfer torques (STT) in the magnetization switching of out-of-plane magnetized magnetic tunnel junctions (pMTJ) has been theoretically analyzed using the transformed Landau-Lifshitz-Gilbert (LLG) equation with the STT terms. It is demonstrated that in a pMTJ structure obeying macrospin dynamics, the out-of-plane torque influences the precession frequency, but it does not contribute significantly to the STT switching process (in particular to the switching time and switching current density), which is mostly determined by the in-plane STT contribution. This conclusion is confirmed by finite temperature and finite writing pulse macrospin simulations of the current field switching diagrams. It contrasts with the case of STT switching in in-plane magnetized magnetic tunnel junction (MTJ) in which the field-like term also influences the switching critical current. This theoretical analysis was successfully applied to the interpretation of voltage field STT switching diagrams experimentally measured on pMTJ pillars 36 nm in diameter, which exhibit macrospin behavior. The physical nonequivalence of Landau and Gilbert dissipation terms in the presence of STT-induced dynamics is also discussed. © 2015 American Physical Society.","","","","","","","; Horizon 2020 Framework Programme, H2020, (669204); Seventh Framework Programme, FP7, (600382); UK Research and Innovation, UKRI, (104426)","","Liu T., Zhang Y., Cai J.W., Pan H.Y., Sci. Rep., 4, (2014); Khvalkovskiy A.V., Apalkov D., Watts S., Chepulskii R., Beach R.S., Ong A., Tang X., Driskill-Smith A., Butler W.H., Visscher P.B., Lottis D., Chen E., Nikitin V., Krounbi M., J. Phys. D: Appl. 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Rev. Lett., 102, (2009)","","","American Physical Society","","","","","","10980121","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84943801798" +"Feischl M.; Tran T.","Feischl, Michael (52363525000); Tran, Thanh (22836660000)","52363525000; 22836660000","The eddy current-LLG equations: Fem-Bem coupling and a priori error estimates","2017","SIAM Journal on Numerical Analysis","55","4","","1786","1819","33","17","10.1137/16M1065161","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85028636669&doi=10.1137%2f16M1065161&partnerID=40&md5=1e5035c63621c426f14a3d0ced139282","School of Mathematics and Statistics, University of New South Wales, Sydney, 2052, Australia","Feischl M., School of Mathematics and Statistics, University of New South Wales, Sydney, 2052, Australia; Tran T., School of Mathematics and Statistics, University of New South Wales, Sydney, 2052, Australia","We analyze a numerical method for the coupled system of the eddy current equations in R3 with the Landau-Lifshitz-Gilbert equation in a bounded domain. The unbounded domain is discretized by means of finite-element/boundary-element coupling. Even though the considered problem is strongly nonlinear, the numerical approach is constructed such that only two linear systems per time step have to be solved. We prove unconditional weak convergence (of a subsequence) of the finite-element solutions towards a weak solution. We establish a priori error estimates if a sufficiently smooth strong solution exists. Numerical experiments underlining the theoretical results are presented. © 2017 Society for Industrial and Applied Mathematics.","A priori error estimate; Boundary element; Coupling; Eddy current; Ferromagnetism; Finite element; Landau-Lifshitz-Gilbert equation","Boundary element method; Couplings; Errors; Ferromagnetism; Finite element method; Linear systems; Numerical methods; Eddy-current equations; FEM-BEM coupling; Finite element solution; Landau-Lifshitz-Gilbert equations; Numerical approaches; Numerical experiments; Priori error estimate; Strongly nonlinear; Eddy currents","","","","","Australian Research Council, ARC, (DP120101886, DP160101755)","∗Received by the editors March 10, 2016; accepted for publication (in revised form) February 13, 2017; published electronically July 26, 2017. http://www.siam.org/journals/sinum/55-4/M106516.html Funding: The work of the authors was supported by the Australian Research Council under grant DP120101886 and DP160101755. †School of Mathematics and Statistics, The University of New South Wales, Sydney 2052, Australia (m.feischl@unsw.edu.au, thanh.tran@unsw.edu.au).","Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suss D., Spin-polarized transport in ferromagnetic multilayers: An unconditionally convergent FEM integrator, Comput. Math. Appl., 68, pp. 639-654, (2014); Adams R.A., Sobolev spaces, Pure Appl. Math., 65, (1975); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Kritsikis E., Steiner J., Toussaint J.-C., A convergent and precise finite element scheme for Landau-Lifschitz-Gilbert equation, Numer. Math., 128, pp. 407-430, (2014); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Aurada M., Feischl M., Praetorius D., Convergence of some adaptive FEM-BEM cou-pling for elliptic but possibly nonlinear interface problems, ESAIM Math. Model. Numer. Anal., 46, pp. 1147-1173, (2012); Banas L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation, SIAM J. Numer. 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Software, 41, (2015); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Japan J. Appl. Math., 2, pp. 69-84, (1985)","M. Feischl; School of Mathematics and Statistics, University of New South Wales, Sydney, 2052, Australia; email: m.feischl@unsw.edu.au","","Society for Industrial and Applied Mathematics Publications","","","","","","00361429","","SJNAA","","English","SIAM J Numer Anal","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85028636669" +"Sayad M.; Potthoff M.","Sayad, Mohammad (55246618000); Potthoff, Michael (7003782242)","55246618000; 7003782242","Spin dynamics and relaxation in the classical-spin Kondo-impurity model beyond the Landau-Lifschitz-Gilbert equation","2015","New Journal of Physics","17","11","113058","","","","33","10.1088/1367-2630/17/11/113058","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84951310524&doi=10.1088%2f1367-2630%2f17%2f11%2f113058&partnerID=40&md5=9ce216a955d9c685a3fd0524a0d135b1","I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, Hamburg, D-20355, Germany","Sayad M., I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, Hamburg, D-20355, Germany; Potthoff M., I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstraße 9, Hamburg, D-20355, Germany","The real-time dynamics of a classical spin in an external magnetic field and local exchange coupled to an extended one-dimensional system of non-interacting conduction electrons is studied numerically. Retardation effects in the coupled electron-spin dynamics are shown to be the source for the relaxation of the spin in the magnetic field. Total energy and spin is conserved in the non-adiabaticrocess. Approaching the new local ground state is therefore accompanied by the emission of dispersive waveackets of excitations carrying energy and spin andropagating through the lattice with Fermi velocity. While the spin dynamics in the regime of strong exchange coupling J is rather complex and governed by an emergent new time scale, the motion of the spin for weak J is regular and qualitatively well described by the Landau-Lifschitz-Gilbert (LLG) equation. Quantitatively, however, the full quantum-classical hybrid dynamics differs from the LLG approach. This is understood as a breakdown of weak-couplingerturbation theory in J in the course of time. Furthermore, it is shown that the concept of the Gilbert dampingarameter is ill-defined for the case of a one-dimensional system. © 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.","electronic structure; hybrid models; LandauLifshitzGilbert equation; spin dynamics","Electronic structure; Electrospinning; Ground state; Magnetic field effects; Magnetic fields; Magnetic moments; Conduction electrons; Electron spin dynamics; External magnetic field; Hybrid model; LandauLifshitzGilbert equation; One-dimensional systems; Real-time dynamics; Retardation effect; Spin dynamics","","","","","","","Landau L.D., Lifshitz E.M., Phys. Z. Sow., 8, (1935); Gilbert T., Phys. Rev., 100, (1955); Gilbert T., IEEE Trans. Magn., 40, (2004); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Tatara G., Kohno H., Shibata J., Phys. Rep., 468, (2008); Skubic B., Hellsvik J., Nordstrom L., Eriksson O., J. Phys.: Condens. Matter, 20, 31, (2008); Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystemes, (2009); Fahnle M., Illg C., J. Phys.: Condens. Matter, 23, 49, (2011); Evans R.F.L., Fan W.J., Chureemart P., Ostler T.A., Ellis M.O.A., Chantrell R.W., J. Phys.: Condens. Matter, 26, 10, (2014); Ruderman M.A., Kittel C., Phys. Rev., 96, (1954); Kasuya T., Prog. Theor. Phys., 16, (1956); Yosida K., Phys. Rev., 106, (1957); Onoda M., Nagaosa N., Phys. Rev. Lett., 96, (2006); Bhattacharjee S., Nordstrom L., Fransson J., Phys. Rev. Lett., 108, (2012); Umetsu N., Miura D., Sakuma A., J. Appl. Phys., 111, (2012); Antropov V.P., Katsnelson M.I., Van Schilfgaarde M., Harmon B.N., Phys. Rev. Lett., 75, (1995); Antropov V.P., Katsnelson M.I., Harmon B.N., Van Schilfgaarde M., Kusnezov D., Phys. Rev., 54, (1996); Kunes J., Kambersky V., Phys. Rev., 65, (2002); Capelle K., Gyorffy B.L., Europhys. Lett., 61, 3, (2003); Ebert H., Mankovsky S., Kodderitzsch D., Kelly P.J., Phys. Rev. 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Lett., 93, (2004); Fetter A.L., Walecka J.D., Quantum Theory of Many-Particle Systems, (1971); Balzer M., Potthoff M., Phys. Rev., 83, (2011); Press W., Teukolsky S.A., Vetterling W.T., Flannery B., Numerical Recipes, (2007); Fransson J., Nanotechnology, 19, 28, (2008); Simanek E., Heinrich B., Phys. Rev., 67, (2003); Kambersky V., Phys. Rev., 76, (2007); Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 101, (2008); Mankovsky S., Kodderitzsch D., Woltersdorf G., Ebert H., Phys. Rev., 87, (2013); Thonig D., Henk J., New J. Phys., 16, 1, (2014); Ashcroft N.W., Mermin N.D., Solid State Physics, (1976)","M. Sayad; I. Institut für Theoretische Physik, Universität Hamburg, Hamburg, Jungiusstraße 9, D-20355, Germany; email: msayad@physnet.uni-hamburg.de","","Institute of Physics Publishing","","","","","","13672630","","","","English","New J. Phys.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-84951310524" +"Barangi M.; Erementchouk M.; Mazumder P.","Barangi, Mahmood (55585398400); Erementchouk, Mikhail (6603194008); Mazumder, Pinaki (35586470500)","55585398400; 6603194008; 35586470500","Towards developing a compact model for magnetization switching in straintronics magnetic random access memory devices","2016","Journal of Applied Physics","120","7","073901","","","","6","10.1063/1.4960952","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84982182615&doi=10.1063%2f1.4960952&partnerID=40&md5=1469c51b7c114fc658cd808dee1039b4","Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109-2121, MI, United States","Barangi M., Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109-2121, MI, United States; Erementchouk M., Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109-2121, MI, United States; Mazumder P., Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109-2121, MI, United States","Strain-mediated magnetization switching in a magnetic tunneling junction (MTJ) by exploiting a combination of piezoelectricity and magnetostriction has been proposed as an energy efficient alternative to spin transfer torque (STT) and field induced magnetization switching methods in MTJ-based magnetic random access memories (MRAM). Theoretical studies have shown the inherent advantages of strain-assisted switching, and the dynamic response of the magnetization has been modeled using the Landau-Lifshitz-Gilbert (LLG) equation. However, an attempt to use LLG for simulating dynamics of individual elements in large-scale simulations of multi-megabyte straintronics MRAM leads to extremely time-consuming calculations. Hence, a compact analytical solution, predicting the flipping delay of the magnetization vector in the nanomagnet under stress, combined with a liberal approximation of the LLG dynamics in the straintronics MTJ, can lead to a simplified model of the device suited for fast large-scale simulations of multi-megabyte straintronics MRAMs. In this work, a tensor-based approach is developed to study the dynamic behavior of the stressed nanomagnet. First, using the developed method, the effect of stress on the switching behavior of the magnetization is investigated to realize the margins between the underdamped and overdamped regimes. The latter helps the designer realize the oscillatory behavior of the magnetization when settling along the minor axis, and the dependency of oscillations on the stress level and the damping factor. Next, a theoretical model to predict the flipping delay of the magnetization vector is developed and tested against LLG-based numerical simulations to confirm the accuracy of findings. Lastly, the obtained delay is incorporated into the approximate solutions of the LLG dynamics, in order to create a compact model to liberally and quickly simulate the magnetization dynamics of the MTJ under stress. Using the developed delay equation, the efficiency of the straintronics switching over the STT method is highlighted by analytically investigating the energy-delay trade-off of both methodologies. © 2016 Author(s).","","Crystallography; Dynamics; Economic and social effects; Energy efficiency; Magnetic recording; Magnetic storage; Magnetization; MRAM devices; Nanomagnetics; Switching; Energy-delay trade-off; Landau-Lifshitz-Gilbert equations; Large scale simulations; Magnetic random access memory; Magnetic tunneling junctions; Magnetization dynamics; Magnetization switching; Oscillatory behaviors; Random access storage","","","","","National Science Foundation, NSF, (ECCS-1124714, PT106594-SC103006); Air Force Office of Scientific Research, AFOSR, (FA9550-12-1-0402)","This work was done partially under NSF NEB Grant No. ECCS-1124714 (PT106594-SC103006) and partially under AFOSR Grant No. FA9550-12-1-0402.","Borkar S., IEEE Micro, 19, (1999); Kuroda T., Proceedings of the Microprocessor and Nanotechnology Conference, (2001); Moore G., Proc. 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Lett., 83, (1999); Kronmuller H., Fahnle M., Micromagnetism and the Microstructure of Ferromagnetic Solids, (2003); Atulasimha J., Bandyopadhyay S., Appl. Phys. Lett., 97, (2010); Koch R., Katine J., Sun J., Phys. Rev. Lett., 92, (2004)","M. Barangi; Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, 48109-2121, United States; email: barangi@umich.edu","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-84982182615" +"Roy K.","Roy, Kuntal (14825673500)","14825673500","Ultra-low-energy electric field-induced magnetization switching in multiferroic heterostructures","2016","SPIN","6","3","1630001","","","","12","10.1142/S2010324716300012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85029324642&doi=10.1142%2fS2010324716300012&partnerID=40&md5=a0c866615ae33842d1a268b5b0f3d842","School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States","Roy K., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States","Electric field-induced magnetization switching in multiferroics is intriguing for both fundamental studies and potential technological applications. Here, we review the recent developments on electric field-induced magnetization switching in multiferroic heterostructures. Particularly, we study the dynamics of magnetization switching between the two stable states in a shape-anisotropic single-domain nanomagnet using stochastic Landau-Lifshitz-Gilbert (LLG) equation in the presence of thermal fluctuations. For magnetostrictive nanomagnets in strain-coupled multiferroic composites, such study of magnetization dynamics, contrary to steady-state scenario, revealed intriguing new phenomena on binary switching mechanism. While the traditional method of binary switching requires to tilt the potential profile to the desired state of switching, we show that no such tilting is necessary to switch successfully since the magnetization's excursion out of magnet's plane can generate a built-in asymmetry during switching. We also study the switching dynamics in multiferroic heterostructures having magnetoelectric coupling at the interface and magnetic exchange coupling that can facilitate to maintain the direction of switching with the polarity of the applied electric field. We calculate the performance metrics like switching delay and energy dissipation during switching while simulating LLG dynamics. The performance metrics turn out to be very encouraging for potential technological applications. © World Scientific Publishing Company","Electric field-induced magnetization switching; Energy-effcient design; Multiferroics; Nanoelectronics; Spintronics; Straintronics","","","","","","","","Landau L.D., Lifshitz E.M., Electrodynamics of Continuous Media, (1960); Schmid H., Ferroelectrics, 162, (1994); Eerenstein W., Mathur N.D., Scott J.F., Nature, 442, (2006); Lawes G., Srinivasan G., J. Phys. D: Appl. 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Pte Ltd","","","","","","20103247","","","","English","SPIN","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85029324642" +"Hahn M.B.","Hahn, Marc Benjamin (56996724600)","56996724600","Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau–Lifshitz equation","2019","Journal of Physics Communications","3","7","075009","","","","25","10.1088/2399-6528/ab31e6","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85078603123&doi=10.1088%2f2399-6528%2fab31e6&partnerID=40&md5=6075529030d09dac93bd3a984ba2e3af","Institut für Experimentalphysik, Freie Universität Berlin, Berlin, D-14195, Germany; Bundesanstalt für Materialforschung und-prüfung, Berlin, D-12205, Germany","Hahn M.B., Institut für Experimentalphysik, Freie Universität Berlin, Berlin, D-14195, Germany, Bundesanstalt für Materialforschung und-prüfung, Berlin, D-12205, Germany","The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau–Lifshitz (LL) or Landau–Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31 ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model. © 2019 The Author(s). Published by IOP Publishing Ltd.","Curie temperature; Landau-Lifshitz-Gilbert equation; Micromagnetism; OOMMF; Stochastic Landau-Lifshitz equation","","","","","","","","Landau L., Lifschitz E., Phys. Zeitsch. Der Sow., 8, (1935); Atxitia U., Hinzke D., Nowak U., J. Phys. D: Appl. Phys., 50, (2017); Gilbert T., IEEE Trans. Magn., 40, (2004); Garanin D.A., Phys. Rev. B, 55, (1997); Lopez-Diaz L., Aurelio D., Torres L., Martinez E., Hernandez-Lopez M.A., Gomez J., Alejos O., Carpentieri M., Finocchio G., Consolo G., J. Phys. D: Appl. Phys., 45, (2012); Kumar D., Adeyeye A.O., J. Phys. D: Appl. Phys., 50, (2017); Wiele B.V., Laurson L., Durin G., Eur. Phys. J. B, 86, (2013); Vogler C., Abert C., Bruckner F., Suess D., Praetorius D., J. Appl. 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Commun.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85078603123" +"Them K.","Them, Kolja (55578434400)","55578434400","On magnetic dipole-dipole interactions of nanoparticles in magnetic particle imaging","2017","Physics in Medicine and Biology","62","14","","5623","5639","16","23","10.1088/1361-6560/aa70ca","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85021687621&doi=10.1088%2f1361-6560%2faa70ca&partnerID=40&md5=74f3b8bcd5e0e87e7648c3803a9a0e7f","Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, Hamburg, 20246, Germany; Institute for Biomedical Imaging, Hamburg University of Technology, Schwarzenbergstrasse 95, Hamburg, 21073, Germany","Them K., Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, Hamburg, 20246, Germany, Institute for Biomedical Imaging, Hamburg University of Technology, Schwarzenbergstrasse 95, Hamburg, 21073, Germany","Magnetic dipole-dipole (MDD) interactions between iron oxide nanoparticles can influence the sensitivity, image resolution and quantification of magnetic particle imaging (MPI). For the first time, the Landau-Lifshitz-Gilbert equation (LLG) for MDD interactions has been solved to investigate the effect of MDD interactions on the MPI spectrum. It was found that at concentrations above 39 mmol(Fe) l-1, MDD interactions significantly influence MPI spectra. This influence increases with increasing harmonics, which means first harmonics should be preferred for iron quantification. Since ≈1018 particles are neglected in the LLG compared to in an MPI experiment, the calculated limit below which MDD interactions can be neglected is only a bound. The true limit is therefore below the calculated limit of 39 mmol(Fe) l-1, because all other neglected particles also contribute to deviations in the MPI spectra via MDD interactions. Therefore, a quantum mechanical bound on the influence of MDD interactions is calculated, including up to 1015 particles. Analysis of the bound as a function of the particle number provides a valuable insight into the influence of the large number of particles neglected in numerical simulations. Both results are compared with concentrations in biomedical MPI experiments. We conclude that the standard approximation of an absence of MDD interactions in MPI experiments must be handled more carefully. Our method of incorporating MDD interactions into the LLG can be easily implemented as part of model-based reconstruction to increase the sensitivity, image resolution and quantitative tracer detection during MPI. © 2017 Institute of Physics and Engineering in Medicine.","Landau-Lifshitz-Gilbert equation; magnetic dipole-dipole interactions; magnetic nanoparticles; magnetic particle imaging","Ferric Compounds; Image Processing, Computer-Assisted; Magnets; Nanoparticles; Physical Phenomena; Tomography; Dipole moment; Electric dipole moments; Image resolution; Magnetism; Nanomagnetics; Nanoparticles; Quantum theory; ferric ion; ferric oxide; nanoparticle; Iron oxide nanoparticle; Landau-Lifshitz-Gilbert equations; Magnetic dipole-dipole interaction; Magnetic nano-particles; Magnetic particle imaging; Model based reconstruction; Particle numbers; Quantum mechanical; chemistry; image processing; magnet; physical phenomena; procedures; tomography; Magnetic bubbles","","ferric ion, 20074-52-6; ferric oxide, 1309-37-1, 56449-54-8; Ferric Compounds, ; ferric oxide, ","","","","","Arami H., Krishnan K.M., Intracellular performance of tailored nanoparticle tracers in magnetic particle imaging, J. 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Imaging, 32, pp. 1565-1575, (2013); Lwa N., Radon P., Kosch O., Wiekhorst F., Concentration dependent mpi tracer performance, Int. J. Mag. Part. Imaging, 2, (2016); Rahmer J., Antonelli A., Sfara C., Tiemann B., Gleich B., Magnani M., Weizenecker J., Borgert J., Nanoparticle encapsulation in red blood cells enables blood-pool magnetic particle imaging hours after injection, Phys. Med. Biol., 58, 12, (2013); Rogge H., Erbe M., Buzug T., Ldtke-Buzug K., Simulation of the magnetization dynamics of diluted ferrofluids in medical applications, Biomed. Tech. Biomed. Eng., 6, pp. 601-609, (2013); Shah S.A., Ferguson R.M., Krishnan K.M., Slew-rate dependence of tracer magnetization response in magnetic particle imaging, J. Appl. Phys., 116, (2014); Knopp T., Them M.K., Gdaniec N., Joint reconstruction of non-overlapping magnetic particle imaging focus-field data, Phys. Med. Biol., 60, 8, (2015); Thapa D., Palkar V., Kurup M., Malik S., Properties of magnetite nanoparticles synthesized through a novel chemical route, Mater. Lett., 58, pp. 2692-2694, (2004); Them K., Dissertation, (2014); Them K., Towards experimental tests and applications of lieb-robinson bounds, Phys. Rev., 89, (2014); Them K., Salamon J., Szwargulski P., Sequeira S., Kaul M.G., Lange C., Ittrich H., Knopp T., Increasing the sensitivity for stem cell monitoring in system-function based magnetic particle imaging, Phys. Med. Biol., 61, 9, (2016); Them K., Stapelfeldt T., Vedmedenko E.Y., Wiesendanger R., Non-equilibrium finite temperature dynamics of magnetic quantum systems: Applications to spin-polarized scanning tunneling microscopy, New J. Phys., 15, 1, (2013); Them K., Vedmedenko E.Y., Fredenhagen K., Wiesendanger R., Bounds on expectation values of quantum subsystems and perturbation theory, J. Phys. A: Math. Theor., 48, (2015); Weizenecker J., Et al., Particle dynamics of mono-domain particles in magnetic particle imaging, Magn. Nanoparticles: Part. Sci. Imaging Technol. Clin. Appl., (2010); Weizenecker J., Gleich B., Rahmer J., Dahnke H., Borgert J., Three-dimensional real-time in vivo magnetic particle imaging, Phys. Med. Biol., 54, 5, (2009)","K. Them; Section for Biomedical Imaging, University Medical Center Hamburg-Eppendorf, Hamburg, Martinistrasse 52, 20246, Germany; email: k.them@uke.de","","Institute of Physics Publishing","","","","","","00319155","","PHMBA","28467324","English","Phys. Med. Biol.","Article","Final","","Scopus","2-s2.0-85021687621" +"Ayouch C.; Essoufi E.-H.; Tilioua M.","Ayouch, Chahid (57189905298); Essoufi, El-Hassan (6504162169); Tilioua, Mouhcine (6507877823)","57189905298; 6504162169; 6507877823","On a model of magnetization dynamics with vertical spin stiffness","2016","Boundary Value Problems","2016","1","110","","","","4","10.1186/s13661-016-0618-3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84975842871&doi=10.1186%2fs13661-016-0618-3&partnerID=40&md5=74ba1ba6824da1510b78be8459caf1be","Laboratoire MISI, FST Settat, Univ. Hassan I, Settat, 26000, Morocco; M2I Laboratory, MAMCS Group, FST Errachidia, Univ. Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","Ayouch C., Laboratoire MISI, FST Settat, Univ. Hassan I, Settat, 26000, Morocco; Essoufi E.-H., Laboratoire MISI, FST Settat, Univ. Hassan I, Settat, 26000, Morocco; Tilioua M., M2I Laboratory, MAMCS Group, FST Errachidia, Univ. Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","We consider a mathematical model describing magnetization dynamics with vertical spin stiffness. The model consists of a modified form of the Landau-Lifshitz-Gilbert equation for the evolution of the magnetization vector in a rigid ferromagnet. The modification lies in the presence in the effective field of a nonlinear term describing vertical spin stiffness. We prove the global existence of weak solutions to the model by using the Faedo-Galerkin method and discuss the limit of the obtained solutions as the vertical spin stiffness parameter tends to zero. © 2016, Ayouch et al.","Faedo-Galerkin method; ferromagnetic materials; global existence; LLG equation; vertical spin stiffness","","","","","","Providence Health Care, PHC; Ministry of Higher Education and Scientific Research, MHESR; Ministère des Affaires Etrangères","The research is supported by the PHC Volubilis program MA/14/301 ‘Elaboration et analyse de modèles asymptotiques en micro-magnétisme, magnéto-élasticité et électro-élasticité’ with joint financial support from the French Ministry of Foreign Affairs and the Moroccan Ministry of Higher Education and Scientific Research. ","Hubert A., Schafer R., Magnetic Domains: The Analysis of Magnetic Microstructures, (1998); Tserkovnyak Y., Brataas A., Bauer G.E.W., Halperin B.I., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Rev. Mod. Phys., 77, pp. 1375-1421, (2005); Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, pp. 190-194, (2008); Shen K., Tatara G., Wu M.W., Existence of vertical spin stiffness in Landau-Lifshitz-Gilbert equation in ferromagnetic semiconductors, Phys. Rev. B, 83, (2011); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev., 48, pp. 439-483, (2006); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and non uniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Jpn. J. Appl. Math., 2, pp. 69-84, (1985); Carbou G., Fabrie P., Time average in micromagnetism, J. Differ. Equ., 147, pp. 383-409, (1998); Bertsch M., Podio-Guidugli P., Valente V., On the dynamics of deformable ferromagnets. I. Global weak solutions for soft ferromagnets at rest, Ann. Mat. Pura Appl. (4), 179, pp. 331-360, (2001); Podio-Guidugli P., Valente V., Existence of global-in-time weak solutions to a modified Gilbert equation, Nonlinear Anal., 47, pp. 147-158, (2001); Roubicek T., Tomassetti G., Zanini C., The Gilbert equation with dry-friction type damping, J. Math. Anal. Appl., 355, 2, pp. 453-468, (2009); Hadda M., Tilioua M., On magnetization dynamics with inertial effects, J. Eng. Math., 88, pp. 197-206, (2014); Tilioua M., Current-induced magnetization dynamics. Global existence of weak solutions, J. Math. Anal. Appl., 373, pp. 635-642, (2011); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci., 16, pp. 299-319, (2006); Bartels S., Ko J., Prohl A., Numerical approximation of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comput., 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 44, pp. 1405-1419, (2006); Lions J.L., Quelques Méthodes de Résolution des Problèmes aux Limites Non Linéaires, (1969)","M. Tilioua; M2I Laboratory, MAMCS Group, FST Errachidia, Univ. Moulay Ismaïl, Errachidia, P.O. Box 509, Boutalamine, 52000, Morocco; email: m.tilioua@fste.umi.ac.ma","","Springer International Publishing","","","","","","16872762","","","","English","Boundary Value Probl.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-84975842871" +"Nguyen Q.; Zaghloul A.I.","Nguyen, Quang (25632831300); Zaghloul, Amir I. (7007059212)","25632831300; 7007059212","Susceptibility of nanoparticles studied by landau-lifshitz-gilbert and snoek's equations","2019","2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019 - Proceedings","","","8888631","1299","1300","1","2","10.1109/APUSNCURSINRSM.2019.8888631","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85075260164&doi=10.1109%2fAPUSNCURSINRSM.2019.8888631&partnerID=40&md5=22afb22d26d54c2e72161bbe5daf8ce3","US Army Research Laboratory, Adelphi, 20783, MD, United States","Nguyen Q., US Army Research Laboratory, Adelphi, 20783, MD, United States; Zaghloul A.I., US Army Research Laboratory, Adelphi, 20783, MD, United States","Snoek's law is a well-known theory used to predict magnetic properties of bulk ferromagnetic material. Landau-Lifshitz-Gilber (LLG) equations are differential equations used to describe the precessional motion of magnetization in magnetic materials. In this paper, we focus on magnetic nanoparticles and study the relationship between LLG equations and Snoek's law in seeking high permeability at high frequencies in magnetic materials. The susceptibility/permeability calculations of cobalt nanoparticles with different shapes are carried out analytically. Micromagnetic software package, Object Oriented MicroMagnetic Framework (OOMMF) software package, has been used to validate the results. © 2019 IEEE.","Cobalt nanoparticle; Landau-Lifshitz-Gilbert equations; Micromagnetic simulation; OOMMF; Snoek's law.","","","","","","","","Mosallaei H., Sarabandi K., Magneto-dielectrics in electromagnetics: Concept and applications, IEEETrans.AntennasPropag., AP-52, pp. 1558-1567, (2004); Snoek J.L., Dispersion and absorption in magnetic ferrites at frequencies above one mc/s, Physica., 14, 4, pp. 207-217, (1948); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjet., 8, pp. 153-169, (1935); Ramprasad R., Zurcher P., Petras M., Miller M., Renaud P., Magnetic properties of metallic ferromagnetic nanoparticle composites, Journal of Applied Physics, 96, 1, pp. 519-529, (2004); Donahue M.J., Porter D.G., OOMMF User's Guide, Version 2.0; Nguyen Q.M., Zaghloul A.I., Extension of snoek's law to higher rf frequencies by controlling nanomagnetic particle parameters, EMTS 2019, (2019); Kittel C., On the theory of ferromagnetic resonance absorption, Physical Review, 73, pp. 155-161, (1948)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society (APS); The Institute of Electrical and Electronics Engineers (IEEE)","2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, APSURSI 2019","7 July 2019 through 12 July 2019","Atlanta","153911","","978-172810692-2","","","English","IEEE Int. Symp. Antennas Propag. USNC-URSI Radio Sci. Meet., APSURSI - Proc.","Conference paper","Final","","Scopus","2-s2.0-85075260164" +"Ávila-Crisóstomo C.E.; Sánchez-Mora E.; Garcia-Vazquez V.; Pérez-Rodríguez F.","Ávila-Crisóstomo, C.E. (57202575612); Sánchez-Mora, E. (15926183400); Garcia-Vazquez, V. (7801667162); Pérez-Rodríguez, F. (7004480201)","57202575612; 15926183400; 7801667162; 7004480201","Magnetic response of Fe nanoparticles embedded in artificial SiO2 opals","2018","Journal of Magnetism and Magnetic Materials","465","","","252","259","7","5","10.1016/j.jmmm.2018.05.087","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85048748485&doi=10.1016%2fj.jmmm.2018.05.087&partnerID=40&md5=0b6bbcecfa77cdc00bae1fe392f6cc73","Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48, Puebla, 72570, Pue., Mexico","Ávila-Crisóstomo C.E., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48, Puebla, 72570, Pue., Mexico; Sánchez-Mora E., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48, Puebla, 72570, Pue., Mexico; Garcia-Vazquez V., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48, Puebla, 72570, Pue., Mexico; Pérez-Rodríguez F., Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apdo. Post. J-48, Puebla, 72570, Pue., Mexico","Applying the Stöber method, silica spheres were obtained and arranged in an fcc lattice. Metallic Fe was introduced into the opal voids. Magnetization curves of the synthesized metallic nanoparticles and of the artificial opals with infiltrated nanoparticles were measured by using the vibrating sample magnetometry (VSM) technique with an applied magnetic field oriented along the [1 1 1] direction of the opal matrix. Nonlinear Landau-Lifshitz-Gilbert (LLG) equation was numerically solved, in order to reproduce the experimental results. In solving LLG equation we have used Ewald summations to take into account the dipolar interaction between the spatially arranged magnetic nanoparticles. The theory reproduces the general features of the measured magnetization curves. In particular, the S-like shape of the magnetization curves produced by the ferromagnetic response of Fe nanoparticles and the diamagnetic one of the SiO2 opal matrix is well described. The observed small areas of the magnetization hysteresis loops are explained as a consequence of the random distribution of the magnetic anisotropy axes of the Fe nanoparticles. The effect of the dipolar interaction between the magnetic nanoparticles is predicted to be important at magnitudes of the external applied field, larger than the coercive magnetic field. © 2018 Elsevier B.V.","Ferromagnetism; Nanocomposite; Nanoparticles; Opal","Ferromagnetism; Iron; Magnetic anisotropy; Magnetic fields; Magnetic materials; Magnetization; Magnetometry; Nanocomposites; Nanoparticles; Nonlinear equations; Silica; Silicate minerals; Synthesis (chemical); Applied magnetic fields; Ferromagnetic response; Landau-Lifshitz-Gilbert equations; Magnetic nano-particles; Magnetization hysteresis-loop; Metallic nanoparticles; Opal; Vibrating sample magnetometry; Nanomagnetics","","","","","PRODEP; VIEP-BUAP","This work was partially supported by PRODEP , PFCE , and VIEP-BUAP . We thank Dr. N. Rutilo Silva for his assistance in obtaining Scanning Electron Microscopy micrographs. ","Sanders J.V., Colour of precious opal, Nature, 4964, pp. 1151-1153, (1964); Stober W., Fink A., Bohn E., Controlled growth of monodisperse silica spheres in the micron size range, J. Colloid Interface Sci., 26, pp. 62-69, (1968); Xia Y., Gates B., Yin Y., Lu Y., Monodispersed colloidal spheres: old materials with new applications, Adv. Mater., 12, 10, pp. 693-713, (2000); Trofimova E.Y., Et al., Monodisperse spherical mesoporous silica particles: fast synthesis procedure and fabrication of photonic-crystal films, Nanotechnology, 24, pp. 1-11, (2013); Mayoral R., Et al., 3d long-range orderingrange ordering in an SiO2 submicrometer-sphere sintered superstructure, Adv. Matter., 9, 3, pp. 257-260, (1997); Tan C.G., Bowen B.D., Epstein N., Production of monodisperse colloidal silica spheres: Effect of temperature, J. Colloid Interface Sci., 118, 1, pp. 290-293, (1987); Cheng B., Et al., More direct evidence of the fcc arrangement for artificial opal, Opt. 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Mater., 322, pp. 1494-1496, (2010); Cong H., Yu B., Fabrication of superparamagnetic macroporous Fe3O4 and its derivates using colloidal crystals as templates, J. Colloid Interface Sci., 353, pp. 131-136, (2011); Skuja L., Et al., Infrared photoluminescence of preexisting or irradiation-induced interstitial oxygen molecules in glassy SiO2 and α-quartz, Phys. Rev. B, 58, 21, pp. 14298-14304, (1998); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. der Sow., 8, pp. 153-169, (1935); Dudek M.R., Guskos N., Grabiec B., Maryniak M., Magnetization dynamics in Landau–Lifshitz–Gilbert formulation. FMR experiment modeling, J. Non-Cryst. Solids, 354, pp. 4146-4150, (2008); Jung S., Ketterson J.B., Chandrasekhar V., Micromagnetic calculations of ferromagnetic resonance in submicron ferromagnetic particles, Phys. Rev. B, 66, pp. 1-4, (2002); Miles J.J., Middleton B.K., The role of microstructure in micromagnetic models of longitudinal thin film magnetic media, IEEE Trans. Magn., 26, 5, pp. 2137-2139, (1990); Shampine L.F., Witt A., A simple step size selection algorithm for ode codes, J. Comput. Appl. Math., 58, pp. 345-354, (1995); Scott G.G., A precise mechanical measurement of the gyromagnetic ratio of iron, Phys. Rev., 82, 4, pp. 542-547, (1951)","C.E. Ávila-Crisóstomo; Instituto de Física, Benemérita Universidad Autónoma de Puebla, Puebla, Apdo. Post. J-48, 72570, Mexico; email: cavila@ifuap.buap.mx","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85048748485" +"Yao Z.; Wang Y.E.","Yao, Zhi (56380891100); Wang, Yuanxun Ethan (35194804700)","56380891100; 35194804700","3D unconditionally stable FDTD modeling of micromagnetics and electrodynamics","2017","IEEE MTT-S International Microwave Symposium Digest","","","8058902","12","15","3","6","10.1109/MWSYM.2017.8058902","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85032509097&doi=10.1109%2fMWSYM.2017.8058902&partnerID=40&md5=186e06525a23271f0f86e8f1c1147e45","University of California, Los Angeles, United States","Yao Z., University of California, Los Angeles, United States; Wang Y.E., University of California, Los Angeles, United States","A rigorous yet computationally efficient three-dimensional numerical method has been proposed based on modified alternating-direction-implicit (ADI) finite difference time domain methods (FDTD) and it has the capability of modeling the eccentric property of magnetic material being anisotropic, dispersive or nonlinear. The proposed algorithm solves Maxwell's equations and LLG equations simultaneously, requiring only tridiagonal matrix inversion as in ADI FDTD. The accuracy of the modeling has been validated by the simulated dispersive permeability of a continuous ferrite film with a 1.5 μm-thickness, using a time-step size 104 times larger than the Courant limit. The permeability agrees with the theoretical prediction and magneto-static spin wave modes are observed. Moreover, electric current sheet radiators close to perfect electrical conductors loaded with 2 μm-thick ferrite films are simulated, which exhibit a radiation efficiency 20dB higher than conventional dipole antennas on the same scale. © 2017 IEEE.","Electrically small antenna; Ferrimagnetic films; Finite difference time domain methods; Multiphysics; Unconditionally stable methods","Antennas; Dipole antennas; Dispersion (waves); Ferrite; Finite difference time domain method; Magnetic materials; Matrix algebra; Maxwell equations; Numerical methods; Spin waves; Alternating direction implicit; Computationally efficient; Dispersive permeability; Electrically small antennas; Ferrimagnetic films; Multi-physics; Perfect electrical conductor; Unconditionally stable methods; Time domain analysis","","","","","U.S. National Science Foundation, (1160504)","This work is sponsored by U.S. National Science Foundation through TANMS (Translational Applications of Na-noscale Multiferroic Systems) Engineering Research Center under award #1160504.","Wu M., Hoffmann A., Et al., Solid State Physics: Recent Advances in Magnetic Insulators-From Spintronics to Microwave Applications, (2013); Yao Z., Wang Y.E., Keller S., Carman G.P., Bulk acoustic wavemediated multiferroic antennas: Architecture and performance bound, Antennas and Propagation, IEEE Transactions on, 63, pp. 3335-3344, (2015); Taflove A., Hagness S.C., Computational Electrodynamics: The Finite-difference Time-domain Method, (2000); Zheng F., Chen Z., Zhang J., Toward the development of a threedimensional unconditionally stable finite-difference time-domain method, IEEE Trans. Microw. Theory Techn, 48, 9, pp. 1550-1558, (2000); Namiki T., A new FDTD algorithm based on alternating-direction implicit method, IEEE Trans. Microw. Theory Techn, 47, 10, pp. 2003-2007, (1999); Staker S.W., Holloway C.L., Bhobe A.U., Piket-May M., Alternating-direction implicit (ADI) formulation of the finite-difference timedomain (FDTD) method: Algorithm and material dispersion implementation, IEEE Trans. Electromagn. Compat, 45, 2, pp. 156-166, (2003); Chung Y., Sarkar T.K., Jung B.H., Salazar-Palma M., An unconditionally stable scheme for the finite-difference time-domain method, IEEE Trans. Microw. Theory Techn, 51, 3, pp. 697-704, (2003); Sun C., Trueman C.W., Unconditionally stable crank-nicolson scheme for solving two-dimensional maxwell's equations, Electron. Lett, 39, 7, pp. 595-597, (2003); Tan E.L., Fundamental schemes for efficient unconditionally stable implicit finite-difference time-domain methods, IEEE Trans. Antennas Propag, 56, 1, pp. 170-177, (2008); Gaffar M., Jiao D., An explicit and unconditionally stable FDTD method for electromagnetic analysis, IEEE Trans. Microw. Theory Tech, 62, 11, pp. 2538-2550, (2014); Pereda J.A., Et al., FDTD analysis of magnetized ferrites: Application to the calculation of dispersion characteristics of ferrite-loaded waveguides, IEEE Trans. Microw. Theory Tech, 43, 2, pp. 350-357, (1995); Ikonen P.M.T., Rozanov K.N., Osipov A.V., Alitalo P., Tretyakov S.A., Magnetodielectric substrates in antenna miniaturization: Potential and limitations, IEEE Trans. Antennas Propag, 54, 11, pp. 3391-3399, (2006)","","","Institute of Electrical and Electronics Engineers Inc.","","2017 IEEE MTT-S International Microwave Symposium, IMS 2017","4 June 2017 through 9 June 2017","Honololu","131000","0149645X","978-150906360-4","IMIDD","","English","IEEE MTT S Int Microwave Symp Dig","Conference paper","Final","","Scopus","2-s2.0-85032509097" +"Srinivasan S.; Diep V.; Behin-Aein B.; Sarkar A.; Datta S.","Srinivasan, Srikant (57201926000); Diep, Vinh (55931861100); Behin-Aein, Behtash (26433087000); Sarkar, Angik (57225752746); Datta, Supriyo (57206956172)","57201926000; 55931861100; 26433087000; 57225752746; 57206956172","Modeling multi-magnet networks interacting via spin currents","2015","Handbook of Spintronics","","","","1281","1335","54","5","10.1007/978-94-007-6892-5_46","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84956686308&doi=10.1007%2f978-94-007-6892-5_46&partnerID=40&md5=d4a6db1e1ae5bcda21a34a7f55e00d33","School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States; Iowa State University, Ames, IN, United States; School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States; Global Foundries, Milpitas, CA, United States","Srinivasan S., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States, Iowa State University, Ames, IN, United States; Diep V., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States; Behin-Aein B., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States, Global Foundries, Milpitas, CA, United States; Sarkar A., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States; Datta S., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, United States","The significant experimental advances of the last few decades in dealing with the interaction of spin currents and nanomagnets, at the device level, have allowed envisioning a broad class of devices that propose to implement information processing using spin currents and nanomagnets. To analyze such spin-magnet logic circuits, in general, we have developed a coupled spin-transport/magnetization- dynamics simulation framework that could be broadly applicable to various classes of spin-valve/spin-torque devices. Indeed, the primary purpose of this chapter is to describe in detail the overall approach we have developed to include a description of spin transport coupled with magnetization dynamics and to show how it was benchmarked against available data on experiments. We address noncollinear spin transport in section ""Circuit Representation of Spin Transport"" using a lumped ""four-component spin-circuit formalism"" that describes the interaction of noncollinear magnets (required for modeling spin torque), by computing four-component currents and voltages at every node of a ""circuit."" For modeling the magnetization dynamics, we use the standard Landau-Lifshitz-Gilbert (LLG) equation with the Slonczewski and the field-like terms included for spin torque. Section ""A Coupled Spin-Transport/Magnetization-Dynamics Simulator"" describes how this LLG model is coupled with the spin-transport model to analyze spin-torque experiments and spin-magnet circuits in general. We include MATLAB codes in the Additional Information to facilitate a ""hands-on"" understanding of our model and hope it will enable interested readers to conveniently analyze their own experiments, develop a deeper insight into spin-magnet circuits, or come up with their own creative designs. © Springer Science+Business Media Dordrecht 2016. All rights reserved.","","Band structure; Computation theory; Computer circuits; Coupled circuits; Dynamics; Electric network analysis; Magnetization; Magnets; MATLAB; Nanomagnetics; Torque; Creative design; Currents and voltages; Dynamics simulation; Landau-Lifshitz-Gilbert equations; Magnet network; Magnetization dynamics; Noncollinear magnets; Spin transport; Spin dynamics","","","","","","","Welser J.J., Et al., The quest for the next information processing technology, J Nanoparticle Res, 10, 1, pp. 1-10, (2008); Theis T.N., Solomon P.M., It's time to reinvent the transistor!, Science, 327, 5973, pp. 1600-1601, (2010); Behin-Aein B., Et al., Proposal for an all-spin logic device with built-in memory, Nat Nanotechnol, 5, 4, pp. 266-270, (2010); Dery H., Et al., Spin-based logic in semiconductors for reconfigurable large-scale circuits, Nature, 447, 7144, pp. 573-576, (2007); Wang J.G., Meng H., Wang J.P., Programmable spintronics logic device based on a magnetic tunnel junction element, J Appl Phys, 97, 10, (2005); Huang B.Q., Monsma D.J., Appelbaum I., Experimental realization of a silicon spin fieldeffect transistor, Appl Phys Lett, 91, 7, (2007); Johnson M., Silsbee R.H., Interfacial charge-spin coupling - injection and detection of spin magnetization in metals, Phys Rev Lett, 55, 17, pp. 1790-1793, (1985); Jedema F.J., Filip A.T., van Wees B.J., Electrical spin injection and accumulation at room temperature in an all-metal mesoscopic spin valve, Nature, 410, 6826, pp. 345-348, (2001); Huang B., Monsma D.J., Appelbaum I., Coherent spin transport through a 350 micron thick silicon wafer, Phys Rev Lett, 99, 17, (2007); Tsoi M.et al., Et al., Excitation of a magnetic multilayer by an electric current, Phys Rev Lett, 80, 19, pp. 4281-4284, (1998); Katine J.A., Et al., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, Phys Rev Lett, 84, 14, pp. 3149-3152, (2000); Grollier J., Et al., Spin-polarized current induced switching in Co/Cu/Co pillars, Appl Phys Lett, 78, 23, pp. 3663-3665, (2001); Srinivasan S., Et al., All-spin logic device with inbuilt nonreciprocity, IEEE Trans Magn, 47, 10, pp. 4026-4032, (2011); Behin-Aein B., Et al., Switching energy-delay of all spin logic devices, Appl Phys Lett, 98, 12, (2011); Yang T., Kimura T., Otani Y., Giant spin-accumulation signal and pure spin-currentinduced reversible magnetization switching, Nat Phys, 4, 11, pp. 851-854, (2008); Zou H., Ji Y., Temperature evolution of spin-transfer switching in nonlocal spin valves with dipolar coupling, J Magn Magn Mater, 323, 20, pp. 2448-2452, (2011); Datta S., Salahuddin S., Behin-Aein B., Non-volatile spin switch for Boolean and non-Boolean logic, Appl Phys Lett, 101, 25, (2012); Srinivasan S., Et al., Unidirectional information transfer with cascaded all spin logic devices: a ring oscillator, Device research conference (DRC), (2011); Sarkar A., Et al., Modeling all spin logic: multi-magnet networks interacting via spin currents, 2011 I.E. international electron devices meeting (IEDM), (2011); Sharad M., Et al., Ultra low energy analog image processing using spin based neurons, Nanoscale Architectures (NANOARCH), 2012 IEEE/ACM international symposium on, (2012); Brataas A., Bauer G.E.W., Kelly P.J., Non-collinear magnetoelectronics, Phys Rep-Rev Section Phys Lett, 427, 4, pp. 157-255, (2006); Kovalev A.A., Brataas A., Bauer G.E.W., Spin transfer in diffusive ferromagnet-normal metal systems with spin-flip scattering, Phys Rev B, 66, 22, (2002); Xia K., Et al., Spin torques in ferromagnetic/normal-metal structures, Phys Rev B, 65, 22, (2002); Zainuddin A.N.M., Et al., Magnetoresistance of lateral semiconductor spin valves, J Appl Phys, 108, 12, (2010); Augustine C., Et al., Numerical analysis of domain wall propagation for dense memory array, Electron devices meeting (IEDM); Takahashi S., Maekawa S., Spin injection and detection in magnetic nanostructures, Physical Review B, 67, 5; Slonczewski J.C., Current-driven excitation of magnetic multilayers, J Magn Magn Mater, 159, 1-2, pp. L1-L7, (1996); Datta S., Quantum transport: atom to transistor, (2005); Valet T., Fert A., Theory of the perpendicular magnetoresistance in magnetic multilayers, Phys Rev B, 48, 10, pp. 7099-7113, (1993); Johnson M., Silsbee R.H., Thermodynamic analysis of interfacial transport and of the thermomagnetoelectric system, Phys Rev B, 35, 10, pp. 4959-4972, (1987); Fert A., Campbell I.A., 2-current conduction in nickel, Phys Rev Lett, 21, 16, (1968); Mott N., The electrical conductivity of transition metals, Proc R Soc Lond Ser A Math Phys Sci, 153, 880, pp. 699-717, (1936); Julliere M., Tunneling between ferromagnetic-films, Phys Lett A, 54, 3, pp. 225-226, (1975); Maekawa S., Gafvert U., Electron-tunneling between ferromagnetic-films, IEEE Trans Magn, 18, 2, pp. 707-708, (1982); Moodera J.S., Et al., Large magnetoresistance at room-temperature in ferromagnetic thinfilm tunnel-junctions, Phys Rev Lett, 74, 16, pp. 3273-3276, (1995); Mavropoulos P., Papanikolaou N., Dederichs P.H., Complex band structure and tunneling through ferromagnet/insulator/ferromagnet junctions, Phys Rev Lett, 85, 5, pp. 1088-1091, (2000); Butler W.H., Et al., Spin-dependent tunneling conductance of Fe vertical bar MgO vertical bar Fe sandwiches, Phys Rev B, 63, 5, pp. 54416-54411, (2001); Schmidt G., Et al., Fundamental obstacle for electrical spin injection from a ferromagnetic metal into a diffusive semiconductor, Phys Rev B, 62, 8, pp. R4790-R4793, (2000); Fert A., Jaffres H., Conditions for efficient spin injection from a ferromagnetic metal into a semiconductor, Phys Rev B, 64, 18, (2001); Fert A., Et al., Semiconductors between spin-polarized sources and drains, IEEE Trans Electron Devices, 54, 5, pp. 921-932, (2007); Datta D., Et al., Voltage asymmetry of spin-transfer torques, IEEE Trans Nanotechnol, 11, 2, pp. 261-272, (2012); Kovalev A.A., Bauer G.E.W., Brataas A., Perpendicular spin valves with ultrathin ferromagnetic layers: magnetoelectronic circuit investigation of finite-size effects, Phys Rev B, 73, 5, (2006); Sun J.Z., Spin-current interaction with a monodomain magnetic body: a model study, Phys Rev B, 62, 1, pp. 570-578, (2000); Augustine C., Panagopoulos G., Behin-Aein B., Srinivasan S., Sarkar A., Roy K., Low-power functionality enhanced computation architecture using spin-based devices, Nanoscale architectures (NANOARCH), pp. 129-136, (2011); Manipatruni S., Nikonov D.E., Young I.A., Modeling and design of spintronic integrated circuits, Circuits Syst I Regul Papers, IEEE Trans, 59, 12, pp. 2801-2814, (2012); Sharad M., Augustine C., Panagopoulos G., Roy K., Spin-based neuron model with domain-wall magnets as synapse, Nanotechnol, IEEE Trans, 11, 4, pp. 843-853, (2012); Bonhomme P., Manipatruni S., Iraei R.M., Rakheja S., Chang S.-C., Nikonov D.E., Young I.A., Naeemi A., Circuit simulation of magnetization dynamics and spin transport, Electron Dev, IEEE Trans, 61, 5, pp. 1553-1560, (2014); Chang S.-C., Iraei R.M., Manipatruni S., Nikonov D.E., Young I.A., Naeemi A., Design and analysis of copper and aluminum interconnects for all-spin logic, Electron Dev, IEEE Trans, 61, 8, pp. 2905-2911, (2014); Chang S.-C., Manipatruni S., Nikonov D.E., Young I.A., Naeemi A., Design and analysis of si interconnects for all-spin logic, Magn, IEEE Trans, 50, 9, pp. 1-13, (2014); Sun J.Z., Et al., A three-terminal spin-torque-driven magnetic switch, Appl Phys Lett, 95, 8, (2009); Behin-Aein B., Sarkar A., Datta S., Modeling circuits with spins and magnets for all-spin logic, Solid-state device research conference (ESSDERC), (2012)","S. Srinivasan; School of Electrical and Computer Engineering, Purdue University, West Lafayette, United States; email: srikant.srinivasan81@gmail.com","","Springer Netherlands","","","","","","","978-940076892-5; 978-940076891-8","","","English","Handb. of Spintron.","Book chapter","Final","","Scopus","2-s2.0-84956686308" +"Geana D.","Geana, Dan (6603859728)","6603859728","Phase Equilibria in Ternary Systems Carbon Dioxide + 1-Hexanol + n -Pentadecane and Carbon Dioxide + 1-Heptanol + n -Pentadecane: Modeling of Holes in Critical Surface and Miscibility Windows","2018","Journal of Chemical and Engineering Data","63","4","","994","1005","11","0","10.1021/acs.jced.7b00781","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85045421248&doi=10.1021%2facs.jced.7b00781&partnerID=40&md5=1f2a84bcae7929d6144b7a3fdcd96fb1","Department of Inorganic Chemistry, Physical Chemistry, and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, Bucharest, 011061, Romania","Geana D., Department of Inorganic Chemistry, Physical Chemistry, and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1-7 Gh. Polizu Street, Bucharest, 011061, Romania","In this paper, the modeling of holes in the critical surface and miscibility windows, in the ternary carbon dioxide + 1-hexanol + n-pentadecane and carbon dioxide + 1-heptanol + n-pentadecane systems, was made. A software for phase equilibrium (PHEQ) data management and applications was used for calculations with the cubic general equation of state (GEOS), developed by the author. The software PHEQ was extended for calculations of critical lines (module GEOS CRITHK), using the Heidemann and Khalil method, and liquid-liquid-vapor (llg) lines (module GEOS LLVE) in binary and ternary mixtures. These modules were used for the calculation of holes in critical surfaces, and of miscibility windows. Binary and quasi-binary measured phase equilibrium data by Scheidgen [Ph.D. Thesis, Ruhr-Universität Bochum, 1997] were necessary for understanding and modeling of ternary systems, regarding holes in critical surface and miscibility windows. For modeling, the equation of state Soave-Redlich-Kwong, integrated in the cubic GEOS form, coupled with the two-parameters conventional mixing rule was used. A simple semipredictive approach was adopted for the estimation of the two binary interaction parameters by a trial and error procedure for reproducing the temperature and pressure values of the two experimental double critical end points (DCEPs). A unique set of parameters obtained by this procedure was used to predict the critical and three phases llg lines for all quasi-binary systems at reduced mass fractions of n-pentadecane in the range between the two experimental DCEPs. The calculated holes in the critical surface and miscibility windows are in satisfactory agreement with the available experimental data. © 2017 American Chemical Society.","","Application programs; Binary mixtures; Carbon dioxide; Equations of state; Information management; Phase equilibria; Solubility; Ternary systems; Binary and ternary mixtures; Binary interaction parameter; Double critical end points; General equation of state; Phase equilibrium data; Quasi binary systems; Temperature and pressures; Trial-and-error procedures; Hydrocarbons","","","","","","","Geana D., Feroiu V., Equations of State. Phase Equilibria Applications, (2000); Michelsen M.L., Mollerup J.M., Thermodynamic Models: Fundamentals and Computational Aspects, (2004); Kontogeorgis G.M., Folas G.K., Thermodynamic Models for Industrial Applications. from Classical and Advanced Mixing Rules to Association Theories, (2010); Deiters U.K., Kraska T., High-Pressure Fluid Phase Equilibria. Phenomenology and Computation, (2012); Patton C.L., Kisler S.H., Luks K.D., Multiphase equilibrium behavior of a mixture of carbon dioxide, 1-decanol, and n-tetradecane, Supercritical Fluid Engineering. Fundamentals and Applications, 514, pp. 55-65, (1993); Peters C.J., Florusse L.J., Hahre S., De Swaan Arons J., Fluid multiphase equilibria and critical phenomena in binary and ternary mixtures of carbon dioxide, n-alkanols and tetradecane, Fluid Phase Equilib., 110, pp. 157-173, (1995); Scheidgen A.L., Fluidphasengleichgewichte binärer und ternärer Kohlendioxidmischungen mit schwertflüchtigen organischen Substanzen bis 100 MPa. Cosolvency effect, Miscibility windows, und Löcher in der kritischen Fläche, (1997); Gauter K., , measurements, modeling and computation, (1999); Gauter K., Heidemann R., Peters C.J., Modeling of multiphase equilibria in ternary systems of carbon dioxide as the near-critical solvent and two low-volatile solutes, Fluid Phase Equilib., 158-160, pp. 133-141, (1999); Scheidgen A.L., Schneider G.M., Fluid phase equilibria of (carbon dioxide + a 1-alkanol + an alkane) up to 100 MPa and T = 393 K: Cosolvency effect, miscibility windows, and holes in the critical surface, J. Chem. Thermodyn., 32, pp. 1183-1201, (2000); Gauter K., Peters C.J., Scheidgen A.L., Schneider G.M., Cosolvency effects, miscibility windows and two-phase lg holes in three-phase llg surfaces in ternary systems: A status report, Fluid Phase Equilib., 171, pp. 127-149, (2000); Secuianu C., Feroiu V., Geana D., High-pressure vapor-liquid and vapor-liquid-liquid equilibria in the carbon dioxide + 1-heptanol system, Fluid Phase Equilib., 270, pp. 109-115, (2008); Secuianu C., Feroiu V., Geana D., High-pressure phase equilibria in the (carbon dioxide + 1-hexanol) system, J. Chem. Thermodyn., 42, pp. 1286-1291, (2010); Secuianu C., Feroiu V., Geana D., Phase Behavior for the Carbon Dioxide + n-Pentadecane Binary System, J. Chem. Eng. Data, 55, pp. 4255-4259, (2010); Secuianu C., Feroiu V., Geana D., Investigation of phase equilibria in the ternary system carbon dioxide + 1-heptanol + pentadecane, Fluid Phase Equilib., 261, pp. 337-342, (2007); Heidemann R.A., Khalil A.M., The calculation of critical points, AIChE J., 26, pp. 769-779, (1980); Geana D., A new equation of state for fluids. I. Applications to PVT calculations for pure fluids, Rev. Chim. (Bucharest), 37, pp. 303-309, (1986); Geana D., A new equation of state for fluids. II. Applications to phase equilibria, Rev. Chim. (Bucharest), 37, pp. 951-959, (1986); Geana D., A new equation of state for fluids. III. Generalization of the cubic equations of state of the van der Waals type, Rev. Chim. (Bucharest), 38, pp. 975-979, (1987); Geana D., Feroiu V., Thermodynamic properties of pure fluids using the GEOS3C equation of state, Fluid Phase Equilib., 174, pp. 51-68, (2000); Geana D., Rus L., Phase Equilibria Database and Calculation Program for Pure Component Systems and Mixtures, Proc. of Romanian International Conference on Chemistry and Chemical Engineering, RICCCE XIV, 2, pp. 170-178, (2005); Van Konynenburg P.H., Scott R.L., Critical lines and phase equilibria in binary van der Waals mixtures, Philos. Trans. R. Soc., A, 298, pp. 495-540, (1980); Bolz A., Deiters U.K., Peters C.J., De Loos T.W., Nomenclature for phase diagrams with particular reference to vapour-liquid and liquid-liquid equilibria, Pure Appl. Chem., 70, pp. 2233-2257, (1998); Privat R., Jaubert J.N., Classification of global fluid-phase equilibrium behaviors in binary systems, Chem. Eng. Res. Des., 91, pp. 1807-1839, (2013); Qian J.-W., Privat R., Jaubert J.N., Predicting the Phase Equilibria, Critical Phenomena, and Mixing Enthalpies of Binary Aqueous Systems Containing Alkanes, Cycloalkanes, Aromatics, Alkenes, and Gases (N2, CO2, H2S, H2) with the PPR78 Equation of State, Ind. Eng. Chem. Res., 52, pp. 16457-16490, (2013); Soave G., Equilibrium constants from a modified Redlich-Kwong equation of state, Chem. Eng. Sci., 27, pp. 1197-1203, (1972); Sima S., Feroiu V., Geana D., New high pressure vapour-liquid equilibrium data and density predictions for carbon dioxide + ethylacetate system, Fluid Phase Equilib., 325, pp. 45-52, (2012); Poling B.E., Prausnitz J.M., O'Connell J.P., Properties of Gases and Liquids, (2001); Cismondi M., Michelsen M.L., Global phase equilibrium calculations: Critical lines, critical endpoints and liquid-liquid-vapour equilibrium in binary mixtures, J. Supercrit. Fluids, 39, pp. 287-295, (2007); GPEQ Software, (2007); Stockfleth R., Dohrn R., An algorithm for calculating critical points in multicomponent mixtures which can easily be implemented in existing programs to calculate phase equilibria, Fluid Phase Equilib., 145, pp. 43-52, (1998); Secuianu C., Feroiu V., Geana D., Phase equilibria of carbon dioxide + 1-nonanol system at high pressures, J. Supercrit. Fluids, 55, pp. 653-661, (2010); Ionita S., Feroiu V., Geana D., Phase Equilibria of the Carbon Dioxide + 1-Decanol System at High Pressures, J. Chem. Eng. Data, 58, pp. 3069-3077, (2013); Secuianu C., Ionita S., Feroiu V., Geana D., High pressures phase equilibria of carbon dioxide + 1-undecanol system and their potential role in carbon capture and storage, J. Chem. Thermodyn., 93, pp. 360-373, (2016); Bogatu C., Duta A., De Loos T.W., Geana D., Modelling fluid phase equilibria in the binary system trifluoromethane + 1-phenylpropane, Fluid Phase Equilib., 428, pp. 190-202, (2016); Secuianu C., Feroiu V., Geana D., Phase behavior of the carbon dioxide + 1-dodecanol system at high pressures, Fluid Phase Equilib., 428, pp. 62-75, (2016); Cismondi M., Brignole E.A., Mollerup J., Rescaling of three-parameter equations of state: PC-SAFT and SPHCT, Fluid Phase Equilib., 234, pp. 108-121, (2005); Polishuk I., Standardized Critical Point-Based Numerical Solution of Statistical Association Fluid Theory Parameters: The Perturbed Chain-Statistical Association Fluid Theory Equation of State Revisited, Ind. Eng. Chem. Res., 53, pp. 14127-14141, (2014); Geana D., A non-cubic hard-sphere perturbed equation of state for representing PVT and phase equilibria behavior of fluids, Proc. Rom. Acad., Ser. B, 1-2, pp. 3-10, (2003); Geana D., A non-cubic hard-sphere perturbed equation of state for representing phase equilibria behavior of fluid mixtures, Proc. Rom. Acad., Ser. B, 1, pp. 9-14, (2005); Polishuk I., Hybridizing SAFT and Cubic EOS: What can be achieved?, Ind. Eng. Chem. Res., 50, pp. 4183-4198, (2011)","D. Geana; Department of Inorganic Chemistry, Physical Chemistry, and Electrochemistry, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, Bucharest, 1-7 Gh. Polizu Street, 011061, Romania; email: d_geana@chim.upb.ro","","American Chemical Society","","","","","","00219568","","JCEAA","","English","J Chem Eng Data","Article","Final","","Scopus","2-s2.0-85045421248" +"Keller S.M.; Liang C.-Y.; Carman G.P.","Keller, Scott M. (35242642700); Liang, Cheng-Yen (55957891900); Carman, Gregory P. (7101801087)","35242642700; 55957891900; 7101801087","Voltage control of single magnetic domain nanoscale heterostructure, analysis and experiments","2016","Conference Proceedings of the Society for Experimental Mechanics Series","7","","","231","234","3","0","10.1007/978-3-319-21762-8_28","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84952322217&doi=10.1007%2f978-3-319-21762-8_28&partnerID=40&md5=bf55d34185836a6b4bf88081d20d2a93","Department of Mechanical and Aerospace Engineering, Translational Applications of Nanoscale Multiferroic Systems TANMS, University of California, Los Angeles, 90095, CA, United States","Keller S.M., Department of Mechanical and Aerospace Engineering, Translational Applications of Nanoscale Multiferroic Systems TANMS, University of California, Los Angeles, 90095, CA, United States; Liang C.-Y., Department of Mechanical and Aerospace Engineering, Translational Applications of Nanoscale Multiferroic Systems TANMS, University of California, Los Angeles, 90095, CA, United States; Carman G.P., Department of Mechanical and Aerospace Engineering, Translational Applications of Nanoscale Multiferroic Systems TANMS, University of California, Los Angeles, 90095, CA, United States","Micromagnetic simulations of magnetoelastic nanostructures traditionally rely on either the Stoner-Wohlfarth model or the Landau-Lifshitz-Gilbert LLG model assuming uniform strain (and/or assuming uniform magnetization). While the uniform strain assumption is reasonable when modeling magnetoelastic thin films, this constant strain approach becomes increasingly inaccurate for smaller in-plane nanoscale structures. This paper presents analytical work verified with experimental data to significantly improve simulation of finite structures by fully coupling LLG with elastodynamics, i.e. the partial differential equations are intrinsically coupled. © The Society for Experimental Mechanics, Inc. 2016.","","Magnetic domains; Mechanics; Nanotechnology; Constant strains; Finite structures; Landau-Lifshitz-Gilbert; Magneto-elastic; Micromagnetic simulations; Nanoscale structure; Single magnetic domains; Stoner-Wohlfarth model; Nanomagnetics","","","","","National Science Foundation, NSF, (EEC-1160504); National Science Foundation, NSF","This work was supported by the NSF Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS), under Cooperative Agreement Award EEC-1160504.","Ma J., Hu J.M., Li Z., Nan C.W., Recent Progress in multiferroic magnetoelectric composites: From bulk to thin films, Adv. Mater, 23, pp. 1062-1087, (2011); Zhu B., Lo C.C.H., Lee S.J., Jiles D.C., Micromagnetic modeling of the effects of stress on magnetic properties, J. Appl. Phys, 89, pp. 7009-7011, (2001); Hu R.L., Soh A.K., Zheng G.P., Ni Y., Micromagnetic modeling studies on the effects of stress on magnetization reversal and dynamic hysteresis, J. Magn. Magn. Mater, 301, pp. 458-468, (2006); Chen Y.J., Fitchorov T., Vittoria C., Harris V.G., Electrically controlled magnetization switching in a multiferroic heterostructure, Appl. Phys. Lett, (2010); Hu J.M., Sheng G., Zhang J.X., Nan C.W., Chen L.Q., Phase-field simulation of electric-field-induced in-plane magnetic domain switching in magnetic/ferroelectric layered heterostructures, J. Appl. Phys, (2011); Bur A., Wu T., Hockel J., Hsu C.J., Kim H.K.D., Chung T.K., Wong K., Wang K.L., Carman G.P., Strain-induced magnetization change in patterned ferromagnetic nickel nanostructures, J. Appl. Phys, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Switching dynamics of a magnetostrictive single-domain nanomagnet subjected to stress, Phys. Rev. B, (2011); Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using multiferroic single-domain nanomagnets, Appl. Phys. Lett, (2010); Banas L., Numerical methods for the Landau-Lifshitz-Gilbert equation, Numer. Anal. Its Appl, 3401, pp. 158-165, (2005); Shu Y.C., Lin M.P., Wu K.C., Micromagnetic modeling of magnetostrictive materials under intrinsic stress, Mech. Mater, 36, pp. 975-997, (2004); Zhang J.X., Chen L.Q., Phase-field microelasticity theory and micromagnetic simulations of domain structures in giant magnetostrictive materials, Acta Mater, 53, pp. 2845-2855, (2005); O'Handley R.C., Modern Magnetic Material: Principles and Applications, (2000)","S.M. Keller; Department of Mechanical and Aerospace Engineering, Translational Applications of Nanoscale Multiferroic Systems TANMS, University of California, Los Angeles, 90095, United States; email: smkeller@ucla.edu","Thakre P.R.; Ralph C.; Silberstein M.; Singh R.","Springer New York LLC","","SEM Annual Conference and Exposition on Experimental and Applied Mechanics, 2015","8 June 2015 through 11 June 2015","Costa Mesa","157329","21915644","978-331921761-1","","","English","Conf. Proc. Soc. Exp. Mech. Ser.","Conference paper","Final","","Scopus","2-s2.0-84952322217" +"Bajpai U.; Nikolić B.K.","Bajpai, Utkarsh (57204777363); Nikolić, Branislav K. (7006055333)","57204777363; 7006055333","Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions","2019","Physical Review B","99","13","134409","","","","47","10.1103/PhysRevB.99.134409","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85064126872&doi=10.1103%2fPhysRevB.99.134409&partnerID=40&md5=e5d15b0ac518d259d597f261678eb646","Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","Bajpai U., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Nikolić B.K., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States","The conventional Landau-Lifshitz-Gilbert (LLG) equation is a widely used tool to describe the dynamics of local magnetic moments, viewed as classical vectors of fixed length, with their change assumed to take place simultaneously with the cause. Here we demonstrate that recently developed [M. D. Petrović, Phys. Rev. Appl. 10, 054038 (2018)10.1103/PhysRevApplied.10.054038] self-consistent coupling of the LLG equation to a time-dependent quantum-mechanical description of electrons - where nonequilibrium spin density from time-dependent nonequilibrium Green function (TDNEGF) calculations is inserted within a torque term into the LLG equation while local magnetic moments evolved by the LLG equation introduce time-dependent potential in the quantum Hamiltonian of electrons - microscopically generates time-retarded damping in the LLG equation described by a memory kernel that is also spatially dependent. For sufficiently slow dynamics of local magnetic moments on the memory time scale, the kernel can be expanded into power series to extract the Gilbert damping (proportional to the first time derivative of magnetization) and magnetic inertia (proportional to the second time derivative of magnetization) terms whose parameters, however, are time-dependent in contrast to time-independent parameters used in the conventional LLG equation. We use examples of single or multiple local magnetic moments precessing in an external magnetic field, as well as field-driven motion of a magnetic domain wall (DW), to quantify the difference in their time evolution computed from the conventional LLG equation versus the TDNEGF+LLG quantum-classical hybrid approach. The faster DW motion predicted by the TDNEGF+LLG approach reveals that important quantum effects, stemming essentially from a finite amount of time that it takes for a conduction electron spin to react to the motion of classical local magnetic moments, are missing from conventional classical micromagnetics simulations. We also demonstrate a large discrepancy between the TDNEGF+LLG-computed numerically exact and, therefore, nonperturbative result for charge current pumped by a moving DW and the same quantity computed by a perturbative spin motive force formula combined with the conventional LLG equation. © 2019 American Physical Society.","","Damping; Domain walls; Electrospinning; Hamiltonians; Magnetic domains; Magnetization; Quantum optics; Conduction electrons; External magnetic field; Landau-Lifshitz-Gilbert equations; Local magnetic moments; Micromagnetics simulations; Non-equilibrium green functions; Quantum Hamiltonians; Time-dependent potentials; Magnetic moments","","","","","XSEDE; National Science Foundation, NSF; Norsk Sykepleierforbund, NSF, (ACI-1548562, CHE1566074)","Funding text 1: We thank Z. Yuan for insightful discussions. This work was supported by NSF Grant No. CHE 1566074. The supercomputing time is provided by XSEDE, which is supported by NSF Grant No. ACI-1548562.; Funding text 2: We thank Z. Yuan for insightful discussions. This work was supported by NSF Grant No. CHE 1566074. The supercomputing time is provided by XSEDE, which is supported by NSF Grant No. ACI-1548562. ","Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Wieser R., Phys. Rev. Lett., 110, (2013); Wieser R., Eur. Phys. J. B, 88, (2015); Kumar D., Adeyeye A.O., J. Phys. D, 50, (2017); Evans R.F.L., Fan W.J., Chureemart P., Ostler T.A., Ellis M.O.A., Chantrell R.W., J. Phys.: Condens. Matter, 26, (2014); Nunez A.S., Duine R.A., Phys. Rev. B, 77, (2008); Kambersky V., Phys. Rev. B, 76, (2007); Gilmore K., Idzerda Y.U., Stiles M.D., Phys. Rev. Lett., 99, (2007); Mahfouzi F., Kim J., Kioussis N., Phys. Rev. B, 96, (2017); Ralph D., Stiles M., J. Magn. Magn. Mater., 320, (2008); Tserkovnyak Y., Brataas A., Bauer G.E.W., Halperin B.I., Rev. 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B, 77, (2008); Yang S.A., Beach G.S.D., Knutson C., Xiao D., Niu Q., Tsoi M., Erskine J.L., Phys. Rev. Lett., 102, (2009); Freimuth F., Blugel S., Mokrousov Y.; Sayad M., Rausch R., Potthoff M., Phys. Rev. Lett., 117, (2016); Mondal P., Bajpai U., Petrovic M.D., Plechac P., Nikolic B.K., Phys. Rev. B, 99, (2019); Mahfouzi F., Nikolic B.K., Phys. Rev. B, 90, (2014); Elze H.-T., Phys. Rev. A, 85, (2012); Weston J., Waintal X., Phys. Rev. B, 93, (2016)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85064126872" +"Yao Z.; Cui H.; Wang Y.E.","Yao, Zhi (56380891100); Cui, Han (55774086800); Wang, Yuanxun Ethan (57202387207)","56380891100; 55774086800; 57202387207","3D Finite-Difference Time-Domain (FDTD) Modeling of Nonlinear RF Thin Film Magnetic Devices","2019","IEEE MTT-S International Microwave Symposium Digest","","","8700968","110","113","3","2","10.1109/mwsym.2019.8700968","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85069951735&doi=10.1109%2fmwsym.2019.8700968&partnerID=40&md5=eec3d991ec69fbe4b03bd9f897cbf447","University of California, Los Angeles, United States","Yao Z., University of California, Los Angeles, United States; Cui H., University of California, Los Angeles, United States; Wang Y.E., University of California, Los Angeles, United States","An unconditionally stable three-dimensional (3D) finite-difference time-domain (FDTD) algorithm has been proposed to predict the dynamic interaction between nonlinear magnetic spins and electromagnetic (EM) fields in nonlinear magnetic devices. The proposed modeling solves simultaneously Maxwell's equations and the Landau-Lifshitz-Gilbert (LLG) equation with full nonlinear effects. The accuracy of the modeling has been validated by 1. Small signal simulation of a linear ferrite isolator and 2. Large signal simulation of the dispersive permeability of a continuous ferrite film. The simulations agree with the theoretical and experimental predictions. The fact that the 2-thick film exhibits strong nonlinearity shows the potential of magnetic thin film applied in miniature RF front ends. © 2019 IEEE.","electromagnetics; ferrite; ferromagnetic; finite difference time domain methods; magnetics; multiphysics; nonlinear problems; thin films","Ferrite; Finite difference time domain method; Magnetic devices; Maxwell equations; Nonlinear equations; 3d finite difference time domains; Electromagnetics; Ferromagnetics; Finite-difference time-domain modeling; Magnetic; Multi-physics; Nonlinear magnetics; Nonlinear problems; Thin-films; Unconditionally stable; Thin films","","","","","Defense Advanced Research Projects Agency, DARPA, (W911NF-17-1-0100); Defense Advanced Research Projects Agency, DARPA","This work was supported by the Defense Advanced Research Projects Agency (DARPA) Magnetic Miniaturized and Monolithically Integrated Components (M3IC) Program under award W911NF-17-1-0100.","Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proceedings of the IRE, 44, 10, pp. 1270-1284, (1956); Zhen F., Chen Z., Zhang J., Toward the development of a threedimensional unconditionally stable finite-difference time-domain method, IEEE Trans. Microw. Theory Tech., 48, 9, pp. 1550-1558, (2000); Namiki T., A new FDTD algorithm based on alternating-direction implicit method, IEEE Trans. Microw. Theory Tech., 47, 10, pp. 2003-2007, (1999); Wigen P.E., Nonlinear phenomena and chaos in magnetic materials, Nonlinear Phenomena and Chaos in Magnetic Materials: World Scientific, pp. 1-12, (1994); Esquinazi P., Magnetic Carbon, Handbook of Magnetism and Advanced Magnetic Materials, 2, pp. 730-731, (2007); Yao Z., Cui H., Itoh T., Wang Y.E., Multiphysics time-domain modeling of nonlinear permeability in thin-film magnetic material, IEEE/MTT-S International Microwave Symposium-IMS, pp. 208-211, (2018); Yao Z., Tok R.U., Itoh T., Wang Y.E., A multiscale unconditionally stable time-domain (MUST) solver unifying electrodynamics and micromagnetics, IEEE Trans. Microw. Theory Tech., 66, 6, pp. 2683-2696, (2018); Yao Z., Wang Y.E., 3D unconditionally stable FDTD modeling of micromagnetics and electrodynamics, IEEE/MTT-S International Microwave Symposium-IMS, pp. 12-15, (2017); Wu M., Hoffmann A., Et al., Solid State Physics, 64, (2013); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, Journal of Computational and Applied Mathematics, 176, 2, pp. 263-281, (2005); Aziz M.M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, Progress in Electromagnetics Research B, 15, (2009); Taflove A., Hagness S.C., Computational Electrodynamics: The Finite-difference Time-domain Method, (2000); Lax B., Button K.J., Microwave Ferrites and Ferrimagnetics, (1962); Bernardi P., Valdoni F., Fundamentals of a new class of magnetically tunable waveguide filters, IEEE Transactions on Magnetics, 2, 3, pp. 264-268, (1966); Uher J., Arndt F., Bornemann J., Field theory design of ferriteloaded waveguide nonreciprocal phase shifters with multisection ferrite or dielectric slab impedance transformers, IEEE Trans. Microw. Theory Tech., 35, 6, pp. 552-560, (1987); Engquist B., Majda A., Absorbing boundary conditions for numerical simulation of waves, Proceedings of the National Academy of Sciences, 74, 5, pp. 1765-1766, (1977)","","","Institute of Electrical and Electronics Engineers Inc.","","2019 IEEE MTT-S International Microwave Symposium, IMS 2019","2 June 2019 through 7 June 2019","Boston","149920","0149645X","978-172811309-8","IMIDD","","English","IEEE MTT S Int Microwave Symp Dig","Conference paper","Final","","Scopus","2-s2.0-85069951735" +"Jiang S.; Sun L.; Yin Y.; Fu Y.; Luo C.; Zhai Y.; Zhai H.","Jiang, Sheng (56872163800); Sun, Li (57199012494); Yin, Yuli (55637843400); Fu, Yu (55712875200); Luo, Chen (57203166737); Zhai, Ya (7102983196); Zhai, Hongru (7202968348)","56872163800; 57199012494; 55637843400; 55712875200; 57203166737; 7102983196; 7202968348","Ferromagnetic resonance linewidth and two-magnon scattering in Fe1-xGdx thin films","2017","AIP Advances","7","5","056029","","","","24","10.1063/1.4978004","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85014517203&doi=10.1063%2f1.4978004&partnerID=40&md5=e1c51b031572b66eedd0f486954ea13d","Department of Physics, Southeast University, Nanjing, 211189, China; College of Physics and Electronic Engineering, Hainan Normal University, Haikou, 571158, China; National Laboratory of Solid Microstructures, Center of Modern Analysis, Nanjing University, Nanjing, 210093, China","Jiang S., Department of Physics, Southeast University, Nanjing, 211189, China; Sun L., Department of Physics, Southeast University, Nanjing, 211189, China, College of Physics and Electronic Engineering, Hainan Normal University, Haikou, 571158, China; Yin Y., Department of Physics, Southeast University, Nanjing, 211189, China; Fu Y., Department of Physics, Southeast University, Nanjing, 211189, China; Luo C., Department of Physics, Southeast University, Nanjing, 211189, China; Zhai Y., Department of Physics, Southeast University, Nanjing, 211189, China; Zhai H., National Laboratory of Solid Microstructures, Center of Modern Analysis, Nanjing University, Nanjing, 210093, China","Magnetization dynamics of Fe1-xGdx thin films (0 ≤ x ≤ 22%) has been investigated by ferromagnetic resonance (FMR). Out-of-plane magnetic field orientation dependence of resonance field and linewidth has been measured. Resonance field and FMR linewidth have been fitted by the free energy of our system and Landau-Lifshitz-Gilbert (LLG) equation. It is found that FMR linewidth contains huge extrinsic components including two-magnon scattering contribution and inhomogeneous broadening for FeGd alloy thin films. In addition, the intrinsic linewidth and real damping constants have been obtained by extracting the extrinsic linewidth. The damping constant enhanced from 0.011 to 0.038 as Gd dopants increase from 0 to 22% which originates from the enhancement of L-S coupling in FeGd thin films. Besides, gyromagnetic ratio, Landé factor g and magnetic anisotropy of our films have also been determined. © 2017 Author(s).","","Damping; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Free energy; Linewidth; Magnetic anisotropy; Resonance; Extrinsic components; Ferromagnetic resonance (FMR); Ferromagnetic resonance linewidth; Inhomogeneous broadening; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Out-of-plane magnetic fields; Two-magnon scattering; Thin films","","","","","National Natural Science Foundation of China, NSFC, (11364015, 11504047, 51571062, 61306121, 61427812); Natural Science Foundation of Jiangsu Province, (BK20141328)","This work is supported by NSFC (Nos. 61427812, 51571062, 11504047, 61306121 and 11364015), NSF of Jiangsu Province of China (No. BK20141328).","Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Chung A., Deen J., Lee J.S., Meyyappan M., Nanotechnology, 21, (2010); Mohseni S.M., Sani S.R., Persson J., Nguyen T.N.A., Chung S., Pogoryelov Y., Muduli P.K., Iacocca E., Eklund A., Dumas R.K., Bonetti S., Deac A., Hoefer M.A., Akerman J., Science, 339, (2013); Back C., Allenspach R., Weber W., Parkin S., Weller D., Garwin E., Siegmann H., Science, 285, (1999); Woltersdorf G., Kiessling M., Meyer G., Thiele J.-U., Back C.H., Phys. 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Lett., 97, (2006); Zhang W., Jiang S., Wong P.K.J., Sun L., Wang Y.K., Wang K., De Jong M.P., Van der Wiel W.G., Van der Laan G., Zhai Y., J. Appl. Phys., 115, (2014)","Y. Zhai; Department of Physics, Southeast University, Nanjing, 211189, China; email: yazhai@seu.edu.cn","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85014517203" +"Couture S.; Chang R.; Volvach I.; Goncharov A.; Lomakin V.","Couture, S. (36536819800); Chang, R. (37261104600); Volvach, I. (55193500500); Goncharov, A. (56394838800); Lomakin, V. (35570326300)","36536819800; 37261104600; 55193500500; 56394838800; 35570326300","Coupled Finite-Element Micromagnetic - Integral Equation Electromagnetic Simulator for Modeling Magnetization - Eddy Currents Dynamics","2017","IEEE Transactions on Magnetics","53","12","8016648","","","","6","10.1109/TMAG.2017.2745470","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85028530173&doi=10.1109%2fTMAG.2017.2745470&partnerID=40&md5=44df5164bd174248091e9387deaf1824","Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, CA, United States; Western Digital Corporation, San Jose, 95119, CA, United States","Couture S., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, CA, United States; Chang R., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, CA, United States; Volvach I., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, CA, United States; Goncharov A., Western Digital Corporation, San Jose, 95119, CA, United States; Lomakin V., Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, CA, United States","A formulation for coupled Landau-Lifshitz-Gilbert (LLG) and magnetoquasistatic Maxwell equations (MEs) is reported. The formulation has no approximations apart from neglecting the displacement current, i.e., the magnetoquasistatic approximation, and is applicable for describing a broad range of magnetization and electromagnetic phenomena. The formulation is based on two parallel solvers: one for the non-linear LLG equation and the other for the MEs. These solvers are coupled at the computation of the magnetic field, which occurs during the process of solving the two equations. Solving the LLG equation is done through an implicit time integration scheme, and solving the MEs is done through a time-domain integral equations' formulation. The framework was implemented as a part of the high-performance micromagnetic simulator FastMag, and it allows modeling magnetization and electromagnetic dynamics effects in highly complex magnetic materials and devices. Numerical results obtained for a test problem are compared with a known analytical solution to validate the solver and illustrate the interactions between eddy currents and magnetization dynamics. Moreover, simulation results for a non-linear problem, namely, the switching of a ferromagnetic disk, are presented, which illustrate the role that eddy currents can play in magnetization dynamics. © 1965-2012 IEEE.","Eddy currents; integral equations; micromagnetics; nonlinear magnetics","Dynamics; Integral equations; Magnetic anisotropy; Magnetic domains; Magnetic materials; Magnetism; Magnetization; Magnetostatics; Maxwell equations; Electromagnetic dynamics; Electromagnetic phenomena; Electromagnetic simulators; Implicit time integration; Landau-Lifshitz-Gilbert; Micromagnetic simulators; Perpendicular magnetic anisotropy; Time domain integral equations; Eddy currents","","","","","","","Basso V., Et al., Power losses in magnetic laminations with hysteresis: Finite element modeling and experimental validation, J. Appl. Phys., 81, 8, pp. 5606-5608, (1997); Chevalier T., Kedous-Lebouc A., Cornut B., Cester C., Estimation of magnetic loss in an induction motor fed with sinusoidal supply using a finite element software and a new approach to dynamic hysteresis, IEEE Trans. Magn., 35, 5, pp. 3400-3402, (1999); Dlala E., Belahcen A., Pippuri J., Arkkio A., Interdependence of hysteresis and eddy-current losses in laminated magnetic cores of electrical machines, IEEE Trans. Magn., 46, 2, pp. 306-309, (2010); Rodriguez A.A., Valli A., Eddy Current Approximation of Maxwell Equations, (2010); Torres L., Martinez E., Lopez-Diaz L., Alejos O., About the inclusion of eddy currents in micromagnetic computations, Phys. B, Condens. Matter, 343, 1, pp. 257-261, (2004); Hrkac G., Et al., Three-dimensional micromagnetic finite element simulations including eddy currents, J. Appl. Phys., 97, 10, (2005); Takano K., Et al., Micromagnetics and eddy current effects in magnetic recording heads, IEEE Trans. Magn., 43, 6, pp. 2184-2186, (2007); Chang R., Lomakin V., Michielssen E., Coupling electromagnetics with micromagnetics, Proc. IEEE Antennas Propag. Soc. Int. Symp, pp. 1-2, (2012); Brown W.F., Micromagnetics, (1963); Haus H.A., Melcher J.R., Electromagnetic Fields and Energy, (1989); Knoepfel H.E., Magnetic Fields, (2000); Brown P.N., Byrne G.D., Hindmarsh A.C., VODE: A variablecoefficient ODE solver, SIAM J. Sci. Stat. Comput., 10, 5, pp. 1038-1051, (1989); Jin J.-M., The Finite Element Method Electromagnetics, (2014); Bossavit A., Verite J.-C., A mixed FEM-BIEM method to solve 3-D eddy-current problems, IEEE Trans. Magn., MAG-18, 2, pp. 431-435, (1982); Jackson J.D., Classical Electrodynamics, (1999); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetizing fields, IEEE Trans. Magn., 26, 2, pp. 415-417, (1990); Saad Y., Iterative Methods for Sparse Linear Systems, (2003); Bleszynski E., Bleszynski M., Jaroszewicz T., AIM: Adaptive integral method for solving large-scale electromagnetic scattering and radiation problems, Radio Sci., 31, 5, pp. 1225-1251, (1996); Chang R., Li S., Lubarda M.V., Livshitz B., Lomakin V., FastMag: Fast micromagnetic simulator for complex magnetic structures, J. Appl. Phys., 109, 7, (2011); Li S., Chang R., Boag A., Lomakin V., Fast electromagnetic integral-equation solvers on graphics processing units, IEEE Antennas Propag. Mag., 54, 5, pp. 71-87, (2012); Cullity B.D., Graham C.D., Introduction to Magnetic Materials, (2009); Soohoo R.F., Microwave Magnetics, (1985)","S. Couture; Center for Memory and Recording Research, Department of Electrical and Computer Engineering, University of California, San Diego, San Diego, 92093, United States; email: scouture@ucsd.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85028530173" +"Je S.-G.; Rojas-Sánchez J.-C.; Pham T.H.; Vallobra P.; Malinowski G.; Lacour D.; Fache T.; Cyrille M.-C.; Kim D.-Y.; Choe S.-B.; Belmeguenai M.; Hehn M.; Mangin S.; Gaudin G.; Boulle O.","Je, Soong-Geun (37112432800); Rojas-Sánchez, Juan-Carlos (19337710600); Pham, Thai Ha (57200498433); Vallobra, Pierre (57190178681); Malinowski, Gregory (6602479109); Lacour, Daniel (57000017100); Fache, Thibaud (57195614314); Cyrille, Marie-Claire (6601998453); Kim, Dae-Yun (56123358300); Choe, Sug-Bong (7101751713); Belmeguenai, Mohamed (25822438800); Hehn, Michel (7004393170); Mangin, Stéphane (56250204200); Gaudin, Gilles (23978206500); Boulle, Olivier (12546128100)","37112432800; 19337710600; 57200498433; 57190178681; 6602479109; 57000017100; 57195614314; 6601998453; 56123358300; 7101751713; 25822438800; 7004393170; 56250204200; 23978206500; 12546128100","Spin-orbit torque-induced switching in ferrimagnetic alloys: Experiments and modeling","2018","Applied Physics Letters","112","6","062401","","","","72","10.1063/1.5017738","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85041430387&doi=10.1063%2f1.5017738&partnerID=40&md5=56cc1294876e650bf1a3b51e5e597bd3","SPINTEC, University Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec, Grenoble, 38000, France; Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; CEA, LETI, MINATEC Campus, Grenoble, F-38054, France; Department of Physics, Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea; LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse, 93430, France; Center for X-ray Optics, Lawrence Berkeley National Laboratoryc, Berkeley, 94720, CA, United States; Department of Materials Science and Engineering, Korea University, Seoul, 02481, South Korea","Je S.-G., SPINTEC, University Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec, Grenoble, 38000, France, Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France, Center for X-ray Optics, Lawrence Berkeley National Laboratoryc, Berkeley, 94720, CA, United States, Department of Materials Science and Engineering, Korea University, Seoul, 02481, South Korea; Rojas-Sánchez J.-C., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Pham T.H., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Vallobra P., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Malinowski G., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Lacour D., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Fache T., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Cyrille M.-C., CEA, LETI, MINATEC Campus, Grenoble, F-38054, France; Kim D.-Y., Department of Physics, Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea; Choe S.-B., Department of Physics, Institute of Applied Physics, Seoul National University, Seoul, 08826, South Korea; Belmeguenai M., LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse, 93430, France; Hehn M., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Mangin S., Institut Jean Lamour, UMR 7198, CNRS-Université de Lorraine, Vandoeuvre lès Nancy, 54506, France; Gaudin G., SPINTEC, University Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec, Grenoble, 38000, France; Boulle O., SPINTEC, University Grenoble Alpes, CEA, CNRS, Grenoble INP, INAC-Spintec, Grenoble, 38000, France","We investigate spin-orbit torque (SOT)-induced switching in rare-earth-transition metal ferrimagnetic alloys using W/CoTb bilayers. The switching current is found to vary continuously with the alloy concentration, and no reduction in the switching current is observed at the magnetic compensation point despite a very large SOT efficiency. A model based on coupled Landau-Lifschitz-Gilbert (LLG) equations shows that the switching current density scales with the effective perpendicular anisotropy which does not exhibit strong reduction at the magnetic compensation, explaining the behavior of the switching current density. This model also suggests that conventional SOT effective field measurements do not allow one to conclude whether the spins are transferred to one sublattice or just simply to the net magnetization. The effective spin Hall angle measurement shows an enhancement of the spin Hall angle with the Tb concentration which suggests an additional SOT contribution from the rare earth Tb atoms. © 2018 Author(s).","","Ferrimagnetism; Orbits; Rare earths; Switching; Transition metal alloys; Transition metals; Tungsten; Alloy concentration; Effective field; Magnetic compensation; Model-based OPC; Perpendicular anisotropy; Rare earth transition metal; Switching current density; Switching currents; Rare earth alloys","","","","","National Research Foundation, NRF; Ministry of Science, ICT and Future Planning, MSIP, (17-BT-02, 2015M3D1A1070465, 2015R1A2A1A05001698); National Research Foundation of Korea, NRF; Ministry of Education, Science and Technology, MEST, (2012K1A4A3053565); Daegu Gyeongbuk Institute of Science and Technology, DGIST","This work was supported by the project ICEEL INTERCARNOT OPTICSWITCH. S.G.J. was partially supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (MEST) (2012K1A4A3053565) and by the DGIST R&D program of the Ministry of Science, ICT and future Planning (17-BT-02). D.Y.K. and S.B.C. were supported by grants from NRF funded by the Ministry of Science, ICT and Future Planning of Korea (MSIP) (2015R1A2A1A05001698 and 2015M3D1A1070465). S.G.J also acknowledges the support from the Future Materials Discovery Program through the NRF funded by the MSIP (2015M3D1A1070465).","Miron I.M., Garello K., Gaudin G., Zermatten P.-J., Costache M.V., Auffret S., Bandiera S., Rodmacq B., Schuhl A., Gambardella P., Nature, 476, pp. 189-193, (2011); Liu L., Lee O.J., Gudmundsen T.J., Ralph D.C., Buhrman R.A., Phys. Rev. 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B, 90, (2014); Malozemoff A., Slonczewski J., Magnetic Domain Walls in Bubble Materials, (1979); Hubert A., Theorie der Domänenwände in Geordneten Medien, (1974); Thiaville A., Rohart S., Jue E., Cros V., Fert A., Europhys. Lett., 100, (2012); Boulle O., Rohart S., Buda-Prejbeanu L.D., Jue E., Miron I.M., Pizzini S., Vogel J., Gaudin G., Thiaville A., Phys. Rev. Lett., 111, (2013); Tarasenko S.V., Stankiewicz A., Tarasenko V.V., Ferre J., J. Magn. Magn. Mater., 189, (1998); Schulz T., Lee K., Kruger B., Conte R.L., Karnad G.V., Garcia K., Vila L., Ocker B., Ravelosona D., Klaui M., Phys. Rev. B, 95, (2017); Reynolds N., Jadaun P., Heron J.T., Jermain C.L., Gibbons J., Collette R., Buhrman R.A., Schlom D.G., Ralph D.C., Phys. Rev. B, 95, 6, (2017); Ueda K., Pai C.-F., Tan A.J., Mann M., Beach G.S.D., Appl. Phys. Lett., 108, (2016); Hebler B., Hassdenteufe A., Reinhard P., Karl H., Albrecht M., Front. Mater., 3, (2016); Hadri M.S.E., Hehn M., Pirro P., Lambert C.-H., Malinowski G., Fullerton E.E., Mangin S., Phys. Rev. B, 94, (2016); Pai C.-F., Ou Y., Henrique Vilela-Leao L., Ralph D.C., Buhrman R.A., Phys. Rev. B, 92, (2015); Je S.-G., Kim D.-H., Yoo S.-C., Min B.-C., Lee K.-J., Choe S.-B., Phys. Rev. B, 88, (2013); Kim D.-Y., Park M.-H., Park Y.-K., Kim J.-S., Nam Y.-S., Kim D.-H., Je S.-G., Min B.-C., Choe S.-B., NPG ASIA Mater., 10, (2018); Belmeguenai M., Adam J.-P., Roussigne Y., Eimer S., Devolder T., Kim J.-V., Cherif S.M., Stashkevich A., Thiaville A., Phys. Rev. B, 91, (2015)","","","American Institute of Physics Inc.","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85041430387" +"Ahmad N.; Saeed A.; Khan S.; Hassan F.; Li W.J.; Shah S.A.; Majid A.; Han X.F.","Ahmad, Naeem (58834327800); Saeed, Ahmad (26028277700); Khan, Suleman (57007470400); Hassan, Fahad (57194941496); Li, W.J. (56524790600); Shah, Saqlain A. (35194611100); Majid, Abdul (57193352948); Han, X.F. (56411340200)","58834327800; 26028277700; 57007470400; 57194941496; 56524790600; 35194611100; 57193352948; 56411340200","Investigation of easy axis transition and magnetodynamics in Ni76Fe24 nanowires and Ni77Fe23 nanotubes synthesized by DC electrodeposition","2017","Journal of Alloys and Compounds","725","","","123","128","5","12","10.1016/j.jallcom.2017.05.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85024387940&doi=10.1016%2fj.jallcom.2017.05.012&partnerID=40&md5=45954b959fe092551cb021d6d5a2cb8c","Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, UCAS, Beijing, 100190, China; Department of Physics, Forman Christian College (University), Lahore, Pakistan; Department of Physics, University of Gujrat, Gujrat, Pakistan","Ahmad N., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, UCAS, Beijing, 100190, China; Saeed A., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan; Khan S., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan; Hassan F., Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan; Li W.J., Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, UCAS, Beijing, 100190, China; Shah S.A., Department of Physics, Forman Christian College (University), Lahore, Pakistan; Majid A., Department of Physics, University of Gujrat, Gujrat, Pakistan; Han X.F., Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, UCAS, Beijing, 100190, China","Well rounded, smooth and elegantly elongated Ni76Fe24 nanowires and Ni77Fe23 nanotubes were successfully fabricated inside the home made anodized aluminum oxide (AAO) templates at room temperature by cost effective DC electrodeposition. In order to explore surface information and atomic percentage, samples were characterized by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) respectively. It is observed that highly homogeneous and uniform nanowires with Length = 10 μm and diameter = 50 nm and nanotubes with Length = 8 μm and diameter = 50 nm are formed. Different magnetic parameters i.e. M-H curves, coercivity (Hc), saturation magnetization (Ms) and magnetization reversal mode were also investigated by vibrating sample magnetometer (VSM). It is observed from angular dependence of coercivity that magnetization reversal mechanism occurs by nucleation mode in Ni76Fe24 nanowires and combination of curling and nucleation in Ni77Fe23 nanotubes. Different magnetic interactions were ruled out with the help of delta M curves. It is found that dipole-dipole interactions dominate over shape anisotropy due to which the easy axis entirely re-oriented towards the perpendicular from the wire and tube axis. Furthermore this fact of easy axis transition was also confirmed by Ferromagnetic resonance (FMR) performed at frequency f = 9.8 GHz by sweeping magnetic field from parallel to perpendicular of nanocylinder axis. The ferromagnetic relaxation mechanism is explained on the basis spin–orbit interaction and s–d interaction mechanism using LLG equation. The MH loops of Ni77Fe23 nanotubes at low temperature confirms that thermal energy decreases at low temperature causing an increase in saturation magnetization. This study will be useful for the application of nanocylinders in various Spintronics devices. © 2017 Elsevier B.V.","Delta M curves; Effective anisotropy; Ferromagnetic nanowires and nanotubes; Ferromagnetic resonance; Magnetodynamics","Anisotropy; Binary alloys; Coercive force; Cylinders (shapes); Electrodeposition; Electrodes; Electron spin resonance spectroscopy; Energy dispersive spectroscopy; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetism; Magnetization; Magnetization reversal; Nanotubes; Nanowires; Nickel alloys; Nucleation; Saturation magnetization; Scanning electron microscopy; Temperature; Yarn; Delta M; Effective anisotropy; Energy dispersive spectroscopies (EDS); Ferromagnetic nanowire; Ferromagnetic resonance (FMR); Magnetization reversal mechanisms; Magnetodynamics; Vibrating sample magnetometer; Iron alloys","","","","","National Natural Science Foundation of China, NSFC, (1137435, 11434014, 51620105004); National Natural Science Foundation of China, NSFC; Chinese Academy of Sciences, CAS, (772409714, XDB07030200); Chinese Academy of Sciences, CAS; Higher Education Commission, Pakistan, HEC, (PM-IPFP/HRD/HEC/2011/354); Higher Education Commission, Pakistan, HEC","Naeem Ahmad is thankful to Higher Education Commission, Pakistan (HEC) of Pakistan for financial support [Grant No. PM-IPFP/HRD/HEC/2011/354]. This work was partially supported by the National Natural Science Foundation of China [NSFC, Grant No. 1137435, 11434014 and 51620105004]; the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (CAS) [Grant No. XDB07030200]. The plagiarism test has also been carried by HEC provided Turnitin with ID: 772409714 and similarity index lies within permissible range.","Grobis M.K., Hellwig O., Hauet T., Dobisz E., Albrecht, high-density bit patterned media: magnetic design and recording performance, IEEE Trans. Magn., 47, pp. 6-10, (2011); Prince B., Vertical 3D Memory Technologies, (2014); Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, pp. 190-194, (2008); Fratila R.M., Rivera-Ferna S., de la Fuente J.M., Shape matters: synthesis and biomedical applications of high aspect ratio magnetic nanomaterials, Nanoscale, 7, pp. 8233-8260, (2015); Vidal E.V., Ivanov Y.P., Mohammed H., Kosel J., A detailed study of the magnetization reversal in individual Ni nanowires, Appl. Phys. Lett., 106, 32403, (2015); Vivas G., Ivanov Y.P., Trabada D.G., Proenca M.P., Chubykalo-Fesenko O., Vazquez M., Magnetic properties of Co nanopillar arrays prepared from alumina templates, Nanotechnology, 24, (2013); Bran C., Ivanov Y.P., Garcia J., del Real R.P., Prida V.M., Chubykalo-Fesenko O., Vazquez M., Tuning the magnetization reversal process of FeCoCu nanowire arrays by thermal annealing, Appl. Phys., 114, (2013); Ivanov Y.P., Vivas L.G., Asenjo A., Chuvilin A., Chubykalo-Fesenko O.M., Magnetic structure of a single crystal hcp electrodeposited cobalt nanowire, Euro Phys. Lett., 102, (2013); Irfan M., Khan U., Li W., Adeela N., Javed, Han X.F., Mater. Lett., 180, pp. 235-238, (2016); Zeng H., Et al., Phys. Rev. B, 65, (2002); Niitzenadel C., Ziittel A., Chartouni D., Schmid G., Schlapbach L., Eur. Phys. J. DS, 245, (2000); Paluskar P.V., Lavrijsen R., Sicot M., Kohlhepp J.T., Swagten H.J.M., Koopmans B., Correlation between magnetism and spin-dependent transport in CoFeB alloys, Phys. Rev. Lett., 102, (2009); Ebels U., Duvail J.-L., Wigen P.E., Piraux L., Buda L.D., Ounadjela K., Phys. Rev. B, 64, (2001); Platow W., Anisimov A.N., Dunifer G.L., Farle M., Baberschke K., Correlations between ferromagnetic resonance linewidths and sample quality in the study of metallic ultrathin films, Phys. Rev. B, 58, (1998); Ahmad N., Yu T., Khan S., Majid A., Iqbal J., Shah S.A., Awan S.U., Han X.F., J. Supercond. Nov. Magn., (2016)","N. Ahmad; Spintronics Laboratory, Department of Physics, International Islamic University, Islamabad, Pakistan; email: naeem.ahmad@iiu.edu.pk","","Elsevier Ltd","","","","","","09258388","","JALCE","","English","J Alloys Compd","Article","Final","","Scopus","2-s2.0-85024387940" +"Rossi J.O.; Yamasaki F.S.; Schamiloglu E.; Barroso J.J.; Hasar U.C.","Rossi, Jose O. (7202397572); Yamasaki, Fernanda S. (49561878200); Schamiloglu, Edl (7006390232); Barroso, Joaquim J. (7103318266); Hasar, Ugur C. (55885911000)","7202397572; 49561878200; 7006390232; 7103318266; 55885911000","Operation analysis of a novel concept of RF source known as gyromagnetic line","2017","SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, IMOC 2017","2017-January","","","1","4","3","12","10.1109/IMOC.2017.8121122","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85043513559&doi=10.1109%2fIMOC.2017.8121122&partnerID=40&md5=bec8b71a5e7289533af540c776189538","Asso. Plasma Laboratory, National Institute for Space Research, Sao Jose dos Campos, Brazil; Electrical and Computer Engineering Dept., University of New Mexico, Albuquerque, United States; Division of Electronic Engineering, Technological Institute of Aeronautics, Sao Jose dos Campos, Brazil; Dept. of Electrical and Electronics Engineering, Gaziantep University, Gaziantep, Turkey","Rossi J.O., Asso. Plasma Laboratory, National Institute for Space Research, Sao Jose dos Campos, Brazil; Yamasaki F.S., Asso. Plasma Laboratory, National Institute for Space Research, Sao Jose dos Campos, Brazil; Schamiloglu E., Electrical and Computer Engineering Dept., University of New Mexico, Albuquerque, United States; Barroso J.J., Division of Electronic Engineering, Technological Institute of Aeronautics, Sao Jose dos Campos, Brazil; Hasar U.C., Dept. of Electrical and Electronics Engineering, Gaziantep University, Gaziantep, Turkey","Gyromagnetic nonlinear transmission lines are interesting new devices used for RF generation since they are all solid state, lightweight and compact, neither requiring vacuum nor thermionic filament as in electronic tubes. Experiments with these lines have demonstrated their successful operation at L and S bands, thereby enabling them for applications in UWB pulsed radars in space vehicles and defense systems. There is also a great interest in compact solid-state high-po wer microwave sources for applications in small defense platforms (boats, trucks, etc.) to destroy the enemy electronic systems. Although the operation of these devices has been demonstrated exhaustively in recent years, their working principle is not quite well understood so far as it has been expected that the precession of the magnetic dipoles in the ferrite material given by the Larmor frequency, which predicts a proportional increase with the magnetic field bias. However, as observed experimentally the opposite occurs and the frequency decreases with the increasing of the magnetic field applied. Thus, the objective of this paper is to address this problem using the Landau-Lifshitz-Gilbert (LLG) equation with boundary conditions on the TEM mode propagation in the coaxial line. The formulation obtained for the precession frequency will be used to compare with experimental data found in the literature. © 2017 IEEE.","Gyromagnetic effect; Magnetic precession; Nonlinearity; Transmission lines","Automobile electronic equipment; Electric lines; Magnetic fields; Magnetism; Network security; Optoelectronic devices; Thermionic tubes; Gyromagnetic effect; Landau-Lifshitz-Gilbert equations; Larmor frequencies; Magnetic precession; Nonlinear transmission lines; Nonlinearity; Operation analysis; Precession frequency; Magnetic levitation vehicles","","","","","","","Yamasaki F.S., Schamiloglu E., Rossi J.O., Barroso J.J., Simulation studies of distributed nonlinear gyromagnetic lines based on LC lumped model, IEEE Trans. Plasma Sci., 44, 10, pp. 2232-2239, (2016); Romanchenko I.V., Rostov V.V., Gubanov V.P., Stepchenko A.S., Gunin A.V., Kurkan I.K., Repetitive sub-gigawatt rf source based on gyromagnetic nonlinear transmission line, Rev. Sci. Intrum., 83, (2012); Reale D.V., Bragg J.-W.B., Gonsalves N.R., Johnson J.M., Neuber A.A., Dickens J.C., Mankowski J.J., Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines, Rev. Sci. Instrum., 85, (2014); Gilbert T.L., A phenomelogical theory of damping in ferromagnetic materilals, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Bragg J.-W.B., Dickens J.C., Neuber A.A., Material selection considerations for coaxial, ferrimagnetic-based nonlinear transmission lines, J. Appl. Phys., 113, (2013); Bragg J.-W.B., Sullivan W.W., Mauch D., Neuber A.A., Dickens J.C., All solid-state high power microwave source with high repetition frequency, Rev. Sci. Instrum., 84, (2013); Bragg J.-W.B., Simmons C., Dickens J.C., Neuber A.A., Serial arrangement of ferrimagnetic nonlinear transmission lines, IEEE Int. Power Modulator and High Voltage Conf., pp. 229-230, (2012); Romanchenko I.V., Rostov V.V., Gunin A.V., Konev V.Yu., High power microwave beam steering based on gyromagnetic nonlinear transmission lines, J. Appl. Phys., 117, (2015); Karelin S.Y., Krasovitsky V.B., Magda I.I., Mukhin V.S., Sinitsin V.G., RF oscillations in a coaxial transmission line with a saturated ferrite: 2-D simulation and experiment, Int. Conf. on Ultrawideb and and Ultrashort Impulse Signa Ls, pp. 60-63, (2016); Baden-Fuller A.J., Ferrites at Microwave Frequencies, (2005)","","","Institute of Electrical and Electronics Engineers Inc.","Anritsu; Brazilian Microwave and Optoelectronics Society (SBMO); CPqD; Keysight Technologies; Microwave Theory and Technique Society of the Institute of Electrical and Electronics Engineers (IEEE MTT-S)","17th SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference, IMOC 2017","27 August 2017 through 30 August 2017","A�guas de Lindoia","133381","","978-150906241-6","","","English","SBMO/IEEE MTT-S Int. Microw. Optoelectron. Conf., IMOC","Conference paper","Final","","Scopus","2-s2.0-85043513559" +"Sayed S.B.; Ulku H.A.; Bagci H.","Sayed, Sadeed B. (56441086800); Ulku, H. Arda (55667333000); Bagci, Hakan (24477237400)","56441086800; 55667333000; 24477237400","Transient analysis of scattering from ferromagnetic objects using Landau-Lifshitz-Gilbert and volume integral equations","2016","2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings","","","7696748","2083","2084","1","2","10.1109/APS.2016.7696748","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84997270717&doi=10.1109%2fAPS.2016.7696748&partnerID=40&md5=acf8e754f8f560489a0d64b616f0adf7","Division of Computer Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia; Department of Electronics Engineering, Gebze Technical University, Kocaeli, 41400, Turkey","Sayed S.B., Division of Computer Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia; Ulku H.A., Division of Computer Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia, Department of Electronics Engineering, Gebze Technical University, Kocaeli, 41400, Turkey; Bagci H., Division of Computer Electrical and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia","An explicit marching on-in-time scheme for analyzing transient electromagnetic wave interactions on ferromagnetic scatterers is described. The proposed method solves a coupled system of time domain magnetic field volume integral and Landau-Lifshitz-Gilbert (LLG) equations. The unknown fluxes and fields are discretized using full and half Schaubert-Wilton-Glisson functions in space and bandlimited temporal interpolation functions in time. The coupled system is cast in the form of an ordinary differential equation and integrated in time using a PE(CE)m type linear multistep method to obtain the unknown expansion coefficients. Numerical results demonstrating the stability and accuracy of the proposed scheme are presented. © 2016 IEEE.","","","","","","","","","Kobidze G., Shanker B., Integral equation based analysis of scattering from 3-D inhomogeneous anisotropic bodies, IEEE Trans. Antennas Propag., 52, pp. 2650-2658, (2004); Dib N., Omar A., Dispersion analysis of multilayer cylindrical transmission lines containing magnetized ferrite substrates, IEEE Trans. Microwave Theory Tech., 50, pp. 1730-1736, (2002); Schaubert D.H., Donald R.W., Allen W.G., A tetrahedral modeling method for electromagnetic scattering by arbitrarily shaped inhomogeneous dielectric bodies, IEEE Trans. Antennas Propag., 32, pp. 77-85, (1984); Kobidze G., Gao J., Shanker B., Michielssen E., A fast time domain integral equation based scheme for analyzing scattering from dispersive objects, IEEE Trans. Antennas Propag., 53, pp. 1215-1226, (2005); Ulku H.A., Bagci H., Michielssen E., Marching on-in-time solution of the time domain magnetic field integral equation using a predictorcorrector scheme, IEEE Trans. Antennas Propag., 61, pp. 4120-4131, (2013); Wildman R., Pisharody G., Weile D.S., Shanker B., Michielssen E., An accurate scheme for the solution of the time-domain integral equations of electromagnetics using higher order vector bases and bandlimited extrapolation, IEEE Trans. Antennas Propag., 52, pp. 2973-2984, (2004); Sayed S.B., Ulku H.A., Bagci H., A stable marching on-in-time scheme for solving the time domain electric field volume integral equation on high-contrast scatterers, IEEE Trans. Antennas Propag., 63, pp. 3098-3110, (2015); Glaser A., Rokhlin V., A new class of highly accurate solvers for ordinary differential equations, J. Sci. Comput., 38, pp. 368-399, (2009)","","","Institute of Electrical and Electronics Engineers Inc.","The Institute of Electrical and Electronics Engineers IEEE Antennas and Propagation Society","2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016","26 June 2016 through 1 July 2016","Fajardo","124461","","978-150902886-3","","","English","IEEE Antennas Propag. Soc. Int. Symp., APSURSI - Proc.","Conference paper","Final","","Scopus","2-s2.0-84997270717" +"Bailey W.E.","Bailey, William E. (57193036552)","57193036552","Magnetization Dynamics","2016","Introduction to Magnetic Random-Access Memory","","","","79","100","21","0","10.1002/9781119079415.ch4","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85019473687&doi=10.1002%2f9781119079415.ch4&partnerID=40&md5=81dab4588b32113dad454b101d68ad85","Materials Science and Engineering, Department of Applied Physics and Applied Mathematics, Columbia University, NY, United States","Bailey W.E., Materials Science and Engineering, Department of Applied Physics and Applied Mathematics, Columbia University, NY, United States","This chapter provides a concise introduction to magnetization dynamics in single magnetic domains, with an emphasis on behavior in ferromagnetic metal thin films. The material presented here underpins micromagnetics, which consists of coupled equations of motion for single magnetic domains, and spin torque, which adds additional terms to the equation of motion for a single domain. In Section 4.1, we provide motivation and formalism for the fundamental equation of motion of magnetization, the Landau-Lifshitz-Gilbert (LLG) equation. Small-angle solutions of the LLG equation are developed in Section 4.2.1. We emphasize how materials parameters have been extracted from experiments, particularly from ferromagnetic resonance experiments, in Section 4.2.2 and tabulate some materials parameters in Section 4.2.3. Approaches to calculate large-angle dynamics are developed in Section 4.3; we show quasistatic aspects of switching and a short example of how to integrate the nonlinear LLG equation for a switching experiment. Finally, in Section 4.4, we describe how spin torque terms modify the LLG equation and outline some simple consequences. © 2017 by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.","Ferromagnetic resonance; Landau-Lifshitz-Gilbert equation; Magnetization dynamics; Pulsed magnetization dynamics; Small-angle magnetization dynamics; Spin-transfer torque; Stoner-Wohlfarth model; Thermally activated switching","Dynamics; Equations of motion; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic domains; Nonlinear equations; Spin dynamics; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Pulsed magnetization; Spin transfer torque; Stoner-Wohlfarth model; Thermally activated; Magnetization","","","","","","","Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. Sowjet, 8, pp. 153-169, (1935); Brooks H., Ferromagnetic anisotropy and the itinerant electron model, Phys. Rev, 58, pp. 909-918, (1940); Crawford T., Silva T., Teplin C., Rogers C., Subnanosecond magnetization dynamics measured by the second-harmonic magneto-optic Kerr effect, Appl. Phys. Lett, 74, pp. 3386-3388, (1999); Liboff R., Introduction to Quantum Mechanics, 4, (2002); Einstein A., De Haas W., Experimental proof of Ampere's molecular currents, Verh. Dtsch. Phys. Ges, 17, pp. 152-170, (1915); Frenkel V.Y., On the history of the Einstein-de Haas effect, Sov. Phys. Usp, 22, pp. 580-584, (1979); Barnett S.J., Magnetization by rotation, Phys. Rev, 6, pp. 239-270, (1915); Barnett S., Kenny G., Gyromagnetic ratios of iron, cobalt and many binary alloys of iron, cobalt and nickel, Phys. Rev, 87, pp. 723-734, (1952); Gilbert T.L., Kelly J.M., Anomalous rotational damping in ferromagnetic sheets, Conference on Magnetism and Magnetic Materials, pp. 253-263, (1955); Gilbert T., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, pp. 3443-3449, (2004); Saslow W., Landau-Lifshitz or Gilbert damping? That is the question, J. Appl. Phys, 105, (2009); Meyer A., Asch G., Experimental g and g values of Fe, Co, Ni and their alloys, J. Appl. Phys, 32, pp. 330-333, (1961); Reck R.A., Fry D.L., Orbital and spin magnetization in Fe-Co, Fe-Ni, and Ni-Co, Phys. Rev, 184, pp. 492-495, (1969); Chapter III-13: Metals: Phonon States, Electron States, and Fermi Surfaces, pp. 100-101, (1990); Frait Z., Fraitova D., Ferromagnetic resonance and surface anisotropy in iron single crystals, J. Magn. Magn. Mater, 15-18, pp. 1081-1082, (1980); Schreiber F., Pflaum J., Frait Z., Muhge T., Pelzl J., Gilbert damping and g-factor in FexCo1 x alloy films, Solid State Commun, 93, pp. 965-968, (1995); Scheck C., Cheng L., Barsukov I., Frait Z., Bailey W., Low relaxation rate in epitaxial vanadium-doped ultrathin iron films, Phys. Rev. Lett, 98, (2007); Bhagat S., Lubitz P., Temperature dependence of ferromagnetic relaxation in the 3d transition metals, Phys. Rev. B, 10, pp. 179-185, (1974); Guan Y., Bailey W.E., Ferromagnetic relaxation in (Ni81Fe19)1 xCux thin films: band filling at high Z, J. Appl. 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Phys, 67, pp. 397-455, (1995); Zavoisky E., Paramagnetic relaxation of liquid solutions for perpendicular fields, J. Phys. USSR, 9, pp. 211-216, (1945); Purcell E.M., Torrey H.C., Pound R.V., Resonance absorption by nuclear magnetic moments in a solid, Phys. Rev, 69, pp. 37-38, (1946); Griffiths J., Anomalous high-frequency resistance in ferromagnetic metals, Nature, 158, pp. 670-671, (1946); Kittel C., Interpretation of anomalous Larmor frequencies in ferromagnetic resonance experiment, Phys. Rev, 71, pp. 270-271, (1947); McMichael R., Krivosik P., Classical model of extrinsic ferromagnetic resonance linewidth in ultrathin films, IEEE Trans. Magn, 40, pp. 2-11, (2004); Ament W., Rado G., Electromagnetic effects of spin wave resonance in ferromagnetic metals, Phys. Rev, 97, pp. 1558-1566, (1955); Gilmore K., Idzerda Y.U., Stiles M.D., Identification of the dominant precession-damping mechanism in Fe, Co, and Ni by first-principles calculations, Phys. Rev. Lett, 99, (2007); Fahnle M., Seib J., Illg C., Relating Gilbert damping and ultrafast laser-induced demagnetization, Phys. Rev. B, 82, (2010); Lock J., Eddy current damping in thin metallic ferromagnetic films, Br. J. Appl. Phys, 17, pp. 1645-1647, (1966); Scheck C., Cheng L., Bailey W., Low damping in epitaxial sputtered Fe films, Appl. Phys. Lett, 88, (2006); Patton C.E., Linewidth and relaxation processes for the main resonance in the spin-wave spectra of Ni-Fe alloy films, J. Appl. Phys, 39, pp. 3060-3068, (1968); Heinrich B., Urquhart K., Arrott A., Cochran J., Myrtle K., Purcell S., Ferromagnetic-resonance study of ultrathin BCC Fe(1 0 0) films grown epitaxially on FCC Ag(1 0 0) substrates, Phys. Rev. Lett, 59, pp. 1756-1759, (1987); Heinrich B., Spin relaxation in magnetic metallic layers and multilayers, Ultrathin Magnetic Structures III: Fundamentals of Nanomagnetism, pp. 143-210, (2005); Bendahan M., Canet P., Seguin J.-L., Carchano H., Control composition study of sputtered Ni-Ti shape memory alloy film, Mater. Sci. Eng. B, 34, pp. 112-115, (1995); Kittel C., On the gyromagnetic ratio and spectroscopic splitting factor of ferromagnetic substances, Phys. Rev, 76, pp. 743-748, (1949); Urban R., Woltersdorf G., Heinrich B., Gilbert damping in single and multilayer ultrathin films: role of interfaces in nonlocal spin dynamics, Phys. Rev. Lett, 87, (2001); Vaz C.A.F., Bland J.A.C., Lauhoff G., Magnetism in ultrathin film structures, Rep. Prog. Phys, 71, (2008); Neel L., Anisotropie magnétique superficielle et surstructures d'orientation, J. Phys. Radium, 15, pp. 225-239, (1954); Bailey G.C., Vittoria C., Presence of magnetic surface anisotropy in Permalloy films, Phys. Rev. B, 8, pp. 3247-3251, (1973); Rantschler J.O., Chen P.J., Arrott A.S., McMichael R.D., Egelhoff J.W.F., Maranville B.B., Surface anisotropy of Permalloy in NM/NiFe/NM multilayers, J. Appl. Phys, 97, (2005); Gambardella P., Rusponi S., Veronese M., Dhesi S.S., Grazioli C., Dallmeyer A., Cabria I., Zeller R., Dederichs P.H., Kern K., Carbone C., Brune H., Giant magnetic anisotropy of single cobalt atoms and nanoparticles, Science, 300, pp. 1130-1133, (2003); Beaujour J.-M., Lee J., Kent A., Krycka K., Kao C.-C., Magnetization damping in ultrathin polycrystalline Co films: evidence for nonlocal effects, Phys. Rev. B, 74, (2006); Nibarger J.P., Lopusnik R., Celinski Z., Silva T.J., Variation of magnetization and the Landé g factor with thickness in Ni-Fe films, Appl. Phys. Lett, 83, pp. 93-95, (2003); Tserkovnyak Y., Brataas A., Bauer G., Halperin B., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Rev. Mod. Phys, 77, pp. 1375-1421, (2005); Wolf P., Free oscillations of the magnetization in Permalloy films, J. Appl. Phys, 32, pp. S95-S96, (1961); Silva T., Lee C., Crawford T., Rogers C., Inductive measurement of ultrafast magnetization dynamics in thin-film Permalloy, J. Appl. Phys, 85, pp. 7849-7862, (1999); Kos A.B., Silva T.J., Kabos P., Pulsed inductive microwave magnetometer, Rev. Sci. Instrum, 73, pp. 3563-3569, (2002); Freeman M.R., Picosecond pulsed-field probes of magnetic systems, J. Appl. Phys, 75, pp. 6194-6198, (1994); Russek S.E., Kaka S., Donahue M., High-speed dynamics, damping, and relaxation times in submicrometer spin-valve devices, J. Appl. Phys, 87, pp. 7070-7073, (2000); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Philos. Trans. R. Soc. A, 240, pp. 599-642, (1948); Thiaville A., Extensions of the geometric solution of the two-dimensional coherent magnetization rotation model, J. Magn. Magn. Mater, 182, pp. 5-18, (1998); Neel L., Some theoretical aspects of rock-magnetism, Adv. Phys, 4, pp. 191-243, (1955); Wernsdorfer W., Orozco E.B., Hasselbach K., Benoit A., Barbara B., Demoncy N., Loiseau A., Pascard H., Mailly D., Experimental evidence of the Néel-Brown model of magnetization reversal, Phys. Rev. Lett, 78, pp. 1791-1794, (1997); Rizzo N.D., DeHerrera M., Janesky J., Engel B., Slaughter J., Tehrani S., Thermally activated magnetization reversal in submicron magnetic tunnel junctions for magnetoresistive random access memory, Appl. Phys. Lett, 80, pp. 2335-2337, (2002); Koch R.H., Grinstein G., Keefe G.A., Lu Y., Trouilloud P.L., Gallagher W.J., Parkin S.S.P., Thermally assisted magnetization reversal in submicron-sized magnetic thin films, Phys. Rev. Lett, 84, pp. 5419-5422, (2000); Sun J.Z., Slonczewski J.C., Trouilloud P.L., Abraham D., Bacchus I., Gallagher W.J., Hummel J., Lu Y., Wright G., Parkin S.S.P., Koch R.H., Thermal activation-induced sweep-rate dependence of magnetic switching astroid, Appl. Phys. Lett, 78, pp. 4004-4006, (2001); Sun J.Z., Spin-current interaction with a monodomain magnetic body: a model study, Phys. Rev. B, 62, pp. 570-578, (2000); Slonczewski J., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, pp. 1-7, (1996); Bazaliy Y.B., Jones B., Zhang S.-C., Modification of the Landau-Lifshitz equation in the presence of a spin-polarized current in colossal-and giant-magnetoresistive materials, Phys. Rev. B, 57, pp. R3213-R3216, (1998); Petit S., Baraduc C., Thirion C., Ebels U., Liu Y., Li M., Wang P., Dieny B., Spin-torque influence on the high-frequency magnetization fluctuations in magnetic tunnel junctions, Phys. Rev. Lett, 98, (2007); Petit S., de Mestier N., Baraduc C., Thirion C., Liu Y., Li M., Wang P., Dieny B., Influence of spin-transfer torque on thermally activated ferromagnetic resonance excitations in magnetic tunnel junctions, Phys. Rev. B, 78, (2008); Farle M., Ferromagnetic resonance of ultrathin metallic layers, Rep. Prog. Phys, 61, pp. 755-826, (1998); Russek S.E., McMichael R.D., Donahue M.J., Kaka S., High speed switching and rotational dynamics in small magnetic thin film devices, Spin Dynamics in Confined Magnetic Structures II, 87, pp. 93-154, (2003); Ralph D., Stiles M., Spin transfer torques, J. Magn. Magn. Mater, 320, pp. 1190-1216, (2008); Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2008)","","","Wiley-IEEE Press","","","","","","","978-111907941-5; 978-111900974-0","","","English","Introd. to Magn. Random-Access Mem.","Book chapter","Final","","Scopus","2-s2.0-85019473687" +"Kumar D.; Adeyeye A.O.","Kumar, D. (56746994400); Adeyeye, A.O. (7004047544)","56746994400; 7004047544","Techniques in micromagnetic simulation and analysis","2017","Journal of Physics D: Applied Physics","50","34","343001","","","","67","10.1088/1361-6463/aa7c04","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85027269786&doi=10.1088%2f1361-6463%2faa7c04&partnerID=40&md5=4b1a648c5e609da48873d8ece4b4e428","Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore","Kumar D., Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore; Adeyeye A.O., Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore","Advances in nanofabrication now allow us to manipulate magnetic material at micro- and nanoscales. As the steps of design, modelling and simulation typically precede that of fabrication, these improvements have also granted a significant boost to the methods of micromagnetic simulations (MSs) and analyses. The increased availability of massive computational resources has been another major contributing factor. Magnetization dynamics at micro- and nanoscale is described by the Landau-Lifshitz-Gilbert (LLG) equation, which is an ordinary differential equation (ODE) in time. Several finite difference method (FDM) and finite element method (FEM) based LLG solvers are now widely use to solve different kind of micromagnetic problems. In this review, we present a few patterns in the ways MSs are being used in the pursuit of new physics. An important objective of this review is to allow one to make a well informed decision on the details of simulation and analysis procedures needed to accomplish a given task using computational micromagnetics. We also examine the effect of different simulation parameters to underscore and extend some best practices. Lastly, we examine different methods of micromagnetic analyses which are used to process simulation results in order to extract physically meaningful and valuable information. © 2017 IOP Publishing Ltd.","magnetization dynamics; micromagnetic simulations; spin waves","Differential equations; Finite difference method; Magnetic logic devices; Magnetic materials; Magnetization; Multilayers; Nanotechnology; Ordinary differential equations; Spin dynamics; Spin waves; Computational resources; Finitedifference methods (FDM); Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Micromagnetic simulations; Modelling and simulations; Ordinary differential equation (ODE); Simulation and analysis; Finite element method","","","","","National Research Foundation Singapore, NRF, (NRF-CRP 10-2012-03)","This work was supported by National Research Foundation, Prime Minister's Office, Singapore under its Competitive Research Programme (CRP Award No. NRF-CRP 10-2012-03).","Brown W., Micromagnetics Interscience Tracts on Physics and Astronomy, (1963); Landau L.D., Lifshitz E.M., Phys. 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Rev., 91, (2015)","","","Institute of Physics Publishing","","","","","","00223727","","JPAPB","","English","J Phys D","Review","Final","","Scopus","2-s2.0-85027269786" +"Taniguchi T.; Kubota H.","Taniguchi, Tomohiro (36180180300); Kubota, Hitoshi (35248482000)","36180180300; 35248482000","Instability analysis of spin-torque oscillator with an in-plane magnetized free layer and a perpendicularly magnetized pinned layer","2016","Physical Review B","93","17","","","","","29","10.1103/PhysRevB.93.174401","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84966289647&doi=10.1103%2fPhysRevB.93.174401&partnerID=40&md5=903085ffeed958a64464e0929071080f","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan; Kubota H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","We study the theoretical conditions to excite a stable self-oscillation in a spin-torque oscillator with an in-plane magnetized free layer and a perpendicularly magnetized pinned layer in the presence of magnetic field pointing in an arbitrary direction. The linearized Landau-Lifshitz-Gilbert (LLG) equation is found to be inapplicable to evaluate the threshold between the stable and self-oscillation states because the critical current density estimated from the linearized equation is considerably larger than that found in the numerical simulation. We derive a theoretical formula of the threshold current density by focusing on the energy gain of the magnetization from the spin torque during a time shorter than a precession period. A good agreement between the derived formula and the numerical simulation is obtained. The condition to stabilize the out-of-plane self-oscillation above the threshold is also discussed. © 2016 American Physical Society.","","","","","","","","","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., Phys. Rev. B, 71, (2005); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. 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B","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-84966289647" +"Preobrazhensky V.; Klimov A.; Tiercelin N.; Dusch Y.; Giordano S.; Churbanov A.; Mathurin T.; Pernod P.; Sigov A.","Preobrazhensky, Vladimir (7004493603); Klimov, Alexey (35391085300); Tiercelin, Nicolas (6603515103); Dusch, Yannick (37107392200); Giordano, Stefano (56242214600); Churbanov, Anton (56856803700); Mathurin, Theo (57190278501); Pernod, Philippe (7003429648); Sigov, Alexander (35557510600)","7004493603; 35391085300; 6603515103; 37107392200; 56242214600; 56856803700; 57190278501; 7003429648; 35557510600","Dynamics of the stress-mediated magnetoelectric memory cell N×(TbCo2/FeCo)/PMN-PT","2018","Journal of Magnetism and Magnetic Materials","459","","","66","70","4","12","10.1016/j.jmmm.2017.12.028","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85039445816&doi=10.1016%2fj.jmmm.2017.12.028&partnerID=40&md5=d50bb4f4ca2c69997ad52189e2bfefc0","Joint International Laboratory LIA LICS: Wave Research Center, A.M. Prokhorov GPI, RAS, ul. Vavilova 38, Moscow, 119991, Russian Federation; Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Joint International Laboratory LIA LICS: Moscow Technological University (MIREA), Vernadsky Avenue 78, Moscow, 119454, Russian Federation; Joint International Laboratory LIA LICS: V. A. Kotel'nikov Inst. of Radioeng. and Electronics (IRE RAS), ul. Mokhovaya 11/7, Moscow, 125009, Russian Federation; Moscow Institute of Physics and Technology, Dolgoprudny, Institutskiy Lane, 9, 141700, Russian Federation","Preobrazhensky V., Joint International Laboratory LIA LICS: Wave Research Center, A.M. Prokhorov GPI, RAS, ul. Vavilova 38, Moscow, 119991, Russian Federation, Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Klimov A., Joint International Laboratory LIA LICS: Moscow Technological University (MIREA), Vernadsky Avenue 78, Moscow, 119454, Russian Federation, Joint International Laboratory LIA LICS: V. A. Kotel'nikov Inst. of Radioeng. and Electronics (IRE RAS), ul. Mokhovaya 11/7, Moscow, 125009, Russian Federation; Tiercelin N., Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Dusch Y., Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Giordano S., Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Churbanov A., Joint International Laboratory LIA LICS: V. A. Kotel'nikov Inst. of Radioeng. and Electronics (IRE RAS), ul. Mokhovaya 11/7, Moscow, 125009, Russian Federation, Moscow Institute of Physics and Technology, Dolgoprudny, Institutskiy Lane, 9, 141700, Russian Federation; Mathurin T., Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Pernod P., Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; Sigov A., Joint International Laboratory LIA LICS: Moscow Technological University (MIREA), Vernadsky Avenue 78, Moscow, 119454, Russian Federation","Stress-mediated magnetoelectric heterostructures represent a very promising approach for the realization of ultra-low energy Random Access Memories. The magnetoelectric writing of information has been extensively studied in the past, but it was demonstrated only recently that the magnetoelectric effect can also provide means for reading the stored information. We hereby theoretically study the dynamic behaviour of a magnetoelectric random access memory cell (MELRAM) typically composed of a magnetostrictive multilayer N×(TbCo2/FeCo) that is elastically coupled with a 〈0 1 1〉 PMN-PT ferroelectric crystal and placed in a Wheatstone bridge-like configuration. The numerical resolution of the LLG and electrodynamics equation system demonstrates high speed write and read operations with an associated extra-low energy consumption. In this model, the reading energy for a 50 nm cell size is estimated to be less than 5 aJ/bit. © 2017 Elsevier B.V.","Extra-low energy; Magnetoelectric memory; Magnetoelectric readout; MELRAM; Straintronics","Dynamic random access storage; Energy utilization; Memory architecture; Semiconductor storage; Extra-low energy; Ferroelectric crystal; Low energy consumption; Magnetoelectric readout; MELRAM; Numerical resolution; Random access memory; Straintronics; Random access storage","","","","","","","ITRS, (2013); Chen A., A review of emerging non-volatile memory (nvm) technologies and applications, Solid-State Electron., 125, pp. 25-38, (2016); Tiercelin N., Dusch Y., Preobrazhensky V., Pernod P., Magnetoelectric memory using orthogonal magnetization states and magnetoelastic switching, J. Appl. Phys., 109, 7, (2011); Tiercelin N., Dusch Y., Klimov A., Giordano S., Preobrazhensky V., Pernod P., Room temperature magnetoelectric memory cell using stress-mediated magnetoelastic switching in nanostructured multilayers, Appl. Phys. Lett., 99, 19, pp. 192507-192513, (2011); Hu J.-M., Li Z., Chen L.-Q., Nan C.-W., High-density magnetoresistive random access memory operating at ultralow voltage at room temperature, Nat. Commun., 2, (2011); Wu T., Bur A., Wong K., Zhao P., Lynch C.S., Amiri P.K., Wang K.L., Carman G.P., Electrical control of reversible and permanent magnetization reorientation for magnetoelectric memory devices, Appl. Phys. Lett., 98, 26, (2011); Ghidini M., Pellicelli R., Prieto J., Moya X., Soussi J., Briscoe J., Dunn S., Mathur N., Non-volatile electrically-driven repeatable magnetization reversal with no applied magnetic field, Nat. Commun., 4, (2013); Biswas A.K., Bandyopadhyay S., Atulasimha J., Complete magnetization reversal in a magnetostrictive nanomagnet with voltage-generated stress: a reliable energy-efficient non-volatile magneto-elastic memory, Appl. Phys. Lett., 105, 7, (2014); Biswas A.K., Ahmad H., Atulasimha J., Bandyopadhyay S., Experimental demonstration of complete 180° reversal of magnetization in isolated Co nanomagnets on a PMN-PT substrate with voltage generated strain, Nano Lett., (2017); Boomgaard J.V.D., van Run A.M.J.G., Van Suchtelen J., Piezoelectric-piezomagnetic composites with magnetoelectric effect, Ferroelectrics, 14, 1, pp. 727-728, (1976); Roy K., Bandyopadhyay S., Atulasimha J., Hybrid spintronics and straintronics: A magnetic technology for ultra low energy computing and signal processing, Appl. Phys. Lett., 99, 6, (2011); Biswas A.K., Bandyopadhyay S., Atulasimha J., Energy-efficient magnetoelastic non-volatile memory, Appl. Phys. Lett., 104, 23, (2014); Giordano S., Dusch Y., Tiercelin N., Pernod P., Preobrazhensky V., Combined nanomechanical and nanomagnetic analysis of magnetoelectric memories, Phys. Rev. B, 85, 15, (2012); Giordano S., Dusch Y., Tiercelin N., Pernod P., Preobrazhensky V., Thermal effects in magnetoelectric memories with stress-mediated switching, J. Phys. D: Appl. Phys., 46, 32, (2013); Tiercelin N., Dusch Y., Giordano S., Klimov A., Preobrazhensky V., Pernod P., (2015); Zhao Z., Jamali M., D'Souza N., Zhang D., Bandyopadhyay S., Atulasimha J., Wang J.-P., Giant voltage manipulation of mgo-based magnetic tunnel junctions via localized anisotropic strain: a potential pathway to ultra-energy-efficient memory technology, Appl. Phys. Lett., 109, 9, (2016); Lei N., Devolder T., Agnus G., Aubert P., Daniel L., Kim J.V., Zhao W., Trypiniotis T., Cowburn R.P., Chappert C., Ravelosona D., Lecoeur P., Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures, Nat. Commun., 4, (2013); Roy K., Separating read and write units in multiferroic devices, Sci. Rep., 5, (2015); Roy K., Ultralow energy analog straintronics using multiferroic composites, IEEE Trans. Nanotechnol., 16, 2, pp. 333-346, (2017); Dusch Y., Rudenko V., Tiercelin N., Giordano S., Preobrazhensky V., Pernod P., Hysteretic magnetoresistance in stress controlled magnetic memory device, Nanomater. Nanostruct., 2, pp. 44-50, (2012); Klimov A., Tiercelin N., Dusch Y., Giordano S., Mathurin T., Pernod P., Preobrazhensky V., Churbanov A., Nikitov S., Magnetoelectric write and read operations in a stress-mediated multiferroic memory cell, Appl. Phys. Lett., 110, 22, (2017); Tiercelin N., Dusch Y., Preobrazhensky V., Pernod P.; Dusch Y., Tiercelin N., Klimov A., Giordano S., Preobrazhensky V., Pernod P., Stress-mediated magnetoelectric memory effect with uni-axial tbco2/feco multilayer on 011-cut pmn-pt electrostrictive material, J. Appl. Phys., 113, (2013); Tiercelin N., Preobrazhensky V., Pernod P., Ostaschenko A., Enhanced magnetoelectric effect in nanostructured magnetostrictive thin film resonant actuator with field induced spin reorientation transition, Appl. Phys. Lett., 92, 6, pp. 062904-062913, (2008); Tiercelin N., Talbi A., Preobrazhensky V., Pernod P., Mortet V., Haenen K., Soltani A., Magnetoelectric effect near spin reorientation transition in giant magnetostrictive-aluminum nitride thin film structure, Appl. Phys. Lett., 93, 16, pp. 162902-162903, (2008); Wang F., Luo L., Zhou D., Zhao X., Luo H., Complete set of elastic, dielectric, and piezoelectric constants of orthorhombic (0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3) single crystal, Appl. Phys. Lett., 90, 21, pp. 212903-212913, (2007); Kkay A., Varga L.K., Monodomain critical radius for soft-magnetic fine particles, J. Appl. Phys., 97, (2005); Giordano S., Dusch Y., Tiercelin N., Pernod P., Preobrazhensky V., Stochastic magnetization dynamics in single domain particles, Eur. Phys. J. B, 66, (2013); Sun J.Z., Spin-transfer torque switched magnetic tunnel junctions in magnetic random access memory, Proc. SPIE, 9931, pp. 1-13, (2016); Zhao W., Devolder T., Lakys Y., Klein J., Chappert C., Mazoyer P., Design considerations and strategies for high-reliable STT-MRAM, Microelectron. Reliab., 51, 9-11, pp. 1454-1458, (2011)","N. Tiercelin; Joint International Laboratory LIA LICS: Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520 – IEMN, Lille, F-59651, France; email: nicolas.tiercelin@iemn.univ-lille1.fr","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85039445816" +"Yao Z.; Cui H.; Itoh T.; Wang Y.E.","Yao, Zhi (56380891100); Cui, Han (55774086800); Itoh, Tatsuo (57208460042); Wang, Yuanxun Ethan (57202387207)","56380891100; 55774086800; 57208460042; 57202387207","Multiphysics Time-Domain Modeling of Nonlinear Permeability in Thin-film Magnetic Material","2018","IEEE MTT-S International Microwave Symposium Digest","2018-June","","8439540","208","211","3","2","10.1109/MWSYM.2018.8439540","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85053060517&doi=10.1109%2fMWSYM.2018.8439540&partnerID=40&md5=47dca5ddd34824f37a78e4a0a2296dc7","University of Califonia, Los Angeles, United States","Yao Z., University of Califonia, Los Angeles, United States; Cui H., University of Califonia, Los Angeles, United States; Itoh T., University of Califonia, Los Angeles, United States; Wang Y.E., University of Califonia, Los Angeles, United States","A fast-converging one-dimensional (1-D) finite-difference time-domain (FDTD) algorithm has been proposed based on reduction strategy of unknowns in electromagnetic (EM) fields. The proposed algorithm solves simultaneously Max-well's equations and Landau-Lifshitz-Gilbert (LLG) equation with nonlinear effects. Therefore, the proposed algorithm can predict the dynamic interaction between magnetic spins and EM fields. The accuracy of the modeling has been validated by 1. a standard magnetic switching process under static magnetic fields, and 2. the dispersive permeability of a PEe-backed continuous ferrite film with a 3 μ m-thickness, under dynamic electric excitation. The simulated permeability agrees with the theoretical prediction, under both linear and nonlinear circumstances. Specifically, the algorithm has fully revealed numerically that sufficiently large RF power can decrease the ferromagnetic resonance (FMR) frequency and suppress the permeability. © 2018 IEEE.","electromagnetics; ferrite; ferromagnetic; finite difference time domain methods; magnetics; multiphysics; nonlinear problems; thin films","Electric excitation; Ferrite; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Nonlinear equations; Thin films; Time domain analysis; Electromagnetics; ferromagnetic; magnetics; Multi-physics; Nonlinear problems; Finite difference time domain method","","","","","","","Wu M., Hoffmann A., Et al., Solid State Physics, 64, (2013); Harris V.G., Modern microwave ferrites, IEEE Trans. Magnetics, 48, 3, pp. 1075-1104, (2012); Lax B., Button K.J., Microwave Ferrites and Ferrimagnetics, (1962); Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proceedings of the IRE, 44, 10, pp. 1270-1284, (1956); Orth R.W., Frequency-selective limiters and their application, IEEE Trans. Electromagn. Compat, EMC-10, 2, pp. 273-283, (1968); Adam J.D., Stitzer S.N., A magnetostatic wave signal-to-noise enhancer, Applied Physics Letters, 36, 6, pp. 485-487, (1980); Kronmuller H., Parkin S., Handbook of Magnetism and Advanced Magnetic Materials, (2007); Yao Z., Wang Y.E., 3D unconditionally stable FDTD modeling of micromagnetics and electrodynamics, Microwave Symposium (IMS), 2017 IEEE MTT-S International, pp. 12-15, (2017); McMichael R.D., Et al., Switching dynamics and critical behavior of standard problem 4, Journal of Applied Physics, 89, 11, pp. 7603-7605, (2001); Zheng F., Chen Z., Zhang J., Toward the development of a threedimensional unconditionally stable finite-difference time-domain method, Microwave Theory and Techniques, IEEE Transactions on, 48, 9, pp. 1550-1558, (2000)","","","Institute of Electrical and Electronics Engineers Inc.","","2018 IEEE/MTT-S International Microwave Symposium, IMS 2018","10 June 2018 through 15 June 2018","Philadelphia","138766","0149645X","978-153865067-7","IMIDD","","English","IEEE MTT S Int Microwave Symp Dig","Conference paper","Final","","Scopus","2-s2.0-85053060517" +"Mondal R.; Berritta M.; Oppeneer P.M.","Mondal, Ritwik (56594584000); Berritta, Marco (35338853000); Oppeneer, Peter M (7004167024)","56594584000; 35338853000; 7004167024","Generalisation of Gilbert damping and magnetic inertia parameter as a series of higher-order relativistic terms","2018","Journal of Physics Condensed Matter","30","26","265801","","","","38","10.1088/1361-648X/aac5a2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85048954743&doi=10.1088%2f1361-648X%2faac5a2&partnerID=40&md5=5cd3a1769902c6c5aa7d8e73abeff6c2","Department of Physics and Astronomy, Uppsala University, PO Box 516, Uppsala, SE-751 20, Sweden","Mondal R., Department of Physics and Astronomy, Uppsala University, PO Box 516, Uppsala, SE-751 20, Sweden; Berritta M., Department of Physics and Astronomy, Uppsala University, PO Box 516, Uppsala, SE-751 20, Sweden; Oppeneer P.M., Department of Physics and Astronomy, Uppsala University, PO Box 516, Uppsala, SE-751 20, Sweden","The phenomenological Landau-Lifshitz-Gilbert (LLG) equation of motion remains as the cornerstone of contemporary magnetisation dynamics studies, wherein the Gilbert damping parameter has been attributed to first-order relativistic effects. To include magnetic inertial effects the LLG equation has previously been extended with a supplemental inertia term; the arising inertial dynamics has been related to second-order relativistic effects. Here we start from the relativistic Dirac equation and, performing a Foldy-Wouthuysen transformation, derive a generalised Pauli spin Hamiltonian that contains relativistic correction terms to any higher order. Using the Heisenberg equation of spin motion we derive general relativistic expressions for the tensorial Gilbert damping and magnetic inertia parameters, and show that these tensors can be expressed as series of higher-order relativistic correction terms. We further show that, in the case of a harmonic external driving field, these series can be summed and we provide closed analytical expressions for the Gilbert and inertial parameters that are functions of the frequency of the driving field. © 2018 IOP Publishing Ltd.","Gilbert damping; Landau-Lifshitz-Gilbert dynamics; magnetic inertial dynamics; relativistic magnetization dynamics; spin-orbit coupling","Damping; Dynamics; Equations of motion; Linear equations; Magnetization; Relativity; Gilbert damping; Inertial dynamics; Landau-Lifshitz-Gilbert; Magnetization dynamics; Spin-orbit couplings; article; motion; Spin dynamics","","","","","European Union’s Horizon2020 Research and Innovation Programme, (737709); Horizon 2020 Framework Programme, H2020, (737093); Knut och Alice Wallenbergs Stiftelse, (2015.0060); Vetenskapsrådet, VR","We thank PA Hervieux for valuable discussions. This work has been supported by the Swedish Research Council (VR), the Knut and Alice Wallenberg Foundation (Contract No. 2015.0060), the European Union’s Horizon2020 Research and Innovation Programme under grant agreement No. 737709 (FEMTOTERABYTE, www.physics.gu.se/femtoterabyte).","Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, pp. 101-114, (1935); Gilbert T.L., IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Gilbert T.L., Formulation, Foundations and Applications of the Phenomenological Theory of Ferromagnetism, (1956); Lakshmanan M., Phil. Trans. R. Soc., 369, pp. 1280-1300, (2011); Wegrowe J.E., Ciornei M.C., Am. J. Phys., 80, pp. 607-611, (2012); Olive E., Lansac Y., Meyer M., Hayoun M., Wegrowe J.E., J. Appl. Phys., 117, (2015); Wegrowe J.E., Olive E., J. Phys.: Condens. Matter, 28, 10, (2016); Ciornei M.C., Rubi J.M., Wegrowe J.E., Phys. Rev., 83, (2011); Kimel A.V., Ivanov B.A., Pisarev R.V., Usachev P.A., Kirilyuk A., Rasing T., Nat. Phys., 5, pp. 727-731, (2009); Bhattacharjee S., Nordstrom L., Fransson J., Phys. Rev. Lett., 108, (2012); Fahnle M., Steiauf D., Illg C., Phys. Rev., 84, (2011); Kunes J., Kambersky V., Phys. Rev., 65, (2002); Pelzl J., Meckenstock R., Spoddig D., Schreiber F., Pflaum J., Frait Z., J. Phys.: Condens. Matter, 15, 5, (2003); Hickey M.C., Moodera J.S., Phys. Rev. Lett., 102, (2009); He P., Ma X., Zhang J.W., Zhao H.B., Lupke G., Shi Z., Zhou S.M., Phys. Rev. Lett., 110, (2013); Kambersky V., Can. J. Phys., 48, (1970); Kambersky V., Czech. J. Phys., 26, pp. 1366-1383, (1976); Kambersky V., Phys. Rev., 76, (2007); Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 101, (2008); Fahnle M., Illg C., J. Phys.: Condens. Matter, 23, 49, (2011); Fahnle M., Steiauf D., Illg C., Phys. Rev., 88, (2013); Thonig D., Eriksson O., Pereiro M., Sci. Rep., 7, (2017); Mondal R., Berritta M., Oppeneer P.M., Phys. Rev., 94, (2016); Mondal R., Berritta M., Nandy A.K., Oppeneer P.M., Phys. Rev., 96, (2017); Mondal R., Berritta M., Carva K., Oppeneer P.M., Phys. Rev., 91, (2015); Mondal R., Relativisitic Theory of Laser-induced Magnetization Dynamics, (2017); Dirac P.A.M., Proc. Roy. Soc., 117, 778, pp. 610-624, (1928); Strange P., Relativistic Quantum Mechanics: With Applications in Condensed Matter and Atomic Physics, (1998); Foldy L.L., Wouthuysen S.A., Phys. Rev., 78, pp. 29-36, (1950); Silenko A.J., Phys. Rev., 94, (2016); Schwabl F., Hilton R., Lahee A., Advanced Quantum Mechanics, (2008); Silenko A.Y., Theor. Math. Phys., 176, pp. 987-999, (2013); Silenko A.J., Phys. Rev., 93, (2016); Eriksen E., Phys. Rev., 111, pp. 1011-1016, (1958); De Vries E., Jonker J., Nucl. Phys., 6, pp. 213-225, (1968); Hinschberger Y., Hervieux P.A., Phys. Lett., 376, pp. 813-819, (2012); Zawadzki W., Am. J. Phys., 73, pp. 756-758, (2005); Mondal R., Berritta M., Paillard C., Singh S., Dkhil B., Oppeneer P.M., Bellaiche L., Phys. Rev., 92, (2015); Mondal R., Berritta M., Oppeneer P.M., J. Phys.: Condens. Matter, 29, 19, (2017); Paillard C., Mondal R., Berritta M., Dkhil B., Singh S., Oppeneer P.M., Bellaiche L., Proc. SPIE, 9931, (2016)","R. Mondal; Department of Physics and Astronomy, Uppsala University, Uppsala, PO Box 516, SE-751 20, Sweden; email: ritwik.mondal@physics.uu.se","","Institute of Physics Publishing","","","","","","09538984","","JCOME","29771242","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85048954743" +"Jin F.; Li J.; Zhou L.; Peng J.; Chen H.","Jin, F. (54910501300); Li, J. (56943524100); Zhou, L. (58435369400); Peng, J. (57214868437); Chen, H. (57201979786)","54910501300; 56943524100; 58435369400; 57214868437; 57201979786","Simulation of Giant Magnetic-Impedance Effect in Co-Based Amorphous Films with Demagnetizing Field","2015","IEEE Transactions on Magnetics","51","11","07118708","","","","6","10.1109/TMAG.2015.2437816","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84946230286&doi=10.1109%2fTMAG.2015.2437816&partnerID=40&md5=680b7c9dfc3d9af8ba962779f3ba56ce","School of Automation, China University of Geosciences, Wuhan, 430074, China","Jin F., School of Automation, China University of Geosciences, Wuhan, 430074, China; Li J., School of Automation, China University of Geosciences, Wuhan, 430074, China; Zhou L., School of Automation, China University of Geosciences, Wuhan, 430074, China; Peng J., School of Automation, China University of Geosciences, Wuhan, 430074, China; Chen H., School of Automation, China University of Geosciences, Wuhan, 430074, China","The giant magnetic-impedance (GMI) effect in FeCoSiB thin films was investigated. By introducing the role of demagnetizing field, based on linear Maxwell's equations and Landau-Lifshitz-Gilbert (LLG) equation, the expressions of permeability and impedance were obtained and the theoretical model in this paper was significantly improved. A numerical simulation was conducted using MATLAB. For the thickness of thin film being close to the skin depth when the frequency of alternating current was up to megahertz, it could be found that the calculation results could match the experimental data very well when the thickness of the FeCoSiB thin film was greater than skin depth, while when the thin film thickness was less than skin depth, the calculation results had a big distortion. The influence of the demagnetization factor of FeCoSiB thin films on the GMI effect was also researched. This work was a tentative research on the simulation of the GMI effect of thin films. It might provide an attempt on the theoretical calculation of the GMI effect of thin films and guidance for the fabrication of thin-film GMI sensors. © 1965-2012 IEEE.","Demagnetizing field; FeCoSiB thin film; GMI effect; Numerical Simulation","Amorphous films; Computer simulation; Film thickness; Iron compounds; MATLAB; Maxwell equations; Mechanical permeability; Numerical models; Silicon compounds; Demagnetization factors; Demagnetizing field; Fabrication of thin films; Giant magnetic impedances; GMI effects; Landau-Lifshitz-Gilbert equations; Theoretical calculations; Theoretical modeling; Thin films","","","","","National Natural Science Foundation of China, (41004079)","","Mohri K., Kohsawa T., Kawashima K., Yoshida H., Panina L.V., Magneto-inductive effect (MI effect) in amorphous wires, IEEE Trans. Magn., 28, 5, pp. 3150-3152, (1992); Ge F.D., Ku W.J., Zhu J., Numerical study on giant magneto impedance effects in soft magnetic ribbons, J. Funct. Mater. Devices, 4, 2, pp. 49-54, (1997); Kraus L., The theoretical limits of giant magneto-impedance, J. Magn. Magn. Mater., 196, pp. 354-356, (1999); Phan M.-H., Peng H.-X., Giant magnetoimpedance materials: Fundamentals and applications, Prog. Mater. Sci., 53, 2, pp. 323-420, (2008); Ciureanu P., Melo L.G.C., Seddaoui D., Menard D., Yelon A., Physical models of magnetoimpedance, J. Appl. Phys., 102, 7, (2007); Jin F., Zhou L., Cheng W., Zhang Y., Tong B., Xu Y., Effect of shape and annealing on the giant magnetoimpendence properties of FeCoSiB ribbon, IEEE Trans. Magn., 50, 10, (2014); Zhou L., Jin F., Cheng W., Zhang Y., Simulation of giant magnetic impedance (GMI) effect in Co-based amorphous ribbons with demagnetizing field, J. Supercond. Novel Magn., 27, 7, pp. 1769-1775, (2014); Kittel C., Theory of the dispersion of magnetic permeability in ferromagnetic materials at microwave frequencies, Phys. Rev., 70, 5-6, pp. 281-290, (1946); Li M., Analysis of Giant Magneto-impedance Effect and Technical Magnetization Based on Amorphous Co-based Wire, (2007); Bao B.-H., Song X.-F., Ren N.-F., Li C.-S., Theory and calculation of giant magneto-impedance effect in amorphous alloy ribbons and films, Acta Phys. Sinica, 55, 7, pp. 3698-3704, (2006); Chen L., Giant Magnetoimpedance Effect of Soft Magnetic Materials and Its Appliation in Biosensing Field, (2011); Uchiyama T., Mohri K., Panina L.V., Furuno K., Magnetoimpedance in sputtered amorphous films for micro magnetic sensor, IEEE Trans. Magn., 31, 6, pp. 3182-3184, (1995); Garca D., Muoz J.L., Kurlyandskaya G., Vzquez M., Ali M., Gibbs M.R.J., Induced anisotropy, magnetic domain structure and magnetoimpedance effect in CoFeB amorphous thin films, J. Magn. Magn. Mater., 191, 3, pp. 339-344, (1999)","F. Jin; School of Automation, China University of Geosciences, Wuhan, 430074, China; email: jinfang78@cug.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84946230286" +"Mondal R.; Berritta M.; Nandy A.K.; Oppeneer P.M.","Mondal, Ritwik (56594584000); Berritta, Marco (35338853000); Nandy, Ashis K. (57213393607); Oppeneer, Peter M. (7004167024)","56594584000; 35338853000; 57213393607; 7004167024","On the origin of magnetic inertia: A rigorous relativistic Dirac theory derivation","2018","Proceedings of SPIE - The International Society for Optical Engineering","10732","","107322E","","","","1","10.1117/12.2323968","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85055568846&doi=10.1117%2f12.2323968&partnerID=40&md5=2b88fc927d6eb0b507695874213549f2","Fachbereich Physik, Universitat Konstanz, Konstanz, DE-78457, Germany; Department of Physics and Astronomy, Uppsala University, Box-516, Uppsala, SE-75120, Sweden","Mondal R., Fachbereich Physik, Universitat Konstanz, Konstanz, DE-78457, Germany; Berritta M., Department of Physics and Astronomy, Uppsala University, Box-516, Uppsala, SE-75120, Sweden; Nandy A.K., Department of Physics and Astronomy, Uppsala University, Box-516, Uppsala, SE-75120, Sweden; Oppeneer P.M., Department of Physics and Astronomy, Uppsala University, Box-516, Uppsala, SE-75120, Sweden","Inertia is a fundamental property of a particle that can be understood from Newtons laws of motion. In a similar way, any magnetized body must possess magnetic inertia by the virtue of its magnetization. The influence of possible magnetic inertia effects has recently drawn attention in ultrafast magnetization dynamics and switching. Magnetization dynamics at the inertial regime has been investigated using thermodynamic theories that predicted the magnetic inertia can become impactful at shorter timescales. However, at the fundamental level, the origin of magnetic inertial dynamics is still unknown. Here, we derive rigorously a description of magnetic inertia in the extended Landau-Lifshitz-Gilbert (LLG) equation starting from a fundamental and relativistic Dirac-Kohn-Sham framework. We use a unitary transformation, the so called called Foldy-Wouthuysen transformation, up to the order of 1/c4. In this way, the particle and anti-particle in fully relativistic description become decoupled and a Hamiltonian describing only the particles is derived. This Hamiltonian involves the nonrelativistic Schrodinger-Pauli Hamiltonian together with the relativistic corrections of the order 1/c2 and 1/c4. With the thus-derived Hamiltonian, we calculate the corresponding spin dynamics leading to the LLG equation of motion. Our result exemplify that the relativistic correction terms of 1/c2 are responsible for the Gilbert damping, however, the relativistic correction terms of 1/c4 are responsible for magnetic inertial dynamics. Therefore, we predict that the intrinsic magnetic inertia is a higher-order relativistic spin-orbit coupling effect and is expected to be prominent only on ultrashort timescales (subpicoseconds). We also show that the corresponding Gilbert damping and magnetic inertia parameters are related to one another through the imaginary and real parts of the magnetic susceptibility tensor, respectively. © 2018 SPIE.","Gilbert damping; Magnetic inertia; Magnetization dynamics; Relativistic theory; Spin-Orbit interaction","Damping; Equations of motion; Hamiltonians; Magnetic susceptibility; Magnetization; Spin dynamics; Gilbert damping; Magnetic inertia; Magnetization dynamics; Relativistic theory; Spin orbit interactions; Magnetic bubbles","","","","","A. Wallenberg Foundation, (2015.0060); European Community’s Seventh Framework Program; FP7/2007, (281043); Horizon 2020 Framework Programme, H2020, (737709); Vetenskapsrådet, VR","R. M. thanks Prof. Ulrich Nowak for fruitful discussions and travel support to attend the conference SPIE Optics+Photonics 2018 at San Diego. We acknowledge support by the European Community’s Seventh Framework Program (FP7/2007-2013) under Grant Agreement No. 281043, “FemtoSpin”, the Swedish Research Council (VR), and the K. and A. Wallenberg Foundation (Grant No. 2015.0060), the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 737709 (FEMTOTERABYTE, https://www.physics.gu.se/femtoterabyte).","Walker G.W., On the electric resistance to the motion of a charged conducting sphere in free space or in a field of force, Proc. Roy. Soc. London A, 77, 517, pp. 260-273, (1906); Walker G.W., The initial accelerated motion of electrified systems of finite extent, the reaction produced by the resulting radiation, Phil. Trans. Roy. Soc. A, 210, 463, pp. 145-197, (1911); Walker G.W., On magnetic inertia, Proc. Roy. Soc. London A, 93, 653, pp. 442-447, (1917); Cho S.Y., Spin nutation and polarization in ballistic semiconductor nanostructures, Phys. Rev. B, 77, (2008); Kimel A.V., Ivanov B.A., Pisarev R.V., Usachev P.A., Kirilyuk A., Rasing T., Inertia-driven spin switching in antiferromagnets, Nature Phys., 5, pp. 727-731, (2009); Goldstein H., Poole C.P., Safko J.L., [Classical Mechanics], (2002); Wegrowe J.-E., Ciornei M.-C., Magnetization dynamics, gyromagnetic relation, inertial effects, Am. J. Phys., 80, 7, pp. 607-611, (2012); Kikuchi T., Tatara G., Spin dynamics with inertia in metallic ferromagnets, Phys. Rev. B, 92, (2015); Wegrowe J.-E., Olive E., The magnetic monopole and the separation between fast and slow magnetic degrees of freedom, J. of Phys.: Condens. Matter, 28, 10, (2016); Olive E., Lansac Y., Meyer M., Hayoun M., Wegrowe J.-E., Deviation from the Landau-Lifshitz-Gilbert equation in the inertial regime of the magnetization, J. Appl. Phys., 117, 21, (2015); Mondal R., Berritta M., Nandy A.K., Oppeneer P.M., Relativistic theory of magnetic inertia in ultrafast spin dynamics, Phys. Rev. B, 96, (2017); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, 153, pp. 101-114, (1935); Gilbert T.L., (1956); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Bottcher D., Henk J., Significance of nutation in magnetization dynamics of nanostructures, Phys. Rev. B, 86, (2012); Ciornei M.-C., Rub J.M., Wegrowe J.-E., Magnetization dynamics in the inertial regime: Nutation predicted at short time scales, Phys. Rev. B, 83, (2011); Bhattacharjee S., Nordstrom L., Fransson J., Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett., 108, (2012); Kambersky V., On the Landau-Lifshitz relaxation in ferromagnetic metals, Can. J. Phys., 48, (1970); Kambersky V., On ferromagnetic resonance damping in metals, Czech. J. Phys. B, 26, 12, pp. 1366-1383, (1976); Kambersky V., Spin-orbital Gilbert damping in common magnetic metals, Phys. Rev. B, 76, (2007); Brataas A., Tserkovnyak Y., Bauer G.E.W., Scattering theory of Gilbert damping, Phys. Rev. Lett., 101, (2008); Ebert H., Mankovsky S., Kodderitzsch D., Kelly P.J., Ab Initio calculation of the Gilbert damping parameter via the linear response formalism, Phys. Rev. Lett., 107, (2011); Mondal R., Berritta M., Oppeneer P.M., Relativistic theory of spin relaxation mechanisms in the Landau-Lifshitz-Gilbert equation of spin dynamics, Phys. Rev. B, 94, (2016); Mondal R., Berritta M., Oppeneer P.M., Generalisation of Gilbert damping and magnetic inertia parameter as a series of higher-order relativistic terms, J. Phys.: Condens. Matter, 30, 26, (2018); Fahnle M., Illg C., Electron theory of fast and ultrafast dissipative magnetization dynamics, J. Phys.: Condens. Matter, 23, 49, (2011); Fahnle M., Steiauf D., Illg C., Generalized Gilbert equation including inertial damping: Derivation from an extended breathing Fermi surface model, Phys. Rev. B, 84, (2011); Mondal R., Relativisitic Theory of Laser-induced Magnetization Dynamics, (2017); Strange P., [Relativistic Quantum Mechanics: With Applications in Condensed Matter and Atomic Physics], (1998); Foldy L.L., Wouthuysen S.A., On the Dirac theory of spin 1/2 particles and its non-relativistic limit, Phys. Rev., 78, pp. 29-36, (1950); Eriksen E., Foldy-Wouthuysen transformation. Exact solution with generalization to the two-particle problem, Phys. Rev., 111, pp. 1011-1016, (1958); Silenko A.J., Foldy-Wouthuysen transformation for relativistic particles in external fields, J. Math. Phys., 44, 7, pp. 2952-2966, (2003); Silenko A.J., General properties of the Foldy-Wouthuysen transformation and applicability of the corrected original Foldy-Wouthuysen method, Phys. Rev. A, 93, (2016); De Vries E., Jonker J., Non-relativistic approximations of the Dirac Hamitonian, Nucl. Phys. B, 6, 3, pp. 213-225, (1968); Mondal R., Berritta M., Paillard C., Singh S., Dkhil B., Oppeneer P.M., Bellaiche L., Relativistic interaction Hamiltonian coupling the angular momentum of light and the electron spin, Phys. Rev. B, 92, (2015); Paillard C., Mondal R., Berritta M., Dkhil B., Singh S., Oppeneer P.M., Bellaiche L., New relativistic Hamiltonian: The angular magnetoelectric coupling, Proc. SPIE, 9931, (2016); Mondal R., Berritta M., Oppeneer P.M., Signatures of relativistic spin-light coupling in magnetooptical pump-probe experiments, J. Phys.: Condens. Matter, 29, 19, (2017); Berritta M., Mondal R., Carva K., Oppeneer P.M., Ab Initio theory of coherent laser-induced magnetization in metals, Phys. Rev. Lett., 117, (2016); Mondal R., Berritta M., Carva K., Oppeneer P.M., Ab initio investigation of light-induced relativistic spin-IP effects in magneto-optics, Phys. Rev. B, 91, (2015); Nowak U., Classical spin models, [Handbook of Magnetism and Advanced Magnetic Materials], 2, (2007); John R., Berritta M., Hinzke D., Muller C., Santos T., Ulrichs H., Nieves P., Walowski J., Mondal R., Chubykalo-Fesenko O., McCord J., Oppeneer P.M., Nowak U., Munzenberg M., Magnetisation switching of FePt nanoparticle recording medium by femtosecond laser pulses, Sci. Rep., 7, 1, (2017); Hinschberger Y., Hervieux P.-A., Foldy-Wouthuysen transformation applied to the interaction of an electron with ultrafast electromagnetic fields, Phys. Lett. A, 376, 67, pp. 813-819, (2012)","","Wegrowe J.-E.; Drouhin H.-J.; Razeghi M.; Jaffres H.","SPIE","The Society of Photo-Optical Instrumentation Engineers (SPIE)","Spintronics XI","19 August 2018 through 23 August 2018","San Diego","140486","0277786X","978-151062035-3","PSISD","","English","Proc SPIE Int Soc Opt Eng","Conference paper","Final","","Scopus","2-s2.0-85055568846" +"Wegrowe J.-E.; Olive E.","Wegrowe, J.-E. (7004315688); Olive, E. (6602922371)","7004315688; 6602922371","The magnetic monopole and the separation between fast and slow magnetic degrees of freedom","2016","Journal of Physics Condensed Matter","28","10","106001","","","","17","10.1088/0953-8984/28/10/106001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84960329748&doi=10.1088%2f0953-8984%2f28%2f10%2f106001&partnerID=40&md5=487b713ee1f200575b516aa545aaa280","LSI, Ecole Polytechnique, CEA, CNRS, Université Paris-Saclay, Palaiseau Cedex, 91128, France; GREMAN, UMR 7347, Université François Rabelais, CNRS, Parc de Grandmont, Tours, 37200, France","Wegrowe J.-E., LSI, Ecole Polytechnique, CEA, CNRS, Université Paris-Saclay, Palaiseau Cedex, 91128, France; Olive E., GREMAN, UMR 7347, Université François Rabelais, CNRS, Parc de Grandmont, Tours, 37200, France","The Landau-Lifshitz-Gilbert (LLG) equation that describes the dynamics of a macroscopic magnetic moment finds its limit of validity at very short times. The reason for this limit is well understood in terms of separation of the characteristic time scales between slow degrees of freedom (the magnetization) and fast degrees of freedom. The fast degrees of freedom are introduced as the variation of the angular momentum responsible for the inertia. In order to study the effect of the fast degrees of freedom on the precession, we calculate the geometric phase of the magnetization (i.e. the Hannay angle) and the corresponding magnetic monopole. In the case of the pure precession (the slow manifold), a simple expression of the magnetic monopole is given as a function of the slowness parameter, i.e. as a function of the ratio of the slow over the fast characteristic times. © 2016 IOP Publishing Ltd.","geometrical angle; inertial regime of the magnetization; magnetic monopole; magnetization dynamics","Magnetic moments; Magnetism; Magnetization; Mechanics; Characteristic time; Geometrical angle; Inertial regimes; Landau-Lifshitz-Gilbert equations; Magnetic monopoles; Magnetization dynamics; Simple expression; Slowness parameters; Degrees of freedom (mechanics)","","","","","","","Berry M.V., Quantal phase factors accompanying adiabatic changes, Proc. R. Soc., 392, (1984); Aharonov Y., Stern A., Origin of the geometrical forces accompanying Berry's geometrical potentials, Phys. Rev. Lett., 69, (1992); Hannay J.H., Angle variable holonomy in adiabatic excusion of an integrable Hamiltonian, J. Phys. A : Math. Gen., 18, 2, (1985); Berry M.V., Classical adiabatic angles and quantal adiabatic phase, J. Phys. A : Math. Gen., 18, 1, (1985); Bruno P., Blugel S., Et al., Berry phase effects in magnetism, Magnetisme Goes Nano, (2005); Berry M.V., Shukla P., Classical dynamics with curl forces, and motion driven by time-dependent flux, J. Phys. A : Math. Theor., 45, (2012); Sonin E.B., Spin currents and spin superfluidity, Adv. Phys., 59, pp. 181-255, (2010); Nagaosa N., Sinova J., Onoda S., MacDonald A.H., Ong N.P., Anomalous hall effect, Rev. Mod. Phys., 82, (2010); Xiao D., Chang M.-C., Niu Q., Berry phase effects on electronic properties, Rev. Mod. Phys., 82, (2010); Nagaosa N., Yu X.Z., Tokura Y., Gauge fields in real and momentum spaces in magnets: Monopoles and skyrmions, Phil. Trans. R. Soc., 370, (2012); Nagasawa F., Frustaglia D., Saarikoski H., Richter K., Nitta J., Control of the spin geometric phase in semiconductor quantum rings, Nat. Commun., 4, (2013); Bruno P., Nonquantized Dirac monopoles and strings in the berry phase of anisotropic spin systems, Phys. Rev. Lett., 93, (2004); Shibata J., Tatara G., Kohno H., Effect of spin current on uniform ferromagnetism : Domain nucleation, Phys. Rev. Lett., 94, (2005); Barnes S.E., Maekawa S., Current-spin coupling for ferromagnetic domain walls in fine wires, Phys. Rev. Lett., 95, (2005); Kurebayashi H., Et al., An antidamping spin-orbit torque originating from the Berry curvature, Nat. Nanotechnol., 9, (2014); Aharonov Y., Casher A., Topological quantum effects for neutral particles, Phys. Rev. Lett., 53, (1984); Aharonov Y., Pearle P., Vaidman L., Comment on proposed Aharonov-Casher effect: Another example of an Aharonov-Bohm effect from classical lag, Phys. Rev., 37, (1988); Hertel R., Wulfhekel W., Kirschner J., Domain-wall induced phase shifts in spin waves, Phys. Rev. Lett., 93, (2004); Hertel R., Curvature-induced magnetochirality, SPIN, 3, (2013); Kovalev A.A., Tserkovnyak Y., Thermomagnonic spin transfer and Peltier effects in insulating magnets, Europhys. Lett., 97, 6, (2012); Onose Y., Ideue T., Katsura H., Shiomi Y., Nagaosa N., Tokura Y., Obsevration of the Magnon Hall effect, Science, 329, (2010); Matsumoto R., Murakami S., Rotational motion of magnons and the thermal Hall effect, Phys. Rev., 84, (2011); Landau L.D., Lifshitz L.M., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.H., PhD Dissertation, (1956); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Mag., 40, (2004); Bar'Yakhtar V.G., Ivanov B.A., The Landau-Lifshitz equation: 80 years of history, advances, and prospects, Low Temp. Phys., 41, (2015); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Lakshmanan M., The fascinating world of the Landau-Lifshitz-Gilbert equation: An overview, Phil. Trans. R. Soc., 369, pp. 1280-1300, (2011); Pylypovskyi O.V., Kravchuk V.P., Sheka D.D., Makarov D., Schmidt O.G., Gaididei Y., Coupling of chiralities in spin and physical spaces: The Möbius ring as a case study, Phys. Rev. Lett., 114, (2015); Goussev A., Robbins J.M., Slastikov V., Domain wall motion in thin ferromagnetic nanotubes: Analytic results, Europhys. Lett., 105, 6, (2014); Stohr J., Siegmann H.C., Magnetism, from Fundamentals to Nanoscale Dynamics, (2006); Goussev A., Lund R.G., Robbins J.M., Slastikov V.O., Sonnenberg domain wall motion in magnetic nanowires: An asymptotic approach, Proc. R. Soc., 469, pp. 2160-2178, (2013); Miltat J., Alburquerque G., Thiaville A., An introduction to micromagnetics in the dynamics regime, Spin Dynamics in Confined Magnetic Structures i, 83, (2002); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, pp. 1677-1686, (1963); Coffey W.T., Kalmykov Y.P., The Langevin Equation, 27, (2012); Aron C., Barci D.G., Cugliandolo L.F., Arenas Z.G., Lozano G.S., Magnetization dynamics: Path-integral formalism for stochastic Landau-Lifshitz-Gilbert equation, J. Stat. Mech., 2014, 9, (2014); Skrotskii G.V., The Landau-Lifshitz equation revisited, Usp. Fiz. Nauk., 144, pp. 681-686, (1984); Maamache M., Exact solution and geometric angle for the classical spin system, Phys. Scr., 54, 1, pp. 21-23, (1996); Wegrowe J.-E., Ciornei M.-C., Magnetization dynamics, gyromagnetic relation, and inertial effects, Am. J. Phys., 80, (2012); Ciornei M.-C., Rubi J.M., Wegrowe J.-E., Magnetization dynamics in the inertial regime: Nutation predicted at short time scales, Phys. Rev., 83, (2011); Faehnle M., Steiauf D., Illg C., Generalized Gilbert equation including inertial damping : Cerivation from an extended breathing Fermi surface model, Phys. Rev., 84, (2011); Olive E., Lansac Y., Wegrowe J.-E., Beyond ferromagnetic resonance: The inertial regime of the magnetization, Appl. Phys. Lett., 100, (2012); Bhattacharjee S., Nordstrom L., Fransson J., Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett., 108, (2012); Olive E., Lansac Y., Meyer M., Hayoun M., Wegrowe J.-E., Deviation from Landau-Lifshitz-Gilbert equation in the inertial regime of the magnetization, J. Appl. Phys., 117, (2015); Thonig D., Hnek J., Eriksson O., Gilbert-like damping caused by time retardation in atomistic magnetization dynamics, Phys. Rev., 92, (2015); Li Y., Barras A.-L., Auffret S., Ebels U., Bailey W.E., Inertial terms to magnetization dynamics in ferromagnetic thin films, Phys. Rev., 92, (2015); Aharonov Y., Ben-Reuven E., Popescu S., Rohrlich D., Born-Oppenheimer revisited, Nucl. Phys., 350, (1991); Robbins J.M., Trigg G., Topological Phase Effects, pp. 549-584, (1997); Van Kampen N.G., Elimination of fast variables, Phys. Rep., 124, pp. 69-160, (1985); Berry M.V., Shukla P., High-order classical adiabatic reaction forces: Slow manifold for a spin model, J. Phys. A: Math. Theor., 43, (2010); Berry M.V., Shukla P., Slow manifold and Hannay angle in the spinning top, Eur. J. Phys., 32, 1, pp. 115-127, (2011); Griffiths D.J., Hnizdo V., Mansuripur's paradox, Am. J. Phys., 81, (2013); Landau L.D., Lifshitz E.M., Classical Theory of Fields, (1987); McDonlad K.T., Radiation by A Time-dependent Current Loop, (2010); Griffiths D.J., Dipoles at rest, Am. J. Phys., 60, (1992); Griffiths D.J., Dynamic dipoles, Am. J. Phys., 79, (2011); Holstein B.E., The adiabatic theorem and Berry's phase, Am. J. Phys., 57, (1989); Garg A., Berry phase near degeneracies : Beyond the simplest case, Am. J. Phys., 78, (2010)","","","Institute of Physics Publishing","","","","","","09538984","","JCOME","","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84960329748" +"Gholipour A.; Rajaei R.","Gholipour, Alireza (56414562900); Rajaei, Ramin (34768978000)","56414562900; 34768978000","The behavior analysis of magnetoresistive tunnel junction devices in state space","2019","IEEE Transactions on Nanotechnology","18","","8784417","798","805","7","1","10.1109/TNANO.2019.2931313","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85070590635&doi=10.1109%2fTNANO.2019.2931313&partnerID=40&md5=5f646f64a46fa5d619fc22a24550ddd6","Department of Electrical Engineering, Shahid Beheshti University G. C., Tehran, 1983963113, Iran","Gholipour A., Department of Electrical Engineering, Shahid Beheshti University G. C., Tehran, 1983963113, Iran; Rajaei R., Department of Electrical Engineering, Shahid Beheshti University G. C., Tehran, 1983963113, Iran","The behavior of magnetoresistive tunnel junction (MTJ) devices in the electronic (digital) circuits is governed by several differential equations. The LLG equation determines the dynamic of the magnetic polarization vector which ultimately affects the (anti)parallel resistance of MTJs. This vector differential equation is decomposed into two scalar differential equations. In the proposed method, the differential equations are expressed in the state space and the corresponding well-developed theories are applied. In fact, the device is considered as a multi-input multi-output control system and the qualitative solutions are presented. The state diagram gives an insight into the device behavior. It can provide additional information about the device performance and can be considered as a complementary technique of other available analysis approaches. With this ability, the designer can engineer the MTJ devices for their optimum performance in the circuit. Using this theory, we also suggested a power and performance improving approach for the spin transfer torque MTJ-based logic circuits. To show the efficiencies offered by the proposed method, a STT-MRAM cell and an array are designed and it is shown that better specifications can be achieved in terms of switching time and power dissipation. The reliability issues are also investigated and we show that the proposed power/performance improvement approach can effectively consider the reliability concerns. © 2002-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) differential equation; magnetic random access memory (MRAM); Magnetic tunnel junction (MTJ); state space","Computer circuits; Differential equations; Digital devices; Magnetic recording; Magnetic storage; Magnetism; MIMO systems; MRAM devices; Random access storage; State space methods; Complementary techniques; Landau-Lifshitz-Gilbert; Magnetic random access memory; Magnetic tunnel junction; Magnetoresistive tunnel junctions; Multiinput multioutput control system; Scalar differential equations; Vector differential equations; Tunnel junctions","","","","","University of Shahid Beheshti G. C., (SAD/600/1295)","Manuscript received January 6, 2019; revised June 5, 2019; accepted July 19, 2019. Date of publication July 30, 2019; date of current version August 8, 2019. This work was supported by the University of Shahid Beheshti G. C. under Grant SAD/600/1295. The review of this paper was arranged by associate editor J. Lyding. (Corresponding author: Alireza Gholipour.) The authors are with the Department of Electrical Engineering, Shahid Beheshti University G. C., Tehran 1983963113, Iran (e-mail: a_gholipour@ sbu.ac.ir; r_rajaei@sbu.ac.ir). Digital Object Identifier 10.1109/TNANO.2019.2931313","Shiota Y., Induction of coherent magnetization switching in a few atomic layers of FeCo using voltage pulses, Nature Mater., 11, pp. 39-43, (2012); Rajaei R., Gholipour A., Low power, reliable, and nonvolatile MSRAM cell for facilitating power gating and nonvolatile dynamically reconfiguration, IEEE Trans. Nanotechnol., 17, 2, pp. 261-267, (2018); Zhang L., Et al., Addressing the thermal issues of STT-MRAM from compact modeling to design techniques, IEEE Trans. Nanotechnol., 17, 2, pp. 345-352, (2018); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, 62, 1, pp. 570-578, (2000); Kumar V.R., Kaushik B.K., Patnaik A., An accurate FDTD model for crosstalk analysis of CMOS-gate-driven coupled RLC interconnects, IEEE Trans. Electromagn. Compat., 56, 5, pp. 1185-1193, (2014); Hariya A., Et al., Circuit design techniques for reducing the effects of magnetic flux on GaN-HEMTs in 5-MHz 100-W high power-density LLC resonant DC-DC converters, IEEE Trans. Power Electron., 32, 8, pp. 5953-5963, (2017); Deng E., Wang Z., Klein J.-O., Prenat G., Dieny B., Zhao W., High-frequency low-power magnetic full-adder based on magnetic tunnel junction with spin-hall assistance, IEEE Trans. Magn., 51, 11, (2015); Panagopoulos G.D., Augustine C., Roy K., Physics-based SPICEcompatible compact model for simulating hybrid MTJ/CMOS circuits, IEEE Trans. Electron Devices, 60, 9, pp. 2808-2814, (2013); Kazemi M., Ipek E., Eby G.F., Adaptive compact magnetic tunnel junction model, IEEE Trans. Electron Devices, 61, 11, pp. 3883-3891, (2014); Atherton D.P., An Introduction to Nonlinearity in Control Systems, (2011); Farlow S.J., An Introduction to Differential Equations and Their Applications, (2006); Lebl J., Notes on Diffy Qs: Differential Equations for Engineers, (2017); Xuet N., Et al., Physics-based compact modeling framework for state-of-theart and emerging STT-MRAM technology, Proc. IEEE Int. Electron Devices Meeting, pp. 2851-2854, (2015); Wang Z., Et al., Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque, J. Phys. D, Appl. Phys., 48, 6, pp. 1-7, (2015); D'Aquino M., Serpico C., Coppola G., Mayergoyz I.D., Bertotti G., Midpoint numerical technique for stochastic landau-lifshitz-gilbert dynamics, J. Appl. Phys., 99, 8, (2006); Chen B.J., Cai K., Han G.C., Lim S.T., Tran M., A portable dynamic switching model for perpendicular magnetic tunnel junctions considering both thermal and process variations, IEEE Trans. Magn., 51, 11, (2015); Wang Y., Et al., Compact model of dielectric breakdown in spin-transfer torque magnetic tunnel junction, IEEE Trans. Electron Devices, 63, 4, pp. 1762-1767, (2016); Worledge D.C., Et al., Spin torque switching of perpendicular Ta CoFeB MgO-based magnetic tunnel junctions, Appl. Phys. Lett., 98, 2, (2011); Gradshteyn I.S., Ryzhik I.M., Table of Integrals, Series, and Products, (2007); Tomita H., Et al., High-speed spin-transfer switching in GMR nanopillars with perpendicular anisotropy, IEEE Trans. Magn., 47, 6, pp. 1599-1602, (2011); Pal S., Islam A., 9-T SRAM cell for reliable ultralow-power applications and solving multibit soft-error issue, IEEE Trans. Device Mater. Rel., 16, 2, pp. 172-182, (2016); Zhao W., Et al., Failure and reliability analysis of STT-MRAM, Microelectron. Rel., 52, 9-10, pp. 1848-1852, (2012); Amirany R.R., Fully nonvolatile and low power full-adder based on spin transfer torque magnetic tunnel junction with spin-hall effect assistance, IEEE Trans. Magn., 54, 12, (2016); Zhao H., Xue L., Chi P., Zhao J., Approximate image storage with multi-level cellSTT-MRAMmain memory, Proc. IEEE/ACMInt.Conf. Comput. Aided Des., pp. 268-275, (2017)","A. Gholipour; Department of Electrical Engineering, Shahid Beheshti University G. C., Tehran, 1983963113, Iran; email: a_gholipour@sbu.ac.ir","","Institute of Electrical and Electronics Engineers Inc.","","","","","","1536125X","","","","English","IEEE Trans. Nanotechnol.","Article","Final","","Scopus","2-s2.0-85070590635" +"Weberszpil J.; Helayël-Neto J.A.","Weberszpil, J. (6508003773); Helayël-Neto, J.A. (7003863269)","6508003773; 7003863269","Structural scale q-derivative and the LLG equation in a scenario with fractionality","2017","EPL","117","5","50006","","","","8","10.1209/0295-5075/117/50006","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85019475332&doi=10.1209%2f0295-5075%2f117%2f50006&partnerID=40&md5=ef13bacac0020052773ef248f052a8dd","Universidade Federal Rural Do Rio de Janeiro, UFRRJ-IM/DTL, Av. Governador Roberto Silveira s/n Nova Iguacu, Rio de Janeiro, 695014, Brazil; Centro Brasileiro de Pesquisas Fisicas-CBPF, Rua Dr Xavier Sigaud 150, Rio de Janeiro, 22290-180 RJ, Brazil","Weberszpil J., Universidade Federal Rural Do Rio de Janeiro, UFRRJ-IM/DTL, Av. Governador Roberto Silveira s/n Nova Iguacu, Rio de Janeiro, 695014, Brazil; Helayël-Neto J.A., Centro Brasileiro de Pesquisas Fisicas-CBPF, Rua Dr Xavier Sigaud 150, Rio de Janeiro, 22290-180 RJ, Brazil","In the present contribution, we study the Landau-Lifshitz-Gilbert equation with two versions of structural derivatives which were recently proposed: the scale q-derivative in the non-extensive statistical mechanics and the axiomatic metric derivative. The latter presents the Mittag-Leffler functions as eigenfunctions. The use of structural derivatives aims to take into account long-range forces, possible non-manifest or hidden interactions and the dimensionality of space. Having this purpose in mind, we build up an evolution operator and a deformed version of the LLG equation. Damping in the oscillations naturally shows up without an explicit Gilbert damping term. © EPLA, 2017.","","","","","","","FAPERJ Rio de Janeiro and CNPq-Brazil","The authors wish to express their gratitude to FAPERJ Rio de Janeiro and CNPq-Brazil for the partial financial support.","Weberszpil J., Lazo M.J., Helayel-Neto J.A., Physica A, 436, (2015); Weberszpil J., Helayel-Neto J.A., Physica A, 450, (2016); Tsallis C., J. Stat. Phys., 52, 1-2, (1988); Tsallis C., Braz. J. Phys., 39 A, 2, (2009); Tsallis C., Introduction to Nonextensive Statistical Mechanics - Approaching A Complex World, (2009); Balankin A.S., Elizarraraz B.E., Phys. Rev. e, 85, 5, (2012); Balankin A.S., Espinoza B., Phys. Rev. e, 85, 2, (2012); Balankin A., Bory-Reyes J., Shapiro M., Physica A, 444, (2015); Chen W., Liang Y., Hei X., Fract. Calc. Appl. Anal., 19, (2016); Chen W., (2016); Lakshmanan M., Philos. Trans. R. Soc. A, 369, 1939, (2011); Mondal R., Berritta M., Oppeneer P.M., Phys. Rev. B, 94, 14, (2016); Ferona A.M., Camley R.E., Phys. Rev. B, 95, 10, (2017); Crowley P.J.D., Green A.G., Phys. Rev. A, 94, 6, (2016); Zhao Y., Et al., Sci. Rep., 6, 1, (2016); Kudo K., Phys. Rev. e, 94, 6, (2016); Gilbert T.L., IEEE Trans. Mag., 40, 6, (2004); Salazar M., Perez Alcazar G.A., Physica A, 424, (2015); Nobre F.D., Rego-Monteiro M.A., Tsallis C., Phys. Rev. Lett., 106, 14, (2011); Weberszpil J., Helayel-Neto J.A., J. Adv. Phys., 7, (2015); Weberszpil J., Helayel-Neto J.A., J. Adv. Phys., 13, (2017); Weberszpil J., Helayel-Neto J.A., Adv. High Energy Phys., 2014, (2014); Weberszpil J., Godinho C.F.L., Cherman A., Helayel-Neto J.A., PoS(ICMP 2012), (2012); Weberszpil J., Sotolongo-Costa O., J. Adv. Phys., 13, (2017); Magin R., Feng X., Baleanu D., Concepts in Mag. Resonance Part A, 34, 1, (2009); Bhalekar S., Daftardar-Gejji V., Baleanu D., Magin R., Comput. Math. Appl., 61, 5, (2011)","","","Institute of Physics Publishing","","","","","","02955075","","","","English","EPL","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85019475332" +"Wysin G.M.","Wysin, G.M. (6701324945)","6701324945","Magnetic vortex dynamics in the non-circular potential of a thin elliptic ferromagnetic nanodisk with applied fields","2017","AIMS Materials Science","4","2","","421","438","17","0","10.3934/matersci.2017.2.421","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85037110337&doi=10.3934%2fmatersci.2017.2.421&partnerID=40&md5=bf595115fe20991298eb62138be321da","Department of Physics, Kansas State University, Manhattan, 66506, KS, United States","Wysin G.M., Department of Physics, Kansas State University, Manhattan, 66506, KS, United States","Spontaneous vortex motion in thin ferromagnetic nanodisks of elliptical shape is dominated by a natural gyrotropic orbital part, whose resonance frequency ωG = k/G depends on a force constant and gyrovector charge, both of which change with the disk size and shape and applied in-plane or out-of-plane fields. The system is analyzed via a dynamic Thiele equation and also using numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equations for thin systems, including temperature via stochastic fields in a Langevin equation for the spin dynamics. A vortex is found to move in an elliptical potential with two principal axis force constants kx and ky, whose ratio determines the eccentricity of the vortex motion, and whose geometric mean kk = √ kxky determines the frequency. The force constants can be estimated from the energy of quasi-static vortex configurations or from an analysis of the gyrotropic orbits. kx and ky get modified either by an applied field perpendicular to the plane or by an in-plane applied field that changes the vortex equilibrium location. Notably, an out-ofplane field also changes the vortex gyrovector G, which directly influences ωG. The vortex position and velocity distributions in thermal equilibrium are found to be Boltzmann distributions in appropriate coordinates, characterized by the force constants.","Effective potential; Force constants; Gyrovector; LLG equation; Magnetic vortex; Stochastic dynamics; Thiele equation","","","","","","","","Schneider M., Hoffmann H., Zweck J., Lorentz microscopy of circular ferromagnetic permalloy nondisks, Appl Phys Lett, 77, (2000); Wysin G.M., Figueiredo W., Thermal vortex dynamics in thin circular ferromagnetic nanodisks, Phys Rev B, 86, (2012); Guslienko K.Y., Han X.F., Keavney D.J., Et al., Magnetic vortex core dynamics in cylindrical ferromagnetic dots, Phys Rev Lett, 96, (2006); Buchanan K.S., Roy P.E., Fradkin F.Y., Et al., Vortex dynamics in patterned ferromagnetic ellipses, J Appl Phys, 99, (2006); Wysin G.M., Vortex dynamics in thin elliptic ferromagnetic nanodisks, Low Temp Phys (Fiz Nizk Temp), 41, pp. 788-800, (2015); Kireev V.E., Ivanov B.A., Inhomogeneous states in a small magnetic disk with single-ion surface anisotropy, Phys Rev B, 68, (2003); Buchanan K.S., Roy P.E., Grimsditch M., Et al., Magnetic-field tunability of the vortex translational mode in micron-sized permalloy ellipses: Experiment and micromagnetic modeling, Phys Rev B, 74, (2006); de Loubens G., Riegler A., Pigeau B., Et al., Bistability of vortex core dynamics in a single perpendicularly magnetized nanodisk, Phys Rev Lett, 102, (2009); Fried J.P., Fangohr H., Kostylev M., Et al., Exchange-mediated, nonlinear, out-of-plane magnetic field dependence of the ferromagnetic vortex gyrotropic mode frequency driven by core deformation, Phys Rev B, 94, (2016); Thiele A.A., Applications of the gyrocoupling vector and dissipation dyadic in the dynamics of magnetic domains, J Appl Phys, 45, (1974); Garcia-Palacios J.L., Lazaro F.J., Langevin-dynamics study of the dynamical properties of small magnetic particles, Phys Rev B, 58, (1998); Wysin G.M., Vortex-in-nanodot potentials in thin circular magnetic dots, J Phys-Condens Mat, 22, (2010); Machado T.S., Rappoport T.G., Sampaio L.C., Vortex core magnetization dynamics induced by thermal excitation, Appl Phys Lett, 100, (2012)","G.M. Wysin; Department of Physics, Kansas State University, Manhattan, 66506, United States; email: wysin@phys.ksu.edu","","AIMS Press","","","","","","23720484","","","","English","AIMS Mat. Sc.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85037110337" +"Li J.; Yang Q.; Wang S.; Li Y.","Li, J. (55273220100); Yang, Q. (7404076426); Wang, S. (14021871000); Li, Y. (56162279800)","55273220100; 7404076426; 14021871000; 56162279800","Losses modeling based on domain wall processes and validation considering rotational excitation of electrical steel sheets","2018","2018 IEEE International Magnetic Conference, INTERMAG 2018","","","8508559","","","","0","10.1109/INTMAG.2018.8508559","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85066815484&doi=10.1109%2fINTMAG.2018.8508559&partnerID=40&md5=e138fc3fae6fc16c800505372cb79266","State Key Laboratory of Control and Simulation of Power System andGeneration Equipments, Tsinghua University, Beijing, China; State Key Laboratory ofReliability and Intelligence of Electrical Equipment, Hebei University ofTechnology, Tianjin, China; Municipal Key Laboratory of Advanced Technology of Electrical Engineering andEnergy, Tianjin Polytechnic University, Tianjin, China","Li J., State Key Laboratory of Control and Simulation of Power System andGeneration Equipments, Tsinghua University, Beijing, China; Yang Q., State Key Laboratory ofReliability and Intelligence of Electrical Equipment, Hebei University ofTechnology, Tianjin, China, Municipal Key Laboratory of Advanced Technology of Electrical Engineering andEnergy, Tianjin Polytechnic University, Tianjin, China; Wang S., State Key Laboratory of Control and Simulation of Power System andGeneration Equipments, Tsinghua University, Beijing, China; Li Y., State Key Laboratory ofReliability and Intelligence of Electrical Equipment, Hebei University ofTechnology, Tianjin, China","On the basis of damping principle of vibration, the domain wall processes is investigated and modeled at low-to-medium frequencies in electrical steel sheets. Due to the energy dissipation chiefly descends from a micro-vortex current caused by domain wall motion, the coupled Landau-Lifshitz-Gilbert (LLG) and Maxwell electromagnetic diffusion equations are thus considered to describe the high-frequency characteristics. The overall core losses are eventually deduced in terms of separate contributions by domain wall processes and classical eddy current. Moreover, the calculation model can be extended to rotational excitation pattern. Hence, taking the typical electrical steel sheets as example, the novel core losses calculation model is analysed and compared with the total alternating core losses supplied by electrical steel sheets manufacturers and the 3-D rotating experimental core losses of sheets specimens which are carried out by using a 3-D magnetic properties testing system, and also achieve some beneficial conclusions. 1. Since the domain wall processes is essentially the magnetic moment rotation, then domain wall motion can be interpreted by solving LLG equation, that is [1], [2]:\begin{align*} \partial J/ \partial t \quad =- xJ \times [H_{eff}+(\alpha /J_{s}) J\times H_{eff}], (1)\\ \vert J \vert = \quad J_{s}(1) \end{align*}where, $J \quad = \mu _{0}M$ represents the magnetic polarization vector inside the domain, $M$ is the magnetization vector, $\mu _{0}$ is the permeability of vacuum, $ \chi =|e| / m_{e} \quad = 1.76 \times 10 ^{11} \mathrm {T}{-1} \mathrm {s}^{-1}$ is the absolute value of the electron gyromagnetic ratio [3]; $H_{eff}$ represents the overall effective field, which affects on the magnetic moments; $\alpha = \eta J_{s}$ is the qualitative dimensionless damping constant (Landau-Lifshitz damping coefficient), $eta$ is the damping coefficient of domain wall motion, $J_{s}$ is the saturation polarization. The first term on the right side of Eq. (1) describes the magnetic moment precession around the effective field direction, while the second term is the damping motion towards the effective field. 2. As regard to the right sheet with the walls in Fig. 1, in effect of the high-frequency excitation field $H$, the wall moves to make on both sides of the domains contraction and expansion. Now, by applying Maxwell electromagnetic diffusion equation:\begin{equation*} \partial {2}H_{vor}/ \partial y{2} \quad =\sigma \mu _{0}[ \partial (M+H_{vor}+H)/\partial t](2)\end{equation*}where, $\sigma $ is the electrical conductivity of magnetic materials and the vortex current field $H_{vor}$ is directed to $y -$axis. At this point, such a response can be described in general terms by the solution of the coupled LLG (Eq. (1)) and Maxwell electromagnetic diffusion (Eq. (2)) equations. 3. According to the above derivation, the overall core losses per unit mass of electrical steel sheets are eventually deduced in terms of separate contributions by classical eddy current and domain wall processes, as follows:\begin{equation} P_{cl} \quad = P_{cel}+P_{mel}{-} \quad = \left({ \sigma \pi {2}d{2}/ 3 \rho }\right) f{2}(B_{m}){2}+\left({\sigma \pi {2}d{2}/ 4 \rho }\right) f{2}(B- \mathrm {m}) {2}=\left({ 7 \sigma \pi {2}d{2}/ 12 \rho }\right) f{2}(B_{m}){2}[\mathrm {W} /kg](3)\end{equation}where, $P_{cl}$ is the overall core losses per unit mass of electrical steel sheets; $P_{cel}$ is the classical eddy current loss per unit mass; $P_{mel}{-}$ is the mean micro-vortex current losses per unit mass; $d$ is the thickness of the magnetic sheet; $ \rho$ is the mass density of magnetic materials; $f$ is the excitation frequency; $B_{m}$ is the peak flux density. 4. In order to validate the precision of the calculation model, the total alternating core losses supplied by electrical steel sheets manufacturers are used to compare with the calculation of Eq. (3), including cold-rolled GO electrical steel, NO electrical steel and hot-rolled electrical steel over wide range of excitation frequency [4], [5]. In addition, the model can be extended to rotational excitation pattern, so the 3-D rotational experimental core losses of typical electrical steel sheets carried out by using a 3-D magnetic properties testing system are also considered in the validity of the calculation model [6], [7]. The typical comparison result is shown in Fig. 2. © 2018 IEEE","","Cold rolled steel; Cold rolling; Damping; Diffusion; Domain walls; Eddy current testing; Energy dissipation; Hot rolled steel; Hot rolling; Magnetic cores; Magnetic domains; Magnetic moments; Magnetic properties; Maxwell equations; Metal cladding; Polarization; Saturation magnetization; Silicon steel; Steel testing; Vortex flow; Contraction and expansion; Electrical conductivity; Electrical steel sheets; High frequency characteristics; High-frequency excitation; Landau-Lifshitz-Gilbert; Magnetic polarizations; Saturation polarization; Steel sheet","","","","","","","Landau L.D., Lifshitz E.M., 8 ofCourse ofTheoreticalPhysics: Electrodynamics of Continuous Media[M], (1984); Gilbert T.L., A lagrangian formulation of gyro-magnetic equation ofthe magnetization field[J], Phys. Rev., 100, (1955); Bottauscio O., Fiorillo F., Beatrice C., Et al., Modeling high-frequency magnetic losses in transverse anisotropy amorphous ribbons[J], IEEE Trans. Magn., 51, 3, (2015); WUSTEEL Cold-Rolled GO Electrical Steel, (2010); BAOSTEEL Cold-Rolled NO Electrical Steel; Li Y.J., Yang Q.X., Zhu J.G., Et al., Design and analysis of a novel 3-D magnetization structure for laminated silicon steel[J], IEEE Trans. Magn., 50, 2, (2014); Li J.S., Yang Q.X., Li Y.J., Et al., Anomalous loss modeling and validation of magnetic materials in electrical engineerings, IEEE Trans. Appl. Supercon, 26, 4, (2016)","","","Institute of Electrical and Electronics Engineers Inc.","","2018 IEEE International Magnetic Conference, INTERMAG 2018","23 April 2018 through 27 April 2018","Singapore","141475","","978-153866425-4","","","English","IEEE Int. Magn. Conf., INTERMAG","Conference paper","Final","","Scopus","2-s2.0-85066815484" +"Ayouch C.; Essoufi E.-H.; Tilioua M.","Ayouch, C. (57189905298); Essoufi, E.-H. (6504162169); Tilioua, M. (6507877823)","57189905298; 6504162169; 6507877823","On a non-scalar damping model in micromagnetism","2018","International Journal of Dynamical Systems and Differential Equations","8","1-2","","6","18","12","2","10.1504/IJDSDE.2018.10009155","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85040458074&doi=10.1504%2fIJDSDE.2018.10009155&partnerID=40&md5=ac5e68e5ccaca373602dda67a41cb9f6","Laboratoire MISI, FST Settat, University Hassan I, Settat, 26000, Morocco; M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","Ayouch C., Laboratoire MISI, FST Settat, University Hassan I, Settat, 26000, Morocco; Essoufi E.-H., Laboratoire MISI, FST Settat, University Hassan I, Settat, 26000, Morocco; Tilioua M., M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","We consider a mathematical model describing magnetisation dynamics with non-scalar damping. The model consists on a generalised Landau-Lifshitz-Gilbert equation with a general damping tensor. We apply Faedo-Galerkin/penalty method to show the existence of global weak solutions in one-dimensional case. Copyright © 2018 Inderscience Enterprises Ltd.","Faedo-Galerkin method; Ferromagnetic materials; Global existence; LLG equation","Ferromagnetic materials; Galerkin methods; Damping model; Global existence; Global weak solution; Landau-Lifshitz-Gilbert equations; LLG equation; Micro magnetisms; Damping","","","","","Providence Health Care, PHC, (MA/14/301); Ministry of Higher Education and Scientific Research, MHESR; Ministère des Affaires Étrangères; Ministère des Affaires Sociales et de la Santé","The research is supported by the PHC Volubilis program MA/14/301 “Elaboration et analyse de modèles asymptotiques en micro-magnétisme, magnéto-élasticité et électro-élasticité” with joint financial support from the French Ministry of Foreign Affairs and the Moroccan Ministry of Higher Education and Scientific Research.","Alouges F., Soyeur A., On global weak solutions for landau–Lifshitz equations: Existence and non uniqueness, Nonlinear Analysis, 18, pp. 1071-1084, (1992); Bartels S., Prohl A., Convergence of an implicit finite element method for the landau–Lifshitz–Gilbert equation, SIAM Journal on Numerical Analysis, 44, pp. 1405-1419, (2006); Baryakthar V.G., Ivanov B.A., Sukstanskii A.L., Melikhov E.Yu., Soliton relaxation in magnets, Physical Review B, 56, pp. 619-635; Bertsch M., Podio-Guidugli P., Valente V., On the dynamics of deformable ferromagnets. i. Global weak solutions for soft ferromagnets at rest, Annali Di Matematica Pura Ed Applicata, 179, 4, pp. 331-360; Carbou G., Fabrie P., Time average in micromagnetism, The Journal of Differential Equations, 147, pp. 383-409; Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Transactions on Magnetics, 40, (2004); Guo B., Hong M.C., The landau–Lifshitz equation of the ferromagetic spin chain and harmonic maps, Calculus of Variations and Partial Differential Equations, 1, pp. 311-334, (1993); Hadda M., Tilioua M., On magnetization dynamics with inertial effects, Journal of Engineering Mathematics, 88, pp. 197-206, (2014); Lions J.L., Quelques Méthodes De Résolution Des Problèmes Aux Limites Non Linéaires, (1969); Melcher C., Ptashnyk M., Landau-Lifshitz-slonczewski equations: Global weak and classical solutions, The SIAM Journal on Mathematical Analysis, 45, 1, pp. 407-429, (2013); Podio-Guidugli P., On dissipation mechanisms in micromagnetics, The European Physical Journal B, 19, pp. 417-424, (2001); Podio-Guidugli P., Valente V., Existence of global-in-time weak solutions to a modified gilbert equation, Nonlinear Analysis, 47, pp. 147-158, (2001); Prohl A., Computational micromagnetism, Advances in Numerical Mathematics, (2001); Rossi E., Heinonen O.G., MacDonald A.H., Dynamics of magnetization coupled to a thermal bath of elastic modes, Physical Review B, 72, (2005); Roubiek T., Tomassetti G., Zanini C., The gilbert equation with dry-friction type damping, Journal of Mathematical Analysis and Applications, 355, 2, pp. 453-468, (2009); Safonov V.L., Bertram H.N., Fluctuation-dissipation considerations and damping models for ferromagnetic materials, Journal of Applied Physics, 94, (2003); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Applied Numerical Mathematics, 46, 1, pp. 95-111, (2003); Slonczewski J., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, pp. L1-L7, (1996); Tilioua M., Current-induced magnetization dynamics. Global existence of weak solutions, Journal of Mathematical Analysis and Applications, 373, pp. 635-642, (2011); Visintin A., On the landau–Lifshitz equation for ferromagnetism, Japan Journal of Industrial and Applied Mathematics, 2, pp. 69-84, (1985); Weinan E., Wang X.-P., Numerical methods for the landau–Lifshitz equation, SIAM Journal on Numerical Analysis, 38, 5, pp. 1647-1665, (2000); Zhang S., Zhang S.S.-L., Generalization of the landau–Lifshitz–Gilbert equation for conducting ferromagnets, Physical Review Letters, 102, (2009)","M. Tilioua; M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, Boutalamine, Errachidia, P.O. Box 509, 52000, Morocco; email: m.tilioua@fste.umi.ac.ma","","Inderscience Publishers","","","","","","17523583","","","","English","Int. J. Dyn. Syst. Differ. Equ.","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85040458074" +"Yamaji T.; Imamura H.","Yamaji, Toshiki (7102897773); Imamura, Hiroshi (57386086300)","7102897773; 57386086300","Stability analysis of microwave-assisted magnetization reversal in exchange coupled nano magnets","2017","Journal of the Physical Society of Japan","86","6","065001","","","","0","10.7566/JPSJ.86.065001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85020699291&doi=10.7566%2fJPSJ.86.065001&partnerID=40&md5=34b1f2b0fe7084960bbfb2af46c4231b","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","Yamaji T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan; Imamura H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","The stability analysis was applied to the study of magnetization dynamics under action of microwave magnetic field in exchange coupled nano magnets. It was found that the stability criteria representing the magnetization reversal conditions at a microwave effective and non-effective regions are det A = 0 and det H = 0, respectively. Here, A is the stability matrix which is obtained from the linearized Landau–Lifshitz–Gilbert (LLG) equation, and H is the Hurwitz matrix. The result of the stability analysis was in good agreement with that of the LLG simulation. © 2017 The Physical Society of Japan.","","","","","","","","","Nozaki Y., Ohta M., Taharazako S., Tateishi K., Yoshimura S., Matsuyama K., Appl. Phys. Lett., 91, (2007); Zhu J.-G., Zhu X., Tang Y., IEEE Trans. Magn., 44, (2008); Okamoto S., Kikuchi N., Furuta M., Kitakami O., Shimatsu T., J. Phys. D, 48, (2015); Victora R., Shen X., IEEE Trans. Magn., 41, (2005); Richter H.J., Dobin A.Y., J. Appl. Phys., 99, (2006); Ghidini M., Asti G., Pellicelli R., Pernechele C., Solzi M., J. Magn. Magn. Mater., 316, (2007); Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, (2001); Bertotti G., Mayergoyz I.D., Serpico C., D'Aquino M., Bonin R., J. Appl. Phys., 105, (2009); Tanaka T., Kashiwagi S., Furomoto Y., Otsuka Y., Matsuyama K., Nanoscale Res. Lett., 8, (2013); Yamaji T., Imamura H., Appl. Phys. Lett., 109, (2016); Richter H.J., J. Phys. D, 40, (2007); Fukushima H., Nakatani Y., Hayashi N., IEEE Trans. Magn., 34, (1998); Parks P.C., Math. Proc. Cambridge Philos. Soc., 58, (1962)","","","Physical Society of Japan","","","","","","00319015","","JUPSA","","English","J. Phys. Soc. Jpn.","Article","Final","","Scopus","2-s2.0-85020699291" +"Senthil Kumar V.; Kavitha L.; Boopathy C.; Gopi D.","Senthil Kumar, V. (56288957900); Kavitha, L. (6507907076); Boopathy, C. (57193765286); Gopi, D. (59157674200)","56288957900; 6507907076; 57193765286; 59157674200","Loss-less propagation, elastic and inelastic interaction of electromagnetic soliton in an anisotropic ferromagnetic nanowire","2017","Communications in Nonlinear Science and Numerical Simulation","51","","","50","65","15","6","10.1016/j.cnsns.2017.03.020","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85016432448&doi=10.1016%2fj.cnsns.2017.03.020&partnerID=40&md5=dbe8f363d5b9b0843b1da2b98b8cfc5c","Department of Physics, Periyar University, Salem, 636 011, Tamilnadu, India; Department of Physics, School of Basic and Applied Sciences, Central University of Tamilnadu(CUTN), Thiruvarur, 610 101, Tamilnadu, India; The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy; Department of Chemistry, Periyar University, Salem, 636 011, Tamilnadu, India","Senthil Kumar V., Department of Physics, Periyar University, Salem, 636 011, Tamilnadu, India; Kavitha L., Department of Physics, School of Basic and Applied Sciences, Central University of Tamilnadu(CUTN), Thiruvarur, 610 101, Tamilnadu, India, The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy; Boopathy C., Department of Physics, Periyar University, Salem, 636 011, Tamilnadu, India; Gopi D., Department of Chemistry, Periyar University, Salem, 636 011, Tamilnadu, India","Nonlinear interaction of electromagnetic solitons leads to a plethora of interesting physical phenomena in the diverse area of science that include magneto-optics based data storage industry. We investigate the nonlinear magnetization dynamics of a one-dimensional anisotropic ferromagnetic nanowire. The famous Landau–Lifshitz–Gilbert equation (LLG) describes the magnetization dynamics of the ferromagnetic nanowire and the Maxwell's equations govern the propagation dynamics of electromagnetic wave passing through the axis of the nanowire. We perform a uniform expansion of magnetization and magnetic field along the direction of propagation of electromagnetic wave in the framework of reductive perturbation method. The excitation of magnetization of the nanowire is restricted to the normal plane at the lowest order of perturbation and goes out of plane for higher orders. The dynamics of the ferromagnetic nanowire is governed by the modified Korteweg-de Vries (mKdV) equation and the perturbed modified Korteweg-de Vries (pmKdV) equation for the lower and higher values of damping respectively. We invoke the Hirota bilinearization procedure to mKdV and pmKdV equation to construct the multi-soliton solutions, and explicitly analyze the nature of collision phenomena of the co-propagating EM solitons for the above mentioned lower and higher values of Gilbert-damping due to the precessional motion of the ferromagnetic spin. The EM solitons appearing in the higher damping regime exhibit elastic collision thus yielding the fascinating state restoration property, whereas those of lower damping regime exhibit inelastic collision yielding the solitons of suppressed intensity profiles. The propagation of EM soliton in the nanoscale magnetic wire has potential technological applications in optimizing the magnetic storage devices and magneto-electronics. © 2017 Elsevier B.V.","Electromagnetic soliton; Landau-Lifshitz-Gilbert equation; Magnetization dynamics; Reductive perturbation method","Anisotropy; Circular waveguides; Damping; Dynamics; Electromagnetic waves; Ferromagnetic materials; Ferromagnetism; Magnetic storage; Magnetoplasma; Maxwell equations; Nanomagnetics; Nanowires; Nonlinear equations; Perturbation techniques; Solitons; Elastic interactions; Electromagnetic solitons; Ferromagnetic nanowire; Inelastic interaction; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Modified korteweg-de vries equations; Nonlinear interactions; Physical phenomena; Reductive perturbation methods; Magnetization","","","","","","","Li J., Papadopoulos C., Xu J.M., Moskovits M., Appl Phys Lett, 75, (1999); Sun S., Murray C.B., Weller D., Folks L., Moser A., Science, 287, pp. 1989-1992, (2000); 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Verheest F., Hellberg M.A., Hereman W.A., Phys Rev E, 86, (2012); Kumar V.R., Radha R., Wadati M., Phys Rev A, 78, (2008); Kanna T., Lakshmanan M., Dinda P.T., Akhmediev N., Phys Rev E, 73, (2006); Liu B., He X.-D., Li S.-J., Phys Rev E, 84, (2011); Ablowitz M.J., Clarkson P.A., Solitons, nonlinear evolution equations and inverse scattering, (1991); Nimmo J.J.C., Phys Lett A, 99, (1983); Kraenkel R.A., Senthilvelan M., Zenchuk A.I., Phys Lett A, 273, pp. 183-193, (2000); Zhang H.-Q., Tian B., Meng X.-H., Xing L., Liu W.-J., Eur Phys J B, 72, (2009); Li Y., Ma W.-X., Zhang J.E., Phys Lett A, 275, (2000); Hirota R., The direct method in soliton theory, (2004); Wang D.-S., Zhang D.-J., Yang J., J Math Phys, 51, (2010); Sharping J.E., Fiorentino M., Kumar P., Windeler R.S., IEEE Photon Tech Lett, 14, (2002); Demircan A., Amiranashvili S., Steinmeyer G., Phys Rev Lett, 106, (2011)","L. Kavitha; Department of Physics, School of Basic and Applied Sciences, Central University of Tamilnadu(CUTN), Thiruvarur, 610 101, India; email: louiskavitha@yahoo.co.in","","Elsevier B.V.","","","","","","10075704","","","","English","Comm. Nonlinear Sci. Numer. Simul.","Article","Final","","Scopus","2-s2.0-85016432448" +"Tang H.-M.; Jia X.-T.; Wang S.-Z.","Tang, Hui-Min (57192814381); Jia, Xing-Tao (8633834900); Wang, Shi-Zhuo (56440521900)","57192814381; 8633834900; 56440521900","Thermal spin transfer torque in Fe|Ag|YIG multilayers","2017","Frontiers of Physics","12","3","128501","","","","1","10.1007/s11467-016-0649-3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85008230276&doi=10.1007%2fs11467-016-0649-3&partnerID=40&md5=0c2d155810b360c2158cab364de5d3ea","Department of Physics, Beijing Normal University, Beijing, 100875, China; School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo, 454000, China","Tang H.-M., Department of Physics, Beijing Normal University, Beijing, 100875, China; Jia X.-T., School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo, 454000, China; Wang S.-Z., Department of Physics, Beijing Normal University, Beijing, 100875, China","We investigated the thermal spin transfer effect in FM|NM|YIG multilayers using the first principles scattering theory. At room temperature, the spin Seebeck torque TSSE ~ 1:0 μJ/(K·m2) in an Ag|Fe|Ag|YIG multilayer, which is around 40% larger than that estimated from mixing conductance. The quantum effects such as interlayer exchange coupling between FM and YIG could be responsible for the enhancements. Based on the LLG equation, we predict that a temperature bias of ~ 10 K can reverse the magnetic configurations, circularly, in a multilayer at room temperature. © 2017, Higher Education Press and Springer-Verlag Berlin Heidelberg.","spin Seebeck torque; spin transfer torque; YIG","","","","","","","","Bauer G.E.W., Saitoh E., van Wees B.J., Spin caloritronics, Nat. Mater., 11, 5, (2012); Hatami M., Bauer G.E.W., Zhang Q., Kelly P.J., Thermal spin-transfer torque in magnetoelectronic devices, Phys. Rev. Lett., 99, 6, (2007); Yu H., Granville S., Yu D.P., Ansermet J.P., Evidence for thermal spin-transfer torque, Phys. Rev. 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Lett., 106, 21, (2011); Heinrich B., Burrowes C., Montoya E., Kardasz B., Girt E., Song Y.Y., Sun Y., Wu M.Z., Spin pumping at the magnetic insulator (YIG)/normal metal (Au) interfaces, Phys. Rev. Lett., 107, 6, (2011); Kurebayashi H., Dzyapko O., Demidov V.E., Fang D., Ferguson A.J., Demokritov S.O., Controlled enhancement of spin-current emission by three-magnon splitting, Nat. Mater., 10, 9, (2011); Padron-Hernandez E., Azevedo A., Rezende S.M., Amplification of spin waves by thermal spin-transfer torque, Phys. Rev. Lett., 107, 19, (2011); Castel V., Vlietstra N., Ben Youssef J., van Wees B.J., Platinum thickness dependence of the inverse spin-Hall voltage from spin pumping in a hybrid yttrium iron garnet/platinum system, Appl. Phys. Lett., 101, 13, (2012); Huang S.Y., Fan X., Qu D., Chen Y.P., Wang W.G., Wu J., Chen T.Y., Xiao J.Q., Chien C.L., Transport magnetic proximity effects in platinum, Phys. Rev. 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B, 84, 5, (2011); Tserkovnyak Y., Brataas A., Bauer G.E.W., Spin pumping and magnetization dynamics in metallic multilayers, Phys. Rev. B, 66, 22, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Enhanced Gilbert damping in thin ferromagnetic films, Phys. Rev. Lett., 88, 11, (2002); Gunnarsson O., Jepsen O., Andersen O.K., Selfconsistent impurity calculations in the atomic-spheres approximation, Phys. Rev. B, 27, 12, (1983); Andersen O.K., Jepsen O., Explicit, first-principles tight-binding theory, Phys. Rev. Lett., 53, 27, (1984); Jepsen O., Andersen O.K., Glotzel D., Highlights of Condensed Matter Theory, (1985); Wang S., Xu Y., Xia K., First-principles study of spin-transfer torques in layered systems with noncollinear magnetization, Phys. Rev. B, 77, 18, (2008); Jia X., Liu K., Xia K., Bauer G.E.W., Spin transfer torque on magnetic insulators, EPL, 96, 1, (2011); Hals K.M.D., Brataas A., Tserkovnyak Y., Scattering theory of charge-current induced magnetization dynamics, EPL, 90, 4, (2010); Bruno P., Chappert C., Oscillatory coupling between ferromagnetic layers separated by a nonmagnetic metal spacer, Phys. Rev. Lett., 67, 12, (1991)","X.-T. Jia; School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo, 454000, China; email: jiaxingtao@hpu.edu.cn","","Higher Education Press","","","","","","20950462","","","","English","Front. Phy.","Article","Final","","Scopus","2-s2.0-85008230276" +"Arbeláez-Echeverri O.D.; Agudelo-Giraldo J.D.; Restrepo-Parra E.","Arbeláez-Echeverri, O.D. (57189468498); Agudelo-Giraldo, J.D. (55947941600); Restrepo-Parra, E. (23986169100)","57189468498; 55947941600; 23986169100","Atomistic simulation of static magnetic properties of bit patterned media","2016","Physica E: Low-Dimensional Systems and Nanostructures","83","","","486","490","4","1","10.1016/j.physe.2015.12.016","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84971343337&doi=10.1016%2fj.physe.2015.12.016&partnerID=40&md5=b86063579b0666cfc41b9affee68ae28","Departamento de fisica y quimica, Universidad Nacional de Colombia – Sede Manizales, A.A. 127 Manizales, Colombia; PCM Computational Applications, Academic Research Group, Colombia","Arbeláez-Echeverri O.D., Departamento de fisica y quimica, Universidad Nacional de Colombia – Sede Manizales, A.A. 127 Manizales, Colombia, PCM Computational Applications, Academic Research Group, Colombia; Agudelo-Giraldo J.D., Departamento de fisica y quimica, Universidad Nacional de Colombia – Sede Manizales, A.A. 127 Manizales, Colombia, PCM Computational Applications, Academic Research Group, Colombia; Restrepo-Parra E., Departamento de fisica y quimica, Universidad Nacional de Colombia – Sede Manizales, A.A. 127 Manizales, Colombia, PCM Computational Applications, Academic Research Group, Colombia","In this work we present a new design of Co based bit pattern media with out-of-plane uni-axial anisotropy induced by interface effects. Our model features the inclusion of magnetic impurities in the non-magnetic matrix. After the material model was refined during three iterations using Monte Carlo simulations, further simulations were performed using an atomistic integrator of Landau–Lifshitz–Gilbert equation with Langevin dynamics to study the behavior of the system paying special attention to the super-paramagnetic limit. Our model system exhibits three magnetic phase transitions, one due to the magnetically doped matrix material and the weak magnetic interaction between the nano-structures in the system. The different magnetic phases of the system as well as the features of its phase diagram are explained. © 2016","Atomistic simulation; Bit patterned media; Bit patterned media; LLG equation","Impurities; Intelligent systems; Monte Carlo methods; Nanostructures; Phase diagrams; Atomistic simulations; Bit-patterned media; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic interactions; Magnetic phase transitions; Paramagnetic limits; Static magnetic properties; Magnetism","","","","","Universidad Nacional de Colombia, UNAL, (23046, 23088)","The authors gratefully acknowledge the financial support from the Direccion de Investigaciones of the Universidad Nacional de Colombia during the course of this research under the projects 23088 and 23046 . They also want to acknowledge R.F.L. Evans and other members of the Computational Magnetism Group of the University of York for the insightful conversations during the development of the model.","Albrecht T.R., Bedau D., Dobisz E., Gao H., Grobis M., Hellwig O., Kercher D., Lille J., Marinero E., Patel K., Ruiz R., Schabes M.E., Wan L., Weller D., Wu T.-W., Bit patterned media at 1 Tdot/in2 and beyond, IEEE Trans. Magn., 49, 2, pp. 773-778, (2013); Terris B., Fabrication challenges for patterned recording media, J. Magn. Magn. Mater., 321, 6, pp. 512-517, (2009); Yang J.K.W., Chen Y., Huang T., Duan H., Thiyagarajah N., Hui H.K., Leong S.H., Ng V., Fabrication and characterization of bit-patterned media beyond 1.5 Tbit/in2, Nanotechnology, 22, 38, (2011); Albrecht T.R., Arora H., Ayanoor-Vitikkate V., Beaujour J.-M., Bedau D., Berman D., Bogdanov A.L., Chapuis Y.-A., Cushen J., Dobisz E.E., Doerk G., Gao H., Grobis M., Gurney B., Hanson W., Hellwig O., Hi- rano T., Jubert P.-O., Kercher D., Lille J., Liu Z., Mate C.M., Obukhov Y., Patel K.C., Rubin K., Ruiz R., Schabes M., Wan L., Weller D., Wu T.-W., Yang E., Bit-patterned magnetic recording: theory, media fabrication, and recording performance, IEEE Trans. Magn., 51, 5, pp. 1-42, (2015); Thomson T., Hu G., Terris B., Intrinsic distribution of magnetic anisotropy in thin films probed by patterned nanostructures, Phys. Rev. Lett., 96, 25, (2006); Hellwig O., Berger A., Thomson T., Dobisz E., Bandic Z.Z., Yang H., Kercher D.S., Fullerton E.E., Separating dipolar broadening from the intrinsic switching field distribution in perpendicular patterned media, Appl. Phys. Lett., 90, 16, (2007); Kikitsu A., Prospects for bit patterned media for high-density magneticrecording, J. Magn. Magn. Mater., 321, 6, pp. 526-530, (2009); Richter H., Dobin A., Heinonen O., Gao K., Veerdonk R.V.D., Lynch R., Xue J., Weller D., Asselin P., Erden M., Brockie R., Recording on bit-patterned media at densities of 1 Tb/in2 and beyond, IEEE Trans. Magn., 42, 10, pp. 2255-2260, (2006); Richter H.J., Dobin A.Y., Lynch R.T., Weller D., Brockie R.M., Heinonen O., Gao K.Z., Xue J., Veerdonk R.J.M.V.D., Asselin P., Erden M.F., Recording potential of bit-patterned media, Appl. Phys. Lett., 88, 22, (2006); Duman T., Kurtas E., Erden M., Bit-patterned media with written-in errors: modeling, detection, and theoretical limits, IEEE Trans. Magn., 43, 8, pp. 3517-3524, (2007); Nabavi S., Vijaya Kumar B., Bain J., Two-dimensional pulse response and media noise modeling for bit-patterned media, IEEE Trans. Magn., 44, 11, pp. 3789-3792, (2008); Nabavi S., Vijaya Kumar B., Bain J., Hogg C., Majetich S., Application of Image processing to characterize patterning noise in self-assembled nano-masks for bit-patterned media, IEEE Trans. Magn., 45, 10, pp. 3523-3526, (2009); van de Veerdonk R., Weller D., Determination of switching field distributions for perpendicular recording media, IEEE Trans. Magn., 39, 1, pp. 590-593, (2003); Kalezhi J., Miles J., Belle B., Dependence of switching fields on island shape in bit patterned media, IEEE Trans. Magn., 45, 10, pp. 3531-3534, (2009); Lima F., Moreira J., Andrade J., Costa U., The ferromagnetic Ising model on a Voronoi–Delaunay lattice, Physica A: Stat. Mech. Appl., 283, 1-2, pp. 100-106, (2000); Lima F., Costa U., Costa Filho R., Critical behavior of the 3D Ising model on a Poissonian random lattice, Physica A: Stat. Mech. Appl., 387, 7, pp. 1545-1550, (2008); Lima F.W.S., Plascak J.A., Magnetic models on various topologies, J. Phys.: Conf. Ser., 487, 1, (2014); Bridson R., Fast Poisson disk sampling in arbitrary dimensions, Technical Report, (2007); Evans R.F.L., Fan W.J., Chureemart P., Ostler T.A., Ellis M.O.A., Chantrell R.W., Atomistic spin model simulations of magnetic nanoma-terials., J. Phys. Condens. Matter, 26, (2014); Evans R.F.L., Atxitia U., Chantrell R.W., Quantitative simulation of temperature-dependent magnetization dynamics and equilibrium properties of elemental ferromagnets, Phys. Rev. B, 91, 14, (2015); Johnson M.T., Bloemen P.J.H., Broeder F.J.A.D., Vries J.J.D., Magnetic anisotropy in metallic multilayers, Rep. Prog. Phys., 59, 11, pp. 1409-1458, (1999); Neumann A., Altwein D., Thonnifien C., Wieser R., Berger A., Meyer A., Vedmedenko E., Peter Oepen H., Influence of long-range interactions on the switching behavior of particles in an array of ferromagnetic nanostructures, New J. Phys., 16, 8, (2014); Weller D., Moser A., Thermal effect limits in ultrahigh-density magnetic recording, IEEE Trans. Magn., 35, 6, pp. 4423-4439, (1999); Schrenk K.J., Araujo N.A.M., Herrmann H.J., Stacked triangular lattice: percolation properties, Phys. Rev. E, 87, 3, (2013); van der Marck S.C., Percolation thresholds and universal formulas, Phys. Rev. E, 55, 2, pp. 1514-1517, (1997)","O.D. Arbeláez-Echeverri; Departamento de fisica y quimica, Universidad Nacional de Colombia – Sede Manizales, A.A. 127 Manizales, Colombia; email: odarbelaeze@unal.edu.co","","Elsevier B.V.","","","","","","13869477","","PELNF","","English","Phys E","Article","Final","","Scopus","2-s2.0-84971343337" +"Yetis H.; Denizli H.","Yetis, Hakan (6507725661); Denizli, Haluk (35227195400)","6507725661; 35227195400","Antidot effects on micromagnetic behavior of Py ferromagnetic samples","2016","Journal of Magnetism and Magnetic Materials","413","","","14","18","4","3","10.1016/j.jmmm.2016.04.023","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84963649670&doi=10.1016%2fj.jmmm.2016.04.023&partnerID=40&md5=164f3571ab537419be4b0da9cbd2eaa6","Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey","Yetis H., Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey; Denizli H., Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey","The coercivity and magnetic hysteresis behavior of permalloy (Py) samples have been studied in the presence of square arrays of the circular antidots. The open source OOMMF micromagnetic software is used to numerically solve the Landau-Lifshitz-Gilbert (LLG) equation. In calculations, Py samples are designed in such a way that they include a different number of antidot in an array which possess the same total surface area. In this way, the total Py region stayed unchanged despite the growing number of antidots in a fixed sample size. We found significant increase in the coercive field for the sample with the smallest antidot spacing. The results are discussed within the framework of superdomain (SD) and superdomain wall (SDW) formation. © 2016 Elsevier B.V. All rights reserved.","Antidots; Coercivity; Micromagnetic simulation; OOMMF; Permalloy","Coercive force; Nickel alloys; Open source software; Open systems; Antidots; Coercive field; Landau-Lifshitz-Gilbert equations; Micromagnetic simulations; OOMMF; Permalloy; Permalloy (py); Total surface area; Ferromagnetic materials","","","","","Abant Izzet Baysal Üniversitesi, AIBÜ; Scientific Research Plan Projects of Shaanxi Education Department, (2015.03.02.815)","This work was supported by the Abant Izzet Baysal University , Department of Scientific Research Projects under the contract 2015.03.02.815 .","Wang C.C., Adeyeye A.O., Magnetic and transport properties of multilayer nanoscale antidot arrays, Appl. Phys. Lett., 88, (2006); Martens S., Albrecht O., Nielsch K., Gorlitz D., Local modes and two magnon scattering in ordered permalloy antidot arrays, J. Appl. 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B, 59, pp. 6337-6343, (1999); Vavassori P., Gubbiotti G., Zangari G., Yu C.T., Yin H., Jiang H., Mankey G.J., Lattice symmetry and magnetization reversal in micron-size antidot arrays in Permalloy film, J. Appl. Phys., 91, pp. 7992-7994, (2002)","H. Yetis; Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey; email: yetis_h@ibu.edu.tr","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84963649670" +"Ferona A.M.; Camley R.E.","Ferona, Aaron M. (55208185300); Camley, Robert E. (7005900299)","55208185300; 7005900299","Nonlinear and chaotic magnetization dynamics near bifurcations of the Landau-Lifshitz-Gilbert equation","2017","Physical Review B","95","10","104421","","","","19","10.1103/PhysRevB.95.104421","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85015936240&doi=10.1103%2fPhysRevB.95.104421&partnerID=40&md5=a4d28598f44d3f0c4de83f55ebc677c2","Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, 80918, CO, United States","Ferona A.M., Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, 80918, CO, United States; Camley R.E., Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, 80918, CO, United States","The behavior of a uniformly magnetized domain of ellipsoidal shape subject to a static external field and oscillatory external driving field is analyzed near bifurcation events. The analysis includes the effects of both linear and circularly polarized driving fields and is performed using numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equation. Under a linearly polarized driving field, the LLG equation is a nonautonomous differential equation which can lead to complex magnetization motions, such as bistability, multiperiodic orbits, quasiperiodicity, and chaos. Under a circularly polarized driving field, the LLG equation can be written in autonomous form by transforming to the frame rotating with the driving field. The autonomous nature allows one to perform a fixed-point analysis of the system for select demagnetization factors. Similarities and differences between the driven systems are highlighted through bifurcation diagrams, phase portraits, basins of attraction, and Lyapunov exponents. Magnetization switching, prolonged transients, quasiperiodicity, and chaos are observed with both linearly and circularly polarized driving fields in the magnetic systems investigated. © 2017 American Physical Society.","","","","","","","","","Gilbert T.L., IEEE Trans. Magn., 40, (2004); Serpico C., Mayergoyz I., Bertotti G., D'Aquino M., Bonin R., Phys. B (Amsterdam, Neth.), 403, (2008); Mayergoyz I.D., Bertotti G., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Wei D., Micromagnetics and Recording Materials, (2012); D'Aquino M., Scholz W., Schrefl T., Serpico C., Fidler J., J. Magn. Magn. Mater., 290, (2005); Wigen P.E., Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Takano K., Zhang X., Salhi E.-A., Guan L., Sakai M., Smyth J., Dovek M., IEEE Trans. Magn., 43, (2007); Forster H., Schrefl T., Scholz W., Suess D., Tsiantos V., Fidler J., J. Magn. Magn. Mater., 249, (2002); Getzlaff M., Fundamentals of Magnetism, (2007); Osborn J., Phys. 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Instrum., 73, (2002); Kuanr B., Celinski Z., Camley R., Appl. Phys. Lett., 83, (2003); Aharoni A., J. Appl. Phys., 83, (1998)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","","Scopus","2-s2.0-85015936240" +"Wen H.-Y.; Xia J.-B.","Wen, Hong-Yu (57194171417); Xia, Jian-Bai (55557360500)","57194171417; 55557360500","Voltage control of magnetization switching and dynamics","2018","Chinese Physics B","27","6","067502","","","","0","10.1088/1674-1056/27/6/067502","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85049394126&doi=10.1088%2f1674-1056%2f27%2f6%2f067502&partnerID=40&md5=27dc1e1196f09f092409a65b4ca51926","State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","Wen H.-Y., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; Xia J.-B., State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China","The voltage controlled magnetic switching effect is verified experimentally. The Landau-Lifshitz-Gilbert (LLG) equation is used to study the voltage controlled magnetic switching. It is found that the initial values of magnetic moment components are critical for the switching effect, which should satisfy a definite condition. The external magnetic field which affects only the oscillation period should be comparable to the internal magnetic field. If the external magnetic field is too small, the switching effect will disappear. The precessions of mx and my are the best for the tilt angle of the external magnetic field qt = 0, i.e., the field is perpendicular to the sample plane. © 2018 Chinese Physical Society and IOP Publishing Ltd.","Landau-Lifshitz-Gilbert (LLG) equation; Magnetic switching; spin transfer torque; voltage control","Magnetic fields; Magnetic moments; Voltage control; External magnetic field; Internal magnetic fields; Landau-Lifshitz-Gilbert equations; Magnetic switching; Oscillation periods; Spin transfer torque; Voltage control of magnetizations; Voltage-controlled; Switching","","","","","Chinese Academy of Sciences, CAS","∗Project supported by the Advanced Research Plan of the Chinese Academy of Sciences (Grant No. QYZDY-SSW-JSC015). †Corresponding author. E-mail: xiajb@semi.ac.cn","Kudo K., Suto H., Nagasawa T., Mizushima K., Sato R., Appl. Phys. Express, 8, 10, (2015); Zhou W., Yamaji T., Seki T., Imamura H., Takanashi K., Appl. Phys. Lett., 110, (2017); Taniguchi T., Phys. 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Rep., 7, (2017); Zhang Z., Zhang Y., Zheng Z., Wang G., Su L., Zhang Y., Zhao W., AIP Adv., 7, (2017); Weisheit M., Fahler S., Marty A., Souche Y., Poinsignon C., Givord D., Science, 315, (2007); Maruyama T., Shiota Y., Nozaki T., Ohta K., Toda N., Mizuguchi M., Tulapurkar A.A., Shinjo T., Shiraishi M., Mizukami S., Ando Y., Suzuki Y., Nat. Nanotechnol., 4, (2009); Shiota Y., Nozaki T T., Bonell F., Murakami S., Shinjo T., Suzuki Y., Nat. Mater., 11, (2012); Nozaki T., Shiota Y., Miwa S., Murakami S., Bonell F., Ishibashi S., Kubota H., Yakushiji K., Saruya T., Fukushima A., Yuasa S., Shinjo T., Suzuki Y., Nat. Phys., 8, (2012); Shiota Y., Maryyama T., Nozaki T., Shinjo T., Shiraishi M., Suzuki Y., Appl. Phys. Express, 2, 6, (2009); Wen H.Y., Xia J.B., Chin. Phys., 26, 4, (2017)","J.-B. Xia; State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China; email: xiajb@semi.ac.cn","","Institute of Physics Publishing","","","","","","16741056","","","","English","Chin. Phys.","Article","Final","","Scopus","2-s2.0-85049394126" +"Praetorius D.; Ruggeri M.; Stiftner B.","Praetorius, Dirk (6507452481); Ruggeri, Michele (56196953600); Stiftner, Bernhard (57200730751)","6507452481; 56196953600; 57200730751","Convergence of an implicit–explicit midpoint scheme for computational micromagnetics","2018","Computers and Mathematics with Applications","75","5","","1719","1738","19","16","10.1016/j.camwa.2017.11.028","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85042294952&doi=10.1016%2fj.camwa.2017.11.028&partnerID=40&md5=de74b9983cfd9ad6d2db05e41562cd55","TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8-10/E101/4, Vienna, 1040, Austria","Praetorius D., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8-10/E101/4, Vienna, 1040, Austria; Ruggeri M., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8-10/E101/4, Vienna, 1040, Austria; Stiftner B., TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstr. 8-10/E101/4, Vienna, 1040, Austria","Based on lowest-order finite elements in space, we consider the numerical integration of the Landau–Lifschitz–Gilbert equation (LLG). The dynamics of LLG is driven by the so-called effective field which usually consists of the exchange field, the external field, and lower-order contributions such as the stray field. The latter requires the solution of an additional partial differential equation in full space. Following Bartels and Prohl (2006), we employ the implicit midpoint rule to treat the exchange field. However, in order to treat the lower-order terms effectively, we combine the midpoint rule with an explicit Adams–Bashforth scheme. The resulting integrator is formally of second-order in time, and we prove unconditional convergence towards a weak solution of LLG. Numerical experiments underpin the theoretical findings. © 2017 Elsevier Ltd","Finite elements; Implicit–explicit time-integration; Landau–Lifschitz–Gilbert equation; Micromagnetism; Spin-transfer torque","Finite element method; Integration; Numerical methods; Partial differential equations; Adams-Bashforth scheme; Implicit midpoint rule; Implicit-explicit time integration; Landau-Lifschitz-Gilbert equation; Micro magnetisms; Numerical integrations; Spin transfer torque; Unconditional convergence; Integral equations","","","","","Technische Universitat Wien, TU Wien; Vienna Science and Technology Fund, (MA14-44); Austrian Science Fund, (W1245)"," The authors acknowledge support of the Vienna Science and Technology fund (WWTF) under grant MA14-44 , of the Austrian Science Fund (FWF) under grant W1245 , and of TU Wien through the innovative projects initiative. We thank Alexander Rieder (TU Wien) and Alexander Haberl (TU Wien) for their help with coupling NGSolve to the BEM++ library. 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(55638392400); Liu, Ying (55899847200); Zhao, Xiuchen (8216616800)","55638392400; 55899847200; 8216616800","The hierarchical three-dimensional cobalt superstructure: Controllable synthesis, electromagnetic properties and microwave absorption","2015","Advanced Powder Technology","26","6","","1520","1528","8","19","10.1016/j.apt.2015.08.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84949626667&doi=10.1016%2fj.apt.2015.08.012&partnerID=40&md5=2d7d20be00e6e4b56443813b17578e50","School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China","Wen S.L., School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China; Liu Y., School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China; Zhao X., School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China","A close-packed hexagonal (HCP)-cobalt superstructure was synthesized on a large scale through a simple, yet low-cost liquid reduction method. The cobalt superstructure was assembled by nanoflakes with strong shape anisotropy. The permittivity (εr=ε'-jε'') and permeability (μr=μ'-jμ'') of cobalt superstructure were also studied as a function of frequency in microwave range of 1-18 GHz. It is demonstrated that permittivity displays remarkable multiple dielectric resonance peaks. Multiple magnetic resonances were also exhibited for permeability, which were discussed based on the LLG equation and exchange resonance mode. Multiple dielectric and magnetic resonances were beneficial to widen microwave absorption bandwidth. The calculated reflection loss (RL) indicated that the cobalt superstructure had potential application as a promising candidate for microwave absorption. The reflection loss was attributed to two main reasons, one is the destructive interference, which was related to the thickness of the absorbent layer, and the other one was multiple microwave reflection due to the structure assembled by nanoflakes. © 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.","Cobalt superstructure; Microwave absorption; Permeability; Permittivity","Magnetic resonance; Mechanical permeability; Microwaves; Permittivity; Resonance; Controllable synthesis; Destructive interference; Dielectric resonances; Electromagnetic properties; Function of frequency; Liquid reduction; Microwave absorption; Microwave reflection; Cobalt","","","","","","","Che R., Peng L.M., Duan X.F., Chen Q., Liang X., Microwave absorption enhancement and complex permittivity and permeability of Fe encapsulated within carbon nanotubes, Adv. 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Phys. Lett., 88, (2006); Zheng Z., Xu B., Huang L., He L., Ni X., Novel composite of Co/carbon nanotubes: Synthesis, magnetism and microwave absorption properties, Solid State Sci., 10, pp. 316-320, (2008); Liu T., Zhou P.H., Xie J.L., Deng L.J., The hierarchical architecture effect on the microwave absorption properties of cobalt composites, J. Appl. Phys., 110, (2011)","Y. Liu; School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China; email: yingliu@bit.edu.cn","","Elsevier","","","","","","09218831","","APTEE","","English","Adv Powder Technol","Article","Final","","Scopus","2-s2.0-84949626667" +"Taniguchi T.","Taniguchi, Tomohiro (36180180300)","36180180300","Synchronized, periodic, and chaotic dynamics in spin torque oscillator with two free layers","2019","Journal of Magnetism and Magnetic Materials","483","","","281","292","11","18","10.1016/j.jmmm.2019.03.090","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85064443318&doi=10.1016%2fj.jmmm.2019.03.090&partnerID=40&md5=6af3904258e35758ae139968fb2ef505","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8568, Ibaraki, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, 305-8568, Ibaraki, Japan","A phase diagram of the magnetization dynamics is studied by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation in a spin torque oscillator consisting of asymmetric two free layers that are magnetized in in-plane direction. We calculated the dynamics for a wide range of current density for both low and high field cases, and found many dynamical phases such as synchronization, auto-oscillation with different frequencies, and chaotic dynamics. The observation of the synchronization indicates the presence of a dynamical phase which has not been found experimentally by using the conventional electrical detection method. The auto-oscillations with different frequencies lead to an oscillation of magnetoresistance with a high frequency, which can be measured experimentally. The chaotic and/or periodic behavior of magnetoresistance in a high current region, on the other hand, leads to a discontinuous change of the peak frequency in Fourier spectrum. © 2019 Elsevier B.V.","chaos; Limit cycle; LLG simulation; Spin torque oscillator; Synchronization","Chaos theory; Dynamics; Magnetoresistance; Synchronization; Different frequency; Electrical detection method; In-plane direction; Landau-Lifshitz-Gilbert equations; Limit-cycle; LLG simulation; Magnetization dynamics; Spin-torque oscillators; Spin dynamics","","","","","","","Slonczewski J.C., Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier, Phys. Rev. B, 39, (1989); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. 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B, 87, (2013); Chiba T.; Suto H., Nagasawa T., Kudo K., Kanao T., Mizushima K., Sato R., Layer-selective switching of a double-layer perpendicular magnetic nanodot using microwave assistance, Phys. Rev. Appl., 5, (2016); Grollier J., Cros V., Jaffres H., Hamzic A., George J.M., Faini G., Youssef J.B., LeGall H., Fert A., Field dependence of magnetization reversal by spin transfer, Phys. Rev. B, 67, (2003); Firastrau I., Ebels U., Buda-Prejbeanu L., Toussaint J.-C., Thirion C., Dieny B., State diagram for spin current-induced magnetization dynamics using a perpendicular polarizer and a planar free layer, J. Magn. Magn. Mater., 310, (2007); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbenu-Buda L., Cyrille M.-C., Redon O., Dieny B., Spin torque oscillator using a perpendicular polarized and a planar free layer, Nat. Mater., 6, (2007); Ebels U., Houssameddine D., Firastrau I., Gusakova D., Thirion C., Dieny B., Buda-Prejbeanu L.D., Macrospin description of the perpendicular polarizer-plannar free-layer spin-torque oscillator, Phys. Rev. B, 78, (2008); Silva T.J., Keller M.W., Theory of thermally induced phase noise in spin torque oscillators for a high-symmetry case, IEEE. Trans. Magn., 46, (2010); Taniguchi T., Kubota H., Instability analysis of spin-torque oscillator with an in-plane magnetized free layer and a perpendicularly magnetized pinned layer, Phys. Rev. B, 93, (2016); Taniguchi T., Kubota H., Spin torque oscillator for microwave assisted magnetization reversal, Jpn. J. Appl. Phys., 57, (2018); Vonsovskii S.V., Ferromagnetic Resonance, (1966); Taniguchi T., Ito T., Tsunegi S., Kubota H., Utsumi Y., Relaxation time and critical slowing down of a spin-torque oscillator, Phys. Rev. B, 96, (2017)","","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85064443318" +"Li J.; Yang Q.; Li Y.","Li, Jingsong (55273220100); Yang, Qingxin (7404076426); Li, Yongjian (56162279800)","55273220100; 7404076426; 56162279800","Losses Modeling Based on Domain Wall Processes and Validation Considering Rotational Excitation of Electrical Steel Sheets","2018","IEEE Transactions on Magnetics","54","11","4300205","","","","0","10.1109/TMAG.2018.2844028","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85049070128&doi=10.1109%2fTMAG.2018.2844028&partnerID=40&md5=d4bffa3782d138685141035e6563f85f","State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing, 100084, China; Municipal Key Laboratory of Advanced Technology of Electrical Engineering and Energy, Tianjin Polytechnic University, Tianjin, 300387, China; State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300130, China","Li J., State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing, 100084, China; Yang Q., Municipal Key Laboratory of Advanced Technology of Electrical Engineering and Energy, Tianjin Polytechnic University, Tianjin, 300387, China, State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300130, China; Li Y., State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, 300130, China","The domain wall processes are investigated and modeled at low-to-medium frequencies in electrical steel sheets based on the damping principle of vibration. Due to the energy dissipation chiefly descends from a micro-vortex current caused by domain wall motion, the coupled Landau-Lifshitz-Gilbert and Maxwell electromagnetic diffusion equations are thus considered to describe the high-frequency characteristics. The overall core losses are eventually deduced in terms of separate contributions by domain wall processes and classical eddy current. Moreover, the calculation model can be extended to rotational excitation pattern. Hence, taking typical electrical steel sheets as example, the novel core loss calculation model is analyzed and compared with the total alternating core losses supplied by electrical steel sheet manufacturers and the 3-D rotating experimental core losses of testing sheets which are carried out by using a 3-D magnetic properties' testing system, and also achieve some beneficial conclusions. © 1965-2012 IEEE.","3-D rotating core losses; domain wall processes; electrical steel sheets; Landau-Lifshitz-Gilbert (LLG) and Maxwell electromagnetic diffusion equations; micro-vortex current","Domain walls; Energy dissipation; Magnetic cores; Maxwell equations; Silicon steel; Steel sheet; Vortex flow; Core loss; Core loss calculation; Diffusion equations; Electrical steel sheets; High frequency characteristics; Landau-Lifshitz-Gilbert; Micro vortex; Rotational excitation; Steel testing","","","","","National Natural Science Foundation of China, NSFC, (51237005); National Natural Science Foundation of China, NSFC","ACKNOWLEDGMENT This work was supported by the Key Project of National Natural Science Foundation of China under Grant 51237005. Jingsong Li, Qingxin Yang, and Yongjian Li contributed equally to this work.","Bertotti G., Some considerations on the physical interpretation of eddy current losses in ferromagnetic materials, J. Magn. Magn. Mater., Vols., 54-57, pp. 1556-1560, (1986); Zhu J.G., Ramsden V.S., Improved formulations for rotational core losses in rotating electrical machines, IEEE Trans. Magn., 34, 4, pp. 2234-2242, (1998); Bertotti G., General properties of power losses in soft ferromagnetic materials, IEEE Trans. Magn., MAG-24, 1, pp. 621-630, (1988); Bertotti G., Fiorillo F., Mazzetti P., Basic principles of magnetization processes and origin of losses in soft magnetic materials, J. Magn. Magn. Mater, 112, 1-3, pp. 146-149, (1992); Li Y., Yang Q., Zhu J., Guo Y., Magnetic properties mea-surement of soft magnetic composite materials over wide range of excitation frequency, IEEE Trans. Ind. Appl, 48, 1, pp. 88-97, (2012); Li Y., Yang Q., Zhu J., Zhao Z., Liu X., Zhang C., Design and analysis of a novel 3-D magnetization structure for laminated silicon steel, IEEE Trans. Magn., 50, 2, (2014); Landau B.L.D., Lifshitz E.M., Electrodynamics of Continuous Media (Course of Theoretical Physics S), 8, pp. 199-224, (1984); Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetization field, Phys. Rev., 100, 52, (1955); Bottauscio O., Fiorillo F., Beatrice C., Caprile A., Magni A., Modeling high-frequency magnetic losses in transverse anisotropy amorphous ribbons, IEEE Trans. Magn., 51, 3, (2015); Rado G.T., On the inertia of oscillating ferromagnetic domain walls, Phys. Rev., 83, 4, pp. 821-826, (1951); Li J., Yang Q., Li Y., Zhang C., Qu B., Cao L., Anomalous loss modeling and validation of magnetic materials in electrical engineering, IEEE Trans. Appl. Supercond., 26, 4, (2016); Bereznicki M., The influence of skin effect on the accuracy of eddy current energy loss calculation in electrical steel sheets, Proc. IEEE Conf. Sel. Problems Elect. Eng. Electron. (WZEE), Sep., pp. 1-4, (2015); Mueller M.A., Calculation of iron losses from time-stepped finite-element models of cage induction machines, Proc. 7th Int. Conf. Elect. Mach. Drives (EMD), 412, pp. 88-92, (1995); Wuhan Iron and Steel (Group) Company: WUSTEEL Cold-Rolled GO Electrical Steel, (2010); Baosteel: BAOSTEEL Cold-Rolled NO Electrical Steel, (2009)","J. Li; State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing, 100084, China; email: lijingsong@mail.tsinghua.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85049070128" +"Perach B.; Kvatinsky S.","Perach, Ben (57201677450); Kvatinsky, Shahar (36866322000)","57201677450; 36866322000","STT-ANGIE: Asynchronous True Random Number GEnerator Using STT-MTJ","2019","Proceedings of the 2019 Design, Automation and Test in Europe Conference and Exhibition, DATE 2019","","","8715257","264","267","3","5","10.23919/DATE.2019.8715257","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85066608192&doi=10.23919%2fDATE.2019.8715257&partnerID=40&md5=df505d7aae117dc2e553f0e034ab91d5","Viterbi Faculty of Electrical Engineering, Technion - Israel Institute of Technology, Haifa, Israel","Perach B., Viterbi Faculty of Electrical Engineering, Technion - Israel Institute of Technology, Haifa, Israel; Kvatinsky S., Viterbi Faculty of Electrical Engineering, Technion - Israel Institute of Technology, Haifa, Israel","The Spin Transfer Torque Magnetic Tunnel Junction (STT-MTJ) is an emerging memory technology whose interesting stochastic behavior might benefit security applications. In this paper, we leverage this stochastic behavior to construct a true random number generator (TRNG), the basic module in the process of encryption key generation. Our proposed TRNG operates asynchronously and thus can use small and fast STT MTJ devices. As such, it can be embedded in low-power and low-frequency devices without loss of entropy. We evaluate the proposed TRNG using a numerical simulation, solving the Landau-Lifshitz-Gilbert (LLG) equation system of the STT-MTJ devices. Design considerations, attack analysis, and process variation are discussed and evaluated. The evaluation shows that our solution is robust to process variation, achieving a Shannon-entropy generating rate between 99.7Mbps and 127.8Mbps for 90% of the instances. © 2019 EDAA.","memristors; MRAM; security; STT-MTJ; TRNG","Cryptography; Magnetic devices; Memristors; MRAM devices; Number theory; Stochastic systems; Tunnel junctions; Design considerations; Emerging memory technologies; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; MRAM; security; STT-MTJ; TRNG; Random number generation","","","","","Israel Cyber Bureau; Technion Computer Engineering Center, (CG679001); Technion Hiroshi Fujiwara Cyber Security Research Center","ACKNOWLEDGMENTS This research was partially supported by the Viterbi Fellowship at the Technion Computer Engineering Center, by Cisco grant no. CG679001, by the Technion Hiroshi Fujiwara Cyber Security Research Center, and by the Israel Cyber Bureau.","Vatajelu E.I., Et al., Stt-mtj-based trng with on-The-fly temperature/current variation compensation, IOLTS, (2016); Fukushima A., Et al., Spin dice: A scalable truly random number generator based on spintronics, Appl. Phys. Express, 7, 8, (2014); Oosawa S., Et al., Design of an stt-mtj based true random number generator using digitally controlled probability-locked loop, NEWCAS, (2015); Ghosh S., Spintronics and security: Prospects, vulnerabilities, attack models, and preventions, Proc. IEEE, 104, 10, pp. 1864-1893, (2016); Vadhan S.P., Pseudorandomness, Found. Trends Theor. Comput. Sci., 7, 1-3, pp. 1-336, (2012); Devolder T., Et al., Single-shot time-resolved measurements of nanosecond-scale spin-Transfer induced switching: Stochastic versus deterministic aspects, Phys. Rev. Lett., 100, (2008); Vincent A.F., Et al., Analytical macrospin modeling of the stochastic switching time of spin-Transfer torque devices, IEEE Trans. Electron Devices, 62, 1, pp. 164-170, (2015); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Garcia-Palacios, Et al., Langevin-dynamics study of the dynamical properties of small magnetic particles, Phys. Rev. B, 58, pp. 14937-14958, (1998); Slonczewski J., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1, pp. L1-L7, (1996); D'Aquino M., Et al., Midpoint numerical technique for stochastic landau-lifshitz-gilbert dynamics, J. Appl. Phys., 99, 8, (2006); Yamada K., Anisotropic magnetic shielding effectiveness of magnetic shielded package, IEEE Trans. Magn., 53, 11, pp. 1-4, (2017); Wang W., Et al., Magnetic shielding design for magneto-electronic devices protection, IEEE Trans. Magn., 44, 11, pp. 4175-4178, (2018); Goode D., Et al., The demagnetizing energies of a uniformly magnetized cylinder with an elliptic cross-section, J. Magn. Magn. Mater., 267, 3, pp. 373-385, (2003); Li J., Et al., Modeling of failure probability and statistical design of spin-Torque transfer magnetic random access memory (stt mram) array for yield enhancement, DAC, (2008); Dong Q., Et al., A 1mb 28nm stt-mram with 2.8ns read access time at 1.2v vdd using single-cap offset-cancelled sense amplifier and in-situ self-write-Termination, ISSCC, (2018); Yang K., Et al., 16.3 A 23Mb/s 23pJ/b Fully Synthesized True-Random-Number Generator in 28nm and 65nm CMOS, ISSCC, (2014); Srinivasan S., Et al., 2.4GHz 7mW All-Digital PVT-Variation Tolerant True Random Number Generator in 45nm CMOS, Symposium on VLSI Circuits, (2010)","","","Institute of Electrical and Electronics Engineers Inc.","ACM Special Interest Group on Design Automation (SIGDA); Electronic System Design (ESD) Alliance; et al.; European Design and Automation Association (EDAA); European Electronic Chips and Systems Design Initiative (ECSI); IEEE Council on Electronic Design Automation (CEDA)","22nd Design, Automation and Test in Europe Conference and Exhibition, DATE 2019","25 March 2019 through 29 March 2019","Florence","148080","","978-398192632-3","","","English","Proc. Des., Autom. Test Europe Conf. Exhib., DATE","Conference paper","Final","","Scopus","2-s2.0-85066608192" +"Müller G.P.; Hoffmann M.; Dißelkamp C.; Schürhoff D.; Mavros S.; Sallermann M.; Kiselev N.S.; Jónsson H.; Blügel S.","Müller, Gideon P. (57213539017); Hoffmann, Markus (57199660443); Dißelkamp, Constantin (57209286463); Schürhoff, Daniel (57195412859); Mavros, Stefanos (57209278699); Sallermann, Moritz (57209284311); Kiselev, Nikolai S. (23110650400); Jónsson, Hannes (22971441100); Blügel, Stefan (10640602400)","57213539017; 57199660443; 57209286463; 57195412859; 57209278699; 57209284311; 23110650400; 22971441100; 10640602400","Spirit: Multifunctional framework for atomistic spin simulations","2019","Physical Review B","99","22","224414","","","","135","10.1103/PhysRevB.99.224414","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85067192577&doi=10.1103%2fPhysRevB.99.224414&partnerID=40&md5=55e9f9835d1bb6a441afd8c0c01d9be7","Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany; Science Institute, Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík, 107, Iceland; Department of Physics, RWTH Aachen University, Aachen, 52056, Germany","Müller G.P., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany, Science Institute, Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík, 107, Iceland, Department of Physics, RWTH Aachen University, Aachen, 52056, Germany; Hoffmann M., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany; Dißelkamp C., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany, Department of Physics, RWTH Aachen University, Aachen, 52056, Germany; Schürhoff D., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany, Department of Physics, RWTH Aachen University, Aachen, 52056, Germany; Mavros S., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany, Department of Physics, RWTH Aachen University, Aachen, 52056, Germany; Sallermann M., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany; Kiselev N.S., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany; Jónsson H., Science Institute, Faculty of Physical Sciences, University of Iceland, VR-III, Reykjavík, 107, Iceland; Blügel S., Peter Grünberg Institut, Institute for Advanced Simulation, Forschungszentrum Jülich, JARA, Jülich, 52425, Germany","The Spirit framework is designed for atomic-scale spin simulations of magnetic systems with arbitrary geometry and magnetic structure, providing a graphical user interface with powerful visualizations and an easy-to-use scripting interface. An extended Heisenberg-type spin-lattice Hamiltonian including competing exchange interactions between neighbors at arbitrary distances, higher-order exchange, Dzyaloshinskii-Moriya and dipole-dipole interactions is used to describe the energetics of a system of classical spins localized at atom positions. A variety of common simulation methods are implemented including Monte Carlo and various time evolution algorithms based on the Landau-Lifshitz-Gilbert (LLG) equation of motion. These methods can be used to determine static ground-state and metastable spin configurations, sample equilibrium and finite-temperature thermodynamical properties of magnetic materials and nanostructures, or calculate dynamical trajectories including spin torques induced by stochastic temperature or electric current. Methods for finding the mechanism and rate of thermally assisted transitions include the geodesic nudged elastic band method, which can be applied when both initial and final states are specified, and the minimum mode-following method when only the initial state is given. The lifetimes of magnetic states and rates of transitions can be evaluated within the harmonic approximation of transition-state theory. The framework offers performant central processing unit (CPU) and graphics processing unit (GPU) parallelizations. All methods are verified and applications to several systems, such as vortices, domain walls, skyrmions, and bobbers are described. © 2019 American Physical Society.","","Computer graphics; Computer graphics equipment; Domain walls; Equations of motion; Evolutionary algorithms; Graphical user interfaces; Graphics processing unit; Ground state; Hamiltonians; Magnetic structure; Magnetism; Program processors; Stochastic systems; Dipole dipole interactions; Dzyaloshinskii-moriya; Harmonic approximation; Higher-order exchange; Landau-Lifshitz-Gilbert equations; Nudged elastic band methods; Thermodynamical properties; Transition state theories; Monte Carlo methods","","","","","Icelandic Research Fund, (184949-051, 185405-051); Horizon 2020 Framework Programme, H2020, (665095)"," The authors acknowledge helpful discussions with Pavel Bessarab, Stephan von Malottki, Jan Müller, Jonathan Chico, Filipp N. Rybakov, and Florian Rhiem. G.P.M. acknowledges funding by the Icelandic Research Fund (Grants No. 185405-051 and No. 184949-051) and M.H. and S.B. acknowledge funding from MAGicSky Horizon 2020 European Research FET Open Project (No. 665095) and from the DARPA TEE program through Grant MIPR (No. HR0011831554) from DOI. The work of N.S.K. was supported by Deutsche Forschungsgemeinschaft (DFG) via SPP 2137 “Skyrmionics” Grant No. KI 2078/1-1. ","Hoffmann M., Zimmermann B., Muller G.P., Schurhoff D., Kiselev N.S., Melcher C., Blugel S., Antiskyrmions stabilized at interfaces by anisotropic Dzyaloshinskii-Moriya interactions, Nat. Commun., 8, (2017); Zutic I., Fabian J., Das Sarma S., Spintronics: Fundamentals and applications, Rev. Mod. Phys., 76, (2004); Bader S.D., Opportunities in nanomagnetism, Rev. Mod. 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Theory Comput., 13, (2017)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85067192577" +"Takeda S.; Kijima-Aoki H.; Masumoto H.; Suzuki H.","Takeda, S. (8222172300); Kijima-Aoki, H. (52363714500); Masumoto, H. (35432613600); Suzuki, H. (15926596700)","8222172300; 52363714500; 35432613600; 15926596700","Permeability measurement up to 30 ghz of a magnetically isotropic thin film using a short-circuited coaxial line","2019","Journal of the Magnetics Society of Japan","43","5","","91","98","7","2","10.3379/msjmag.1909R001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85073349765&doi=10.3379%2fmsjmag.1909R001&partnerID=40&md5=930586249858aa870cc59af24797b136","Magnontech Ltd., 787-16 Jurokken, Kumagaya, 360-0846, Saitama, Japan; Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, 980-8578, Japan; KEYCOM Corp., 3-39-14, Minami Ohtsuka, Toshima-ku, Tokyo, 170-0005, Japan","Takeda S., Magnontech Ltd., 787-16 Jurokken, Kumagaya, 360-0846, Saitama, Japan, KEYCOM Corp., 3-39-14, Minami Ohtsuka, Toshima-ku, Tokyo, 170-0005, Japan; Kijima-Aoki H., Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, 980-8578, Japan; Masumoto H., Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, 980-8578, Japan; Suzuki H., KEYCOM Corp., 3-39-14, Minami Ohtsuka, Toshima-ku, Tokyo, 170-0005, Japan","In this study, the high frequency permeability (µ) and ferromagnetic resonance(FMR) phenomena of a thin film with a strong perpendicular magnetic anisotropy and in-plane magnetically isotropic properties was measured using the short-circuited coaxial line technique; the analyzed sample had a toroidal shape. A field method was used for the background correction, where a strong magnetic bias field was applied and removed. However, when using a short-circuited coaxial line, the µ =1 condition cannot be achieved beyond a few ten GHz frequencies, whereas ferromagnetic resonance (denoted as FMR2) occurred because of the insufficient bias field. This resonance was compensated using the Landau-Lifshitz-Gilbert (LLG) equation, and the net µ-f properties without the bias field (denoted as FMR1) up to 30 GHz successfully extracted. Finally, a good agreement between the experimental results and the calculations based on the assumption of a magnetic multi-domain structure in FMR1 was achieved. © 2019, Magnetics Society of Japan. All rights reserved.","Ferromagnetic resonance; FMR; GHz band; LLG; Magnetic thin film; Permeability measurement; Perpendicular anisotropy; Short-circuited coaxial line; Wideband measurement","Coaxial cables; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic anisotropy; Magnetic circuits; Magnetic thin films; Microstrip lines; Microwave circuits; Timing circuits; Coaxial line; GHz band; Permeability measurements; Perpendicular anisotropy; Wideband measurements; Thin film circuits","","","","","Japan Society for the Promotion of Science, JSPS, (17H03385, 18H05936)","Acknowledgements This work has been funded by the Japan Society for the Promotion of Science (JSPS) KAKENHI under Grand-in-aid No. 17H03385 and 18H05936. We are grateful to rD . Miyazaki of Tohoku University for his kind support to TEM observation. We thank Prof. M. Yamaguchi of Tohoku University, and D r. M. Naoe of Research Institute for Electro-magnetic materials, for their useful discussions and supportive advices. We wish to thank Mr. T. Hotchi, Mr. S. Motomura, Mr. S. Yamasaki, and Dr. M. Taguchi of KEYCOM corp. for his kind assistant and useful experimental suggestions. The authors would like to thank Enago for the English language review.","Takeda S., Hotchi T., Motomura S., Suzuki H., J. Magn. Soc. Jpn., 39, (2015); Takeda S., Naoe M., J. Magn. Magn. Mater, 449, (2018); Weir W.B., Proc. IEEE, 62, 1, (1974); Nicolson A.M., IEEE. Trans. Instrum, Meas. IM-17, (1968); Kijima H., Ohnuma S., Masumoto H., J. Magn. Soc. Jpn., 36, (2012); Kijima H., Zhang Y., Kobayashi N., Ohnuma S., Masumoto H., IEEE. Trans. Magn., 48, (2012); Naoe M., Kobayashi N., Ohnuma S., Watanabe M., Iwasa T., Masumoto H., IEEE Magn., Lett., 5, (2014); Kijima-Aoki H., Takeda S., Ohnuma S., Masumoto H., IEEE Magn., Lett., 9, (2018); Takeda S., Motomura S., Hotch T., Suzuki H., J. Magn. Soc. Jpn., 39, (2015); Takeda S., Suzuki H., J. Magn. Soc. Jpn., 33, (2009); Takeda S., Motomura S., Hotch T., Suzuki H., J. Jpn. Soc. of Powder and Powder Metallurgy, 61, (2014); Pozar D.M., Microwave Engineering, (1998); Kittel C., Phys. Rev., 73, 2, (1948); Smit J., Wijn H.P.J., Ferrites,” Philips Technical Library, (1965)","","","Magnetics Society of Japan","","","","","","02850192","","","","English","J. Magnetics Soc. Japan","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85073349765" +"Blachowicz T.; Ehrmann A.","Blachowicz, T. (55903481800); Ehrmann, A. (36678640500)","55903481800; 36678640500","Micromagnetic investigation of low-symmetry 3D particles","2017","IOP Conference Series: Materials Science and Engineering","175","1","012057","","","","1","10.1088/1757-899X/175/1/012057","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85016477502&doi=10.1088%2f1757-899X%2f175%2f1%2f012057&partnerID=40&md5=1147fe5dea74bbec5efd8cee7923fdc8","Institute of Physics, Center for Science and Education, Silesian University of Technology, Gliwice, 44-100, Poland; Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, 33619, Germany","Blachowicz T., Institute of Physics, Center for Science and Education, Silesian University of Technology, Gliwice, 44-100, Poland; Ehrmann A., Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, 33619, Germany","Investigating the anisotropies of magnetic nanoparticles is crucial for further development of magnetic data storage media, MRAM, magnetic logical circuits, or magnetic quantum cellular automata. Former theoretical and experimental examinations have revealed the possibility to gain highly symmetric nanoparticles with increased numbers of magnetic states per storage element. In a recent project, we have investigated low-symmetry T-shaped 2D and 3D particles from iron using the micromagnetic simulation software MAGPAR which is based on solving the Landau-Lifshitz-Gilbert (LLG) equation of motion for a mesh built from tetrahedral finite elements. To examine the influence of the reduced symmetry, simulations were performed on the 3D double-T particle with the field applied in different directions in the x-y base plane, ranging from 0 to 180° in 5° steps. Additionally, the external magnetic field was rotated laterally under different angles with respect to the x-y plane, i.e. 5°, 22.5°, and 45°. Similar simulations were executed for the 2D single-T particle. Our results show the strong impact of the shape anisotropy and the respective possibility to tailor magnetic anisotropies according to the desired behaviour by modifying the nanoparticles' form. © Published under licence by IOP Publishing Ltd.","","Anisotropy; Computer software; Digital storage; Equations of motion; Finite element method; Integrated circuits; Magnetic bubbles; Magnetism; MRAM devices; Nanomagnetics; Nanoparticles; Experimental examination; External magnetic field; Landau-Lifshitz-Gilbert equations; Magnetic data storage media; Magnetic nano-particles; Magnetic quantum cellular automaton; Micromagnetic simulations; Tetrahedral finite elements; Magnetic storage","","","","","","","Nogues J., Sort J., Langlais V., Skumryev V., Surinach S., Munoz J.S., Baro M.D., Phys. Rep., 422, 3, (2005); Zhang W., Haas S., Phys. Rev. B, 81, 6, (2010); Zhu F.Q., Fan D.L., Zhu X.C., Zhu J.G., Cammarata R.C., Chien C.L., Adv. Mater., 16, 23-24, (2004); Subramani A., Geerpuram D., Domanowski A., Baskaran V., Metlushko V., Physica C, 404, 1-4, (2004); Wang J., Adeyeye A.O., Singh N., Appl. Phys. Lett., 87, 26, (2005); Gao X.S., Adeyeye A.O., Goolaup S., Singh N., Jung W., Castano F.J., Ross C.A., J. Appl. Phys., 101, 9, (2007); Vavassori P., Grimsditch M., Novosad V., Metlushko V., Ilic B., Phys. Rev. B, 67, 13, (2003); Soares M.M., De Biasi E., Coelho L.N., Dos Santos M.C., De Menezes F.S., Knobel M., Sampaio L.C., Garcia F., Phys. Rev. B, 77, 22, (2008); Leong T.G., Zarafshar A.M., Gracias D.H., Small, 6, 7, (2010); Amaladass E., Ludescher B., Schutz G., Tyliszczak T., Lee M.S., Eimuller T., J. Appl. Phys., 107, 5, (2010); Blachowicz T., Ehrmann A., J. Appl. Phys., 110, 7, (2011); Tillmanns A., Oertker S., Beschoten B., Guntherodt G., Leighton C., Schuller I.K., Nogues J., Appl. Phys. Lett., 89, 20, (2006); Blachowicz T., Ehrmann A., Steblinski P., Palka J., J. Appl. Phys., 113, 1, (2013); Ehrmann A., Blachowicz T., Komraus S., Nees M.K., Jakobs P.J., Leiste H., Mathes M., Schaarschmidt M., J. Appl. Phys., 117, 17, (2015); Blachowicz T., Ehrmann A., J. Magn. Magn. Mat., 331, pp. 21-23, (2013); Scholz W., Fidler J., Schrefl T., Suess D., Dittrich R., Forster H., Tsiantos V., Comp. Mat. Sci., 28, 2, (2003)","","","Institute of Physics Publishing","","4th International Conference on Competitive Materials and Technology Processes, IC-CMTP 2016","3 October 2016 through 7 October 2016","Miskolc-Lillafured","126872","17578981","","","","English","IOP Conf. Ser. Mater. Sci. Eng.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-85016477502" +"Xue D.; Ma W.","Xue, Dong (57190945490); Ma, Weiguang (8345481100)","57190945490; 8345481100","Magnetic switching of a stoner-wohlfarth particle subjected to a perpendicular bias field","2019","Electronics (Switzerland)","8","3","366","","","","4","10.3390/electronics8030366","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85064641671&doi=10.3390%2felectronics8030366&partnerID=40&md5=9549d9c56eab083e3dd91ffd5720993a","Department of Physics and Astronomy, Texas Tech University, Lubbock, 79409-1051, TX, United States; Department of Physics, Umeå University, Umeå, 90187, Sweden","Xue D., Department of Physics and Astronomy, Texas Tech University, Lubbock, 79409-1051, TX, United States; Ma W., Department of Physics, Umeå University, Umeå, 90187, Sweden"," Characterized by uniaxial magnetic anisotropy, the Stoner-Wohlfarth particle experiences a change in magnetization leading to a switch in behavior when tuned by an externally applied field, which relates to the perpendicular bias component (h perp ) that remains substantially small in comparison with the constant switching field (h 0 ). The dynamics of the magnetic moment that governs the magnetic switching is studied numerically by solving the Landau-Lifshitz-Gilbert (LLG) equation using the Mathematica code without any physical approximations; the results are compared with the switching time obtained from the analytic method that intricately treats the non-trivial bias field as a perturbation. A good agreement regarding the magnetic switching time (t s ) between the numerical calculation and the analytic results is found over a wide initial angle range (0.01 < θ 0 < 0.3), as h 0 and h perp are 1.5 × K and 0.02 × K, where K represents the anisotropy constant. However, the quality of the analytic approximation starts to deteriorate slightly in contrast to the numerical approach when computing t s in terms of the field that satisfies h perp > 0.15 × K and h 0 = 1.5 × K. Additionally, existence of a comparably small perpendicular bias field (h perp << h 0 ) causes t s to decrease in a roughly exponential manner when h perp increases. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.","Anisotropy; Bias field; Landau-Lifshitz-Gilbert equation; Stoner-Wohlfarth particle","","","","","","","","Xi H., White R.M., Coupling between two ferromagnetic layers separated by an antiferromagnetic layer, Phys. Rev. B, 62, (2000); Lee J., Kim S., Jeong J., Kim J., Shin S., In situ vectorial magnetization study of ultrathin magnetic films using a surface magneto-optical Kerr effect measurement system, IEEE Trans. Magn., 37, pp. 2773-2775, (2001); Chen Y., Lin Y., Chen D., Yao Y., Lee S., Liou Y., Current-assisted magnetization switching in submicron permalloy S-shape wires with narrow junctions, J. Appl. Phys., 97, (2005); Wegrowe J.E., Drouhin H.J., From spin diffusion to magnetization reversal: The four-channel approach. 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Rev., 120, (1960); Lu Y., Altman R.A., Rishton S.A., Trouilloud P.L., Xiao G., Gallagher W.J., Parkin S.S.P., Shape-anisotropy-controlled magnetoresistive response in magnetic tunnel junctions, Appl. Phys. Lett., 70, pp. 2610-2612, (1997); Fan X., Xue D., Jiang C., Gong Y., Li J., An approach for researching uniaxial anisotropy magnet: Rotational magnetization, J. Appl. Phys., 102, (2007); Schmalhorst J., Bruckl H., Reiss G., Kinder R., Gieres G., Wecker J., Switching stability of magnetic tunnel junctions with an artificial antiferromagnet, Appl. Phys. Lett., 77, pp. 3456-3458, (2000); de Campos M.F., da Silva F.A.S., Perigo E.A., de Castro J.A., Stoner-Wohlfarth model for the anisotropic case, J. Magn. Magn. Mater., 345, pp. 147-152, (2013); Atherton D.L., Beattie J.R., A mean field Stoner-Wohlfarth hysteresis model, IEEE Trans. Magn., 26, pp. 3059-3063, (1990); Thiaville A., Coherent rotation of magnetization in three dimensions: A geometrical approach, Phys. Rev. B, 61, (2000); Chen W., Qian L., Xiao G., Deterministic Current Induced Magnetic Switching Without External Field Using Giant Spin Hall Effect of β-W, Sci. Rep., 8, (2018); Stupakiewicz A., Szerenos K., Afanasiev D., Kirilyuk A., Kimel A.V., Ultrafast photo-magnetic recording in transparent medium, Nature, 542, pp. 71-74, (2016); Uesaka Y., Endo H., Takahashi T., Nakatani Y., Hayashi N., Fukushima H., Numerical simulation of switching time of magnetic particle, Phys. Status Solidi A, 189, pp. 1023-1027, (2002); Belmeguenai M., Devolder T., Chappert C., Analytical solution for precessional magnetization switching in exchange biased high perpendicular anisotropy nanostructures, J. Phys. D Appl. Phys., 39, 1, (2005); Poperechny I.S., Raikher Y.L., Stepanov V.I., Dynamic magnetic hysteresis in single-domain particles with uniaxial anistropy. Phys, Rev. B, (2010); Wolfram Research: Champaign","D. Xue; Department of Physics and Astronomy, Texas Tech University, Lubbock, 79409-1051, United States; email: dong.xue@ttu.edu","","MDPI AG","","","","","","20799292","","","","English","Electronics (Switzerland)","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85064641671" +"Ghosh R.; Maiti M.; Shukrinov Y.M.; Sengupta K.","Ghosh, Roopayan (55545862228); Maiti, Moitri (57216062575); Shukrinov, Yury M. (6603318620); Sengupta, K. (7103231159)","55545862228; 57216062575; 6603318620; 7103231159","Magnetization-induced dynamics of a Josephson junction coupled to a nanomagnet","2017","Physical Review B","96","17","174517","","","","16","10.1103/PhysRevB.96.174517","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85038597789&doi=10.1103%2fPhysRevB.96.174517&partnerID=40&md5=2e7f92bb1dbbf250acdef949245e306c","Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India; BLTP, JINR, Dubna, Moscow region, 141980, Russian Federation; Faculty of Natural and Engineering Sciences, Dubna State University, Dubna, 141980, Russian Federation","Ghosh R., Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India; Maiti M., BLTP, JINR, Dubna, Moscow region, 141980, Russian Federation; Shukrinov Y.M., BLTP, JINR, Dubna, Moscow region, 141980, Russian Federation, Faculty of Natural and Engineering Sciences, Dubna State University, Dubna, 141980, Russian Federation; Sengupta K., Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India","We study the superconducting current of a Josephson junction (JJ) coupled to an external nanomagnet driven by a time-dependent magnetic field both without and in the presence of an external ac drive. We provide an analytic, albeit perturbative, solution for the Landau-Lifshitz (LL) equations governing the coupled JJ-nanomagnet system in the presence of a magnetic field with arbitrary time dependence oriented along the easy axis of the nanomagnet's magnetization and in the limit of weak dimensionless coupling ϵ0 between the JJ and the nanomagnet. We show the existence of Shapiro-type steps in the I-V characteristics of the JJ subjected to a voltage bias for a constant or periodically varying magnetic field and explore the effect of rotation of the magnetic field and the presence of an external ac drive on these steps. We support our analytic results with exact numerical solution of the LL equations. We also extend our results to dissipative nanomagnets by providing a perturbative solution to the Landau-Lifshitz-Gilbert (LLG) equations for weak dissipation. We study the fate of magnetization-induced Shapiro steps in the presence of dissipation both from our analytical results and via numerical solution of the coupled LLG equations. We discuss experiments which can test our theory. © 2017 American Physical Society.","","","","","","","DST/RFBR, (INT/RUS/RFBR/P-249); Council of Scientific and Industrial Research, India, CSIR, (16-52-45011); Russian Foundation for Basic Research, РФФИ, (15-29-01217)","K.S. acknowledges DST/RFBR Grant No. INT/RUS/RFBR/P-249. R.G. acknowledges SPM fellowship from CSIR for financial support. The reported study was funded by RFBR according to the research Projects No. 15-29-01217 and No. 16-52-45011, India.","Likharev K.K., Rev. Mod. Phys., 51, (1979); Dynamics of Josephson Junctions and Circuits, (1986); Kitaev A., Phys. Usp., 44, (2001); Kwon H.-J., Sengupta K., Yakovenko V.M., Eur. Phys. J. B, 37, (2004); Lutchyn R.M., Sau J.D., Das Sarma S., Phys. Rev. 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Phys., 77, (2005); Buzdin A.I., Phys. Rev. Lett., 101, (2008); Konschelle F., Buzdin A., Phys. Rev. Lett., 102, (2009); Shukrinov Y.M., Rahmonov I.R., Sengupta K., Buzdin A., Appl. Phys. Lett., 110, (2017); Waintal X., Brouwer P.W., Phys. Rev. B, 65, (2002); Kulagina I., Linder J., Phys. Rev. B, 90, (2014); Linder J., Yokoyama T., Phys. Rev. B, 83, (2011); Holmqvist C., Teber S., Fogelstrom M., Phys. Rev. B, 83, (2011); Wernsdorfer W., Adv. Chem. Phys., 118, (2001); Wernsdorfer W., Supercond. Sci. Technol., 22, (2009); Thirion C., Wernsdorfer W., Mailly D., Nat. Mater., 2, (2003); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Zhu J.-X., Balatsky A.V., Phys. Rev. B, 67, (2003); Ma P.-W., Dudarev S.L., Phys. Rev. B, 86, (2012); Atxitia U., Chubykalo-Fesenko O., Chantrell R.W., Nowak U., Rebei A., Phys. Rev. Lett., 102, (2009); Bose T., Trimper S., Phys. Rev. B, 81, (2010); Coffey W., Kalmykov Yu.P., Waldron J.T., The Langevin Equation, (2004)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85038597789" +"Hane Y.; Nakamura K.","Hane, Yoshiki (36632081800); Nakamura, Kenji (55516112700)","36632081800; 55516112700","Hysteresis Modeling of Magnetic Devices based on Reluctance Network Analysis","2018","2018 International Power Electronics Conference, IPEC-Niigata - ECCE Asia 2018","","","8507646","2426","2429","3","2","10.23919/IPEC.2018.8507646","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85057308660&doi=10.23919%2fIPEC.2018.8507646&partnerID=40&md5=6ca45a6d508476de65f4602ea00e65bb","Graduate School of Engineering, Tohoku University, Sendai, Japan","Hane Y., Graduate School of Engineering, Tohoku University, Sendai, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, Sendai, Japan","In research and development of electrical machines, establishment of a method for quantitatively calculating iron loss including magnetic hysteresis behavior is required. In a previous paper, a novel magnetic circuit model incorporating a play model, which is one of the phenomenological models of magnetic hysteresis, was proposed. It was clear that the proposed model can calculate the hysteresis loop of the magnetic reactor with high speed and accuracy. This paper describes that the play model is applied to reluctance network analysis (RNA), in order to estimate the iron loss of electric machines with more complex shape such as electric motors. © 2018 IEEJ Industry Application Society.","Landau-Lifshitz-Gilbert (LLG) equation; magnetic circuit model; play model; reluctance network analysis (RNA)","Circuit simulation; Electric losses; Electric machinery; Iron; Iron research; Magnetic hysteresis; Magnetic materials; Magnetism; Power electronics; RNA; Electrical machine; Hysteresis modeling; Landau-Lifshitz-Gilbert equations; Magnetic circuit model; Phenomenological models; Play model; Reluctance network analysis; Research and development; Magnetic circuits","","","","","","","Furuya A., Fujisaki J., Uehara Y., Shimizu K., Oshima H., Murakami Y., Takahashi N., Iron loss analysis of the electrical steel sheet under the high frequency excitation, The Papers of Joint Technical Meeting on Magnetics IEEJ, SA-13-6RM-13-6, (2013); Tanaka H., Nakamura K., Ichinokura O., IEEJ Trans. FM, 134, 4, pp. 243-249, (2014); Tanaka H., Nakamura K., Ichinokura O., Calculation of Iron Loss in Soft Ferromagnetic Materials using Magnetic Circuit Model Taking Magnetic Hysteresis into Consideration, Journal of the Magnetics Society of Japan, 39, 2, pp. 65-70, (2015); Tanaka H., Nakamura K., Ichinokura O., Dynamic analysis of amorphous transformer in switching power converters based on magnetic circuit method with llg equation, MMM-Intermag 2016, FJ-08, (2016); Bobbio S., Miano G., Serpico C., Visone C., Models of magnetic hysteresis based on play and stop hysteresis, IEEE Trans. Magn., 33, 6, pp. 4417-4426, (1997); Tanaka H., Nakamura K., Ichinokura O., The papers of joint technical meeting on, Magnetics IEEJ, MAG-16-141, (2016); Nakamura K., Ichinokura O., Reluctance network based dynamic analysis in power magnetics, IEEJ Trans. FM, 128, 8, pp. 506-510, (2008)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Industry Applications Society (IAS); IEEE Power Electronics Society (PELS); IEEJ Industry Applications Society (IAS)","8th International Power Electronics Conference, IPEC-Niigata - ECCE Asia 2018","20 May 2018 through 24 May 2018","Niigata","141466","","978-488686405-5","","","English","Int. Power Electron. Conf., IPEC-Niigata - ECCE Asia","Conference paper","Final","","Scopus","2-s2.0-85057308660" +"Lim H.; Lee S.; Shin H.","Lim, Hyein (55201246400); Lee, Seungjun (36064894500); Shin, Hyungsoon (7404012125)","55201246400; 36064894500; 7404012125","A Survey on the Modeling of Magnetic Tunnel Junctions for Circuit Simulation","2016","Active and Passive Electronic Components","2016","","3858621","","","","11","10.1155/2016/3858621","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84973161166&doi=10.1155%2f2016%2f3858621&partnerID=40&md5=d8ffca842b52832692ce2cac6f655e7c","Department of Electronics Engineering, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul, 120-750, South Korea","Lim H., Department of Electronics Engineering, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul, 120-750, South Korea; Lee S., Department of Electronics Engineering, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul, 120-750, South Korea; Shin H., Department of Electronics Engineering, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemoon-Gu, Seoul, 120-750, South Korea","Spin-transfer torque-based magnetoresistive random access memory (STT-MRAM) is a promising candidate for universal memory that may replace traditional memory forms. It is expected to provide high-speed operation, scalability, low-power dissipation, and high endurance. MRAM switching technology has evolved from the field-induced magnetic switching (FIMS) technique to the spin-transfer torque (STT) switching technique. Additionally, material technology that induces perpendicular magnetic anisotropy (PMA) facilitates low-power operation through the reduction of the switching current density. In this paper, the modeling of magnetic tunnel junctions (MTJs) is reviewed. Modeling methods and models of MTJ characteristics are classified into two groups, macromodels and behavioral models, and the most important characteristics of MTJs, the voltage-dependent MTJ resistance and the switching behavior, are compared. To represent the voltage dependency of MTJ resistance, some models are based on physical mechanisms, such as Landau-Lifshitz-Gilbert (LLG) equation or voltage-dependent conductance. Some behavioral models are constructed by adding fitting parameters or introducing new physical parameters to represent the complex switching behavior of an MTJ over a wide range of input current conditions. Other models that are not based on physical mechanisms are implemented by simply fitting to experimental data. © 2016 Hyein Lim et al.","","Behavioral research; Circuit simulation; Magnetic anisotropy; Magnetic circuits; Magnetic recording; Magnetic storage; Magnetism; Random access storage; Switching; Timing circuits; Tunnel junctions; Landau-Lifshitz-Gilbert equations; Low-power dissipation; Magnetic tunnel junction; Material technologies; Perpendicular magnetic anisotropy; Spin transfer torque; Switching current density; Voltage-dependent conductance; MRAM devices","","","","","","","Ikeda S., Hayakawa J., Lee Y.M., Et al., Magnetic tunnel junctions for spintronic memories and beyond, IEEE Transactions on Electron Devices, 54, 5, pp. 991-1002, (2007); Huai Y., Apalkov D., Diao Z., Et al., Structure, materials and shape optimization of magnetic tunnel junction devices: Spintransfer switching current reduction for future magnetoresistive random access memory application, Japanese Journal of Applied Physics, 45, 5, pp. 3835-3841, (2006); Jabeur K., Bernard-Granger F., Di Pendina G., Prenat G., Dieny B., Comparison of Verilog-A compactmodelling strategies for spintronic devices, Electronics Letters, 50, 19, pp. 1353-1355, (2014); Vatankhahghadim A., Huda S., Sheikholeslami A., A survey on circuit modeling of spin-transfer-torque magnetic tunnel junctions, IEEE Transactions on Circuits and Systems I: Regular Papers, 61, 9, pp. 2634-2643, (2014); Prenat G., El Baraji M., Guo W., Et al., CMOS/magnetic hybrid architectures, Proceedings of the 14th IEEE International Conference on Electronics, Circuits and Systems (ICECS '07), pp. 190-193, (2007); Rowlands G.E., Rahman T., Katine J.A., Et al., Deep subnanosecond spin torque switching inmagnetic tunnel junctions with combined in-plane and perpendicular polarizers, Applied Physics Letters, 98, 10, (2011); Worledge D.C., Hu G., Abraham D.W., Et al., Spin torque switching of perpendicular TaCoFeBMgO-based magnetic tunnel junctions, Applied Physics Letters, 98, (2011); Zhao W., Belhaire E., Mistral Q., Et al., Macro-model of spintransfer torque based magnetic tunnel junction device for hybrid magnetic-CMOS design, Proceedings of the IEEE International Behavioral Modeling and Simulation Workshop (BMAS '06), pp. 40-43, (2006); Madec M., Kammerer J.-B., Hebrard L., Compact modeling of a magnetic tunnel junction-part II: Tunneling current model, IEEE Transactions on Electron Devices, 57, 6, pp. 1416-1424, (2010); Panagopoulos G.D., Augustine C., Roy K., Physicsbased SPICE-compatible compact model for simulating hybrid MTJ/CMOS circuits, IEEE Transactions on Electron Devices, 60, 9, pp. 2808-2814, (2013); Mukherjee S.S., Kurinec S.K., A stable SPICE macromodel for magnetic tunnel junctions for applications in memory and logic circuits, IEEE Transactions on Magnetics, 45, 9, pp. 3260-3268, (2009); Lee S., Lee H., Kim S., Lee S., Shin H., A novel macro-model for spin-transfer-torque based magnetic-tunneljunction elements, Solid-State Electronics, 54, 4, pp. 497-503, (2010); Diao Z., Li Z., Wang S., Et al., Spin-transfer torque switching in magnetic tunnel junctions and spin-transfer torque random access memory, Journal of Physics Condensed Matter, 19, 16, (2007); Raychowdhury A., Somasekhar D., Karnik T., De V., Design space and scalability exploration of 1T-1STT MTJ memory arrays in the presence of variability and disturbances, Proceedings of the IEEE International Electron Devices Meeting. Technical Digest (IEDM '09), (2009); Harms J.D., Ebrahimi F., Yao X., Wang J.-P., SPICE macromodel of spin-torque-transfer-operated magnetic tunnel junctions, IEEE Transactions on Electron Devices, 57, 6, pp. 1425-1430, (2010); Lim H., Lee S., Shin H., Unified analytical model for switching behavior of magnetic tunnel junction, IEEE Electron Device Letters, 35, 2, pp. 193-195, (2014); Xu Z., Yang C., Mao M., Sutaria K.B., Chakrabarti C., Cao Y., Compact modeling of STT-MTJ devices, Solid-State Electronics, 102, pp. 76-81, (2014); Kim S., Lee S., Shin H., Advanced macro-model with pulse-width dependent switching characteristic for spin transfer torque based magnetic-tunnel-junction elements, Japanese Journal of Applied Physics, 49, 4, (2010); Durlam M., Addie D., Akerman J., Et al., A 0.18 μm 4Mb Toggling MRAM, (2003); Prejbeanu I.L., Kerekes M., Sousa R.C., Et al., Thermally assisted MRAM, Journal of Physics Condensed Matter, 19, 16, (2007); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Physical Review B, 62, (2000); Sato H., Yamanouchi M., Miura K., Et al., Junction size effect on switching current and thermal stability in CoFeB/MgO perpendicular magnetic tunnel junctions, Applied Physics Letters, 99, 4, (2011); Park J.H., Kim Y., Lim W.C., Et al., Enhancement of data retention and write current scaling for sub-20 nm STT-MRAM by utilizing dual interfaces for perpendicular magnetic anisotropy, Proceedings of the Symposium on VLSI Technology (VLSIT '12), pp. 57-58, (2012); Kishi T., Yoda H., Kai T., Et al., Lower-current and fast switching of A perpendicular TMR for high speed and high density spin-transfer-torque MRAM, Proceedings of the IEEE International Electron Devices Meeting (IEDM'08), pp. 1-4, (2008); Amiri P.K., Zeng Z.M., Langer J., Et al., Switching current reduction using perpendicular anisotropy in CoFeB-MgO magnetic tunnel junctions, Applied Physics Letters, 98, 11, (2011); Zhao H., Glass B., Amiri P.K., Et al., Sub-200 ps spin transfer torque switching in in-plane magnetic tunnel junctions with interface perpendicular anisotropy, Journal of Physics D: Applied Physics, 45, 2, (2012); Nishimura N., Hirai T., Koganei A., Et al., Magnetic tunnel junction device with perpendicular magnetization films for high-density magnetic random access memory, Journal of Applied Physics, 91, 8, pp. 5246-5249, (2002); Ohmori H., Hatori T., Nakagawa S., Perpendicular magnetic tunnel junction with tunneling magnetoresistance ratio of 64% using MgO (100) barrier layer prepared at room temperature, Journal of Applied Physics, 103, 7, (2008); Liu H., Bedau D., Backes D., Katine J.A., Langer J., Kent A.D., Ultrafast switching in magnetic tunnel junction based orthogonal spin transfer devices, Applied Physics Letters, 97, 24, (2010); Ikeda S., Miura K., Yamamoto H., Et al., A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction, Nature Materials, 9, 9, pp. 721-724, (2010); Slonczewski J.C., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, 1-2, pp. L1-L7, (1996); Slonczewski J.C., Currents, torques, and polarization factors in magnetic tunnel junctions, Physical Review B, 71, 2, (2005); 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Chen Y., Wang X., Li H., Xi H., Yan Y., Zhu W., Design margin exploration of spin-transfer torque RAM (STT-RAM) in scaled technologies, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 18, 12, pp. 1724-1734, (2010); Sakimura N., Nebashi R., Tsuji Y., Et al., High-speed simulator including accurate MTJ models for spintronics integrated circuit design, Proceedings of the IEEE International Symposium on Circuits and Systems, pp. 1971-1974, (2012); Manipatruni S., Nikonov D.E., Young I.A., Vector spin modeling formagnetic tunnel junctions with voltage dependent effects, Journal of Applied Physics, 115, 17, (2014); Li Z., Zhang S., Thermally assisted magnetization reversal in the presence of a spin-transfer torque, Physical Review B, 69, (2004); Koch R.H., Katine J.A., Sun J.Z., Time-resolved reversal of spin-transfer switching in a nanomagnet, Physical Review Letters, 92, 8, (2004); Lim H., Lee S., Shin H., Advanced circuit-level model for temperature-sensitive read/write operation of a magnetic tunnel junction, IEEE Transactions on Electron Devices, 62, 2, pp. 666-672, (2015); Shang Y., Fei W., Yu H., Analysis and modeling of internal state variables for dynamic effects of nonvolatile memory devices, IEEE Transactions on Circuits and Systems. I. Regular Papers, 59, 9, pp. 1906-1918, (2012)","S. Lee; Department of Electronics Engineering, Ewha Womans University, Seodaemoon-Gu, Seoul, 11-1 Daehyun-Dong, 120-750, South Korea; email: slee@ewha.ac.kr","","Hindawi Limited","","","","","","08827516","","APECE","","English","Act Passive Electron Compon","Review","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-84973161166" +"Chotorlishvili L.; Toklikishvili Z.; Etesami S.R.; Dugaev V.K.; Barnas̈ J.; Berakdar J.","Chotorlishvili, L. (6602824544); Toklikishvili, Z. (6504730528); Etesami, S.R. (56275739300); Dugaev, V.K. (7006169807); Barnas̈, J. (35473909700); Berakdar, J. (7005673654)","6602824544; 6504730528; 56275739300; 7006169807; 35473909700; 7005673654","Magnon-driven longitudinal spin Seebeck effect in FIN and NIFIN structures: Role of asymmetric in-plane magnetic anisotropy","2015","Journal of Magnetism and Magnetic Materials","396","","","254","262","8","11","10.1016/j.jmmm.2015.08.059","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84940474262&doi=10.1016%2fj.jmmm.2015.08.059&partnerID=40&md5=f8f726c6e9531e9132d2f5be98f418ae","Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, 06099, Germany; Department of Physics, Tbilisi State University, Chavchavadze av. 3, Tbilisi, 0128, Georgia; Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, Halle, 06120, Germany; Department of Physics, Rzeszów University of Technology, al. Powstanców Warszawy 6, Rzeszów, 35-959, Poland; Departamento de Física and CFIF, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisbon, 1049-001, Portugal; Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, Poznań, 61-614, Poland; Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, Poznań, 60-179, Poland","Chotorlishvili L., Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, 06099, Germany; Toklikishvili Z., Department of Physics, Tbilisi State University, Chavchavadze av. 3, Tbilisi, 0128, Georgia; Etesami S.R., Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, 06099, Germany, Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, Halle, 06120, Germany; Dugaev V.K., Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, 06099, Germany, Department of Physics, Rzeszów University of Technology, al. Powstanców Warszawy 6, Rzeszów, 35-959, Poland, Departamento de Física and CFIF, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisbon, 1049-001, Portugal; Barnas̈ J., Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, Poznań, 61-614, Poland, Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, Poznań, 60-179, Poland; Berakdar J., Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Halle, 06099, Germany","The influence of an asymmetric in-plane magnetic anisotropy KxaKy on the thermally activated spin current is studied theoretically for two different systems: (i) the F|N system consisting of a ferromagnetic insulator (F) in a direct contact with a nonmagnetic metal (N) and (ii) the sandwich structure N|F|N consisting of a ferromagnetic insulating part sandwiched between two nonmagnetic metals. It is shown that when the difference between the temperatures of the two nonmagnetic metals in a N|F|N structure is not large, the spin pumping currents from the magnetic part to the nonmagnetic ones are equal in amplitude and have opposite directions, so only the spin torque current contributes to the total spin current. The spin current flows then from the nonmagnetic metal with the higher temperature to the nonmagnetic metal having a lower temperature. Its amplitude varies linearly with the difference in temperatures. In addition, we have found that if the magnetic anisotropy is in the layer plane, then the spin current increases with the magnon temperature, while in the case of an out-of-plane magnetic anisotropy the spin current decreases when the magnon temperature enhances. Enlarging the difference between the temperatures of the nonmagnetic metals, the linear response becomes important, as confirmed by analytical expressions inferred from the Fokker-Planck approach and by the results obtained upon a full numerical integration of the stochastic Landau-Lifshitz-Gilbert equation. © 2015 Elsevier B.V.All rights reserved.","Fokker-Planck approach; Magnonic spin Seebeck; Stochastic Landau-Lifshitz-Gilbert (LLG) equation","Anisotropy; Ferromagnetic materials; Ferromagnetism; Fokker Planck equation; Magnetism; Metals; Numerical methods; Spin waves; Stochastic systems; Analytical expressions; Ferromagnetic insulating; Ferromagnetic insulator; Fokker-Planck approach; In-plane magnetic anisotropy; Landau-Lifshitz-Gilbert equations; Out-of-plane magnetic anisotropy; Seebeck; Magnetic anisotropy","","","","","National Science Center in Poland, (DEC-2012/04/A/ST3/00372); Deutsche Forschungsgemeinschaft, DFG, (SFB762)","This work has been partly supported by the National Science Center in Poland by the Grant DEC-2012/04/A/ST3/00372 (V.K.D. and J.B.) and the DFG through SFB762 . 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Lett., 111, (2013); Schmid M., Srichandan S., Meier D., Kuschel T., Schmalhorst J.-M., Vogel M., Reiss G., Strunk C., Back C.H., Phys. Rev. Lett., 111, (2013); Kloeden P.E., Numerical Solution of SDE Through Computer Experiments, (1994); Sukhov A., Berakdar J., Phys. Rev. B, 79, (2009); Sukhov A., Berakdar J., Phys. Rev. Lett., 102, (2009); Chotorlishvili L., Toklikishvili Z., Sukhov A., Horley P.P., Dugaev V.K., Vieira V.R., Trimper S., Berakdar J., J. Appl. Phys., 114, (2013); Joyeux X., Devolder T., Kim J.-V., Gomez De La Torre Y., Eimer S., Chappert C., J. Appl. Phys., 110, (2011); Brataas A., Kent A.D., Ohno H., Nat. Mater., 11, (2012)","","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84940474262" +"Wysin G.M.","Wysin, G.M. (6701324945)","6701324945","Vortex dynamics in thin elliptic ferromagnetic nanodisks","2015","Low Temperature Physics","41","10","","788","800","12","2","10.1063/1.4932353","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84946542713&doi=10.1063%2f1.4932353&partnerID=40&md5=3df68dfbbf5ba96eb3203525e09527ca","Department of Physics, Kansas State University, Manhattan, 66506-2601, KS, United States","Wysin G.M., Department of Physics, Kansas State University, Manhattan, 66506-2601, KS, United States","Vortex gyrotropic motion in thin ferromagnetic nanodisks of elliptical shape is described here for a pure vortex state and for a situation with thermal fluctuations. The system is analyzed using numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equations, including the demagnetization field calculated with a Green's function approach for thin film problems. At finite temperature the thermalized dynamics is found using a second order Heun algorithm for a magnetic Langevin equation based on the LLG equations. The vortex state is stable only within a limited range of ellipticity, outside of which a quasi-single-domain becomes the preferred minimum energy state. A vortex is found to move in an elliptical potential, whose force constants along the principal axes are determined numerically. The eccentricity of vortex motion is directly related to the force constants. Elliptical vortex motion is produced spontaneously by thermal fluctuations. The vortex position and velocity distributions in thermal equilibrium are Boltzmann distributions. The results show that vortex motion in elliptical disks can be described by a Thiele equation. © 2015 AIP Publishing LLC.","","Aerodynamics; Boltzmann equation; Differential equations; Ferromagnetic materials; Ferromagnetism; Boltzmann distribution; Demagnetization fields; Finite temperatures; Green's function approaches; Landau-Lifshitz-Gilbert equations; Langevin equation; Thermal equilibriums; Thermal fluctuations; Vortex flow","","","","","","","Usov N.E., Peschany S.A., J. Magn. Magn. Mater, 118, (1993); Raabe J., Pulwey R., Sattler S., Schweinbock T., Zweck J., Weiss D., J. Appl. Phys, 88, (2000); Kasai S., Nakatani Y., Kobayashi K., Kohno H., Ono T., Phys. Rev. Lett, 97, (2006); Pribiag V.S., Krivorotov I.N., Fuchs G.D., Braganca P.M., Ozatay O., Sankey C., Ralph D.C., Buhrman R.A., Nat. Phys, 3, (2007); Guslienko K.Y., Lee K.-S., Kim S.-K., Phys. Rev. Lett, 100, (2008); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. 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Lett, 78, (2001); Ivanov B.A., Zaspel C.E., Appl. Phys. Lett, 95, (2004); Garcia-Cervera C.J., Magnetic domains and magnetic domain walls; Garcia-Cervera C.J., Gimbutas Z., Weinan J.E., J. Comput. Phys., E184, (2003); Machado T.S., T. G. Rappoport, and L. C. Sampaio, Appl. Phys. Lett, 100, (2012); Gioia G., James R.D., Proc. R. Soc. London, Ser. A, 453, (1997); Huang Z., J. Comp. Math., 21, 1, (2003); Suessa D., Fidler J., Schrefl T., Handb. Magn. Mater, 16, (2006); Sasaki J., Matsubara F., J. Phys. Soc. Jpn, 66, (1997); Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, (1935); de Leeuw F.H., van den Poel R., Enz U., Rep. Prog. Phys, 43, (1980); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev., B, 58, (1998); Nowak U., Annual Reviews of Computational Physics IX, (2000); Marsaglia G., Zaman A., Comput. Phys, 8, 1, (1994); Wysin G.M., Phys. Rev., B, 54, (1996); Ivanov B.A., Galkina E.G., Galkin A.Y., Fiz. Nizk. Temp, 36, (2010); Zaspel C.E., Wysin G.M., Phys. Rev. B, 90, (2014)","G.M. Wysin; Department of Physics, Kansas State University, Manhattan, 66506-2601, United States; email: wysin@phys.ksu.edu","","American Institute of Physics Inc.","","","","","","1063777X","","","","English","Low Temp. Phys","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84946542713" +"Denisov S.I.; Lyutyy T.V.; Pedchenko B.O.; Hryshko O.M.","Denisov, S.I. (7103114636); Lyutyy, T.V. (6506392457); Pedchenko, B.O. (56226430600); Hryshko, O.M. (57190220305)","7103114636; 6506392457; 56226430600; 57190220305","Induced magnetization and power loss for a periodically driven system of ferromagnetic nanoparticles with randomly oriented easy axes","2016","Physical Review B","94","2","024406","","","","13","10.1103/PhysRevB.94.024406","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84978419948&doi=10.1103%2fPhysRevB.94.024406&partnerID=40&md5=a355f14173edc42a5c31cd4f8c0a2f02","Sumy State University, 2 Rimsky-Korsakov Street, Sumy, UA-40007, Ukraine","Denisov S.I., Sumy State University, 2 Rimsky-Korsakov Street, Sumy, UA-40007, Ukraine; Lyutyy T.V., Sumy State University, 2 Rimsky-Korsakov Street, Sumy, UA-40007, Ukraine; Pedchenko B.O., Sumy State University, 2 Rimsky-Korsakov Street, Sumy, UA-40007, Ukraine; Hryshko O.M., Sumy State University, 2 Rimsky-Korsakov Street, Sumy, UA-40007, Ukraine","We study the effect of an elliptically polarized magnetic field on a system of noninteracting, single-domain ferromagnetic nanoparticles characterized by a uniform distribution of easy axis directions. Our main goal is to determine the average magnetization of this system and the power loss in it. In order to calculate these quantities analytically, we develop a general perturbation theory for the Landau-Lifshitz-Gilbert (LLG) equation and find its steady-state solution for small magnetic field amplitudes. On this basis, we derive the second-order expressions for the average magnetization and power loss, investigate their dependence on the magnetic field frequency, and analyze the role of subharmonic resonances resulting from the nonlinear nature of the LLG equation. For arbitrary amplitudes, the frequency dependence of these quantities is obtained from the numerical solution of this equation. The impact of transitions between different regimes of regular and chaotic dynamics of magnetization, which can be induced in nanoparticles by changing the magnetic field frequency, is examined in detail. © 2016 American Physical Society.","","","","","","","Ministry of Education and Science of Ukraine, MESU, (0116U002622)","The authors are grateful to the Ministry of Education and Science of Ukraine for financial support under Grant No. 0116U002622.","Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Switching behavior of a Stoner particle beyond the relaxation time limit, Phys. Rev. B, 61, (2000); Gerrits Th., Van Den Berg H.A.M., Hohlfeld J., Bar L., Rasing Th., Ultrafast precessional magnetization reversal by picosecond magnetic field pulse shaping, Nature (London), 418, (2002); Kaka S., Russek S.E., Precessional switching of submicrometer spin valves, Appl. Phys. Lett., 80, (2002); Serpico C., Mayergoyz I.D., Bertotti G., Analytical solutions of Landau-Lifshitz equation for precessional switching, J. Appl. Phys., 93, (2003); Sun Z.Z., Wang X.R., Fast magnetization switching of Stoner particles: A nonlinear dynamics picture, Phys. Rev. B, 71, (2005); Thirion C., Wernsdorfer W., Mailly D., Switching of magnetization by nonlinear resonance studied in single nanoparticles, Nat. Mater., 2, (2003); Sun Z.Z., Wang X.R., Magnetization reversal through synchronization with a microwave, Phys. Rev. B, 74, (2006); Woltersdorf G., Back C.H., Microwave Assisted Switching of Single Domain (Equation presented) Elements, Phys. Rev. Lett., 99, (2007); Zhu J.-G., Zhu X., Tang Y., Microwave assisted magnetic recording, IEEE Trans. Magn., 44, (2008); Bertotti G., Mayergoyz I.D., Serpico C., D'Aquino M., Bonin R., Nonlinear-dynamical-system approach to microwave-assisted magnetization dynamics (invited), J. Appl. 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E, 86, (2012); Racz J., De Chatel P.F., Szabo I.A., Szunyogh L., Nandori I., Improved efficiency of heat generation in nonlinear dynamics of magnetic nanoparticles, Phys. Rev. E, 93, (2016); Lyutyy T.V., Denisov S.I., Peletskyi A.Yu., Binns C., Energy dissipation in single-domain ferromagnetic nanoparticles: Dynamical approach, Phys. Rev. B, 91, (2015); Denisov S.I., Lyutyy T.V., Hanggi P., Magnetization of Nanoparticle Systems in a Rotating Magnetic Field, Phys. Rev. Lett., 97, (2006); Denisov S.I., Polyakov A.Yu., Lyutyy T.V., Resonant suppression of thermal stability of the nanoparticle magnetization by a rotating magnetic field, Phys. Rev. B, 84, (2011); Stoner E.C., Wohlfarth E.P., A mechanism of hysteresis in heterogeneous alloys, Philos. Trans. R. Soc. London A, 240, (1948); Guimaraes A.P., Principles of Nanomagnetism, (2009); Brown W.F., Thermal fluctuations in a single-domain particle, Phys. Rev., 130, (1963); Coffey W.T., Kalmykov Yu.P., Waldron J.T., The Langevin Equation, (2004); Martinez E., Lopez-Diaz L., Torres L., Nonphenomenological damping constant due to eddy current losses in uniformly magnetized samples, J. Appl. Phys., 99, (2006); Denisov S.I., Lyutyy T.V., Pedchenko B.O., Babych H.V., Eddy current effects in the magnetization dynamics of ferromagnetic metal nanoparticles, J. Appl. Phys., 116, (2014); Frey N.A., Peng S., Cheng K., Sun S., Magnetic nanoparticles: Synthesis, functionalization, and applications in bioimaging and magnetic energy storage, Chem. Soc. Rev., 38, (2009); Sun S., Advanced Magnetic Nanostructures, pp. 239-260, (2006); Toulemon D., Pichon B.P., Cattoen X., Man M.W.C., Begin-Colin S., 2D assembly of non-interacting magnetic iron oxide nanoparticles via ""click"" chemistry, Chem. Commun., 47, (2011)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84978419948" +"Toga Y.; Nishino M.; Miyashita S.; Miyake T.; Sakuma A.","Toga, Yuta (26532037600); Nishino, Masamichi (7103009415); Miyashita, Seiji (7102333760); Miyake, Takashi (7202951411); Sakuma, Akimasa (7102719646)","26532037600; 7103009415; 7102333760; 7202951411; 7102719646","Anisotropy of exchange stiffness based on atomic-scale magnetic properties in the rare-earth permanent magnet Nd2Fe14 B","2018","Physical Review B","98","5","054418","","","","42","10.1103/PhysRevB.98.054418","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85051768681&doi=10.1103%2fPhysRevB.98.054418&partnerID=40&md5=ce86152f5ae9357f9ca710ac827993ae","ESICMM, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan; Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan; Department of Physics, University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan; CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan; Department of Applied Physics, Tohoku University, Sendai, Miyagi, 980-8579, Japan","Toga Y., ESICMM, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan; Nishino M., ESICMM, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan, Research Center for Advanced Measurement and Characterization, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan; Miyashita S., ESICMM, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan, Department of Physics, University of Tokyo, Bunkyo-Ku, Tokyo, 113-0033, Japan; Miyake T., ESICMM, National Institute for Materials Science (NIMS), Tsukuba, Ibaraki, 305-0047, Japan, CD-FMat, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan; Sakuma A., Department of Applied Physics, Tohoku University, Sendai, Miyagi, 980-8579, Japan","We examine the anisotropic properties of the exchange stiffness constant A for a rare-earth permanent magnet, Nd2Fe14B, by connecting analyses with two different scales of length, i.e., Monte Carlo (MC) method with an atomistic spin model and Landau-Lifshitz-Gilbert (LLG) equation with a continuous magnetic model. The atomistic MC simulations are performed on the spin model of Nd2Fe14B constructed from ab initio calculations, and the LLG micromagnetics simulations are performed with the parameters obtained by the MC simulations. We clarify that the amplitude and the thermal property of A depend on the orientation in the crystal, which are attributed to the layered structure of Nd atoms and weak exchange couplings between Nd and Fe atoms. We also confirm that the anisotropy of A significantly affects the threshold field for the magnetization reversal (coercivity) given by the depinning process. © 2018 American Physical Society.","","","","","","","Elements Strategy Initiative Center for Magnetic Materials; Japan Society for the Promotion of Science, JSPS, (17K05508); Ministry of Education, Culture, Sports, Science and Technology, Monbusho","We acknowledge collaboration and fruitful discussions with Taro Fukazawa, Taichi Hinokihara, Shotaro Doi, Munehisa Matsumoto, Hisazumi Akai, and Satoshi Hirosawa. This work was partly supported by Elements Strategy Initiative Center for Magnetic Materials (ESICMM) under the auspices of MEXT; by MEXT as a social and scientific priority issue (Creation of New Functional Devices and High-Performance Materials to Support Next-Generation Industries; CDMSI) to be tackled by using a post-K computer. The computation was performed on Numerical Materials Simulator at NIMS; the facilities of the Supercomputer Center, the Institute for Solid State Physics, the University of Tokyo; the supercomputer of ACCMS, Kyoto University.","Buschow K.H.J., Rep. Prog. Phys., 40, (1977); Miyake T., Akai H., J. Phys. Soc. Jpn., 87, (2018); Sagawa M., Fujimura S., Yamamoto H., Matsuura Y., Hiraga K., IEEE Trans. Magn., 20, (1984); Croat J.J., Herbst J.F., Lee R.W., Pinkerton F.E., J. Appl. Phys., 55, (1984); Herbst J.F., Croat J.J., Pinkerton F.E., Yelon W.B., Phys. Rev. B, 29, (1984); Hirosawa S., Nishino M., Miyashita S., Adv. Nat. Sci: Nanosci. Nanotechnol., 8, (2017); Givord D., Rossignol M., Barthem V.M.T.S., J. Magn. Magn. Mater., 258-259, (2003); Fischbacher J., Kovacs A., Gusenbauer M., Oezelt H., Exl L., Bance S., Schrefl T., J. Phys. D: Appl. Phys., 51, (2018); Paul D.I., J. Appl. Phys., 53, (1982); Sakuma A., Tanigawa S., Tokunaga M., J. Magn. Magn. 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Phys., 35, (1996); Li W., Zhao L.Z., Zhou Q., Zhong X.C., Liu Z.W., Comput. Mater. Sci., 148, (2018); Kneller E.F., Hawig R., IEEE Trans. Magn., 27, (1991); Skomski R., Coey J.M.D., Phys. Rev. B, 48, (1993); Sasaki T.T., Ohkubo T., Hono K., Acta Mater., 115, (2016); Moriya H., Tsuchiura H., Sakuma A., J. Appl. Phys., 105, (2009); Toga Y., Suzuki T., Sakuma A., J. Appl. Phys., 117, (2015); Tatetsu Y., Tsuneyuki S., Gohda Y., Phys. Rev. Applied, 6, (2016); Sabiryanov R.F., Jaswal S.S., Phys. Rev. B, 58, (1998); Toga Y., Moriya H., Tsuchiura H., Sakuma A., J. Phys.: Conf. Ser., 266, (2011); Ogawa D., Koike K., Mizukami S., Miyazaki T., Oogane M., Ando Y., Kato H., Appl. Phys. Lett., 107, (2015); Umetsu N., Sakuma A., Toga Y., Phys. Rev. B, 93, (2016); Da Silva Junior A.F., De Campo M.F., Martins A.S., J. Magn. Magn. Mater., 442, (2017)","","","American Physical Society","","","","","","24699950","","","","English","Phys. Rev. B","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-85051768681" +"Yetiş H.; Denizli H.","Yetiş, Hakan (6507725661); Denizli, Haluk (35227195400)","6507725661; 35227195400","Antidot shape dependence of switching mechanism in permalloy samples","2017","Journal of Magnetism and Magnetic Materials","422","","","181","187","6","3","10.1016/j.jmmm.2016.08.076","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84984919501&doi=10.1016%2fj.jmmm.2016.08.076&partnerID=40&md5=2d638c8ab9118f9bb46e2248760eaaf8","Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey","Yetiş H., Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey; Denizli H., Abant Izzet Baysal University, Physics Department, Gölköy Campus, Bolu, 14280, Turkey","We study antidot shape dependence of the switching magnetization for various permalloy samples with square and triangular arrays of nanometer scale antidots. The remnant magnetization, squareness ratio, and coercive fields of the samples are extracted from the hysteresis loops which are obtained by solving the Landau-Lifshitz-Gilbert (LLG) equation numerically. We find several different magnetic spin configurations which reveal the existence of superdomain wall structures. Our results are discussed in terms of the local shape anisotropy, array geometry, and symmetry properties in order to explain the formation of inhomogeneous domain structures. © 2016 Elsevier B.V.","Antidots; Coercivity; Micromagnetic simulation; OOMMF; Permalloy","Coercive force; Magnetic materials; Magnetization; Antidots; Landau-Lifshitz-Gilbert equations; Micromagnetic simulations; OOMMF; Permalloy; Remnant magnetization; Switching mechanism; Symmetry properties; Nickel alloys","","","","","Abant Izzet Baysal Üniversitesi, AIBÜ; Scientific Research Plan Projects of Shaanxi Education Department, (2015.03.02.815)","This work was supported by the Abant Izzet Baysal University , Department of Scientific Research Projects under the contract 2015.03.02.815 .","Kim S.-K., Micromagnetic computer simulations of spin waves in nanometer-scale patterned magnetic elements, J. Phys. D: Appl. Phys., 43, (2010); Tse D.H.Y., Steinmuller S.J., Trypiniotis T., Anderson D., Jones G.A.C., Bland J.A.C., Barnes C.H.W., Static and dynamic magnetic properties of Ni80Fe20 square antidot arrays, Phys. Rev. B, 79, pp. 054426-054429, (2009); Kruglyak V.V., Demokritov S.O., Grundler D., Magnonics, J. Phys. D: Appl. Phys., 43, pp. 264001-264014, (2010); Heyderman L.J., Nolting F., Backes D., Czekaj S., Lopez-Diaz L., Klaui M., Rudiger U., Vaz C.A.F., Bland J.A.C., Matelon R.J., Volkmann U.G., Fischer P., Magnetization reversal in cobalt antidot arrays, Phys. Rev. B, 73, (2006); Krawczyk M., Grundler D., Review and prospects of magnonic crystals and devices with reprogrammable band structure, J. Phys.: Condens. Matter, 26, pp. 123202-123232, (2014); Van de Wiele B., Manzin A., Vansteenkiste A., Bottauscio O., Dupre L., De Zutter D., A micromagnetic study of the reversal mechanism in permalloy antidot arrays, J. Appl. Phys., 111, pp. 053915-053919, (2012); Jaafar M., Navas D., Asenjo A., Vazquez M., Hernandez-Velez M., Garcia-Martin J.M., Magnetic domain structure of nanohole arrays in Ni films, J. Appl. Phys., 101, (2007); Hu X.K., Sievers S., Muller A., Janke V., Schumacher H.W., Classification of super domains and super domain walls in permalloy antidot lattices, Phys. Rev. B, 84, pp. 024404-024406, (2011); Rodriguez L.A., Magen C., Snoeck E., Gatel C., Castan-Guerrero C., Sese1 J., Garcia L.M., Herrero-Albillos J., Bartolome J., Bartolome F., Ibarra M.R., Nanotechnology, 25, pp. 385703-385716, (2014); Wang C.C., Adeyeye A.O., Singh N., Magnetic antidot nanostructures: effect of lattice geometry, Nanotechnology, 17, pp. 1629-1636, (2006); Tanakaa M., Itoha K., Iwamotoa H., Yamaguchia A., Miyajimaa H., Yamaokab T., Magnetic properties of nanometer-scale FeNi antidot array system, J. Magn. Magn. Mater., 310, pp. e792-e793, (2007); Paz E., Cebollada F., Palomares F.J., Gonzalez J.M., Im M.-Y., Fischer P., Scaling of the coercivity with the geometrical parameters in epitaxial Fe antidot arrays, J. Appl. Phys., 111, (2012); Krivoruchko V.N., Marchenko A.I., Apparent sixfold configurational anisotropy and spatial confinement of ferromagnetic resonances in hexagonal magnetic antidot lattices, J. Appl. Phys., 109, (2011); Mallick S., Bedanta S., Size and shape dependence study of magnetization reversal in magnetic antidot lattice arrays, J. Magn. Magn. Mater., 382, pp. 158-164, (2015); Neusser S., Botters B., Grundler D., Localization, confinement, and field-controlled propagation of spin waves in Ni80Fe20 antidot lattices, Phys. Rev. B, 78, pp. 054406-054410, (2008); Mandal R., Laha P., Das K., Saha S., Barman S., Raychaudhuri A.K., Barmana A., Effects of antidot shape on the spin wave spectra of two-dimensional Ni80Fe20 antidot lattices, Appl. Phys. Lett., 103, pp. 262410-262414, (2013); Kumar D., Sabareesan P., Wang W., Fangohr H., Barman A., Effect of hole shape on spin-wave band structure in one-dimensional magnonic antidot waveguide, J. Appl. Phys., 114, pp. 023910-023918, (2013); Gulyaev Y.V., Nikitov S.A., Zhivotovski L.V., Klimov A.A., Tailhades P., Presmanes L., Bonningue C., Tsai, 4 C.S., Vysotski S.L., Filimonov Y.A., Ferromagnetic films with magnon bandgap periodic structures: magnon crystals, JETP Lett., 77, pp. 0567-0570, (2003); Grafe J., Haering F., Tietze T., Audehm P., Weigand M., Wiedwald U., Ziemann P., Gawronski P., Schutz G., Goering E.J., Perpendicular magnetization from in-plane fields in nano-scaled antidot lattices, Nanotechnology, 26, pp. 225203-225206, (2015); de Araujo C.I.L., Silva R.C., Ribeiro I.R.B., Nascimento F.S., Felix J.F., Ferreira S.O., Mol L.A.S., Moura-Melo W.A., Pereira A.R., Magnetic vortex crystal formation in the antidot complement of square artificial spin ice, Appl. Phys. Lett., 104, pp. 092402-092404, (2014); Yetis H., Denizli H., Antidot effects on micromagnetic behavior of Py ferromagnetic samples, J. Magn. Magn. Mater., 413, pp. 14-18, (2016); Abo G.S., Hong Y.-K., Park J., Lee J., Lee W., Choi B.-C., Definition of magnetic exchange length, IEEE Trans. Magn., 49, pp. 4937-4939, (2013)","H. Yetiş; Abant Izzet Baysal University, Physics Department, Bolu, Gölköy Campus, 14280, Turkey; email: hknyetis@gmail.com","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84984919501" +"Al-Rashid M.M.; Bhattacharya D.; Bandyopadhyay S.; Atulasimha J.","Al-Rashid, Md Mamun (56780087100); Bhattacharya, Dhritiman (56779559900); Bandyopadhyay, Supriyo (57203099871); Atulasimha, Jayasimha (6508238509)","56780087100; 56779559900; 57203099871; 6508238509","Effect of Nanomagnet Geometry on Reliability, Energy Dissipation, and Clock Speed in Strain-Clocked DC-NML","2015","IEEE Transactions on Electron Devices","62","9","7182756","2978","2986","8","14","10.1109/TED.2015.2453118","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85027943254&doi=10.1109%2fTED.2015.2453118&partnerID=40&md5=afc3edcedcfcd3161ac81c0a01b93723","Department of Mechanical and Nuclear Engineering, Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States","Al-Rashid M.M., Department of Mechanical and Nuclear Engineering, Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Bhattacharya D., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Bandyopadhyay S., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States; Atulasimha J., Department of Mechanical and Nuclear Engineering, Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, 23284, VA, United States","Strain-clocked dipole-coupled nanomagnetic logic (DC-NML) is an energy-efficient Boolean logic paradigm whose progress has been stymied by its propensity for high error rates. In an effort to mitigate this problem, we have studied the effect of nanomagnet geometry on error rates, focusing on elliptical and cylindrical geometries. We had previously reported that in elliptical nanomagnets, the out-of-plane excursion of the magnetization vector during switching creates a precessional torque that plays a dual role-it speeds up the switching, but is also responsible for the high switching error probability. The absence of this torque in cylindrical magnets should lower error rates, but our simulations show that the error rate actually does not improve significantly compared with elliptical magnets while the switching becomes unacceptably slow. Here, we show that DC-NML employing elliptical nanomagnets can offer relatively high reliability for NML (switching error probability < 10^{-8} ), moderate clock speed ( \sim 100 MHz), and two to three orders of magnitude energy saving compared with CMOS devices, provided the shape anisotropy energy barrier of the nanomagnet is increased to at least \sim 5.5 eV to allow engineering a stronger dipole coupling between neighboring nanomagnets. © 1963-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; nanomagnetic logic (NML); reliability; straintronics-spintronics; thermal noise.","Clocks; CMOS integrated circuits; Cylinders (shapes); Energy conservation; Energy dissipation; Energy efficiency; Errors; Geometry; Magnets; Reliability; Switching; Thermal noise; Cylindrical geometry; Cylindrical magnets; Landau-Lifshitz-Gilbert equations; Magnetization vector; Nanomagnetic logic; Nanomagnetic logic (NML); Precessional torques; Three orders of magnitude; Nanomagnetics","","","","","National Science Foundation, (CCF-1253370); National Science Foundation, NSF, (1253370)","","Cowburn R.P., Welland M.E., Room temperature magnetic quantum cellular automata, Science, 287, 5457, pp. 1466-1468, (2000); Csaba G., Imre A., Bernstein G.H., Porod W., Metlushko V., Nanocomputing by field-coupled nanomagnets, IEEE Trans. Nanotechnol, 1, 4, pp. 209-213, (2002); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Single-domain circular nanomagnets, Phys. Rev. Lett, 83, 5, pp. 1042-1045, (1999); Niemier M.T., Et al., Nanomagnet logic: Progress toward system-level integration, J. Phys., Condens. Matter, 23, 49, (2011); Ralph D.C., Stiles M.D., Spin transfer torques, J. Magn. Magn. Mater, 320, 7, pp. 1190-1216, (2008); Becherer M., Et al., Towards on-chip clocking of perpendicular nanomagnetic logic, Solid-State Electron, 102, pp. 46-51, (2014); Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using multiferroic single-domain nanomagnets, Appl. Phys. Lett, 97, 17, (2010); D'Souza N., Fashami M.S., Bandyopadhyay S., Atulasimha J., Experimental Clocking of Nanomagnets with Strain for Ultra Low Power Boolean Logic, (2014); Bhowmik D., You L., Salahuddin S., Spin Hall effect clocking of nanomagnetic logic without a magnetic field, Nature Nanotechnol, 9, 1, pp. 59-63, (2014); Fashami M.S., Munira K., Bandyopadhyay S., Ghosh A.W., Atulasimha J., Switching of dipole coupled multiferroic nanomagnets in the presence of thermal noise: Reliability of nanomagnetic logic, IEEE Trans. Nanotechnol, 12, 6, pp. 1206-1212, (2013); Spedalieri F.M., Jacob A.P., Nikonov D.E., Roychowdhury V.P., Performance of magnetic quantum cellular automata and limitations due to thermal noise, IEEE Trans. Nanotechnol, 10, 3, pp. 537-546, (2011); Munira K., Xie Y., Nadri S., Forgues M.B., Fashami M.S., Atulasimha J., Bandyopadhyay S., Ghosh A.W., Reducing error rates in straintronic multiferroic nanomagnetic logic by pulse shaping, Nanotechnology, 26, 24, (2015); Carlton D., Et al., Investigation of defects and errors in nanomagnetic logic circuits, IEEE Trans. Nanotechol, 11, 4, pp. 760-762, (2012); Csaba G., Porod W., Behavior of nanomagnet logic in the presence of thermal noise, Proc. 14th Int. Workshop Comput. Electron., pp. 1-4, (2011); Fashami M.S., Atulasimha J., Bandyopadhyay S., Energy dissipation and error probability in fault-Tolerant binary switching, Sci. Rep, 3, (2013); Chen D.-X., Brug J.A., Goldfarb R.B., Demagnetizing factors for cylinders, IEEE Trans. Nanotechnol, 27, 4, pp. 3601-3619, (1991); Wolf S.A., Lu J., Stan M.R., Chen E., Treger D.M., The promise of nanomagnetics and spintronics for future logic and universal memory, Proc IEEE, 98, 12, pp. 2155-2168, (2010); Comes R., Liu H., Khokhlov M., Kasica R., Lu J., Wolf S.A., Directed self-Assembly of epitaxial CoFe2O4-BiFeO3 multiferroic nanocomposites, Nano Lett, 12, 5, pp. 2367-2373, (2012); Chikazumi S., Magnetostatic phenomena, Physics of Ferromagnetism, (1997); Roy K., Bandyopadhyay S., Atulasimha J., Binary switching in a 'symmetric' potential landscape, Sci. Rep, 3, (2013); Mayergoyz I.D., Bertotti G., Serpico C., Stochastic magnetization dynamics, Nonlinear Magnetization Dynamics in Nanosystems, (2009); Fashami M.S., Roy K., Atulasimha J., Bandyopadhyay S., Magnetization dynamics, Bennett clocking and associated energy dissipation in multiferroic logic, Nanotechnology, 22, 15, (2011); Cui J., Hockel J.L., Nordeen P.K., Pisani D.M., Carman G.P., Lynch C.S., Giant electric-field-induced magnetic anisotropy reorientation with patterned electrodes on a Ni thin film/lead zirconate titanate heterostructure, J. Appl. Phys, 115, 17, (2014); Datta S., Diep V.Q., Behin-Aein B., What constitutes a nanoswitch? A perspective, Emerging Nanoelectronic Devices, pp. 15-34, (2014); The Object Oriented MicroMagnetic Framework (OOMMF); Yi M., Xu B.-X., Shen Z., 180° magnetization switching in nanocylinders by a mechanical strain, Extreme Mech. Lett, 3, pp. 67-71, (2015)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85027943254" +"Ostwal V.; Debashis P.; Faria R.; Chen Z.; Appenzeller J.","Ostwal, Vaibhav (57204628212); Debashis, Punyashloka (56044811200); Faria, Rafatul (7103325154); Chen, Zhihong (57215374701); Appenzeller, Joerg (7004434792)","57204628212; 56044811200; 7103325154; 57215374701; 7004434792","Spin-torque devices with hard axis initialization as Stochastic Binary Neurons","2018","Scientific Reports","8","1","16689","","","","28","10.1038/s41598-018-34996-2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85056309543&doi=10.1038%2fs41598-018-34996-2&partnerID=40&md5=c904abe0c50ed99383a8586cff14ab66","School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States; Birck Nanotechnology Center, Purdue University, West Lafayette, 47907, IN, United States","Ostwal V., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States, Birck Nanotechnology Center, Purdue University, West Lafayette, 47907, IN, United States; Debashis P., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States, Birck Nanotechnology Center, Purdue University, West Lafayette, 47907, IN, United States; Faria R., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States; Chen Z., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States, Birck Nanotechnology Center, Purdue University, West Lafayette, 47907, IN, United States; Appenzeller J., School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, IN, United States, Birck Nanotechnology Center, Purdue University, West Lafayette, 47907, IN, United States","Employing the probabilistic nature of unstable nano-magnet switching has recently emerged as a path towards unconventional computational systems such as neuromorphic or Bayesian networks. In this letter, we demonstrate proof-of-concept stochastic binary operation using hard axis initialization of nano-magnets and control of their output state probability (activation function) by means of input currents. Our method provides a natural path towards addition of weighted inputs from various sources, mimicking the integration function of neurons. In our experiment, spin orbit torque (SOT) is employed to “drive” nano-magnets with perpendicular magnetic anisotropy (PMA) -to their metastable state, i.e. in-plane hard axis. Next, the probability of relaxing into one magnetization state (+mi) or the other (−mi) is controlled using an Oersted field generated by an electrically isolated current loop, which acts as a “charge” input to the device. The final state of the magnet is read out by the anomalous Hall effect (AHE), demonstrating that the magnetization can be probabilistically manipulated and output through charge currents, closing the loop from charge-to-spin and spin-to-charge conversion. Based on these building blocks, a two-node directed network is successfully demonstrated where the status of the second node is determined by the probabilistic output of the previous node and a weighted connection between them. We have also studied the effects of various magnetic properties, such as magnet size and anisotropic field on the stochastic operation of individual devices through Monte Carlo simulations of Landau Lifshitz Gilbert (LLG) equation. The three-terminal stochastic devices demonstrated here are a critical step towards building energy efficient spin based neural networks and show the potential for a new application space. © 2018, The Author(s).","","Animals; Anisotropy; Bayes Theorem; Humans; Magnets; Microscopy, Electron, Scanning; Monte Carlo Method; Neurons; animal; anisotropy; Bayes theorem; human; magnet; Monte Carlo method; nerve cell; scanning electron microscopy","","","","","Semiconductor Research Corporation, SRC; Directorate for Computer and Information Science and Engineering, CISE, (CCF 1739635); Directorate for Computer and Information Science and Engineering, CISE; National Science Foundation, NSF, (CCF 1739635); National Science Foundation, NSF","","Quang Diep V., Sutton B., Behin-Aein B., Datta S., Spin switches for compact implementation of neuron and synapse, Appl. Phys. Lett., 104, (2014); Shim Y., Chen S., Sengupta A., Roy K., Stochastic Spin-Orbit Torque Devices as Elements for Bayesian Inference, Sci. Rep., 7, pp. 1-9, (2017); Faria R., Camsari K.Y., Datta S., Implementing Bayesian networks with embedded stochastic MRAM, AIP Adv., 8, (2018); Behin-Aein B., Diep V., Datta S., A building block for hardware belief networks, Sci. Rep., 6, pp. 1-10, (2016); Shim Y., Jaiswal A., Roy K., Ising computation based combinatorial optimization using spin-Hall effect (SHE) induced stochastic magnetization reversal, J. Appl. Phys., 121, (2017); Debashis P., Et al., Experimental demonstration of nanomagnet networks as hardware for Ising computing, Tech. Dig. - Int. Electron Devices Meet. IEDM, pp. 1-34, (2017); Camsari K.Y., Faria R., Sutton B.M., Datta S., Stochastic p-bits for invertible logic, Phys. Rev. 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Phys., 122, (2017); Bassham L.E., Et al., A Statistical Test Suite for Random and Pseudorandom Number Generators for Cryptographic Applications, (2010); Fukushima A., Et al., Spin dice: A scalable truly random number generator based on spintronics, Appl. Phys. Express, 7, (2014); Liu L., Lee O.J., Gudmundsen T.J., Ralph D.C., Buhrman R.A., Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin hall effect, Phys. Rev. Lett., 109, 96602, pp. 1-5, (2012); Scott W., Nikonov D.E., Jeffrey J., Young I.A., Heard B., Hybrid Piezoelectric-Magnetic Neurons: A Proposal for Energy- EfficientMachine Learning, Proc. ACMSE 2018 Conf. ACM, pp. 3-7, (2018); Sengupta A., Choday S.H., Kim Y., Roy K., Spin orbit torque based electronic neuron, Appl. Phys. Lett., 106, (2015); Kim K., Et al., Dynamic energy-accuracy trade-off using stochastic computing in deep neural networks, Proc. 53Rd Annu. Des. Autom. Conf. - DAC ’16, pp. 1-6, (2016)","V. Ostwal; School of Electrical and Computer Engineering, Purdue University, West Lafayette, 47907, United States; email: vostwal@purdue.edu","","Nature Publishing Group","","","","","","20452322","","","30420701","English","Sci. Rep.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85056309543" +"Petrović M.D.; Popescu B.S.; Bajpai U.; Plecháč P.; Nikolić B.","Petrović, Marko D. (55928482300); Popescu, Bogdan S. (57191291443); Bajpai, Utkarsh (57204777363); Plecháč, Petr (6602756545); Nikolić, Branislavk. (7006055333)","55928482300; 57191291443; 57204777363; 6602756545; 7006055333","Spin and Charge Pumping by a Steady or Pulse-Current-Driven Magnetic Domain Wall: A Self-Consistent Multiscale Time-Dependent Quantum-Classical Hybrid Approach","2018","Physical Review Applied","10","5","054038","","","","47","10.1103/PhysRevApplied.10.054038","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85057080061&doi=10.1103%2fPhysRevApplied.10.054038&partnerID=40&md5=10778a14c9164392e2ac122ece69daa4","Department of Mathematical Sciences, University of Delaware, Newark, 19716, DE, United States; Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus UAB, Bellaterra, Barcelona, 08193, Spain","Petrović M.D., Department of Mathematical Sciences, University of Delaware, Newark, 19716, DE, United States; Popescu B.S., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Bajpai U., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States; Plecháč P., Department of Mathematical Sciences, University of Delaware, Newark, 19716, DE, United States; Nikolić B., Department of Physics and Astronomy, University of Delaware, Newark, 19716, DE, United States, Catalan Institute of Nanoscience and Nanotechnology (ICN2), Campus UAB, Bellaterra, Barcelona, 08193, Spain","We introduce a multiscale framework that combines a time-dependent nonequilibrium Green-function (TDNEGF) algorithm, scaling linearly in the number of time steps and describing quantum-mechanically the conduction electrons in the presence of time-dependent fields of arbitrary strength or frequency, with classical time evolution of localized magnetic moments described by the Landau-Lifshitz-Gilbert (LLG) equation. The TDNEGF+LLG framework can be applied to a variety of problems where current-driven spin torque induces the dynamics of magnetic moments as the key resource for next-generation spintronics. Previous approaches to such nonequilibrium many-body systems (like the steady-state-NEGF+LLG framework) neglect noncommutativity of a quantum Hamiltonian of conduction electrons at different times and, therefore, the impact of time-dependent magnetic moments on electrons leading to the pumping of spin and charge currents. The pumped currents can, in turn, self-consistently affect the dynamics of magnetic moments themselves. Using the magnetic domain wall (DW) as an example, we predict that its motion will pump time-dependent spin and charge currents (on top of the unpolarized dc charge current injected through normal-metal leads to drive the DW motion), where the latter can be viewed as a realization of quantum charge pumping due to the time dependence of the Hamiltonian and the left-right symmetry breaking of the two-terminal device structure. The conversion of ac components of spin current, whose amplitude increases (decreases) as the DW approaches (recedes from) the normal-metal lead, into ac voltage via the inverse spin Hall effect offers a tool to precisely track the DW position along magnetic nanowire. We also quantify the DW transient inertial displacement due to its acceleration and deceleration by pulse current and the entailed spin and charge pumping. Finally, TDNEGF+LLG as a nonperturbative (i.e., numerically exact) framework allows us to establish the limits of validity of the so-called spin-motive force (SMF) theory for pumped charge current by time-dependent magnetic textures - the perturbative analytical formula of SMF theory becomes inapplicable for large frequencies (but unrealistic in a magnetic system) and, more importantly, for increasing noncollinearity when the angles between neighboring magnetic moments exceed approximately 10. © 2018 American Physical Society.","","Domain walls; Hamiltonians; Magnetic domains; Magnetic moments; Optical pumping; Quantum optics; Spin dynamics; Textures; Acceleration and deceleration; Landau-Lifshitz-Gilbert equations; Localized magnetic moments; Multi-scale frameworks; Non-equilibrium green functions; Quantum Hamiltonians; Time-dependent fields; Two-terminal devices; Spin Hall effect","","","","","Norsk Sykepleierforbund, NSF, (ACI-1548562, CHE 1566074); Norsk Sykepleierforbund, NSF","M.D.P. and P.P. are supported by ARO MURI Grant No. W911NF-14-0247. B.S.P., U.B., and B.K.N. are supported by NSF Grant No. CHE 1566074. The supercomputing time is provided by XSEDE, which is supported by NSF Grant No. ACI-1548562.","Ralph D., Stiles M., Spin transfer torques, J. Magn. Magn. Mater., 320, (2008); Xiao J., Zangwill A., Stiles M.D., Macrospin models of spin transfer dynamics, Phys. Rev. B, 72, (2005); Berkov D.V., Miltat J., Spin-torque driven magnetization dynamics: Micromagnetic modeling, J. Magn. Magn. Mater., 320, (2008); Yamaguchi A., Ono T., Nasu S., Miyake K., Mibu K., Shinjo T., Real-Space Observation of Current-Driven Domain Wall Motion in Submicron Magnetic Wires, Phys. Rev. Lett., 92, (2004); Tatara G., Kohno H., Shibata J., Microscopic approach to current-driven domain wall dynamics, Phys. Rep., 468, (2008); Kim K.-J., Yoshimura Y., Ono T., Current-driven magnetic domain wall motion and its real-time detection, Jap. J. Appl. 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B, 93, (2016); Jungfleisch M.B., Zhang W., Hoffmann A., Perspectives of antiferromagnetic spintronics, Phys. Lett. A, 382, (2018); Rhensius J., Heyne L., Backes D., Krzyk S., Heyderman L.J., Joly L., Nolting F., Klaui M., Imaging of Domain Wall Inertia in Permalloy Half-Ring Nanowires by Time-Resolved Photoemission Electron Microscopy, Phys. Rev. Lett., 104, (2010); Dolui K., Nikolic B.K., Spin-memory loss due to spin-orbit coupling at ferromagnet/heavy-metal interfaces: Ab initio spin-density matrix approach, Phys. Rev. B, 96, (2017); Kim S.K., Tserkovnyak Y., Magnetic Domain Walls as Hosts of Spin Superfluids and Generators of Skyrmions, Phys. Rev. Lett., 119, (2017)","","","American Physical Society","","","","","","23317019","","","","English","Phys. Rev. Appl.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-85057080061" +"Bisotti M.-A.; Cortés-Ortuño D.; Pepper R.; Wang W.; Beg M.; Kluyver T.; Fangohr H.","Bisotti, Marc-Antonio (56536952300); Cortés-Ortuño, David (55014210800); Pepper, Ryan (57193415152); Wang, Weiwei (46761490700); Beg, Marijan (56536080000); Kluyver, Thomas (57194588430); Fangohr, Hans (6602681314)","56536952300; 55014210800; 57193415152; 46761490700; 56536080000; 57194588430; 6602681314","Fidimag – A Finite Difference Atomistic and Micromagnetic Simulation Package","2018","Journal of Open Research Software","6","","","1","11","10","39","10.5334/jors.223","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85099012614&doi=10.5334%2fjors.223&partnerID=40&md5=f121c8fb5b1e80ab4844c0843f23d426","Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Department of Physics, Ningbo University, Ningbo, 315211, China; European XFEL, DE, Schenefeld, 22869, United Kingdom","Bisotti M.-A., Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Cortés-Ortuño D., Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Pepper R., Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Wang W., Department of Physics, Ningbo University, Ningbo, 315211, China; Beg M., European XFEL, DE, Schenefeld, 22869, United Kingdom; Kluyver T., Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom, European XFEL, DE, Schenefeld, 22869, United Kingdom; Fangohr H., Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom, European XFEL, DE, Schenefeld, 22869, United Kingdom","Fidimag is an open-source scientific code for the study of magnetic materials at the nano- or micro-scale using either atomistic or finite difference micromagnetic simulations, which are based on solving the Landau-Lifshitz-Gilbert equation. In addition, it implements simple procedures for calculating energy barriers in the magnetisation through variants of the nudged elastic band method. This computer software has been developed with the aim of creating a simple code structure that can be readily installed, tested, and extended. An agile development approach was adopted, with a strong emphasis on automated builds and tests, and reproducibility of results. The main code and interface to specify simulations are written in Python, which allows simple and readable simulation and analysis configuration scripts. Computationally costly calculations are written in C and exposed to the Python interface as Cython extensions. Docker containers are shipped for a convenient setup experience. The code is freely available on GitHub and includes documentation and examples in the form of Jupyter notebooks. © 2018. The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.","Cython; domain walls; finite differences; Landau-Lifshitz-Gilbert; LLG; micromagnetic simulations; micromagnetism; nanomaterials; Python; skyrmions; spin-transfer torque; vortex; vortices","","","","","","CONICYT Chilean scholarship programme Becas Chile, (72140061); Helmsley Trust; Alfred P. Sloan Foundation, APSF; Gordon and Betty Moore Foundation, GBMF, (GBMF #4856); Horizon 2020 Framework Programme, H2020, (676541); HORIZON EUROPE Research Infrastructures; Engineering and Physical Sciences Research Council, EPSRC, (EP/G03690X/1, EP/L015382/1); National Natural Science Foundation of China, NSFC, (11604169)","Funding text 1: Keywords: Python; Cython; finite differences; nanomaterials; micromagnetism; Landau-Lifshitz-Gilbert; LLG; spin-transfer torque; micromagnetic simulations; domain walls; skyrmions; vortex; vortices Funding Statement: We acknowledge financial support from EPSRC’s Centre for Doctoral Training in Next Generation Computational Modelling, (EP/L0? 382/? , EPSRC’s Doctoral Training Centre in Complex System Simulation (EP/G03690X/? , CONICYT Chilean scholarship programme Becas Chile (72? 006? , Horizon 2020 European Research Infrastructure project OpenDreamKit (67654? , National Natural Science Foundation of China (? 04? 9) , and the Gordon and Betty Moore Foundation through Grant GBMF ? 856, b y the Alfred P. Sloan Foundation and by the Helmsley Trust.; Funding text 2: We acknowledge financial support from EPSRC’s Centre for Doctoral Training in Next Generation Computational Modelling, (EP/L015382/1), EPSRC’s Doctoral Training Centre in Complex System Simulation (EP/G03690X/1), CONICYT Chilean scholarship programme Becas Chile (72140061), Horizon 2020 European Research Infrastructure project OpenDreamKit (676541), National Natural Science Foundation of China (11604169), and the Gordon and Betty Moore Foundation through Grant GBMF #4856, by the Alfred P. Sloan Foundation and by the Helmsley Trust.","Evans R F L, Fan W J, Chureemart P, Ostler T A, Ellis M O A, Chantrell R W, Atomistic spin model simulations of magnetic nanomaterials, Journal of Physics: Condensed Matter, 26, 10, (2014); Wang W, Albert M, Beg M, Bisotti M-A, Chernyshenko D, Cortes-Ortuno D, Hawke I, Fangohr H, Magnon-driven domain-wall motion with the dzyaloshinskii-moriya interaction, Phys. Rev. Lett, 114, (2015); Wang W, Beg M, Zhang B, Kuch W, Fangohr H, Driving magnetic skyrmions with microwave fields, Phys. Rev. B, 92, (2015); Cortes-Ortuno D, Wang W, Beg M, Pepper R A, Bisotti M-A, Carey R, Vousden M, Kluyver T, Hovorka O, Fangohr H, Thermal stability and topological protection of skyrmions in nanotracks, Scientific Reports, 7, 1, (2017); Wang W, Zhang C, Pepper R, Mu C, Zhou Y, Fangohr H, Current-induced instability of domain walls in cylindrical nanowires, Journal of Physics: Condensed Matter, (2017); Cortes-Ortuno D, Fangohr H, Thermal stability and topological protection of skyrmions: Supplementary data, (2016); Aharoni A, Introduction to the Theory of Ferromagnetism, 109, (2000); Chikazumi S, Physics of Ferromagnetism, volume 94 of International Series of Monographs on Physics, (2009); Fidimag Documentation – core equations; Fidimag Documentation – extended equations; Fischbacher T, Fangohr H, Continuum multi-physics modeling with scripting languages: The Nsim simulation compiler prototype for classical field theory, (2009); Fischbacher T, Franchin M, Bordignon G, Fangohr H, A systematic approach to multiphysics extensions of finite-element-based micromagnetic simulations: Nmag, IEEE Transactions on Magnetics, 43, 6, pp. 2896-2898, (2007); Hindmarsh A C, Brown P N, Grant K E, Lee S L, Serban R, Shumaker D E, Woodward C S, SUNDIALS: Suite of nonlinear and differential/algebraic equation solvers, ACM Transactions on Mathematical Software (TOMS), 31, 3, pp. 363-396, (2005); Jones E, Oliphant T, Peterson P, Et al., SciPy: Open source scientific tools for Python, (2001); Henkelman G, Uberuaga B P, Jonsson H, A climbing image nudged elastic band method for finding saddle points and minimum energy paths, The Journal of Chemical Physics, 113, 22, pp. 9901-9904, (2000); Bessarab P F, Uzdin V M, Jonsson H, Method for finding mechanism and activation energy of magnetic transitions, applied to skyrmion and antivortex annihilation, Computer Physics Communications, 196, pp. 335-347, (2015); Cortes-Ortuno D, Fangohr H, Test system for nudged elastic band method in nanoscale magnetism, (2016); Beazley D M, Scientific Computing with Python, Astronomical Data Analysis Software and Systems IX, Astronomical Society of the Pacific Conference Series, 216, (2000); Fangohr H, A comparison of C, Matlab, and Python as teaching languages in engineering, Computational Science – ICCS 2004, pp. 1210-1217, (2004); Fangohr H, Albert M, Franchin M, Nmag micromagnetic simulation tool: Software engineering lessons learned, Proceedings of the International Workshop on Software Engineering for Science, SE4Science ’16, pp. 1-7, (2016); Beg M, Pepper R A, Fangohr H, User interfaces for computational science: A domain specific language for oommf embedded in python, AIP Advances, 7, 5, (2017); Beg M, Pepper R A, Fangohr H, User interfaces for computational science: A domain specific language for oommf embedded in python, AIP Advances, 7, 5, (2017); Fowler M, Refactoring: Improving the Design of Existing Code, (1999); Davison A, Automated capture of experiment context for easier reproducibility in computational research, Computing in Science & Engineering, 14, pp. 48-56, (2012); Kluyver T, Ragan-Kelley B, Perez F, Granger B, Bussonnier M, Frederic J, Kelley K, Hamrick J, Grout J, Corlay S, Ivanov P, Avila D, Abdalla S, Willing C, Jupyter notebooks – a publishing format for reproducible computational workflows, (2016); Fidimag Documentation; Cortes-Ortuno D, Laslett O, Kluyver T, Fauske V, Albert M, Min RK, Hovorka O, Fangohr H, nbval: a py.test plugin for validating jupyter notebooks, (2014); Travis CI GmbH computationalmodelling/fidimag - travis ci; van der Walt S, Colbert S C, Varoquaux G, The numpy array: A structure for efficient numerical computation, Computing in Science Engineering, 13, 2, pp. 22-30, (2011); Yuan S W, Bertram H N, Fast adaptive algorithms for micromagnetics, IEEE Transactions on Magnetics, 28, 5, pp. 2031-2036, (1992); Hayashi N, Saito K, Nakatani Y, Calculation of demagnetizing field distribution based on fast fourier transform of convolution, Japanese Journal of Applied Physics, 35, 12R, (1996); Hinzke D, Nowak U, Magnetization switching in nanowires: Monte carlo study with fast fourier transformation for dipolar fields, Journal of Magnetism and Magnetic Materials, 221, 3, pp. 365-372, (2000); Codecov LLC Dashboard computational modelling/fidimag; Fidimag Tutorial: A basic simulation","M.-A. Bisotti; Faculty of Engineering and the Environment, University of Southampton, Southampton, SO17 1BJ, United Kingdom; email: mb8g11@soton.ac.uk","","Ubiquity Press","","","","","","20499647","","","","English","J. Open Res. Softw","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-85099012614" +"Chen B.; Gao S.; Qu Y.; Xu N.; Zhao Y.","Chen, Bing (55539893000); Gao, Shifan (57209176414); Qu, Yiming (57193324378); Xu, Nuo (7202694801); Zhao, Yi (7406634019)","55539893000; 57209176414; 57193324378; 7202694801; 7406634019","An Euler-Lagrange Equation Oriented Solution for Write Energy Minimization of STT-MRAM","2019","IEEE Transactions on Electron Devices","66","8","8755320","3686","3689","3","2","10.1109/TED.2019.2922254","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85069939813&doi=10.1109%2fTED.2019.2922254&partnerID=40&md5=4bbafe55a68fc2a1be44fedd1d74bd75","College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China","Chen B., College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China; Gao S., College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China; Qu Y., College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China; Xu N., College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China; Zhao Y., College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China","In this brief, for the first time, an Euler-Lagrange equation oriented solution for minimizing the operation energy of state-of-the-art spin-transfer-torque magnetoresistance random access memory (STT-MRAM) is proposed. Utilizing the derived analytical solvable Landau-Lifshitz-Gilbert (LLG) model and Euler-Lagrange equation, a calculable method for minimizing the dynamic energy of STT-MRAM is founded. Experimentally, a write energy reduction by 30% is demonstrated in the context of a certain write error rate. This brief provides a pragmatic method for achieving high energy-efficiency and reliable STT-MRAM operations. © 1963-2012 IEEE.","Euler-Lagrange equation; Landau-Lifshitz-Gilbert (LLG) equation; online optimization; STT-MRAM; write error rate (WER)","Energy efficiency; Equations of motion; Lagrange multipliers; Magnetic recording; Magnetic storage; Random access storage; Error rate; Euler-Lagrange equations; Landau-Lifshitz-Gilbert equations; Online optimization; STT-MRAM; MRAM devices","","","","","Technology of China; National Natural Science Foundation of China, NSFC, (61704152); National Natural Science Foundation of China, NSFC; National Basic Research Program of China (973 Program), (2017YFA0207600); National Basic Research Program of China (973 Program); Fundamental Research Funds for the Central Universities, (2017ZX02315001-007); Fundamental Research Funds for the Central Universities; National Major Science and Technology Projects of China; Science and Technology Major Project of Guangxi","Funding text 1: This work was supported in part by National Key Research and Development Program under Grant 2017YFA0207600, in part by NSFC under Grant 61704152, in part by the National Science and Technology Major Project of the Ministry of Science, and in part by the Technology of China, the Fundamental Research Funds for the Central Universities, under Grant 2017ZX02315001-007.; Funding text 2: Manuscript received April 17, 2019; revised June 2, 2019; accepted June 7, 2019. Date of publication July 3, 2019; date of current version July 23, 2019. This work was supported in part by National Key Research and Development Program under Grant 2017YFA0207600, in part by NSFC under Grant 61704152, in part by the National Science and Technology Major Project of the Ministry of Science, and in part by the Technology of China, the Fundamental Research Funds for the Central Universities, under Grant 2017ZX02315001-007. The review of this brief was arranged by Editor T. Kim. (Bing Chen and Shifan Gao contributed equally to this paper.) (Corresponding author: Yi Zhao.) B. Chen, S. Gao, and Y. Qu are with the College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou 310027, China.","Lu Y., Et al., Fully functional perpendicular STT-MRAM macro embedded in 40 nm logic for energy-efficient IOT applications, IEDM Tech. Dig., pp. 2611-2614, (2015); Park C., Et al., Systematic optimization of 1 Gbit perpendicular magnetic tunnel junction arrays for 28 nm embedded STT-MRAM and beyond, IEDM Tech. Dig., pp. 2621-2624, (2015); Chung S.-W., Et al., 4Gbit density STT-MRAM using perpendicular MTJ realized with compact cell structure, IEDM Tech. Dig., pp. 2711-2714, (2016); Kan J.J., Et al., Systematic validation of 2× nm diameter perpendicular MTJ arrays and MgO barrier for sub-10 nm embedded STT-MRAM with practically unlimited endurance, IEDM Tech. Dig., pp. 2741-2744, (2016); Ikeda S., Et al., A perpendicular-Anisotropy CoFeB-MgO magnetic tunnel junction, Nature Mater., 9, pp. 721-724, (2010); Yuasa S., Et al., Future prospects of MRAM technologies, IEDM Tech. Dig., pp. 311-314, (2013); Hu G., Et al., STT-MRAM with double magnetic tunnel junctions, IEDM Tech. Dig., pp. 2631-2634, (2015); Swerts J., Et al., Solving the BEOL compatibility challenge of top-pinned magnetic tunnel junction stacks, IEDM Tech. Dig., pp. 3861-3864, (2017); Yang K., Et al., A 28NM integrated true random number generator harvesting entropy from MRAM, Proc. IEEE Symp. VLSI Technol., pp. 171-172, (2018); Xu N., Et al., STT-MRAM design technology co-optimization for hardware neural networks, IEDM Tech. Dig., pp. 1531-1534, (2018); Xu N., Et al., Rare-failure oriented STT-MRAM technology optimization, Proc. IEEE Symp. VLSI Technol., pp. 187-188, (2018); Chen B., Et al., A novel operation scheme for oxide-based resistiveswitching memory devices to achieve controlled switching behaviors, IEEE Electron Devices Lett., 32, 3, pp. 282-284, (2011); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1-2, pp. L1-L7, (1996); Slonczewski J.C., Currents, torques, and polarization factors in magnetic tunnel junctions, Phys. Rev. B, 71, (2005); Slonczewski J.C., Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier, Phys. Rev. B, 39, pp. 6995-7002, (1989); Weisstein E., Brachistochrone Problem, from MathWorld-A Wolfram Web Resource; Qu Y., Chen B., Liu W., Han J., Lu J., Zhao Y., Sub-1 ns characterization methodology for transistor electrical parameter extraction, Microelectron. Rel., 85, pp. 93-98, (2018); Gao S., Chen B., Xu N., Qu Y., Zhao Y., Probing write error rate and random telegraph noise of mgo based magnetic tunnel juction using a high throughput characterization system, Proc. IEEE Int. Rel. Phys. Symp. (IRPS), pp. 1-4, (2019)","Y. Zhao; College of Electronic Engineering and Information Science, Zhejiang University, Hangzhou, China; email: yizhao@zju.edu.cn","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-85069939813" +"Manago T.; Aziz M.M.; Ogrin F.; Kasahara K.","Manago, Takashi (56021955300); Aziz, Mustafa M. (7103236089); Ogrin, Feodor (57193655015); Kasahara, Kenji (36054641300)","56021955300; 7103236089; 57193655015; 36054641300","Influence of the conductivity on spin wave propagation in a Permalloy waveguide","2019","Journal of Applied Physics","126","4","043904","","","","8","10.1063/1.5110202","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85070070075&doi=10.1063%2f1.5110202&partnerID=40&md5=dbaadb2a2c40804d670f845844153406","Department of Applied Physics, Fukuoka University, Fukuoka, 814-0180, Japan; Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, United Kingdom; College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, United Kingdom","Manago T., Department of Applied Physics, Fukuoka University, Fukuoka, 814-0180, Japan, Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, United Kingdom; Aziz M.M., College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QF, United Kingdom; Ogrin F., Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, United Kingdom; Kasahara K., Department of Applied Physics, Fukuoka University, Fukuoka, 814-0180, Japan","The influence of the electrical conductivity of a Permalloy waveguide on the spin wave propagation was investigated using the finite-element solution of the combined system of quasistatic electromagnetic potential and linearized LLG (Landau-Lifshitz-Gilbert) equations. The difference in the group velocity between the conductive and nonconductive waveguides becomes large for films over 300 nm thick, and the difference is very small for film thicknesses less than 100 nm. The observed enhancement of the group velocity with increasing film thickness is attributed to the damping caused by the electrical conductivity, which leads to narrowing of the spin wave packet envelope and shorter arrival times of propagating waves. The basic characteristics of the dispersion relations do not change between conductive and nonconductive films for small film thicknesses less than 300 nm. The simulated dispersion relations indicate shift of their maximum intensity toward lower wavenumbers and, therefore, increase in the group velocity with increasing thickness. The simulated decay length of the spin waves for conductive films initially increases but then decreases with increasing thickness, which agrees well with the experimental results. The extracted damping coefficients from both simulations and the experiment agree very well and increase proportionally with d2, where d is the film thickness, due to the additional eddy current damping. The observed thickness and conductivity dependence of spin wave propagation is crucial for magnonics research and toward the development of future spin wave devices using metal films. © 2019 Author(s).","","Conductive films; Damping; Eddy current testing; Electric conductivity; Film thickness; Iron alloys; Light velocity; Multilayers; Nickel alloys; Permalloy; Quantum theory; Spin waves; Wave propagation; Waveguides; Basic characteristics; Damping coefficients; Dispersion relations; Eddy-current damping; Electrical conductivity; Electromagnetic potentials; Finite element solution; Landau-Lifshitz-Gilbert; Dispersion (waves)","","","","","Japan Society for the Promotion of Science, JSPS, (15K06000, 167003, 175005, 24560034); Central Research Institute, Fukuoka University","T.M. would like to thank Professor V. V. Kruglyak for fruitful discussions. This work was partly supported by the JSPS KAKENHI (Grant Nos. 24560034 and 15K06000). This work was supported in part by funds (Nos. 167003 and 175005) from the Central Research Institute of Fukuoka University.","Kruglyak V.V., Demokritov S.O., Grundler D., J. Phys. D, 43, (2010); Khitun A., Bao M., Wang K.L., J. Phys. D, 43, (2010); Lenk B., Ulrichs H., Garbs F., Munzenberg M., Phys. Rep., 507, (2011); Au Y., Dvornik M., Dmytriiev O., Kruglyak V.V., Appl. Phys. Lett., 100, (2012); Khitun A., J. Appl. Phys., 111, (2012); Chumak A.V., Serga A.A., Hillebrands B., Nat. Commun., 5, (2014); Vogt K., Fradin F.Y., Pearson J.E., Sebastian T., Badar S.D., Hillbrands B., Hoffmann A., Schultheiss H., Nat. Commun., 5, (2014); Vogel M., Chumak A.V., Waller E.H., Langner T., Vasyuchka V.I., Hillebrands B., Von Freymann G., Nat. Phys., 11, (2015); Chumak A.V., Vasyuchka V.I., Serga A.A., Hillebrands B., Nat. Phys., 11, (2015); Kanazawa N., Goto T., Sekiguchi K., Granovsky A.B., Ross C.A., Takagi H., Nakamura Y., Inoue M., Sci. Rep., 6, (2016); Haldar A., Kumar D., Adeyeye A.O., Nat. Nanotech., 11, (2016); Cornelissen L.J., Liu J., Wees B.J.V., Duine R.A., Phys. Rev. Lett., 120, (2018); Bailleul M., Olligs D., Fermon C., Demokritov S.O., Europhys. Lett., 56, (2001); Covington M., Crawford T.M., Parker G.J., Phys. Rev. Lett., 89, (2002); Vlaminck V., Bailleul M., Science, 322, (2008); Zhu M., Dennis C.L., McMichael R.D., Phys. Rev. B, 81, (2010); Sekiguchi K., Yamada K., Seo S.-M., Lee K.-J., Chiba D., Kobayashi K., Ono T., Phys. Rev. Lett., 108, (2012); Yamanoi K., Yakata S., Kimura T., Manago T., Jpn. J. Appl. Phys., 52, (2013); Sato N., Sekiguchi K., Nozaki Y., Appl. Phys. Exp., 6, (2013); Manago T., Yamani K., Kasai S., Mitani S., J. Appl. Phys., 117, (2015); Kasahara K., Nakayama M., Ya X., Matsuyama K., Manago T., Jpn. J. Appl. Phys., 56, (2017); Shibata K., Kasahara K., Nakayama K., Kruglyak V.V., Aziz M.M., Manago T., J. Appl. Phys., 124, (2018); Barman A., Sinha S., Spin Dynamics and Damping in Ferromagnetic Thin Film and Nanostructures, (2018); Ota M., Yamanoi K., Kasai S., Mitani S., Manago T., Jpn. J. Appl. Phys., 54, (2015); Ament W.S., Rado G.T., Phys. Rev., 97, (1955); Almeida N.S., Mills D.L., Phys. Rev. B, 53, (1996); Maksymov I.S., Kostylev M., J. Phys. D Appl. Phys., 46, (2013); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Mayadas A.F., Janak J.F., Gangulee A., J. Appl. Phys., 45, (1974); Vlaminck V., Bailleul M., Phys. Rev. B, 81, (2010); Dvornik M., Au Y., Kruglyak V.V., Magnonics, Topics in Applied Physics, 125, (2013); Stancil D.D., Prabhakar A., Spin Waves - Theory and Applications, (2009); Magni A., Bertotti G., Mayergoyz I.D., Serpico C., Physica B, 306, (2001); Martinez E., Lopez-Diaz L., Torres L., J. Appl. Phys., 99, (2006)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-85070070075" +"Jin M.H.; Zhou N.J.; Xiong L.; Zheng B.","Jin, M.H. (59101751300); Zhou, N.J. (35263424300); Xiong, L. (57209131436); Zheng, B. (57192675807)","59101751300; 35263424300; 57209131436; 57192675807","Depinning phase transitions of current- And field-driven domain wall motion","2019","Journal of Statistical Mechanics: Theory and Experiment","2019","5","53303","","","","4","10.1088/1742-5468/ab190b","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85069494436&doi=10.1088%2f1742-5468%2fab190b&partnerID=40&md5=dbee93d3188cbfef5e4c7f9d731644ec","Department of Physics, Zhejiang University, Hangzhou, 310027, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China; Department of Physics, Hangzhou Normal University, Hangzhou, 310036, China","Jin M.H., Department of Physics, Zhejiang University, Hangzhou, 310027, China, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China; Zhou N.J., Department of Physics, Hangzhou Normal University, Hangzhou, 310036, China; Xiong L., Department of Physics, Zhejiang University, Hangzhou, 310027, China, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China; Zheng B., Department of Physics, Zhejiang University, Hangzhou, 310027, China, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China","With the Landau-Lifshitz-Gilbert (LLG) equation, we investigate critical dynamic behaviors of the domain wall driven by the electric current and the magnetic field in disordered magnetic films. Based on the dynamic scaling form far from stationary, the critical points, and both the static and dynamic exponents of the depinning phase transition are accurately determined. The phase diagram is comprehensively depicted, which agrees with and goes beyond that of the experiments. The adiabatic and non-adiabatic spin-transfer torques induced by the electric current play distinct roles in the depinning phase transition. The novel dynamic approach to the numerical simulations of the LLG equation shows its great efficiency. © 2019 IOP Publishing Ltd and SISSA Medialab srl.","Classical phase transitions; Dynamical processes; Interfaces in random media; Numerical simulations","","","","","","National Natural Science Foundation of China, NSFC, (11375149, 11775186, 11875120); National Natural Science Foundation of China, NSFC; Natural Science Foundation of Zhejiang Province, (LY17A050002); Natural Science Foundation of Zhejiang Province","This work was supported in part by National Natural Science Foundation of China under Grant Nos. 11775186, 11875120, 11375149, and Zhejiang Provincial Natural Science Foundation under Grant No. LY17A050002.","Parkin S., Hayashi M., Thomas L., Science, 320, (2008); Krause S., Herzog G., Stapelfeldt T., Berbil-Bautista L.B., Bode M., Vedmedenko E.Y., Wiesendanger R., Phys. Rev. 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B, 96, (2017); Diaz S.A., Reichhardt C., Arovas D.P., Saxena A., Reichhardt C.J.O., Phys. Rev. Lett., 120, (2018); Grassberger P., Phys. Rev. Lett., 120, (2018); Grassberger P., Dhar D., Mohanty P.K., Phys. Rev. e, 94, (2016); Zhou N.J., Zheng B., He Y.Y., Phys. Rev. B, 80, (2009); Bustingorry S., Kolton A.B., Giamarchi T., Europhys. Lett., 81, (2008); Kolton A.B., Schehr G., Le Doussal P., Phys. Rev. Lett., 103, (2009); Bustingorry S., Kolton A.B., Giamarchi T., Phys. Rev. e, 85, (2012); Ferrero E.E., Bustingorry S., Kolton A.B., Phys. Rev. e, 87, (2013); Purrello V.H., Iguain J.L., Kolton A.B., Jagla E.A., Phys. Rev. e, 96, (2017); Zhou N.J., Zheng B., Phys. Rev. e, 82, (2010); Qin X.P., Zheng B., Zhou N.J., J. Phys. A: Math. Theor., 45, (2012); Zhou N.J., Zheng B., Dai J.H., Phys. Rev. e, 87, (2013)","","","Institute of Physics Publishing","","","","","","17425468","","","","English","J. Stat. Mech. Theory Exp.","Article","Final","","Scopus","2-s2.0-85069494436" +"Choi M.; Lee S.; Kim J.","Choi, Moosung (56438500800); Lee, Sounghun (57194714956); Kim, Jongryoul (58166414700)","56438500800; 57194714956; 58166414700","Clustering Effect on the Frequency-Dependent Magnetic Properties of Fe-Co Micro Hollow Fiber Composites","2017","IEEE Transactions on Magnetics","53","11","7954703","","","","6","10.1109/TMAG.2017.2718181","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85021780178&doi=10.1109%2fTMAG.2017.2718181&partnerID=40&md5=b1176019510e8f2ebb8b557f180f857e","Department of Material Engineering, Hanyang University, Ansan, 15588, South Korea","Choi M., Department of Material Engineering, Hanyang University, Ansan, 15588, South Korea; Lee S., Department of Material Engineering, Hanyang University, Ansan, 15588, South Korea; Kim J., Department of Material Engineering, Hanyang University, Ansan, 15588, South Korea","Composite sheets including Fe-Co magnetic hollow fibers are applicable to near-field electromagnetic wave absorption sheets operating in excess of 1 GHz. To understand the frequency-dependent permeability behavior of composite sheets, the Landau-Lifshitz-Gilbert equation and effective medium theory which are including the effects of the eddy current losses of isolated fibers and magnetostatic correction in high volume fractions can be used. However, the simulation considering only these factors requires a very high damping factor to explain the measured results. Thus, the simulation also needs the consideration of the clustering effect of particles causing the additional eddy current losses. In this paper, a new simulation method for magnetic sheets with clustered particles is proposed to improve an understanding of changes in the high-frequency properties of magnetic composite sheets due to the clustering effect. © 1965-2012 IEEE.","Clustering effect; Landau-Lifshitz-Gilbert (LLG) equation; magnetic permeability; soft magnetic composite","Binary alloys; Cobalt alloys; Iron alloys; Magnetic permeability; Magnetism; Clustering effect; Effective medium theories; Frequency dependent; High volume fraction; High-frequency properties; LLG equation; Magnetic composites; Soft magnetic composites; Cobalt compounds","","","","","Amotech Corporation; Human Resources Development Program of the; Research and Development Program of MOTIE/KEIT, (10043829); Ministry of Trade, Industry and Energy, MOTIE; Korea Institute of Energy Technology Evaluation and Planning, KETEP, (20154030200680); Korea Institute of Energy Technology Evaluation and Planning, KETEP","Funding text 1: ACKNOWLEDGMENT This work was supported in part by the Research and Development Program of MOTIE/KEIT under Grant No. 10043829 and in part by the Human Resources Development Program of the KETEP under Grant No. 20154030200680 funded by Ministry of Trade, Industry and Energy, South Korea. The authors would like to thank Amotech Corporation for assistance with experiment.; Funding text 2: This work was supported in part by the Research and Development Program of MOTIE/KEIT under Grant No. 10043829 and in part by the Human Resources Development Program of the KETEP under Grant No. 20154030200680 funded by Ministry of Trade, Industry and Energy, South Korea. The authors would like to thank Amotech Corporation for assistance with experiment.","Idris F.M., Hashim M., Abbas Z., Ismail I., Nazlan R., Ibrahim I.R., Recent developments of smart electromagnetic absorbers based polymer-composites at gigahertz frequencies, J. Magn. Magn. Mater, 405, pp. 197-208, (2016); Yi J.W., Lee S.B., Kim J.B., Lee S.K., Kim K.H., Park O.O., Evaluation of composites containing hollow Ni/Fe-Co fibers on nearfield electromagnetic wave absorbing properties, Adv. Mater. Res., Vols, 123-125, pp. 1223-1226, (2010); Cho S., Et al., Electro-magnetic properties of composites with aligned Fe-Co hollow fibers, AIP Adv, 6, 5, (2016); Choi M., Choi D., Kim J., Magnetic permeability behaviors of FeCo micro hollow fiber composites, Electron. Mater. Lett, 11, 5, pp. 782-787, (2015); Grimes C.A., Grimes D.M., Permeability and permittivity spectra of granular materials, Phys. Rev. B, Condens. Matter, 43, 13, (1991); Pozar D.M., Microwave Engineering 4th Ed, pp. 452-465, (2012); Jung H.S., Doyle W.D., Matsunuma S., Influence of underlayers on the soft properties of high magnetization FeCo films, J. Appl. Phys, 93, 10, pp. 6462-6464, (2003); Yang Y., Yang Y., Xiao W., Neo C.P., Ding J., Shapedependent microwave permeability of Fe3O4 nanoparticles: A combined experimental and theoretical study, Nanotechnology, 26, 26, (2015); Sihvola A., Electromagnetic Mixing Formulae and Applications (IEEE Electromagnetic Waves Series), 47, pp. 161-163, (1999); Garboczi E.J., Snyder K.A., Thorpe M.F., Douglas J.F., Geometrical percolation threshold of overlapping ellipsoids, Phys. Rev. E, Stat. Phys. Plasmas Fluids Relat. Interdiscip. Top, 52, 1, pp. 819-827, (1995); Christensen K., Percolation Theory, (2002); Ramprasad R., Zurcher P., Petras M., Miller M., Renaud P., Magnetic properties of metallic ferromagnetic nanoparticle composites, J. Appl. Phys, 96, 1, (2004); Yi Y.-B., Wang C.-W., Sastry A.M., Two-dimensional vs. Threedimensional clustering and percolation in fields of overlapping ellipsoids, J. Electrochem. Soc, 151, 8, pp. A1292-A1300, (2004); Wang Y., Hooper I., Edwards E., Grant P.S., Gap-corrected thin-film permittivity and permeability measurement with a broadband coaxial line technique, IEEE Trans. Microw. Theory Techn, 64, 3, pp. 924-930, (2016); Tsutaoka T., Frequency dispersion of complex permeability in Mn-Zn and Ni-Zn spinel ferrites and their composite materials, J. Appl. Phys, 93, 5, pp. 2789-2796, (2003)","J. Kim; Department of Material Engineering, Hanyang University, Ansan, 15588, South Korea; email: jina@hanyang.ac.kr","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85021780178" +"Chen J.; Peng Y.; Zhou J.","Chen, Ji (56687961100); Peng, Yingzi (7403419324); Zhou, Jie (57193515911)","56687961100; 7403419324; 57193515911","Current-induced Rashba spin orbit torque in silicene","2017","Journal of Magnetism and Magnetic Materials","432","","","554","558","4","6","10.1016/j.jmmm.2017.02.043","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85014458454&doi=10.1016%2fj.jmmm.2017.02.043&partnerID=40&md5=194894041ec7a3129fc3173e98453eaa","Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Center for Integrated Spintronic Devices, Hangzhou Dianzi University, Hangzhou, 310018, China","Chen J., Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; Peng Y., Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China, Center for Integrated Spintronic Devices, Hangzhou Dianzi University, Hangzhou, 310018, China; Zhou J., Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China","We study theoretically the spin torque of a ferromagnetic layer coupled to a silicene in the presence of the intrinsic Rashba spin orbit coupling (RSOC) effect. By using gauge field method, we find that under the applied current, the RSOC can induce an effective field which will result in the spin precession of conduction electron without applying any magnetic field. We also derive the spin torques due to the RSOC, which generalize the Landau-Lifshitz-Gilbert (LLG) equation. The spin torques are related to the applied current, the carrier density and Rashba strength of the system. © 2017 Elsevier B.V.","","Magnetic materials; Magnetism; Applied current; Conduction electrons; Effective field; Ferromagnetic layers; Gauge fields; Landau-Lifshitz-Gilbert equations; Rashba spin-orbit coupling; Spin precession; Torque","","","","","National Natural Science Foundation of China, NSFC, (51401069); Natural Science Foundation of Zhejiang Province, (LY16F040003)","This work was supported by the National Natural Science Foundation of China (Grant No. 51401069) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LY16F040003). We thank Yuan Li and Haixia Da for their kind help.","Das Sarma S., Adam S., Hwang E.H., Rossi E., Rev. Mod. Phys., 83, (2011); Tombros N., Jozsa C., Popinciuc M., Jonkman H.T., Wees B.J.V., Nature, 448, (2007); Feng B., Ding Z., Meng S., Yao Y., He X., Cheng P., Chen L., Wu K., Nano. Lett., 12, (2012); Vogt P., De Padova P., Quaresima C., Avila J., Frantzeskakis E., Asensio M.C., Resta A., Ealet B., Le Lay G., Phys. Rev. Lett., 108, (2012); Fleurence A., Friedlein R., Ozaki T., Kawai H., Wang Y., Takamura Y., Phys. Rev. Lett, 108, (2012); Meng L., Wang Y., Zhang L., Du S., Wu R., Li L., Zhang Y., Li G., Zhou H., Hofer W.A., Gao H.J., Nano. Lett, 13, (2013); Chiappe D., Grazianetti C., Tallarida G., Fanciulli M., Houssa A., Molle A., Adv. Mater, 26, (2013); Motohiko E., J. Phys. Soc. Jpn., 84, (2015); Liu C.C., Jiang H., Yao Y.G., Phys. Rev. B, 84, (2011); Dedkov Y.S., Fonin M., Rudiger U., Laubschat C., Phys. Rev. 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Mat., 12, (2013); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.P., Prejbeanu-Buda L., Nat. Mater, 6, (2007); Ezawa M., Phys. Rev. Lett., 109, (2012); Fujita T., Jalil M.B.A., Tan S.G., Murakami S., J. Appl. phys, 110, (2011); Chen J., Jalil M.B.A., Tan S.G., J. Phys. Soc. Jpn., 83, (2013); Iyanaga M., J. Math. Phys., 22, (1981); Yang C.N., Mills R.L., Phys. Rev., 96, (1954); Chen J., Jalil M.B.A., Tan S.G., Aip. Adv., 3, (2013); Tan S.G., Jalil M.B.A., Liu X.J., Fujita T., Phys. Rev. B, 78, (2008); Jalil M.B.A., Tan S.G., IEEE. Trans. Magn, 46, (2010); Aharoni A., Introduction to the Theory of Ferromagnetism, (2000); Bazaliy Y.B., Jones B.A., Zhang S.C., Phys. Rev. B, 57, (1998)","J. Chen; Department of Mathematics, School of Science, Hangzhou Dianzi University, Hangzhou, 310018, China; email: muze7777@hdu.edu.cn","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-85014458454" +"Wysin G.M.","Wysin, G.M. (6701324945)","6701324945","Vortex dynamics in thin elliptic ferromagnetic nanodisks","2015","Fizika Nizkikh Temperatur","41","10","","1009","1023","14","7","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84941759609&partnerID=40&md5=30bbc5a6c3330d79dd1cfb8bdacef90c","Department of Physics, Kansas State University, Manhattan, 66506-2601, KS, United States","Wysin G.M., Department of Physics, Kansas State University, Manhattan, 66506-2601, KS, United States","Vortex gyrotropic motion in thin ferromagnetic nanodisks of elliptical shape is described here for a pure vortex state and for a situation with thermal fluctuations. The system is analyzed using numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equations, including the demagnetization field calculated with a Green's function approach for thin film problems. At finite temperature the thermalized dynamics is found using a second order Heun algorithm for a magnetic Langevin equation based on the LLG equations. The vortex state is stable only within a limited range of ellipticity, outside of which a quasi-single-domain becomes the prefered minimum energy state. A vortex is found to move in an elliptical potential, whose force constants along the principal axes are determined numerically. The eccentricity of vortex motion is directly related to the force constants. Elliptical vortex motion is produced spontaneously by thermal fluctuations. The vortex position and velocity distributions in thermal equilibrium are Boltzmann distributions. The results show that vortex motion in elliptical disks can be described by a Thiele equation. © G.M. Wysin, 2015.","Demagnetization; Dipolar field; Magnetics; Nanoparticles; Vortex dynamics","Aerodynamics; Boltzmann equation; Demagnetization; Differential equations; Ferromagnetic materials; Ferromagnetism; Magnetic nanoparticles; Nanoparticles; Boltzmann distribution; Demagnetization fields; Dipolar fields; Green's function approaches; Landau-Lifshitz-Gilbert equations; Magnetics; Thermal equilibriums; Vortex dynamics; Vortex flow","","","","","","","Usov N.A., Peschany S.E., J. Magn. Magn. Mater, 118, (1993); Raabe J., Pulwey R., Sattler S., Schweinbock T., Zweck J., Weiss D., J. Appl. Phys., 88, (2000); Kasai S., Nakatani Y., Kobayashi K., Kohno H., Ono T., Phys. Rev. Lett., 97, (2006); Pribiag V.S., Krivorotov I.N., Fuchs G.D., Braganca P.M., Ozatay O., Sankey J.C., Ralph D.C., Buhrman R.A., Nature Phys, 3, (2007); Guslienko K.Yu., Lee K.-S., Kim S.-K., Phys. Rev. Lett., 100, (2008); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. 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Phys. Lett., 95, (2004); Garcia-Cervera C.J., Magnetic Domains and Magnetic Domain Walls, (1999); Garcia-Cervera C.J., Gimbutas Z., Weinan E., J. Comp. Phys. E, 184, (2003); Machado T.S., Rappoport T.G., Sampaio L.C., Appl. Phys. Lett., 100, (2012); Gioia G., James R.D., Proc. R. Soc. London Ser. A, 453, (1997); Huang Z., J. Comp. Math., 21, 1, (2003); Suessa D., Fidler J., Schrefl T., Handbook Magn. Mater, 16, (2006); Sasaki J., Matsubara F., J. Phys. Soc. Jpn, 66, (1997); Landau L.D., Lifshitz E.M., Phys. Z. Sowjet, 8, (1935); De Leeuw F.H., Van Den Poel R., Enz U., Rep. Prog. Phys., 43, (1980); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Nowak U., Annual Reviews of Computational Physics IX, (2000); Marsaglia G., Zaman A., Comp. Phys., 8, 1, (1994); Wysin G.M., Phys. Rev. B, 54, (1996); Ivanov B.A., Galkina E.G., Galkin A.Yu., Fiz. Nizk. Temp., 36, (2010); Low Temp. Phys., 36, (2010); Zaspel C.E., Wysin G.M., Phys. Rev. B, 90, (2014)","G.M. Wysin; Department of Physics, Kansas State University, Manhattan, 66506-2601, United States; email: wysin@phys.ksu.edu","","B.Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine","","","","","","01326414","","FNTED","","English","Fiz Nizk Temp","Article","Final","","Scopus","2-s2.0-84941759609" +"Ayouch C.; Essoufi El-H.; Tilioua M.","Ayouch, C. (57189905298); Essoufi, El-H. (6504162169); Tilioua, M. (6507877823)","57189905298; 6504162169; 6507877823","On a non-scalar damping model in micromagnetism","2018","International Journal of Dynamical Systems and Differential Equations","8","1-2","","6","18","12","0","10.1504/IJDSDE.2018.089091","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85115870904&doi=10.1504%2fIJDSDE.2018.089091&partnerID=40&md5=d1b1ca4f0656735661e78c301232d263","Laboratoire MISI, FST Settat, University Hassan i, Settat, 26000, Morocco; M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","Ayouch C., Laboratoire MISI, FST Settat, University Hassan i, Settat, 26000, Morocco; Essoufi El-H., Laboratoire MISI, FST Settat, University Hassan i, Settat, 26000, Morocco; Tilioua M., M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, P.O. Box 509, Boutalamine, Errachidia, 52000, Morocco","We consider a mathematical model describing magnetisation dynamics with non-scalar damping. The model consists on a generalised Landau-Lifshitz-Gilbert equation with a general damping tensor. We apply Faedo-Galerkin/penalty method to show the existence of global weak solutions in one-dimensional case. Copyright © 2018 Inderscience Enterprises Ltd.","Faedo-Galerkin method; Ferromagnetic materials; Global existence; LLG equation","Damping; Galerkin methods; Damping modelings; Faedo-galerkin method; Global existence; Global weak solution; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetization dynamics; Micromagnetisms; One-dimensional; Penalty methods; Ferromagnetic materials","","","","","Providence Health Care, PHC, (MA/14/301); Ministry of Higher Education and Scientific Research, MHESR; Ministère des Affaires Etrangères","The research is supported by the PHC Volubilis program MA/14/301 “Elaboration et analyse de modèles asymptotiques en micro-magnétisme, magnéto-élasticité et électro-élasticité” with joint financial support from the French Ministry of Foreign Affairs and the Moroccan Ministry of Higher Education and Scientific Research.","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and non uniqueness, Nonlinear Analysis, 18, pp. 1071-1084, (1992); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau- Lifshitz-Gilbert equation, SIAM Journal on Numerical Analysis, 44, pp. 1405-1419, (2006); Baryakthar V. G., Ivanov B. A., Sukstanskii A. L., . Melikhov E., Soliton relaxation in magnets, Physical Review B, 56, pp. 619-635; Bertsch M., Podio-Guidugli P., Valente V., On the dynamics of deformable ferromagnets. I. Global weak solutions for soft ferromagnets at rest, Annali di Matematica Pura ed Applicata, 179, 4, pp. 331-360; Carbou G., Fabrie P., Time average in micromagnetism, The Journal of Differential Equations, 147, pp. 383-409; Gilbert T. L., A phenomenological theory of damping in ferromagnetic materials, IEEE Transactions on Magnetics, 40, (2004); Guo B., Hong M.C., The Landau-Lifshitz equation of the ferromagetic spin chain and harmonic maps, Calculus of Variations and Partial Differential Equations, 1, pp. 311-334, (1993); Hadda M., Tilioua M., On magnetization dynamics with inertial effects, Journal of Engineering Mathematics, 88, pp. 197-206, (2014); Lions J.L., Quelques Méthodes de Résolution des Problèmes aux Limites Non Linéaires, (1969); Melcher C., Ptashnyk M., Landau-Lifshitz-Slonczewski equations: global weak and classical solutions, The SIAM Journal on Mathematical Analysis, 45, 1, pp. 407-429, (2013); Podio-Guidugli P., On dissipation mechanisms in micromagnetics, The European Physical Journal B, 19, pp. 417-424, (2001); Podio-Guidugli P., Valente V., Existence of global-in-time weak solutions to a modified Gilbert equation, Nonlinear Analysis, 47, pp. 147-158, (2001); Prohl A., Computational Micromagnetism, Advances in Numerical Mathematics, (2001); Rossi E., Heinonen O.G., MacDonald A.H., Dynamics of magnetization coupled to a thermal bath of elastic modes, Physical Review B, 72, (2005); Roubicek T., Tomassetti G., Zanini C., The Gilbert equation with dry-friction type damping, Journal of Mathematical Analysis and Applications, 355, 2, pp. 453-468, (2009); Safonov V.L., Bertram H.N., Fluctuation-dissipation considerations and damping models for ferromagnetic materials, Journal of Applied Physics, 94, (2003); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Applied Numerical Mathematics, 46, 1, pp. 95-111, (2003); Slonczewski J., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, pp. L1-L7, (1996); Tilioua M., Current-induced magnetization dynamics. Global existence of weak solutions, Journal of Mathematical Analysis and Applications, 373, pp. 635-642, (2011); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Japan Journal of Industrial and Applied Mathematics, 2, pp. 69-84, (1985); Weinan E., Wang X.-P., Numerical methods for the Landau-Lifshitz equation, SIAM Journal on Numerical Analysis, 38, 5, pp. 1647-1665, (2000); Zhang S., Zhang S.S-L., Generalization of the Landau-Lifshitz-Gilbert equation for conducting ferromagnets, Physical Review Letters, 102, (2009)","M. Tilioua; M2I Laboratory, MAMCS Group, FST Errachidia, University Moulay Ismaïl, Errachidia, P.O. Box 509, Boutalamine, 52000, Morocco; email: m.tilioua@fste.umi.ac.ma","","Inderscience Publishers","","","","","","17523583","","","","English","Int. J. Dyn. Syst. Differ. Equ.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-85115870904" +"Lee H.; Lee A.; Wang S.; Ebrahimi F.; Gupta P.; Khalili Amiri P.; Wang K.L.","Lee, Hochul (56673167900); Lee, Albert (56564515500); Wang, Shaodi (56520960500); Ebrahimi, Farbod (56890778400); Gupta, Puneet (35422495300); Khalili Amiri, Pedram (9942248300); Wang, Kang L. (7201949295)","56673167900; 56564515500; 56520960500; 56890778400; 35422495300; 9942248300; 7201949295","Analysis and Compact Modeling of Magnetic Tunnel Junctions Utilizing Voltage-Controlled Magnetic Anisotropy","2018","IEEE Transactions on Magnetics","54","4","4400209","","","","34","10.1109/TMAG.2017.2788010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85042348571&doi=10.1109%2fTMAG.2017.2788010&partnerID=40&md5=107230fb44d27345ef0273d7e3c7cafd","Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States; Inston Inc., Los Angeles, 90095, CA, United States","Lee H., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States, Inston Inc., Los Angeles, 90095, CA, United States; Lee A., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States; Wang S., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States; Ebrahimi F., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States, Inston Inc., Los Angeles, 90095, CA, United States; Gupta P., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States; Khalili Amiri P., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States, Inston Inc., Los Angeles, 90095, CA, United States; Wang K.L., Department of Electrical Engineering, University of California, Los Angeles, 90095, CA, United States","A macrospin compact model of a perpendicularly magnetized voltage-controlled magnetic tunnel junction (MTJ) is introduced, for the evaluation of electronic and magnetic characteristics associated with its switching behavior. The voltage-driven precessional switching has been shown to outperform current-driven switching in terms of energy, speed, and bit density. However, to realize the device in embedded system memory applications, developing a compact model for simulating hybrid MTJ/CMOS circuits is necessary. This framework also needs to be compatible with conventional computer-aided circuit design tools and flows. In this paper, the voltage-controlled magnetic anisotropy effect is included as a component of the effective magnetic field in a Landau-Lifshitz-Gilbert (LLG) equation-based model. The compact model is described by Verilog-A, providing a numerical solution for a 3-D magnetization trajectory and the corresponding conductance change of the MTJ. We also include the thermal noise effect in the LLG equation to allow the evaluation of stochastic switching behavior under a wide variety of bias conditions, which can be quantified in terms of write error rate (WER). It is shown that the model allows for optimization of write pulse shape and design considerations to achieve the lowest WER for given MTJ parameters. © 1965-2012 IEEE.","Macrospin compact model; magnetic tunnel junction (MTJ); voltage-controlled magnetic anisotropy (VCMA); write error rate (WER)","Anisotropy; Field effect transistors; Integrated circuit manufacture; Magnetic anisotropy; Magnetism; Stochastic systems; Switching; Thermal noise; Tunnel junctions; Compact model; Current-driven switching; Error rate; Landau-Lifshitz-Gilbert equations; Magnetic characteristic; Magnetic tunnel junction; Precessional switching; Voltage-controlled; Magnetic devices","","","","","ACM/SIGDA; Inston Inc.; National Science Foundation, NSF; International Business Machines Corporation, IBM","Funding text 1: Dr. Gupta was a recipient of the NSF CAREER Award, the ACM/SIGDA Outstanding New Faculty Award, and the IBM Faculty Award.; Funding text 2: ACKNOWLEDGMENT This work was supported by Inston Inc., Santa Monica, CA, USA, through a Phase II Small Business Innovation Research Award from the National Science Foundation.","Ikeda S., Et al., Tunnel magnetoresistance of 604% at 300 K by suppression of Ta diffusion in CoFeB/MgO/CoFeB pseudo-spin-valves annealed at high temperature, Appl. Phys. Lett., 93, 8, (2008); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1-2, pp. L1-L7, (1996); Katine J.A., Fullerton E.E., Device implications of spin-transfer torques, J. Magn. Magn. Mater., 320, 7, pp. 1217-1226, (2008); Amiri P.K., Et al., Low write-energy magnetic tunnel junctions for high-speed spin-transfer-torque MRAM, IEEE Electron Device Lett., 32, 1, pp. 57-59, (2011); Seki T., Et al., Giant spin Hall effect in perpendicularly spin-polarized FePt/Au devices, Nature Mater, 7, 2, pp. 125-129, (2008); Liu L., Pai C.-F., Li Y., Tseng H.W., Ralph D.C., Buhrman R.A., Spin-torque switching with the giant spin Hall effect of tantalum, Science, 336, 6081, pp. 555-558, (2012); Fan Y., Et al., Magnetization switching through giant spin-orbit torque in a magnetically doped topological insulator heterostructure, Nature Mater, 13, 7, pp. 699-704, (2014); Wang K.L., Alzate J.G., Amiri P.K., Low-power non-volatile spintronic memory: STT-RAM and beyond, J. Phys. D. Appl. Phys., 46, 7, (2013); Kanai S., Yamanouchi M., Ikeda S., Nakatani Y., Matsukura F., Ohno H., Electric field-induced magnetization reversal in a perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction, Appl. Phys. Lett, 101, 12, (2012); Alzate J.G., Et al., Voltage-induced switching of nanoscale magnetic tunnel junctions, IEDM Tech. Dig, pp. 2951-2954, (2012); Wang W.-G., Li M., Hageman S., Chien C.L., Electric-field-assisted switching in magnetic tunnel junctions, Nature Mater, 11, 1, pp. 64-68, (2012); Shiota Y., Nozaki T., Bonell F., Murakami S., Shinjo T., Suzuki Y., Induction of coherent magnetization switching in a few atomic layers of FeCo using voltage pulses, Nature Mater, 11, 1, pp. 39-43, (2012); Wang P., Zhang W., Joshi R., Kanj R., Chen Y., A thermal and process variation aware MTJ switching model and its applications in soft error analysis, Proc. Int. Conf. Comput.-Aided Design (ICCAD), pp. 720-727, (2012); Panagopoulos G.D., Augustine C., Roy K., Physics-based SPICE-compatible compact model for simulating hybrid MTJ/CMOS circuits, IEEE Trans. Electron Devices, 60, 9, pp. 2808-2814, (2013); Demin G.D., Gusev E.E., Popkov A.F., Stepanov P.A., Djuzhev N.A., Compact HSPICE model of magnetic tunnel junction based on voltage-driven spin-transfer torque, Proc. Int. Siberian Conf. Control Commun. (SIBCON), pp. 1-6, (2016); Roy A.S., Sarkar A., Mudanai S.P., Compact modeling of magnetic tunneling junctions, IEEE Trans. Electron Devices, 63, 2, pp. 652-658, (2016); Sharmin S., Jaiswal A., Roy K., Modeling and design space exploration for bit-cells based on voltage-assisted switching of magnetic tunnel junctions, IEEE Trans. Electron Devices, 63, 9, pp. 3493-3500, (2016); Kang W., Ran Y., Zhang Y., Lv W., Zhao W., Modeling and exploration of the voltage-controlled magnetic anisotropy effect for the next-generation low-power and high-speed MRAM applications, IEEE Trans. Nanotechnol., 16, 3, pp. 387-395, (2017); Shiota Y., Et al., Evaluation of write error rate for voltage-driven dynamic magnetization switching in magnetic tunnel junctions with perpendicular magnetization, Appl. Phys. Exp., 9, 1, (2016); Grezes C., Et al., Ultra-low switching energy and scaling in electric-field-controlled nanoscale magnetic tunnel junctions with high resistance-area product, Appl. Phys. Lett, 108, 1, (2016); Landau L.D., Lifshits E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. Sow, 8, pp. 153-169, (1935); Ikeda S., Et al., A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction, Nature Mater, 9, 9, pp. 721-724, (2010); Maruyama T., Et al., Large voltage-induced magnetic anisotropy change in a few atomic layers of iron, Nature Nanotechnol, 4, 3, pp. 158-161, (2009); Nozaki T., Shiota Y., Shiraishi M., Shinjo T., Suzuki Y., Voltage-induced perpendicular magnetic anisotropy change in magnetic tunnel junctions, Appl. Phys. Lett, 96, 2, (2010); Nozaki T., Et al., Voltage-induced magnetic anisotropy changes in an ultrathin FeB layer sandwiched between two MgO layers, Appl. Phys. Exp., 6, 7, (2013); Velev J.P., Jaswal S.S., Tsymbal E.Y., Multi-ferroic and mag-netoelectric materials and interfaces, Philos. Trans. Roy. Soc. London A, Math., Phys. Eng. Set, 369, 1948, pp. 3069-3097, (2011); Barnes S.E., Ieda J., Maekawa S., Rashba spin-orbit anisotropy and the electric field control of magnetism, Set Rep., 4, (2014); Sun J.Z., Spin angular momentum transfer in current-perpendicular nanomagnetic junctions, IBM J. Res. Develop., 50, 1, pp. 81-100, (2006); Berkov D.V., Fast switching of magnetic nanoparticles: Simulation of thermal noise effects using the Langevin dynamics, IEEE Trans. Magn., 38, 5, pp. 2489-2495, (2002); Ahmed R., Victora R.H., Possible explanation for observed effectiveness of voltage-controlled anisotropy in CoFeB/MgO MTJ, IEEE Trans. Magn., 51, 11, (2015); Julliere M., Tunneling between ferromagnetic films, Phys. Lett. A, 54, 3, pp. 225-226, (1975); Lee H., Et al., Design of a fast and low-power sense amplifier and writing circuit for high-speed MRAM, IEEE Trans. Magn., 51, 5, (2014); Dorrance R., Et al., Diode-MTJ crossbar memory cell using voltage-induced unipolar switching for high-density MRAM, IEEE Electron Device Lett., 34, 6, pp. 753-755, (2013); Lee H., Et al., Source line sensing in magneto-electric random-access memory to reduce read disturbance and improve sensing margin, IEEE Magn. Lett., 7, (2016); Nowak J.J., Et al., Dependence of voltage and size on write error rates in spin-transfer torque magnetic random-access memory, IEEE Magn. Lett., 7, (2016); Wang S., Hu H.C., Zheng H., Gupta P., MEMRES: A fast memory system reliability simulator, IEEE Trans. Rel., 65, 4, pp. 1783-1797, (2016); Grezes C., Et al., Write error rate and read disturbance in electric-field-controlled magnetic random-access memory, IEEE Magn. Lett., 8, (2016); Noguchi H., Et al., Novel voltage controlled MRAM (VCM) with fast read/write circuits for ultra large last level cache, IEDM Tech. Dig, pp. 2751-2754, (2016); Ikegami K., Et al., MTJ-based 'normally-off processors' with thermal stability factor engineered perpendicular MTJ, L2 cache based on 2T-2MTJ cell, L3 and last level cache based on 1T-1MTJ cell and novel error handling scheme, IEDM Tech. Dig, pp. 2511-2514, (2015)","H. Lee; Department of Electrical Engineering, University of California, Los Angeles, 90095, United States; email: chul0524@ucla.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85042348571" +"Skomski R.; Kashyap A.; Sellmyer D.J.","Skomski, R. (8773824700); Kashyap, A. (35187189600); Sellmyer, D.J. (22976864300)","8773824700; 35187189600; 22976864300","A quantum-mechanical relaxation model","2012","Journal of Applied Physics","111","7","07D507","","","","1","10.1063/1.3679605","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861738400&doi=10.1063%2f1.3679605&partnerID=40&md5=e774ae538dadbb7589fe249f7daf9380","Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, United States; School of Basic Sciences, Indian Institute of Technology Mandi, Himachal Pradesh 175001, India","Skomski R., Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, United States; Kashyap A., School of Basic Sciences, Indian Institute of Technology Mandi, Himachal Pradesh 175001, India; Sellmyer D.J., Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, United States","The atomic origin of micromagnetic damping is investigated by developing and solving a quantum-mechanical relaxation model. A projection-operator technique is used to derive an analytical expression for the relaxation time as a function of the heat-bath and interaction parameters. The present findings are consistent with earlier research beyond the Landau-Lifshitz-Gilbert (LLG) equation and show that the underlying relaxation mechanism is very general. Zermelo's recurrence paradox means that there is no true irreversibility in non-interacting nanoparticles, but the corresponding recurrence times are very long and can be ignored in many cases. © 2012 American Institute of Physics.","","Physical properties; Analytical expressions; Interaction parameters; Landau-Lifshitz-Gilbert equations; Micromagnetics; Quantum mechanical; Recurrence time; Relaxation mechanism; Relaxation models; Physics","","","","","BREM; NCMN; NSF-MRSEC; National Science Foundation, NSF, (0820521); U.S. Department of Energy, USDOE; Department of Science and Technology, Ministry of Science and Technology, India, डीएसटी","Thanks are due to P. Lougovski for discussing decoherence effects in quantum systems. This research is supported by NSF-MRSEC (RS), DOE (DJS), BREM (RS), DST (AK), and NCMN.","Becker R., Dring W., Ferromagnetismus, (1939); Kramers H.A., Physica, 7, (1940); Zwanzig R., Phys. Rev., 124, (1961); Skomski R., Coey J.M.D., Permanent Magnetism, (1999); Weller D., McDaniel T., In Advanced Magnetic Nanostructures, (2006); Nielsen M.A., Chuang I.L., Quantum Computation and Quantum Information, (2000); Zwanzig R., Nonequilibrium Statistical Mechanics, (2001); Starikov A.A., Kelly P.J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 105, (2010); Fhnle M., Illg C., J. Phys.: Condens. Matter, 23, (2011); Kambersky V., Patton C.E., Phys. Rev. B, 11, (1975); Heinrich B., Urban R., Woltersdorf G., IEEE Trans. Magn., 38, 5, (2002); Suhl H., IEEE Trans. Magn., 34, 4, (1998); Skomski R., Zhou J., Sellmyer D.J., J. Appl. Phys., 97, (2005); Skomski R., Simple Models of Magnetism, (2008); Brenig W., Statistical Theory of Heat: Nonequilibrium Phenomena, (1989)","R. Skomski; Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588, United States; email: rskomski@neb.rr.com","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-84861738400" +"Freschi F.; Giaccone L.; Khan O.; Ragusa C.; Repetto M.","Freschi, Fabio (8860381200); Giaccone, Luca (24476072700); Khan, Omar (54999482800); Ragusa, Carlo (6603386642); Repetto, Maurizio (7102465243)","8860381200; 24476072700; 54999482800; 6603386642; 7102465243","Analysis of the circuit-field interactions in propagating spin-wave experiments","2015","IEEE Transactions on Magnetics","51","3","7093538","","","","0","10.1109/TMAG.2014.2360231","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84928818342&doi=10.1109%2fTMAG.2014.2360231&partnerID=40&md5=4c51095e8d00e6fb3763061e7994c6a4","Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; National University of Computer and Emerging Sciences, Peshawar, 54590, Pakistan","Freschi F., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; Giaccone L., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; Khan O., National University of Computer and Emerging Sciences, Peshawar, 54590, Pakistan; Ragusa C., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; Repetto M., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy","In propagating spin-wave experiments, a micrometer-wide inductive antenna excites magnetostatic spin waves in a magnetic thin film. These spin waves propagate along the film and are readout by a second displaced antenna to observe the processed signal. We present a numerical model for describing the interaction between the exciting antenna and magnetic film and eventually present a discussion on the efficiency of the excitation process. Our model is based on coupling the partial element equivalent circuit method - usually applied to the simulation of multiconductor circuits, to the micromagnetic model - based on the linearized Landau-Lifschitz-Gilbert equation representing the magnetic film. The problem involves different geometric dimensions: ranging from the millimeter scale in the supply circuit to the micrometer one for the antenna interacting with the magnetic material. In this paper, we report the study of a possible decoupling between the two scales based on an equivalent circuit of the magnetic phenomenon. © 2015 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnonics; partial element equivalent circuit (PEEC); spin waves","Antennas; Equivalent circuits; Magnetic devices; Magnetic films; Magnetic materials; Magnetic thin films; Magnetism; Magnetostatics; Micrometers; Multilayers; Spin waves; Geometric dimensions; Landau-Lifshitz-Gilbert equations; Magnetic phenomena; Magnetostatic spin waves; magnonics; Micromagnetic modeling; Partial element equivalent circuit; Partial-element equivalent-circuit methods; Electric network analysis","","","","","","","Kruglyak V., Demokritov S., Grundler D., Magnonics, J. Phys. D, Appl. Phys., 43, 26, pp. 264001-264014, (2010); Fallarino L., Et al., Propagation of spin waves excited in a permalloy film by a finite-ground coplanar waveguide: A combined phasesensitive micro-focused Brillouin light scattering and micromagnetic study, IEEE Trans. Magn., 49, 3, pp. 1033-1036, (2013); Freschi F., Giaccone L., Khan O.U., Ragusa C., Repetto M., Coupling spin waves to circuits through PEEC approach, Proc. 9th IET Int. Conf. Comput. Electromagn. (CEM), pp. 1-2, (2014); Ruehli A.E., Equivalent circuit models for three-dimensional multiconductor systems, IEEE Trans. Microw. Theory Techn., 22, 3, pp. 216-221, (1974); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Khan O., Ragusa C., Khan F., Montrucchio B., A mutual demagnetizing tensor for n-body magnetic field modeling, IEEE Trans. Magn., 49, 7, pp. 3179-3182, (2013); Freschi F., Repetto M., A general framework for mixed structured/unstructured PEEC modelling, Appl. Comput. Electromagn. Soc. J., 23, 3, pp. 200-206, (2008)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84928818342" +"Celegato F.; Coisson M.; Khan O.; Kuepferling M.; Magni A.; Ragusa C.; Rahim A.; Portesi C.; Wang W.","Celegato, Federica (16033291100); Coisson, Marco (56245973100); Khan, Omar (54999482800); Kuepferling, Michaela (24070987200); Magni, Alessandro (7007060492); Ragusa, Carlo (6603386642); Rahim, Arbab (37089170900); Portesi, Chiara (56461147400); Wang, Wencui (55369007900)","16033291100; 56245973100; 54999482800; 24070987200; 7007060492; 6603386642; 37089170900; 56461147400; 55369007900","Comprehensive theoretical and experimental analysis of spin waves in magnetic thin film","2015","IEEE Transactions on Magnetics","51","1","7029190","","","","2","10.1109/TMAG.2014.2360317","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84922747070&doi=10.1109%2fTMAG.2014.2360317&partnerID=40&md5=1663dbce903c73f97e431ac1c16ce4d5","Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; National University of Computer and Emerging Sciences, Peshawar, 54590, Pakistan","Celegato F., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Coisson M., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Khan O., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy, National University of Computer and Emerging Sciences, Peshawar, 54590, Pakistan; Kuepferling M., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Magni A., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Ragusa C., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; Rahim A., Dipartimento Energia, Politecnico di Torino, Turin, 10129, Italy; Portesi C., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Wang W., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy","Magnetic spin waves (SWs) have been induced and detected in a Ni80Fe20 thin film by two identical copper coplanar waveguides (CPWs). The dc fields up to 25 kA/m have been applied parallel to the CPWs, and magnetostatic surface SWs have been generated by applying voltages through the first CPW (source). The second CPW (pickup), 12 μ m apart from the source, has been used to detect the ensuing SWs. Two independent setup and methods have been applied. Time domain SW measurements were performed by the application of voltage steps and the ensuing SW signal has been measured using a 16 GHz oscilloscope. Frequency domain SW spectroscopy was performed using a two-port vector network analyzer measurement in a frequency range from 10 MHz to 10 GHz. In addition, micromagnetic simulations were performed under the harmonic regime by assuming the induced SWs as perturbations of the saturated ground state excited by a small RF field. The numerically computed dispersion relation closely follows the Damon-Eshbach curve and is in good agreement with the experimental data. © 1965-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnonics; spin waves (SWs)","Dispersions; Electric network analyzers; Excited states; Frequency domain analysis; Ground state; Magnetic thin films; Multilayers; Spin waves; Thin films; Time domain analysis; Dispersion relations; Experimental analysis; Frequency domains; Frequency ranges; Landau-Lifshitz-Gilbert equations; magnonics; Micromagnetic simulations; Vector network analyzers; Coplanar waveguides","","","","","","","Kwon J.H., Mukherjee S.S., Deorani P., Hayashi M., Yang H., Characterization of magnetostatic surface spin waves in magnetic thin films: Evaluation for microelectronic applications, Appl. Phys. A, 111, 2, pp. 369-378, (2013); Kruglyak V.V., Demokritov S.O., Grundler D., Magnonics, J. Phys. D, Appl. Phys., 43, 26, (2010); Fassbender J., Magnetization dynamics investigated by time-resolved Kerr effect magnetometry, Spin Dynamics in Confined Magnetic Structures, 2, (2003); Stancil D.D., Prabhakar A., Spin Waves: Theory and Applications, (2009); Patton C.E., Magnetic excitations in solids, Phys. Rep., 103, 5, pp. 251-315, (1984); Sato N., Ishida N., Kawakami T., Sekiguchi K., Propagating spectroscopy of backward volume spin waves in a metallic FeNi film, Appl. Phys. Lett., 104, 3, (2014); Covington M., Crawford T.M., Parker G.J., Time-resolved measurement of propagating spin waves in ferromagnetic thin films, Phys. Rev. Lett., 89, (2002); Liu Z., Giesen F., Zhu X., Sydora R.D., Freeman M.R., Spin wave dynamics and the determination of intrinsic damping in locally excited permalloy thin films, Phys. Rev. Lett., 98, (2007); Sekiguchi K., Et al., Nonreciprocal emission of spin-wave packet in FeNi film, Appl. Phys. Lett., 97, 2, (2010); Bailleul M., Olligs D., Fermon C., Demokritov S.O., Spin waves propagation and confinement in conducting films at the micrometer scale, Europhys. Lett., 56, 5, (2001); Bailleul M., Olligs D., Fermon C., Propagating spin wave spectroscopy in a permalloy film: A quantitative analysis, Appl. Phys. Lett., 83, 5, (2003); Vlaminck V., Bailleul M., Spin-wave transduction at the submicrometer scale: Experiment and modeling, Phys. Rev. B, 81, (2010); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems (Electromagnetism), (2009); Khan O., Ragusa C., Khan F., Montrucchio B., A mutual demagnetizing tensor for N-body magnetic field modeling, IEEE Trans. Magn., 49, 7, pp. 3179-3182, (2013); Magni A., Bottauscio O., Caprile A., Celegato F., Ferrara E., Fiorillo F., Spin precession by pulsed inductive magnetometry in thin amorphous plates, J. Appl. Phys., 115, 17, (2014); Yamanoi K., Yakata S., Kimura T., Manago T., Spin wave excitation and propagation properties in a permalloy film, Jpn. J. Appl. Phys., 53, 8 R, (2013); Fallarino L., Et al., Propagation of spin waves excited in a permalloy film by a finite-ground coplanar waveguide: A combined phase-sensitive micro-focused Brillouin light scattering and micromagnetic study, IEEE Trans. Magn., 49, 3, pp. 1033-1036, (2013); Neusser S., Spin Waves in Antidot Lattices: From Quantization to Magnonic Crystals, (2011); Neudecker I., Woltersdorf G., Heinrich B., Okuno T., Gubbiotti G., Back C.H., Comparison of frequency, field, and time domain ferromagnetic resonance methods, J. Magn. Magn. Mater., 307, 1, pp. 148-156, (2006)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84922747070" +"Bian Q.; Niewczas M.","Bian, Q. (56287571600); Niewczas, M. (7003753114)","56287571600; 7003753114","Model of the magnetization of nanocrystalline materials at low temperatures","2014","Journal of Applied Physics","116","3","033921","","","","4","10.1063/1.4890615","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84904689561&doi=10.1063%2f1.4890615&partnerID=40&md5=aa07fae828c2c3495a3e13ac28d6c7ed","Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S4M1, Canada","Bian Q., Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S4M1, Canada; Niewczas M., Department of Materials Science and Engineering, McMaster University, Hamilton, ON L8S4M1, Canada","A theoretical model incorporating the material texture has been developed to simulate the magnetic properties of nanocrystalline materials at low temperatures where the effect of thermal energy on magnetization is neglected. The method is based on Landau-Lifshitz-Gilbert (LLG) theory and it describes the magnetization dynamics of individual grains in the effective field. The modified LLG equation incorporates the intrinsic fields from the intragrain magnetocrystalline and grain boundary anisotropies and the interacting fields from intergrain dipolar and exchange couplings between the neighbouring grains. The model is applied to study magnetic properties of textured nanocrystalline Ni samples at 2K and is capable to reproduce closely the hysteresis loop behaviour at different orientations of applied magnetic field. Nanocrystalline Ni shows the grain boundary anisotropy constant K 1 s = - 6.0 × 10 4 J / m 3 and the intergrain exchange coupling denoted by the effective exchange constant Ap = 2.16 × 10-11 J/m. Analytical expressions to estimate the intergrain exchange energy density and the effective exchange constant have been formulated. © 2014 AIP Publishing LLC.","","Anisotropy; Grain boundaries; Low temperature engineering; Magnetic properties; Magnetization; Nickel; Strength of materials; Analytical expressions; Applied magnetic fields; Grain boundary anisotropy; Intergrain exchange; Intergrain exchange coupling; Landau-Lifshitz-Gilbert; Magnetization dynamics; Theoretical modeling; Nanocrystalline materials","","","","","","","Datta S., Das B., Appl. Phys. Lett., 56, (1990); Kiselev S.I., Sankey J.C., Krivotorov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Raph D.C., Nature, 425, (2003); Gallagher W.J., Parkin S.S.P., IBM J. Res. Dev., 50, (2006); Huang B., Monsma D., Appelbaum B., Appl. Phys. Lett., 91, (2007); Tjong S.C., Chen H., Mater. Sci. Eng. R, 45, (2004); Suryanarayana C., Koch C.C., Hyperfine Interact., 130, (2000); Gleiter H., Prog. Mater. 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Phys., 87, (2000)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-84904689561" +"Shepherd D.; Miles J.; Heil M.; Mihajlovic M.","Shepherd, David (56440967400); Miles, Jim (55432704000); Heil, Matthias (35553360100); Mihajlovic, Milan (15822349100)","56440967400; 55432704000; 35553360100; 15822349100","Discretization-induced stiffness in micromagnetic simulations","2014","IEEE Transactions on Magnetics","50","11","6971771","","","","6","10.1109/TMAG.2014.2325494","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84916195957&doi=10.1109%2fTMAG.2014.2325494&partnerID=40&md5=9745f89aea0b9dfa1b72171fb2752e63","School of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom; School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom","Shepherd D., School of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom; Miles J., School of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom; Heil M., School of Mathematics, University of Manchester, Manchester, M13 9PL, United Kingdom; Mihajlovic M., School of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom","In the numerical integration of the Landau-Lifshitz-Gilbert (LLG) equation, stiffness (stability restrictions on the time step size for explicit methods) is known to be a problem in some cases. We examine the relationship between stiffness and spatial discretization size for the LLG with exchange and magnetostatic effective fields. A maximum stable time step is found for the reversal of a single-domain spherical nanoparticle with a variety of magnetic parameters and numerical methods. From the lack of stiffness when solving a physically equivalent ODE problem, we conclude that any stability restrictions in the partial differential equation case arise from the spatial discretization rather than the underlying physics. We find that the discretization-induced stiffness increases as the mesh is refined and the damping parameter is decreased. In addition, we find that the use of the FEM/BEM method for magnetostatic calculations increases the stiffness. Finally, we observe that the use of explicit magnetostatic calculations within an otherwise implicit time integration scheme (i.e. a semi-implicit scheme) does not cause stability issues. © 1965-2012 IEEE.","Micromagnetics; numerical stability","Convergence of numerical methods; Differential equations; Magnetostatics; Nanomagnetics; Stability; Stiffness; Implicit time integration; Landau-Lifshitz-Gilbert equations; Magnetostatic calculations; Micromagnetic simulations; Micromagnetics; Numerical integrations; Spatial discretizations; Spherical nanoparticles; Numerical methods","","","","","Engineering and Physical Sciences Research Council, (EP/G01705/1)","","Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the Landau-Lifshiftz-Gilbert equation for micromagnetics, Jpn. J. Appl. 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Phys, 209, 2, pp. 730-753, (2005); HYPRE-High Performance Preconditioning Library; Heil M., Hazel A., Oomph-Lib; Shepherd D., Oomph-Lib-Micromagnetics, (2014); Hubert A., Schafer R., Magnetic Domains, (1998); Mallinson J.C., Damped gyromagnetic switching, IEEE Trans. Magn, 36, 4, pp. 1976-1981, (2000); Si H., Tetgen: A Quality Tetrahedral Mesh Generator and A 3D Delaunay Triangulator, (2013); Fangohr H., Et al., NMAG User Manual, (2012); Suess D., Et al., Time resolved micromagnetics using a preconditioned time integration method, J. Magn. Magn. Mater, 248, 2, pp. 298-311, (2002); Andreas C., Gliga S., Hertel R., Numerical micromagnetism of strong inhomogeneities, J. Magn. Magn. Mater, 362, pp. 7-13, (2014); McMichael B., μmAG-Micromagnetic Modeling Activity Group","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84916195957" +"Jing Z.; Yong H.; Zhou Y.-H.","Jing, Ze (55353008100); Yong, Huadong (16030102800); Zhou, You-He (35276608800)","55353008100; 16030102800; 35276608800","Vortex structures and magnetic domain patterns in the superconductor/ferromagnet hybrid bilayer","2014","Superconductor Science and Technology","27","10","105005","","","","8","10.1088/0953-2048/27/10/105005","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84907211017&doi=10.1088%2f0953-2048%2f27%2f10%2f105005&partnerID=40&md5=7b8299a5c7e6d151c1a9068188be3a0c","Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, 730000, China","Jing Z., Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, 730000, China; Yong H., Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, 730000, China; Zhou Y.-H., Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, 730000, China","Superconducting vortices and magnetic domain patterns' evolution in the superconductor-ferromagnet (SC/FM) hybrid bilayer are investigated within the Ginzburg - Landau (GL) theory of superconductivity, in combination with the Landau - Lifshitz - Gilbert (LLG) equation of ferromagnetism. Magnetic domain patterns in the ferromagnetic thin film and the vortices' nucleation in the superconducting layer for the hybrid bilayer, subjected to perpendicular magnetic fields, are obtained by numerical simulations. A dynamical evolution picture of the magnetic domain patterns and the associated superconducting vortices' nucleation are clearly shown. The effect of geometry parameters and physical parameters on the magnetic domain and superconducting vortex evolution are discussed. The magnetization curve of the SC film has also been illustrated. We found that the vortex dynamic behavior of the superconducting film changes substantially, and the correlated magnetic hysteresis loss is significantly reduced due to the presence of the ferromagnetic thin layer. In addition, the spontaneous vortex-antivortex (V-AV) pairs' nucleation in the hybrid bilayer are investigated. © 2014 IOP Publishing Ltd.","ferromagnet-superconductor; Ginzburg-Landau; magnetic domain; superconducting vortice","Ferromagnetic materials; Ferromagnetism; Magnetic domains; Magnetism; Magnetization; Magnets; Nucleation; Superconducting materials; Thin films; Ferromagnetic thin films; Ferromagnets; Ginzburg-Landau; Landau-Lifshitz-Gilbert equations; Magnetic domain patterns; Perpendicular magnetic fields; superconducting vortice; Superconducting vortices; Vortex flow","","","","","","","Larbalestier D., Gurevich A., Feldmann D.M., Polyanskii A., Nature, 414, (2001); Foltyn S.R., Civale L., Macmanus-Driscoll J.L., Jia Q.X., Maiorov B., Wang H., Maley M., Nat. Mater., 6, (2007); Scanlan R.M., Malozemoff A.P., Larbalestier D.C., Proc. IEEE, 92, (2004); Gurevich A., Nat. 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(6602956556); Atxitia, U. (23033487800); Carva, K. (56055065800); Nieves, P. (55360591300); Chubykalo-Fesenko, O. (8264321700); Oppeneer, P.M. (7004167024); Nowak, U. (7003770249)","6602956556; 23033487800; 56055065800; 55360591300; 8264321700; 7004167024; 7003770249","Multiscale modeling of ultrafast element-specific magnetization dynamics of ferromagnetic alloys","2015","Physical Review B - Condensed Matter and Materials Physics","92","5","054412","","","","41","10.1103/PhysRevB.92.054412","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84939817341&doi=10.1103%2fPhysRevB.92.054412&partnerID=40&md5=103491f785abd9aa1a1b15bb03ea4faa","Fachbereich Physik, Universität Konstanz, Konstanz, D-78457, Germany; Zukunftskolleg at Universität Konstanz, Konstanz, D-78457, Germany; Faculty of Mathematics and Physics, DCMP, Charles University, Ke Karlovu 5, Prague 2, CZ-12116, Czech Republic; Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid, 28049, Spain","Hinzke D., Fachbereich Physik, Universität Konstanz, Konstanz, D-78457, Germany; Atxitia U., Fachbereich Physik, Universität Konstanz, Konstanz, D-78457, Germany, Zukunftskolleg at Universität Konstanz, Konstanz, D-78457, Germany; Carva K., Faculty of Mathematics and Physics, DCMP, Charles University, Ke Karlovu 5, Prague 2, CZ-12116, Czech Republic, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Nieves P., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid, 28049, Spain; Chubykalo-Fesenko O., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid, 28049, Spain; Oppeneer P.M., Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden; Nowak U., Fachbereich Physik, Universität Konstanz, Konstanz, D-78457, Germany","A hierarchical multiscale approach to model the magnetization dynamics of ferromagnetic random alloys is presented. First-principles calculations of the Heisenberg exchange integrals are linked to atomistic spin models based upon the stochastic Landau-Lifshitz-Gilbert (LLG) equation to calculate temperature-dependent parameters (e.g., effective exchange interactions, damping parameters). These parameters are subsequently used in the Landau-Lifshitz-Bloch (LLB) model for multisublattice magnets to calculate numerically and analytically the ultrafast demagnetization times. The developed multiscale method is applied here to FeNi (permalloy) as well as to copper-doped FeNi alloys. We find that after an ultrafast heat pulse the Ni sublattice demagnetizes faster than the Fe sublattice for the here-studied FeNi-based alloys. © 2015 American Physical Society.","","","","","","","Seventh Framework Programme, FP7, (281043, 291784)","","Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Phys. Rev. Lett., 76, (1996); Kirilyuk A., Kimel A.V., Rasing T., Rev. Mod. 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Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84939817341" +"Bose T.; Trimper S.","Bose, Thomas (59291320600); Trimper, Steffen (7004240089)","59291320600; 7004240089","Influence of randomness and retardation on the FMR-linewidth","2012","Physica Status Solidi (B) Basic Research","249","1","","172","180","8","5","10.1002/pssb.201147164","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-83455242977&doi=10.1002%2fpssb.201147164&partnerID=40&md5=be01902538b0db8432765b5c249f954d","Martin-Luther-University, 06120 Halle, Von-Seckendorff-Platz 1, Germany","Bose T., Martin-Luther-University, 06120 Halle, Von-Seckendorff-Platz 1, Germany; Trimper S., Martin-Luther-University, 06120 Halle, Von-Seckendorff-Platz 1, Germany","The theory predicts that the spin-wave lifetime τL and the linewidth of ferromagnetic resonance ΔB can be governed by random fields and spatial memory. To that aim the effective field around which the magnetic moments perform a precession is superimposed by a stochastic time dependent magnetic field with finite correlation time. The magnetization dynamics is altered by inclusion of a spatial memory effect monitoring a non-local interaction of size ξ. The underlying Landau-Lifshitz-Gilbert equation (LLG) is modified accordingly. The stochastic LLG is equivalent to a Fokker-Planck equation which enables to calculate the mean values of the magnetization vector. Within the spin-wave approximation we present an analytical solution for the excitation energy and its damping. The lifetime and the linewidth are analyzed depending on the strength of the random field D and its correlation time τc as well as the retardation strength Γ0 and the size ξ. Whereas τL decreases with increasing D, retardation strength Γ0 and τc, the lifetime is enhanced for growing width ξ of the spatial retardation kernel. In the same manner we calculate the experimentally measurable linewidth ΔB is increased strongly when the correlation time τc ranges in the nanosecond interval. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.","Ferromagnetic resonance; Fokker-Planck equation; Magnetization dynamics; Retardation effect","","","","","","","","Ultrathin Magnetic Structures II+III, (2005); Mills D.L., Rezende S.M., Spin Dynamics in Confined Magnetic Structures II, pp. 27-59, (2003); Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T.L., IEEE Trans. Magn., 40, 6, pp. 3443-3449, (2004); Malinowski G., Kuiper K.C., Lavrijsen R., Swagten H.J.M., Koopmans B., Appl. Phys. Lett., 94, (2009); Gilmore K., Idzerda Y.U., Stiles M.D., Phys. Rev. Lett., 99, 2, (2007); Chubykalo-Fesenko O., Nowak U., Chantrell R.W., Garanin D., Phys. Rev. B, 74, 9, (2006); Garanin D.A., Chubykalo-Fesenko O., Phys. Rev. B, 70, 21, (2004); Kazantseva N., Hinzke D., Chantrell R.W., Nowak U., Europhys. 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Status Solidi B Basic Res.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-83455242977" +"Liu Y.-H.; Li Y.-Q.","Liu, Ye-Hua (54417547300); Li, You-Quan (7502084929)","54417547300; 7502084929","A mechanism to pin skyrmions in chiral magnets","2013","Journal of Physics Condensed Matter","25","7","076005","","","","74","10.1088/0953-8984/25/7/076005","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84873303381&doi=10.1088%2f0953-8984%2f25%2f7%2f076005&partnerID=40&md5=fc6b10fe781ca311681fe9d3700deceb","Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027, China","Liu Y.-H., Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027, China; Li Y.-Q., Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027, China","We propose a mechanism to pin skyrmions in chiral magnetic thin films by introducing local maxima of magnetic exchange strength as pinning centers. The local maxima can be realized by engineering the local density of itinerant electrons. The stationary properties and the dynamical pinning and depinning processes of an isolated skyrmion around a pinning center are studied. We carry out numerical simulations of the Landau-Lifshitz-Gilbert (LLG) equation and find a way to control the position of an isolated skyrmion in a pinning center lattice using electric current pulses. The results are verified by a Thiele equation analysis. We also find that the critical current to depin a skyrmion, which is estimated to have order of magnitude 107-108 A m-2, has linear dependence on the pinning strength. © 2013 IOP Publishing Ltd.","","Computer Simulation; Elementary Particles; Magnets; Models, Chemical; Models, Theoretical; Magnetic thin films; Depinning; Electric current pulse; Itinerant electrons; Landau-Lifshitz-Gilbert equations; Linear dependence; Local density; Local maximum; Magnetic exchange; Pinning center; Pinning strength; Skyrmions; Stationary properties; MLCS; MLOWN; article; chemical model; computer simulation; elementary particle; magnet; theoretical model; Flux pinning","","","","","","","Skyrme T.H.R., Nucl. Phys., 31, (1962); Rajaraman R., Solitons and Instantons, (1982); Bogdanov A., Hubert A., J. Magn. Magn. Mater., 138, 3, (1994); Bogdanov A., Hubert A., J. Magn. Magn. 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Liu; Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou 310027, China; email: yhliu@zju.edu.cn","","","","","","","","1361648X","","JCOME","23339842","English","J Phys Condens Matter","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84873303381" +"Hu K.-C.; Lu H.-Y.; Chang C.-C.; Chen H.-H.; Wu F.-S.; Huang C.-H.; Wu T.-C.; Lin L.; Wu J.-C.; Horng L.","Hu, Kuei-Chang (56272244900); Lu, Hong-Yo (56272751100); Chang, Chia-Chi (55387206800); Chen, Hao-Hsuan (57273900900); Wu, Feng-Sheng (24451581500); Huang, Chao-Hsien (23392712400); Wu, Tian-Chiuan (36853976300); Lin, L. (36067990200); Wu, Jong-Ching (57154842800); Horng, Lance (7003351523)","56272244900; 56272751100; 55387206800; 57273900900; 24451581500; 23392712400; 36853976300; 36067990200; 57154842800; 7003351523","Adjustment of demagnetizing field in permalloy nanowires to control domain wall motion","2014","IEEE Transactions on Magnetics","50","1","2273571","","","","7","10.1109/TMAG.2013.2273571","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84904362067&doi=10.1109%2fTMAG.2013.2273571&partnerID=40&md5=125a73a03cf065d8d566007516a40376","Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Department of Electronic Engineering, National Formosa University, Yunlin, Taiwan","Hu K.-C., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Lu H.-Y., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Chang C.-C., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Chen H.-H., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Wu F.-S., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Huang C.-H., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Wu T.-C., Department of Electronic Engineering, National Formosa University, Yunlin, Taiwan; Lin L., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Wu J.-C., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; Horng L., Department of Physics, National Changhua University of Education, Changhua 500, Taiwan","The domain wall motion in permalloy nanowires has been investigated widely due to its potential for a new type of memory. In this paper. we use the LLG Simulator based on the Landau-Lifshitz-Gilbert (LLG) equation to investigate the field-driven domain-wall motion in a long, straight ferromagnetic strip. An injection field of 60 Oe is applied to inject a domain wall from an extended disk into the nanowire. We found a dependence of nanowire dimensions with the velocity of domain wall. By increasing the width of the nanowire, the velocity of the domain wall motion also increases, while theWalker breakdown field (HWB) decreases. On the other hand, increasing the thicknesses of the nanowire, the domain wall velocity, HWB, and demagnetizing field all decrease. By applying a vertical field from 0 to 1000 Oe in order to enhance the demagnetizing field, it is found the HWB is increased from 16 to 20 Oe. © 2013 IEEE.","Demagnetizing field; Domain wall motion; Landau-Lifshitz-Gilbert (LLG) simulation; Walker breakdown","Nanowires; Demagnetizing field; Domain wall motion; Domain wall velocities; Ferromagnetic strips; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Permalloy nanowires; Velocity of domain walls; Domain walls","","","","","","","Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, pp. 190-194, (2008); Ai J.H., Miao B.F., Sun L., You B., Hu A., Ding H.F., Current-induced domain wallmotion in permalloy nanowireswith a rectangular cross-section, J. Appl. Phys., 110, (2011); Hayashi M., Thomas L., Bazaliy Y.B., Rettner C., Moriya R., Jiang X., Parkin S.S.P., Influence of current on field-driven domainwall motion in permalloy nanowires from time resolved measurements of anisotropic magnetoresistance, Phys. Rev. Lett., 96, (2006); Schryer N.L., Walker L.R., The motion of 180 domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, (1974); Bloch F., Zur theorie des austauschproblems und der remanenzerscheinung der ferromagnetika, Z. Phys., 74, (1932); Neel L., Cahiers Phys, 25, (1944); Cowburn R.P., Allwood D.A., Xiong G., Cooke M.D., Domain wall injection and propagation in planar permalloy nanowires, J. Appl. Phys., 91, (2002); McGrouther D., McVitie S., Chapman J.N., Gentils A., Controlled domain wall injection into ferromagnetic nanowires from an optimized pad geometry, Appl. Phys. Lett., 91, (2007); Kunz A., Reiff S.C., Dependence of domain wall structure for low field injection into magnetic nanowires, Appl. Phys. Lett., 94, (2009); Shibata J., Tatara G., Kohno H., A brief review of field- and current-driven domain-wall motion, J. Phys. D: Appl. Phys., 44, (2011); Scheinfein M.R., LLG Micromagnetic Simulator [Online]; Bryan M.T., Shrefl T., Allwood D.A., Dependence of transverse domain wall dynamics on permalloy nanowire dimensions, IEEE Trans. Magn., 46, 5, pp. 1135-1138, (2010); Porter D.G., Donahue M.J., Velocity of transverse domain wall motion along thin, narrow strips, J. Appl. Phys., 95, (2004); Beach G.S.D., Tsoi M., Erskine J.L., Current-induced domain wall motion, J. Magn. Magn. Mater, 320, pp. 1272-1281, (2007)","L. Horng; Department of Physics, National Changhua University of Education, Changhua 500, Taiwan; email: phlhorng@cc.ncue.edu.tw","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84904362067" +"Krivoruchko V.N.","Krivoruchko, V.N. (55406187000)","55406187000","Spin waves damping in nanometre-scale magnetic materials","2015","Fizika Nizkikh Temperatur","41","9","","864","877","13","3","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84938493461&partnerID=40&md5=afd8e2fbda0d3b619be2b45eb93a8dd3","Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine, 46 Nauki Ave., Kyiv, 03680, Ukraine","Krivoruchko V.N., Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine, 46 Nauki Ave., Kyiv, 03680, Ukraine","Spin dynamics in magnetic nanostructured materials is a topic of great current interest. To describe spin motions in such magnetic systems, the phenomenological Landau-Lifshitz (LL), or the LL-Gilbert (LLG), equation is widely used. Damping term is one of the dominant features of magnetization dynamics and plays an essential role in these equations of motion. The form of this term is simple; however, an important question arises whether it provides a proper description of the magnetization coupling to the thermal bath and the related magnetic fluctuations in the real nanometre-scale magnetic materials. It is now generally accepted that for nanostructured systems the damping term in the LL (LLG) equation fails to account for the systematics of the magnetization relaxation, even at the linear response level. In ultrathin films and nanostructured magnets particular relaxation mechanisms arise, extrinsic and intrinsic, which are relevant at nanometre-length scales, yet are not so efficient in bulk materials. These mechanisms of relaxation are crucial for understanding the magnetization dynamics that results in a linewidth dependence on the nanomagnet's size. We give an overview of recent efforts regarding the description of spin waves damping in nanostructured magnetic materials. Three types of systems are reviewed: ultrathin and exchange-based films, magnetic nanometre-scale samples and patterned magnetic structures. The former is an example of a rare case where consideration can be done analytically on microscopic footing. The latter two are typical samples when analytical approaches hardly have to be developed and numerical calculations are more fruitful. Progress in simulations of magnetization dynamics in nanometre-scale magnets gives hopes that a phenomenological approach can provide us with a realistic description of spin motions in expanding diverse of magnetic nanostructures. © V.N. Krivoruchko, 2015.","Gilbert damping; Magnetic nanostructures and nanoelements; Magnetization dynamics; Spin wave relaxation mechanisms","Damping; Equations of motion; Magnetic structure; Magnets; Multilayers; Nanostructured materials; Nanostructures; Spin dynamics; Spin waves; Ultrathin films; Gilbert damping; Magnetization dynamics; Magnetization relaxation; Nanoelements; Nanostructured magnetic materials; Patterned magnetic structure; Phenomenological approach; Spin-wave relaxation; Magnetization","","","","","","","Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., Phys. Rev., 100, (1955); Gilbert T.L., Kelly J.M., Conference on Magnetism and Magnetic Materials, Pittsburgh, PA, 14-16 June, 1955, (1955); Callen H.B., J. Phys. Chem. Solids, 4, (1958); Bar'yakhtar V.G., Sov. Phys. JETP, 60, (1984); Phys. B Condens. Matter, 159, (1998); Bar'yakhtar V.G., Danilevich A.G., Fiz. Nizk. Temp., 36, (2010); Low Temp. Phys., 36, (2010); Low Temp. 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Appl. Phys., 117, (2015); Neusser S., Botters B., Grundler D., Phys. Rev. B, 78, (2008); Kim S.-K., J. Phys. D, 43, (2010); Liu T., Chang H., Vlaminck V., Sun Y., Kabatek M., Hoffmann A., Deng L., Wu M., J. Appl. Phys., 115, 17 A, (2014); Hahn C., Naletov V.V., De Loubens G., Klein O., D'Allivy Kelly O., Anane A., Bernard R., Jacquet E., Bortolotti P., Cros V., Prieto J.L., Munoz M., Appl. Phys. Lett., 104, (2014); Pirro P., Bracher T., Chumak A.V., Lagel B., Dubs C., Surzhenko O., Gornert P., Leven B., Hillebrands B., Appl. Phys. Lett., 104, (2014); Haiming Yu., D'Allivy Kelly O., Cros V., Bernard R., Bortolotti P., Anane A., Brandl F., Huber R., Stasinopoulos I., Grundler D., Sci. Rep., 4, (2014)","V.N. Krivoruchko; Donetsk Institute for Physics and Engineering, National Academy of Sciences of Ukraine, Kyiv, 46 Nauki Ave., 03680, Ukraine; email: krivoruc@gmail.com","","B.Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine","","","","","","01326414","","FNTED","","English","Fiz Nizk Temp","Review","Final","","Scopus","2-s2.0-84938493461" +"Tanaka H.; Nakamura K.; Ichinokura O.","Tanaka, Hideaki (55624472145); Nakamura, Kenji (55516112700); Ichinokura, Osamu (7003759274)","55624472145; 55516112700; 7003759274","Magnetic circuit model considering magnetic hysteresis","2014","IEEJ Transactions on Fundamentals and Materials","134","4","","243","249","6","3","10.1541/ieejfms.134.243","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84898422511&doi=10.1541%2fieejfms.134.243&partnerID=40&md5=5529f2d0f7af66de36123c3f380dff0f","Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Aramaki, Japan","Tanaka H., Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Aramaki, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Aramaki, Japan; Ichinokura O., Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Aramaki, Japan","Quantitative estimation of core loss considering magnetic hysteresis property is strongly required to develop high-efficient electrical machines. This paper presents a novel magnetic circuit model considering magnetic hysteresis. In the proposed model, dc hysteresis loss is calculated by the LLG equation, while classical and anomalous eddy current losses are calculated in the magnetic circuit. It is demonstrated that hysteresis loop under PWM wave excitation can be expressed by the proposed model. The validity and availability are proved by comparing with measured values. © 2014 The Institute of Electrical Engineers of Japan.","Iron loss; LLG equation; Magnetic circuit model; Magnetic hysteresis; PWM excitation","Circuit simulation; Circuit theory; Electric machinery; Magnetic hysteresis; Eddy current-loss; Electrical machine; Iron loss; LLG equation; Magnetic circuit model; Measured values; Quantitative estimation; Wave excitation; Magnetic circuits","","","","","","","Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the landau-lifshitz-gilbert equation for micromagnetics, Jpn. J. Appl. Phys., 28, pp. 2485-2507, (1989); Bertotti G., General properties of power losses in soft ferromagnetic materials, IEEE Trans. Magn., 24, 1, pp. 621-630, (1988)","H. Tanaka; Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Aramaki, Japan; email: power21@ec.ecei.tohoku.ac.jp","","Institute of Electrical Engineers of Japan","","","","","","03854205","","","","Japanese","IEEJ Trans. Fundam. Mater.","Article","Final","","Scopus","2-s2.0-84898422511" +"Imre A.R.; Quiñones-Cisneros S.E.; Deiters U.K.","Imre, Attila R. (7006002957); Quiñones-Cisneros, Sergio E. (55989702200); Deiters, Ulrich K. (7005525464)","7006002957; 55989702200; 7005525464","Adiabatic Processes in the Vapor-Liquid Two-Phase Region. 2. Binary Mixtures","2015","Industrial and Engineering Chemistry Research","54","25","","6559","6568","9","8","10.1021/acs.iecr.5b01247","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84934299901&doi=10.1021%2facs.iecr.5b01247&partnerID=40&md5=0cda6d113f03a2963cb40a576e633e4b","MTA Centre for Energy Research, POB 49, Budapest, H-1525, Hungary; Department of Energy Engineering, Budapest University of Technology and Economics, Muegyetem rkp. 3, D208, Budapest, H-1111, Hungary; Departamento de Reología, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México, 04510, D.F., Mexico; Institute of Physical Chemistry, University of Cologne, Luxemburger Straße 116, Köln, D-50939, Germany","Imre A.R., MTA Centre for Energy Research, POB 49, Budapest, H-1525, Hungary, Department of Energy Engineering, Budapest University of Technology and Economics, Muegyetem rkp. 3, D208, Budapest, H-1111, Hungary; Quiñones-Cisneros S.E., Departamento de Reología, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México, 04510, D.F., Mexico; Deiters U.K., Institute of Physical Chemistry, University of Cologne, Luxemburger Straße 116, Köln, D-50939, Germany","The phase equilibrium conditions and entropy balance equations for multicomponent fluid mixtures are expressed with a density-based formalism (""isochoric thermodynamics""), and isentropes in the one- and two-phase region are computed from equations of state; here the Peng-Robinson equation is used as an example. Griffiths' theorem - one- and two-phase isentropes meet at a maxcondenbar point (pressure maximum of an isopleth) with equal slopes - could be confirmed. For chemically similar compounds at subcritical conditions, the resulting isentrope patterns are similar to those of pure fluids. If one of the components is supercritical, it is possible that, along a part of a two-phase isentrope, the liquid phase has a higher molar entropy than the vapor phase (""entropic inversion""). The phenomenon not only poses a numerical problem, but is also relevant for the question whether a two-phase isentrope can run into the llg three-phase curve. © 2015 American Chemical Society.","","","","","","","Deutsche Forschungsgemeinschaft, (391/36-1)","","Matsuda K., Low heat power generation system, Appl. Therm. Eng., 70, (2014); Shi X., Che D., A combined power cycle utilizing low-temperature waste heat and LNG cold energy, Energy Convers. Manage., 50, (2009); Romero Gomez M., Ferreiro Garcia R., Romero Gomez J., Carbia Carril J., Review of thermal cycles exploiting the exergy of liquefied natural gas in the regasification process, Renew. Sustain. Energy Rev., 38, (2014); Imre A.R., Quinones-Cisneros S.E., Deiters U.K., Adiabatic processes in the liquid-vapor two-phase region. 1. Pure fluids, Ind. Eng. Chem. Res., 53, (2014); Cowperthwaite M., Ahrens T.J., Thermodynamics of the adiabatic expansion of a mixture of two phases, Am. J. Phys., 35, (1967); Rowlinson J.S., Esper G.J., Holste J.C., Hall K.R., Barrufet M.A., Eubank Ph.T., The collinearity of isochores at single- and two-phase boundaries for fluid mixtures, Equations of State-Theories and Applications, 300, pp. 42-59, (1986); Deiters U.K., Kraska Th., High Pressure Fluid Phase Equilibria-Phenomenology and Computation, Supercritical Fluid Science and Technology, 2, (2012); Quinones-Cisneros S.E., Deiters U.K., An efficient algorithm for the calculation of phase envelopes of fluid mixtures, Fluid Phase Equilib., 329, (2012); Marquardt D., An algorithm for least squares estimation of nonlinear parameters, SIAM J. Appl. Math., 11, (1964); Deiters U.K., ThermoC; Peng D.Y., Robinson D.B., A new two-constant equation of state, Ind. Eng. Chem. Fundam., 15, (1976); Robinson D.B., Peng D.Y., The characterization of the heptanes and heavier fractions for the GPA Peng-Robinson program, GPA Res. Rep., RR-28, (1978); Jaubert J.-N., Privat R., Mutelet F., Predicting the phase equilibria of synthetic petroleum fluids with the PPR78 approach, AIChE J., 56, (2010); Qian J.-W., Privat R., Jaubert J.-N., Predicting the phase equilibria, critical phenomena and mixing enthalpies of binary aqueous systems containing alkanes, cycloalkanes, aromatics, alkenes and gases (N2, CO2, H2S, H2) with the PPR78 equation of state, Ind. Eng. Chem. Res., 52, (2013); Barin I., Thermochemical Properties of Pure Substances, 1st Ed., (1989); NIST Chemistry WebBook, (2011); Van Konynenburg P.H., Scott R.L., Critical lines and phase equilibria in binary van der Waals mixtures, Philos. Trans. R. Soc. London A, 298, (1980); Privat R., Jaubert J.-N., Classification of global fluid phase equilibrium behaviors in binary systems, Chem. Eng. Res. Des., 91, (2013); Bolz A., Deiters U.K., Peters C.J., De Loos Th.W., Nomenclature for phase diagrams with particular reference to vapour-liquid and liquid-liquid equilibria, Pure Appl. Chem., 70, (1998); Doiron T., Behringer R.P., Meyer H., Equation of state of a 3He-4He mixture near its liquid-vapor critical point, J. Low Temp. Phys., 24, (1976); Quinones-Cisneros S.E., Barotropic phenomena in complex phase behaviour, Phys. Chem. Chem. Phys., 6, (2004); Stryjek R., Chappelear P.S., Kobayashi R., Low-temperature vapor-liquid equilibria of nitrogen-ethane system, J. Chem. Eng. Data, 19, (1974)","U.K. Deiters; Institute of Physical Chemistry, University of Cologne, Köln, Luxemburger Straße 116, D-50939, Germany; email: ulrich.deiters@uni-koeln.de","","American Chemical Society","","","","","","08885885","","IECRE","","English","Ind. Eng. Chem. Res.","Article","Final","","Scopus","2-s2.0-84934299901" +"Shu C.; Deng L.-W.; Yang B.-C.; Xiong J.; Zuo S.-G.; Liang L.-J.","Shu, Chang (55133338500); Deng, Lian-Wen (7202008013); Yang, Bing-Chu (7404472065); Xiong, Jian (56485080500); Zuo, Shun-Gui (56706978400); Liang, Li-Jie (53866620400)","55133338500; 7202008013; 7404472065; 56485080500; 56706978400; 53866620400","Microwave magnetism of Co-A1-O nano-granular film","2012","Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology)","43","2","","472","476","4","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84858835576&partnerID=40&md5=fadb34dd291d9b1d31f81740fbca483e","School of Physics Science and Technology, Central South University, Changsha 410083, China; State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China","Shu C., School of Physics Science and Technology, Central South University, Changsha 410083, China; Deng L.-W., School of Physics Science and Technology, Central South University, Changsha 410083, China, State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; Yang B.-C., School of Physics Science and Technology, Central South University, Changsha 410083, China; Xiong J., School of Physics Science and Technology, Central South University, Changsha 410083, China; Zuo S.-G., School of Physics Science and Technology, Central South University, Changsha 410083, China; Liang L.-J., School of Physics Science and Technology, Central South University, Changsha 410083, China","To research magnetic characteristics of nano-granular film such as Co-Al-O in the microwave range, related research was studied experimentally and theoretically. Co-Al-O nano-granular films with high microwave permeability were synthesized by magnetron sputtering technology and effect of the major parameters on preparation was discussed. Analytic calculation of effective permeability frequency spectra of the nano-granular thin film was presented based on the Landau-Lifshitz-Gilbert equation and Bruggeman effective medium theory. The results show that the eddy current losses caused by capacitive effect between the particles increase with the increase of the Co sputtering power, and the resonance linewidth broadens. Increased damping parameter will broaden the absorption bandwidth. The simulation results agrees well with the experimental ones.","Co-A1-O nano-granular film; Effective medium theory; LLG equation; Permeability","Engineering; Mathematical models; Mechanical permeability; Analytic calculations; Capacitive effect; Cosputtering; Damping parameters; Eddy current-loss; Effective medium theories; Effective permeability; Frequency spectra; High microwave; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic characteristic; Nanogranular films; Nanogranular thin film; Resonance linewidth; Sputtering technology; Aluminum","","","","","","","Ohnuma S., Lee H.J., Kobayashi N., Et al., Co-Zr-O nano-granular thin films with improved high frequency soft magnetic properties, IEEE Transaction on Magnetics, 37, 41, pp. 2251-2254, (2001); Tetsuya O., Toru A., Jun K., Et al., Development of high-performance magnetic thin film for high-density magnetic recording, Electrochimica Acta, 50, 23, pp. 4576-4579, (2005); Sulitanu N., Brinza F., Excellent soft magnetic two-phase nanocrystalline films for various magnetic devices, Sensors and Actuators A: Physical, 106, 1-3, pp. 212-216, (2003); Yang X.L., Ruan C.L., High frequency properties of Ni 75Fe 25-SiO 2 granular thin films with very high resistivity, Materials Letters, 61, 3, pp. 908-911, (2007); Xiao Y.H., Ge S.H., Zhang B.M., Et al., Fabrication and magnetic properties of Fe 65Co 35-B 2O 3 granular films for high frequency application, IEEE Transactions on Magnetics, 45, 6, pp. 2770-2772, (2009); Jen S.U., Wu T.C., Liu C.H., Piezoresistance characteristics of some magnetic and non-magnetic metal films, Journal of Magnetism and Magnetic Materials, 256, 1-3, pp. 54-59, (2003); Sasaki S., Saito S., Takahashi M., Microstructure and magnetic properties of Co-SiO 2 granular film deposited using sintered targets made from Co, Si, and Co-oxide compounds, Journal of the Magnetics Society of Japan, 33, 4, pp. 362-368, (2009); Deng L.-W., Zhou K.-S., Jiang J.-J., Infulence of conductivity on microwave absorbing ability of nanostructural magnetic metallic film, Journal of Central South University: Science and Technology, 39, 1, pp. 59-63, (2008); Kenji I., Suzuki T., Satot, CoFeSiO/SiO 2 multilayer granular films with very narrow ferromagnetic resonant linewidth, IEEE Transactions on Magnetics, 45, 10, pp. 4290-4293, (2009); Yamagishi Y., Honda S., Inoue J., Numerical simulation of giant magnetoresistance in magnetic multilayers and granular films, Physical Review B: Condensed Matter and Materials Physics, 81, 5, pp. 54445-54449, (2010); Voogt F.C., Palstra T.T.M., Niesen L., Et al., Superparamagnetic behavior of structural domains in epitaxial ultrathin magnetite films, Physical Review B: Condensed Matter and Materials Physics, 57, 14, pp. 8107-8110, (1998); Ohnuma S., Fujimori H., FeCo-Zr-O nanogranular soft-magnect thin films with a high magnetic flux density, Applied Physics Letter, 82, 6, pp. 946-948, (2003); Morikawa T., Suzuki M., Taga Y., Improvement of soft magnetic properties of Co-Cr-O film by additional X (=Rh, Ir, Ag, or Au), Journal of Applied Physics, 83, 5, pp. 6664-6667, (1998); Ikeda K., Kobayashi K., Fujimoto M., Microstructure and magnetic properties of (Co-Fe)-Al-O thin films, Journal of America Ceramic Society, 85, 1, pp. 169-173, (2002); Li S.D., Huang Z.G., Duh J., Et al., Ultrahigh-frequency ferromagnetic properties of FeCoHf films deposited by gradient sputtering, Applied Physics Letter, 92, 6, pp. 92501-92505, (2008)","L.-W. Deng; School of Physics Science and Technology, Central South University, Changsha 410083, China; email: dlw626@163.com","","","","","","","","16727207","","ZDXZA","","Chinese","Zhongnan Daxue Xuebao (Ziran Kexue Ban)","Article","Final","","Scopus","2-s2.0-84858835576" +"Mitsumata C.; Tomita S.; Seki T.; Mizuguchi M.","Mitsumata, Chiharu (6603204999); Tomita, Satoshi (7202940569); Seki, Takeshi (7401920046); Mizuguchi, Masaki (7103201071)","6603204999; 7202940569; 7401920046; 7103201071","Simple analysis for frequency increase in spin torque oscillation","2012","IEEE Transactions on Magnetics","48","11","6332855","3955","3957","2","1","10.1109/TMAG.2012.2201700","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84867837707&doi=10.1109%2fTMAG.2012.2201700&partnerID=40&md5=4cd9f8265029079116083b09c8ad7e43","Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan; Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Ikoma 630-0192, Japan; Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan","Mitsumata C., Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan; Tomita S., Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Ikoma 630-0192, Japan; Seki T., Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan; Mizuguchi M., Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan","The spin torque oscillation (STO) due to magnetic resonance is investigated in term of the Landau-Lifshitz-Gilbert (LLG) equation. An analytic formula of the LLG equation with macro-spins describes a spin state that involves information of an oscillation frequency. The LLG equation can be transformed into an equation of a forced oscillation. The obtained equation includes a frequency of STO, an effective Gilbert damping factor, and an injected spin current.We show that the effective Gilbert damping is given by a linear function of the spin current. Contrastingly, the frequency of STO is not affected by the injected spin current. However, the time-dependent variation of the spin current, e.g., the pulsated spin current, possibly increases the frequency of STO. © 2012 IEEE.","Forced oscillation; Landau-Lifshitz-Gilbert equation; Magnetic resonance; Spin torque","Electrical engineering; Magnetic materials; Analytic formula; Forced oscillations; Gilbert damping; Landau-Lifshitz-Gilbert equations; Linear functions; LLG equation; Oscillation frequency; Spin currents; Spin state; Spin torque; Time-dependent; Magnetic resonance","","","","","Japan Society for the Promotion of Science, JSPS, (23360004, 23654124)","This work was supported in part by a Grant-in-Aid for Scientific Research (23360004) from the Japan Society for the Promotion of Science.","Klselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Microwave oscillations of a nanomagnet driven by a spin-polarized current, Nature, 425, 6956, pp. 380-383, (2003); Suzuki Y., Mizuguchi M., Deac A., Kubota H., Fukushima A., Yuasa S., Maehara H., Djayaprawira D.D., Tsunekawa K., Watanabe N., Microwave properties of spin injection devices - Spontaneous oscillation, spin-torque diode effect and magnetic noise, Magn. Jpn., 2, pp. 282-290, (2007); Slonczewski J.C., Current-driven excitation of magnetic multilayers, Journal of Magnetism and Magnetic Materials, 159, 1-2, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Zhu J.-G., Bertram H.N., Micromagnetic studies of thin metallic films, J. Appl. Phys., 63, pp. 3248-3253, (1988); Kronmuller H., Parkin S., Handbook of Magnetism and Advanced Magnetic Materials, 2, (2007); Mitsumata C., Tomita S., Hagiwara M., Akamatsu K., Electron magnetic resonance in interacting ferromagnetic-metal nanoparticle systems: Experiment and numerical simulation, J. Phys.: Cond. Mater., 22, pp. 016005-101610, (2010); Mitsumata C., Tomita S., Control of Gilbert damping using magnetic metamaterials, Phys. Rev. B, 84, pp. 174421-217446, (2011); Mitsumata C., Tomita S., Analytic solution of Gilbert damping in Landau-Lifshitz-Gilbert equation in magnetic resonance, J. Magn. Soc. Jpn., 36, (2012); Zhu J.-G., Zhu X., Tang Y., Microwave assisted magnetic recording, IEEE Transactions on Magnetics, 44, 1, pp. 125-131, (2008); Slavin A.N., Kabos P., Approximate theory of microwave generation in a current-driven magnetic nanocontact magnetized in an arbitrary direction, IEEE Transactions on Magnetics, 41, 4, pp. 1264-1273, (2005); Krivorotov I.N., Emley N.C., Sankey J.C., Kiselev S.I., Ralph D.C., Buhrman R.A., Time-domain measurements of nanomagnet dynamics driven by spin-transfer torques, Science, 307, 5707, pp. 228-231, (2005); Slavin A., Tiberkevich V., Nonlinear auto-oscillator theory of microwave generation by spin-polarized current, IEEE Trans. Magn., 45, pp. 1875-1918, (2009); Rippard W.H., Pufall M.R., Kaka S., Silva T.J., Russek S.E., Current-driven microwave dynamics in magnetic point contacts as a function of applied field angle, Phys. Rev. B, 70, (2004); Sankey J.C., Braganca P.M., Garcia A.G.F., Krivorotov I.N., Buhrman R.A., Ralph D.C., Spin-transfer-driven ferromagnetic resonance of individual nanomagnets, Phys. Rev. Lett., 96, pp. 227601-227601, (2006); Slonczewski J.C., Currents, torques, and polarization factors in magnetic tunnel junctions, Phys. Rev. B, 71, pp. 024411-102410, (2005)","C. Mitsumata; Department of Applied Physics, Tohoku University, Sendai 980-8579, Japan; email: mitsumata@solid.apph.tohoku.ac.jp","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84867837707" +"Zhang M.; Zhou T.; Yuan Z.","Zhang, Mingsheng (57199245184); Zhou, Tiejun (7402989483); Yuan, Zhimin (7401476834)","57199245184; 7402989483; 7401476834","Analysis of switchable spin torque oscillator for microwave assisted magnetic recording","2015","Advances in Condensed Matter Physics","2015","","457456","","","","6","10.1155/2015/457456","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84925625303&doi=10.1155%2f2015%2f457456&partnerID=40&md5=a087c188ae2e472cad14e6a02e2d8c40","Data Storage Institute, Agency for Science, Technology and Research ASTAR, Singapore, 117608, Singapore","Zhang M., Data Storage Institute, Agency for Science, Technology and Research ASTAR, Singapore, 117608, Singapore; Zhou T., Data Storage Institute, Agency for Science, Technology and Research ASTAR, Singapore, 117608, Singapore; Yuan Z., Data Storage Institute, Agency for Science, Technology and Research ASTAR, Singapore, 117608, Singapore","A switchable spin torque oscillator (STO) with a negative magnetic anisotropy oscillation layer for microwave assisted magnetic recording is analyzed theoretically and numerically. The equations for finding the STO frequency and oscillation angle are derived from Landau-Lifshitz-Gilbert (LLG) equation with the spin torque term in spherical coordinates. The theoretical analysis shows that the STO oscillating frequency remains the same and oscillation direction reverses after the switching of the magnetization of the spin polarization layer under applied alternative magnetic field. Numerical analysis based on the derived equations shows that the oscillation angle increases with the increase of the negative anisotropy energy density (absolute value) but decreases with the increase of spin current, the polarization of conduction electrons, the saturation magnetization, and the total applied magnetic field in the z direction. The STO frequency increases with the increase of spin current, the polarization of conduction electrons, and the negative anisotropy energy density (absolute value) but decreases with the increase of the saturation magnetization and the total applied magnetic field in the z direction. © 2015 Mingsheng Zhang et al.","","","","","","","","","Slonczewski J.C., Current-driven excitation of magnetic multilayers, Journal OfMagnetism and MagneticMaterials, 159, 1-2, pp. L1-L7, (1996); Stiles M.D., Miltat J., Spin-transfer torque and dynamics, Spin Dynamics in Confined Magnetic Structures III, pp. 225-308, (2006); Li Z., Zhang S., Magnetization dynamics with a spintransfer torque, Physical Review B - Condensed Matter and Materials Physics, 68, 2, (2003); Zhu J.-G., Zhu X., Tang Y., Microwave assisted magnetic recording, IEEE Transactions on Magnetics, 44, 1, pp. 125-131, (2008); Zhu J.-G., Wang Y., Microwave assistedmagnetic recording utilizing perpendicular spin torque oscillator with switchable perpendicular electrodes, IEEE Transactions OnMagnetics, 46, 3, pp. 751-757, (2010); Yoshida K., Yokoe M., Ishikawa Y., Kanai Y., Spin torque oscillator with negative magnetic anisotropy materials for MAMR, IEEE Transactions on Magnetics, 46, 6, pp. 2466-2469, (2010); Moodera J.S., Mathon G., Spin polarized tunneling in ferromagnetic junctions, Journal of Magnetism and Magnetic Materials, 200, 1, pp. 248-273, (1999)","","","Hindawi Publishing Corporation","","","","","","16878108","","","","English","Adv. Condens. Matter Phys.","Article","Final","All Open Access; Gold Open Access; Green Open Access","Scopus","2-s2.0-84925625303" +"Li Y.; Xu B.; Hu S.; Li Y.; Li Q.; Liu W.","Li, Yi (59071988900); Xu, Ben (55758000000); Hu, Shenyang (25632233200); Li, Yulan (55894830800); Li, Qiulin (24478762200); Liu, Wei (56593718800)","59071988900; 55758000000; 25632233200; 55894830800; 24478762200; 56593718800","Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles","2015","AIP Advances","5","7","077168","","","","7","10.1063/1.4927548","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84938152174&doi=10.1063%2f1.4927548&partnerID=40&md5=7741f26b1b9f40d23708c4024a5db95e","School of Material Science and Engineering, Tsinghua University, Beijing, 100084, China; Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China; Energy Materials Division, Pacific Northwest National Laboratory, Richland, 99352, WA, United States","Li Y., School of Material Science and Engineering, Tsinghua University, Beijing, 100084, China, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China; Xu B., School of Material Science and Engineering, Tsinghua University, Beijing, 100084, China; Hu S., Energy Materials Division, Pacific Northwest National Laboratory, Richland, 99352, WA, United States; Li Y., Energy Materials Division, Pacific Northwest National Laboratory, Richland, 99352, WA, United States; Li Q., School of Material Science and Engineering, Tsinghua University, Beijing, 100084, China, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China; Liu W., School of Material Science and Engineering, Tsinghua University, Beijing, 100084, China, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China","The magnetic hysteresis loops and Barkhausen noise of a single α-iron with nonmagnetic particles are simulated to investigate into the magnetic hardening due to Cu-rich precipitates in irradiated reactor pressure vessel (RPV) steels. Phase field method basing Landau-Lifshitz-Gilbert (LLG) equation is used for this simulation. The results show that the presence of the nonmagnetic particle could result in magnetic hardening by making the nucleation of reversed domains difficult. The coercive field is found to increase, while the intensity of Barkhausen noise voltage is decreased when the nonmagnetic particle is introduced. Simulations demonstrate the impact of nucleation field of reversed domains on the magnetization reversal behavior and the magnetic properties. © 2015 Author(s).","","Hardening; Hysteresis; Hysteresis loops; Magnetic hysteresis; Magnetic materials; Magnetism; Magnetization reversal; Nucleation; Phase transitions; Pressure vessels; Cu-rich precipitates; Landau-Lifshitz-Gilbert equations; Magnetic Barkhausen-noise; Magnetic hardening; Non-magnetic particles; Nucleation field; Phase field methods; Reactor pressure vessel steels; Magnetic bubbles","","","","","","","Eason E.D., Odette G.R., Nanstad R.K., Yamamoto T., J. Nucl. Mater, 433, (2013); Miller M.K., Powers K.A., Nanstad R.K., Efsing P., J. Nucl. Mater., 437, (2013); Lucas G.E., J. Nucl. Mater., 407, (2010); Gurovich B.A., Kuleshova E.A., Nikolaev Y.A., Shtrombakh Y.I., J. Nucl. Mater., 246, (1997); Odette G.R., Yamamoto T., Klingensmith D., Phil. Mag., 85, (2005); Chaouadi R., Gerard R., J Nucl Mater., 345, (2005); Fujii K., Ohkubo T., Fukuya K., J Nucl Mater., 417, (2011); Yamashita N., Iwasaki M., Dozaki K., Soneda N., J. Eng. Gas Turb. Power., 132, (2010); Park D.G., Kim C.G., Kim H.C., Hong J.H., Kim I.S., J. Appl. Phys., 81, (1997); Chi S., Chang K., Hong J., Kuk I., Kim C., J. Appl. Phys., 104, (1999); Chang K., Chi S., Choi K., Kim B., Lee S., Int. J. Pres. Ves. Pip., 79, (2002); Kempf R.A., Sacanell J., Milano J., Guerra Mendez N., Winkler E., Butera A., Troiani H., Saleta M.E., Fortis A.M., J. Nucl. Mater., 445, (2014); Kobayashi S., Yamamoto T., Klingensmith D., Odette G.R., Kikuchi H., Kamada Y., J. Nucl. Mater., 422, (2012); Pirfo Barroso S., Horvath M., Horvath A., Nucl. Eng. Des., 240, (2010); Park D.G., Park I.G., Kim W.W., Cheong Y.M., Hong J.H., Nucl. Eng. Des., 238, (2008); Park D.G., Park S.S., Ju J.S., Chang K.O., Hong J.H., J. Magn. Magn. Mater., 272, (2004); Asoka-Kumar P., Wirth B.D., Sterne P.A., Howell R.H., Odette G.R., Phil. Mag. Lett., 82, (2002); Lo C.C.H., J. Appl. Phys., 111, (2012); Gilbert T.L., IEEE T. Magn., 40, (2004); Zhang J.X., Chen L.Q., Acta Mater., 53, (2005); Wang X., Garcia-Cervera C.J., J. Comput. Phys., 171, (2001); Hu S.Y., Li Y.L., McCloy J., Montgomery R., Henager Jr.C., IEEE Mag. Lett., 4, (2013); Perez-Benitez J.A., Espina-Hernandez J.H., Martinez-Ortiz P., Chavez-Gonzalez A.F., De La Rosa J.M., J. Magn. Magn. Mater., 347, (2013); Alessandro B., Beatrice C., Bertotti G., Montorsi A., J. Appl. Phys., 68, (1990); Yamaguchi K., Tanaka S., Nittono O., Yamada K., Takagi T., IEEE T. Magn., 41, (2005); Cullity B.D., Graham C.D., Introduction to Magnetic Materials, (2009); Sakamoto H., Okada M., Homma M., IEEE T. Magn., 23, (1987); Yamaguchi K., Tanaka S., Nittono O., Yamada K., Takagi T., IEEE T. Magn., 42, (2006)","","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-84938152174" +"Xu F.; Huang Q.; Liao Z.; Li S.; Ong C.K.","Xu, Feng (55652604800); Huang, Qijun (55428622700); Liao, Zhiqin (53866550400); Li, Shandong (7409239876); Ong, C.K. (35467147500)","55652604800; 55428622700; 53866550400; 7409239876; 35467147500","Tuning of magnetization dynamics in sputtered CoFeB thin film by gas pressure","2012","Journal of Applied Physics","111","7","07A304","","","","21","10.1063/1.3670605","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861727509&doi=10.1063%2f1.3670605&partnerID=40&md5=1fd11750c1ba81854cb37c328068203f","School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China; Physics Department, Fujian Normal University, Fuzhou 350007, China; Physics Department, National University of Singapore, Singapore 117542, Singapore","Xu F., School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China, Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China; Huang Q., School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Liao Z., School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; Li S., Physics Department, Fujian Normal University, Fuzhou 350007, China; Ong C.K., Physics Department, National University of Singapore, Singapore 117542, Singapore","The influences of sputtering gas pressure on the high-frequency magnetization dynamics of as-sputtered CoFeB thin films are studied with permeability spectra based on the Landau-Lifshitz-Gilbert (LLG) equation. Results show that with the pressure increasing, both the anisotropy field and resonance frequency have minimums, while the initial permeability shows a maximum. The damping factor deceases monotonously with the pressure increasing, similar as with the coercivity. The high tunability of the damping factor indicates that controlling sputtering gas pressure could be an effective method in tuning the magnetization dynamics. All these dependences on gas pressure are suggested to be related to the inner stress of these sputtered films. © 2012 American Institute of Physics.","","Cobalt compounds; Magnetization; Thin films; Anisotropy field; CoFeB thin films; Damping factors; Gas pressures; High tunability; High-frequency magnetization; Initial permeability; Inner stress; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Permeability spectrum; Resonance frequencies; Sputtered films; Sputtering gas pressure; Dynamics","","","","","National Natural Science Foundation of China, NSFC, (10904071, 11074040, 11079022); Natural Science Foundation of Jiangsu Province, (SBK200922570); Nanjing University of Science and Technology, NUST, (2011ZDJH04)","This work is supported by National Natural Science Foundation of China under contract Nos. 10904071, 11074040 and 11079022, by Natural Science Foundation of Jiangsu Province under contract Nos. SBK200922570, also by NUST research funding, No. 2011ZDJH04.","Hayakawa Y., Makino A., Fujimori H., Inoue A., J. Appl. Phys., 81, (1997); Ohnuma M., Hono K., Onodera H., Ohnuma S., Fujimori H., Pedersen J.S., J. Appl. Phys., 87, (2000); Yoshida C., Kurasawa M., Lee Y.M., Aoki M., Sugiyama Y., Appl. Phys. Lett., 92, (2008); Bilzer C., Devolder T., Kim J.-V., Counil G., Chappert C., Cardoso S., Freitas P.P., J. Appl. Phys., 100, (2006); Seemann K., Leiste H., Kovcs A., J. Magn. Magn. Mater., 320, (2008); Fal T.J., Veerakumar V., Kuanr B., Khivintsev Y.V., Celinski Z., Camley R.E., J. Appl. Phys., 102, (2007); Khivintsev Y.V., Kuanr B.K., Harward I., Camley R.E., Celinski Z., J. Appl. Phys., 99, (2006); McCord J., Kaltofen R., Schmidt O.G., Schultz L., Appl. Phys. Lett., 92, (2008); Xu F., Phuoc N.N., Zhang X., Ma Y., Chen X., Ong C.K., J. Appl. Phys., 104, (2008); Liu Y., Chen L.F., Tan C.Y., Liu H.J., Ong C.K., Rev. Sci. Instrum., 76, (2005); Bailey W., Kabos P., Mancoff F., Russek S., IEEE Trans. Magn., 37, (2001); Hoffmann H., Thin Solid Films, 58, (1979); Zou P., Yu W., Bain J.A., IEEE Trans. Magn., 38, (2002); Ohnuma S., Fujimori H., Furukawa S., Matsumoto F., Masumoto T., Mater. Sci. Eng. A, 181-182, (1994); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Youssef J.B., Vukadinovic N., Billet D., Labrune M., Phys. Rev. B, 69, (2004)","F. Xu; School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; email: xufeng@mail.njust.edu.cn","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-84861727509" +"Baňas L.; Page M.; Praetorius D.","Baňas, L. (24079505700); Page, M. (55597570300); Praetorius, D. (6507452481)","24079505700; 55597570300; 6507452481","A convergent linear finite element scheme for the Maxwell-landau-lifshitz-gilbert equations","2015","Electronic Transactions on Numerical Analysis","44","","","250","270","20","11","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84937423768&partnerID=40&md5=5ec2451944b7df145d6a34458ec917eb","Fakultät Für Mathematik, Universität Bielefeld, Postfach 100 131, Bielefeld, 33501, Germany; Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria","Baňas L., Fakultät Für Mathematik, Universität Bielefeld, Postfach 100 131, Bielefeld, 33501, Germany; Page M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; Praetorius D., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria","We consider the lowest-order finite element discretization of the nonlinear system of Maxwell's and Landau-Lifshitz-Gilbert equations (MLLG). Two algorithms are proposed to numerically solve this problem, both of which only require the solution of at most two linear systems per time step. One of the algorithms is decoupled in the sense that it consists of the sequential computation of the magnetization and afterwards the magnetic and electric field. Under some mild assumptions on the effective field, we show that both algorithms converge towards weak solutions of the MLLG system. Numerical experiments for a micromagnetic benchmark problem demonstrate the performance of the proposed algorithms. Copyright © 2015, Kent State University.","Convergence; Ferromagnetism; Linear scheme; Maxwell-LLG","Benchmarking; Electric fields; Ferromagnetism; Finite element method; Linear systems; Nonlinear equations; Convergence; Finite-element discretization; Landau-Lifshitz-Gilbert equations; Linear scheme; Magnetic and electric fields; Maxwell-Landau-Lifshitz-Gilbert equation; Maxwell-LLG; Sequential computations; Maxwell equations","","","","","","","Abert C., Hrkac G., Page M., Praetorius D., Ruggeri M., Suss D., Spin-polarized transport in ferromagnetic multi layers: An unconditionally convergent FEM integrator, Comput. Math. Appl., 68, pp. 639-654, (2014); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Kritsikis E., Toussaint J., A convergent finite element approximation for Landau- Lifshitz-Gilbert equation, Phys. B, 407, pp. 1345-1349, (2012); Alouges F., Kritsikis E., Toussaint J., A convergent and precise finite element scheme for Landau-Lifschitz-Gilbert equation, Numer. Math., 128, pp. 407-430, (2014); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Benas L., An efficient multi grid preconditioner for Maxwell's equations in micro magnetism, Math. Comput. Simulation, 80, pp. 1657-1663, (2010); Benas L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell- Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 46, pp. 1399-1422, (2008); Benas L., Brzezniak Z., Prohl A., Computational studies for the stochastic Landau-Lifshitz-Gilbert equation, SIAM J. Sci. Comput., 35, pp. B62-B81, (2013); Benas L., Page M., Praetorius D., A convergent linear finite element scheme for the Maxwell- Landau-Lifshitz-Gilbert equation, ASC Report 09/2013, Institute for Analysis and Scientific Computing, (2013); Benas L., Page M., Praetorius D., Rochat J., On the Landau-Lifshitz-Gilbert equations with magnetostriction, IMA J. Numer. Anal., 34, pp. 1361-1385, (2014); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, pp. 220-238, (2005); Bartels S., Projection-free approximation of geometrically constrained partial differential equations, Math. Comp., (2015); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comp., 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 44, pp. 1405-1419, (2006); Brenner S., Scott L., The Mathematical Theory of Finite Element Methods, (2002); Bruckner F., Suess D., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Ruggeri M., Multiscale modeling in micro magnetics: Well-posedness and numerical integration, Math. Models Methods Appl. Sci., 24, pp. 2627-2662, (2014); Bruckner F., Vogler C., Bergmair B., Huber T., Fuger M., Suess D., Feischl M., Fuhrer T., Page M., Praetorius D., Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulation, J. Magn. Magn. Mater., 343, pp. 163-168, (2013); Carbou G., Fabrie P., Time average in micro magnetism, J. Differential Equations, 147, pp. 383-409, (1998); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Methods Eng., 15, pp. 277-309, (2008); D'Aquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, J. Comput. Phys., 209, pp. 730-753, (2005); Elstrodt J., Maß- Und Integrationstheorie, (2009); Garcia-Cervera C.J., Numerical micro magnetics: A review, Bol. Soc. Esp. Mat. Apl. CeMA, 39, pp. 103-135, (2007); Hrkac G., Combining Eddy-Current and Micromagnetic Simulations with Finite-Element Method, (2005); Goldenits P., Konvergente Numerische Integration Der Landau-Lifshitz-Gilbert Gleichung, (2012); Goldenits P., Hrkac G., Mayr M., Praetorius D., Suess D., An effective integrator for the Landau-Lifshitz-Gilbert equation, Proceedings of Mathmod 2012 Conference, pp. 493-497, (2014); Goldenits P., Praetorius D., Suess D., Convergent geometric integrator for the Landau-Lifshitz- Gilbert equation in micro magnetics, Proc. Appl. Math. Mech., 11, pp. 775-776, (2011); Hubert A., Schafer R., Magnetic Domains. the Analysis of Magnetic Microstructures, (1998); Le K., Page M., Praetorius D., Tran T., On a decoupled linear FEM integrator for eddy-current- LLG, Appl. Anal., (2014); Le K., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz- Gilbert equations, Comput. Math. Appl., 66, pp. 1389-1402, (2013); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); Monk P.B., Finite Element Methods for Maxwell's Equations, (2003); Monk P.B., Vacus O., Accurate discretization of a non-linear micromagnetic problem, Comput. Methods Appl. Mech. Engrg., 190, pp. 5243-5269, (2001); Page M., On Dynamical Micromagnetism, (2013); Prohl A., Computational Micromagnetism, (2001); Rivas J., Zamarro J.M., Martin E., Pereira C., Simple approximation for magnetization curves and hysteresis loops, IEEE Trans. Magn., 17, pp. 1498-1502, (1981); Verfurth R., A Review of a Posteriori Error Estimation and Adaptive Mesh-Refinement Techniques, (1996); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Japan J. Appl. Math., 2, pp. 69-84, (1985)","","","Kent State University","","","","","","10689613","","","","English","Electron. Trans. Numer. Anal.","Article","Final","","Scopus","2-s2.0-84937423768" +"Nishino M.; Miyashita S.","Nishino, Masamichi (7103009415); Miyashita, Seiji (7102333760)","7103009415; 7102333760","Realization of the thermal equilibrium in inhomogeneous magnetic systems by the Landau-Lifshitz-Gilbert equation with stochastic noise, and its dynamical aspects","2015","Physical Review B - Condensed Matter and Materials Physics","91","13","134411","","","","39","10.1103/PhysRevB.91.134411","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84928821241&doi=10.1103%2fPhysRevB.91.134411&partnerID=40&md5=c1bebb992e7525308b6a4a5774400e1f","Computational Materials Science Center, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047, Japan; Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-Ku, Tokyo, Japan; CREST, JST, 4-1-8 Honcho Kawaguchi, Saitama, 332-0012, Japan","Nishino M., Computational Materials Science Center, National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047, Japan; Miyashita S., Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-Ku, Tokyo, Japan, CREST, JST, 4-1-8 Honcho Kawaguchi, Saitama, 332-0012, Japan","It is crucially important to investigate the effects of temperature on magnetic properties such as critical phenomena, nucleation, pinning, domain wall motion, and coercivity. The Landau-Lifshitz-Gilbert (LLG) equation has been applied extensively to study dynamics of magnetic properties. Approaches of Langevin noises have been developed to introduce the temperature effect into the LLG equation. To have the thermal equilibrium state (canonical distribution) as the steady state, the system parameters must satisfy some condition known as the fluctuation-dissipation relation. In inhomogeneous magnetic systems in which spin magnitudes are different at sites, the condition requires that the ratio between the amplitude of the random noise and the damping parameter depend on the magnitude of the magnetic moment at each site. Focused on inhomogeneous magnetic systems, we systematically showed agreement between the stationary state of the stochastic LLG equation and the corresponding equilibrium state obtained by Monte Carlo simulations in various magnetic systems including dipole-dipole interactions. We demonstrated how violations of the condition result in deviations from the true equilibrium state. We also studied the characteristic features of the dynamics depending on the choice of the parameter set. All the parameter sets satisfying the condition realize the same stationary state (equilibrium state). In contrast, different choices of parameter set cause seriously different relaxation processes. We show two relaxation types, i.e., magnetization reversals with uniform rotation and with nucleation. © 2015 American Physical Society.","","","","","","","Japan Society for the Promotion of Science, JSPS, (26400324)","","Kronmullar H., Fahnle M., Micromagnetism and the Microstructure of Ferromagnetic Solids, (2003); Garanin D.A., Phys. Rev. B, 55, (1997); Nishino M., Boukheddaden K., Konishi Y., Miyashita S., Phys. Rev. Lett., 98, (2007); Nose S., J. Chem. Phys., 81, (1984); Hoover W.G., Phys. Rev. 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B, 84, (2011); Peczak P., Ferrenberg A.M., Landau D.P., Phys. Rev. B, 43, (1991); Skadsem H.J., Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. B, 75, (2007); Simanek E., Heinrich B., Phys. Rev. B, 67, (2003); Kambersky V., Phys. Rev. B, 76, (2007); Gilmore K., Idzerda Y.U., Stiles M.D., Phys. Rev. Lett., 99, (2007); Gilmore K., Idzerda Y.U., Stiles M.D., J. Appl. Phys., 103, (2008); Brataas A., Tserkovnyak Y., Bauer G.E., Phys. Rev. Lett., 101, (2008); Starikov A.A., Kelly P.J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 105, (2010); Ebert H., Mankovsky S., Kodderitzsch D., Kelly P.J., Phys. Rev. Lett., 107, (2011); Sakuma A., J. Phys. Soc. Jpn., 4, (2012); Sakuma A., J. Appl. Phys., 117, (2015); Kubo R., J. Math. Phys., 4, (1963)","","","American Physical Society","","","","","","10980121","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-84928821241" +"Li D.; Wang Z.; Han X.; Li Y.; Guo X.; Zuo Y.; Xi L.","Li, Dong (56375967500); Wang, Zhen (57196468455); Han, Xuemeng (57196233173); Li, Yue (55917774500); Guo, Xiaobin (56297813400); Zuo, Yalu (9244829500); Xi, Li (35091752500)","56375967500; 57196468455; 57196233173; 55917774500; 56297813400; 9244829500; 35091752500","Improved high-frequency soft magnetic properties of FeCo films on organic ferroelectric PVDF substrate","2015","Journal of Magnetism and Magnetic Materials","375","","","33","37","4","12","10.1016/j.jmmm.2014.09.048","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84907966501&doi=10.1016%2fj.jmmm.2014.09.048&partnerID=40&md5=bb81618f87f2e48e55fbd1eac12ea514","Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China","Li D., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Wang Z., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Han X., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Li Y., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Guo X., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Zuo Y., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China; Xi L., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China","FeCo films with various thicknesses were fabricated by direct-current magnetron sputtering on corning glass and organic ferroelectric PVDF substrates at the same time with 5 nm Ru seed layer and 5 nm Ta protective layer. The in-plane uniaxial anisotropy field of FeCo on glass substrate increases from 24 to 36 Oe with the increase of FeCo film thickness from 5 to 100 nm. However, a large in-plane anisotropy field of FeCo on PVDF substrate increases with FeCo thickness from 5 to 20 nm and gradually decreases with the FeCo thickness further increasing. Atomic force microscope images of FeCo on glass show quite smooth surface with root-mean-square roughness around 0.5 nm and have none visible granules on the surface for all samples. While, AFM images of FeCo on PVDF show quite rough surface with RMS roughness around 25 nm and have visible granules with the smallest granules appearing at the FeCo thickness of 20 nm. The permeability spectra show the typical ferromagnetic resonance phenomenon and can be well fitted by the LLG equation with the obtained experimental parameters. The ferromagnetic resonance frequency can reach 7.0 GHz for the 20 nm FeCo film on PVDF. Moreover, the quality factor of this sample can respectively reach 26, 12 and 7 at 1.0, 2.0, and 3.0 GHz, indicating the potential real 3G application for high-frequency devices. © 2014 Elsevier B.V.","Flexible organic substrate; High frequency property; Magnetic thin film","Anisotropy; Atomic force microscopy; Binary alloys; Cobalt alloys; Ferroelectric films; Ferroelectricity; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Glass; Granulation; Magnetic thin films; Substrates; Surface roughness; Atomic force microscope images; Direct current magnetron sputtering; Ferromagnetic resonance frequency; High-frequency properties; Organic substrate; Root mean square roughness; Soft magnetic properties; Uniaxial anisotropy fields; Iron alloys","","","","","CERS of China, (CERS-1-89); National Natural Science Foundation of China, NSFC, (51101079, 51171076); National Natural Science Foundation of China, NSFC; Fundamental Research Funds for the Central Universities, (Lzujbky-2012-27); Fundamental Research Funds for the Central Universities; National Science Fund for Distinguished Young Scholars, (50925103); National Science Fund for Distinguished Young Scholars","This work was supported by the National Science Fund for Distinguished Young Scholars (No. 50925103 ), the National Natural Science Foundation of China (Nos. 51171076 and 51101079 ), the Fundamental Research Funds for the Central Universities (No. Lzujbky-2012-27 ) and the CERS of China (No. CERS-1-89 ).","Seemann K., Leiste H., Ziebert C., J. 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(55757046000); Wang, L.S. (36051995400); Xu, R. (55757624000); Luo, Q. (55285575300); Xu, L. (57199907132); Yuan, B.B. (56342524900); Zou, C.Y. (56342462700); Wang, J.B. (55538378900); Peng, D.L. (25722616700)","55757046000; 36051995400; 55757624000; 55285575300; 57199907132; 56342524900; 56342462700; 55538378900; 25722616700","Influence of total film thickness on high-frequency magnetic properties of the [FeCoSiN/SiNx]n multilayer thin films","2015","Journal of Magnetism and Magnetic Materials","374","","","85","91","6","18","10.1016/j.jmmm.2014.08.028","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84906771399&doi=10.1016%2fj.jmmm.2014.08.028&partnerID=40&md5=66e4e3c4b0376229bc6457fbac9d4ebe","Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China","Liu X.L., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Wang L.S., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Xu R., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Luo Q., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Xu L., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Yuan B.B., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Zou C.Y., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; Wang J.B., Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China; Peng D.L., Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China","[FeCoSiN/SiNx]n multilayer thin films with different number of layers were fabricated by alternating magnetron sputtering at room temperature with no external magnetic field applied on substrates. A well-defined laminated structure consisting of 7 nm FeCoSiN magnetic layer and 2 nm SiNx insulating layer was observed by transmission electron microscopy (TEM). The static magnetic hysteresis loops of the [FeCoSiN/SiN x]n multilayer thin films measured by vibrating sample magnetometer (VSM) presented an obvious in-plane uniaxial magnetic anisotropy. The dynamic magnetic performance of the [FeCoSiN/SiNx]n multilayer films was studied by vector network analyzer and LLG equation. The results indicated that the total film thickness has slightly impact on the high-frequency magnetic performance of the multilayer thin films. When the total thickness of the [FeCoSiN/SiNx]n multilayer thin films increased to micron level, they could still maintain encouraging high-frequency magnetic properties and electrical property: the ferromagnetic resonance frequency fr=3.74 GHz, real permeability μ′=93.73, and electrical resistivity ρ=196 μΩ cm. © 2014 Elsevier B.V.","High-frequency magnetic property; In-plane uniaxial magnetic anisotropy; Multilayer film; Soft magnetic film","Film thickness; Magnetic anisotropy; Magnetic materials; Silicon nitride; Transmission electron microscopy; Anisotropy; Electric network analyzers; Film preparation; Film thickness; Magnetic anisotropy; Magnetic materials; Magnetic properties; Magnetism; Multilayers; Silicon nitride; Thin films; Transmission electron microscopy; External magnetic field; Ferromagnetic resonance frequency; High frequency HF; Multi-layer thin film; Soft magnetic films; Uniaxial magnetic anisotropy; Vector network analyzers; Vibrating sample magnetometer; Multilayer films; Multilayer films","","","","","National Natural Science Foundation of China, NSFC, (51171158, 51301145, 51371154); National Natural Science Foundation of China, NSFC; Natural Science Foundation of Fujian Province, (2014J05009); Natural Science Foundation of Fujian Province; National Basic Research Program of China (973 Program), (2012CB933103); National Basic Research Program of China (973 Program)","The authors gratefully acknowledge financial support from the National Basic Research Program of China (No. 2012CB933103 ), the National Natural Science Foundation of China (Nos. 51171158 , 51371154 and 51301145 ), and the Natural Science Foundation of Fujian Province of China (No. 2014J05009 ).","Kim J., Kim M., Galle P., Herrault F., Shafer R., Park J.Y., Allen M.G., IEEE Trans. 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Soc., 139, pp. 1151-1159, (1992); Yang W., Deng Z., Zhang D., Ke P., Wang A., Acta Metall. Sin., 26, pp. 693-698, (2013); Okada T., Gokita M., Yuasa M., Sekine I., J. Electrochem. Soc., 145, pp. 815-822, (1998); McCord J., Erkartal B., Von Hofe T., Kienle L., Quandt E., Roshchupkina O., J. Appl. Phys., 113, (2013); Phuoc N.N., Ong C.K., Adv. Mater., 25, pp. 980-984, (2013); Ge S., Yao D., Yamaguchi M., Yang X., Zuo H., Ishii T., Zhou D., Li F., J. Phys. D Appl. Phys., 40, pp. 3660-3664, (2007); Mircea D.I., Clinton T.W., Appl. Phys. Lett., 90, (2007)","L.S. Wang; Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005, China; email: wangls@xmu.edu.cn","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84906771399" +"Topkaya R.; Kazan S.; Yilgin R.; Akdoğan N.; Özdemir M.; Aktaş B.","Topkaya, Ramazan (26538904100); Kazan, Sinan (6701313442); Yilgin, Resul (9244881300); Akdoğan, Numan (8535680500); Özdemir, Mustafa (57201735818); Aktaş, Bekir (7005730975)","26538904100; 6701313442; 9244881300; 8535680500; 57201735818; 7005730975","Ferromagnetic resonance studies of exchange biased CoO/Fe bilayer grown on MgO substrate","2014","Journal of Superconductivity and Novel Magnetism","27","6","","1503","1512","9","6","10.1007/s10948-013-2464-1","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84901634723&doi=10.1007%2fs10948-013-2464-1&partnerID=40&md5=85f9b4a296cc1b3dc57d5eeb7304f22e","Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; Department of Physics, Marmara University, 34722 Istanbul, Turkey","Topkaya R., Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; Kazan S., Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; Yilgin R., Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; Akdoğan N., Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; Özdemir M., Department of Physics, Marmara University, 34722 Istanbul, Turkey; Aktaş B., Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey","Dynamic and static magnetizations of an exchange biased bilayer system which is constructed as a proximity of a CoO layer on an Fe-layer grown on the (100) oriented MgO substrate by ion beam sputtering technique have been investigated by ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) techniques. The room-temperature FMR measurements reveal that the Fe layer is epitaxially grown on MgO substrate with four-fold magnetocrystalline anisotropy and the hard magnetization axis of the sample is the [100] crystallographic directions of MgO substrate. We have determined the g-value, effective magnetization, magnetocrystalline anisotropy constants and contributions to FMR linewidth due to the intrinsic Gilbert damping and inhomogeneity of magnetization by using Landau-Lifshitz-Gilbert (LLG) equation. We observed an unusual FMR line shape attributed to impedance switching of resonance cavity and complex component of conductivity of sample system. The low-temperature FMR measurement shows asymmetric hysteretic behavior of resonance field related to magnetic coupling of ferromagnetic and antiferromagnetic layers. From both FMR and VSM measurements between 10-300 K, the magnetocrystalline anisotropy is observed to dominate above blocking temperature, while unidirectional anisotropy is observed to dominate below blocking temperature over internal magnetic anisotropy. FMR spectra have a comparatively small linewidth between 40-100 Oe, which indicates to a high crystallinity of the Fe film. Gilbert constant was calculated as 0.007 from the linewidth fitting of FMR spectra. This small value is a suitable for reducing the critical switching current used in magnetic tunneling junction. Detailed exchange bias studies were carried out for hard and easy axis of the sample in the temperature range of 10-300 K. From both low-temperature FMR and VSM measurements, the blocking temperature of the system was determined as ∼60 K. © 2013 Springer Science+Business Media New York.","Antiferromagnetic materials; Exchange bias; Ferromagnetic resonance; Gilbert damping parameter; Magnetic anisotropy","Antiferromagnetic materials; Antiferromagnetism; Cobalt compounds; Crystallography; Damping; Ferromagnetic materials; Ferromagnetism; Hysteresis; Ion beams; Ion exchange; Iron; Linewidth; Magnesia; Magnetic anisotropy; Magnetic couplings; Magnetization; Magnetocrystalline anisotropy; Magnetometry; Sputtering; Temperature; Exchange bias; Ferromagnetic and anti-ferromagnetic; Ferromagnetic resonance (FMR); Gilbert damping parameter; Landau-Lifshitz-Gilbert equations; Magnetic tunneling junctions; Magnetocrystalline anisotropy constant; Vibrating sample magnetometry; Ferromagnetic resonance","","","","","TUBITAK, (112T857)","Acknowledgements The authors thank to Prof. H. Zabel and Prof. K. Westerholt for sample preparation. This work was partially supported by TUBITAK through the Project No. 112T857.","Gilabert A., Ann. Phys., 2, (1977); Bourgeois O., Frydman A., Dynes R.C., Phys. Rev. Lett., 88, (2002); Cespedes O., Ferreira M.S., Sanvito S., Kociak M., Coey J.M.D., J. Phys. Condens. 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Magn., 25, 8, pp. 2659-2663, (2012); Yilgin R., Oogane M., Ando Y., Miyazaki T., Gilbert damping constant in polycrystalline CO 2 MnSi Heusler alloy films , Journal of Magnetism and Magnetic Materials, 310, 2 SUPPL. PART 3, pp. 2322-2323, (2007); Stiles M.D., McMichael R.D., Phys. Rev. B, 63, (2001)","R. Topkaya; Department of Physics, Gebze Institute of Technology, 41400 Gebze Kocaeli, Turkey; email: rtopkaya@gyte.edu.tr","","Springer New York LLC","","","","","","15571939","","","","English","J Supercond Novel Magn","Article","Final","","Scopus","2-s2.0-84901634723" +"Parker G.J.; Hitchon W.N.G.","Parker, G.J. (7402344444); Hitchon, W.N.G. (8577094400)","7402344444; 8577094400","A kinetic theory of micromagnetic time evolution","2013","Physics Letters, Section A: General, Atomic and Solid State Physics","377","37","","2388","2392","4","5","10.1016/j.physleta.2013.06.030","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84883490782&doi=10.1016%2fj.physleta.2013.06.030&partnerID=40&md5=62f21c4a516e5cb02a8f80b2fc2b7db1","HGST, San Jose, CA 95135, 3904 Yueba Buena Rd., United States; Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States","Parker G.J., HGST, San Jose, CA 95135, 3904 Yueba Buena Rd., United States; Hitchon W.N.G., Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States","A semi-analytic description of recording media grains magnetization flipping in a magnetic field provides hysteresis loops, efficiently, with all parameters found by following orbits, and in close agreement with existing results. Integrating the Landau-Lifshitz-Gilbert (LLG) equations numerically gives the average energy diffusion coefficient DÏμ, energy loss rate aÏμ and the barrier height which must be overcome. These allow solution of the kinetic equation for the probability density f and the escape rate γ of a grain trapped in an energy well, as well as other, similar, very stiff systems. γ is used in Monte Carlo simulation of hysteresis. The essential physics governing the grains behavior is outlined. © 2013 The Authors.","Computation for stiff problems; Hysteresis loops; Kinetic theory; Micromagnetics; Transition rate","Energy dissipation; Hysteresis; Hysteresis loops; Integral equations; Intelligent systems; Kinetic theory; Kinetics; Magnetic materials; Monte Carlo methods; Analytic descriptions; Energy-loss rate; Kinetic equations; Landau-Lifshitz-Gilbert equations; Micromagnetics; Probability densities; Stiff problem; Transition rates; Computation theory","","","","","","","Heinonen O.G., Schreiber D.K., Petford-Long A.K., Micromagnetic modeling of spin-wave dynamics in exchange-biased permalloy disks, Phys. Rev. B, 76, (2007); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo G., Azzerboni B., A numerical solution of the magnetization reversal modeling in a permalloy thin film using fifth order Runge-Kutta method with adaptive step size control, Physica B, 403, pp. 464-468, (2008); Kim S.-K., Micromagnetic computer simulations of spin waves in nanometre-scale patterned magnetic elements, J. Phys. D, Appl. Phys., 43, (2010); Kanai Y., Saiki M., Hirasawa K., Tsukamomo T., Yoshida K., Landau-Lifshitz-Gilbert micromagnetic analysis of single-pole-type write head for perpendicular magnetic recording using full-fft program on pc cluster system, IEEE Trans. Magn., 44, (2008); Fidler J., Schrefl T., Scholz W., Suess D., Dittrich R., Kirschner M., Micromagnetic modelling - The current state of the art, J. Phys. D, Appl. Phys., 33, (2000); Fidler J., Schrefl T., Micromagnetic modelling and magnetization processes, J. Magn. Magn. Mater., 272, pp. 641-646, (2004); Berkov D.V., Miltat J., Spin-torque driven magnetization dynamics: Micromagnetic modeling, J. Magn. Magn. Mater., 320, pp. 1238-1259, (2008); Plumer M.L., Van Ek J., Weller D., The Physics of Ultra-High-Density Magnetic Recording, (2001); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, (1963); Coffey W.T., Crothers D.S.F., Dormann J.L., Geoghegan L.J., Kalmykov Yu.P., Waldron J.T., Wickstead A.W., Effect of an oblique magnetic field on the superparamagnetic relaxation time, Phys. Rev. B, 52, pp. 15951-15965, (1995); Scholtz W., Schrefl T., Fidler J., Micromagnetic simulation of thermally activated switching in fine particles, J. Magn. Magn. Mater., 403, pp. 296-304, (2008); Schratzberger J., Lee J., Fuger M., Fidler J., Fiedler G., Schrefl T., Suess D., Validation of the transition state theory with Langevin-dynamics simulations, J. Appl. Phys., 108, (2010); Xue J., Victora R.H., Micromagnetic predictions for thermally assisted reversal over long time scales, Appl. Phys. Lett., 77, pp. 3432-3434, (2000); Alpakov D.M., Visscher P.B., Spin-torque switching: Fokker-Planck rate calculation, Phys. Rev. B, 72, (2005); Scharfetter D.L., Gummel H.K., Large signal analysis of a silicon read diode oscillator, IEEE Trans. Electron Devices, 16, pp. 64-77, (1969)","G.J. Parker; HGST, San Jose, CA 95135, 3904 Yueba Buena Rd., United States; email: gregory.parker@hgst.com","","Elsevier B.V.","","","","","","03759601","","PYLAA","","English","Phys Lett Sect A Gen At Solid State Phys","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-84883490782" +"Tanaka H.; Nakamura K.; Ichinokura O.","Tanaka, Hideaki (55624472145); Nakamura, Kenji (55516112700); Ichinokura, Osamu (7003759274)","55624472145; 55516112700; 7003759274","Basic examination of magnetic circuit model incorporating micromagnetic simulation","2012","2012 International Conference on Renewable Energy Research and Applications, ICRERA 2012","","","6477450","","","","0","10.1109/ICRERA.2012.6477450","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84876110321&doi=10.1109%2fICRERA.2012.6477450&partnerID=40&md5=a5ce0525ff4f85484b77561545d8cba2","Graduate School of Engineering, Tohoku University, Sendai, Japan","Tanaka H., Graduate School of Engineering, Tohoku University, Sendai, Japan; Nakamura K., Graduate School of Engineering, Tohoku University, Sendai, Japan; Ichinokura O., Graduate School of Engineering, Tohoku University, Sendai, Japan","This paper presents a novel magnetic circuit model incorporating micromagnetic simulation. The proposed magnetic circuit model consists of two elements; one is a dc hysteresis element given by the micromagnetic simulation, the other is an inductance element which denotes eddy current loss in silicon steels. In addition, the proposed model can be coupled with an external electric circuit model. The validity of the proposed method is proved by comparing with catalog values. © 2012 IEEE.","hysteresis modeling; LLG equation; magnetic circuit model; micromagnetic simulation","Hysteresis; Magnetic circuits; Magnetic logic devices; Silicon steel; Eddy current-loss; Electric circuit model; Hysteresis element; Hysteresis modeling; LLG equation; Magnetic circuit model; Micromagnetic simulations; Circuit theory","","","","","","","Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the landau-lifshitz-gilbert equation for micromagnetics, Jpn.J.Appl.Phys, 28, pp. 2485-2087, (1989); Karapetoff V., The Magnetic Circuit, McGraw-Hill, (1911); Nakamura K., Ichinokura O., Operation analysis for electrical machinery based on reluctance network, IEEJ Transactions on Fundamentals and Materials, 126, pp. 150-156, (2006); Hayashi N., Saito K., Nakatani Y., Calculation of demagnetizing field distribution based on fast fourier transform of convolution, Jpn.J.Appl.Phys., 35, pp. 6065-6073, (1996); Lebecki K.M., Donahue M.J., Gutowski M.W., Periodic boundary conditions for demagnetization interactions in micromagnetic simulations, J.Phys.D,Appl.Phys, 41, (2008); Zhu J., Neal Bertram H., Micromagnetic studies of thin metallic films, J.Appl.Phys, 63, pp. 3248-3253, (1988)","","","","International Journal of Renewable Energy Research (IJRER)","1st International Conference on Renewable Energy Research and Applications, ICRERA 2012","11 November 2012 through 14 November 2012","Nagasaki","96529","","978-146732328-4","","","English","Int. Conf. Renew. Energy Res. Appl., ICRERA","Conference paper","Final","","Scopus","2-s2.0-84876110321" +"Bordianu A.; Ioniţ̌a V.; Petrescu L.","Bordianu, Adelina (55158138600); Ioniţ̌a, Valentin (6602276485); Petrescu, Lucian (16402894300)","55158138600; 6602276485; 16402894300","Micro-Scale numerical simulation of the magnetic recording","2012","Revue Roumaine des Sciences Techniques Serie Electrotechnique et Energetique","57","1","","3","9","6","1","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84871897755&partnerID=40&md5=425d153f39ba4540417ac1f168e0b722","Politehnica University of Bucharest, Bucharest, Spl. Independenţei 313, Romania","Bordianu A., Politehnica University of Bucharest, Bucharest, Spl. Independenţei 313, Romania; Ioniţ̌a V., Politehnica University of Bucharest, Bucharest, Spl. Independenţei 313, Romania; Petrescu L., Politehnica University of Bucharest, Bucharest, Spl. Independenţei 313, Romania","The paper presents the micro-scale numerical simulation of the longitudinal magnetic recording for a three layered structure, considering the quasi-static regime. The magnetization of the recording medium was calculated for different cases using the Landau-Lifshitz-Gilbert equation, implemented in Magsimus software.","Llg equation; Micro-scale magnetic characterization; Nanoparticles","","","","","","","","Gavrila H., Inregistrǎ;ri Magnetice, (2005); Denis Mee C., Eric D., Daniel, Magnetic Recording Technology, (1996); Gavrila H., Ionita V., Magnetic materials for advanced magnetic recording media, Journal of Optoelectronics and Advanced Materials, 5, 4, pp. 919-932, (2003); Oti J., Magsimus Deluxe - User Manual, (2009); Cimrak I., A survey on the numerics and computations for the landau-Lifshitz Equation of Micromagnetism, Archives Computational Methods in Engineering, 15, 3, pp. 277-309, (2008); Haseba Y., Et al., Recording process in high frequency field, IEEE Trans, on Magnetics, 35, (1999); Khan M., Victora R.H., Micromagnetic model of perpendicular recording head with soft underlayer, IEEE Trans, on Magnetics, 37, (2001); Kanai Y., Et al., Landau-lifshitz-gilbert micromagnetic analysis of single-pole-type write head for perpendicular magnetic recording using full-fft program on pc cluster system, IEEE Trans. on Magnetics, 44, (2008)","","","Editura Academiei Romane","","","","","","00354066","","","","English","Rev. Rom. Sci. Tech. Ser. Electrotech. Energ.","Article","Final","","Scopus","2-s2.0-84871897755" +"Daniel M.; Arun R.; Sabareesan P.","Daniel, M. (7202421120); Arun, R. (55433105300); Sabareesan, P. (35192369200)","7202421120; 55433105300; 35192369200","Impact of magnetic surface anisotropy on the precessional switching of magnetization in Pt-alloy nanofilms","2012","Physica B: Condensed Matter","407","17","","3352","3359","7","4","10.1016/j.physb.2012.04.037","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84862988039&doi=10.1016%2fj.physb.2012.04.037&partnerID=40&md5=98bc1f37373bacebf75240659e1088fb","Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India; Department of Material Sciences, S.N. Bose National Centre for Basic Sciences, Kolkata 700 098, India","Daniel M., Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India; Arun R., Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India; Sabareesan P., Department of Material Sciences, S.N. Bose National Centre for Basic Sciences, Kolkata 700 098, India","Precessional switching of magnetization in CoPt and FePt nanofilms is investigated by solving the Landau-Lifshitz-Gilbert (LLG) equation analytically and numerically. Switching in these films occurs only above a critical value of the magnetic field, and it further depends on the magnetocrystalline anisotropy and saturation magnetization of the film. The presence of magnetic surface anisotropy in these films reduces the switching time significantly. Also, the switching time in the case of Pt-alloys of Co and Fe is low compared to that in the case of pure Co and Fe films. © 2012 Elsevier B.V. All rights reserved.","Critical field for switching; Ferromagnetic nanofilms; Magnetization switching; Switching time","Cerium alloys; Magnetic anisotropy; Magnetic fields; Magnetocrystalline anisotropy; Platinum; Platinum alloys; Saturation magnetization; Critical fields; Critical value; Fe films; Landau-Lifshitz-Gilbert equations; Magnetic surfaces; Magnetization switching; Nano films; Precessional switching; Switching time; Switching","","","","","Bharathidasan University","The work of M.D. and R.A. forms part of a major DST project. P.S. thanks Bharathidasan University for financial support where major portion of the work has been carried out. ","Kryder M.H., Gage E.C., McDaniel T.W., Challener W.A., Rottmayer R.E., Ju G., Hsia Y.-T., Erden M.F., Proc. IEEE, 96, (2008); Spaldin N.A., Magnetic Materials: Fundamentals and Device Applications, (2003); Christodoulides J.A., Huang Y., Zhang Y., Hadjipanayis G.C., Panagiotopoulos I., Niarchos D., J. Appl. Phys., 87, (2000); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, (2000); Daquino M., Scholz W., Schrefl T., Serpico C., Fidler J., J. Appl. Phys., 95, (2004); Xiao Q.F., Rudge J., Choi B.C., Hong Y.K., Donohoe G., Phys. Rev. B, 73, (2006); Bauer M., Fassbender J., Hillebrands B., J. Appl. Phys., 87, (2000); Daniel M., Sabareesan P., J. Phys.: Condens. Matter, 21, (2009); Daniel M., Sabareesan P., J. Magn. Magn. Mater., 322, (2010); Sabareesan P., Daniel M., J. Phys.: Condens. Matter, 23, (2011); Gradmann U., J. Magn. Magn. Mater., 6, (1977); Brown Jr. W.F., Micromagnetics, (1963); Gradmann U., J. Magn. Magn. Mater., 100, (1991); Gradmann U., Handbook of Magnetic Materials, 7, (1993); Iunin Y.L., Kabanov Y.P., Nikitenko V.I., Cheng X.M., Chien C.L., Shapiro A.J., Shull R.D., J. Magn. Magn. Mater., 320, (2008); Heinrich B., Bland J.A.C., Ultrathin Magnetic Structures, 4, (2005); Charap S.H., Lu P.L., He Y., IEEE Trans. Magn., 33, (1997); Seki T., Mitani S., Yakushiji K., Takanashi K., J. Appl. Phys., 99, (2006); MacGuire R.A., Gaunt P., Philos. Mag., 13, (1966); Moriyama T., Mitani S., Seki T., Shima T., Takanashi K., Sakuma A., J. Appl. Phys., 95, (2004); Honolka J., Lee T.Y., Kuhnke K., Enders A., Skomski R., Bornemann S., Mankovsky S., Minar J., Staunton J., Phys. Rev. Lett., 102, (2009); Zhao Z.L., Ding J., Inaba K., Chen J.S., Wang J.P., Appl. Phys. Lett., 83, (2003); Weller D., Moser A., Folks L., Best M.E., Lee W., Toney M.F., Schwickert M., Thiele J.U., Doerner M.F., IEEE Trans. Mag., 36, (2000); Weller D., Moser A., IEEE. Trans. Magn., 35, (1999); Che R.C., Takeguchi M., Shimojo M., Zhang W., Furuya K., Appl. Phys. Lett., 87, (2005); Wang Y., Yang H., J. Am. Chem. Soc., 127, (2005); Lairson B.M., Visokay M.R., Marinero E.E., Sinclair R., Clemens B.M., J. Appl. Phys., 74, (1993); Yuan F.-T., Sun A.C., Mei J.-K., Liao W.M., Hsu J.-H., Lee H.Y., J. Appl. Phys., 109, (2011); Visokaya M.R., Sinclair R., Appl. Phys. Lett., 66, (1995); Maat S., Checkelsky J., Carey M.J., Katine J.A., Childress J.R., J. Appl. Phys., 98, (2005); Back C.H., Allenspach R., Weber W., Parkin S.S.P., Weller D., Garwin E.L., Siegmann H.C., Science, 285, (1999); Back C.H., Weller D., Heidmann J., Mauri D., Guarisco D., Garwin E.L., Siegmann H.C., Phys. Rev. Lett., 81, (1998); Siegmann H.C., Garwin E.L., Prescott C.Y., Heidmann J., Mauri D., Weller D., Allenspach R., Weber W., J. Magn. Magn. Mater., 151, (1995); Gerrits Th., Van Den Berg H.A.M., Hohlfeld J., Ba L., Rasing Th., Nature, 418, (2002); Gerrits Th., Hohlfeld J., Gielkens O., Veenstra K.J., Bal K., Rasing Th., J. Appl. Phys., 89, (2001); Stamm C., Tudosa I., Phys. Rev. Lett., 94, (1999); Schumacher H.W., Chappert C., Crozat P., Sousa R.C., Freitas P.P., Miltat J., Fassbender J., Hillebrands B., Phys. Rev. Lett., 90, (2003); Schumacher H.W., Chappert C., Sousa R.C., Freitas P.P., Miltat J., Phys. Rev. Lett., 90, (2003); Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002); Yu H., Granville S., Yu D.P., Ansermet J.-Ph., Phys. Rev. Lett., 104, (2010); Serrano-Guisan S., Rott K., Reiss G., Langer J., Ocker B., Schumacher H.W., Phys. Rev. Lett., 101, (2008); Garzon S., Ye L., Webb R.A., Crawford T.M., Covington M., Kaka S., Phys. Rev. B, 78, (2008); Seki T., Mitani S., Yakushiji K., Takanashi K., Appl. Phys. Lett., 88, (2006); Kim J.-W., Song H.-S., Jeong J.-W., Lee K.-D., Sohn J.-W., Shima T., Shin S.-C., Appl. Phys. Lett., 98, (2011); Mizukami S., Iihama S., Inami N., Hiratsuka T., Kim G., Naganuma H., Oogane M., Ando Y., Appl. Phys. Lett., 98, (2011); Valentin J., Kleinefeld Th., Weller D., J. Phys. D: Appl. Phys., 29, (1996); Alexandrakis V., Niarchos D., Wolff M., Panagiotopoulos I., J. Appl. Phys., 105, (2009)","M. Daniel; Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024, India; email: danielcnld@gmail.com","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-84862988039" +"Li Y.; Xu K.; Hu S.; Suter J.; Schreiber D.K.; Ramuhalli P.; Johnson B.R.; McCloy J.","Li, Yulan (55894830800); Xu, Ke (56719984900); Hu, Shenyang (25632233200); Suter, Jon (14039713700); Schreiber, Daniel K. (22635599200); Ramuhalli, Pradeep (6602239412); Johnson, Bradley R. (57193265226); McCloy, John (22951405100)","55894830800; 56719984900; 25632233200; 14039713700; 22635599200; 6602239412; 57193265226; 22951405100","Computational and experimental investigations of magnetic domain structures in patterned magnetic thin films","2015","Journal of Physics D: Applied Physics","48","30","305001","","","","12","10.1088/0022-3727/48/30/305001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84937022259&doi=10.1088%2f0022-3727%2f48%2f30%2f305001&partnerID=40&md5=1059134c698d10b2d001e6235ea01d32","Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; School of Mechanical and Materials Engineering, Materials Science and Engineering Program, Washington State University, PO BOX 642920, Pullman, 99164, WA, United States","Li Y., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; Xu K., School of Mechanical and Materials Engineering, Materials Science and Engineering Program, Washington State University, PO BOX 642920, Pullman, 99164, WA, United States; Hu S., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; Suter J., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; Schreiber D.K., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; Ramuhalli P., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; Johnson B.R., Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, 99352, WA, United States; McCloy J., School of Mechanical and Materials Engineering, Materials Science and Engineering Program, Washington State University, PO BOX 642920, Pullman, 99164, WA, United States","The use of nondestructive magnetic signatures for continuous monitoring of the degradation of structural materials in nuclear reactors is a promising yet challenging application for advanced functional materials behavior modeling and measurement. In this work, a numerical model, which is based on the Landau-Lifshitz-Gilbert equation of magnetization dynamics and the phase field approach, was developed to study the impact of defects such as nonmagnetic precipitates and/or voids, free surfaces and crystal orientation on magnetic domain structures and magnetic responses in magnetic materials, with the goal of exploring the correlation between microstructures and magnetic signatures. To validate the model, single crystal iron thin films (∼240 nm thickness) were grown on MgO substrates and a focused ion beam was used to pattern micrometer-scale specimens with different geometries. Magnetic force microscopy (MFM) was used to measure magnetic domain structure and its field-dependence. Numerical simulations were constructed with the same geometry as the patterned specimens and under similar applied magnetic field conditions as tested by MFM. The results from simulations and experiments show that 1) magnetic domain structures strongly depend on the film geometry and the external applied field and 2) the predicted magnetic domain structures from the simulations agree quantitatively with those measured by MFM. The results demonstrate the capability of the developed model, used together with key experiments, for improving the understanding of the signal physics in magnetic sensing, thereby providing guidance to the development of advanced nondestructive magnetic techniques. © 2015 IOP Publishing Ltd.","iron thin films; LLG equation; magnetic force microscopy; nondestructive magnetic signatures; phase field approach","Crystal orientation; Crystallography; Functional materials; Geometry; Ion beams; Magnetic fields; Magnetic force microscopy; Magnetic materials; Magnetic structure; Magnetic thin films; Magnetism; Magnetization; Nondestructive examination; Nuclear reactors; Numerical models; Single crystals; Thickness measurement; Thin films; Applied magnetic fields; Experimental investigations; Iron thin films; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic force microscopies (MFM); Magnetic signatures; Phase-field approaches; Magnetic domains","","","","","U.S. Department of Energy, (DE-AC05-76RL01830)","","Kamada Y., Watanabe H., Mitani S., Mohapatra J.N., Kikuchi H., Kobayashi S., Mizuguchi M., Takanashi K., J. Nucl. Mater., 442, (2013); Kobayashi S., Tsukidate S., Kamada Y., Kikuchi H., Ohtani T., J. Magn. Magn. Mater., 324, (2012); Kempf R.A., Sacanell J., Milano J., Guerra Mendez N., Winkler E., Butera A., Troiani H., Saleta M.E., Fortis A.M., J. Nucl. Mater., 445, (2014); Lo C.C.H., AIP Conf. Proc., 1430, (2012); Gussev M.N., Busby J.T., Tan L., Garner F.A., J. Nucl. Mater., 448, (2014); Park D.G., Hong J.H., Kim I.S., Kim H.C., J. Mater. Sci., 32, (1997); Mohapatra J.N., Kamada Y., Kikuchi H., Kobayashi S., Echigoya J., Park D.G., Cheong Y.M., IEEE T. Magn., 47, (2011); Henager C.H., McCloy J.S., Ramuhalli P., Edwards D.J., Hu S., Li Y., Acta Mater., 61, (2013); Takaya S., Suzuki T., Matsumoto Y., Demachi K., Uesaka M., J. Nucl. Mater., 327, (2004); Batista L., Rabe U., Hirsekorn S., NDT e Int., 57, (2013); Ramuhalli P., Henager C.H., Griffin J.W., Meyer R.M., Coble J.B., Pitman S.G., Bond S.G., 3rd Int. Conf. on NPP Life Management (PLIM) for Long Term Operations (LTO), (2012); Hu S.Y., Li Y.L., McCloy J., Montgomery R., Henager C.H., IEEE Magn. Lett., 4, (2013); Hubert A., Schaefer R., Magnetic Domains: The Analysis of Magnetic Microstructures, (1998); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Zhang J.X., Chen L.Q., Acta Mater., 53, (2005); Chen L.Q., Ann. Rev. Mater. Res., 32, (2002); Zubov V.E., Krinchik G.S., Kudakov A.D., Sov. Phys. JETP, 67, (1988); Schneider M., Mullerpfeiffer S., Zinn W., J. Appl. Phys., 79, (1996); Zueco E., Rave W., Schafer R., Mertig M., Schultz L., J. Magn. Magn. Mater., 196, (1999); Yu J., Rudiger U., Kent A.D., Thomas L., Parkin S.S.P., Phys. Rev., 60, (1999); Hothersall D.C., J. Phys., 3, 5, (1970); Aharoni A., Jakubovics J.P., IEEE Trans. Magn., 26, (1990); Aharoni A., Jakubovics J.P., Phys. Rev., 43, (1991); Huo S., Bishop J.E.L., Tucker J.W., J Appl. Phys., 81, (1997); Huo S., Bishop J.E.L., Tucker J.W., Rainforth W.M., Davies H.A., IEEE Trans. Magn., 33, (1997); Huo S., Bishop J.E.L., Tucker J.W., Rainforth W.M., Davies H.A., IEEE Trans. Magn., 33, (1997); Huo S., Bishop J.E.L., Tucker J.W., Rainforth W.M., Davies H.A., J. Magn. Magn. Mater., 177, (1998); Huo S., Bishop J.E.L., Tucker J.W., Rainforth W.M., Davies H.A., J. Magn. Magn. Mater., 177, (1998); Wang X.P., Wang K., N E.W., Discrete Contin. Dyn. Syst. Ser., 6, (2006); Suter J.D., Ramuhalli P., McCloy J.S., Xu K., Hu S.Y., Li Y.L., Edwards D.J., Schemer-Kohrn A.L., Johnson B., Meso-Scale magnetic signatures for nuclear reactor steel irradiation embrittlement monitoring, Proc. AIP Conf. Proc., 1650, (2015); Bertotti G., Hysteresis in Magnetism: For Physicists, Materials Scientists, and Engineers, (1998); Wang X.P., Garcia-Cervera C.J., N E.W., J. Comput. Phys., 171, (2001); Xu S., Dunlop D.J., Geophys. Res. Lett., 23, (1996); Lilley B.A., Phil. Mag., 41, (1950)","Y. Li; Pacific Northwest National Laboratory, Richland, 902 Battelle Boulevard, 99352, United States; email: yulan.li@pnnl.gov","","Institute of Physics Publishing","","","","","","00223727","","JPAPB","","English","J Phys D","Article","Final","","Scopus","2-s2.0-84937022259" +"Wen S.L.; Liu Y.; Zhao X.C.; Fan Z.Z.","Wen, S.L. (55638392400); Liu, Y. (55899847200); Zhao, X.C. (8216616800); Fan, Z.Z. (56544941900)","55638392400; 55899847200; 8216616800; 56544941900","Synthesis, permeability resonance and microwave absorption of flake-assembled cobalt superstructure","2015","Journal of Magnetism and Magnetic Materials","385","","","182","187","5","28","10.1016/j.jmmm.2015.03.027","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84924580979&doi=10.1016%2fj.jmmm.2015.03.027&partnerID=40&md5=3b5a5c61828d993f374baa655e1803d1","School of Materials Science and Engineering, Beijing Institute of Technology, China; AVIC Beijing Institute of Aeronautical Materials, Beijing 100081, China","Wen S.L., School of Materials Science and Engineering, Beijing Institute of Technology, China; Liu Y., School of Materials Science and Engineering, Beijing Institute of Technology, China; Zhao X.C., School of Materials Science and Engineering, Beijing Institute of Technology, China; Fan Z.Z., AVIC Beijing Institute of Aeronautical Materials, Beijing 100081, China","To meet the demands of high-efficient microwave absorption materials, cobalt superstructure was synthesized and characterized. As SEM confirmed, the cobalt superstructure was assembled by flakes. The size of cobalt superstructure was about 10 μm, and the thickness of the flake was about 500 nm. The permittivity and permeability were investigated as a function of frequency in the microwave range of 1-18 GHz. Based on the LLG equation and exchange resonance mode, three magnetic resonances, including one natural resonance and two exchange resonances were discussed. The calculated reflection loss (RL) indicated the cobalt superstructure indicated the cobalt superstructure has potential application as a promising candidate for microwave absorption. The maximum RL reached as high as -77.29 dB with a matching thickness of 1.5 mm, and the effective bandwidth with a reflection loss less than -10 dB was 3.6 GHz from 9.85 to 13.45 GHz. For cobalt superstructure, magnetic loss mainly contributed even more than dielectric loss to the microwave absorption. ©2015 Elsevier B.V. All rights reserved.","Cobalt superstructure; Microwave absorption; Permeability; Permittivity","Dielectric losses; Magnetic resonance; Mechanical permeability; Microwaves; Permittivity; Resonance; Effective bandwidth; Function of frequency; High efficient; Microwave absorption; Microwave absorption materials; Natural resonance; Reflection loss; Resonance mode; Cobalt","","","","","","","Liu J., Cheng J., Che R., Xu J., Liu M., Liu Z., Synthesis and microwave absorption properties of yolk-shell microspheres with magnetic iron oxide cores and hierarchical copper silicate shells, ACS Appl. Mater. Interfaces, 5, pp. 2503-2509, (2013); Wang L., Huang Y., Sun X., Huang H., Liu P., Synthesis and microwave absorption enhancement of graphene@ Fe3O4@ SiO2@ NiO nanosheets hierarchical structures, Nanoscale, 6, pp. 3157-3164, (2014); Liu T., Pang Y., Zhu M., Kobayashi S., Microporous Co@CoO nanoparticles with superior microwave absorption properties, Nanoscale, 6, pp. 2447-2454, (2014); Jiang J., Li D., Geng D., An J., He J., Liu W., Zhang Z., Microwave absorption properties of core double-shell FeCo/C/BaTiO3 nanocomposites, Nanoscale, 6, pp. 3967-3971, (2014); Phuoc N.N., Chapon P., Acher O., Ong C., Large magneto-elastic anisotropy enhancement with temperature in composition-graded FeCoTa thin films, J. Appl. Phys., 114, (2013); Wu Y., Han M., Tang Z., Deng L., Eddy current effect on the microwave permeability of Fe-based nanocrystalline flakes with different sizes, J. Appl. Phys., 115, (2014); Chen M., Zhu Y., Pan Y., Kou H., Xu H., Guo J., Gradient multilayer structural design of CNTs/SiO2 composites for improving microwave absorbing properties, Mater. Des., 32, pp. 3013-3016, (2011); Zhang X., Guan P., Dong X., Multidielectric polarizations in the core/shell Co/graphite nanoparticles, Appl. Phys. Lett., 96, (2010); Tang X., Tian Q., Zhao B., Hu K., The microwave electromagnetic and absorption properties of some porous iron powders, Mater. Sci. Eng.: A, 445, pp. 135-140, (2007); Zhang X., Dong X., Huang H., Liu Y., Wang W., Zhu X., Lv B., Lei J., Lee C., Microwave absorption properties of the carbon-coated nickel nanocapsules, Appl. Phys. Lett., 89, (2006); Jiang J., Li X., Han Z., Li D., Wang Z., Geng D., Ma S., Liu W., Zhang Z., Disorder-modulated microwave absorption properties of carbon-coated FeCo nanocapsules, J. Appl. Phys., 115, (2014); Wang H., Dai Y., Gong W., Geng D., Ma S., Li D., Liu W., Zhang Z., Broadband microwave absorption of CoNi@C nanocapsules enhanced by dual dielectric relaxation and multiple magnetic resonances, Appl. Phys. Lett., 102, (2013); Karimpoor A., Erb U., Aust K., Palumbo G., High strength nanocrystalline cobalt with high tensile ductility, Scr. Mater., 49, pp. 651-656, (2003); Sort J., Nogues J., Surinach S., Munoz J., Baro M., Correlation between stacking fault formation, allotropic phase transformations and magnetic properties of ball-milled cobalt, Mater. Sci. Eng.: A, 375, pp. 869-873, (2004); Sort J., Nogues J., Surinach S., Baro M., Microstructural aspects of the hcp-fcc allotropic phase transformation induced in cobalt by ball milling, Philos. Mag., 83, pp. 439-455, (2003); Halsey T.C., Duplantier B., Honda K., Multifractal dimensions and their fluctuations in diffusion-limited aggregation, Phys. Rev. Lett., 78, (1997); Liu X., Yi R., Wang Y., Qiu G., Zhang N., Li X., Highly ordered snowflakelike metallic cobalt microcrystals, J. Phys. Chem. C, 111, pp. 163-167, (2007); Tong G., Yuan J., Wu W., Hu Q., Qian H., Li L., Shen J., Flower-like Co superstructures: Morphology and phase evolution mechanism and novel microwave electromagnetic characteristics, CrystEngComm, 14, pp. 2071-2079, (2012); Verma A., Saxena A., Dube D., Microwave permittivity and permeability of ferrite-polymer thick films, J. Magn. Magn. Mater., 263, pp. 228-234, (2003); Bayrakdar H., Complex permittivity, complex permeability and microwave absorption properties of ferrite-paraffin polymer composites, J. Magn. Magn. Mater., 323, pp. 1882-1885, (2011); Li Z., Deng Y., Shen B., Hu W., Preparation and microwave absorption properties of Ni-Fe3O4 hollow spheres, Mater. Sci. Eng.: B, 164, pp. 112-115, (2009); Wen F., Zhang F., Xiang J., Hu W., Yuan S., Liu Z., Microwave absorption properties of multiwalled carbon nanotube/FeNi nanopowders as light-weight microwave absorbers, J. Magn. Magn. Mater., 343, pp. 281-285, (2013); Tong G., Liu F., Wu W., Du F., Guan J., Rambutan-like Ni/MWCNT heterostructures: Easy synthesis, formation mechanism, and controlled static magnetic and microwave electromagnetic characteristics, J. Mater. Chem. A, 2, pp. 7373-7382, (2014); Deng L., Zhou P., Xie J., Zhang L., Characterization and microwave resonance in nanocrystalline FeCoNi flake composite, J. Appl. Phys., 101, (2007); Toneguzzo P., Viau G., Acher O., Guillet F., Bruneton E., Fievet-Vincent F., Fievet F., CoNi and FeCoNi fine particles prepared by the polyol process: Physico-chemical characterization and dynamic magnetic properties, J. Mater. Sci., 35, pp. 3767-3784, (2000); Ma F., Qin Y., Li Y.-Z., Enhanced microwave performance of cobalt nanoflakes with strong shape anisotropy, Appl. Phys. Lett., 96, (2010); Kittel C., On the theory of ferromagnetic resonance absorption, Phys. Rev., 73, (1948); Polder D., Smit J., Resonance phenomena in ferrites, Rev. Mod. Phys., 25, (1953); Aharoni A., Magnetostatic energy calculations, IEEE Trans. Magn., 27, pp. 3539-3547, (1991); Toneguzzo P., Acher O., Viau G., Pierrard A., Fievet-Vincent F., Fievet F., Rosenman I., Static and dynamic magnetic properties of fine CoNi and FeCoNi particles synthesized by the polyol process, IEEE Trans. Magn., 35, pp. 3469-3471, (1999); Li J., Huang J., Qin Y., Ma F., Magnetic and microwave properties of cobalt nanoplatelets, Mater. Sci. Eng.: B, 138, pp. 199-204, (2007); Shi X.-L., Cao M.-S., Yuan J., Fang X.-Y., Dual nonlinear dielectric resonance and nesting microwave absorption peaks of hollow cobalt nanochains composites with negative permeability, Appl. Phys. Lett., 95, (2009); Kim S., Jo S., Gueon K., Choi K., Kim J., Churn K., Complex permeability and permittivity and microwave absorption of ferrite-rubber composite at X-band frequencies, IEEE Trans. Magn., 27, pp. 5462-5464, (1991); Che R., Peng L.M., Duan X.F., Chen Q., Liang X., Microwave absorption enhancement and complex permittivity and permeability of Fe encapsulated within carbon nanotubes, Adv. Mater., 16, pp. 401-405, (2004); Wang T., Liu Z., Lu M., Wen B., Ouyang Q., Chen Y., Zhu C., Gao P., Li C., Cao M., Graphene-Fe3O4 nanohybrids: Synthesis and excellent electromagnetic absorption properties, J. Appl. Phys., 113, (2013); Sun G., Dong B., Cao M., Wei B., Hu C., Hierarchical dendrite-like magnetic materials of Fe3O4, γ-Fe2O3, and Fe with high performance of microwave absorption, Chem. Mater., 23, pp. 1587-1593, (2011); Fu L.-S., Jiang J.-T., Xu C.-Y., Zhen L., Synthesis of hexagonal Fe microflakes with excellent microwave absorption performance, CrystEngComm, 14, pp. 6827-6832, (2012); Wu R., Zhou K., Yang Z., Qian X., Wei J., Liu L., Huang Y., Kong L., Wang L., Molten-salt-mediated synthesis of SiC nanowires for microwave absorption applications, CrystEngComm, 15, pp. 570-576, (2013); Wang L., Huang Y., Ding X., Liu P., Zong M., Synthesis and microwave absorption enhancement of NiO nanosheets@SiO2@ graphene hierarchical structures, RSC Adv., 3, pp. 23290-23295, (2013); Zhan X., Tang H., Du Y., Talbi A., Zha J., He J., Facile preparation of Fe nanochains and their electromagnetic properties, RSC Adv., 3, pp. 15966-15970, (2013); Qi X., Deng Y., Zhong W., Yang Y., Qin C., Au C., Du Y., Controllable and large-scale synthesis of carbon nanofibers, bamboo-like nanotubes, and chains of nanospheres over Fe/SnO2 and their microwave-absorption properties, J. Phys. Chem. C, 114, pp. 808-814, (2009)","","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84924580979" +"Bruckner F.; Suess D.; Feischl M.; Führer T.; Goldenits P.; Page M.; Praetorius D.; Ruggeri M.","Bruckner, F. (44561022400); Suess, D. (7004076065); Feischl, M. (52363525000); Führer, T. (55922785100); Goldenits, P. (37064726800); Page, M. (55597570300); Praetorius, D. (6507452481); Ruggeri, M. (56196953600)","44561022400; 7004076065; 52363525000; 55922785100; 37064726800; 55597570300; 6507452481; 56196953600","Multiscale modeling in micromagnetics: Existence of solutions and numerical integration","2014","Mathematical Models and Methods in Applied Sciences","24","13","","2627","2662","35","29","10.1142/S0218202514500328","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84929606146&doi=10.1142%2fS0218202514500328&partnerID=40&md5=f19b278723e793b95e927a3c8caab271","Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria","Bruckner F., Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Suess D., Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Feischl M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Führer T., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Goldenits P., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Page M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Praetorius D., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria; Ruggeri M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Vienna, 1040, Austria","Various applications ranging from spintronic devices, giant magnetoresistance sensors, and magnetic storage devices, include magnetic parts on very different length scales. Since the consideration of the Landau-Lifshitz-Gilbert equation (LLG) constrains the maximum element size to the exchange length within the media, it is numerically not attractive to simulate macroscopic parts with this approach. On the other hand, the magnetostatic Maxwell equations do not constrain the element size, but cannot describe the short-range exchange interaction accurately. A combination of both methods allows one to describe magnetic domains within the micromagnetic regime by use of LLG and also considers the macroscopic parts by a nonlinear material law using the Maxwell equations. In our work, we prove that under certain assumptions on the nonlinear material law, this multiscale version of LLG admits weak solutions. Our proof is constructive in the sense that we provide a linear-implicit numerical integrator for the multiscale model such that the numerically computable finite element solutions admit weak H1-convergence (at least for a subsequence) towards a weak solution. © 2014 World Scientific Publishing Company.","FEM-BEM coupling; Finite elements; Landau-Lifshitz-Gilbert equation; Micromagnetics; Multiscale model","Finite element method; Giant magnetoresistance; Magnetic domains; Magnetic storage; Nonlinear equations; Virtual storage; FEM-BEM coupling; Finite element solution; Landau-Lifshitz-Gilbert equations; Magnetoresistance sensors; Micromagnetics; Multi-scale Modeling; Non-linear material law; Short-range exchange interaction; Maxwell equations","","","","","Vienna Science and Technology Fund, WWTF, (MA09-029); Austrian Science Fund, FWF, (P21732, SFB-ViCoM F4112-N13, W1245); Technische Universität Wien","The authors acknowledge financial support through the WWTF project MA09-029, the FWF project P21732, the FWF project SFB-ViCoM F4112-N13, the FWF graduate school W1245, and the innovative projects initiative of Vienna University of Technology.","Alouges F., A new finite element scheme for Landau-Lifshitz equations, Discrete Contin. Dynam. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Kritsikis E., Toussaint J.-C., A convergent finite element approximation for Landau-Lifshitz-Gilbert equation, Physica B, 407, pp. 1345-1349, (2012); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Aurada M., Feischl M., Fuhrer T., Karkulik M., Melenk J.M., Praetorius D., Classical FEM-BEM coupling methods: Nonlinearities, well-posedness, and adaptivity, Comput. Mech., 51, pp. 399-419, (2013); Aurada M., Feischl M., Fuhrer T., Karkulik M., Praetorius D., Energy norm-based error estimators for adaptive BEM for hypersingular integral equations, Appl. Numer. Math., (2014); Aurada M., Feischl M., Kemetmuller J., Page M., Praetorius D., Each H1/2-stable projection yields convergence and quasi-optimality of adaptive FEM with inhomogeneous Dirichlet data in Rd, M2AN Math. Model. Numer. Anal., 47, pp. 1207-1235, (2013); Banes L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 46, pp. 1399-1422, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 44, pp. 1405-1419, (2006); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comput., 77, pp. 773-788, (2008); Bergh J., Lofstrom J., Interpolation Spaces. An Introduction, (1976); Bruckner F., Vogler C., Bergmair B., Huber T., Fuger M., Suess D., Feischl M., Fuhrer T., Page M., Praetorius D., Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations, J. Magn. Magn. Mater., 343, pp. 163-168, (2013); Carstensen C., Praetorius D., Averaging techniques for the effective numerical solution of Symm's integral equation of the first kind, SIAM J. Sci. Comput., 27, pp. 1226-1260, (2006); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Methods Engrg., 15, pp. 277-309, (2008); Feischl M., Karkulik M., Melenk M., Praetorius D., Quasi-optimal convergence rate for an adaptive boundary element method, SIAM J. Numer. Anal., 51, pp. 1327-1348, (2013); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetizing fields, IEEE Trans. Magn., 26, pp. 415-417, (1990); Garcia-Cervera C.J., Numerical micromagnetics: A review, Bol. Soc. Esp. Mat. Apl. SeMA, 39, pp. 103-135, (2007); Garcia-Cervera C.J., Roma A., Adaptive mesh refinement for micromagnetics simulations, IEEE Trans. Magn., 42, pp. 1648-1654, (2006); Goldenits P., Konvergente Numerische Integration der Landau-Lifshitz-gilbert Gleichung, (2012); Goldenits P., Hrkac G., Mayr M., Praetorius D., Suess D., An effective integrator for the Landau-Lifshitz-Gilbert equation, Proc. Mathmod 2012 Conference; Goldenits P., Praetorius D., Suess D., Convergent geometric integrator for the Landau-Lifshitz-Gilbert equation in micromagnetics, Proc. Appl. Math. Mech., 11, pp. 775-776, (2011); Hsiao G., Wendland W., Boundary Integral Equations, 164, (2008); Hubert A., Schafer R., Magnetic Domains. The Analysis of Magnetic Microstructures, (1998); Johnson C., Nedelec J.-C., On the coupling of boundary integral and finite element methods, Math. Comput., 35, pp. 1063-1079, (1980); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev., 48, pp. 439-483, (2006); McLean W., Strongly Elliptic Systems and Boundary Integral Equations, (2000); Monk P., Finite Element Methods for Maxwell's Equations, (2003); Praetorius D., Analysis of the operator Δ-1 div arising in magnetic models, Z. Anal. Anwend., 23, pp. 589-605, (2004); Prohl A., Computational Micromagnetism, (2001); Rivas J., Zamarro J.M., Martin E., Pereira C., Simple approximation for magnetization curves and hysteresis loops, IEEE Trans. Magn., 17, pp. 1498-1502, (1981); Sauter S., Schwab C., Boundary Element Methods, (2011); Sayas F.-J., The validity of Johnson-Nédélec's BEM-FEM coupling on polygonal interfaces, SIAM J. Numer. Anal., 47, pp. 3451-3463, (2009); Scott L.R., Zhang S., Finite element interpolation of nonsmooth functions satisfying boundary conditions, Math. Comput., 54, pp. 483-493, (1990); Steinbach O., Numerical Approximation Methods for Elliptic Boundary Value Problems: Finite and Boundary Elements, (2008); Thomee V., Galerkin Finite Element Methods for Parabolic Problems, (2006); Verfurth R., A Review of a Posteriori Error Estimation and Adaptive Mesh-refinement Techniques, (1996); Zeidler E., Nonlinear Functional Analysis and its Applications, Part II/B, (1990)","","","World Scientific","","","","","","02182025","","","","English","Math. Models Methods Appl. Sci.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84929606146" +"Bottauscio O.; Fiorillo F.; Beatrice C.; Caprile A.; Magni A.","Bottauscio, Oriano (7006218126); Fiorillo, Fausto (7006013405); Beatrice, Cinzia (7004523868); Caprile, Ambra (37260980300); Magni, Alessandro (7007060492)","7006218126; 7006013405; 7004523868; 37260980300; 7007060492","Modeling high-frequency magnetic losses in transverse anisotropy amorphous ribbons","2015","IEEE Transactions on Magnetics","51","3","7093395","","","","16","10.1109/TMAG.2014.2361534","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84928713501&doi=10.1109%2fTMAG.2014.2361534&partnerID=40&md5=d45ef33fd4fb5a4bb57d7dfca068dc80","Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy","Bottauscio O., Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy; Fiorillo F., Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy; Beatrice C., Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy; Caprile A., Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy; Magni A., Istituto Nazionale di Ricerca Metrologica, Torino, 10135, Italy","The superior high-frequency magnetic behavior of transverse anisotropy amorphous ribbons can be qualitatively interpreted in terms of rotation dominated magnetization process and quantitatively predicted describing the spin dynamics by the Landau-Lifshitz-Gilbert (LLG) equation in association with the electromagnetic diffusion equation. The theory is applied to comprehensive measurements performed on Co-based alloys, tested as field-annealed tapewound rings from dc to 1 GHz with combination of fluxmetric and transmission line methods. The LLG equation is numerically solved considering the role of magnetostatic, exchange, anisotropy, eddy current, and applied fields. It accurately describes the high-frequency energy losses, ensuing from eddy currents, and spin damping. By further considering the low-frequency domain wall contribution, a full scenario for the broadband losses is achieved. © 2015 IEEE.","Amorphous alloys; high-frequency magnetic properties; Landau-Lifshitz-Gilbert (LLG) equation; magnetic losses","Anisotropy; Eddy currents; Electric lines; Energy dissipation; Frequency domain analysis; Magnetic leakage; Magnetism; Magnetization; Spin dynamics; Comprehensive measurement; Diffusion equations; High frequency HF; Landau-Lifshitz-Gilbert equations; Low frequency domain; Magnetic behavior; Transmission line methods; Transverse anisotropy; Amorphous alloys","","","","","","","Fiorillo F., Ferrara E., Coisson M., Beatrice C., Banu N., Magnetic properties of soft ferrites and amorphous ribbons up to radiofrequencies, J. Magn. Magn. Mater., 322, 9-12, pp. 1497-1504, (2010); Herzer G., Buschow K.H.L., Nanocrystalline soft magnetic alloys, Handbook of Magnetic Materials, 10, (1997); Flohrer S., Et al., Dynamic magnetization process of nanocrystalline tape wound cores with transverse field-induced anisotropy, Acta Mater., 54, 18, pp. 4693-4698, (2006); Magni A., Beatrice C., Bottauscio O., Caprile A., Ferrara E., Fiorillo F., Magnetization process in thin laminations up to 1 GHz, IEEE Trans. Magn., 48, 4, pp. 1363-1366, (2012); Magni A., Fiorillo F., Ferrara E., Caprile A., Bottauscio O., Beatrice C., Domain wall processes, rotations, and high-frequency losses in thin laminations, IEEE Trans. Magn., 48, 11, pp. 3796-3799, (2012); Ament W.S., Rado G.T., Electromagnetic effects of spin wave resonance in ferromagnetic metals, Phys. Rev., 97, 6, pp. 1558-1566, (1955); Serpico C., Mayergoyz I.D., Bertotti G., Analysis of eddy currents with Landau-Lifshitz equation as a constitutive relation, IEEE Trans. Magn., 37, 5, pp. 3546-3549, (2001); Dupre L., Olyslagerb F., Melkebeek J., Macroscopic fields in thin ferromagnetic sheets taking into account eddy currents and Landau-Lifshitz magnetization, J. Magn. Magn. Mater., 272-276, pp. 717-719, (2004); Slodicka M., Banas L., A numerical scheme for a Maxwell-Landau-Lifshitz-Gilbert system, Appl. Math. Comput., 158, 1, pp. 79-99, (2004); Le K.-N., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz-Gilbert equations, Comput. Math. Appl., 66, 8, pp. 1389-1402, (2013); Bottauscio O., Manzin A., Efficiency of the geometric integration of Landau-Lifshitz-Gilbert equation based on Cayley transform, IEEE Trans. Magn., 47, 5, pp. 1154-1157, (2011); Lewis D., Nigam N., Geometric integration on spheres and some interesting applications, J. Comput. Appl. Math., 151, 1, pp. 141-170, (2003); Magni A., Bottauscio O., Caprile A., Celegato F., Ferrara E., Fiorillo F., Spin precession by pulsed inductive magnetometry in thin amorphous plates, J. Appl. Phys., 115, 17, (2014)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84928713501" +"Choi W.H.; Kim J.; Ahmed I.; Kim C.H.","Choi, Won Ho (55556234200); Kim, Jongyeon (56252031500); Ahmed, Ibrahim (57196854706); Kim, Chris H. (8325011400)","55556234200; 56252031500; 57196854706; 8325011400","A comprehensive study on interface perpendicular MTJ variability","2015","Device Research Conference - Conference Digest, DRC","2015-August","","7175569","89","90","1","2","10.1109/DRC.2015.7175569","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84957681652&doi=10.1109%2fDRC.2015.7175569&partnerID=40&md5=090c34cac918aa3d5c56260d6b512b30","Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States","Choi W.H., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Kim J., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Ahmed I., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States; Kim C.H., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States","Spin transfer torque MRAM (STT-MRAM) is one of the promising candidates as a scalable nonvolatile memory with high density, and CMOS compatibility [1], [2]. Interface perpendicular magnetic tunnel junction (PMTJ) shown in Fig. 1 has been demonstrated with the goal of reducing the switching current while maintaining sufficient nonvolatility [3]. However, previous studies report that PMTJ suffers from process-dependent dimensional variations, thus it remains one of the major constrains in achieving high performance STT-MRAM [4, 5]. As shown in the equations of Fig. 1, the anisotropy field (HK) and free layer volume (V) are functions of PMTJ dimensions, hence their variations result in variation of STT switching characteristics such as thermal stability factor (Δ) and switching current (IC). The HK of PMTJ has a strong dependency on relative ratio between the free layer thickness (tF) and the critical thickness (tC) [3]. The equations of Fig. 1 suggest that the tF variation differently affects the PMTJ dimension-dependent parameters (gray circles), resulting in either increasing or decreasing Δ and/or IC. This paper presents a comprehensive study on process-dependent dimensional variability of PMTJ, especially focusing on estimating the impact of tF variation on Δ and IC variability. For a practical analysis, our physics-based macrospin SPICE model [7] captures the key physics of STT switching in PMTJ by incorporating all of the above mentioned PMTJ dimension-dependent parameters into the Landau-Lifshitz-Gilbert (LLG) equation. © 2015 IEEE.","Electronic mail; Integrated circuits; Switches","Electric switches; Electronic mail; Integrated circuits; Magnetic recording; MRAM devices; Switches; Switching; Tunnel junctions; Critical thickness; Dimensional variations; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Non-volatile memory; Spin transfer torque; Switching characteristics; Switching currents; Magnetic devices","","","","","","","Wolf S., Et al., Proc. IEEE, pp. 2155-2168, (2010); Lee K., Et al., Trans. Magn., pp. 131-136, (2011); Ikeda S., Et al., Nature Mater, pp. 721-724, (2011); Sato H., Et al., APL, (2011); Tsunoda K., Et al., IEDM, (2014); Hayakawa J., Et al., Jpn. JAP, pp. L587-L589, (2005); Kim J., Et al., DRC, (2014); Chun K.C., Et al., JSSC, pp. 2240-2243, (2013); Zhao H., Et al., JAP, (2011); Hofmann K., Et al., VLSI Tech. Symp., (2014)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Electron Devices Society (EDS)","73rd Annual Device Research Conference, DRC 2015","21 June 2015 through 24 June 2015","Columbus","117057","15483770","978-146738134-5","","","English","Dev. Res. Conf. Conf. Dig.","Conference paper","Final","","Scopus","2-s2.0-84957681652" +"Muroga S.; Asazuma Y.; Yamaguchi M.","Muroga, Sho (35111642100); Asazuma, Yuki (55430794500); Yamaguchi, Masahiro (55541020100)","35111642100; 55430794500; 55541020100","Study of FMR frequency shift through electromagnetic simulation and its application to analyze integrated ferromagnetic noise suppressor","2013","IEEE Transactions on Magnetics","49","7","6559308","4032","4035","3","3","10.1109/TMAG.2013.2247031","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84880791485&doi=10.1109%2fTMAG.2013.2247031&partnerID=40&md5=9d02a7dd678db21fa2c7d8835867f391","Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8577, Japan","Muroga S., Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Asazuma Y., Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Yamaguchi M., Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan, New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8577, Japan","This paper describes that the ferromagnetic resonance (FMR) frequency shift can be calculated by an electromagnetic field simulator based on the Maxwell's equation although the relative permeability and the FMR frequency is defined by the Landau-Lifshitz-Gilbert (LLG) and the Kittel's equation. We evaluate the magnetic circuit model with the leakage magnetic flux path for considering the demagnetizing field generated in the magnetic film. As the result, we clarify that the effect of the demagnetizing field is considered as a reluctance of the leakage magnetic flux path in the magnetic circuit calculation, which is considered as the increase of anisotropy field in the Kittel's equation. Furthermore, we show that the simulated FMR frequency by the electromagnetic simulator agrees with the measured values. These results show that the FMR shift in the magnetic film can be calculated and the integrated ferromagnetic noise suppressor can be designed by an electromagnetic field simulator based on the Maxwell's equation. © 2013 IEEE.","Demagnetizing field; electromagnetic noise suppressor; electromagnetic simulator; ferromagnetic films; ferromagnetic resonance frequency; magnetic circuits","Critical currents; Electromagnetic fields; Frequency shift keying; Magnetic circuits; Magnetic devices; Magnetic films; Magnetic flux; Maxwell equations; Simulators; Demagnetizing field; Electromagnetic noise; Electromagnetic simulators; Ferromagnetic films; Ferromagnetic resonance frequency; Ferromagnetic resonance","","","","","","","Rodriguez S., Rusu A., Ismail N.M., WiMAX/LTE receiver front-end in 90 nm CMOS, Proc. IEEE Int. Symp. Circuits Syst. (ISCAS 2009), pp. 1036-1039, (2009); Hwang H., Yoo H., Kim M., Na Y., A design of 700 MHz frequency band LTE receiver front-end with 65 nm CMOS process, Proc. Asia Pacific Microw. Conf. (APMC 2009), pp. 720-723, (2009); Yamaguchi M., Kim K.-H., Kuribara T., Arai K.-I., Thin-film RF noise suppressor integrated in a transmission line, IEEE Transactions on Magnetics, 38, 5, pp. 3183-3185, (2002); Kim K.H., Yamaguchi M., Arai K.-I., Effect of radio-frequency noise suppression on the coplanar transmission line using soft magnetic thin films, J. Appl. Phys., 93, pp. 8002-8004, (2003); Kim K.H., Ohnuma S., Yamaguchi M., RF integrated noise suppressor using soft magnetic films, IEEE Trans. Magn., 40, 4, pp. 3031-3033, (2004); Fukushima T., Koya S., Ono H., Masuda N., Yamaguchi M., Evaluation of RF magnetic thin film noise suppressor integrated onto an operating LSI chip, J. Magn. Soc. Japan, 30, pp. 531-534, (2006); Muroga S., Endo Y., Mitsuzuka Y., Shimda Y., Yamaguchi M., Estimation of peak frequency of loss in noise suppressor using demagnetizing factor, IEEE Trans. Magn., 47, 2, pp. 300-303, (2010); Yamaguchi M., Miyazawa Y., Kaminishi K., Arai K.-I., A new 1 MHz-9 GHz thin-film permeameter using a side-open TEM cell and a planar shielded-loop coil, J. Magn. Soc. Japan, 3, pp. 137-140, (2003); Maehata Y., Tsunashima S., Uchiyama S., Permeability and anisotropy dispersion of amorphous soft magnetic films, J. Magn. Soc. Japan, 13, pp. 307-310, (1989)","S. Muroga; Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; email: muroga@ecei.tohoku.adc.jp","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84880791485" +"Shirzadi A.; Takhtabnoos F.","Shirzadi, Ahmad (55397330800); Takhtabnoos, Fariba (56724189000)","55397330800; 56724189000","A local meshless collocation method for solving Landau-Lifschitz-Gilbert equation","2015","Engineering Analysis with Boundary Elements","61","","","104","113","9","8","10.1016/j.enganabound.2015.07.010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84938884794&doi=10.1016%2fj.enganabound.2015.07.010&partnerID=40&md5=730c7cea7ef405a49f9b9e4f40a01ba2","Department of Mathematics, Persian Gulf University, Bushehr, Iran; Bushehr Mathematics House, Farhang Avenue, Bushehr, Iran","Shirzadi A., Department of Mathematics, Persian Gulf University, Bushehr, Iran, Bushehr Mathematics House, Farhang Avenue, Bushehr, Iran; Takhtabnoos F., Department of Mathematics, Persian Gulf University, Bushehr, Iran","This paper is concerned with a meshless simulation of the two dimensional Landau-Lifschitz-Gilbert (LLG) equation which describes the dynamics of the magnetization inside a ferromagnetic body. After elimination of the time variable by a suitable finite difference scheme, a combination of the meshless local RBF and the finite collocation method is used for spatial discretizations of the field variables. Three test problems are numerically investigated and the results reveal the effectiveness of the method. © 2015 Elsevier Ltd. All rights reserved.","Finite collocation method; Finite differences; Landau-Lifschitz equation; Landau-Lifschitz-Gilbert equation; Local meshless methods; Radial basis functions","Radial basis function networks; Collocation method; Finite differences; Landau-Lifschitz equations; Landau-Lifschitz-Gilbert equation; Mesh-less methods; Radial basis functions; Finite difference method","","","","","","","Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch Comput Methods Eng, 15, 1, pp. 277-309, (2008); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys Z Sowjetunion, 8, pp. 153-169, (1935); Weinan E., Wang X.-P., Numerical methods for the Landau-Lifshitz equation, SIAM J Numer Anal, 38, 5, pp. 1647-1665, (2000); Gilbert T., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys Rev, 100, pp. 1243-1255, (1955); Cimrak I., Existence, regularity and local uniqueness of the solutions to the Maxwell-Landau-Lifshitz system in three dimensions, J Math Anal Appl, 329, 2, pp. 1080-1093, (2007); Alouges F., Kritsikis E., Toussaint J.-C., A convergent finite element approximation for Landau-Lifschitz-Gilbert equation, Physica B, 407, 1, pp. 1345-1349, (2012); Abbasbandy S., Sladek V., Shirzadi A., Sladek J., Numerical simulations for coupled pair of diffusion equations by MLPG method, Comput Model Eng Sci, 71, 1, pp. 15-37, (2011); Dehghan M., Salehi R., The solitary wave solution of the two-dimensional regularized long-wave equation in fluids and plasmas, Comput Phys Commun, 182, 12, pp. 2540-2549, (2011); Dehghan M., Nikpour A., Numerical solution of the system of second-order boundary value problems using the local radial basis functions based differential quadrature collocation method, Appl Math Modell, 37, 18-19, pp. 8578-8599, (2013); Dehghan M., Abbaszadeh M., Mohebbi A., A meshless technique based on the local radial basis functions collocation method for solving parabolic-parabolic Patlak-Keller-Segel chemotaxis model, Eng Anal Bound Elem, 56, pp. 129-144, (2015); Shokri A., Dehghan M., Meshless method using radial basis functions for the numerical solution of two-dimensional complex Ginzburg-Landau equation, Comput Model Eng Sci, 84, 4, pp. 333-358, (2012); Atluri S., Zhu T., A new meshless local Petrov-Galerkin (MLPG) approach in computational mechanics, Comput Mech, 22, pp. 117-127, (1998); Atluri S., Shen S., The meshless local Petrov-Galerkin (MLPG) method: A simple and less-costly alternative to the finite element methods and boundary element methods, Comput Model Eng Sci, 3, pp. 11-51, (2002); Dehghan M., Shirzadi M., Meshless simulation of stochastic advection-diffusion equations based on radial basis functions, Eng Anal Bound Elem, 53, pp. 18-26, (2015); Shirzadi A., Ling L., Convergent overdetermined-RBF-MLPG for solving second order elliptic PDEs, Adv Appl Math Mech, 5, 1, pp. 78-89, (2013); Shirzadi A., Sladek V., Sladek J., A local integral equation formulation to solve coupled nonlinear reaction-diffusion equations by using moving least square approximation, Eng Anal Bound Elem, 37, 1, pp. 8-14, (2013); Shirzadi A., Ling L., Abbasbandy S., Meshless simulations of the two-dimensional fractional-time convection-diffusion-reaction equations, Eng Anal Bound Elem, 36, pp. 1522-1527, (2012); Shirzadi A., Sladek V., Sladek J., A meshless simulations for 2d nonlinear reaction-diffusion Brusselator system, Comput Model Eng Sci, 95, 4, pp. 259-282, (2013); Shirzadi A., Numerical simulations of 1D inverse heat conduction problems using overdetermined RBF-MLPG method, Commun Numer Anal, 2013, pp. 1-11, (2013); Shirzadi A., Meshless local integral equations formulation for the 2d convection-diffusion equations with a nonlocal boundary condition, Comput Model Eng Sci, 85, 1, pp. 45-63, (2012); Lee C.K., Liu X., Fan S.C., Local multiquadric approximation for solving boundary value problems, Comput Mech, 30, pp. 396-409, (2003); Stevens D., Power H., Meng C., Howard D., Cliffe K., An alternative local collocation strategy for high-convergence meshless PDE solutions, using radial basis functions, J Comput Phys, 254, pp. 52-75, (2013); Stevens D., Power H., Lees M., Morvan H., The use of PDE centres in the local RBF Hermitian method for 3D convective-diffusion problems, J Comput Phys, 228, pp. 4606-4624, (2009); Stevens D., Power H., Morvan H., An order-N complexity meshless algorithm for transport-type PDEs, based on local Hermitian interpolation, Eng Anal Bound Elem, 33, pp. 425-441, (2009); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J Numer Anal, 44, 4, pp. 1405-1419, (2006); Jeong D., Kim J., A Crank-Nicolson scheme for the Landau-Lifshitz equation without damping, J Comput Appl Math, 234, 2, pp. 613-623, (2010)","","","Elsevier Ltd","","","","","","09557997","","EABAE","","English","Eng Anal Boundary Elem","Article","Final","","Scopus","2-s2.0-84938884794" +"Taniguchi T.","Taniguchi, Tomohiro (36180180300)","36180180300","Nonlinear analysis of magnetization dynamics excited by spin Hall effect","2015","Physical Review B - Condensed Matter and Materials Physics","91","10","104406","","","","21","10.1103/PhysRevB.91.104406","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84961288510&doi=10.1103%2fPhysRevB.91.104406&partnerID=40&md5=a28c31633532807327b31351b6c8df3d","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba, Ibaraki, 305-8568, Japan","We investigate the possibility of exciting self-oscillation in a perpendicular ferromagnet by the spin Hall effect on the basis of a nonlinear analysis of the Landau-Lifshitz-Gilbert (LLG) equation. In the self-oscillation state, the energy supplied by the spin torque during a precession on a constant energy curve should equal the dissipation due to damping. Also, the current to balance the spin torque and the damping torque in the self-oscillation state should be larger than the critical current to destabilize the initial state. We find that these conditions in the spin Hall system are not satisfied by deriving analytical solutions of the energy supplied by the spin transfer effect and the dissipation due to the damping from the nonlinear LLG equation. This indicates that the self-oscillation of a perpendicular ferromagnet cannot be excited solely by the spin Hall torque. © 2015 American Physical Society.","","","","","","","Japan Society for the Promotion of Science; Japan Society for the Promotion of Science, JSPS, (25790044)","","Wiggins S., Introduction to Applied Nonlinear Dynamical Systems and Chaos, (2003); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature (London), 425, (2003); Rippard W.H., Pufall M.R., Kaka S., Russek S.E., Silva T.J., Phys. Rev. Lett., 92, (2004); Kubota H., Fukushima A., Ootani Y., Yuasa S., Ando K., Maehara H., Tsunekawa K., Djayaprawira D.D., Watanabe N., Suzuki Y., Jpn. J. Appl. Phys., 44, (2005); Mangin S., Ravelosona D., Katine J.A., Carey M.J., Terris B.D., Fullerton E.E., Nat. Mater., 5, (2006); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Et al., Nat. Mater., 6, (2007); Zeng Z., Amiri P.K., Krivorotov I., Zhao H., Finocchio G., Wang J.-P., Katine J.A., Huai Y., Langer J., Galatsis K., Et al., ACS Nano, 6, (2012); Kubota H., Yakushiji K., Fukushima A., Tamaru S., Konoto M., Nozaki T., Ishibashi S., Saruya T., Yuasa S., Taniguchi T., Et al., Appl. Phys. Express, 6, (2013); Sun J.Z., Phys. Rev. B, 62, (2000); Grollier J., Cros V., Jaffres H., Hamzic A., George J.M., Faini G., Youssef J.B., Legall H., Fert A., Phys. Rev. B, 67, (2003); Bertotti G., Mayergoyz I.D., Serpico C., J. Appl. Phys., 95, (2004); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., D'Aquino M., Bonin R., Phys. Rev. Lett., 94, (2005); Bertotti G., Mayergoyz I.D., Serpico C., J. Appl. Phys., 99, (2006); Apalkov D.M., Visscher P.B., Phys. Rev. B, 72, (2005); Dykman M., Fluctuating Nonlinear Oscillators, (2012); Newhall K.A., Eijnden E.V., J. Appl. Phys., 113, (2013); Taniguchi T., Utsumi Y., Marthaler M., Golubev D.S., Imamura H., Phys. Rev. B, 87, (2013); Taniguchi T., Utsumi Y., Imamura H., Phys. Rev. B, 88, (2013); Taniguchi T., Arai H., Tsunegi S., Tamaru S., Kubota H., Imamura H., Appl. Phys. Express, 6, (2013); Taniguchi T., Appl. Phys. Express, 7, (2014); Pinna D., Kent A.D., Stein D.L., Phys. Rev. B, 88, (2013); Pinna D., Stein D.L., Kent A.D., Phys. Rev. B, 90, (2014); Ando K., Takahashi S., Harii K., Sasage K., Ieda J., Maekawa S., Saitoh E., Phys. Rev. Lett., 101, (2008); Miron I.M., Gaudin G., Auffret S., Rodmacq B., Schuhl A., Pizzini S., Vogel J., Gambardella P., Nat. Mater., 9, (2010); Miron I.M., Garello K., Gaudin G., Zermatten P.-J., Costache M.V., Auffret S., Bandiera S., Rodmacq B., Schuhl A., Gambardella P., Nature (London), 476, (2011); Liu L., Lee O.J., Gudmundsen T.J., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 109, (2012); Liu L., Pai C.-F., Li Y., Tseng H.W., Ralph D.C., Buhrman R.A., Science, 336, (2012); Liu L., Pai C.-F., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 109, (2012); Niimi Y., Kawanishi Y., Wei D.H., Deranlot C., Yang H.X., Chshiev M., Valet T., Fert A., Otani Y., Phys. Rev. Lett., 109, (2012); Haney P.M., Lee H.-W., Lee K.-J., Manchon A., Stiles M.D., Phys. Rev. B, 87, (2013); Haney P.M., Lee H.-W., Lee K.-J., Manchon A., Stiles M.D., Phys. Rev. B, 88, (2013); Kim J., Sinha J., Hayashi M., Yamanouchi M., Fukami S., Suzuki T., Mitani S., Ohno H., Nat. Mater., 12, (2013); Kim J., Sinha J., Mitani S., Hayashi M., Takahashi S., Maekawa S., Yamanouchi M., Ohno H., Phys. Rev. B, 89, (2014); Torrejon J., Kim J., Sinha J., Mitani S., Hayashi M., Yamanouchi M., Ohno H., Nat. Commun., 5, (2014); Tserkovnyak Y., Bender S.A., Phys. Rev. B, 90, (2014); Yu G., Upadhyaya P., Fan Y., Alzate J., Jiang W., Wong K.L., Takei S., Bender S.A., Chang L.-T., Jiang Y., Et al., Nat. Nanotech., 9, (2014); Hayashi M.; Pauyac C.O., Wang X., Chshiev M., Manchon A., Appl. Phys. Lett., 102, (2013); Garello K., Miron I.M., Avci C.O., Freimuth F., Mokrousov Y., Blugel S., Auffret S., Boulle O., Gaudin G., Gambardella P., Nat. Nanotech., 8, (2013); Qiu X., Deorani P., Narayanapillai K., Lee K.-S., Lee K.-J., Lee H.-W., Yang H., Sci. Rep., 4, (2014); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. B, 66, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. B, 67, (2003); Ciccarelli C., Hals K.M.D., Irvine A., Novak V., Tserkovnyak Y., Kurebayashi H., Brataas A., Ferguson A., Nat. Nanotech., 10, (2015); Taniguchi T., Imamura H., Phys. Rev. B, 76, (2007)","","","American Physical Society","","","","","","10980121","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84961288510" +"Wu F.-S.; Horng L.; Kao Y.-M.; Wu J.-C.","Wu, Feng-Sheng (24451581500); Horng, Lance (7003351523); Kao, Yee-Mou (7201671090); Wu, Jong-Ching (57154842800)","24451581500; 7003351523; 7201671090; 57154842800","Micromagnetic modeling on current-induced multiple domain-wall motion in permalloy nanotubes","2014","IEEE Transactions on Magnetics","50","11","6971646","","","","0","10.1109/TMAG.2014.2325022","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84915745502&doi=10.1109%2fTMAG.2014.2325022&partnerID=40&md5=c0304e86c93c9bf68a2e4c737c44e741","Department of Physics, National Changhua University of Education, Changhua, 500, Taiwan","Wu F.-S., Department of Physics, National Changhua University of Education, Changhua, 500, Taiwan; Horng L., Department of Physics, National Changhua University of Education, Changhua, 500, Taiwan; Kao Y.-M., Department of Physics, National Changhua University of Education, Changhua, 500, Taiwan; Wu J.-C., Department of Physics, National Changhua University of Education, Changhua, 500, Taiwan","We performed micromagnetic modeling on moving multiple data bits (2-64 bits) in permalloy (Ni80Fe20) cylindrical nanotubes (PCNTs) and numerically investigated the domain-wall movement, which relies on the applied current, the Gilbert damping factor α and radii ratio β. It was found that current-driven multiple transverse domain walls (TDWs) motion in nanotubes with an outer diameter below 25 nm and β > 0.33) was characteristic of an exceptional massless mobility. We observed that the velocity of TDWs confined in nanotubes, which was in proportion to the applied current, depended mainly on the sizes of the tubes, and α but was independent of the number of TDWs. The obtained results offer a way to design the magnetization structures for the DW-based devices by controlling the nanotube geometric and material parameters. © 2014 IEEE.","Domain-wall motion; Landau-Lifshitz-Gilbert (LLG) equation; magnetic nanotube","Magnetic recording; Nanotubes; Nickel alloys; Yarn; Cylindrical nanotube; Domain wall motion; Gilbert damping; Landau-Lifshitz-Gilbert equations; Magnetic nanotubes; Material parameter; Micromagnetic modeling; Multiple domains; Domain walls","","","","","","","Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, 5873, pp. 190-194, (2008); Tanigawa H., Et al., Domain wall motion induced by electric current in a perpendicularly magnetized Co/Ni nano-wire, Appl. Phys. Exp., 2, 5, (2009); Chiba M., Et al., Control of multiple magnetic domain walls by current in a Co/Ni nano-wire, Appl. Phys. Exp., 3, (2010); Jang Y., Mascaro M.D., Beach G.S.D., Ross C.A., Current-driven domain wall motion in heterostructured ferromagnetic nanowires, Appl. Phys. Lett., 100, (2012); Myers E.B., Ralph D.C., Katine J.A., Louie R.N., Buhrman R.A., Current-induced switching of domains in magnetic multilayer devices, Science, 285, 5429, pp. 867-870, (1999); Grollier J., Et al., Switching a spin valve back and forth by current-induced domain wall motion, Appl. Phys. Lett., 83, 3, (2003); Klaui M., Et al., Domain wall motion induced by spin polarized currents in ferromagnetic ring structures, Appl. Phys. Lett., 83, 1, (2003); Vernier N., Allwood D.A., Atkinson D., Cooke M.D., Cowburn R.P., Domain wall propagation in magnetic nanowires by spin-polarized current injection, Europhys. Lett., 65, 4, (2004); Wang Z.K., Et al., Spin waves in nickel nanorings of large aspect ratio, Phys. Rev. Lett., 94, 13, (2005); Nielsch K., Castano F.J., Ross C.A., Krishnan R., Magnetic properties of template-synthesized cobalt/polymer composite nanotubes, J. Appl. Phys., 98, (2005); Chen A.P., Usov N.A., Blanco J.M., Gonzalez J., Equilibrium magnetization states in magnetic nanotubes and their evolution in external magnetic field, J. Magn. Magn. Mater., 316, 2, pp. e317-e319, (2007); Usov N.A., Zhukov A., Gonzalez J., Domain walls and magnetization reversal process in soft magnetic nanowires and nanotubes, J. Magn. Magn. Mater., 316, 2, pp. 255-261, (2007); Sousa C.T., Et al., Tunning pore filling of anodic alumina templates by accurate control of the bottom barrier layer thickness, Nanotechnology, 22, 31, (2011); Proenca M.P., Sousa C.T., Ventura J., Vazquez M., Araujo J.P., Ni growth inside ordered arrays of alumina nanopores: Enhancing the deposition rate, Electrochim. Acta, 72, pp. 215-221, (2012); Proenca M.P., Sousa C.T., Escrig J., Ventura J., Vazquez M., Araujo J.P., Magnetic interactions and reversal mechanisms in Co nanowire and nanotube arrays, J. Appl. Phys., 113, (2013); Landeros P., Allende S., Escrig J., Salcedo E., Altbir D., Vogel E.E., Reversal modes in magnetic nanotubes, Appl. Phys. Lett., 90, (2007); Yan M., Kakay A., Gliga S., Hertel R., Beating the walker limit with massless domain walls in cylindrical nanowires, Phys. Rev. Lett., 104, (2010); LLG Micromagnetics Simulator [Commercial Codes]; Zhang S., Li Z., Roles of nonequilibrium conduction electrons on the magnetization dynamics of ferromagnets, Phys. Rev. Lett., 93, 12, (2004); Li Z., He J., Zhang S., Effects of spin current on ferromagnets (invited), J. Appl. Phys., 9, (2006); Landeros P., Suarez O.J., Cuchillo A., Vargas P., Equilibrium states and vortex domain wall nucleation in ferromagnetic nanotubes, Phys. Rev. B, 79, 2, (2009); Franchin M., Fischbacher T., Bordignon G., De Groot P., Fangohr H., Landau analysis of the symmetry of the magnetic structure and magnetoelectric interaction in multiferroics, Phys. Rev. B, 8, (2008); Otalora J.A., Lopez-Lopez J.A., Nunez A.S., Landeros P., Domain wall manipulation in magnetic nanotubes induced by electric current pulses, J. Phys., Condens. Matter, 24, 43, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84915745502" +"Nobert J.; Mugo M.; Gadain H.","Nobert, Joel (6505519436); Mugo, Margaret (56185339100); Gadain, Hussein (6505732065)","6505519436; 56185339100; 6505732065","Estimation of design floods in ungauged catchments using a regional index flood method. A case study of Lake Victoria Basin in Kenya","2014","Physics and Chemistry of the Earth","67-69","","","4","11","7","11","10.1016/j.pce.2014.02.001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84901651499&doi=10.1016%2fj.pce.2014.02.001&partnerID=40&md5=da3f04df12f42b32e6b5cf0d2e5c2171","University of Dar es Salaam, TZA, Nairobi, Dar es Salaam, Kenya; Food and Agricultural Organization of the United Nations (FAO), Somalia Water and Land Information Management (SWALIM), Nairobi, Kenya","Nobert J., University of Dar es Salaam, TZA, Nairobi, Dar es Salaam, Kenya; Mugo M., Food and Agricultural Organization of the United Nations (FAO), Somalia Water and Land Information Management (SWALIM), Nairobi, Kenya; Gadain H., Food and Agricultural Organization of the United Nations (FAO), Somalia Water and Land Information Management (SWALIM), Nairobi, Kenya","Reliable estimation of flood magnitudes corresponding to required return periods, vital for structural design purposes, is impacted by lack of hydrological data in the study area of Lake Victoria Basin in Kenya. Use of regional information, derived from data at gauged sites and regionalized for use at any location within a homogenous region, would improve the reliability of the design flood estimation. Therefore, the regional index flood method has been applied. Based on data from 14 gauged sites, a delineation of the basin into two homogenous regions was achieved using elevation variation (90-m DEM), spatial annual rainfall pattern and Principal Component Analysis of seasonal rainfall patterns (from 94 rainfall stations). At site annual maximum series were modelled using the Log normal (LN) (3P), Log Logistic Distribution (LLG), Generalized Extreme Value (GEV) and Log Pearson Type 3 (LP3) distributions. The parameters of the distributions were estimated using the method of probability weighted moments. Goodness of fit tests were applied and the GEV was identified as the most appropriate model for each site. Based on the GEV model, flood quantiles were estimated and regional frequency curves derived from the averaged at site growth curves. Using the least squares regression method, relationships were developed between the index flood, which is defined as the Mean Annual Flood (MAF) and catchment characteristics. The relationships indicated area, mean annual rainfall and altitude were the three significant variables that greatly influence the index flood. Thereafter, estimates of flood magnitudes in ungauged catchments within a homogenous region were estimated from the derived equations for index flood and quantiles from the regional curves. These estimates will improve flood risk estimation and to support water management and engineering decisions and actions. © 2014 Elsevier Ltd.","Flood magnitude; Regionalization","East African Lakes; Kenya; Lake Victoria; Catchments; Lakes; Least squares approximations; Probability distributions; Rain; Regression analysis; Risk perception; Runoff; Structural design; Water management; Catchment characteristics; Design flood estimation; Flood magnitudes; Generalized extreme value; Least-squares regression method; Log-logistic distribution; Probability weighted moments; Regionalization; catchment; design flood; flood control; magnitude; principal component analysis; rainfall; Floods","","","","","Food and Agriculture Organization; WaterNet; University of Dar es Salaam, UDSM","This work was supported through financial support from WaterNet. The authors would also like to acknowledge the support of facilities provided by the Water Resources Engineering Department, University of Dar es Salaam, Tanzania and, the Somalia office of the Food and Agriculture Organization (FAO).","Alexander W.J.R., Flood Hydrology of Southern Africa, (1990); Capesius J.P., Stephens V.C., Regional regression equations for estimation of natural streamflow statistics in Colorado, (2009); Cunderlik J.M., Burn D.H., The use of flood regime information in regional flood frequency analysis, Hydrol. Sci.-J.-des Sci. Hydrol., 47, 1, (2001); Gadain H.M., Development and Application of Decision Support Tools for Lake Victoria Sub-Catchments, PhD Thesis, University of Dar es Salaam, Tanzania., (2013); Hamed K.H., Rao A.R., Flood Frequency Analysis, (2000); Hosking J.R.M., L - Moments"" Analysis and estimation of distribution using linear combination of order statistics, J.R. Stat., Ser B, 52, 1, pp. 105-124, (1990); Hosking J.R.M., Wallis J.R., Regional Frequency Analysis: ""Approach Based on L-Moments"", (1997); Kachroo R.K., Mkhandi S.H., Parida B.P., Flood frequency analysis of southern Africa: ""I. Delineation of homogenous regions, Hydrol. Sci. J., 45, 3, pp. 437-448, (2000); Kjeldsen T.R., Smithers J.C., Schulze R.E., Regional flood frequency analysis in the KwaZulu-Natal province, South Africa, using the index-flood method, J. Hydrol. (Amst), 255, pp. 194-211, (2002); Kumar R., Chatterjee C., Kumar S., Lohani A.K., Singh R.D., Development of Regional Flood Frequency Relationships Using L-moments for Middle Ganga Plains Subzone 1(f) of India, Water Resour. Manage., 17, pp. 243-257, (2003); Mkhandi S., Kachroo S., Regional flood frequency analysis for Southern Africa. In: Southern African FRIEND, Technical Documents in Hydrology No. 15, UNESCO, Paris, France., (1997); Noto L.V., La Loggia G., Use of L-moments approach for regional flood frequency analysis in sicily, Italy, Water Resour Manage, 23, pp. 2207-2229, (2009); Patil S., Stieglitz M., Controls on hydrologic similarity: role of nearby gauged catchments for prediction at an ungauged catchment, Hydrol. Earth Syst. Sci., 16, 551-562, (2012); Semu A., Abebe S., Identification and delineation of hydrological homogeneous regions-the case study of blue Nile river basin, (2004); Sine A., Ayalew S., Identification and Delineation of Hydrological Homogeneous Regions-The case study of Blue Nile River Basin, Proceedings, Lake Abaya Research Symposium, (2004); Wiltshire S.E., Regional flood frequency analysis I: homogeneity statistics, Hydrol. Sci. J., 31, pp. 321-333, (1986); Xu B.X., (1999)","J. Nobert; University of Dar es Salaam, TZA, Nairobi, Dar es Salaam, Kenya; email: njoelk@yahoo.com","","Elsevier Ltd","","","","","","14747065","","PCEHA","","English","Phys. Chem. Earth","Article","Final","","Scopus","2-s2.0-84901651499" +"Kim J.; Zhao H.; Jiang Y.; Klemm A.; Wang J.-P.; Kim C.H.","Kim, Jongyeon (56252031500); Zhao, Hui (7404778325); Jiang, Yanfeng (17436165500); Klemm, Angeline (37052153300); Wang, Jian-Ping (35782368600); Kim, Chris H. (8325011400)","56252031500; 7404778325; 17436165500; 37052153300; 35782368600; 8325011400","Scaling analysis of in-plane and perpendicular anisotropy magnetic tunnel junctions using a physics-based model","2014","Device Research Conference - Conference Digest, DRC","","","6872344","155","156","1","12","10.1109/DRC.2014.6872344","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84906567089&doi=10.1109%2fDRC.2014.6872344&partnerID=40&md5=1837a2ae091477948ed08ba1c78bcef7","Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States","Kim J., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States; Zhao H., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States; Jiang Y., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States; Klemm A., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States; Wang J.-P., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States; Kim C.H., Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, United States","Spin transfer torque magnetoresistive random access memory (STT-MRAM) technology has been gaining interest as an alternative to SRAM as it possesses unique properties such as nonvolatility, higher density, and good scalability. Magnetic tunnel junctions (MTJs) based on shape anisotropy, interface anisotropy and crystal anisotropy have been demonstrated with the common goal of reducing the switching current while maintaining sufficient nonvolatility. However, the research community has yet to reach a strong consensus on which MTJ technology will prevail in deeply scaled technology nodes such as 8nm. To answer this open ended question, this paper presents a comprehensive study on the scalability of STT-MRAM based on various MTJ technologies: namely, in-plane MTJ (IMTJ), crystal perpendicular MTJ (c-PMTJ), and interface perpendicular MTJ (i-PMTJ). For a practical analysis, our simulation model captures key physics of STT switching in various MTJs by incorporating dimension-dependent effective anisotropy field (HKeff) into the Landau-Lifshitz-Gilbert (LLG) equation and considering realistic material parameters. © 2014 IEEE.","","Anisotropy; Computer simulation; Scalability; Interface anisotropy; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Open-ended questions; Perpendicular anisotropy; Physics-based modeling; Research communities; Spin transfer torque; Magnetic devices","","","","","","","Zhao H., Et al., JAP, (2011); Chun K.C., Et al., JSSC, pp. 2240-2243, (2013); Apalkov D., Et al., IEEE Trans. Magn., pp. 2240-2243, (2010); Mizukami S., Et al., APL, (2011); Ikeda S., Et al., Nature Mater., pp. 721-724, (2011); Liu X., Et al., JAP, (2011); Takemura R., JSSC, pp. 869-879, (2010)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Electron Devices Society","72nd Device Research Conference, DRC 2014","22 June 2014 through 25 June 2014","Santa Barbara, CA","107082","15483770","978-147995405-6","","","English","Dev. Res. Conf. Conf. Dig.","Conference paper","Final","","Scopus","2-s2.0-84906567089" +"Chen P.; Liu M.; Wang L.; Poo Y.; Wu R.-X.","Chen, Ping (57015808600); Liu, Min (57201860087); Wang, Ling (59088681700); Poo, Yin (35975228700); Wu, Rui-Xin (35363121200)","57015808600; 57201860087; 59088681700; 35975228700; 35363121200","Frequency dispersive complex permittivity and permeability of ferromagnetic metallic granular composite at microwave frequencies","2011","Journal of Magnetism and Magnetic Materials","323","23","","3081","3086","5","21","10.1016/j.jmmm.2011.06.061","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80051601149&doi=10.1016%2fj.jmmm.2011.06.061&partnerID=40&md5=a66069bf45938effcc13d027d1c0b964","School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China","Chen P., School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China; Liu M., School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China; Wang L., School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China; Poo Y., School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China; Wu R.-X., School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China","We experimentally studied the frequency dependent complex permittivity ε and permeability μ of composite composed of carbonyl iron powder (CIP) and epoxy resin in the frequency range 118 GHz. We found that the intrinsic ε and μ of CIP extracted from the measured ε and μ of composites follow the classical Maxwell equations and the LandauLifshitzGilbert (LLG) equation, respectively. The dependences of ε and μ of composites on the volume fraction of CIP (vfCIP) were investigated using the two-exponent phenomenological percolation equation (TEPPE). We found that the TEPPE can fit the experimental results very well. Comparing the results of percolation parameters derived by experimental data at different frequencies, we show that the TEPPE is frequency independent for the composites at microwave frequencies. The results also show that the ε and μ spectrums of composites with definite vfCIP can be correctly calculated by combining the TEPPE with the theoretical models of intrinsic ε and μ. © 2011 Elsevier B.V. All rights reserved.","Complex permittivity and permeability; Ferromagnetic metallic granular composite; Frequency dispersion; Microwave frequency","Ferromagnetic materials; Ferromagnetism; Iron powder; Maxwell equations; Microwave frequencies; Permittivity; Solvents; Carbonyl iron powder; Complex permittivity; Complex permittivity and permeability; Different frequency; Experimental data; Ferromagnetic metallic; Frequency dependent; Frequency dispersion; Frequency independent; Frequency ranges; Granular composites; Theoretical models; Epoxy resins","","","","","National Natural Science Foundation of China, NSFC, (61001017, 61071007); National Natural Science Foundation of China, NSFC; Specialized Research Fund for the Doctoral Program of Higher Education of China, SRFDP, (20100091120045); Specialized Research Fund for the Doctoral Program of Higher Education of China, SRFDP","The authors are grateful to Dr. M. Yang of Nanjing University for his contribution to the VSM measurement. This work was supported by National Natural Science Foundation of China (nos. 61001017 and 61071007 ) and Specialized Research Fund for the Doctoral Program of Higher Education (no. 20100091120045 ). ","Liu L.D., Microwave absorption properties of one thin sheet employing carbonyl iron powder and chlorinated polyethylene, J. Magn. Magn. Mater., 322, pp. 1736-1740, (2010); Chen P., Complex permittivity and permeability of metallic magnetic granular composites at microwave frequencies, J. Phys. D: Appl. Phys., 38, (2005); Bregar V.B., Advantages of ferromagnetic nanoparticle composites in microwave absorbers, IEEE Trans. Magn, 40, pp. 1679-1684, (2004); Chui S.T., Hu L.B., Theoretical investigation on the possibility of preparing left-handed materials in metallic magnetic granular composites, Phys. Rev. B, 65, (2002); Lagarkov A.N., Rozanov K.N., High-frequency behavior of magnetic composites, J. Magn. Magn. Mater., 321, pp. 2082-2092, (2009); Acher O., Modern microwave magnetic materials: Recent advances and trends, J. Magn. Magn. Mater., 321, pp. 2033-2034, (2009); Wu L.Z., High frequency complex permeability of iron particles in a nonmagnetic matrix, J. Appl. Phys., 99, (2006); Rozanov K.N., The effect of shape distribution of inclusions on the frequency dependence of permeability in composites, J. Magn. Magn. Mater., 321, pp. 738-741, (2009); Wu L.Z., Particle size influence to the microwave properties of iron based magnetic particulate composites, J. Magn. Magn. Mater., 285, pp. 233-239, (2005); Brosseau C., Talbot P., Effective magnetic permeability of Ni and Co micro- and nanoparticles embedded in a ZnO matrix, J. Appl. Phys., 97, (2005); Mercier D., Magnetic resonance in spherical CoNi and FeCoNi particles, Phys. Rev. B, 62, pp. 532-544, (2000); Rozanov K.N., Microwave permeability of Co2Z composites, J. Appl. Phys., 97, (2005); Nicolson A.M., Ross G.F., Measurement of the intrinsic properties of materials by time domain techniques, IEEE Trans. Instrum. Meas., 19, pp. 377-382, (1968); Weir W.B., Automatic measurement of complex dielectric constant and permeability at microwave frequency, Proc. IEEE, 62, (1974); Nan C.W., Physics of inhomogeneous inorganic materials, Prog. Mater. Sci., 37, pp. 1-116, (1993); Brosseau C., Modelling and simulation of dielectric heterostructures: A physical survey from a historical perspective, J. Phys. D: Appl Phys., 39, (2006); Merrill W.M., Diaz R.E., Lore M.M., Effective medium theories for artificial materials composed of multiple sizes of spherical inclusions in a host continuum, IEEE Trans. Antenn. Propag., 47, pp. 142-148, (1999); McLachlan D.S., Equations for the conductivity of macroscopic mixtures, J. Phys. C: Solid State Phys, 19, (1986); Deprez N., McLachlan D.S., Sigalas I., Measurement and comparative analysis of the electrical and thermal conductivities, permeability and young's modulus of sintered nickel, Solid State Communications, 66, 8, pp. 869-872, (1988); McLachlan D.S., Electrical resistivity of composites, J. Am. Cream. Soc., 73, (1990); Youngs I.J., Exploring the universal nature of electrical percolation exponents by genetic algorithm fitting with general effective medium theory, J. Phys. D: Appl. Phys, 35, pp. 3127-3137, (2002); Brosseau C., Generalized effective medium theory and dielectric relaxation in particle-filled polymeric resins, Journal of Applied Physics, 91, 5, (2002); Kong J.A., Electromagnetic Wave Theory, (2005); Harrington R.F., Time-harmonic Electromagnetic Fields, (1961); McLachlan D.S., Equation for the conductivity of binary mixtures with anisotropic grain structures, Journal of physics. C. Solid state physics, 20, 7, pp. 865-877, (1987); Feng S., Halperin B., Sen P.N., Transport properties of continuum systems near the percolation threshold, Phys. Rev. B, 35, (1987); Shao W.Z., Conductivity critical exponents lower than the universal value in continuum percolation systems, J. Phys.: Condens. Matter, 20, (2008); Mahan G.D., Long wavelength approach to cermet, Phys. Rev. B, 38, pp. 9500-9502, (1988); Rousselle D., Effective medium at finite frequency: Theory and experiment, J. Appl. Phys., 74, (1993); Liao S.B., Ferromagnetic Physics (3), (2000)","P. Chen; School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China; email: chenping@nju.edu.cn","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-80051601149" +"Drsouza N.; Atulasimha J.; Bandyopadhyay S.","Drsouza, Noel (55355709700); Atulasimha, Jayasimha (6508238509); Bandyopadhyay, Supriyo (57203099871)","55355709700; 6508238509; 57203099871","An ultrafast image recovery and recognition system implemented with nanomagnets possessing biaxial magnetocrystalline anisotropy","2012","IEEE Transactions on Nanotechnology","11","5","6218197","896","901","5","16","10.1109/TNANO.2012.2204769","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84866090291&doi=10.1109%2fTNANO.2012.2204769&partnerID=40&md5=204e3fb717a02127d230a678e7c455b6","Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","Drsouza N., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Atulasimha J., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Bandyopadhyay S., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","A circular magnetic disk with biaxial magnetocrystalline anisotropy has four stable magnetization states which can be used to encode a pixels shade in a black/gray/white image. By solving the Landau-Lifshitz-Gilbert equation, we show that if moderate noise deflects the magnetization slightly from a stable state, it always returns to the original state, thereby automatically denoising the corrupted image. The same system can compare a noisy input image with a stored image and make a matching decision using magnetic tunnel junctions. These tasks are executed at ultrahigh speeds (∼ 2ns for a 512 × 512 pixel image). © 2002-2012 IEEE.","Biaxial magnetocrystalline anisotropy; image processing; Landau-Lifshitz-Gilbert (LLG); nanomagnet","Image processing; Magnetization; Magnetocrystalline anisotropy; Nanomagnetics; Corrupted images; De-noising; Image recovery; Input image; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Magnetic disk; Magnetic tunnel junction; Nanomagnets; Pixel images; Recognition systems; Stable state; Ultra high speed; Ultra-fast; Pixels","","","","","National Science Foundation, NSF, (ECCS-1124714); Semiconductor Research Corporation, SRC, (NRI task 2203.001); Directorate for Engineering, ENG, (1124714); Virginia Commonwealth University, VCU","Manuscript received April 17, 2012; accepted June 3, 2012. Date of publication June 14, 2012; date of current version September 1, 2012. This work was supported in part by the National Science Foundation under the NEB2020 Grant ECCS-1124714, in part by the Semiconductor Research Corporation under NRI task 2203.001, and in part by the Virginia Commonwealth University under the PRIP Grant. The review of this paper was arranged by Associate Editor C. A. Moritz.","Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using multiferroic single domain nanomagnets, Appl. Phys. Lett., 97, pp. 1731051-1731053, (2010); D'souza N., Atulasimha J., Bandyopadhyay S., Four-state nanomagnetic logic using multiferroics, J. Phys. D, Appl. Phys., 44, pp. 2650011-2650017, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Hybrid spintronics and straintronics: A magnetic technology for ultra low energy computing and signal processing, Appl. Phys. Lett., 99, pp. 0631081-0631083, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Energy Dissipation and Switching Delay in Stress-induced Switching of Multiferroic Devices in the Presence of Thermal Fluctuations; Fashami M.S., Atulasimha J., Bandyopadhyay S., Magnetization dynamics, Bennett clocking and associated energy dissipation inmultiferroic logic, Nanotechnology, 22, pp. 1552011-15520110, (2011); Fashami M.S., Atulasimha J., Bandyopadhyay S., Magnetization dynamics, throughput and energy dissipation in a universal multiferroic nanomagnetic logic gate with fan-in and fan-out, Nanotechnology, 23, 2012, pp. 1052011-10520110; Tiercelin N., Dusch Y., Klimov A., Giordano S., Preobrazhensky V., Pernod P., Room temperature magnetoelectric memory cell using stressmediated magnetoelastic switching in nanostructured multilayers, Appl. Phys. Lett., 99, pp. 1925071-1925073, (2011); Pertsev N.A., Kohlstedt H., Resistive switching via the converse magnetoelectric effect in ferromagnetic multilayers on ferroelectric substrates, Nanotechnology, 21, pp. 4752021-4752027, (2010); Cowburn R.P., Welland M.E., Room temperature magnetic quantum cellular automata, Science, 287, 5457, pp. 1466-1468, (2000); Csaba G., Imre A., Bernstein G.H., Porod W., Metlushko V., Nanocomputing by field coupled nanomagnets, IEEE Trans. Nanotechnol., 1, 4, pp. 209-213, (2002); Behin-Aein B., Salahuddin S., Datta S., Switching energy of ferromagnetic logic bits, IEEE Trans.Nanotechnol., 8, 4, pp. 505-514, (2009); Carlton D., Emley N., Tuchfeld E., Bokor J., Simulation studies of nanomagnet-based logic architecture, Nano Lett., 8, 12, pp. 4173-4178, (2008); Srinivasan S., Sarkar A., Behin-Aein B., Datta S., All-spin logic device with inbuilt nonreciprocity, IEEE Trans. Magn., 47, 10, pp. 4026-4032, (2011); D'souza N., Atulasimha J., Bandyopadhyay S., Energy-efficient Bennett clocking scheme for four-state multiferroic logic, IEEE Trans. Nanotechnol., 11, 2, pp. 418-425, (2012); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Single-domain circular nanomagnets, Physical Review Letters, 83, 5, pp. 1042-1045, (1999); Cullity B.D., Graham C.D., Introduction to Magnetic Materials, (2009); Naik R., Kota C., Payson J., Dunifer G., Ferromagnetic-resonance studies of epitaxial Ni, Co, and Fe films grown on Cu(100)/Si(100), Phys. Rev. B, 48, 2, pp. 1008-1013, (1993); Kawai N., Kawahito S., Noise analysis of high-gain, low-noise column readout circuits for CMOS image sensors, IEEE Trans. Electr. Devices, 51, 2, pp. 185-194, (2004); Walowski J., Kaufmann M.D., Lenk B., Hamann C., McCord J., Munzenberg M., Intrinsic and non-local Gilbert damping in polycrystalline nickel studied by Ti:sapphire laser fs spectroscopy, J. Phys. D, Appl. Phys., 41, 16, pp. 1640161-16401610, (2008); Emley N.C., Albert F.J., Ryan E.M., Krivorotov I.N., Ralph D.C., Buhrman R.A., Daughton J.M., Jander A., Reduction of spin transfer by synthetic antiferromagnets, Appl. Phys. Lett., 84, 21, pp. 4257-4259, (2004)","N. Drsouza; Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; email: dsouzanm@vcu.edu","","","","","","","","1536125X","","","","English","IEEE Trans. Nanotechnol.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84866090291" +"Wang D.; Weerasinghe J.; Bellaiche L.","Wang, Dawei (24462862000); Weerasinghe, Jeevaka (36931924200); Bellaiche, L. (7006534936)","24462862000; 36931924200; 7006534936","Atomistic molecular dynamic simulations of multiferroics","2012","Physical Review Letters","109","6","067203","","","","56","10.1103/PhysRevLett.109.067203","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84864867783&doi=10.1103%2fPhysRevLett.109.067203&partnerID=40&md5=f08372ff987dca0e9d1a42e90c9b6f55","Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Xi'An Jiaotong University, Xi'an 710049, China; Physics Department, University of Arkansas, Fayetteville, AR 72701, United States; Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701, United States","Wang D., Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Xi'An Jiaotong University, Xi'an 710049, China, Physics Department, University of Arkansas, Fayetteville, AR 72701, United States; Weerasinghe J., Physics Department, University of Arkansas, Fayetteville, AR 72701, United States; Bellaiche L., Physics Department, University of Arkansas, Fayetteville, AR 72701, United States, Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701, United States","A first-principles-based approach is developed to simulate dynamical properties, including complex permittivity and permeability in the GHz-THz range, of multiferroics at finite temperatures. It includes both structural degrees of freedom and magnetic moments as dynamic variables in Newtonian and Landau-Lifshitz-Gilbert (LLG) equations within molecular dynamics, respectively, with the couplings between these variables being incorporated. The use of a damping coefficient and of the fluctuation field in the LLG equations is required to obtain equilibrated magnetic properties at any temperature. No electromagnon is found in the spin-canted structure of BiFeO 3. On the other hand, two magnons with very different frequencies are predicted via the use of this method. The smallest-in-frequency magnon corresponds to oscillations of the weak ferromagnetic vector in the basal plane being perpendicular to the polarization while the second magnon corresponds to magnetic dipoles going in and out of this basal plane. The large value of the frequency of this second magnon is caused by static couplings between magnetic dipoles with electric dipoles and oxygen octahedra tiltings. © 2012 American Physical Society.","","Computer simulation; Magnetic moments; Magnetic properties; Molecular dynamics; Atomistic molecular dynamics; Basal planes; Complex permittivity; Damping coefficients; Different frequency; Dynamic variables; Dynamical properties; Electric dipole; Finite temperatures; Fluctuation fields; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic dipole; Multiferroics; Newtonians; Oxygen octahedra; Spin-canted structure; Static couplings; Two-magnons; Magnetic couplings","","","","","National Science Foundation, NSF, (1066158, 0001408, 0918970)","","Choi T., Lee S., Choi Y.J., Kiryukhin V., Cheong S.-W., Science, 324, (2009); Yang S.Y., Seidel J., Byrnes S.J., Shafer P., Yang C.-H., Rossell M.D., Yu P., Chu Y.-H., Scott J.F., Ager J.W., Martin L.W., Ramesh R., Nature Nanotech., 5, (2010); Hill N., J. Phys. Chem. B, 104, (2000); Zhao T., Scholl A., Zavaliche F., Lee K., Barry M., Doran A., Cruz M.P., Chu Y.H., Ederer C., Spaldin N.A., Das R.R., Kim D.M., Baek S.H., Eom C.B., Ramesh R., Electrical control of antiferromagnetic domains in multiferroic BiFeO 3 films at room temperature, Nature Materials, 5, 10, pp. 823-829, (2006); Lebeugle D., Colson D., Forget A., Viret M., Bataille A.M., Gukasov A., Phys. Rev. Lett., 100, (2008); Lee S., Choi T., Ratcliff W., Erwin R., Cheong S.-W., Kiryukhin V., Phys. Rev. B, 78, (2008); Lisenkov S., Rahmedov D., Bellaiche L., Phys. Rev. Lett., 103, (2009); Bea H., Et al., Phys. Rev. Lett., 102, (2009); Hatt A.J., Spaldin N.A., Ederer C., Phys. Rev. B, 81, (2010); Zeches R.J., Et al., Science, 326, (2009); Dupe B., Infante I.C., Geneste G., Janolin P.-E., Bibes M., Barthelemy A., Lisenkov S., Bellaiche L., Ravy S., Dkhil B., Phys. Rev. B, 81, (2010); Wojdel J.C., Iniguez J., Phys. Rev. Lett., 105, (2010); Prosandeev S., Kornev I.A., Bellaiche L., Phys. Rev. B, 83, (2011); Prosandeev S., Lisenkov S., Bellaiche L., Phys. Rev. Lett., 105, (2010); Nelson C., Winchester B., Zhang Y., Kim S., Nano Lett., 11, (2011); Antropov V., Tretyakov S., Harmon B., J. Appl. Phys., 81, (1997); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Komandin G.A., Torgashev V.I., Volkov A.A., Porodinkov O.E., Spektor I.E., Bush A.A., Phys. Solid State, 52, (2010); Kamba S., Nuzhnyy D., Savinov M., Sebek J., Petzelt J., Prokleska J., Haumont R., Kreisel J., Phys. Rev. B, 75, (2007); Cazayous M., Gallais Y., Sacuto A., De Sousa R., Lebeugle D., Colson D., Phys. Rev. Lett., 101, (2008); Sushkov A.B., Mostovoy M., Valdes Aguilar R., Cheong S.-W., Drew H.D., J. Phys. Condens. Matter, 20, (2008); Valdes Aguilar R., Mostovoy M., Sushkov A., Zhang C., Choi Y., Cheong S.-W., Drew H., Phys. Rev. Lett., 102, (2009); Kornev I.A., Lisenkov S., Haumont R., Dkhil B., Bellaiche L., Finite-temperature properties of multiferroic BiFeO3, Physical Review Letters, 99, 22, (2007); Albrecht D., Lisenkov S., Ren W., Rahmedov D., Kornev I.A., Bellaiche L., Phys. Rev. B, 81, (2010); Zhong W., Vanderbilt D., Rabe K.M., Phys. Rev. Lett., 73, (1994); Zhong W., Vanderbilt D., Rabe K.M., Phys. Rev. B, 52, (1995); Neaton J.B., Ederer C., Waghmare U.V., Spaldin N.A., Rabe K.M., First-principles study of spontaneous polarization in multiferroic BiFeO 3 , Physical Review B - Condensed Matter and Materials Physics, 71, 1, pp. 0141131-0141138, (2005); Kornev I.A., Bellaiche L., Janolin P.-E., Dkhil B., Suard E., Phase diagram of Pb(Zr,Ti)O3 solid solutions from first principles, Physical Review Letters, 97, 15, (2006); Infante I., Lisenkov S., Dupe B., Bibes M., Fusil S., Jacquet E., Geneste G., Petit S., Courtial A., Juraszek J., Bellaiche L., Barthele my A., Dkhil B., Phys. Rev. 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B, 78, (2008); Ma P.-W., Dudarev S.L., Semenov A.A., Woo C.H., Phys. Rev. e, 82, (2010); Brown W., Phys. Rev., 130, (1963); Kubo R., Hashitsume N., Prog. Theor. Phys. Suppl., 46, (1970); Mentink J.H., Tretyakov M.V., Fasolino A., Katsnelson M.I., Rasing T., J. Phys. Condens. Matter, 22, (2010); Weinan E., Wang X.-P., SIAM J. Numer. Anal., 38, (2000); Arponen T., Leimkuhler B., An efficient geometric integrator for thermostatted anti-/ferromagnetic models, BIT Numerical Mathematics, 44, 3, pp. 403-424, (2004); Daquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, Journal of Computational Physics, 209, 2, pp. 730-753, (2005); Cimrak I., Arch. Comput. Methods Eng., 15, (2008); Skubic B., Hellsvik J., Nordstrom L., Eriksson O., J. Phys. Condens. Matter, 20, (2008); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Caillol J., Levesque D., Weis J., J. Chem. Phys., 85, (1986); Hlinka J., Ostapchuk T., Nuzhnyy D., Petzelt J., Kuzel P., Kadlec C., Vanek P., Ponomareva I., Bellaiche L., Phys. Rev. Lett., 101, (2008); Hermet P., Goffinet M., Kreisel J., Ghosez P., Phys. Rev. B, 75, (2007); Tutuncu H.M., Srivastava G.P., Electronic structure and zone-center phonon modes in multiferroic bulk BiFeO3, Journal of Applied Physics, 103, 8, (2008); Apostolova I., Apostolov A.T., Wesselinowa J.M., J. Phys. Condens. Matter, 21, (2009); Haumont R., Kreisel J., Bouvier P., Hippert F., Phonon anomalies and the ferroelectric phase transition in multiferroic BiFeO3, Physical Review B - Condensed Matter and Materials Physics, 73, 13, pp. 1-4, (2006); Fukumura H., Matsui S., Harima H., Takahashi T., Itoh T., Kisoda K., Tamada M., Noguchi Y., Miyayama M., Observation of phonons in multiferroic BiFeO 3 single crystals by Raman scattering, Journal of Physics Condensed Matter, 19, 36, (2007); Lobo R.P.S.M., Moreira R.L., Lebeugle D., Colson D., Phys. Rev. B, 76, (2007); Rout D., Moon K.-S., Kang S.-J.L., J. Raman Spectrosc., 40, (2009); Lu J., Schmidt M., Lunkenheimer P., Pimenov A., Mukhin A.A., Travkin V.D., Loidl A., J. Phys. Conf. Ser., 200, (2010); Palai R., Schmid H., Scott J.F., Katiyar R.S., Phys. Rev. B, 81, (2010); Porporati A.A., Tsuji K., Valant M., Axelsson A.-K., Pezzotti G., J. Raman Spectrosc., 41, (2010); Hlinka J., Pokorny J., Karimi S., Reaney I.M., Phys. Rev. B, 83, (2011); Weerasinghe J., Wang D., Bellaiche L., Phys. Rev. B, 85, (2012); Pincus P., Phys. Rev. Lett., 5, (1960); De Sousa R., Moore J.E., Appl. Phys. Lett., 92, (2008); Livesey K.L., Stamps R.L., Phys. Rev. B, 81, (2010); Zvezdin A.K., Mukhin A.A., JETP Lett., 89, (2009)","D. Wang; Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education, International Center for Dielectric Research, Xi'An Jiaotong University, Xi'an 710049, China; email: dawei.wang@mail.xjtu.edu.cn","","","","","","","","10797114","","PRLTA","","English","Phys Rev Lett","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-84864867783" +"Muroga S.; Yamaguchi M.","Muroga, Sho (35111642100); Yamaguchi, Masahiro (55541020100)","35111642100; 55541020100","Effect of demagnetizaing field on frequency dispersoin of complex permeability","2014","IEEE International Symposium on Electromagnetic Compatibility","2014-December","","6997283","785","788","3","1","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84942573688&partnerID=40&md5=163946e0da494d1e1eeaf118e71b3d0a","Graduate School of Engineering, Tohoku University, Sendai, Japan","Muroga S., Graduate School of Engineering, Tohoku University, Sendai, Japan; Yamaguchi M., Graduate School of Engineering, Tohoku University, Sendai, Japan","This paper describes that the ferromagnetic resonance (FMR) frequency shift can be calculated by an electromagnetic field simulator based on the Maxwell's equation although the relative permeability and the FMR frequency is defined by the Landau-Lifshitz-Gilbert (LLG) and the Kittel's equation. We evaluate the magnetic circuit model with the leakage magnetic flux path for considering the demagnetizing field generated in the magnetic film. As the result, we clarify that the effect of the demagnetizing field is considered as a reluctance of the leakage magnetic flux path in the magnetic circuit calculation, which is considered as the increase of anisotropy field in the Kittel's equation. Furthermore, we show that the simulated FMR frequency by the electromagnetic simulator agrees with the measured values. © 2014 The Institute of Electronics, Information and Communication Engineer.","demagnetizing field; electromagnetic simulator; ferromagnetic films; ferromagnetic resonance frequency; on-chip electromagnetic noise suppressor","Critical currents; Electromagnetic compatibility; Electromagnetic fields; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic circuits; Magnetic leakage; Maxwell equations; Mechanical permeability; Simulators; Demagnetizing field; Electromagnetic noise; Electromagnetic simulators; Ferromagnetic films; Ferromagnetic resonance frequency; Electromagnetic simulation","","","","","","","Rodriguez S., Rusu A., Ismail N.M., WiMAX/LTE receiver front-end in 90nm CMOS, IEEE International Symposium on Circuits and Systems 2009 (ISCAS 2009), pp. 1036-1039, (2009); Hwang H., Yoo H., Kim M., Na Y., A design of 700 mhz frequency band LTE receiver front-end with 65 nm CMOS process, Asia Pacific Microwave Conference, 2009 (APMC 2009), pp. 720-723, (2009); Yamaguchi M., Kim K.H., Kuribara T., Thin film RF noise suppressor integrated in a transmission line, IEEE Trans. on Magn., pp. 3183-3185, (2002); Kim K.H., Yamaguchi M., Arai K.-I., Effect of radio-frequency noise suppression on the coplanar transmission line using soft magnetic thin films, J. Appl. Phys., 93, pp. 8002-8004, (2003); Kim K.H., Ohnuma S., Yamaguchi M., RF integrated noise suppressor using soft magnetic films, IEEE Trans. Magn., 40, pp. 3031-3033, (2004); Fukushima T., Koya S., Ono H., Masuda N., Yamaguchi M., Evaluation of rf magnetic thin film noise suppressor integrated onto an operating LSI Chip, J. Magn. Soc. Jpn., 30, pp. 531-534, (2006); Muroga S., Endo Y., Mitsuzuka Y., Shimda Y., Yamaguchi M., Estimation of peak frequency of loss in noise suppressor using demagnetizing factor, IEEE Trans. Magn., 47, pp. 300-303, (2010); Yamaguchi M., Miyazawa Y., Kaminishi K., Arai K.-I., A New 1MHz-9GHz thin-film permeameter using a side-open tem cell and a planar shielded-loop coil, J. Magn. Soc. Jpn., 3, pp. 137-140, (2003); Muroga S., Endo Y., Shimada Y., Yamaguchi M., Analysis of magnetic flux through magnetic film with negative permeability, IEEE Transactions on Magnetics, 48, pp. 4320-4323, (2012)","","","Institute of Electrical and Electronics Engineers Inc.","The Institute of Electronics, Information and Communication Engineers, Communications Society (IEICE-CS)","2014 International Symposium on Electromagnetic CompatibiIity, EMC 2014","12 May 2014 through 16 May 2014","Tokyo","114311","10774076","978-488552287-1","IISPD","","English","IEEE Int. Symp. Electromagn. Compat.","Conference paper","Final","","Scopus","2-s2.0-84942573688" +"Kritsikis E.; Vaysset A.; Buda-Prejbeanu L.D.; Alouges F.; Toussaint J.-C.","Kritsikis, E. (25223195800); Vaysset, A. (36728470800); Buda-Prejbeanu, L.D. (11140986400); Alouges, F. (6603626324); Toussaint, J.-C. (35502756000)","25223195800; 36728470800; 11140986400; 6603626324; 35502756000","Beyond first-order finite element schemes in micromagnetics","2014","Journal of Computational Physics","256","","","357","366","9","18","10.1016/j.jcp.2013.08.035","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84884548961&doi=10.1016%2fj.jcp.2013.08.035&partnerID=40&md5=0f47b3ad1936413cef1fe3b9fc6bab63","Laboratoire d'analyse, Géométrie et applications, CNRS UMR 7539, 93430 Villetaneuse, université Paris 13, France; Institut Néel, CNRS and université Joseph Fourier, F-38042 Grenoble, France; SPINTEC, INAC, UMR CEA/CNRS/UJF-Grenoble 1/Grenoble-INP, F-38054 Grenoble, France; CMAP, CNRS and École polytechnique, F-91128 Palaiseau, France","Kritsikis E., Laboratoire d'analyse, Géométrie et applications, CNRS UMR 7539, 93430 Villetaneuse, université Paris 13, France; Vaysset A., SPINTEC, INAC, UMR CEA/CNRS/UJF-Grenoble 1/Grenoble-INP, F-38054 Grenoble, France; Buda-Prejbeanu L.D., SPINTEC, INAC, UMR CEA/CNRS/UJF-Grenoble 1/Grenoble-INP, F-38054 Grenoble, France; Alouges F., CMAP, CNRS and École polytechnique, F-91128 Palaiseau, France; Toussaint J.-C., Institut Néel, CNRS and université Joseph Fourier, F-38042 Grenoble, France","Magnetization dynamics in ferromagnetic materials is ruled by the Landau-Lifshitz-Gilbert equation (LLG). Reliable schemes must conserve the magnetization norm, which is a nonconvex constraint, and be energy-decreasing unless there is pumping. Some of the authors previously devised a convergent finite element scheme that, by choice of an appropriate test space - the tangent plane to the magnetization - reduces to a linear problem at each time step. The scheme was however first-order in time. We claim it is not an intrinsic limitation, and the same approach can lead to efficient micromagnetic simulation. We show how the scheme order can be increased, and the nonlocal (magnetostatic) interactions be tackled in logarithmic time, by the fast multipole method or the non-uniform fast Fourier transform. Our implementation is called feeLLGood. A test-case of the National Institute of Standards and Technology is presented, then another one relevant to spin-transfer effects (the spin-torque oscillator). © 2013 Elsevier Inc.","Finite elements; Landau-Lifshitz equation; Magnetization dynamics; Magnetostatic field; Micromagnetism; Non-uniform fast Fourier transform; Spin-torque oscillator; Spintronics","Fast Fourier transforms; Ferromagnetic materials; Ferromagnetism; Finite element method; Magnetostatics; Spin dynamics; Finite element; Finite-element schemes; First order; Landau Lifshitz equation; Magnetization dynamics; Magnetostatic field; Micromagnetics; Micromagnetisms; Non-uniform fast Fourier transforms; Spin-torque oscillators; Magnetization","","","","","Agence Nationale de la Recherche, ANR, (BLAN08-3_353929); Agence Nationale de la Recherche, ANR","This research was supported in part by ANR blanche Micro-MANIP ( BLAN08-3_353929 ).","Brown W., Micromagnetics, (1963); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1-2, (1996); Visintin A., On Landau-Lifshitz equation for ferromagnetism, Jpn. J. Appl. Math., 2, pp. 69-84, (1985); Alouges F., Soyeur A., On global weak solutions for Landau Lifchitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, 11, pp. 1071-1084, (1992); Braess D., Finite Elements, (2001); Firastrau I., Gusakova D., Houssameddine D., Ebels U., Cyrille M.-C., Delaet B., Dieny B., Redon O., Toussaint J.-C., Buda-Prejbeanu L.D., Modeling of the perpendicular polarizer-planar free layer spin torque oscillator: Micromagnetic simulations, Phys. Rev. B, 78, (2008); Scholz W., Fidler J., Schrefl T., Suess D., Dittrich R., Forster H., Tsiantos V., Scalable parallel micromagnetic solvers for magnetic nanostructures, Comput. Mater. Sci., 28, pp. 366-383, (2003); Alouges F., A new finite element scheme for Landau-Lifchitz equations, Discrete Contin. Dyn. Syst., Ser. S, 1, 2, pp. 187-196, (2008); Alouges F., Kritsikis E., Toussaint J.-C., A convergent finite-element approximation for the Landau-Lifshitz-Gilbert equation, Physica B, 407, pp. 1345-1349, (2012); Alouges F., A new algorithm for computing liquid crystal stable configurations: The harmonic mapping case, SIAM J. Numer. Anal., 34, 5, pp. 1708-1726, (1997); Alouges F., Jaisson P., Convergence of a finite elements discretization for the Landau Lifshitz equations, Math. Models Methods Appl. Sci., 16, pp. 299-313, (2006); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, 1, pp. 220-238, (2005); Goldenits P., Praetorius D., Suess D., Convergent geometric integrator for the Landau-Lifshitz-Gilbert equation in micromagnetics, Proc. Appl. Math. Mech., 11, pp. 775-776, (2011); Potts D., Steidl G., Tasche M., Fast Fourier transforms for nonequispaced data: A tutorial, Modern Sampling Theory: Mathematics and Applications, pp. 247-270, (2001); Kritsikis E., Toussaint J.-C., Fruchart O., Szambolics H., Buda-Prejbeanu L.D., Fast computation of magnetostatic fields by non-uniform fast Fourier transforms, Appl. Phys. Lett., 93, 13, (2008); Greengard L., Rokhlin V., A fast algorithm for particle simulations, J. Comput. Phys., 135, 2, pp. 280-292, (1997); Greengard L., The Rapid Evaluation of Potential Fields in Particle Systems, (1987); Keiner J., Kunis S., Potts D., (2008); Ying L., Biros G., Zorin D., A kernel-independent adaptive Fast Multipole Method in two and three dimensions, J. Comput. Phys., 196, 2, pp. 591-626, (2004); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, Phys. Rev. Lett., 84, pp. 3149-3152, (2000); Myers E.B., Ralph D.C., Katine J.A., Louie R.N., Buhrman R.A., Current-induced switching of domains in magnetic multilayer devices, Science, 285, 5429, pp. 867-870, (1999); Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, 5873, pp. 190-194, (2008); Kiselev S., Sankey J., Krivorotov I., Emley N., Schoelkopf R., Buhrman R., Ralph D., Microwave oscillations of a nanomagnet driven by a spin-polarized current, Nature, 425, 6956, pp. 380-383, (2003)","E. Kritsikis; Laboratoire d'analyse, Géométrie et applications, CNRS UMR 7539, 93430 Villetaneuse, université Paris 13, France; email: kritsikis@math.univ-paris13.fr","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","","Scopus","2-s2.0-84884548961" +"Noh S.J.; Miyamoto Y.; Okuda M.; Hayashi N.; Kim Y.K.","Noh, Su Jung (16310885800); Miyamoto, Yasuyoshi (57192931792); Okuda, Mitsunobu (52364707700); Hayashi, Naoto (36194961300); Kim, Young Keun (24502952300)","16310885800; 57192931792; 52364707700; 36194961300; 24502952300","Control of magnetic domains in Co/Pd multilayered nanowires with perpendicular magnetic anisotropy","2012","Journal of Nanoscience and Nanotechnology","12","1","","428","432","4","12","10.1166/jnn.2012.5404","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861167906&doi=10.1166%2fjnn.2012.5404&partnerID=40&md5=6ea14bb6b3c7a7e7aae78c9941ebc59e","Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea; NHK Science and Technology Research Laboratories, Tokyo 157-8510, Japan","Noh S.J., Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea; Miyamoto Y., NHK Science and Technology Research Laboratories, Tokyo 157-8510, Japan; Okuda M., NHK Science and Technology Research Laboratories, Tokyo 157-8510, Japan; Hayashi N., NHK Science and Technology Research Laboratories, Tokyo 157-8510, Japan; Kim Y.K., Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, South Korea","Magnetic domain wall (DW) motion induced by spin transfer torque in magnetic nanowires is of emerging technological interest for its possible applications in spintronic memory or logic devices. Co/Pd multilayered magnetic nanowires with perpendicular magnetic anisotropy were fabricated on the surfaces of Si wafers by ion-beam sputtering. The nanowires had different sized widths and pinning sites formed by an anodic oxidation method via scanning probe microscopy (SPM) with an MFM tip. The magnetic domain structure was changed by an anodic oxidation method. To discover the current-induced DW motion in the Co/Pd nanowires, we employed micromagnetic modeling based on the Landau.Lifschitz.Gilbert (LLG) equation. The split DW motions and configurations due to the edge effects of pinning site and nanowire appeared. Copyright © 2012 American Scientific Publishers All rights reserved.","Domain wall; Magnetic nanowire; Perpendicular magnetic anisotropy","Anisotropy; Cobalt; Magnetic Fields; Materials Testing; Nanostructures; Palladium; Particle Size; Anodic oxidation; Domain walls; Logic devices; Magnetic anisotropy; Magnetic domains; Magnetic structure; Scanning probe microscopy; Silicon wafers; cobalt; nanomaterial; palladium; Anodic oxidation method; Edge effect; Ion-beam sputtering; Magnetic nanowires; Micromagnetic modeling; Multi-layered; Perpendicular magnetic anisotropy; Pinning sites; Si wafer; Spin transfer torque; anisotropy; article; chemistry; magnetic field; materials testing; particle size; ultrastructure; Nanowires","","cobalt, 7440-48-4; Cobalt, 7440-48-4; Palladium, 7440-05-3","","","","","Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Thomas L., Hayashi M., Jiang X., Moriya R., Rettner C., Parkin S.S.P., Nature, 443, (2006); Hayashi M., Thomas L., Bazaliy Y.B., Rettner C., Moriya R., Jiang X., Parkin S.S.P., Phys. Rev. Lett., 96, (2006); Beach G.S.D., Knutson C., Nistor C., Tsoi M., Erskine J.L., Phys. Rev. Lett., 97, (2006); Saitoh E., Miyajima H., Yamaoka T., Tatara G., Nature, 432, (2004); Yamanouchi M., Chiba D., Matsukura F., Ohno H., Nature, 428, (2004); Noh S.J., Tan R.P., Chun B.S., Kim Y.K., J. Magn. Magn. Mater., 322, (2010); Thiaville A., Nakatani Y., Miltat J., Suzuki Y., Europhys. Lett., 69, (2005); Li Z., Zhang S., Phys. Rev. Lett., 92, (2004); Thomas L., Hayashi M., Jiang X., Moriya R., Rettner C., Parkin S., Science, 315, (2007); Yamanouchi M., Ieda J., Matsukura F., Barnes S.E., Maekawa S., Ohno H., Science, 317, (2007); Koyama T., Yamada G., Tanigawa H., Kasai S., Ohshima N., Fukami S., Ishiwata N., Nakatani Y., Ono T., Appl. Phys. Express, 1, (2008); Kim S.D., Chun B.S., Kim Y.K., J. Appl. Phys., 101, (2007); Massoud H.Z., Plummer J.D., Irene E.A., J. Electrochem. Soc., 132, (1985); Garcia R., Calleja M., Perez-Murano F., Appl. Phys. Lett., 72, (1998); Tello M., Garcia R., Appl. Phys. Lett., 79, (2001); Sayama J., Kawaji J., Asahi T., Hokkyo J., Osaka T., IEEE Trans. Magn., 39, (2003); Nozaki Y., Narita N., Tanaka T., Matsuyama K., Appl. Phys. Lett., 95, (2009); Qi X.Y., Stadler B.J.H., Victora R.H., Judy J.H., Hellwig O., Supper N., IEEE Trans. Magn., 40, (2004); He P., Shan Z.S., Woollam J.A., Sellmyer D.J., J. Appl. Phys., 73, (1993); Hashimoto S., Ochiai Y., Aso K., Jpn. J. Appl. Phys., 28, (1989); Tatara G., Kohno H., Phys. Rev. Lett., 92, (2004); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Shan R., Gao T.R., Zhou S.M., Wu X.S., Fang Y.K., Han B.S., J. Appl. Phys., 99, (2006); Yang Y.W., Chen Y.B., Wu Y.C., Chen X.Y., Kong M.G., J. Nanomater., 2010, (2010)","","","","","","","","","15334899","","JNNOA","22523997","English","J. Nanosci. Nanotechnol.","Conference paper","Final","","Scopus","2-s2.0-84861167906" +"Bonhomme P.; Manipatruni S.; Iraei R.M.; Rakheja S.; Chang S.-C.; Nikonov D.E.; Young I.A.; Naeemi A.","Bonhomme, Phillip (56089215800); Manipatruni, Sasikanth (15832613300); Iraei, Rouhollah M. (56089245800); Rakheja, Shaloo (36343861400); Chang, Sou-Chi (37085140500); Nikonov, Dmitri E. (7003272404); Young, Ian A. (7402362397); Naeemi, Azad (6602173751)","56089215800; 15832613300; 56089245800; 36343861400; 37085140500; 7003272404; 7402362397; 6602173751","Circuit simulation of magnetization dynamics and spin transport","2014","IEEE Transactions on Electron Devices","61","5","6780619","1553","1560","7","34","10.1109/TED.2014.2305987","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84899936240&doi=10.1109%2fTED.2014.2305987&partnerID=40&md5=8c0ce56d3d3a6f40dcd1441e2895c037","School of Electrical and Computer Engineering, Georgia Institute of Techology, Atlanta, GA 30332, United States; Components Research Group, Intel Corporation, Hillsboro, OR 97124, United States; Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139, United States","Bonhomme P., School of Electrical and Computer Engineering, Georgia Institute of Techology, Atlanta, GA 30332, United States; Manipatruni S., Components Research Group, Intel Corporation, Hillsboro, OR 97124, United States; Iraei R.M., School of Electrical and Computer Engineering, Georgia Institute of Techology, Atlanta, GA 30332, United States; Rakheja S., Microsystems Technology Laboratories, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Chang S.-C., School of Electrical and Computer Engineering, Georgia Institute of Techology, Atlanta, GA 30332, United States; Nikonov D.E., Components Research Group, Intel Corporation, Hillsboro, OR 97124, United States; Young I.A., Components Research Group, Intel Corporation, Hillsboro, OR 97124, United States; Naeemi A., School of Electrical and Computer Engineering, Georgia Institute of Techology, Atlanta, GA 30332, United States","In this paper, compact circuit models for spintronic devices have been developed by manipulating the underlying physical equations. We have simulated, via circuit simulation: 1) the magnetization dynamics governed by the Landau-Lifshitz-Gilbert (LLG) equation and 2) the spin transport physics governed by the spin drift-diffusion equation. The models have been validated using numerical and analytical solutions of the LLG equation and the spin drift-diffusion equations, respectively. Simulations of an all-spin logic device demonstrate the applications of the developed models in device and circuit simulation. © 1963-2012 IEEE.","Circuit theory; magnetoelectronics; modeling; spin polarized transport ¿","Circuit simulation; Circuit theory; Computer simulation; Logic devices; Magnetization; Magnetoelectronics; Models; Physics; Circuit models; Developed model; Driftdiffusion equations; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Physical equations; Spin polarized transport; Spintronic device; Spin dynamics","","","","","","","Srinivasan S., Sarkar A., Behin-Aein B., Datta S., All-spin logic device with inbuilt nonreciprocity, IEEE Trans. Magn., 47, 10, pp. 4026-4032, (2011); Zutic I., Fabian J., Das Sarma S., Spintronics: Fundamentals and applications, Rev. Mod. Phys., 76, pp. 323-410, (2004); Slonczewski J., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater, 159, 1-2, (1996); Behin-Aein B., Datta D., Salahuddin S., Datta S., Proposal for an all-spin logic device with built-in memory, Nature Nanotechnol., 5, 4, pp. 266-270, (2010); Rashba E.I., Theory of electrical spin injection: Tunnel contacts as a solution of the conductivity mismatch problem, Phys. Rev. B, 62, (2000); Mireles F., Kirczenow G., From classical to quantum spintronics: Theory of coherent spin injection and spin valve phenomena, Europhys. Lett., 59, 1, pp. 107-113, (2002); Das Sarma S., Fabian J., Hu X., Zutic I., Theoretical perspectives on spintronics and spin-polarized transport, IEEE Trans. Magn., 36, 5, pp. 2821-2826, (2000); Zutic I., Fabian J., Erwin S., Bipolar spintronics: Fundamentals and applications, IBM J. Res. Develop., 50, 1, pp. 121-139, (2006); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Landau L.D., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, 153, pp. 101-114, (1935); Gilbert T., Kelly J., Anomalous rotational damping in ferromagnetic sheets, Proc. Conf. Magn. Magn. Mater, pp. 253-263, (1955); Valet T., Fert A., Theory of the perpendicular magneto resistance in magnetic multilayers, Phys. Rev. B, 48, pp. 7099-7113, (1993); Brataas A., Nazarov Y.V., Bauer G.E.W., Finite-element theory of transport in ferromagnet-normal metal systems, Phys. Rev. Lett., 84, pp. 2481-2484, (2000); Brataas A., Bauer G.E., Kelly P.J., Non-collinear magnetoelec-tronics, Phys. Rep., 427, 4, pp. 157-255, (2006); Panagopoulos G., Augustine C., Roy K., A framework for simulating hybrid MTJ/CMOS circuits: Atoms to system approach, Proc. DATE, pp. 1443-1446, (2012); Behin-Aein B., Sarkar A., Srinivasan S., Datta S., Switching energy-delay of all spin logic devices, Appl. Phys. Lett., 98, 12, pp. 1235101-1235103, (2011); Quarles T., Newton A., Pederson D., Sangiovanni-Vincentelli A., SPICE 3 User Manual, (1993); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, 62, pp. 570-578, (2000); Beleggia M., Graef M.D., Millev Y.T., The equivalent ellipsoid of a magnetized body, J. Phys. D, Appl. Phys., 39, 5, (2006); Brown W., Thermal fluctuation of fine ferromagnetic particles, IEEE Trans. Magn., 15, 5, pp. 1196-1208, (1979); Lee S.-F., Holody W.P., Yang Q., Holody P., Loloee R., Schroeder P., Et al., Two-channel analysis of CPP-MR data for Ag/Co and AgSn/Co multilayers, J. Magn. Magn. Mater., 118, 1-2, (1993); Xia K., Kelly P.J., Bauer G.E.W., Brataas A., Turek I., Spin torques in ferromagnetic/normal-metal structures, Phys. Rev. B, 65, 22, pp. 2204011-2204014, (2002); Fabian J., Das Sarma S., Spin relaxation of conduction electrons in polyvalent metals: Theory and a realistic calculation, Phys. Rev. Lett., 81, pp. 5624-5627, (1998); Fabian J., Matos-Abiague A., Ertler C., Stano P., Zutic I., Semiconductor spintronics, Acta Phys. Slovaca, 57, pp. 565-907, (2007); Xiao J., Zangwill A., Stiles M.D., Macrospin models of spin transfer dynamics, Phys. Rev. B, 72, pp. 0144461-01444613, (2005); Hindmarsh A.C., ODEPACK, A Systematized Collection of ODE Solvers, 1, pp. 55-64, (1983); Behin-Aein B., Datta S., All-spin logic, Proc. Device Res. Conf., pp. 41-42, (2010); Rakheja S., Chang S.-C., Naeemi A., Impact of dimensional scaling and size effects on spin transport in copper and aluminum interconnects, IEEE Trans. Electron Devices, 60, 11, pp. 3913-3919, (2013)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-84899936240" +"Moumni M.; Tilioua M.","Moumni, M. (57195377066); Tilioua, M. (6507877823)","57195377066; 6507877823","On a Nonlocal Damping Model in Ferromagnetism","2015","Journal of Applied Mathematics","2015","","317947","","","","1","10.1155/2015/317947","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84938153195&doi=10.1155%2f2015%2f317947&partnerID=40&md5=ac87bd4123ff83a0231c628ec25dd0c0","CNRS, Universite de la Rochelle, La-Rochelle, 17000, France; FST Errachidia, Universite My Ismaïl, BP 509, Boutalamine, Errachidia, 52000, Morocco","Moumni M., CNRS, Universite de la Rochelle, La-Rochelle, 17000, France, FST Errachidia, Universite My Ismaïl, BP 509, Boutalamine, Errachidia, 52000, Morocco; Tilioua M., FST Errachidia, Universite My Ismaïl, BP 509, Boutalamine, Errachidia, 52000, Morocco","We consider a mathematical model describing nonlocal damping in magnetization dynamics. The model consists of a modified form of the Landau-Lifshitz-Gilbert (LLG) equation for the evolution of the magnetization vector in a rigid ferromagnet. We give a global existence result and characterize the long time behaviour of the obtained solutions. The sensitivity of the model with respect to large and small nonlocal damping parameters is also discussed. © 2015 M. Moumni and M. Tilioua.","","","","","","","","","Nembach H.T., Shaw J.M., Boone C.T., Silva T.J., Mode-and size-dependent Landau-Lifshitz damping in magneticnanostructures: Evidence for nonlocal damping, PhysicalReview Letters, 110, 11, (2013); Tserkovnyak Y., Hankiewicz E.M., Vignale G., Transversespin diffusion in ferromagnets, Physical Review B: CondensedMatter and Materials Physics, 79, 9, (2009); Ammari H., Halpern L., Hamdache K., Asymptoticbehaviour of thin ferromagnetic films, AsymptoticAnalysis, 24, 3-4, pp. 277-294, (2000); Hamdache K., Tilioua M., On the zero thickness limitof thin ferromagnetic films with surface anisotropy energy, Mathematical Models & Methods in Applied Sciences, 11, 8, pp. 1469-1490, (2001); Kruzk M., Prohl A., Recent developments in themodeling, analysis, and numerics of ferromagnetism, The SIAM Review, 48, 3, pp. 439-483, (2006); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Japan Journal of Applied Mathematics, 2, 1, pp. 69-84, (1985); Alouges F., Soyeur A., On global weak solutions forLandau-Lifshitz equations: Existence and nonuniqueness, NonlinearAnalysis. Theory, Methods & Applications, 18, 11, pp. 1071-1084, (1992); Podio-Guidugli P., Valente V., Existence of global-intimeweak solutions to a modified Gilbert equation, NonlinearAnalysis:Theory, Methods & Applications, 47, 1, pp. 147-158, (2001); Roubicek T., Tomassetti G., Zanini C., The Gilbert equationwith dry-friction-type damping, Journal of MathematicalAnalysis and Applications, 355, 2, pp. 453-468, (2009); Carbou G., Efendiev M.A., Fabrie P., Relaxedmodel for thehysteresis in micromagnetism, Proceedings of the Royal Societyof Edinburgh: SectionAMathematics, 139, 4, pp. 759-773, (2009); Tilioua M., Current-induced magnetization dynamics. Globalexistence of weak solutions, Journal of Mathematical Analysisand Applications, 373, 2, pp. 635-642, (2011); Hadda M., Tilioua M., On magnetization dynamics withinertial effects, Journal of EngineeringMathematics, 88, pp. 197-206, (2014); Carbou G., Fabrie P., Time average in micromagnetism, Journal of Differential Equations, 147, 2, pp. 383-409, (1998); Langlais M., Phillips D., Stabilization of solutions of nonlinearand degenerate evolution equations, Nonlinear Analysis.Theory, Methods & Applications, 9, 4, pp. 321-333, (1985); Evans L.C., Partial regularity for stationary harmonic mapsinto spheres, Archive for Rational Mechanics and Analysis, 116, 2, pp. 101-113, (1991); Lin F., Wang C., The Analysis of Harmonic Maps and TheirHeat Flows, (2008); Guo B., Ding S., Landau-Lifshitz Equations 1 OfFrontiers of Research with the Chinese Academy of Sciences, (2008); Sulem P.-L., Sulem C., Bardos C., On the continuous limitfor a system of classical spins, Communications in MathematicalPhysics, 107, 3, pp. 431-454, (1986); Alouges F., Jaisson P., Convergence of a finite elementdiscretization for the Landau-LIFshitz equations in micromagnetism, Mathematical Models & Methods in Applied Sciences, 16, 2, pp. 299-316, (2006); Bartels S., Prohl A., Convergence of an implicit finiteelement method for the Landau-LIFshitz-Gilbert equation, SIAM Journal on Numerical Analysis, 44, 4, pp. 1405-1419, (2006); Bartels S., Ko J., Prohl A., Numerical analysis of anexplicit approximation scheme for the Landau-LIFshitz-Gilbertequation, Mathematics of Computation, 77, 262, pp. 773-788, (2008)","","","Hindawi Publishing Corporation","","","","","","1110757X","","","","English","J. Appl. Math.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-84938153195" +"Tanaka H.; Nakamura K.; Ichinokura O.","Tanaka, Hideaki (55624472145); Nakamura, Kenji (55516112700); Ichinokura, Osamu (7003759274)","55624472145; 55516112700; 7003759274","Magnetic circuit model considering magnetic hysteresis","2015","Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)","192","3","","11","18","7","1","10.1002/eej.22733","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84927635440&doi=10.1002%2feej.22733&partnerID=40&md5=86d0a883e6222029ec1db42d3450edd2","Tohoku University, Japan","Tanaka H., Tohoku University, Japan; Nakamura K., Tohoku University, Japan; Ichinokura O., Tohoku University, Japan","Quantitative estimation of core loss considering magnetic hysteresis property is strongly required to develop high-efficient electrical machines. This paper presents a novel magnetic circuit model considering magnetic hysteresis. In the proposed model, dc hysteresis loss is calculated by the Landau-Lifshitz-Gilbert (LLG) equation, while classical and anomalous eddy current losses are calculated in the magnetic circuit. It is demonstrated that the hysteresis loop under PWM wave excitation can be expressed by the proposed model. The validity and effectiveness of the method are proved by comparing with measured values. © 2015 Wiley Periodicals, Inc.","iron loss; LLG equation; magnetic circuit model; magnetic hysteresis; PWM excitation","Circuit simulation; Magnetic hysteresis; Magnetic materials; Magnetism; Pulse width modulation; Timing circuits; Eddy current-loss; Electrical machine; Hysteresis loss; Iron loss; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic circuit model; Quantitative estimation; Magnetic circuits","","","","","","","Tajima K., Et al., Performance analysis of orthogonal-core converters based on a circuit system combined with a reluctance network model of the orthogonal core and the outer electric circuits, Trans IEEJ, 117 A, 2, pp. 155-160, (1997); Fujita K., Et al., Consideration of anomalous eddy current loss in magnetic circuits, J MSJ, 37, 2, pp. 44-47, (2013); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the Landau-Lifshitz-Gilbert equation for micromagnetics, Jpn J Appl Phys, 28, pp. 2485-2507, (1989); Furuya A., Et al., Iron Loss Analysis of Electrical Steel Sheet under High Frequency Excitation, (2013); Bertotti G., General properties of power losses in soft ferromagnetic materials, IEEE Trans Magn, 24, 1, pp. 621-630, (1988)","","","John Wiley and Sons Inc","","","","","","04247760","","EENJA","","English","Electr Eng Jpn","Article","Final","","Scopus","2-s2.0-84927635440" +"Panagopoulos G.; Augustine C.; Roy K.","Panagopoulos, Georgios (35435654600); Augustine, Charles (24779266100); Roy, Kaushik (57000621800)","35435654600; 24779266100; 57000621800","A framework for simulating hybrid MTJ/CMOS circuits: Atoms to system approach","2012","Proceedings -Design, Automation and Test in Europe, DATE","","","6176592","1443","1446","3","32","10.1109/date.2012.6176592","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84862081949&doi=10.1109%2fdate.2012.6176592&partnerID=40&md5=a46d14242702e54917315c4b792c3942","Dep. of ECE, Purdue University, United States","Panagopoulos G., Dep. of ECE, Purdue University, United States; Augustine C., Dep. of ECE, Purdue University, United States; Roy K., Dep. of ECE, Purdue University, United States","A simulation framework that can comprehend the impact of material changes at the device level to the system level design can be of great value, especially to evaluate the impact of emerging devices on various applications. To that effect, we have developed a SPICE-based hybrid MTJ/CMOS (magnetic tunnel junction) simulator, which can be used to explore new opportunities in large scale system design. In the proposed simulation framework, MTJ modeling is based on Landau-Lifshitz-Gilbert (LLG) equation, incorporating both spin-torque and external magnetic field(s). LLG along with heat diffusion equation, thermal variations, and electron transport are implemented using SPICE-inbuilt voltage dependent current sources and capacitors. The proposed simulation framework is flexible since the device dimensions such as MgO thickness and area, are user defined parameters. Furthermore, we have benchmarked this model with experiments in terms of switching current density (JC), switching time (T SWITCH) and tunneling magneto-resistance (TMR). Finally, we used our framework to simulate STT-MRAMs and magnetic flip-flops (MFF). © 2012 EDAA.","LLG; MTJ; simulation framework; SPICE; STT-MRAM","Electron transport properties; Flip flop circuits; Large scale systems; Magnesia; Magnetic devices; Magnetism; Systems analysis; Timing circuits; Tunnel junctions; External magnetic field; Heat diffusion equations; Landau-Lifshitz-Gilbert equations; Magnetic tunnel junction; Simulation framework; STT-MRAM; Switching current density; User-defined parameters; SPICE","","","","","","","Wolf S.A., Et al., The Promise of Nanomagnetics and Spintronics for Future Logic and Universal Memory, Proc. of IEEE, Dec. 2010; Augustine C., Et al., Numerical Analysis of Typical STT-MTJ Stacks for 1T-1R Memory Arrays, IEEE IEDM, pp. 544-547, (2010); Augustine C., Et al., Low-Power Functionality Enhanced Computation Architecture Using Spin-Based Devices, IEEE NANOARCH, (2011); Baibich M.N., Et al., Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices, PRLetters, pp. 2472-2475, (1988); Sakimura N., Sugibayashi T., Nebashi R., Kasai N., Nonvolatile Magnetic Flip-Flop for standby-power-free SoCs, IEEE CICC, (2008); Matsunaga S., Et al., Fabrication of A Nonvolatile Full Adder Based on Logic-in-Memory Architecture Using Magnetic Tunnel Junctions, (2008); Harms J.D., Et al., SPICE Macromodel of Spin-Torque-Transfer-Operated Magnetic Tunnel Junctions, IEEE T-ED, (2010); Nigam A., Et al., Self Consistent Parameterized Physical MTJ Compact Model for STT-RAM, pp. 423-426, (2010); Guo W., Et al., SPICE modelling of magnetic tunnel junctions written by spin-transfer torque, JAP, 43, (2010); Li J., Et al., Modeling of Failure Probability and Statistical Design of Spin-Torque Transfer Magnetic Random Access Memory (STT MRAM) Array for Yield Enhancement, IEEE DAC, (2008); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, PRB, (2000); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev., 130, 5, pp. 1677-1686, (1963); Li J., Et al., Design paradigm for robust spin-torque transfer magnetic RAM from circuit/architecture perspective, IEEE TVLSI, (2010); Diao Z., Et al., Spin-transfer torque switching in magnetic tunnel junctions and spintransfer torque random access memory, JPCM, (2007); Lee K., Kang S., Design Consideration of Magnetic Tunnel Junctions for Reliable high-Temperature Operation of STT-MRAM, IEEE TMAG, (2010); Yan L., Liou S., Wang D., Temperature dependence of magnetoresistance in magnetic tunnel junctions with different free layer structures, PRB, (2006)","G. Panagopoulos; Dep. of ECE, Purdue University, United States; email: gpanagop@purdue.edu","","Institute of Electrical and Electronics Engineers Inc.","ECSI; EDA Consortium (EDAC); European Design and Automation Association (EDAA); IEEE Council on Electronic Design Automation (CEDA); RAS; Special Interest Group on Design Automation (ACM-SIGDA)","15th Design, Automation and Test in Europe Conference and Exhibition, DATE 2012","12 March 2012 through 16 March 2012","Dresden","89544","15301591","978-398108018-6","","","English","Proc. Des. Autom. Test Eur. DATE","Conference paper","Final","","Scopus","2-s2.0-84862081949" +"Goulon J.; Brouder C.; Rogalev A.; Goujon G.; Wilhelm F.","Goulon, J. (7006514639); Brouder, Ch. (56259582000); Rogalev, A. (7005931453); Goujon, G. (12139210500); Wilhelm, F. (35493296000)","7006514639; 56259582000; 7005931453; 12139210500; 35493296000","Non-linear magnetization dynamics probed with X-rays: 1. Broken cylindrical symmetry of uniform modes","2014","Journal of Magnetism and Magnetic Materials","366","","","1","23","22","2","10.1016/j.jmmm.2014.03.074","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84901000842&doi=10.1016%2fj.jmmm.2014.03.074&partnerID=40&md5=1e339eeb0f08d9514843e1107e7e6262","European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France; Institut de Minéralogie et de Physique des Milieux Condensés, UMR-CNRS 7590, Université Paris VI, F-75252 Paris Cedex 05, 4 place Jussieu, France","Goulon J., European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France; Brouder C., Institut de Minéralogie et de Physique des Milieux Condensés, UMR-CNRS 7590, Université Paris VI, F-75252 Paris Cedex 05, 4 place Jussieu, France; Rogalev A., European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France; Goujon G., European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France; Wilhelm F., European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France","We discuss how X-ray magnetic circular dichroism (XMCD) and X-ray magnetic linear dichroism (XMLD) may complement each other to probe the nonlinear nature of the resonant precession of either spin or orbital magnetization components in aligned ferro-, ferri- or even antiferro-magnets. The Landau-Lifshitz-Gilbert (LLG) equation is solved in a rotating frame locked to the microwave pump field, while treating as time-dependent perturbations the terms which, in the formulation of the free energy density, break down the cylindrical symmetry of precession. Concretely, we analyze the time-oscillating deviations of the magnetization from the steady-state solutions of the LLG equation hereafter called SS-modes. At any perturbation order, one may derive magnetic dipole components which oscillate at harmonic frequencies of the pump frequency and could be probed with XMCD. Under bichromatic pumping, frequency mixing arises from a time-dependent Zeeman coupling between two rotating frames locked to each individual pump field. Similarly, we expect magnetic quadrupole components to oscillate at the same frequencies. For consistency, their derivation requires a perturbation calculation up to second order. The latter time-reversal even, rank-2 magnetic tensor components can be probed only with XMLD. Beyond the (reciprocal) linear dichroism classically measured in ferri- or antiferromagnetic samples, a non-reciprocal XMLD signal is to be expected when space parity is lost. Nonlinear effects strongly depend upon the relative orientations of the external bias field and of the pump field with respect to the symmetry axes of the magnetic system. This holds true for the foldover lineshape distortions, harmonic generation, frequency mixing or multiquanta excitations. © 2014 Elsevier B.V.","Nonreciprocal XMLD; Rotating frame LLG equation; XDMR; XMCD; XMLD","Dichroism; Harmonic generation; Locks (fasteners); Magnetization; Mixing; Pumps; LLG equation; Nonreciprocal; XDMR; XMCD; XMLD; X rays","","","","","","","Goulon J., Rogalev A., Wilhelm F., Jaouen N., Goulon-Ginet Ch., Goujon G., Ben Youssef J., Indenbom M.V., JETP Lett., 82, pp. 791-796, (2005); Goulon J., Rogalev A., Wilhelm F., Jaouen N., Goulon-Ginet Ch., Brouder Ch., Eur. Phys. J. B, 53, pp. 169-184, (2006); Goulon J., Rogalev A., Wilhelm F., Goulon-Ginet Ch., Goujon G., J. Synchrotron Rad., 14, pp. 257-271, (2007); Goulon J., Rogalev A., Wilhelm F., Goujon G., Brouder Ch., Yaresko A., Ben Youssef J., Indenbom M.V., J. Magn. Magn. Mater., 322, pp. 2308-2329, (2010); Goulon J., Rogalev A., Wilhelm F., Goujon G., Ben Youssef J., Gros C., Barbe J.-M., Guilard R., Int. J. Mol. Sci., 12, pp. 8797-8835, (2011); Rogalev A., Goulon J., Goujon G., Wilhelm F., Ogawa I., Idehara T., J. Infrared Milli. Terahz Waves, 33, pp. 777-793, (2012); Goulon J., Rogalev A., Wilhelm F., Goujon G., Yaresko A., Brouder Ch., Ben Youssef J., New J. Phys., 14, (2012); Bailey W.E., Cheng L., Keavney D.J., Kao C.-C., Vescovo E., D.A. Arena: Phys. Rev. B, 70, (2004); Arena D.A., Vescovo E., Kao C.-C., Guan Y., Bailey W.E., Phys. Rev. B, 74, (2006); Arena D.A., Vescovo E., Kao C.-C., Guan Y., Bailey W.E., J. Appl. Phys., 101, (2007); Guan Y., Bailey W.E., Vescovo E., Kao C.-C., Arena D.A., J. Magn. Magn. Mater., 312, pp. 374-378, (2007); Arena D.A., Ding Y., Vescovo E., Zohar S., Guan Y., Bailey W.E., Rev. Sci. Instrum., 80, (2009); Boero G., Rusponi S., Bencock P., Popovic R.S., Brune H., Gambardella P., Appl. Phys. Lett., 87, (2005); Boero G., Mouaziz S., Rusponi S., Bencok P., Nolting F., Stepanow S., Gambardella P., New J. Phys., 10, (2008); Boero G., Rusponi S., Bencok P., Meckenstock R., Thiele J.-U., Nolting F., Gambardella P., Phys. Rev. B, 79, (2009); Boero G., Rusponi S., Kavich J., Lodi Rizzini A., Piamonteze C., Nolting F., Tieg C., Thiele J.-U., Gambardella P., Rev. Sci. Instrum., 80; Marcham M.K., Keatley P.S., Neudert A., Hicken R.J., Cavill S.A., Shelford L.R., Van Der Laan G., Telling N.D., Childress J.R., Katine J.A., Shafer P., Arenholz E., J. Appl. Phys., 109, (2011); Bailey W.E., Cheng C., Knut R., Karis O., Auffret S., Zohar S., Keavney D., Warnicke P., Lee J.-S., Arena D.A., Nat. Comm., 4, (2013); Marcham M.K., Shelford L.R., Cavill S.A., Keatley P.S., Yu W., Shafer P., Neudert A., Childress J.R., Katine J.A., Arenholz E., Telling N.D., Van Der Laan G., Hicken R.J., Phys. Rev., 87, (2013); Schlomann E., Green J.J., Milano U., J. Appl. Phys., 31, (1960); Schlomann E., J. Appl. Phys., 33, pp. 527-537, (1962); Schlomann E., J. Phys. Soc. Jpn., 17, SUPPL. 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Rev., 57, pp. 522-527, (1940); Winter J., C.R. Acad. Sci. (Paris), 241, pp. 375-377, (1955); Margerie J., Brossel J., C.R. Acad. Sci. (Paris), 241, pp. 373-375, (1955); Keffer F., Spin Waves, Handbuch der Physik, 18, 2, pp. 1-268, (1966); Pippin J.E., Frequency Doubling and Mixing in Ferrites, pp. 1054-1061, (1956); Ayres W.P., IRE Trans., 7 MTT-, pp. 62-65, (1959); Morgenthaller F., J. Appl. Phys., 30, (1959); Jepsen R.L., Harmonic generation and frequency mixing in ferromagnetic insulators, scientific report afcrc-tn-58-150, J. Appl. Phys., 32, 1961, pp. 2627-2630, (1958); Risley A.S., Kaufman I., J. Appl. Phys., 33, pp. 1269-1270, (1962); Carra P., Konig H., Thole B.T., Altarelli M., Physica B, 192, pp. 182-190, (1993); Van Der Laan G., Phys. Rev. B, 55, pp. 8086-8089, (1997); Van Der Laan G., Phys. Rev. B, 57, pp. 112-115, (1998); Van Der Laan G., Phys. Rev. Lett., 82, pp. 640-643, (1999); Kunes J., Oppeneer P.M., Phys. Rev. B, 67, (2003); Arenholz E., Van Der Laan G., Chopdekar R.V., Susuki Y., Phys. Rev. B, 74, (2006); Van Der Laan G., Arenholz E., Chopdekar R.V., Susuki Y., Phys. Rev. B, 77, (2008); Judd B.R., Second Quantization in Atomic Spectroscopy, (1967); Borovik-Romanov A.S., Zhotikov V.G., Kreines N.M., Pankov A.A., Sov. Phys. JETP, 43, pp. 1002-1008, (1976); Borovik-Romanov A.S., Kreines N.M., Laiho R., Levola T., Zhotikov V.G., J. Phys. C: Solid. St. Phys., 13, pp. 879-885, (1980); Borovik A.S., Grimmer H., International Tables of Crystallography, D, pp. 105-149, (2006); Hansen P., Magnetic anisotropy and magneto-striction in garnets, Physics of Magnetic Garnets, Proceedings of the LXX International School of Physics (Enrico Fermi), pp. 56-133, (1978); Van Der Laan G., Thole B.T., Sawatzky G.A., Goedkoop J.B., Fuggle J.C., Esteva J.-M., Karnatak R., Remeika J.P., Dabkowska H.A., Phys. Rev. B, 34, pp. 6529-6531, (1986); Goulon J., Rogalev A., Gauthier C., Goulon-Ginet C., Paste S., Signorato R., Neuman C., Varga L., Malgrange C., J. Synchrotron Rad., 5, pp. 232-238, (1998); Elleaume P., J. Synchrotron Rad., 1, (1994); O'Dell T.H., The Electrodynamics of Magneto-electric Media, (1970); Velleaud G., Sangare B., Mercier M., J. Magn. Magn. Mater., 31-34, pp. 865-866, (1983); Takano S., Kita E., Siratori K., Kohn K., Kimura S., Tasaki A., J. Phys. Soc. (Jpn., pp. 288-293, (1991); Shastri S., Srinivasan G., Bichurin M.I., Petrov R.V., Tatarenko A.S., Phys. Rev. B, 70, (2004); Srinivasan G., Tatarenko A.S., Mathe V., Bichurin M.I., Eur. Phys. J. B, 71, pp. 371-375, (2009); Goulon J., Rogalev A., Wilhelm F., Goulon-Ginet C., Carra P., Marri I., Brouder C., J. Exptl. Theor. Phys., 92, pp. 402-431, (2003); Goulon J., Rogalev A., Brouder Ch., X-ray Detected Optical Activity, Comprehensive Chiroptical Spectroscopy, 1 VOL., pp. 457-491, (2012); Heinrich B., Cochran J.F., Adv. Phys., 42, pp. 523-639, (1993); Farle M., Rep. Prog. Phys., 61, pp. 755-826, (1998)","J. Goulon; European Synchrotron Radiation Facility (ESRF), F-38043 Grenoble Cedex, B.P. 220, France; email: goulon@esrf.fr","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84901000842" +"Baňas L.; Page M.; Praetorius D.; Rochat J.","Baňas, L'Ubomír (24079505700); Page, Marcus (55597570300); Praetorius, Dirk (6507452481); Rochat, Jonathan (56603992900)","24079505700; 55597570300; 6507452481; 56603992900","A decoupled and unconditionally convergent linear FEM integrator for the Landau-Lifshitz-Gilbert equation with magnetostriction","2014","IMA Journal of Numerical Analysis","34","4","","1361","1385","24","13","10.1093/imanum/drt050","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84988227369&doi=10.1093%2fimanum%2fdrt050&partnerID=40&md5=8ec572418a6603cdf71eda23146ad951","Faculty of Mathematics, Bielefeld University, Postfach 100131, Bielefeld, D-33501, Germany; Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; MATHICSE, École Polytechnique Fédérale de Lausanne, Station 8, Lausanne, CH-1015, Switzerland","Baňas L., Faculty of Mathematics, Bielefeld University, Postfach 100131, Bielefeld, D-33501, Germany; Page M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; Praetorius D., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; Rochat J., MATHICSE, École Polytechnique Fédérale de Lausanne, Station 8, Lausanne, CH-1015, Switzerland","To describe and simulate dynamic micromagnetic phenomena, we consider a coupled system of the nonlinear Landau-Lifshitz-Gilbert equation and the conservation of momentum equation. This coupling allows one to include magnetostrictive effects into the simulations. Existence of weak solutions has recently been shown in Carbou et al. (2011) (Global weak solutions for the Landau-Lifschitz equation with magnetostriction. Math. Meth. Appl. Sci., 34, 1274-1288). In our contribution, we give an alternate proof which additionally provides an effective numerical integrator. The latter is based on linear finite elements (FEs) in space and a linear-implicit Euler time-stepping. Despite the nonlinearity, only two linear systems have to be solved per timestep, and the integrator fully decouples both equations. Finally, we prove unconditional convergence - at least of a subsequence - towards, and hence existence of, a weak solution of the coupled system, as timestep size and spatial mesh size tend to zero. We conclude the work with numerical experiments, which study the discrete blow-up of the LLG equation as well as the influence of the magnetostrictive term on the discrete blow-up. © 2013 The authors. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.","ferromagnetism; LLG; magnetostriction; unconditionally convergent linear integrator","Control nonlinearities; Ferromagnetism; Finite element method; Linear systems; Magnetostriction; Magnetostrictive devices; Conservation of momentum; Existence of weak solutions; Landau-Lifschitz equations; Landau-Lifshitz-Gilbert equations; Linear finite elements; Magnetostrictive effect; Unconditional convergence; unconditionally convergent linear integrator; Nonlinear equations","","","","","Vienna Science and Technology Fund, WWTF, (MA09-029); Austrian Science Fund, FWF, (P21732)","M.P. and D.P. acknowledge financial support through the WWTF project MA09-029 and the FWF project P21732.","Alouges F., A new finite element scheme for Landau-Lifshitz equations, Discrete Contin. Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Kritsikis E., Toussaint J., A convergent finite element approximation for Landau-Lifshitz-Gilbert equation, Phys. B: Phys. Condens. Matter, 407, pp. 1-5, (2011); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Banas L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 46, pp. 1399-1422, (2008); Banas L.'., Page M., Praetorius D., A convergent linear finite-element scheme for the Maxwell-Landau-Lifshitz-Gilbert equation, ASC Report. Inst. Anal. Sci. Comp, (2013); Banas L.'., Slodicka M., Error estimates for Landau-Lifshitz-Gilbert equation with magnetostriction, Appl. Numer. Math., 56, pp. 1019-1039, (2006); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, pp. 220-238, (2005); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comp., 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 44, pp. 1405-1419, (2006); Brenner S.C., Scott L.R., The Mathematical Theory of Finite Element Methods, Corr, (2002); Bruckner F., Suess D., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Multiscale Modeling in Micromagnetics: Well-posedness and Numerical Integration, (2012); Carbou G., Efendiev M.A., Fabrie P., Global weak solutions for the Landau-Lifschitz equation with magnetostriction, Math. Meth. Appl. Sci., 34, pp. 1274-1288, (2011); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micro-magnetism, Arch. Comput. Methods Eng., 15, pp. 277-309, (2008); Garcia-Cervera C.J., Numerical micromagnetics: A review, Bol. Soc. Esp. Mat. Apl. SeMA, 39, pp. 103-135, (2007); Goldenits P., A Convergent Geometric Time Integrator to the Landau-Lifshitz-Gilbert Equation (In German), (2012); Goldenits P., Hrkac G., Mayr M., Praetorius D., Suess D., An effective integrator for the Landau-Lifshitz-Gilbert equation, Proc. of Mathmod 2012 Conf., 7, pp. 493-497, (2012); Goldenits P., Praetorius D., Suess D., Convergent geometric integrator for the Landau-Lifshitz-Gilbert equation in micromagnetics, PAMM: Proc. Appl. Math. Mech., 11, pp. 775-776, (2011); Hubert A., Schafer R., Magnetic Domains. The Analysis of Magnetic Microstructures, Corr. 3rd Printing, (1998); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev., 48, pp. 439-483, (2006); Le K.N., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz-Gilbert equations, Comput. Math. Appl., 66, pp. 1389-1402, (2012); Page M., On Dynamical Micromagnetism, (2013); Prohl A., Computational Micromagnetism, Advances in Numerical Mathematics, (2001); Rochat J., An Implicit Finite Element Method for the Landau-Lifshitz-Gilbert Equation with Exchange and Magnetostriction, (2012); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Japan J. Appl. Math., 2, pp. 69-84, (1985)","M. Page; Institute for Analysis and Scientific Computing, Vienna University of Technology, Wien, Wiedner Hauptstraße 8-10, A-1040, Austria; email: marcus.page@tuwien.ac.at","","Oxford University Press","","","","","","02724979","","","","English","IMA J. Numer. Anal.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84988227369" +"Wei J.; Feng H.; Zhu Z.; Liu Q.; Wang J.","Wei, J. (59045693500); Feng, H. (59089993900); Zhu, Z. (59056662700); Liu, Q. (7406292794); Wang, J. (55538378900)","59045693500; 59089993900; 59056662700; 7406292794; 55538378900","A new short-circuited coplanar waveguide to measuring the permeability of magnetic thin film: Comparison with short-circuited microstrip line","2015","2015 IEEE International Magnetics Conference, INTERMAG 2015","","","7156657","","","","0","10.1109/INTMAG.2015.7156657","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84942465584&doi=10.1109%2fINTMAG.2015.7156657&partnerID=40&md5=1920e62faed30d97d79dcc806c2fd810","Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China","Wei J., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China; Feng H., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China; Zhu Z., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China; Liu Q., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China; Wang J., Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou, China","Recently, soft magnetic thin films with high complex permeability μ, which can be used in the devices working at GHz range, have drew great attentions. A reliable and authentic permeability is very important for their applications. Microwave complex permeability μ=μ'+jμ' can be obtained by using the vector network analyzer (VNA). Generally, a jig was used to hold the magnetic thin films and detect their permeability spectra. The short-circuited microstrip line (MSL) was often as the preferred option because of its high sensitivity and other characteristics. [1] However, in some cases, the permeability measurements also require easy to operate the thin film in the jig. Two-port coplanar waveguide (CPW) was used to measure permeability due to its simple and open structure. [2] In this work, we proposed a short-circuited CPW jig, which can easy load the films and detect the permeability spectra. For comparison, short-circuited MSL is also used to measure permeability and the results are analyzed based on the Landau-Lifshitz-Gilbert (LLG) equation. © 2015 IEEE.","","Complex networks; Coplanar waveguides; Electric network analyzers; Magnetic circuits; Magnetic devices; Magnetic thin films; Magnetism; Microstrip lines; Thin films; Timing circuits; Complex permeability; Coplanar wave-guide (CPW); High sensitivity; Landau-Lifshitz-Gilbert equations; Permeability measurements; Permeability spectrum; Soft magnetic thin films; Vector network analyzers; Thin film circuits","","","","","","","Wei J., Wang J., Et al., An induction method to calculate the complex permeability of soft magnetic films, Rev. Sci. Instrum, 85, (2014); Bilzer C., Devolder T., Et al., Open-circuit one-port network analyzer ferromagnetic resonance, IEEE Trans. Magn, 44, 11, pp. 3265-3268, (2008)","","","Institute of Electrical and Electronics Engineers Inc.","","2015 IEEE International Magnetics Conference, INTERMAG 2015","11 May 2015 through 15 May 2015","Beijing","113931","","978-147997322-4","","","English","IEEE Int. Magn. Conf., INTERMAG","Conference paper","Final","","Scopus","2-s2.0-84942465584" +"Xu Z.; Sutaria K.B.; Yang C.; Chakrabarti C.; Cao Y.","Xu, Zihan (55550223800); Sutaria, Ketul B. (55301149100); Yang, Chengen (44261762300); Chakrabarti, Chaitali (35554384700); Cao, Yu (35301937800)","55550223800; 55301149100; 44261762300; 35554384700; 35301937800","Compact modeling of STT-MTJ for SPICE simulation","2013","European Solid-State Device Research Conference","","","6818887","338","341","3","9","10.1109/ESSDERC.2013.6818887","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84902158080&doi=10.1109%2fESSDERC.2013.6818887&partnerID=40&md5=40bbcff6a74cc2f2f4df9ddfdd6ae748","School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States","Xu Z., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States; Sutaria K.B., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States; Yang C., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States; Chakrabarti C., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States; Cao Y., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, United States","STT-MTJ is a promising device for future high-density and low-power integrated systems. To enable design exploration of STT-MTJ, this paper presents a fully compact model for efficient SPICE simulation. Derived from the fundamental LLG equation, the new model consists of RC elements that are closed-form solutions of device geometry and material properties. They support transient SPICE simulations, providing necessary details beyond the macromodel. The accuracy is validated with numerical results and published data. © 2013 IEEE.","","Closed form solutions; Compact model; Design Exploration; Device geometries; Integrated systems; LLG equation; Numerical results; SPICE simulations; SPICE","","","","","","","Wang X., Chen Y., Li H., Dimitrov D., Liu H., Spin torque random access memory down to 22nm technology, Trans. Magn., 44, 11, pp. 2479-2482, (2008); Sharad M., Augustine C., Panagopoulos G., Roy K., Spin-based neuron model with domain-wall magnets as synapse, Trans. Nanotechnology, 11, 4, pp. 843-853, (2012); Wang P., Zhang W., Joshi R., Kanj R., Chen Y., A thermal and process variation aware MTJ switching model and its applications in soft error analysis, ICCAD, pp. 720-727, (2012); Chun K.C., Zhao J., Harms J.D., Kim T.-H., Wang J.-P., Kim C.H., A scaling roadmap and performance evaluation of in-plane and perpendicular MTJ based STT-MRAMs for high-density cache memory, JSSC, 48, 2, pp. 598-610, (2013); Ralph D.C., Stiles M.D., Current perspectives: Spin transfer torques, J. MMM, 320, pp. 1190-1216, (2008); Kammerer J.-B., Madec M., Hebrard L., Compact modeling of a magnetic tunnel junction - Part I: Dynamic magnetization model, TED, 57, 6, pp. 1408-1415, (2010); Lu H.M., Zheng W.T., Jiang Q., Saturation magnetization of ferromagnetic and ferrimagnetic nanocrystals at room temperature, Journal of Physics D: Applied Physics, 40, 2, pp. 320-325, (2007); Faber L.-B., Zhao W., Klein J.-O., Devolder T., Chappert C., Dynamic compact model of spin-transfer torque based magnetic tunnel junction (MTJ), DTIS, pp. 130-135, (2009); Madec M., Kammerer J.-B., Hebrard L.L., Compact modeling of a magnetic tunnel junction - Part II: Tunneling current model, TED, 57, 6, pp. 1416-1424, (2010); Diao Z., Et al., Spin-transfer torque switching in magnetic tunnel junctions and spin-transfer torque random access memory, J. Phys.: Condensed Matter, 19, 16, (2007); Lin C.J., Et al., 45nm low power CMOS logic compatible embedded STT MRAM utilizing a reverse-connection 1T/1MTJ cell, IEDM, (2009)","","","IEEE Computer Society","Cadence Academic Network; eniac; et al.; Infineon; Mentor Graphics; Ministerul Educatiei Nationale","43rd European Solid-State Device Research Conference, ESSDERC 2013","16 September 2013 through 20 September 2013","Bucharest","105422","19308876","978-147990649-9","","","English","European Solid-State Device Res. Conf.","Conference paper","Final","","Scopus","2-s2.0-84902158080" +"Seemann K.; Leiste H.; Krüger K.","Seemann, K. (6701634406); Leiste, H. (55885138500); Krüger, K. (55805281800)","6701634406; 55885138500; 55805281800","Ferromagnetic resonance frequency increase and resonance line broadening of a ferromagnetic Fe-Co-Hf-N film with in-plane uniaxial anisotropy by high-frequency field perturbation","2013","Journal of Magnetism and Magnetic Materials","345","","","36","40","4","13","10.1016/j.jmmm.2013.06.003","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84885087215&doi=10.1016%2fj.jmmm.2013.06.003&partnerID=40&md5=2c48e368307ff36a60ea8bf317891418","Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany","Seemann K., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; Leiste H., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; Krüger K., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany","Soft ferromagnetic Fe-Co-Hf-N films, produced by reactive r.f. magnetron sputtering, are useful to study the ferromagnetic resonance (FMR) by means of frequency domain permeability measurements up to the GHz range. Films with the composition Fe33Co43Hf10N14 exhibit a saturation polarisation Js of around 1.35 T. They are consequently considered as being uniformly magnetised due to an in-plane uniaxial anisotropy of approximately μ0Hu≈4.5 m T after annealing them, e.g., at 400 1C in a static magnetic field for 1 h. Being exposed to a high-frequency field, the precession of magnetic moments leads to a marked frequency-dependent permeability with a sharp Lorentzian shaped imaginary part at around 2.33 GHz (natural resonance peak), which is in a very good agreement with the modified Landau-Lifschitz-Gilbert (LLG) differential equation. A slightly increased FMR frequency and a clear increase in the resonance line broadening due to an increase of the exciting high-frequency power (1-25.1 mW), considered as an additional perturbation of the precessing system of magnetic moments, could be discovered. By solving the homogenous LLG differential equation with respect to the in-plane uniaxial anisotropy, it was revealed that the high-frequency field perturbation impacts the resonance peak position f FMR and resonance line broadening δfFMR characterised by a completed damping parameter α=α eff+δα. Adapted from this result, the increase in f FMR and decrease in lifetime of the excited level of magnetic moments associated with δfFMR, similar to a spin-1/2 particle in a static magnetic field, was theoretically elaborated as well as compared with experimental data. © 2013 Elsevier B.V. All rights reserved.","Ferromagnetic film; Ferromagnetic resonance; Line broadening; Magnon processes","Anisotropy; Cobalt; Critical currents; Differential equations; Ferromagnetic materials; Ferromagnetism; Frequency domain analysis; Hafnium; Magnetic fields; Magnetic moments; Magnetism; Metallic films; Resonance; Ferromagnetic films; Ferromagnetic resonance (FMR); Ferromagnetic resonance frequency; Line broadening; Permeability measurements; R.F. magnetron sputtering; Resonance peak position; Static magnetic fields; Ferromagnetic resonance","","","","","Karlsruhe Institute of Technology, KIT; Deutsche Forschungsgemeinschaft, DFG","Funding text 1: This work was partially carried out with the support of the Karlsruhe Nano Micro Facility (KNMF, www.knmf.kit.edu), a Helmholtz research infrastructure at Karlsruhe Institute of Technology (KIT, www.kit.edu). ; Funding text 2: The research activities were also partially carried out within the Joint Research Project “HAUT” No. 1299 through the financial support of the Deutsche Forschungsgemeinschaft DFG and is gratefully acknowledged.","Gilbert T.L., IEEE Transactions on Magnetics, 40, (2004); Seemann K., Leiste H., Bekker V., Journal of Magnetism and Magnetic Materials, 278, (2004); Seemann K., Leiste H., Kruger K., Journal of Magnetism and Magnetic Materials, 324, (2012); Damon R.W., Review of Modern Physics, 25, (1953); Bloembergen N., Wang S., Physical Review, 93, (1954); Suhl H., Journal of Physics and Chemistry of Solids, 1, (1957); Suhl H., Journal of Applied Physics, 30, (1959); Loos J., Linzen A., Dusek J., Czechoslovak Journal of Physics, B20, (1970); Seemann K., Leiste H., Klever Ch., Journal of Magnetism and Magnetic Materials, 321, (2009); Bekker V., Seemann K., Leiste H., Journal of Magnetism and Magnetic Materials, 270, (2004); Liu Y., Chen L., Tan C.Y., Liu H.J., Ong C.K., Review of Scientific Instruments, 76, (2005)","K. Seemann; Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; email: klaus.seemann@kit.edu","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84885087215" +"Jabeur K.; Bernard-Granger F.; Di Pendina G.; Prenat G.; Dieny B.","Jabeur, K. (36349793700); Bernard-Granger, F. (55217807100); Di Pendina, G. (16635543800); Prenat, G. (55999359600); Dieny, B. (7005208439)","36349793700; 55217807100; 16635543800; 55999359600; 7005208439","Comparison of Verilog-A compact modelling strategies for spintronic devices","2014","Electronics Letters","50","19","","1353","1355","2","23","10.1049/el.2014.1083","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84907152431&doi=10.1049%2fel.2014.1083&partnerID=40&md5=158060554468f06a2b48709984591ec6","University of Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France; CNRS, INAC-SPINTEC, CEA, 17 rue des Martyrs, Grenoble Cedex 9, 38054, France","Jabeur K., University of Grenoble Alpes, INAC-SPINTEC, Grenoble, F-38000, France; Bernard-Granger F., CNRS, INAC-SPINTEC, CEA, 17 rue des Martyrs, Grenoble Cedex 9, 38054, France; Di Pendina G., CNRS, INAC-SPINTEC, CEA, 17 rue des Martyrs, Grenoble Cedex 9, 38054, France; Prenat G., CNRS, INAC-SPINTEC, CEA, 17 rue des Martyrs, Grenoble Cedex 9, 38054, France; Dieny B., CNRS, INAC-SPINTEC, CEA, 17 rue des Martyrs, Grenoble Cedex 9, 38054, France","Magnetic random access memory based on magnetic tunnel junctions (MTJs) is among the most attractive technologies of emerging non-volatile memories. However, the integration of spin-based devices in integrated circuits is still hindered by a lack of established standard electrical simulator models. Many of such models have been proposed during the past decade which can be classified into two categories: the first ones are based on the physical Landau-Lifshitz-Gilbert (LLG) equation describing real-time MTJ magnetic switching dynamics; the second one uses analytical expressions for switching thresholds derived from the LLG equation. The aim of this reported work was to investigate for the first time the capability of each strategy to fulfil the need of industrial standard electrical simulation tools and pave the path towards a standard industrial model. Multi-simulator compatibility, efficient runtime, accuracy and reliability are the three main assets of a device model. It is shown that using the Cadence® tools suite with the Spectre® simulator, the LLG modelling strategy overcomes the analytical approach in terms of accuracy and speed with a 7× faster runtime. Both models require nearly the same hardware memory resources. © The Institution of Engineering and Technology 2014.","","Magnetic storage; Magnetism; Simulators; Tunnel junctions; Analytical expressions; Electrical simulation; Emerging non-volatile memory; Landau-Lifshitz-Gilbert equations; Magnetic random access memory; Magnetic tunnel junction; Modelling strategies; Switching thresholds; Random access storage","","","","","European Commission, (318144)","","Harms J.D., Ebrahimi F., Yao X., Wang J.-P., SPICE macrodel of spin-torque-transfer-operated magnetic tunnel junctions, IEEE Trans. Electron Devices, 57, 6, pp. 1425-1430, (2010); Panagopoulos G.D., Augustine C., Roy K., Physics-based SPICE-compatible compact model for simulating hybrid MTJ/CMOS circuits, IEEE Trans. Electron Devices, 60, 9, pp. 2808-2814, (2013); Guo W., Prenat G., Javerliac V., El Baraji M., De Mestier N., Baraduc C., Dieny B., SPICE modelling of magnetic tunnel junctions written by spin-transfer torque, J. Phys. D, Appl. Phys., 43, 21, (2010); Mierzwinsk M., Halloran P.O., Troyanovsky B., Dutton R., Changing the paradigm for compact model integration in circuit simulators using Verilog-A, Tech. Proc. of 2003 Nanotechnology Conf. and Trade Show, 2, pp. 376-379, (2003); Jabeur K., Prenat G., Di Pendina G., Buda Prejbeanu L.D., Prejbeanu I.L., Dieny B., Compact model of a three-terminal MRAM device based on spin orbit torque switching, Proc. of 2013 Semiconductor Conf., (2013); Zhang Y., Zhao W., Ravelosona D., Klein J.-O., Kim J.-V., Chappert C., A compact model of perpendicular magnetic anisotropy magnetic tunnel junction, IEEE Trans. Electron Device, 59, pp. 819-826, (2012); Jabeur K., Di Pendina G., Prenat G., Buda-Prejbeanu L.D., Dieny B., Compact modeling of a magnetic tunnel junction based on spin orbit torque, IEEE Trans. Magn.; Coram G.J., How to (and how not to) write a compact model in Verilog-A, Proc. 2004 IEEE Int. Behavioral Modeling and Simulation Conf. (BMAS 2004), (2004); Depeyrot G., Poullet F., Dumas B., Verilog-A compact model coding whitepaper, Proc. Nanotech 2010, 2, pp. 821-824, (2010)","","","Institution of Engineering and Technology","","","","","","00135194","","ELLEA","","English","Electron. Lett.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-84907152431" +"Liu T.; Zhou P.H.; Liang D.F.; Xie J.L.; Deng L.J.","Liu, T. (56703868000); Zhou, P.H. (8278501100); Liang, D.F. (16063815900); Xie, J.L. (7402994553); Deng, L.J. (15070111700)","56703868000; 8278501100; 16063815900; 7402994553; 15070111700","Multi-resonances behavior of Ni nanobelt/paraffin composites at microwave frequencies","2012","Journal of Alloys and Compounds","524","","","1","4","3","14","10.1016/j.jallcom.2012.01.157","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84857671374&doi=10.1016%2fj.jallcom.2012.01.157&partnerID=40&md5=fb80a87fc32969fded5187332da2305f","State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China","Liu T., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China; Zhou P.H., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China; Liang D.F., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China; Xie J.L., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China; Deng L.J., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China","Ni nanobelts are synthesized through a facile hydrothermal method to form magnetic composites for high frequency applications. Four resonance peaks of the relative complex permeability illustrate the multi-resonance behavior in Ni nanobelt/paraffin composites in a frequency range of 2-18 GHz. The resonance absorption characteristics are analyzed by fitting the permeability spectrum with the well-known Landau-Lifshitz-Gilbert (LLG) equation and Maxwell-Garnett mixing rule. Unlike previous studies, LLG equation has been deduced on account of the random distribution of Ni nanobelts in paraffin matrix first, and then applied for data fitting and resonance identification. Correspondingly, the first band is attributed to natural resonance, while the other three bands are considered to originate from non-uniform exchange resonance. © 2012 Elsevier B.V.","Landau-Lifshitz-Gilbert equation; Maxwell-Garnett mixing rule; Natural resonance; Ni nanobelt; Non-uniform exchange resonance","Maxwell equations; Mixing; Nanobelts; Paraffin waxes; Paraffins; Complex permeability; Data fittings; Frequency ranges; High-frequency applications; Hydrothermal methods; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic composites; Maxwell-Garnett mixing; Multiresonance; Natural resonance; Permeability spectrum; Random distribution; Resonance absorption; Resonance peak; Resonance","","","","","National Natural Science Foundation of China, NSFC, (51025208, 61001026); Fundamental Research Funds for the Central Universities","This work was supported by “the Fundamental Research Funds for the Central Universities ” and the NSFC (Grant Nos. 61001026 and 51025208 ).","Acher O., Dubourg S., Phys. Rev. B, 77, (2008); Kittel C., Phys. Rev., 73, pp. 155-161, (1948); Qiao L., Wen F.S., Wei J.Q., Wang J.B., Li F.S., J. Appl. Phys., 103, (2008); Sihvola A.H., Electromagnetic Mixing Formulas and Application, (1999); Yan L.G., Wang J.B., Han X.H., Ren Y., Liu Q.F., Li F.S., Nanotechnology, 21, (2010); Liu Z.P., Li S., Yang Y., Peng S., Hu Z.K., Qian Y., Adv. Mater., 22, pp. 1946-1948, (2003); Zhong W.H., Sun C.Q., Li S., Bai H.L., Jiang E.Y., Acta Mater., 53, pp. 3207-3214, (2005); Gao B., Qiao L., Wang J.B., Liu Q.F., Li F.S., Feng J., Xue D.S., J. Phys. D: Appl. Phys., 41, (2008); Ma J., Li J.G., Ni X., Zhang X.D., Huang J.J., Appl. Phys. Lett., 95, (2009); Liao S.B., Ferromagnetic Physics, 3, (2000); Aharoni A., J. Appl. Phys., 69, pp. 7762-7764, (1991); Toneguzzo Ph., Viau G., Acher O., Guillet F., Bruneton E., Vincent F.F., Fievet F., J. Mater. Sci., 35, pp. 3767-3784, (2000); Deng L.J., Zhou P.H., Xie J.L., Zhang L., J. Appl. Phys., 101, (2007); Qiao L., Han X.H., Gao B., Wang J.B., Wen F.S., Li F.S., J. Appl. Phys., 105, (2009); Osborn J.A., Phys. Rev., 67, pp. 351-357, (1945); Rozanov K.N., Osipov A.V., Petrov D.A., Starostenko S.N., Yelsukov E.P., J. Magn. Magn. Mater., 321, pp. 738-741, (2009); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Ma F., Qin Y., Li Y.Z., Appl. Phys. Lett., 96, (2010); Wen F.S., Yi H.B., Qiao L., Zheng H., Zhou D., Li F.S., Appl. Phys. Lett., 92, (2008)","P.H. Zhou; State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China; email: zhouph1981@163.com","","","","","","","","09258388","","JALCE","","English","J Alloys Compd","Article","Final","","Scopus","2-s2.0-84857671374" +"Gutiérrez S.; De Laire A.","Gutiérrez, Susana (56239017900); De Laire, André (26040620600)","56239017900; 26040620600","Self-similar solutions of the one-dimensional Landau-Lifshitz-Gilbert equation","2015","Nonlinearity","28","5","1307","1307","1350","43","8","10.1088/0951-7715/28/5/1307","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84946160806&doi=10.1088%2f0951-7715%2f28%2f5%2f1307&partnerID=40&md5=2f92fa72eacc634b7e6f5c0e9cfd85c9","School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; Laboratoire Paul Painlevé, Université Lille 1, Villeneuve d'Ascq Cedex, 59655, France","Gutiérrez S., School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom; De Laire A., Laboratoire Paul Painlevé, Université Lille 1, Villeneuve d'Ascq Cedex, 59655, France","We consider the one-dimensional Landau-Lifshitz-Gilbert (LLG) equation, a model describing the dynamics for the spin in ferromagnetic materials. Our main aim is the analytical study of the bi-parametric family of self-similar solutions of this model. In the presence of damping, our construction provides a family of global solutions of the LLG equation which are associated with discontinuous initial data of infinite (total) energy, and which are smooth and have finite energy for all positive times. Special emphasis will be given to the behaviour of this family of solutions with respect to the Gilbert damping parameter. We would like to emphasize that our analysis also includes the study of self-similar solutions of the Schrödinger map and the heat flow for harmonic maps into the 2-sphere as special cases. In particular, the results presented here recover some of the previously known results in the setting of the 1D-Schrödinger map equation. © 2015 IOP Publishing Ltd & London Mathematical Society.","asymptotics; ferromagnetic spin chain; heat-flow for harmonic maps; Landau-Lifshitz-Gilbert equation; Schrödinger maps; self-similar solutions","","","","","","Engineering and Physical Sciences Research Council, EPSRC; Engineering and Physical Sciences Research Council, EPSRC, (EP/J01155X/1); Horizon 2020 Framework Programme, H2020, (669689); , (ANR-11-LABX-0007)","","Abramowitz M., Stegun I.A., Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables National Bureau of Standards Applied Mathematics Series, 55, (1964); Banica V., Vega L., On the Dirac delta as initial condition for nonlinear Schrödinger equations, Ann. Inst. H. Poincaré Anal. Non Linéaire, 25, pp. 697-711, (2008); Banica V., Vega L., On the stability of a singular vortex dynamics, Commun. Math. Phys., 286, pp. 593-627, (2009); Banica V., Vega L., Scattering for 1D cubic NLS and singular vortex dynamics, J. Eur. Math. Soc., 14, pp. 209-253, (2012); Banica V., Vega L., Stability of the self-similar dynamics of a vortex filament, Arch. Ration. Mech. Anal., 210, pp. 673-712, (2013); Biernat P., Bizon P., Shrinkers, expanders, and the unique continuation beyond generic blowup in the heat flow for harmonic maps between spheres, Nonlinearity, 24, 8, pp. 2211-2228, (2011); Bizon P., Wasserman A., Nonexistence of shrinkers for the harmonic map flow in higher dimensions, Int. Math. Res. Not. IMRN; Brezis H., Opérateurs Maximaux Monotones et Semi-groupes de Contractions dans les Espaces de Hilbert, 5, (1973); Buttke T.F., A numerical study of superfluid turbulence in the self-induction approximation, J. Comput. Phys., 76, pp. 301-326, (1988); Coddington E.A., Levinson N., Theory of Ordinary Differential Equations, (1955); Daniel M., Lakshmanan M., Soliton damping and energy loss in the classical continuum Heisenberg spin chain, Phys. Rev. B, 24, pp. 6751-6754, (1981); Daniel M., Lakshmanan M., Perturbation of solitons in the classical continuum isotropic Heisenberg spin system, Physica A, 120, pp. 125-152, (1983); Darboux G., Leçcons sur la Théorie Générale des Surfaces. I, II, (1993); De La Hoz F., Garcia-Cervera C.J., Vega L., A numerical study of the self-similar solutions of the Schrödinger map, SIAM J. Appl. Math., 70, pp. 1047-1077, (2009); Germain P., Rupflin M., Selfsimilar expanders of the harmonic map flow, Ann. Inst. H. Poincaré Anal. Non Linéaire, 28, pp. 743-773, (2011); Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetization field, Phys. Rev., 100, (1955); Grunrock A., Bi- and trilinear Schrödinger estimates in one space dimension with applications to cubic NLS and DNLS, Int. Math. Res. Not., 41, pp. 2525-2558, (2005); Guan M., Gustafson S., Kang K., Tsai T.-P., Global questions for map evolution equations, Singularities in PDE and the Calculus of Variations CRM Proc. Lecture Notes, 44, pp. 61-74, (2008); Guo B., Ding S., Landau-Lifshitz Equations Frontiers of Research with the Chinese Academy of Sciences, 1, (2008); Gutierrez S., Rivas J., Vega L., Formation of singularities and self-similar vortex motion under the localized induction approximation, Commun. Partial Differ. Eqn., 28, pp. 927-968, (2003); Gutierrez S., Vega L., Self-similar solutions of the localized induction approximation: Singularity formation, Nonlinearity, 17, 6, pp. 2091-2136, (2004); Hartman P., Ordinary Differential Equations, (1964); Hasimoto H., A soliton on a vortex filament, J. Fluid Mech., 51, pp. 477-485, (1972); Hubert A., Schafer R., Magnetic Domains: The Analysis of Magnetic Microstructures, (1998); Kenig C.E., Ponce G., Vega L., On the ill-posedness of some canonical dispersive equations, Duke Math. J., 106, pp. 617-633, (2001); Kosevich A.M., Ivanov B.A., Kovalev A.S., Magnetic solitons, Phys. Rep., 194, pp. 117-238, (1990); Lakshmanan M., The fascinating world of the Landau-Lifshitz-Gilbert equation: An overview, Phil. Trans. R. Soc. A, 369, pp. 1280-1300, (2011); Lakshmanan M., Ruijgrok T.W., Thompson C.J., On the dynamics of a continuum spin system, Physica A, 84, pp. 577-590, (1976); Lamb G.L., Elements of Soliton Theory (Pure and Applied Mathematics), (1980); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Lin F., Wang C., The Analysis of Harmonic Maps and Their Heat Flows, (2008); Lipniacki T., Shape-preserving solutions for quantum vortex motion under localized induction approximation, Phys. Fluids, 15, pp. 1381-1395, (2003); Schwarz K.W., Three-dimensional vortex dynamics in superfluid 4He: Line-line and line-boundary interactions, Phys. Rev. B, 31, pp. 5782-5804, (1985); Steiner M., Villain J., Windsor C.G., Theoretical and experimental studies on one-dimensional magnetic systems, Adv. Phys., 25, pp. 87-209, (1976); Struik D.J., Lectures on Classical Differential Geometry, (1950); Van Gorder R.A., Self-similar vortex dynamics in superfluid 4He under the Cartesian representation of the Hall-Vinen model including superfluid friction, Phys. Fluids, 25, (2013); Vargas A., Vega L., Global wellposedness for 1D non-linear Schrödinger equation for data with an infinite L2 norm, J. Math. Pure. Appl., 80, pp. 1029-1044, (2001)","","","Institute of Physics Publishing","","","","","","09517715","","","","English","Nonlinearity","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-84946160806" +"Yang X.; Wei J.-Q.; Li X.-H.; Gong L.-Q.; Wang T.; Li F.-S.","Yang, Xu (57191642127); Wei, Jian-Qiang (57217287930); Li, Xing-Hua (55643973000); Gong, Lu-Qian (36727482800); Wang, Tao (58127626200); Li, Fa-Shen (21741072200)","57191642127; 57217287930; 55643973000; 36727482800; 58127626200; 21741072200","Thickness dependence of microwave magnetic properties in electrodeposited FeCo soft magnetic films with in-plane anisotropy","2012","Physica B: Condensed Matter","407","3","","555","559","4","20","10.1016/j.physb.2011.11.049","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84655169825&doi=10.1016%2fj.physb.2011.11.049&partnerID=40&md5=186b7d13b8e81bb1759a4665f04ab2c9","Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China","Yang X., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; Wei J.-Q., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; Li X.-H., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; Gong L.-Q., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; Wang T., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; Li F.-S., Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China","In this work, the thickness effect of Fe 52Co 48 soft magnetic films with in-plane anisotropy on static and microwave magnetic properties was investigated. The hysteresis loop results indicated that the static in-plane uniaxial anisotropy field increased from almost 060 Oe with increasing film thickness from 100 to 540 nm and well-defined in-plane uniaxial magnetic anisotropy can be obtained as the thickness reached 540 nm or larger. Based on LandauLifshitzGilbert (LLG) equation, the microwave complex permeability spectra were analyzed and well fitted. The LLG curve-fitting results indicated that the initial permeability increased from 106 to 142 and the resonant frequency was shifted from 4.95 to 4.29 GHz as the film thickness was varied from 540 to 1500 nm. Moreover, it was found that there was a discrepancy between the static and the dynamically determined anisotropy field, which can be explained by introducing an additional effective isotropic ripple field. The decreased ripple field was suggested to result in a significant decrease of damping coefficient from 0.109 to 0.038. © 2011 Elsevier B.V. All rights reserved.","Electrodeposition; Film thickness; Microwave permeability; Soft magnetic film; Surface roughness","Cobalt; Curve fitting; Electrodeposition; Ferrites; Film thickness; Magnetic devices; Magnetic films; Magnetic materials; Magnetism; Microwaves; Natural frequencies; Surface roughness; Anisotropy field; Complex permeability spectra; Damping coefficients; In-plane; In-plane anisotropy; Initial permeability; Microwave magnetic properties; Microwave permeability; Soft magnetic films; Thickness dependence; Thickness effect; Uniaxial anisotropy fields; Uniaxial magnetic anisotropy; Magnetic anisotropy","","","","","National Natural Science Foundation of China, NSFC, (10774061); National Natural Science Foundation of China, NSFC","This work is supported by the National Natural Science Foundation of China under Grant no. 10774061 .","Acher O., J. Magn. Magn. Mater., 321, (2009); Sohn J., Han S.H., Kim K.H., Yamaguchi M., Lim S.H., J. Magn. Magn. Mater., 311, (2007); Wang S.X., Sun N.X., Yamaguchi M., Yabukami S., Nature, 407, (2000); Ikeda K., Kobayashi K., Ohta K., Kondo R., Suzuki T., Fujimoto M., IEEE Trans. Magn., 39, (2003); Phuoc N.N., Xu F., Ong C.K., Appl. Phys. Lett., 94, (2009); Yao D.S., Ge S.H., Zhou X.Y., Physica B, 405, (2010); Snoek J.L., Physica, 14, (1948); Wolf I.W., J. Appl. Phys., 33, (1962); Tanahashi K., Maeda M., J. Appl. Phys., 56, (1984); Liao S.H., IEEE Trans. Magn., 23, (1987); Kakuno E.M., Mosca D.H., Mazzaro I., Mattoso N., Schreiner W.H., Gomes M.A.B., J. Electrochem. Soc., 144, (1997); Osaka T., Takai M., Hayashi K., Ohashi K., Saito M., Yamada K., Nature, 392, (1998); Liu X.M., Zangari G., J. Appl. Phys., 87, (2000); Lallemand F., Ricq L., Deschaseaux E., De Vettor L., Bercot P., Surf. Coat. Technol., 197, (2005); Liu X.M., Rantschler J.O., Alexander C., Zangari G., IEEE Trans. Magn., 39, (2003); Mizutani S., Yokoshima T., Nam H., Nakanishi T., Osaka T., Yamazaki Y., IEEE Trans. Magn., 36, (2000); Rhen F.M.F., McCloskey P., O'Donnell T., Roy S., J. Magn. Magn. Mater., 320, (2008); Liu X.M., Zangari G., Shamsuzzoha M., J. Electrochem. Soc., 150, (2003); Yang X., Gong L.Q., Wei J.Q., Qiao L., Wang T., Li F.S., J. Phys. D: Appl. Phys., 43, (2010); Bekker V., Seemann K., Leiste H., J. Magn. Magn. Mater., 270, (2004); Neel L., J. Phys Radium, 17, (1956); Tabakovic I., Inturi V., Riemer S., J. Electrochem. Soc., 149, (2002); Neudert A., McCord J., Schafer R., Schultz L., J. Appl. Phys., 95, (2004); Goto M., Tange H., Kamimori T., J. Magn. Magn. Mater., 62, (1986); Neel L., J. Phys. Radium, 15, (1954); Chechenin N.G., Du Marchie Van Voorthuysen E.H., De Hosson J.Th.M., Boerma D.O., J. Magn. Magn. Mater., 290-291, (2005); Katada H., Shimatsu T., Watanabe I., Muraoka H., IEEE Trans. Magn., 36, (2000); Zeng Q., Baker I., Sun Y., Cui J.B., Daghlian C.P., J. Appl. Phys., 99, (2006); Xue D.S., Li F.S., Fan X.L., Wen F.S., Chin. Phys. Lett., 25, (2008); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Youssef J.B., Jacquart P.M., Vukadinovic N., Le Gall H., IEEE Trans. Magn., 38, (2002); Jacquart P.M., Roux L., J. Magn. Magn. Mater., 281, (2004); Liu Y., Liu Z.W., Tan C.Y., Ong C.K., J. Appl. Phys., 100, (2006); Lopusnik R., Nibarger J.P., Silva T.J., Celinski Z., Appl. Phys. Lett., 83, (2003); Phuoc N.N., Hung L.T., Ong C.K., J. Alloys Compd., 509, (2011); Phuoc N.N., Ong C.K., Physica B, 406, (2011); Hoffmann H., IEEE Trans. Magn., 4, (1968); Xu F., Zhang X.Y., Ma Y.G., Phuoc N.N., Chen X., Ong C.K., J. Phys. D: Appl. Phys., 42, (2009); Kittel C., Phys. Rev., 71, (1947); Fannin P.C., Marin C.N., Malaescu I., J. Phys.:Condens. Matter, 15, (2003)","T. Wang; Key Laboratory for Magnetism and Magnetic Materials, Lanzhou University, Ministry of Education, Lanzhou 730000, China; email: wtao@lzu.edu.cn","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-84655169825" +"Kuek N.S.; Liew A.C.; Schamiloglu E.; Rossi J.O.","Kuek, Ngee Siang (54941017900); Liew, Ah Choy (7005648285); Schamiloglu, Edl (7006390232); Rossi, Jose Osvaldo (7202397572)","54941017900; 7005648285; 7006390232; 7202397572","Oscillating Pulse Generator Based on a Nonlinear Inductive Line","2013","IEEE Transactions on Plasma Science","41","10","6516024","2619","2624","5","7","10.1109/TPS.2013.2258894","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84885954909&doi=10.1109%2fTPS.2013.2258894&partnerID=40&md5=fcdcfa662b0e0c6edb0df06ac13a1797","Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM 87131, United States; Associated Plasma Laboratory, National Institute for Space Research, São José dos Campos-SP 12227-010, Brazil","Kuek N.S., Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; Liew A.C., Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; Schamiloglu E., Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM 87131, United States; Rossi J.O., Associated Plasma Laboratory, National Institute for Space Research, São José dos Campos-SP 12227-010, Brazil","A chain of cascading LC sections consisting of series nonlinear inductors and parallel linear capacitors can be used to generate oscillating pulses. When a rectangular pulse is injected into the input of such a nonlinear inductive line (NLIL), the pulse undergoes modulation and exits at the output with oscillations in the waveform. This paper describes the implementation of high-voltage NLILs using commercial-off-the-shelf components. A pulser comprising of a storage capacitor and a fast semiconductor switch is used to provide the input pulse with approximate rectangular pulse shape. The design of the NLIL, which is a type of nonlinear lumped element transmission line (NLETL), is based on a NLETL circuit model developed earlier in-house. The nonlinear inductors made of ferrites are modeled using a simplified form of the Landau-Lifshitz-Gilbert (LLG) equation. A simple novel approach is proposed to determine the characteristic parameters in the LLG equation. Simulation results from the NLETL model are compared to the experimental results, and analyses on the voltage modulation and frequency content of the output pulses are performed. The use of crosslink capacitors in the line to modify the dispersive characteristics to enhance the performance is also investigated. With the results, the conditions and trends for producing oscillating pulses in NLILs are discussed. © 1973-2012 IEEE.","Nonlinear lumped element transmission line (NLETL); Oscillating pulses; Voltage modulation depth","Capacitors; Circuit simulation; Electric lines; Modulation; Superconducting devices; Transmission line theory; Commercial off-the-shelf components; Dispersive characteristic; Frequency contents; Landau-Lifshitz-Gilbert equations; Non-linear inductors; Nonlinear lumped element transmission lines (NLETL); Oscillating pulses; Voltage modulations; Pulse generators","","","","","","","Gaudet J., Schamiloglu E., Rossi J.O., Buchenauer C.J., Frost C., Nonlinear transmission lines for high power microwave applications-A survey, Proc. 28th IEEE Int. Power Modulators High Voltage Conf, pp. 131-138, (2008); Ikezi H., Wojtowicz S.S., Waltz J.S., Degrassie R.E., Baker D.R., High power soliton generation at microwave frequencies, J. Appl. Phys, 64, 6, pp. 3277-3281, (1988); Brown M.P., Smith P.W., High power, pulsed soliton generation at radio and microwave frequencies, Proc. 11th IEEE Int. Pulsed Power Conf, 1, pp. 346-354, (1997); Darling J.D.C., Smith P.W., High power pulse burst generation by soliton-type oscillation on nonlinear lumped element transmission lines, Proc. 17th IEEE Int. Pulsed Power Conf, pp. 119-123, (2009); Sanders J.M., Lin Y.H., Ness R., Kuthi A., Gundersen M., Pulse sharpening and soliton generation with nonlinear transmission lines for producing RF bursts, Proc. IEEE Int. Power Modulator High Voltage Conf, pp. 632-635, (2010); French D.M., Lau Y.Y., Gilgenbach R.M., High power nonlinear transmission lines with nonlinear inductance, Proc. IEEE Int. Power Modulator High Voltage Conf, pp. 598-599, (2010); Belyantsev A.M., Dubnev A.I., Klimin S.L., Kobelev Y.A., Ostrovskii L.A., Generation of radio pulses by an electromagnetic shock wave in a ferrite loaded transmission line, Tech. Phys, 40, 8, pp. 820-826, (1995); Seddon N., Spikings C.R., Dolan J.E., RF pulse formation in nonlinear transmission lines, Proc. 16th IEEE Int. Pulsed Power Conf, pp. 678-681, (2007); Rossi J.O., Rizzo P.N., Yamasaki F.S., Prospects for applications of hybrid lines in RF generation, Proc. IEEE Int. Power Modulator High Voltage Conf, pp. 632-635, (2010); Kuek N.S., Liew A.C., Schamiloglu E., Rossi J.O., Circuit modeling of nonlinear lumped element transmission lines, Proc. 18th IEEE Int. Pulsed Power Conf, pp. 185-192, (2011); Kuek N.S., Liew A.C., Schamiloglu E., Experimental demonstration of nonlinear lumped element transmission lines using COTS components, Proc. 18th IEEE Int. Pulsed Power Conf, pp. 193-198, (2011); Stohr J., Siegmann C.H., Magnetism: From Fundamentals to Nanoscale Dynamics, pp. 61-103, (2006); Gyorgy E.M., Rotational model of flux reversal in square loop ferrites, J. Appl. Phys, 28, pp. 1011-1015, (1957); Kuek N.S., Liew A.C., Schamiloglu E., Rossi J.O., Generating oscillating pulses using nonlinear capacitive transmission lines, Proc. IEEE Int. Power Modulator High Voltage Conf, pp. 2681-2685, (2012)","","","","","","","","","00933813","","ITPSB","","English","IEEE Trans Plasma Sci","Article","Final","","Scopus","2-s2.0-84885954909" +"Magni A.; Bottauscio O.; Caprile A.; Celegato F.; Ferrara E.; Fiorillo F.","Magni, Alessandro (7007060492); Bottauscio, Oriano (7006218126); Caprile, Ambra (37260980300); Celegato, Federica (16033291100); Ferrara, Enzo (56211874000); Fiorillo, Fausto (7006013405)","7007060492; 7006218126; 37260980300; 16033291100; 56211874000; 7006013405","Spin precession by pulsed inductive magnetometry in thin amorphous plates","2014","Journal of Applied Physics","115","17","17A338","","","","6","10.1063/1.4867755","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84903888631&doi=10.1063%2f1.4867755&partnerID=40&md5=b0a08ce42256e436dcec353ef384966a","Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy","Magni A., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; Bottauscio O., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; Caprile A., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; Celegato F., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; Ferrara E., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; Fiorillo F., Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy","Broadband magnetic loss and damping behavior of Co-based amorphous ribbons and thin films have been investigated. The permeability and loss response of the transverse anisotropy ribbon samples in the frequency range DC to 1 GHz is interpreted in terms of combined and distinguishable contributions to the magnetization process by domain wall displacements and magnetization rotations. The latter alone are shown to survive at the highest frequencies, where the losses are calculated via coupled Maxwell and Landau-Lifshitz-Gilbert (LLG) equations. Remarkably high values of the LLG damping coefficient α = 0.1-0.2 are invoked in this theoretical prediction. Direct measurements of α by pulsed inductive microwave magnetometry are thus performed, both in these laminae and in amorphous films of identical composition, obtaining about one order of magnitude increase of the α value upon the 100 nm÷10μm thickness range. This confirms that dissipation by eddy currents enters the LLG equation via large increase of the damping coefficient. © 2014 AIP Publishing LLC.","","Amorphous films; Damping; Eddy current testing; Magnetization; Magnetometers; Damping behaviors; Damping coefficients; Direct measurement; Domain wall displacement; Landau-Lifshitz-Gilbert equations; Magnetization rotations; Pulsed inductive microwave magnetometries; Transverse anisotropy; Maxwell equations","","","","","","","Nanocrystalline soft magnetic alloys, Handbook of Magnetic Materials, 10, (1997); Petzold J., Scr. Mater., 48, (2003); Flohrer S., Schaefer R., McCord J., Roth S., Schultz L., Fiorillo F., Gunther W., Herzer G., Acta Mater., 54, pp. 4693-4698, (2006); Magni A., Fiorillo F., Caprile A., Ferrara E., Martino L., J. Appl. Phys., 109, (2011); Magni A., Fiorillo F., Ferrara E., Caprile A., Bottauscio O., Beatrice C., IEEE Trans. Magn., 48, (2012); Magni A., Fiorillo F., Ferrara E., Caprile A., Bottauscio O., Beatrice C., IEEE Trans. Magn., 48, (2012); Ament W.S., Rado G.T., Phys. Rev., 97, (1955); Serpico C., Mayergyz I.D., Bertotti G., IEEE Trans. Magn., 37, (2001); Silva T.J., Lee C.S., Crawford T.M., Rogers C.T., J. Appl. Phys., 85, (1999); Kos A.B., Silva T.J., Kabos P., Rev. Sci. Instrum., 73, (2002); Karlqvist O., Trans. R. Inst. Tech. Stockholm, 86, (1954); Chen Y.C., Hung D.S., Yao Y.D., Lee S.F., Ji H.P., Yu C., J. Appl. Phys., 101, (2007); Scheck C., Cheng L., Bailey W.E., Appl. Phys. Lett., 88, (2006); Arias R., Mills D.L., Phys. Rev. B, 60, (1999); Hurben M.J., Patton C.E., J. Appl. Phys., 83, (1998)","A. Caprile; Istituto Nazionale di Ricerca Metrologica (INRIM), Electromagnetics Division, Torino 10135, Italy; email: a.caprile@inrim.it","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-84903888631" +"Augustine C.; Raychowdhury A.; Somasekhar D.; Tschanz J.; De V.; Roy K.","Augustine, Charles (24779266100); Raychowdhury, Arijit (6603387139); Somasekhar, Dinesh (6701705243); Tschanz, James (7004604899); De, Vivek (7005035866); Roy, Kaushik (57000621800)","24779266100; 6603387139; 6701705243; 7004604899; 7005035866; 57000621800","Design space exploration of typical STT MTJ stacks in memory arrays in the presence of variability and disturbances","2011","IEEE Transactions on Electron Devices","58","12","6062390","4333","4343","10","17","10.1109/TED.2011.2169962","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-82155166226&doi=10.1109%2fTED.2011.2169962&partnerID=40&md5=3f867c6d4e0cf8eefa22e433ea4fa102","Purdue University, West Lafayette, IN 47907-2035, United States; Circuit Research Laboratory, Intel Corporation, Hillsboro, OR 97124, United States; GlobalFoundries, Sunnyvale, CA 94085, United States","Augustine C., Purdue University, West Lafayette, IN 47907-2035, United States; Raychowdhury A., Circuit Research Laboratory, Intel Corporation, Hillsboro, OR 97124, United States; Somasekhar D., GlobalFoundries, Sunnyvale, CA 94085, United States; Tschanz J., Circuit Research Laboratory, Intel Corporation, Hillsboro, OR 97124, United States; De V., Circuit Research Laboratory, Intel Corporation, Hillsboro, OR 97124, United States; Roy K., Purdue University, West Lafayette, IN 47907-2035, United States","High leakage power in sub-100-nm memory technology nodes drives the need for nonvolatile memory devices to reduce power consumption and enhance battery life. Spin-transfer torque magnetic tunneling junction (STT-MTJ) is a promising nonvolatile memory device with comparable read and write performances as SRAM and eDRAM with almost zero standby power. In this paper, we present a simulation framework that can solve transport [using nonequilibrium Green's function (NEGF) formalism] and magnet dynamics [using Landau-Lifshitz-Gilbert (LLG) equation] self-consistently to study the read and write performances of STT-MTJ. Due to process variations, thermal disturbances, and stray fields, the performance of STT-MTJ degrades and results in one transistor-one STT-MTJ (1T-1STTMTJ) memory failures. A thorough memory design space investigation can help us to reduce such failures. Hence, we present a design space exploration framework for 1T-1STTMTJ memory, which consists of magnetic materials with different RAPA products, different genres of MTJ stacks, and a transistor. A comprehensive study based on critical memory performance metrics such as tunneling magnetoresistance, JC, and write cycle shows the relative merits and demerits of each MTJ stack for embedded memory applications. Finally, the benefits of synthetic antiferromagnet free layer in providing immunity against stray fields are shown illustrating the need for coupled free-layer stacks in scaled technology nodes. © 2011 IEEE.","Dual-barrier; dual-free-layer; failures; magnetic memory; magnetic tunneling junction (MTJ); non-equilibrium Green's function (NEGF); spin-transfer torque (STT); variability; yield","Antiferromagnetic materials; Design; Electric resistance; Failure (mechanical); Green's function; Magnetic storage; Memory architecture; Nonvolatile storage; Space research; Static random access storage; Dual-barrier; dual-free-layer; Magnetic memories; Magnetic tunneling junctions; Non-equilibrium Green's function; Spin transfer torque; variability; yield; Magnetic devices","","","","","","","Diao Z., Li Z., Wang S., Ding Y., Panchula A., Chen E., Wang L., Huai Y., Spin-transfer torque switching in magnetic tunnel junctions and spin-transfer torque random access memory, J. Phys., Condensed Matter, 19, 16, pp. 1652091-16520913, (2007); Sun J.Z., Spin angular momentum transfer in current-perpendicular nanomagnetic junctions, IBM J. Res. Develop., 50, 1, pp. 81-100, (2006); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, 1-2, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, Condens. Matter, 54, 13, pp. 9353-9358, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, Phys. Rev. Lett., 84, 14, pp. 3149-3152, (2000); Parkin S.S.P., Kaiser C., Panchula A., Rice P.M., Hughes B., Samant M., Yang S.-H., Giant tunneling magnetoresistance at room temperature with MgO (100) tunnel barriers, Nat. Mater., 3, 12, pp. 862-867, (2004); Diao Z., Panchula A., Ding Y., Pakala M., Wang S., Li Z., Apalkov D., Nagai H., Driskill-Smith A., Wang L., Chen E., Huai Y., Spin transfer switching in dual MgO magnetic tunnel junctions, Appl. Phys. Lett., 90, 13, pp. 1325081-1325083, (2007); Mojumder N.N., Augustine C., Nikonov D.E., Roy K., Electronic transport and effect of quantum confinement in dual barrier resonant tunneling spin-torque-transfer magnetic tunnel junctions, J. Appl. Phys., 108, 10, pp. 1043061-10430612, (2010); Saito Y., Sugiyama H., Inokuchi T., Inomata K., Interlayer exchange coupling dependence of thermal stability parameters in synthetic antiferromagnetic free layers, J. Appl. Phys., 99, 8, (2006); Raychowdhury A., Somasekhar D., Karnik T., De V., Design space and scalability exploration of 1T-1STT MTJ memory arrays in the presence of variability and disturbances, IEDM Tech. Dig., pp. 707-710, (2009); Chen Y., Wang Y., Wang Y., Lin C., Spin torque transfer MTJ devices with high thermal stability and low write currents, U.S. Patent 20, 90, 303, (2009); Salahuddin S., Datta D., Srivastava P., Datta S., Quantum transport simulation of tunneling based spin torque transfer (STT) devices: Design tradeoffs and torque efficiency, IEDM Tech. Dig., pp. 121-124, (2007); Datta D., Behin-Aein B., Salahuddin S., Datta S., Quantitative model for TMR and spin-transfer torque in MTJ devices, IEDM Tech. Dig., pp. 548-551, (2010); Sankey J.C., Cui Y.T., Buhrman R.A., Ralph D.C., Sun J.Z., Slonczewski J.C., Measurement of the spin-transfer-torque vector in magnetic tunnel junctions, Nat. Phys., 4, 1, pp. 67-71, (2008); Augustine C., Raychowdhury A., Somsekhar D., Tschanz J., Roy K., De V., Numerical analysis of typical STT-MTJ stacks for 1T-1R memory arrays, IEDM Tech. Dig., pp. 544-547, (2010); Brown W.F., Thermal kuctuations of a single-domain particle, Phys. Rev., 130, 5, pp. 1677-1686, (1963); Li J., Ndai P., Goel A., Salahuddin S., Roy K., Design paradigm for robust spin-torque transfer magnetic RAM (STT-MRAM) from circuit/architecture perspective, IEEE Trans. Very Large Scale Integr. (VLSI) Syst., 18, 12, pp. 1710-1723, (2010); Alvarez A.R., Abdi B.L., Young D.L., Weed H.D., Teplik J., Herald E.R., Application of statistical design and response surface methods to computer-aided VLSI device design, IEEE Trans. Comput.-Aided Design Integr. Circuits Syst., 7, 2, pp. 272-288, (1988); Lin S., Costello D.J., Error Control Coding, (2004)","","","","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-82155166226" +"Wei D.","Wei, Dan (7202909173)","7202909173","Maxwell equations and Landau–Lifshitz equations","2012","SpringerBriefs in Applied Sciences and Technology","","9783642285769","","21","52","31","0","10.1007/978-3-642-28577-6_2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85028877458&doi=10.1007%2f978-3-642-28577-6_2&partnerID=40&md5=0309df49ba92e8e8c49bb4f384fcddff","Department of Materials Science and Engineering, Tsinghua University Beijing, Shuangqing, Beijing, 100084, China","Wei D., Department of Materials Science and Engineering, Tsinghua University Beijing, Shuangqing, Beijing, 100084, China","This chapter will present the theoretical, mathematical and computational fundamentals for micromagnetics. The target of micromagnetics is to clarify the motion of magnetic moments in ferromagnetic materials and devices, which is described by the nonlinear Landau–Lifshitz equations, or the equivalent Landau–Lifshitz–Gilbert (LLG) equations. In the LLG equations, the time derivative of the magnet moment in a micromagnetic cell is controlled by the local effective magnetic field. The effective magnetic field contains the terms determined by the fundamental and applied magnetism in a magnetic material, including the external field, the crystalline anisotropy field, the exchange field, the demagnetizing field, and the magneto-elastic field. Among these field terms, the most time-consuming one in computation is the demagnetizing field, which will be calculated by the Green’s function method following the Maxwell’s equations. © 2012, The Author(s).","Demagnetizing matrix; Free energy; History of micromagnetics; Landau–Lifshitz equations; Maxwell equations; Vector analysis","Ferromagnetic materials; Free energy; Magnetic fields; Magnetic materials; Magnetic moments; Magnetism; Nonlinear equations; Nanocrystalline materials; Crystalline anisotropy; Demagnetizing field; Exchange fields; External fields; Magneto-elastic; Micromagnetics; Time derivative; Vector analysis; LLG equation; Maxwell equations","","","","","","","Landau L.D., Lifshitz E., Electrodynamics of Continuous Media, (1960); Brown W.F., La Bonte A.E., Structure and energy of one-dimensional domain walls in ferromagnetic thin films, J. Appl. Phys, 36, 4, pp. 1380-1386, (1965); Maxwell J.C., A Treatise on Electricity and Magnetism (1873), (1994); Von Laue M., Geschichte Der Physik (1950), (1978); Wei D., Wang S.M., Ding Z.J., Gao K.Z., Micromagnetics of ferromagnetic nano-devices using fast fourier transform method, IEEE Trans. Magn, 45, 8, pp. 3035-3045, (2009); Schabes M.E., Aharoni A., Magnetostatic interaction fields for a three-dimensional array of ferromagnetic cubes, IEEE Trans. Magn, 23, 6, pp. 3882-3888, (1987); Wei D., Fundamentals of Electric, Magnetic, Optic Materials and Devices (In Chinese), (2009); Landau L.D., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. Der Sow, 8, 153, (1935); Akulov N.S., Zuratomtheorie des ferromagnetismus, Z. Phys, 54, pp. 582-587, (1929); Becker R., Zurtheorie der magnetisierungskurve, Z. Phys, 62, pp. 253-269, (1930); Bloch F., Zur theorie des austauschproblems und der remanenzerscheinung der ferromag- netika, Z. Phys, 74, pp. 295-335, (1932); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, 6, pp. 3443-3449, (2004); Brown W.F., Micromagnetics, (1963); Kaya S., On the Magnetization of Single Crystals of Nickel, 17, (1928); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, IEEE Trans. Magn, 27, 4, pp. 3475-3518, (1991); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Philos. Trans. R. Soc. Lond. A, 240, (1948); Hughes G.F., Magnetization reversal in cobalt-phosphorus films, J. Appl. Phys, 54, pp. 5306-5313, (1983); Victora R.H., Micromagnetic predictions for magnetization reversal in coni films, J. Appl. Phys, 62, pp. 4220-4225, (1987); Bertram H.N., Zhu J.G., Micromagnetic studies of thin metallic films, J. Appl. Phys, 63, pp. 3248-3253, (1988); NIST Center for Information Technology Laboratory; Fredkin D.R., Koehler T.R., Numerical micromagnetics by the finite element method, IEEE Trans. Magn, 23, 5, pp. 3385-3387, (1987); Fidler J., Schrefl T., Micromagnetic modelling—the current state of the art, J. Phys. D Appl. Phys, 33, (2000); Scholz W., Fidler J., Schrefl T., Suess D., Dittrich R., Forster H., Tsiantos V., Scalable parallel micromagnetic solvers for magnetic nanostructures, Comput. Mater. Sci, 28, pp. 366-383, (2003)","D. Wei; Department of Materials Science and Engineering, Tsinghua University Beijing, Beijing, Shuangqing, 100084, China; email: weidan@tsinghua.edu.cn","","Springer Verlag","","","","","","2191530X","","","","English","SpringerBriefs Appl. Sci. Technol.","Book chapter","Final","","Scopus","2-s2.0-85028877458" +"Subash B.; Chandrasekar V.K.; Lakshmanan M.","Subash, B. (53464394500); Chandrasekar, V.K. (35795004500); Lakshmanan, M. (7006704351)","53464394500; 35795004500; 7006704351","Nonlinear dynamics of spin transfer nano-oscillators","2015","Pramana - Journal of Physics","84","3","","409","421","12","3","10.1007/s12043-014-0922-3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84924664193&doi=10.1007%2fs12043-014-0922-3&partnerID=40&md5=178985008d2fc1ffab16f018eba32d86","Centre for Nonlinear Dynamics, Department of Physics, Bharathidasan University, Tiruchirapalli, 620 024, India; Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur, 613 401, India","Subash B., Centre for Nonlinear Dynamics, Department of Physics, Bharathidasan University, Tiruchirapalli, 620 024, India; Chandrasekar V.K., Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur, 613 401, India; Lakshmanan M., Centre for Nonlinear Dynamics, Department of Physics, Bharathidasan University, Tiruchirapalli, 620 024, India","The evolution equation of a ferromagnetic spin system described by Heisenberg nearest-neighbour interaction is given by Landau-Lifshitz-Gilbert (LLG) equation, which is a fascinating nonlinear dynamical system. For a nanomagnetic trilayer structure (spin valve or pillar) an additional torque term due to spin-polarized current has been suggested by Slonczewski, which gives rise to a rich variety of dynamics in the free layer. Under appropriate conditions the spin-polarized current gives a time-varying resistance to the magnetic structure thereby inducing magnetization oscillations of frequency which lies in the microwave region. Such a device is called a spin transfer nanooscillator (STNO). However, this interesting nanoscale level source of microwaves lacks efficiency due to its low emitting power typically of the order of nWs. To overcome this difficulty, one has to consider the collective dynamics of synchronized arrays/networks of STNOs as suggested by Fert and coworkers so that the power can be enhanced N 2 times that of a single STNO. We show that this goal can be achieved by applying a common microwave magnetic field to an array of STNOs. In order to make the system technically more feasible to practical level integration with CMOS circuits, we establish suitable electrical connections between the oscillators. Although the electrical connection makes the system more complex, the applied microwave magnetic field drives the system to synchronization in large regions of parameter space. ©Indian Academy of Sciences.","Macrospin simulation; Magnetic properties of nanostructures; Synchronization","Dynamical systems; Dynamics; Electric connectors; Magnetic fields; Magnetic structure; Microwave oscillators; Microwaves; Nonlinear dynamical systems; Nonlinear equations; Spin polarization; Synchronization; Ferromagnetic spin systems; Landau-Lifshitz-Gilbert equations; Macrospin simulation; Magnetic properties of nanostructures; Microwave magnetic field; Nearest-neighbour interactions; Spin-transfer nano-oscillators; Time varying resistance; Spin dynamics","","","","","Department of Science and Technology, Ministry of Science and Technology, India, डीएसटी; Department of Atomic Energy, Government of India, पऊवि","The work forms part of a Department of Science and Technology (DST), Government of India, IRHPA project and is also supported by a DST Ramanna Fellowship of ML. He has also been financially supported by a DAE Raja Ramanna Fellowship.","Mattis D.C., Theory of Magnetism I: Statics and Dynamics, (1988); Hillebrands B., Ounadjela K., Spin Dynamics in Confined Magnetic Structures, 1-2, (2002); Landau L.D., Lifshitz L.M., Physik. Zeits. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Stiles M.D., Miltat J., Top. Appl. Phys., 101, (2006); Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Lakshmanan M., Phil. Trans. R. Soc. A, 369, (2011); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Bazaliy Y.B., Jones B.A., Zhang S.C., Phys. Rev. B, 57, (1998); Xiao J., Zangwill A., Stiles M.D., Phys. Rev. B, 72, (2005); Chung S., Mohseni S.M., Sani S.R., Iacocca E., Dumas R.K., Anh Nguyen T.N., Pogoryelov Y., Muduli P.K., Eklund A., Hoefer M., Akerman J., J. Appl. Phys., 115, (2014); Pikovsky A., Rosenblum M., Kurths J., Synchronization - A Univ Ersal Concept in Nonlinear Sciences, (2001); Kaka S., Pufall M.R., Rippard W.H., Silva T.J., Russek S.E., Katine J.A., Nature, 437, (2005); Murugesh S., Lakshmanan M., Chaos, Solitons and Fractals, 41, (2009); Murugesh S., Lakshmanan M., Chaos, 19, 1-7, (2009); Lakshmanan M., Nakumara K., Phys. Rev. Lett., 53, (1984); Yang Z., Zhang S., Li Y.C., Phys. Rev. Lett., 99, (2007); Georges B., Grollier J., Cros V., Fert A., Appl. Phys. Lett., 92, (2008); Georges B., Grollier J., Darques M., Cros V., Deranlot C., Marcilhac B., Faini G., Fert A., Phys.Rev. Lett., 101, (2008); Belanovsky A.D., Locatelli N., Skirdkov P.N., Abreu Araujo F., Zvezdin K.A., Grollier J., Cros V., Zvezdin A.K., Appl. Phys. Lett., 103, (2013); Georges B., Cros V., Fert A., Phys. Rev., 73 B, R, (2006); Tiberkevich V., Slavin A., Bankowski E., Gerhart G., Appl. Phys. Lett., 95, (2009); Li Z., Charles Li Y., Zhang S., Phys. Rev. B, 74, (2006); Nakada K., Yakata S., Kimura T., J. Appl. Phys., 111, (2012); Subash B., Chandrasekar V.K., Lakshmanan M., Europhys. Lett., 102, (2013); Urazhdin S., Tabor P., Tiberkevich V., Slavin A., Phys. Rev. Lett., 105, (2010); Subash B., Chandrasekar V.K., Lakshmanan M., Enhanced synchronization in an array of spin torque nano oscillators in the presence of oscillating external magnetic field, Europhys.Lett.; Persson J., Zhou Y., Akerman J., J. Appl. Phys., 101, (2007)","M. Lakshmanan; Centre for Nonlinear Dynamics, Department of Physics, Bharathidasan University, Tiruchirapalli, 620 024, India; email: lakshman@cnld.bdu.ac.in","","Indian Academy of Sciences","","","","","","03044289","","PRAMC","","English","Pramana J Phys","Article","Final","","Scopus","2-s2.0-84924664193" +"Taniguchi T.; Arai H.; Kubota H.; Imamura H.","Taniguchi, Tomohiro (36180180300); Arai, Hiroko (55352879400); Kubota, Hitoshi (35248482000); Imamura, Hiroshi (57386086300)","36180180300; 55352879400; 35248482000; 57386086300","Theoretical study of spin-torque oscillator with perpendicularly magnetized free layer","2014","IEEE Transactions on Magnetics","50","1","2277582","","","","14","10.1109/TMAG.2013.2277582","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84904325861&doi=10.1109%2fTMAG.2013.2277582&partnerID=40&md5=eef80b22a799e29862c9260f56f185a5","National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan","Taniguchi T., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan; Arai H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan; Kubota H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan; Imamura H., National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan","The magnetization dynamics of spin torque oscillator (STO) consisting of a perpendicularly magnetized free layer and an in-plane magnetized pinned layer was studied by solving the Landau-Lifshitz-Gilbert equation. We derived the analytical formula of the relation between the current and the oscillation frequency of the STO by analyzing the energy balance between the work done by the spin torque and the energy dissipation due to the damping. We also found that the field-like torque breaks the energy balance and changes the oscillation frequency. © 2013 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Perpendicularly magnetized free layer; Spin torque oscillator (STO); Spintronics","Energy dissipation; Magnetoelectronics; Analytical formulas; Free layers; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Oscillation frequency; Spin-torque oscillator (STO); Spin-torque oscillators; Theoretical study; Energy balance","","","","","Japan Society for the Promotion of Science London; Japan Society for the Promotion of Science, JSPS, (23226001); Japan Society for the Promotion of Science, JSPS","","Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature, 425, pp. 380-383, (2003); Rippard W.H., Pufall M.R., Kaka S., Russek S.E., Silva T.J., Phys. Rev. Lett., 92, (2004); Sankey J.C., Krivorotov I.N., Kiselev S.I., Baraganca P.M., Emley N.C., Buhrman R.A., Ralph D.C., Phys. Rev. B, 72, (2005); Krivorotov I.N., Emley N.C., Buhrman R.A., Ralph D.C., Phys. Rev. B, 77, (2008); Rippard W.H., Pufall M.R., Schneider M.L., Garello K., Russek S.E., J. Appl. Phys., 103, (2008); Sinha J., Hayashi M., Takahashi Y.K., Taniguchi T., Drapeko M., Mitani S., Hono K., Appl. Phys. Lett., 99, (2011); Nazarov A.V., Olson H.M., Cho H., Nikolaev K., Gao Z., Stokes S., Pant B.B., Appl. Phys. Lett., 88, (2006); Deac A.M., Fukushima A., Kubota H., Maehara H., Suzuki Y., Yuasa S., Nagamine Y., Tsunekawa K., Djayaprawira D.D., Watanabe N., Nat. Phys., 4, pp. 803-809, (2008); Kudo K., Nagasawa T., Sato R., Mizushima K., Appl. Phys. Lett., 95, (2009); Devolder T., Bianchini L., Kim J.V., Crozat P., Chappert C., Cornelissen S., Beeck M.O., Lagae L., J. Appl. Phys., 106, (2009); Suto H., Nagasawa T., Kudo K., Mizushima K., Sato R., Appl. Phys. Expr., 4, (2011); Matsushita K., Sato J., Imamura H., IEEE Trans. Magn., 45, 8, pp. 3422-3425, (2009); Taniguchi T., Imamura H., J. Phys. Conf. Ser., 292, (2011); Arai H., Tsukahara H., Imamura H., Appl. Phys. Lett., 101, (2012); Yakata S., Kubota H., Suzuki Y., Yakushiji K., Fukushima A., Yuasa S., Ando K., J. Appl. Phys., 105, (2009); Kubota H., Ishibashi S., Saruya T., Nozaki T., Fukushima A., Yakushiji K., Ando K., Suzuki Y., Yuasa S., J. Appl. Phys., 111, (2012); Kubota H., Proc. 12th Joint Magnetism and Magnetic Materials/International Magnetics Conf., 2013; Slonczewski J.C., Phys. Rev. B, 39, (1989); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 247, pp. 324-338, (2002); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Kent A., Ozyilmaz B., Del Barco E., Appl. Phys. Lett., 4, (2004); Lee K.J., Redon O., Dieny B., Appl. Phys. Lett., 85, (2005); Jin W., Liu Y., Chen H., IEEE. Trans. Magn., 42, (2006); Ebles U., Houssameddine D., Firastrau I., Gusakova D., Thirion C., Dieny B., B-Prejbeanu L.D., Phys. Rev. B, 78, (2008); Zwierzycki M., Tserkovnyak Y., Kelly P.J., Brataas A., Bauer G.E.W., Phys. Rev. B, 71, (2005); Xiao J., Bauer G.E.W., Phys. Rev. B, 77, (2008); Taniguchi T., Sato J., Imamura H., Phys. Rev. B, 79, (2009); Kubota H., Fukushima A., Yakushiji K., Nagahama T., Yuasa S., Ando K., Maehara H., Nagamine Y., Tsunekawa K., Djayaprawira D.D., Watanabe N., Suzuki Y., Nat. Phys., 4, pp. 37-41, (2008); Sankey J.C., Cui Y.T., Sun J.Z., Slonczewski J.C., Buhrman R.A., Ralph D.C., Nat. Phys., 4, pp. 67-71, (2008)","T. Taniguchi; National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Umezono, Tsukuba 305-8568, Japan; email: tomohiro-taniguchi@aist.go.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84904325861" +"Saravanan M.","Saravanan, M. (38562102700)","38562102700","Current-driven electromagnetic soliton collision in a ferromagnetic nanowire","2015","Physical Review E - Statistical, Nonlinear, and Soft Matter Physics","92","1","012923","","","","7","10.1103/PhysRevE.92.012923","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84938791420&doi=10.1103%2fPhysRevE.92.012923&partnerID=40&md5=41a43b7bf59f692e8c5027ff7a220dc3","Department of Physics, Saveetha School of Engineering, Saveetha University, Chennai, Tamilnadu, 602 105, India","Saravanan M., Department of Physics, Saveetha School of Engineering, Saveetha University, Chennai, Tamilnadu, 602 105, India","The propagation of an electromagnetic wave in a uniaxial ferromagnetic nanowire under the spin transfer torque effect is widely investigated in the soliton frame. The magnetization dynamics of the ferromagnetic nanowire is governed by the Landau-Lifshitz-Gilbert (LLG) equation coupled to the Maxwell equation for the electromagnetic wave propagation. A nonuniform multiscale analysis is invoked for the coupled LLG-Maxwell equations and obtains the extended derivative nonlinear Schrödinger (DNLS) equation for the magnetization and external magnetic field. The effect of electric current is explored by constructing multisoliton solutions to the extended DNLS equation and the possibility of the soliton collision is exploited using the Hirota bilinearization procedure. © 2015 American Physical Society.","","Circular waveguides; Electromagnetic wave propagation; Electromagnetic waves; Ferromagnetic materials; Ferromagnetism; Magnetization; Nanowires; Nonlinear equations; Solitons; Timing jitter; Electromagnetic solitons; External magnetic field; Ferromagnetic nanowire; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Multi scale analysis; Multi-soliton solutions; Spin transfer torque; Maxwell equations","","","","","","","Grollier J., Cros V., Hamzic A., George J.M., Jaffres H., Fert A., Faini G., Ben Youssef J., Legall H., Appl. Phys. Lett., 78, (2001); Ozyilmaz B., Kent A.D., Monsma D., Sun J.Z., Rooks M.J., Koch R.H., Phys. Rev. Lett., 91, (2003); Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Allwood D.A., Xiong G., Faulkner C.C., Atkinson D., Petit D., Cowburn R.P., Science, 309, (2005); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature (London), 425, (2003); Koch R.H., Katine J.A., Sun J.Z., Phys. Rev. Lett., 92, (2004); Tsoi M., Tsoi V., Bass J., Jansen A.G.M., Wyder P., Phys. Rev. Lett., 89, (2002); Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Tatara G., Ueda H.T., Taguchi K., Sasaki Y., Nishijima M., Takeuchi A., Phys. Rev. B, 87, (2013); Nakata I., J. Phys. Soc. Jpn., 60, (1991); Leblond H., J. Phys. A: Math. Gen., 32, (1999); Leblond H., J. Phys. A: Math. Gen., 29, (1996); Leblond H., Manna M., J. Phys. A: Math. Theor., 41, (2008); Veerakumar V., Daniel M., Phys. Rev. e, 57, (1998); Saravanan M., Phys. Lett. A, 378, (2014); Hals K.M.D., Brataas A., Phys. Rev. B, 87, (2013); He P.-B., Liu W.M., Phys. Rev. B, 72, (2005); Li Z., Zhang S., Phys. Rev. Lett., 92, (2004); Leblond H., J. Phys. A: Math. Gen., 34, (2001); Daniel M., Veerakumar V., Phys. Lett. A, 302, (2002); Kavitha L., Saravanan M., Senthilkumar V., Ravichandran R., Gopi D., J. Magn. Magn. Mater., 355, (2014); Kaup D.J., Newell A.C., J. Math. Phys., 19, (1978); Pelinovsky D.E., Yang J., Chaos, 15, (2005); Veerakumar V., Daniel M., Phys. Lett. A, 295, (2002); Hirota R., Direct Methods in Soliton Theory, (1980); Karpman V.I., Rasmussen J.J., Shagalov A.G., Phys. Rev. e, 64, (2001); Sasa N., Satsuma J., J. Phys. Soc. Jpn., 60, (1991); Yamada Y., Van Drent W.P., Abarra E.N., Suzuki T., J. Appl. Phys., 83, (1998); Glathe S., Mattheis R., Phys. Rev. B, 85, (2012); Denardo B., Galvin B., Greenfield A., Larraza A., Putterman S., Wright W., Phys. Rev. Lett., 68, (1992); Abdullaev F.H., Habibullaev P.K., Dynamics of Solitons in Non-Homogeneous Condensed Media, (1986)","","","American Physical Society","","","","","","15393755","","PLEEE","","English","Phys. Rev. E Stat. Nonlinear Soft Matter Phys.","Article","Final","","Scopus","2-s2.0-84938791420" +"Cardelli E.; Carpentieri M.; Faba A.; Finocchio G.","Cardelli, E. (57191224306); Carpentieri, M. (8590004000); Faba, A. (25027388000); Finocchio, G. (55902853000)","57191224306; 8590004000; 25027388000; 55902853000","Modeling of hysteresis in magnetic multidomains","2014","Physica B: Condensed Matter","435","","","62","65","3","19","10.1016/j.physb.2013.06.009","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84893639283&doi=10.1016%2fj.physb.2013.06.009&partnerID=40&md5=8014383ff79fc50b84a6c5a91101c5ea","Department of Industrial Engineering, University of Perugia, Perugia, Italy; Center for Electric and Magnetic Applied Research, University of Perugia, Perugia, Italy; Department of Electrotechnics and Electronics, Polytechnic of Bari, Italy; Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, Italy","Cardelli E., Department of Industrial Engineering, University of Perugia, Perugia, Italy, Center for Electric and Magnetic Applied Research, University of Perugia, Perugia, Italy; Carpentieri M., Department of Electrotechnics and Electronics, Polytechnic of Bari, Italy; Faba A., Department of Industrial Engineering, University of Perugia, Perugia, Italy, Center for Electric and Magnetic Applied Research, University of Perugia, Perugia, Italy; Finocchio G., Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, Italy","In this paper, the analysis of multi-domain nanostructures is made by means of numerical approaches. The Landau-Lifshitz-Gilbert LLG equation is used to compute the magnetic hysteresis loops for different alternate scalar polarizations. The data computed are then used to identify the parameters of a phenomenological model, based on the extension of the Preisach model in 2-D. The identification in this case is the evaluation of the size and the position of the hysterons in the H-plane. Each hysteron is associated to a domain of the nanostructure and the assembly of hysterons reproduces with satisfactory accuracy the hysteretic behavior of the nanostructure computed by the LLG equation with an extremely reduced computational time. Some possible relationships between the magnetization nanostructure and the parameters of the hysteron are suggested. These relationship should be used for a ""blind"" prediction of the magnetization state of much larger magnetic structures, whose computation using the LLG equation is not possible in practice due to the enormous computational time, supposing that magnetic structures with the same aspect ratio exhibit a similar distribution of magnetic domains. The theory is applied here to an example of Permalloy nanostructure. © 2013 Elsevier B.V.","Magnetic hysteresis; Nanomagnetic modeling; Preisach vector modeling","Aspect ratio; Magnetic domains; Magnetic hysteresis; Magnetic structure; Magnetization; Nickel alloys; Computational time; Hysteretic behavior; Landau-Lifshitz-Gilbert; Numerical approaches; Permalloy nanostructures; Phenomenological modeling; Preisach model; Vector models; Nanostructures","","","","","","","Aharoni A., Introduction to the Theory of Ferromagnetism, (1998); Della Torre E., Magnetic hysteresis, New York, (2000); Brown W.F., Micromagnetics, (1978); Lopez-Diaz L., Aurelio D., Torres L., Martinez E., Hernandez-Lopez M.A., Gomez J., Alejos O., Carpentieri M., Finocchio G., Consolo G., J. Phys. D: Appl. Phys., 45, (2012); Cardelli E., Della Torre E., Faba A., IEEE Trans. Magn., 45, 11, pp. 5192-5195, (2009); Cardelli E., IEEE Trans. Magn., 47, 8, (2011); Cardelli E., Faba A., Finocchio G., Azzerboni B., IEEE Trans. Magn., 48, 11, (2012); Cardelli E., Della Torre E., Faba A., Ovichi M., IEEE Trans. Magn., 49, 5, (2013); Cardelli E., Della Torre E., Faba A., IEEE Trans. Magn., 46, 12, (2010); Burrascano P., Cardelli E., Carpentieri M., Della Torre E., Faba A., Finocchio G., IEEE Trans. Magn., 42, 10, (2006); Giordano A., Finocchio G., Carpentieri M., Torres L., Azzerboni B., J. Appl. Phys., 111, 7, (2012); Lopez-Diaz L., Torres L., Moro E., Phys. Rev. B, 65, (2002); Torres L., Lopez-Diaz L., Martinez E., Carpentieri M., Finocchio G., J. Magn. Magn. Mater., 286, (2005); Carpentieri M., Finocchio G., Azzerboni B., Torres L., Lopez-Diaz L., Martinez E., J. Appl. Phys., 97, (2005); Carpentieri M., Finocchio G., Azzerboni B., Torres L., Martinez E., Lopez-Diaz L., Mater. Sci. Eng. B, 126, (2006)","A. Faba; Department of Industrial Engineering, University of Perugia, Perugia, Italy; email: Faba@unipg.it","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-84893639283" +"Barangi M.; Mazumder P.","Barangi, Mahmood (55585398400); Mazumder, Pinaki (35586470500)","55585398400; 35586470500","Straintronics-based magnetic tunneling junction: Dynamic and static behavior analysis and material investigation","2014","Applied Physics Letters","104","16","162403","","","","18","10.1063/1.4873128","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84900337927&doi=10.1063%2f1.4873128&partnerID=40&md5=31c941f783ccaf1a2f2d77aa95b2d98a","Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2121, United States","Barangi M., Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2121, United States; Mazumder P., Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2121, United States","We theoretically study the dynamic and static effects of mechanical stress on a straintronics device that includes a piezoelectric film combined with a magnetic tunneling junction. The inverse magnetostriction effect is studied in detail by realizing the varying magnetic susceptibility of the nanomagnet under stress. A dynamic model is developed based on the Landau-Lifshitz-Gilbert (LLG) equation, which provides a platform to simulate the magnetization vector's behavior, critical flipping voltage, and delay properties. Furthermore, by converting the LLG equation into a 2nd order damping differential equation, we develop a proximate approach. This approach predicts the dynamic behavior of the magnetization vector and its dependency on material properties and applied voltage across the device without using sophisticated numerical calculations of the LLG model. Different dynamic and static material properties are observed by simulating five common magnetostrictive materials, including a newly discovered alloy, Galfenol. © 2014 AIP Publishing LLC.","","Differential equations; Magnetic susceptibility; Signal encoding; Landau-Lifshitz-Gilbert equations; Magnetic tunneling junctions; Magnetization vector; Magnetostriction effects; Magnetostrictive material; Mechanical stress; Numerical calculation; Piezoelectric film; Stresses","","","","","Air Force Office of Scientific Research, (FA9550-12-1-0402); National Science Foundation, (ECCS-1124714)","","Borkar S., IEEE Micro, 19, (1999); Salahuddin S., Datta S., Appl. Phys. Lett., 90, (2007); Tang D.D., Wang P.K., Speriosu P.S., Le S., Kung K.K., IEEE Trans. Magn., 31, (1995); Kim J., Ryu K., Kang S.H., Jung S., IEEE Trans. VLSI, 20, (2012); Nagata T., Pure Appl. Geophys., 78, (1970); Avellaneda M., Harshe G., J. Intell. Mater. Syst. Struct., 5, (1994); Shin K.H., Inoue M., Arai K.I., IEEE Trans. Magn., 34, (1998); Ryu J., Jpn. J. Appl. Phys., Part 1, 40, (2001); Roy K., Appl. Phys. Lett., 99, (2011); Atulasimha J., Appl. Phys. Lett., 97, (2010); Sanchez F.G., (2007)","","","American Institute of Physics Inc.","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","","Scopus","2-s2.0-84900337927" +"Inami N.; Takeichi Y.; Mitsumata C.; Iwano K.; Ishikawa T.; Lee S.-J.; Yanagihara H.; Kita E.; Ono K.","Inami, Nobuhito (8713910500); Takeichi, Yasuo (56102471000); Mitsumata, Chiharu (6603204999); Iwano, Kaoru (7005547068); Ishikawa, Tadashi (57220918821); Lee, S.-J. (36457107400); Yanagihara, Hideto (7006478739); Kita, Eiji (55595405500); Ono, Kanta (7403890224)","8713910500; 56102471000; 6603204999; 7005547068; 57220918821; 36457107400; 7006478739; 55595405500; 7403890224","Three-dimensional large-scale micromagnetics simulation using fast fourier transformation","2014","IEEE Transactions on Magnetics","50","1","2278221","","","","10","10.1109/TMAG.2013.2278221","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84904281225&doi=10.1109%2fTMAG.2013.2278221&partnerID=40&md5=8a91a7346e643c6558b494e3518d796c","High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan; Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573, Japan","Inami N., High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; Takeichi Y., High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; Mitsumata C., National Institute for Materials Science (NIMS), Tsukuba 305-0047, Japan; Iwano K., High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; Ishikawa T., High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; Lee S.-J., Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573, Japan; Yanagihara H., Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573, Japan; Kita E., Institute of Applied Physics, University of Tsukuba, Tsukuba 305-8573, Japan; Ono K., High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan","We have successfully performed a large-scale micromagnetics simulation for more than 100 million cells with long-range dipolar interaction using the fast Fourier transform method. The recent demand for a coercivity mechanism in permanent magnets requires an extremely large simulation size, requiring a large-scale micromagnetics simulator. We have developed a large-scale micromagnetics simulator in which a magnetostatic energy calculation is implemented using fast Fourier transform. A hybrid parallel algorithm, which is a combination of shared-memory and distributed-memory parallel algorithms, is used to handle large data arrays. The simulation was carried out on a Hitachi SR16000/M1 supercomputer. The hybrid parallel algorithm used to perform large-scale micromagnetics simulations is discussed. © 2013 IEEE.","Fast Fourier transformation (FFT); Landau-Lifshitz-Gilbert (LLG) equation; Micromagnetics simulation; Permanent magnet (PM)","Fast Fourier transforms; Parallel algorithms; Permanent magnets; Supercomputers; Coercivity mechanisms; Fast fourier transform methods; Fast fourier transformation (FFT); Fast Fourier transformations; Landau-Lifshitz-Gilbert equations; Magnetostatic energy; Micromagnetics simulations; Permanent magnets (pm); Parallel architectures","","","","","Japan Science and Technology Agency","","Sato T., Nakatani Y., Fast micromagnetic simulation of vortex coremotion by GPU, J. Magn. Soc. Jpn., 35, pp. 163-170, (2011); Lee S.-J., Sato S., Yanagihara H., Kita E., Mitsumata C., Numerical simulation of random magnetic anisotropy with solid magnetization grains, J. Magn. Magn. Mater., 323, pp. 28-31, (2011); Sato S., Lee S.-J., Mitsumata C., Yanagihara H., Kita E., Random magnetic anisotropy in isotropic nanocrystalline composite permanent magnets, J. Appl. Phys., 109, (2011); Schrefl T., Fidler J., Numerical simulation of magnetization reversal in hard magnetic materials using a finite element method, Journal of Magnetism and Magnetic Materials, 111, 1-2, pp. 105-114, (1992); Kronmuller H., Fischer R., Hertel R., Leineweber T., Micromagnetism and the microstructure in nanocrystalline materials, J. Magn. Magn. Mater., 175, pp. 177-192, (1997); Mansuripur M., Giles R., Demagnetizing field computation for dynamic simulation of the magnetization reversal process, IEEE Trans. Magn., 24, 5, pp. 2326-2328, (1988); Giles R., Kotiuga P., Humphrey F., Three-dimensional micromagnetic simulations on the connection machine, J. Appl. Phys., 67, (1990); Fukunaga H., Yokoi Y., Nakano M., Yanai T., Numerical study of enhanced coercivity of a magnetically hard grain with thin surface layers due to antiferromagnetic coupling, IEEE Trans.Magn., 48, 7, pp. 3162-3165, (2012); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the Landau-Lifshitz-Gilbert equation for micromagnetics, Jpn. J. Appl. Phys., 28, pp. 2485-2507, (1989)","N. Inami; High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan; email: nobuhito.inami@kek.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84904281225" +"Wang J.; Peng Z.; Lee J.-F.","Wang, Jue (56023493100); Peng, Zhen (35174836600); Lee, Jin-Fa (7601472792)","56023493100; 35174836600; 7601472792","Homogenization of ferromagnetic nano-wires based metamaterials and their applications as RF components","2013","IEEE MTT-S International Microwave Symposium Digest","","","6697690","","","","0","10.1109/MWSYM.2013.6697690","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84893313027&doi=10.1109%2fMWSYM.2013.6697690&partnerID=40&md5=c3dc9d503288fde0f976a143cd5b9f7a","School of Electrical and Computer Engineering, Ohio State University, Columbus, OH 43212, United States","Wang J., School of Electrical and Computer Engineering, Ohio State University, Columbus, OH 43212, United States; Peng Z., School of Electrical and Computer Engineering, Ohio State University, Columbus, OH 43212, United States; Lee J.-F., School of Electrical and Computer Engineering, Ohio State University, Columbus, OH 43212, United States","A numerical homogenization method for extracting the equivalent electromagnetic parameters, specifically the dispersive and nonreciprocal permeability tensor, of ferromagnetic nanowire (FMNW) based metamaterials is presented herein this paper. The homogenization process takes a two-level approach. First, in the microscopic level, the susceptibility of the nanowires is calculated with the acceleration of two-dimensional fast Fourier transform (2D-FFT). Next, the macroscopic permeability tensor of the whole structure, which usually consists of millions of nanowires, is derived by solving for the Landau-Lifshitz-Gilbert (LLG) equation. With the effective material property obtained, the performance of FMNW microwave devices, such as integrated, double-band and self-biased isolators and phase shifters, will be analyzed using a full-wave simulation based on domain decomposition method (DDM), which validates the homogenization method as well as demonstrates the capabilities of the novel multiscale artificial metamaterials with RF component applications. © 2013 IEEE.","DDM; Ferromagnetic nano-wires; Homogenization; Integrated RF devices; Metamaterials; Multiscale","Domain decomposition methods; Fast Fourier transforms; Ferromagnetic materials; Ferromagnetism; Homogenization method; Metamaterials; Microwave devices; Tensors; DDM; Domain decomposition methods (DDM); Effective material property; Electromagnetic parameters; Landau-Lifshitz-Gilbert equations; Macroscopic permeability; Multiscale; RF devices; Nanowires","","","","","","","Veselago V.G., The electrodynamics of substances with simultaneously negative values of ∈and μ, Sov. Phys. Usp., (1968); Smith D.R., Padilla W., Vier D.C., Nemat-Nasser S.C., Shultz S., A composite medium with simultaneously negative permeability and permittivity, Phys. Rev. Lett., (2000); Shelby R., Smith D., Shultz S., Experimental verification of megative index of refraction, Science, (2001); Caloz C., Itoh T., Application of the transmission line theory of left-handed (LH) materials to the realization of a microstrip LH line, IEEE AP-S Int. Symp., (2002); Iyer A.K., Eleftheriades G.V., Negatuve refractive index metamaterials supporting 2-D waves, IEEE MTT-S Int. Microw. Symp. Dig., (2002); Pendry J.B., Schurig D., Smith D.R., Controlling electromagnetic fields, Science, (2006); Smith D.R., Pendry J.P., Homogenization of metamateirals by field averaging, J. Opt. Soc. Am. B, (2006); Carignan L.-P., Yelon A., Menard D., Caloz C., Ferromagnetic nanowire metamaterials: Theory and applications, IEEE Transs on Microwave Theory and Techniques, (2011); Boucher V., Carignan L.-P., Kodera T., Caloz C., Yelon A., Menard D., Effective permeability and double resonance of interacting bistable ferromagnetic nanowires, Physical Review B, 80, (2009); Ramprecht J., Sjoberg D., Biased magnetic materials in RAM applications, PIER, (2007); Peng Z., Rawat V., Lee J.-F., One way domain decomposition method with second order transmission conditions for solving electromagnetic wave problems, J. Comp. Phys., (2010); Stupfel B., A fast-domain decomposition method for the solution of electromagnetic scattering by large objects, IEEE Trans. Ant. Prop., (1996); Zhao K., Rawat V., Lee J.-F., A domain decomposition method with non-conformal meshes for finite periodic and semi-periodic structures, IEEE Trans. Ant. Prop., (2007); Li Y.-J., Jin J.-M., A new dual-primal domain decomposition approach for finite element simulation of 3-d large-scale electromagnetic problems, IEEE Trans. Ant. Prop., (2007); Carignan L.-P., Caloz C., Menard D., Dual-band integrated selfbiased edge-mode isolator based on the double ferromagnetic resonance of a bistable nanowire substrate, IEEE MTT-S International, (2010)","","","","","2013 IEEE MTT-S International Microwave Symposium Digest, MTT 2013","2 June 2013 through 7 June 2013","Seattle, WA","102388","0149645X","978-146736176-7","IMIDD","","English","IEEE MTT S Int Microwave Symp Dig","Conference paper","Final","","Scopus","2-s2.0-84893313027" +"Dan D.-V.; Malureanu S.-E.","Dan, Daniel-Vasile (53984077600); Malureanu, Simona-Emilia (53984852800)","53984077600; 53984852800","Modelling of the magnetization process based on the Landau - Lifshitz - Gilbert equation","2011","2011 7th International Symposium on Advanced Topics in Electrical Engineering, ATEE 2011","","","5952146","","","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80155133365&partnerID=40&md5=ab57eeefd98406bee8980a71e06d7641","Electrical Engineering Faculty, Numerical Modelling Laboratory, Politehnica University of Bucharest, Bucharest, Romania","Dan D.-V., Electrical Engineering Faculty, Numerical Modelling Laboratory, Politehnica University of Bucharest, Bucharest, Romania; Malureanu S.-E., Electrical Engineering Faculty, Numerical Modelling Laboratory, Politehnica University of Bucharest, Bucharest, Romania","The magnetization dynamics is described by a mathematical model that represents a time dependent nonlinear differential equation, known as the Landau Lifshitz Gilbert equation (LLG). This paper investigates several numerical methods for solving different LLG equation types. The results are compared with the analytical solution as well as with some literature versions. © 2011 Univ Politehnica of Buchare.","","Differential equations; Electrical engineering; Magnetization; Mathematical models; Numerical methods; Analytical solutions; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetization dynamics; Magnetization process; Nonlinear differential equation; Time dependent; Nonlinear equations","","","","","","","D'aquino M., Nonlinear Magnetization Dynamics in Thin - Films and Nanoparticles; Banas L., Numerical methods for the Landau - Lifshitz - Gilbert equation, Numerical Analysis and Its Application, Lecture Notes in Computer Science, 3401, 2005, pp. 158-165, (2005); Fuwa A., Ishiwata T., Tsutsumi M., Finite difference scheme for the Landau - Lifshitz equation, Journal of Computational Physics, pp. 107-113, (2006); Weinan E., Wang X., Numerical methods for the Landau - Lifshitz equation, SIAM J. Numer Anal., 38, 5, pp. 1647-1665; Mathews J.H., Fink K.K., Numerical Methods Using Matlab, (2004); Wang X.P., Cervera C.J.G., A gauss - Seidel projection method for micromagnetics simulations Landau - Lifshitz - Gilbert equation, Journal of Computational Physics, 171, pp. 357-372, (2001)","D.-V. Dan; Electrical Engineering Faculty, Numerical Modelling Laboratory, Politehnica University of Bucharest, Bucharest, Romania; email: dan@lmn.pub.ro","","","","2011 7th International Symposium on Advanced Topics in Electrical Engineering, ATEE 2011","12 May 2011 through 14 May 2011","Bucharest","87134","","978-145770507-6","","","English","Int. Symp. Adv. Top. Electr. Eng., ATEE","Conference paper","Final","","Scopus","2-s2.0-80155133365" +"Seemann K.; Leiste H.; Krüger K.","Seemann, K. (6701634406); Leiste, H. (55885138500); Krüger, K. (55805281800)","6701634406; 55885138500; 55805281800","Theoretic 3-D study of the high-frequency magnetic moment dynamics in thin ferromagnetic films with in-plane uniaxial anisotropy by considering eddy-current generation","2012","Journal of Magnetism and Magnetic Materials","324","11","","1926","1932","6","1","10.1016/j.jmmm.2012.01.042","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84857648055&doi=10.1016%2fj.jmmm.2012.01.042&partnerID=40&md5=26c62b1348261a47f8550b02e6d2447b","Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany","Seemann K., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; Leiste H., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; Krüger K., Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany","In the present paper, theoretic investigations of polarisation vector precession trajectories represented by a macro spin in ferromagnetic films with in-plane uniaxial anisotropy were realised. For this purpose, the Landau-Lifschitz-Gilbert differential equation (LLG) in combination with the Maxwell equations were solved for three dimensions by considering a linear progression of the magnetisation or polarisation with an external field. The frequency and time dependent polarisation trajectories illustrate how a magnetic moment precesses if effective damping and eddy-currents impacts its motion. For computation, typical parameter values like the saturation polarisation J s=μ 0·M s=1.4 T and in-plane uniaxial anisotropy μ 0·H u=4.5 mT were employed. The main focus of simulation was on the variation of the effective damping parameter α eff between 0.01 and 0.05 and ferromagnetic film thickness t m between 200 nm and 1200 nm. The frequency-dependent calculations were carried out between 50 MHz and 6 GHz. The time-dependent simulations were done for a duration between 5 and 30 ns. © 2012 Elsevier B.V. All rights reserved.","Ferromagnetic resonance; Ferromagnetic thin film; Landau-Lifschitz-Gilbert and Maxwell differential equations; Macro spin trajectory; Theory of ferromagnetic polarisation dynamic","Anisotropy; Critical currents; Differential equations; Electromagnetism; Ferromagnetic resonance; Magnetic moments; Maxwell equations; Polarization; Spin dynamics; Trajectories; Effective damping; External fields; Ferromagnetic films; Ferromagnetic thin films; Frequency-dependent; High frequency HF; In-plane; Linear progression; Parameter values; Thin ferromagnetic films; Three dimensions; Time dependent; Time dependent simulation; Uniaxial anisotropy; Ferromagnetic materials","","","","","Deutsche Forschungsgemeinschaft, DFG","The research activities were partially carried out within the Joint Research Project “HAUT” no. 1299 through the financial support of the Deutsche Forschungsgemeinschaft DFG and is gratefully acknowledged.","Gilbert T.L., IEEE Transactions on Magnetics, 40, (2004); Yamaguchi M., Yamada K., Kim K.H., IEEE Transactions on Magnetics, 42, (2006); Maruta K., Sugawara M., Shimada Y., Yamaguchi M., IEEE Transactions on Magnetics, 42, (2006); Sabareesan P., Daniel M., Journal of Physics: Condensed Matter, 23, (2011); Daquino M., Difratta G., Serpico C., Berotti G., Bonin R., Mayergoyz I.D., Journal of Applied Physics, 109, (2011); Mayergoyz D., Dimian M., Berotti G., Serpico C., Journal of Applied Physics, 97, (2005); Cimpoesu D., Pham H., Stancu A., Spinu L., Journal of Applied Physics, 104, (2008); Hurben M.J., Franklin D.R., Patton C.E., Journal of Applied Physics, 81, (1997); Kuanr B.K., Camley R.E., Celinski Z., Journal of Magnetism and Magnetic Materials, 286, (2005); Seemann K., Leiste H., Bekker V., Journal of Magnetism and Magnetic Materials, 278, (2004); Seemann K., Leiste H., Kovacs A., Journal of Magnetism and Magnetic Materials, 320, (2008); Seemann K., Leiste H., Klever Ch., Journal of Magnetism and Magnetic Materials, 321, (2009); Seemann K., Leiste H., Klever Ch., Journal of Magnetism and Magnetic Materials, 322, (2010)","K. Seemann; Karlsruhe Institute of Technology KIT (Campus North), Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen, Hermann-von-Helmholtz-Platz 1, Germany; email: klaus.seemann@kit.edu","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84857648055" +"Liang C.-Y.; Keller S.M.; Sepulveda A.E.; Bur A.; Sun W.-Y.; Wetzlar K.; Carman G.P.","Liang, Cheng-Yen (55957891900); Keller, Scott M. (35242642700); Sepulveda, Abdon E. (7006560707); Bur, Alexandre (36149152200); Sun, Wei-Yang (56373808500); Wetzlar, Kyle (54882210200); Carman, Gregory P. (7101801087)","55957891900; 35242642700; 7006560707; 36149152200; 56373808500; 54882210200; 7101801087","Modeling of magnetoelastic nanostructures with a fully coupled mechanical-micromagnetic model","2014","Nanotechnology","25","43","435701","","","","80","10.1088/0957-4484/25/43/435701","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84907896483&doi=10.1088%2f0957-4484%2f25%2f43%2f435701&partnerID=40&md5=6a8d274b1d07258e6dadc27dbc6b7bbb","Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States","Liang C.-Y., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Keller S.M., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Sepulveda A.E., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Bur A., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Sun W.-Y., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Wetzlar K., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Carman G.P., Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States","Micromagnetic simulations of magnetoelastic nanostructures traditionally rely on either the Stoner-Wohlfarth model or the Landau-Lifshitz-Gilbert (LLG) model, assuming uniform strain (and/or assuming uniform magnetization). While the uniform strain assumption is reasonable when modeling magnetoelastic thin films, this constant strain approach becomes increasingly inaccurate for smaller in-plane nanoscale structures. This paper presents analytical work intended to significantly improve the simulation of finite structures by fully coupling the LLG model with elastodynamics, i.e., the partial differential equations are intrinsically coupled. The coupled equations developed in this manuscript, along with the Stoner-Wohlfarth model and the LLG (constant strain) model are compared to experimental data on nickel nanostructures. The nickel nanostructures are 100 x 300 x 35 nm single domain elements that are fabricated on a Si/SiO2substrate; these nanostructures are mechanically strained when they experience an applied magnetic field, which is used to generate M vs H curves. Results reveal that this paper's fully-coupled approach corresponds the best with the experimental data on coercive field changes. This more sophisticated modeling technique is critical for guiding the design process of future nanoscale strain-mediated multiferroic elements, such as those needed in memory systems. © 2014 IOP Publishing Ltd.","Landau-Lifshitz-Gilbert (LLG) equation; micromagnetic-micromagnetic couplin; micromagnetics; simulation; single-domain nanostructures","Landau-Lifshitz-Gilbert equations; micromagnetic-micromagnetic couplin; Micromagnetics; simulation; Single domains","","","","","","","Chung J.H., Chung S.J., Lee S., Kirby B.J., Borchers J.A., Cho Y.J., Liu X., Furdyna J.K., Phys. Rev. Lett., 101, (2008); Rondinelli J.M., Stengel M., Spaldin N.A., Nat. Nanotechnol., 3, (2008); Castro I.L., Nascimento V.P., Passamani E.C., Takeuchi A.Y., Larica C., Tafur M., Pelegrini F., J. Appl. Phys., 113, (2013); Ziese M., Bern F., Vrejoiu I., J. Appl. Phys., 113, (2013); Li Z., Zhang S., Phys. Rev. B, 68, (2003); Stiles M.D., Miltat J., Top Appl. Phys., 101, (2006); Diao Z.T., Li Z.J., Wang S.Y., Ding Y.F., Panchula A., Chen E., Wang L.C., Huai Y.M., J. Phys-Condens Mat., 19, (2007); Tehrani S., Slaughter J.M., Chen E., Durlam M., Shi J., DeHerrera M., IEEE T. Magn., 35, (1999); Tehrani S., Et al., IEEE T. Magn., 36, (2000); Eerenstein W., Mathur N.D., Scott J.F., Nature, 442, (2006); Wang Y., Hu J.M., Lin Y.H., Nan C.W., NPG Asia Mater, 2, (2010); Nan C.W., Bichurin M.I., Dong S.X., Viehland D., Srinivasan G., J. Appl. Phys., 103, (2008); Ma J., Hu J.M., Li Z., Nan C.W., Adv. Mater., 23, (2011); Zhu B., Lo C.C.H., Lee S.J., Jiles D.C., J. Appl. Phys., 89, (2001); Hu R.L., Soh A.K., Zheng G.P., Ni Y., J. Magn. Magn. Mater., 301, (2006); Jia Y.M., Or S.W., Chan H.L.W., Zhao X.Y., Luo H.S., Appl. Phys. Lett., 88, (2006); Chung T.K., Keller S., Carman G.P., Appl. Phys. Lett., 94, (2009); Chung T.K., Wong K., Keller S., Wang K.L., Carman G.P., J. Appl. Phys., 106, (2009); Weiler M., Et al., New J. Phys., 11, (2009); Chen Y.J., Fitchorov T., Vittoria C., Harris V.G., Appl. Phys. Lett., 97, (2010); Brintlinger T., Et al., Nano Lett., 10, (2010); Lahtinen T.H.E., Et al., Scientific Reports, 2, (2012); Bai D.Z., Zhu J., Yu W., Bain J.A., J. Appl. Phys., 95, (2004); Zou P., Yu W., Bain J.A., IEEE T. Magn., 38, (2002); Khanna G., Clemens B.M., Zhou H., Bertram H.N., IEEE T. Magn., 37, (2001); Hu J.M., Sheng G., Zhang J.X., Nan C.W., Chen L.Q., J. Appl. Phys., 109, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Phys. Rev. B, 83, (2011); Varga E., Orlov A., Niemier M.T., Hu X.S., Bernstein G.H., Porod W., IEEE T. Nanotechnol., 9, (2010); Liu S., Hu X.S., Nahas J.J., Niemier M., Porod W., Bernstein G.H., IEEE Transactions on Nanotechnology, 10, (2011); Bur A., Wu T., Hockel J., Hsu C.J., Kim H.K.D., Chung T.K., Wong K., Wang K.L., Carman G.P., J. Appl. Phys., 109, (2011); Atulasimha J., Bandyopadhyay S., Appl. Phys. Lett., 97, (2010); Dean J., Bryan M.T., Hrkac G., Goncharov A., Freeman C.L., Bashir M.A., Schrefl T., Allwood D.A., J. Appl. Phys., 108, (2010); Chang C.M., Carman G.P., Phys. Rev. B, 76, (2007); Banas L., Lect. Notes Comput. Sc., 3401, (2005); Alouges F., Jaisson P., Math. Mod. Meth. Appl. S, 16, (2006); Cimrak I., Slodicka M., J. Comput. Appl. Math., 169, (2004); Carbou G., Efendiev M.A., Fabrie P., Math. Method Appl. Sci., 34, (2011); Shu Y.C., Lin M.P., Wu K.C., Mech. Mater., 36, (2004); Mieche C., Ethiraj G., Comput. Methods Appl. Mech. Engrg., 245-246, pp. 331-347, (2012); Zhang J.X., Chen L.Q., Acta Mater., 53, (2005); Hubert A., Ruhrig M., J. Appl. Phys., 69, (1991); Cavill S.A., Parkes D.E., Miguel J., Dhesi S.S., Edmonds K.W., Campion R.P., Rushforth A.W., Appl. Phys. Lett., 102, (2013); Stoner E.C., Wohlfarth E.P., Philos. Tr. R. Soc. S-A, 240, (1948); Gilbert T.L., IEEE T. Magn., 40, (2004); O'Handley R.C., Modern Magnetic Material: Principles and Applications, (2000); Fredkin D.R., Koehler T.R., IEEE T. Magn., 26, (1990); Szambolics H., Buda-Prejbeanu L.D., Toussaint J.C., Fruchart O., Comp. Mater. Sci., 44, (2008); Weddemann A., Kappe D., Hutten A., COMSOL Conf. (Boston, MA), (2011); COMSOL Multiphysics","","","Institute of Physics Publishing","","","","","","09574484","","NNOTE","","English","Nanotechnology","Article","Final","","Scopus","2-s2.0-84907896483" +"Wu Y.P.; Yang Y.; Yang Z.H.; Ma F.; Zong B.Y.; Ding J.","Wu, Y.P. (16030112700); Yang, Yong (56459391100); Yang, Z.H. (56962914100); Ma, Fusheng (36537646700); Zong, B.Y. (7006197179); Ding, Jun (35848560700)","16030112700; 56459391100; 56962914100; 36537646700; 7006197179; 35848560700","Tuning microwave magnetic properties of FeCoN thin films by controlling dc deposition power","2014","Journal of Applied Physics","116","9","093905","","","","8","10.1063/1.4894512","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84924530101&doi=10.1063%2f1.4894512&partnerID=40&md5=0e0a80b7626a7a76c034492936332c41","Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore; Department of Materials Science and Engineering, National University of Singapore, Singapore, 119260, Singapore","Wu Y.P., Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore; Yang Y., Department of Materials Science and Engineering, National University of Singapore, Singapore, 119260, Singapore; Yang Z.H., Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore; Ma F., Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore; Zong B.Y., Temasek Laboratories, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore; Ding J., Department of Materials Science and Engineering, National University of Singapore, Singapore, 119260, Singapore","In this work, we deposited FeCoN thin films by reactive dc magnetron sputtering under various deposition powers. Composition, microstructure, static magnetic properties, and microwave permeability of as-sputtered films were examined. The permeability spectra were theoretically analyzed based on LLG equation. When high deposition power was applied, μ 0 ′ improved significantly due to the increased Ms and decreased Hk. On the other hand, the damping coefficient λ increased with the power, which resulted in the widen permeability spectra. The physical origin of the influences should be related to the change in the film composition and microstructure, which have immediate impact on static magnetic properties and damping effect of the film. © 2014 AIP Publishing LLC.","","Cobalt compounds; Damping; Deposition; Iron compounds; Magnetic properties; Magnetism; Microstructure; Thin films; As-sputtered films; Damping coefficients; Film composition; Microwave magnetic properties; Microwave permeability; Permeability spectrum; Reactive DC magnetron sputtering; Static magnetic properties; Nitrogen compounds","","","","","","","Landau L., Lifschitz E., Phys. Z. Sowjetunion, 8, (1935); Acher O., Jacquart P.M., Fontaine J.M., Baclet P., Perrin G., IEEE Trans. Magn., 30, (1994); Jung H.S., Doyle W.D., Wittig J.E., Al-Sharab J.F., Bentley J., Appl. Phys. Lett., 81, (2002); Platt C.L., Berkowitz A.E., Smith D.J., McCartney M.R., J. Appl. Phys., 88, (2000); Shim J., Kim J., Han S.H., Kim H.J., Kim K.H., Yamaguchi M., J. Magn. Magn. Mater., 290-291, (2005); Sundar R.S., Deevi S.C., Int. Mater. Rev., 50, (2005); Chin G.Y., Wernick J.H., Ferro Magnetic Material, 2, pp. 55-188, (1980); Wu Y.P., Han G.-C., Kong L.B., J. Magn. Magn. Mater., 322, (2010); Yu J., Chang C., Karns D., Ju G., Kubota Y., Eppler W., J. Appl. Phys., 91, (2001); Minor M.K., Crawford T.M., Klemmer T.J., Pend Y., Laughlin D.E., J. Appl. Phys., 91, (2002); Gilbert T.L., Phys. Rev., 100, (1955); Kraus L., Frait Z., Schneider J., Phys. Status Solidi A, 64, (1981); Rantschler J.O., McMiael R.D., Castillo A., Shapiro A.J., Egelhoff W.F., Maranville B.B., Pulugytha D., Chen A.P., Conners L.M., J. Appl. Phys., 101, (2007); Fassbender J., McCord J., Appl. Phys. Lett., 88, (2006); McCord J., Kaltofen R., Gemming T., Huhne R., Schultz L., Phys. Rev. B, 75, (2007); Xu F., Phouc N.N., Zhang X., Ma Y., Chen X., Ong C.K., J. Appl. Phys., 104, (2008); Bekker V., Seemann K., Leiste H., J. Magn. Magn. Mater., 270, (2004); Matsunami N., Yamamura Y., Itikawa Y., Itoh N., Kazumata Y., Miyagawa S., Morita K., Shimizu R., Tawasa H., At. Data Nucl. Data Tables, 31, (1984); Babu V.H., Rajeswari J., Venkatesh S., Markandeyulu G., J. Magn. Magn. Mater., 339, (2013); Schaaf P., Prog. Mater. Sci., 47, (2002); Iwastsubo S., Naoe M., Vacuum, 66, (2002); Coey J.M.D., Smith P.A.I., J. Magn. Magn. Mater., 200, (1999); Takahashi N., Toda Y., Nakamura T., Mater. Lett., 42, (2000); Kiyotaka W., Makoto K., Hideaki A., Thin Film Materials Technology, (2003); Herzer G., Handbook of Magnetism and Advanced Magnetic Materials: Novel Materials, 4, (2007); Kittle C., J. Phys. Radium, 12, (1951); Lagarkov A.N., Rozanov K.N., Simonov N.A., Starostenko S.N., Handbook of Advanced Magnetic Materials, 4, (2005); Nakanishi K., Shimizu O., Yoshida S., IEEE Trans. J. Magn. Jpn., 8, (1993); Taffary T., Autisser D., Boust F., Pascard H., IEEE Trans. Magn., 34, (1998); Kohmoto O., J. Phys. D: Appl. Phys., 30, (1997); Acher O., Dubourg S., Phys. Rev. B, 77, (2008)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-84924530101" +"Yao Z.; Xu Q.; Wang Y.E.","Yao, Zhi (56380891100); Xu, Qiang (55369045400); Wang, Yuanxun Ethan (35194804700)","56380891100; 55369045400; 35194804700","FDTD analysis of platform effect reduction with thin film ferrite","2015","IEEE Radio and Wireless Symposium, RWS","2015-June","June","7129734","59","61","2","2","10.1109/RWS.2015.7129734","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84937905766&doi=10.1109%2fRWS.2015.7129734&partnerID=40&md5=d6ec9123600a0a53c9365ad722a3aa47","Electrical Engineering Department, University of California, Los Angeles, 90024, CA, United States","Yao Z., Electrical Engineering Department, University of California, Los Angeles, 90024, CA, United States; Xu Q., Electrical Engineering Department, University of California, Los Angeles, 90024, CA, United States; Wang Y.E., Electrical Engineering Department, University of California, Los Angeles, 90024, CA, United States","Conformal antennas suffer from the platform effect on which the radiation of the current become inefficient due to the existence of the image current in the opposite direction. The platform effect may be well shielded with thin film ferrimagnetic material that has a high in-plane permeability. A one-dimensional finite difference time domain method (1-D FDTD) is developed to model the current radiations off the thin-film ferrite coated ground plane. Both the ferromagnetic resonances (FMR) of the ferrite and the radiation of electromagnetic wave caused by the dynamic magnetic field are simulated, by solving Landau-Lifshitz-Gilbert (LLG) equation and Maxwell's equations simultaneously. The simulated relative permeability curve matches with the theoretical results. Radiated power is computed as well, which increases as the thickness of the film increases or the FMR line width of the material susceptibility decreases. © 2015 IEEE.","Electromagnetic radiation; ferrite films; ferroresonance; finite difference time domain methods; permeability","Electromagnetic waves; Ferrite; Magnetic resonance; Maxwell equations; Mechanical permeability; Thin films; Time domain analysis; Dynamic magnetic fields; Ferrite films; Ferromagnetic resonance (FMR); Ferroresonance; In-plane permeability; Landau-Lifshitz-Gilbert equations; Relative permeability curves; Thickness of the film; Finite difference time domain method","","","","","","","Sten J.C.-E., Hujanen A., Koivisto P.K., Quality factor of an electrically small antenna radiating close to a conducting plane, IEEE Trans. Antennas Propag., 49, 5, pp. 829-837, (2001); Yao Z., Wang Y., Dynamic analysis of acoustic wave mediated multiferroic radiation via FDTD methods, 2014 IEEE Int. Sym P. on Antennas and Propag., (2014); Hansen R.C., Burke M., Antennas with magnetodielectrics, Microw. Opt. Technol. Lett., 2, pp. 75-78, (2000); Mosallaei H., Sarabandi K., Magneto-dielectrics in electromagnetics: Concept and applications, IEEE Trans. Antennas Propag., 52, 6, (2004); Ikonen P.M.T., Rozanov K.N., Osipov A.V., Alitalo P., Tretyakov S.A., Magnetodielectric substrates in antenna miniaturization: Potential and limitations, IEEE Trans. Antennas Propag., 54, 11, (2006); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, J. of Comput. and Appl. Math., 176, 2, pp. 263-281, (2005); Pereda J.A., Vielva L.A., Solano M.A., Vegas A., Prieto A., FDTD analysis of magnetized ferrites: Application to the calculation of dispersion characteristics of ferriteloaded waveguides, IEEE Trans. Microw. Theory Techn., 43, 2, pp. 350-357, (1995); Pereda J.A., Vielva L.A., Solano M.A., Vegas A., Prieto A., Techniques for Land au-Lifshitz-Gilbert equation with magnetostriction, J. of Comput. and Appl. Math., 215, 2, pp. 3047-3310, (2008); Pozar D.M., Microwave Engineering, (2012)","","","IEEE Computer Society","","2015 IEEE Radio and Wireless Symposium, RWS 2015 - RWW 2015","25 January 2015 through 28 January 2015","San Diego","113047","21642958","978-147995505-3","","","English","IEEE Radio Wirel. Symp., RWS","Conference paper","Final","","Scopus","2-s2.0-84937905766" +"Xu Z.; Yang C.; Mao M.; Sutaria K.B.; Chakrabarti C.; Cao Y.","Xu, Zihan (55550223800); Yang, Chengen (44261762300); Mao, Manqing (57214502111); Sutaria, Ketul B. (55301149100); Chakrabarti, Chaitali (35554384700); Cao, Yu (35301937800)","55550223800; 44261762300; 57214502111; 55301149100; 35554384700; 35301937800","Compact modeling of STT-MTJ devices","2014","Solid-State Electronics","102","","","76","81","5","22","10.1016/j.sse.2014.06.003","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85027958877&doi=10.1016%2fj.sse.2014.06.003&partnerID=40&md5=cbcba71193ab4881b2dda12864b41f1f","School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States","Xu Z., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States; Yang C., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States; Mao M., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States; Sutaria K.B., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States; Chakrabarti C., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States; Cao Y., School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, 85287, AZ, United States","STT-MTJ is a promising device for future high-density and low-power integrated systems. To enable design exploration of STT-MTJ, this paper presents a fully compact model for efficient SPICE simulation. Derived from the fundamental LLG equation, the new model consists of RC elements that are compact equations of device geometry and material properties. They support transient SPICE simulations, providing necessary details beyond the macromodel and enable resilient memory design. The accuracy of the model is validated with numerical results and published data. Scaling analysis shows the sensitivity of STT-MTJ to its geometry. We also did variability analysis with Monte Carlo simulation of the basic 1T1MTJ memory cell to study the bit error rate performance for different transistor size and programming current profile. We show that there is a tradeoff between programming energy and cell area for the same bit error rate constraint. Finally we derive the cell size that achieves minimum energy consumption for a given bit error rate constraint (primary) and latency or area constraint (secondary). © 2014 Elsevier Ltd. All rights reserved.","Compact model; Memory; STT-MTJ","Computer simulation; Data storage equipment; Energy utilization; Intelligent systems; Monte Carlo methods; SPICE; Bit error rate (BER) performance; Compact model; Design Exploration; Integrated systems; Minimum energy consumption; Programming currents; STT-MTJ; Variability analysis; Bit error rate","","","","","National Science Foundation, NSF, (CNS-1218183)","This research is partially supported by National Science Foundation (NSF) under CNS-1218183 .","Wang X., Chen Y., Li H., Dimitrov D., Liu H., Spin torque random access memory down to 22 nm technology, Trans Magn, 44, 11, pp. 2479-2482, (2008); Sharad M., Augustine C., Panagopoulos G., Roy K., Spin-based neuron model with domain-wall magnets as synapse, Trans Nanotechnol, 11, 4, pp. 843-853, (2012); Wang P., Zhang W., Joshi R., Kanj R., Chen Y., A thermal and process variation aware MTJ switching model and its applications in soft error analysis, ICCAD, pp. 720-727, (2012); Chun K.C., Zhao J., Harms J.D., Kim T.-H., Wang J.-P., Kim C.H., A scaling roadmap and performance evaluation of in-plane and perpendicular MTJ based STT-MRAMs for high-density cache memory, JSSC, 48, 2, pp. 598-610, (2013); Ralph D.C., Stiles M.D., Current perspectives: Spin transfer torques, J MMM, 320, pp. 1190-1216, (2008); Kammerer J.-B., Madec M., Hebrard L., Compact modeling of a magnetic tunnel junction - Part I: Dynamic magnetization model, TED, 57, 6, pp. 1408-1415, (2010); Lu H.M., Zheng W.T., Jiang Q., Saturation magnetization of ferromagnetic and ferrimagnetic nanocrystals at room temperature, J Phys D: Appl Phys, 40, pp. 320-325, (2007); Faber L.-B., Zhao W., Klein J.-O., Devolder T., Chappert C., Dynamic compact model of spin-transfer torque based magnetic tunnel junction (MTJ), DTIS, pp. 130-135, (2009); Madec M., Kammerer J.-B., Hebrard L.L., Compact modeling of a magnetic tunnel junction - Part II: Tunneling current model, TED, 57, 6, pp. 1416-1424, (2010); Diao Z., Spin-transfer torque switching in magnetic tunnel junctions and spin-transfer torque random access memory, J Phys: Condens Matter, 19, 16, (2007); Lin C.J., Et al., 45 nm Low power CMOS logic compatible embedded STT MRAM utilizing a reverse-connection 1T/1MTJ cell, IEDM, pp. 1161-1164, (2009); Predictive Technology Model; Yang C., Emre Y., Xu Z., Chen H., Cao Y., Chakrabarti C., A low cost multi-tiered approach to improving the reliability of multi-level cell Pram, J Signal Process Syst, (2012)","","","Elsevier Ltd","","","","","","00381101","","SSELA","","English","Solid-State Electron.","Article","Final","","Scopus","2-s2.0-85027958877" +"Martinez J.C.; Jalil M.B.A.","Martinez, J.C. (7404312770); Jalil, M.B.A. (7006821429)","7404312770; 7006821429","Current-induced motion in a skyrmion lattice","2015","Journal of Applied Physics","117","17","17E509","","","","3","10.1063/1.4916754","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84926668141&doi=10.1063%2f1.4916754&partnerID=40&md5=870268bfc834e30b696fe2c503ecc623","Computational Nanoelectronics and Nano-device Laboratory, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore","Martinez J.C., Computational Nanoelectronics and Nano-device Laboratory, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore; Jalil M.B.A., Computational Nanoelectronics and Nano-device Laboratory, National University of Singapore, 4 Engineering Drive 3, Singapore, 117576, Singapore","For a skyrmion lattice phase of chiral magnets, we compare predictions of the Landau-Lifshitz-Gilbert (LLG) and Thiele equations for the current-induced drift velocity for a given constant spin velocity. Instead of integrating the equations over a unit cell, we only perform an angle average, while retaining information on the radial dependence of velocity within the skyrmion. Since the skyrmion-lattice dynamics draws from magnetostatic, chiral, and exchange forces, we find that different scales are involved for the m =-1 and m =-2 skyrmions, a fact that might be useful in ""tuning"" scales of the drift velocity. We note that the Thiele equation yields less information than the LLG equation and explain why the translation mode has not yet been observed. © 2015 AIP Publishing LLC.","","Crystal lattices; Chiral magnets; Drift velocities; Induced motions; Landau-Lifshitz-Gilbert; Skyrmion lattices; Spin velocity; Thiele equations; Translation modes; Velocity","","","","","","","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Parkin S.S.P., Et al., Science, 320, (2008); Jonietz F., Et al., Science, 330, (2010); Landau L.D., Et al., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Barnes S.E., Et al., Concepts in Spin Electronics, (2006); Evershor K., Et al., Phys. Rev. B, 84, (2011); Yu X.Z., Et al., Nat. Commun., 3, (2012); Evershor K., Et al., Phys. Rev. B, 86, (2012); Skyrme T., Nucl. Phys., 31, (1962); Rosler U.K., Et al., Nature, 442, (2006); Heinze S., Et al., Nat. Phys., 7, (2011); Yu X.Z., Et al., Nature, 465, (2010); Nagaosa N., Et al., Nat. Nanotechnol., 8, (2013); Rajaraman R., Solitons and Instantons, (1982); Braun H.-B., Adv. Phys., 61, (2012); Thiele A.A., Phys. Rev. Lett., 30, (1973); Huber D.L., Phys. Rev. B, 26, (1982); Iwasaki J., Et al., Nat. Commun., 4, (2013); Hubert A., Et al., Magnetic Domains, (1998); Xiao J., Et al., Phys. Rev. B, 73, (2006); Han J.H., Et al., Phys. Rev. B, 82, (2010); Oogane M., Et al., Appl. Phys. Lett., 96, (2010); Zang J., Et al., Phys. Rev. Lett., 107, (2011)","J.C. Martinez; Computational Nanoelectronics and Nano-device Laboratory, National University of Singapore, Singapore, 4 Engineering Drive 3, 117576, Singapore; email: elejcm@nus.edu.sg","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-84926668141" +"Duan Y.; Wen M.; Zhang Y.; Chen J.","Duan, Yuping (8239740400); Wen, Ming (57206263664); Zhang, Yahong (55337221800); Chen, Junlei (56183870900)","8239740400; 57206263664; 55337221800; 56183870900","Effect of temperature on the structural, magnetic, and microwave electromagnetic properties of manganese nitrides","2014","Journal of Superconductivity and Novel Magnetism","27","8","","1917","1925","8","8","10.1007/s10948-014-2527-y","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84904463330&doi=10.1007%2fs10948-014-2527-y&partnerID=40&md5=70e009434ed6e1340dfee835dc51bad1","School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China","Duan Y., School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China; Wen M., School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China; Zhang Y., School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China; Chen J., School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China","Mn doped with various loadings of nitrogen was prepared by nitridation of a micron α-Mn powder in a flowing ammonia atmosphere at a range of temperatures from 400 to 900 °C. X-ray diffraction (XRD) studies reveal that doping nitrogen content increases as the temperature rising from 400 to 600 °C and then decreases from 600 to 900 °C. A mass of ε-Mn 4N started to form during the heat treatment of α-Mn powder at 900 °C. The structural morphology and grain size of the products were carried out using scanning electron microscope (SEM). Vibration sample magnetometer (VSM) and vector network analyzer (VNA) were employed to investigate the effect of nitrogen doping on the magnetic and electromagnetic performance of the as-synthesized samples. Odd circles were found in the ε' - ε'figure, which may come from the interaction between electron charge and applied field. In addition, sphere Landau-Lifshitz-Gilbert (LLG) equation fitting approach is adopted to explain the magnetic resonance of the 900 °C sample. The composite of the 900 °C sample exhibits a wider frequency range for microwave absorption applications than other composites. The sample with a thickness of 7 mm shows two absorption peaks at about 3.6 and 14.48 GHz with the maximum reflection loss of -28.71 dB at 11.18 GHz and the absorption range below -5 dB from 2 to 18 GHz. © 2014 Springer Science+Business Media New York.","Complex permeability; Complex permittivity; Manganese nitride; Microwave absorption; Natural resonance","Electric network analyzers; Electromagnetism; Magnetic resonance; Nitrides; Nitrogen; Scanning electron microscopy; X ray diffraction; Complex permeability; Complex permittivity; Manganese nitrides; Microwave absorption; Natural resonance; Manganese","","","","","National Science and Technology 12th Five-year Support Plan of China, (2012BAJ02B04)","Acknowledgments The authors acknowledge the support from the National Science and Technology 12th Five-year Support Plan of China [No. 2012BAJ02B04].","Wang C., Han X.J., Xu P., Zhang X.L., Du Y.C., Hu S.R., Wang J.Y., Wang X.H., Appl. Phys. Lett., 98, (2011); Han M.G., Deng L.J., Appl. Phys. Lett., 90, (2007); Zhang Z.L., Ji Z.J., Duan Y.P., Gu S.C., Guo J.B., J. Mater. Sci-Mater. El., 24, (2013); Wang H., Dai Y.Y., Gong W.J., Geng D.Y., Ma S., Li D., Liu W., Zhang Z.D., Appl. Phys. Lett., 102, (2013); Jing H., Duan Y.P., Liu Z., Zhang J., Liu S.H., Phys. B, 407, (2012); Zhang J.W., Yan C., Liu S.J., Pan H.S., Gong C.H., Appl. Phys. Lett., 100, (2012); Pan H.S., Cheng X.Q., Zhang C.H., Gong C.H., Yu L.G., Appl. Phys. Lett., 102, (2013); Liu J.R., Itoh M., Jiang J.Z., Machida K., J. Magn. Magn. Mater., 277, (2004); Zuo W.L., Qiao L., Chi X., Wang T., Li F.S., J. Alloy. Compd., 509, (2011); Wu X.L., Zhong W., Jiang H.Y., Tang N.J., Zou W.Q., Du Y.W., J. Magn. Magn. Mater., 281, (2004); Bezdicka P., Klarikova A., Pasekai I., Zave K., J. Alloy. Compd., 274, (1998); Duan Y.P., Liu Z., Jing H., Zhang Y.H., Li S.Q., J. Mater. Chem. C, 22, (2012); Duan Y.P., Liu Z., Zhang Y.H., Wen M., J. Mater. Chem. C, 1, (2013); Huang H., Wang F., Lv B., Xue F.H., Guo D.Y., Park W.J., Lee W.J., Dong X.L., J. Nanosci. Nanotechnol., 12, (2012); Munekata H., Ohno H., Von Molnar S., Segmuller A., Chang L.L., Esaki L., Phys. Rev. Lett., 63, (1989); Sun Z.H., Song X.Y., Mater. Lett., 63, (2009); Feng W.J., Sun N.K., Du J., Zhang Q., Liu X.G., Deng Y.F., Zhang Z.D., Solid. State. Commun., 148, (2008); Li C.L., Yang Y., Huang H.B., Wang Z.H., Yang S.G., J. Alloys. Compd., 457, (2008); Boultif A., Louer D., J. Appl. Cryst., 37, (2004); Wang C., Han X.J., Xu P., Wang J.Y., Du Y.C., Wang X.H., Qin W., Zhang T., J. Phys. Chem., 114, (2010); Li N., Hu C.W., Cao M.H., Phys. Chem. Chem. Phys, 15, (2013); Duan Y.P., Gu S.C., Zhang Z.L., Wen M., J. Alloy. Compd., 542, (2012); Moliton A., Applied Electromagnetism and Materials, (2007); Yahiaoui R., Chung U.C., Burokur S.N., De Lustrac A., Elissalde C., Maglione M., Vigneras V., Mounaix P., Appl. Phys. A., 1, (2013); Zhang X.F., Guan P.F., Dong X.L., Appl. Phys. Lett., 97, (2010); Liao S.B., Ferromagnetic Physics, (1992); Zhang S.Y., Cao Q.X., Zhang M.L., Shi X.F., J. Appl. Phys., 113, (2013); Guan H.T., Zhao Y.B., Liu S.H., Lv S.P., Eur. Phys. J-Appl. Phys., 36, (2007)","Y. Duan; School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 Liaoning, China; email: duanyp@dlut.edu.cn","","Springer New York LLC","","","","","","15571939","","","","English","J Supercond Novel Magn","Article","Final","","Scopus","2-s2.0-84904463330" +"D'Aquino M.; Perna S.; Serpico C.; Bertotti G.; Mayergoyz I.D.","D'Aquino, M. (9732823500); Perna, S. (56439259300); Serpico, C. (23013514800); Bertotti, G. (7005370974); Mayergoyz, I.D. (35495971500)","9732823500; 56439259300; 23013514800; 7005370974; 35495971500","Analysis of reliable ultrafast precessional switching in the presence of transverse applied magnetic fields","2014","IEEE Transactions on Magnetics","50","11","7100504","","","","3","10.1109/TMAG.2014.2329325","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84915754370&doi=10.1109%2fTMAG.2014.2329325&partnerID=40&md5=57981ac72f83077a975f00afaa74da28","Department of Engineering, University of Naples Parthenope, Naples, 80143, Italy; Department of Electrical Engineering and Information Technology, University of Naples Federico II, Naples, 80125, Italy; Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Department of Electrical and Computer Engineering, University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, 20742, MD, United States","D'Aquino M., Department of Engineering, University of Naples Parthenope, Naples, 80143, Italy; Perna S., Department of Electrical Engineering and Information Technology, University of Naples Federico II, Naples, 80125, Italy; Serpico C., Department of Electrical Engineering and Information Technology, University of Naples Federico II, Naples, 80125, Italy; Bertotti G., Istituto Nazionale di Ricerca Metrologica, Turin, 10135, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland Institute for Advanced Computer Studies, University of Maryland, College Park, 20742, MD, United States","The precessional switching process of a magnetic nanoparticle subject to external field pulses applied along the hard-axis is considered. The dependence of the switching probability on the external field pulse duration is investigated. The further application of a transverse field along the intermediate anisotropy axis of the particle is used to control the quasi-random relaxation of magnetization to the reversed magnetization state. The critical field amplitudes to realize the switching are analytically determined. The robustness of the theoretical prediction is verified by macrospin numerical simulations. © 2014 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; magnetization relaxation; phase-flow dynamics; precessional switching; ultrafast magnetization dynamics","Magnetization; Nanomagnetics; Nanoparticles; Landau-Lifshitz-Gilbert equations; Magnetization relaxation; Phase flow; Precessional switching; Ultrafast magnetization dynamics; Switching","","","","","","","Wang J.-P., Magnetic data storage: Tilting for the top, Nature Mater., 4, 3, pp. 191-192, (2005); Thirion C., Wernsdorfer W., Mailly D., Switching of magnetization by nonlinear resonance studied in single nanoparticles, Nature Mater., 2, 8, pp. 524-527, (2003); Kaka S., Russek S.E., Precessional switching of submicrometer spin valves, Appl. Phys. Lett., 80, 16, pp. 2958-2960, (2002); Bertotti G., Mayergoyz I.D., Serpico C., D'Aquino M., Geometrical analysis of precessional switching and relaxation in uniformly magnetized bodies, IEEE Trans. Magn., 39, 5, pp. 2501-2503, (2003); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Switching behavior of a Stoner particle beyond the relaxation time limit, Phys. Rev. B, Condens. Matter, 61, 5, (2000); D'Aquino M., Scholz W., Schrefl T., Serpico C., Fidler J., Numerical and analytical study of fast precessional switching, J. Appl. Phys., 95, 11, pp. 7055-7057, (2004); Bertotti G., Serpico C., Mayergoyz I.D., Probabilistic aspects of magnetization relaxation in single-domain nanomagnets, Phys. Rev. Lett., 110, (2013); Serpico C., D'Aquino M., Bertotti G., Mayergoyz I.D., Analytical description of quasi-random magnetization relaxation to equilibrium, IEEE Trans. Magn., 45, 11, pp. 5224-5227, (2009)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-84915754370" +"Panagopoulos G.D.; Augustine C.; Roy K.","Panagopoulos, Georgios D. (35435654600); Augustine, Charles (24779266100); Roy, Kaushik (57000621800)","35435654600; 24779266100; 57000621800","Physics-based SPICE-compatible compact model for simulating hybrid MTJ/CMOS circuits","2013","IEEE Transactions on Electron Devices","60","9","6578571","2808","2814","6","80","10.1109/TED.2013.2275082","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84883270023&doi=10.1109%2fTED.2013.2275082&partnerID=40&md5=9fe53779fdf14b087113a2def22ebac8","Electrical Engineering Department, Purdue University, West Lafayette, IN 47907, United States","Panagopoulos G.D., Electrical Engineering Department, Purdue University, West Lafayette, IN 47907, United States; Augustine C., Electrical Engineering Department, Purdue University, West Lafayette, IN 47907, United States; Roy K., Electrical Engineering Department, Purdue University, West Lafayette, IN 47907, United States","A simulation framework that can comprehend the impact of material changes from the device level to the system level design can be of great value, especially to evaluate the impact of emerging devices on various applications. To that effect, we developed a SPICE-based hybrid magnetic tunnel junction (MTJ)/CMOS simulator, which can be used to explore new opportunities in large scale system design. In the proposed simulation framework, MTJ modeling is based on Landau-Lifshitz-Gilbert (LLG) equation incorporating both spin-torque and external magnetic field(s). LLG, along with heat diffusion equation, thermal variations, and electron transport, is implemented using SPICE-inbuilt voltage-dependent current sources and capacitors. The proposed simulation framework is flexible because the physical device parameters such as MgO thickness, ferromagnet material anisotropy (Ku), and device dimensions are user-defined parameters. Furthermore, we benchmarked this model with experiments in terms of switching current density (JC) , switching time (TSWITCH), and tunneling magnetoresistance. Finally, we used the simulation framework to study different MTJ structures, such as in-plane magnet anisotropy and perpendicular magnet anisotropy, the impact of parametric process variations and temperature on the yield of spin transfer torque magnetoresistive random access memories, magnetic flip-flops, and spin-torque oscillators. © 1963-2012 IEEE.","Compact model; hybrid design; magnetic flip-flops (MFF); magnetic tunnel junction (MTJ); simulation framework; SPICE; spin transfer torque magnetoresistive random access memory (STT-MRAM); spin-torque oscillators (STO)","Anisotropy; Flip flop circuits; Magnetic heads; Magnets; Parametric oscillators; Systems analysis; Torque; Compact model; Hybrid design; magnetic flip-flops (MFF); Magnetic tunnel junction; Simulation framework; Spin-torque oscillator (STO); STT-MRAM; SPICE","","","","","","","Wolf S.A., Lu J., Stan M.R., Chen E., Treger D.M., The promise of nanomagnetics and spintronics for future logic and universal memory, Proc. IEEE, 98, 12, pp. 2155-2168, (2010); Raychowdhury A., Somasekhar D., Karnik T., De V., Design space and scalability exploration of 1t-1stt mtj memory arrays in the presence of variability and disturbances, Proc. IEEE IEDM, pp. 1-4, (2009); Augustine C., Raychowdhury A., Somasekhar D., Tschanz J., Roy K., De V., Numerical analysis of typical stt-mtj stacks for 1t-1r memory arrays, Proc. IEEE IEDM, pp. 544-547, (2010); Augustine C., Panagopoulos G., Behin-Aein B., Srinivasan S., Sarkar A., Roy K., Low-power functionality enhanced computation architecture using spin-based devices, Proc. IEEE NANOARCH, pp. 129-136, (2011); Baibich M.N., Broto J.M., Fert A., Nguyen Van Dau F., Petroff F., Giant magnetoresistance of (001)fe/(001)cr magnetic superlattices, Phys. Rev. Lett, 61, 21, pp. 2472-2475, (1988); Sakimura N., Sugibayashi T., Nebashi R., Kasai N., Nonvolatile magnetic flip-flop for standby-power-free socs, Proc. IEEE CICC, pp. 355-358, (2008); Matsunaga S., Hayakawa J., Ikeda S., Miura K., Hasegawa H., Endoh T., Ohno H., Hanyu T., Fabrication of a nonvolatile full adder based on logic-in-memory architecture using magnetic tunnel junctions, Appl. Phys. Exp, 1, 9, pp. 0913011-0913013, (2008); Villard P., Ebels U., Houssameddine D., Katine J., Mauri D., Delaet B., Vincent P., Cyrille M., Viala B., Michel J., Prouvee J., Badets F., A ghz spintronic-based rf oscillator, IEEE J. Solid-State Circuits, 45, 1, pp. 214-223, (2010); Harms J.D., Ebrahimi F., Xiaofeng Y., Jian-Ping W., SPICE macromodel of spin-torque-transfer-operated magnetic tunnel junctions, IEEE Trans. Electron Devices, 57, 6, pp. 1425-1430, (2010); Nigam A., Munira K., Ghosh A., Wolf S., Chen E., Stan M.R., Self consistent parameterized physical mtj compact model for stt-ram, Proc. Int. Semicond. Conf, pp. 423-426, (2010); Guo W., Prenat G., Javerliac V., El Baraji M., De Mestier N., Baraduc C., Dieny B., SPICE modelling of magnetic tunnel junctions written by spin-transfer torque, J. Phys. D, Appl. Phys, 43, 21, pp. 2150011-2150018, (2010); Li J., Augustine C., Salahuddin S., Roy K., Modeling of failure probability and statistical design of spin-torque transfer magnetic random access memory (stt mram) array for yield enhancement, Proc. IEEE Design Autom. Conf, pp. 278-283, (2008); Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Phys. Rev. B, 62, 1, pp. 570-578, (2000); Brown W.F., Thermal fuctuations of a single-domain particle, Phys. Rev, 130, 5, pp. 1677-1686, (1963); Li J., Ndai P., Goel A., Salahuddin S., Roy K., Design paradigm for robust spin-torque transfer magnetic ram from (stt mram) circuit/architecture perspective, IEEE Trans. Very Large Scale Integr. (VLSI) Syst, 18, 12, pp. 1710-1723, (2010); Diao Z., Li Z., Wang S., Ding Y., Panchula A., Chen E., Wang L., Huai Y., Spin-transfer torque switching in magnetic tunnel junctions and spintransfer torque random access memory, J. Phys., Condensed Matter, 19, 16, pp. 1652091-16520913, (2007); Lee K., Kang S., Design consideration of magnetic tunnel junctions for reliable high-temperature operation of stt-mram, IEEE Trans. Magn, 46, 6, pp. 1537-1540, (2010); Salahuddin S., Datta D., Srivastava P., Datta S., Quantum transport simulation of tunneling based spin torque transfer (stt) devices: Design tradeoffs and torque efficiency, Proc. IEEE IEDM, pp. 121-124, (2007); Klselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Microwave oscillations of a nanomagnet driven by a spin-polarized current, Nature, 425, 6956, pp. 380-383, (2003); Yan L., Liou S., Wang D., Temperature dependence of magnetoresistance in magnetic tunnel junctions with different free layer structures, Phys. Rev. B, 73, 13, pp. 1344031-1344038, (2006); HSPICE Simulation and Analysis User Guide, (2006); Shang Y., Fei W., Yu H., Fast simulation of hybrid cmos and stt-mtj circuits with identified internal state variables, Proc. 17th ASP DAC, pp. 529-534, (2012); Peiyuan W., Wei Z., Joshi R., Kanj R., Yiran C., A thermal and process variation aware mtj switching model and its applications in soft error analysis, Proc. IEEE ICCAD, pp. 720-727, (2012); Faber L.-B., Weisheng Z., Klein J.-O., Devolder T., Chappert C., Dynamic compact model of spin-transfer torque based magnetic tunnel junction (mtj), Proc. 4th Int. Conf. DTIS, pp. 130-135, (2009)","","","","","","","","","00189383","","IETDA","","English","IEEE Trans. Electron Devices","Article","Final","","Scopus","2-s2.0-84883270023" +"Yoshida T.; Bai S.; Hirokawa A.; Tanabe K.; Enpuku K.","Yoshida, Takashi (55628540672); Bai, Shi (56109331200); Hirokawa, Aiki (56414781400); Tanabe, Kazuhiro (56413980700); Enpuku, Keiji (7006022081)","55628540672; 56109331200; 56414781400; 56413980700; 7006022081","Effect of viscosity on harmonic signals from magnetic fluid","2015","Journal of Magnetism and Magnetic Materials","380","","","105","110","5","45","10.1016/j.jmmm.2014.10.044","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84922513133&doi=10.1016%2fj.jmmm.2014.10.044&partnerID=40&md5=8bb75c688580d1295d788c6ee1e2faf0","Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan","Yoshida T., Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan; Bai S., Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan; Hirokawa A., Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan; Tanabe K., Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan; Enpuku K., Department of Electrical and Electronic Engineering, Kyushu University, Fukuoka, 819-0395, Japan","We explored the effect of viscosity on harmonic signals from a magnetic fluid. Using a numerical simulation that accounts for both the Brownian and Néel processes, we clarified how the magnetization mechanism is affected by viscosity. When the excitation field varies much slower than the Brownian relaxation time, magnetization can be described by the Langevin function. On the other hand, for the case when the excitation field varies much faster than the Brownian relaxation time, but much slower than the Néel relaxation time, the easy axes of the magnetic nanoparticles (MNPs) turn to some extent toward the direction of the excitation field in an equilibrium state. This alignment of the easy axes of MNPs caused by the AC field becomes more significant with the increase of the AC field strength. Consequently, the magnetization is different from the Langevin function even though Néel relaxation time is faster than time period of the external frequency. It is necessary to consider these results when we use harmonic signals from a magnetic fluid in a high-viscosity medium. © 2014 Elsevier B.V.","Brownian relaxation; Langevin equation; Magnetic fluid; Magnetic particle imaging; Néel relaxation; Stochastic LLG equation","Brownian movement; Differential equations; Excited states; Harmonic analysis; Magnetic fluids; Magnetism; Magnetization; Nanoparticles; Relaxation time; Signal analysis; Stochastic systems; Viscosity; Brownian relaxations; Equilibrium state; Langevin equation; Langevin functions; LLG equation; Magnetic nanoparti cles (MNPs); Magnetic particle imaging; Magnetization mechanism; Nanomagnetics","","","","","Japan Society for the Promotion of Science, KAKEN, (24246072, 26820159)","This work was partly supported by the Japan Society for the Promotion of Science KAKENHI Grant numbers 24246072 and 26820159 .","Pankhurst Q.A., Thanh N.T.K., Jones S.K., Dobson J., Progress in applications of magnetic nanoparticles in biomedicine, J. Phys. D: Appl. Phys. D, 42, (2009); Gleich B., Weizenecker J., Tomographic imaging using the nonlinear response of magnetic particles, Nature, 435, pp. 1214-1217, (2005); Knopp T., Biederer S., Sattel T., Weizenecker J., Gleich B., Borgert J., Buzug T.M., Three-dimensional real-time in vivo magnetic particle imaging, Phys. Med. Biol., 54, pp. 1-L10, (2009); Knopp T., Sattel T.F., Biederer S., Rahmer J., Weizenecker J., Gleich B., Borgert J., Buzug T.M., Model-based reconstruction for magnetic particle imaging, IEEE Trans. Med. Imaging, 29, pp. 12-18, (2010); Goodwill P.W., Scott G.C., Stang P.P., Conolly S.M., Narrowband magnetic particle imaging, IEEE Trans. Med. Imaging, 28, pp. 1231-1237, (2009); Goodwill P.W., Conolly S.M., The X-space formulation of the magnetic particle imaging process: 1-D signal, resolution, bandwidth, SNR, SAR, and magnetostimulation, IEEE Trans. Med. Imaging, 29, pp. 1851-1859, (2010); Goodwill P.W., Saritas E.U., Croft L.R., Kim T.N., Krishnan K.M., Schaffer D.V., Conolly S.M., X-space MPI: magnetic nanoparticles for safe medical imaging, Adv. Mater., 24, pp. 3870-3877, (2012); Biederer S., Knopp T., Sattel T.F., Ludtke-Buzug K., Gleich B., Weizenecker J., Borgert J., Buzung T.M., Magnetization response spectroscopy of superparamagnetic nanoparticles for magnetic particle imaging, J. Phys. D: Appl. Phys., 42, (2009); Ferguson R.M., Minard K.R., Krishnan K.M., Optimization of nanoparticle core size for magnetic particle imaging, J. Magn. Magn. Mater., 321, pp. 1548-1551, (2009); Ferguson R.M., Minard K.R., Khandhar A.P., Krishnan K.M., Optimizing magnetite nanoparticles for mass sensitivity in magnetic particle imaging, Med. Phys., 38, pp. 1619-1626, (2011); Yoshida T., Othman N.B., Enpuku K., Characterization of magnetically fractionated magnetic nanoparticles for magnetic particle imaging, J. Appl. Phys., 114, (2013); Yoshida T., Othman N.B., Tsubaki T., Takamiya J., Enpuku K., Evaluation of harmonic signals for the detection of magnetic nanoparticles, IEEE Trans. Magn., 48, pp. 3788-3791, (2012); Coffey W.T., Kalmykov Y.P., Waldron J.T., The Langevin Equation, (1996); Mamiya H., Jeyadevan B., Hyperthermic effects of dissipative structures of magnetic nanoparticles in large alternating magnetic fields, Sci. Rep., 1, (2011); Coffey W.T., Cregg P.J., Kalmykov Y.P., Advances in Chemical Physics, 83, (1993)","","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-84922513133" +"Rustemaj D.; Mukherjee D.","Rustemaj, Driton (55925251800); Mukherjee, Debashis (57224758323)","55925251800; 57224758323","Calculation of the energy loss in giant magnetic impedance elements using the complex magnetic permeability spectra","2013","Journal of Applied Remote Sensing","7","1","073496","","","","0","10.1117/1.JRS.7.073496","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84887425197&doi=10.1117%2f1.JRS.7.073496&partnerID=40&md5=59f88d15a73f582c260816ab698bdbf9","London South Bank University, Department of Engineering and Design, Faculty of Engineering Science and the Built Environment, London, SE1 0AA, 103 Borough Road, United Kingdom","Rustemaj D., London South Bank University, Department of Engineering and Design, Faculty of Engineering Science and the Built Environment, London, SE1 0AA, 103 Borough Road, United Kingdom; Mukherjee D., London South Bank University, Department of Engineering and Design, Faculty of Engineering Science and the Built Environment, London, SE1 0AA, 103 Borough Road, United Kingdom","Abstract. The giant magnetic impedance (GMI) effect in ferromagnetic materials has been investigated for snsing applications. The GMI properties were evaluated via numerical solution of the complex magnetic permeability of the material. MATLAB simulation was carried out to study the frequency dependence of magnetic permeability via obtaining solutions of the Landau- Lifshitz-Gilbert (LLG) and the Maxwell's equations. The results indicate that the complex magnetic permeability peaks at a frequency of 6 GHz, corresponding to the ferromagnetic resonant (FMR) frequency, where the energy loss is maximum. Avariation of the Gilbert damping parameter (?) associated with the LLG equation inversely affects this peak value. The area under the curve of complex magnetic permeability, calculated through counting the number of pixels within the image, provides an estimate of the average energy loss density within the material and appears to be consistent with the variation of the peak intensity. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE).","Damping parameter; Ferromagnetic materials; Ferromagnetic resonance; Giant magnetic impedance effect; Magnetic loss; Magnetic permeability; Sensors","Damping; Energy dissipation; Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic leakage; MATLAB; Maxwell equations; Sensors; Area under the curves; Complex magnetic permeabilities; Damping parameters; Frequency dependence; Giant magnetic impedances; Gilbert damping parameter; Landau-Lifshitz-Gilbert; Numerical solution; Magnetic permeability","","","","","","","Panina L.V., Mohri K., Magneto impedance effect in amorphous wires, Appl. Phys. Lett., 65, 9, pp. 1189-1191, (1994); Martin P., Hernando A., Applications of amorphous and nanocrystalline magnetic materials, J. Magn. Magn. Mater., 215-216, 1, pp. 729-734, (2000); Kraus L., Theory of giant magneto-impedance in the planar conductor with uniaxial magnetic anisotropy, J. Magn. Magn. Mater., 195, 3, pp. 764-768, (1999); Yelon A., Menard D., Britel M., Ciureanu P., Calculations of giant magnetoimpedance and of ferromagnetic resonance response are rigorously equivalent, Applied Physics Letters, 69, 20, pp. 3084-3085, (1996); Kittel C., Introduction to Solid State Physics, (1996); Dong C., Chen S., Hsu T.Y., A simple model of giant magneto-impedance effect in amorphous thin films, Journal of Magnetism and Magnetic Materials, 250, pp. 288-294, (2002); Landau L.D., Lifshitz E.M., Electrodynamics of Continuous Media Pergamon, (1984); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, IEEE Trans. Magn., 27, 4, pp. 3475-3517, (1991); Tanaka T., Et al., Analytical calculation for estimation of magnetic film properties for a 3-GHz thin film inductor, IEEE Trans. Magn., 40, 4, pp. 2005-2007, (2004); Mills D.L., Rezende S.M., Spin Damping in Ultrathin Magnetic Films, (2010); Iwyead A.Y., Area under A Curve Calculation, 4, (2013); Chenga J.K., Et al., Evolution of magnetic permeability and magneto-impedance effect in composite wires with insulator layer, J. Magn. Magn. Mater., 320, 6, pp. 994-998, (2008)","","","SPIE","","","","","","19313195","","JARSC","","English","J. Appl. Remote Sens.","Article","Final","","Scopus","2-s2.0-84887425197" +"Alouges F.; Kritsikis E.; Steiner J.; Toussaint J.-C.","Alouges, François (6603626324); Kritsikis, Evaggelos (25223195800); Steiner, Jutta (8715020500); Toussaint, Jean-Christophe (35502756000)","6603626324; 25223195800; 8715020500; 35502756000","A convergent and precise finite element scheme for Landau–Lifschitz–Gilbert equation","2014","Numerische Mathematik","128","3","","407","430","23","42","10.1007/s00211-014-0615-3","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84919843011&doi=10.1007%2fs00211-014-0615-3&partnerID=40&md5=be706c49801b1eb41f0e102a5ae7a76e","CMAP-École Polytechnique, Route de Saclay, Palaiseau, 91128, France; Institut Néel, 25 avenue des Martyrs, Bâtiment K, BP 166, Grenoble, 38042, France; Grenoble-INP, 46 Avenue Félix Viallet, Grenoble, 38031, France; Institute for Applied Mathematics, Mathematik Zentrum, Endenicher Allee 60, Bonn, 53115, Germany","Alouges F., CMAP-École Polytechnique, Route de Saclay, Palaiseau, 91128, France; Kritsikis E., Institut Néel, 25 avenue des Martyrs, Bâtiment K, BP 166, Grenoble, 38042, France, Grenoble-INP, 46 Avenue Félix Viallet, Grenoble, 38031, France; Steiner J., Institute for Applied Mathematics, Mathematik Zentrum, Endenicher Allee 60, Bonn, 53115, Germany; Toussaint J.-C., Institut Néel, 25 avenue des Martyrs, Bâtiment K, BP 166, Grenoble, 38042, France, Grenoble-INP, 46 Avenue Félix Viallet, Grenoble, 38031, France","In this paper, we propose a new scheme for the numerical integration of the Landau–Lifschitz–Gilbert (LLG) equations in their full complexity, in particular including stray-field interactions. The scheme is consistent up to order 2 (in time), and unconditionally stable. It combines a linear inner iteration with a non-linear renormalization stage for which a rigorous proof of convergence of the numerical solution toward a weak solution is given, when both space and time stepsizes tend to (formula presented). A numerical implementation of the scheme shows its performance on physically relevant test cases. We point out that to the knowledge of the authors this is the first finite element scheme for the LLG equations which enjoys such theoretical and practical properties. © 2014, Springer-Verlag Berlin Heidelberg.","35K55; 65M12; 65M60","","","","","","Deutsche Forschungsgemeinschaft, DFG","FA and JS both acknowledge support from the chair “Mathematical Modelling and Numerical Simulation, F-EADS-Ecole Polytechnique-INRIA-F-X” and the ANR project ANR-08-BLAN-0199. JS acknowledges support from the German Science Foundation through the Collaborative Research Center 611 “Singular Phenomena and Scaling in Mathematical Models”.","Alouges F., A new finite element scheme for Landau-Lifschitz equations, Disc. Cont. Dyn. Syst. Ser. S, 1, 2, pp. 187-196, (2008); Alouges F., A new algorithm for computing liquid crystal stable configurations: the harmonic mapping case, SIAM J. Numer. Anal., 34, 5, pp. 1708-1726, (1997); Alouges F., Kritsikis E., Toussaint J.-C., A convergent finite element approximation for the Landau–Lifschitz–Gilbert equation, Physica B, (2012); Alouges F., Conti S., DeSimone A., Pokern Y., Energetics and switching of quasi-uniform states in small ferromagnetic particles, M2AN Math. Model. Numer. Anal., 38, 2, pp. 235-248, (2004); Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau–Lifshitz equations in micromagnetism, Math. Model. Method. Appl. Sci., 16, 2, pp. 299-316, (2006); Alouges F., Soyeur A., On global weak solutions for Landau–Lifchitz equations: existence and nonuniqueness, Nonlinear analysis, theory, methods and applications 18(11), pp. 1071-1084, (1992); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal., 43, 1, pp. 220-238, (2005); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation for the Landau–Lifshitz–Gilbert equation, Math. Comp., 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau–Lifshitz–Gilbert equation, SIAM J. Numer. Anal., 44, 4, pp. 1405-1419, (2006); Brown W.F., Micromagnetics, (1963); Cimrak I., A survey on the numerics and computations for the Landau–Lifshitz equation of micromagnetism, pp. 277-309, (2007); Guslienko et al, Eigenfrequencies of vortex state excitations in magnetic submicron-size disks, J. Appl. Phys., 91, pp. 8037-8040, (2002); Hubert A., Schafer R., Magnetic domains, (1998); Kritsikis E., Toussaint J.-C., Fruchart O., Szambolics H., Buda-Prejbeanu L., Fast computations of magnetostatic fields by non-uniform fast Fourier transforms, Appl. Phys. Lett., 93, (2008); Landau L., Lifschitz I., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Zeitsch. der Sow., 8, pp. 153-169, (1935); Szambolics H., Toussaint J.-C., Buda-Prejbeanu L., Alouges F., Kritsikis E., Fruchart O., Innovative weak formulation for the LLG equation, IEEE Trans. Magn., 44, 11, pp. 3153-3156, (2008); Vanselow R., About Delaunay triangulations and discrete maximum principles for the linear conforming FEM applied to the Poisson equation, Appl. Math., 46, 1, pp. 13-28, (2001); Visintin A., On Landau–Lishitz equations for ferromagnetism, Jpn. J. Appl. Math., 2, pp. 69-84, (1985)","","","Springer Science and Business Media, LLC","","","","","","0029599X","","","","English","Numer. Math.","Article","Final","","Scopus","2-s2.0-84919843011" +"Le K.-N.; Page M.; Praetorius D.; Tran T.","Le, Kim-Ngan (55844726000); Page, Marcus (55597570300); Praetorius, Dirk (6507452481); Tran, Thanh (22836660000)","55844726000; 55597570300; 6507452481; 22836660000","On a decoupled linear FEM integrator for eddy-current-LLG","2015","Applicable Analysis","94","5","","1051","1067","16","14","10.1080/00036811.2014.916401","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84924479329&doi=10.1080%2f00036811.2014.916401&partnerID=40&md5=70bbd2b5036ed5951325b5389c8fad15","School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia; Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria","Le K.-N., School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia; Page M., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; Praetorius D., Institute for Analysis and Scientific Computing, Vienna University of Technology, Wiedner Hauptstraße 8-10, Wien, A-1040, Austria; Tran T., School of Mathematics and Statistics, The University of New South Wales, Sydney, 2052, Australia","We propose a numerical integrator for the coupled system of the eddy-current equation with the nonlinear Landau–Lifshitz–Gilbert equation. The considered effective field contains a general field contribution, and we particularly cover exchange, anisotropy, applied field and magnetic field (stemming from the eddy-current equation). Even though the considered problem is nonlinear, our scheme requires only the solution of two linear systems per time-step. Moreover, our algorithm decouples both equations so that in each time-step, one linear system is solved for the magnetization, and afterwards one linear system is solved for the magnetic field. Unconditional convergence – at least of a subsequence – towards a weak solution is proved, and our analysis even provides existence of such weak solutions. Numerical experiments with micromagnetic benchmark problems underline the performance and the stability of the proposed algorithm. © 2014, © 2014 Taylor & Francis.","convergence analysis; eddy-current equation; ferromagnetism; finite element; quasi-static Maxwell-LLG","","","","","","Australian Research Council, ARC, (DP120101886); Vienna Science and Technology Fund, WWTF, (MA09-29); Austrian Science Fund, FWF, (P21732)","The authors acknowledge financial support through the Austrian Science Fund (FWF) project P21732, the Vienna Science and Technology Fund (WWTF) project MA09-29, and the Australian Research Council (ARC) project DP120101886.","Gilbert T., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev, 100, pp. 1243-1255, (1955); Landau L., Lifschitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-168, (1935); Hubert A., Schafer R., Magnetic domains. The analysis of magnetic microstructures, Corr. 3rd printing, (1998); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: existence and nonuniqueness, Nonlinear Anal, 18, pp. 1071-1084, (1992); Visintin A., On Landau-Lifshitz equations for ferromagnetism, Japan J. Appl. Math, 2, pp. 69-84, (1985); Alouges F., A new finite element scheme for Landau-Lifshitz equations, Discrete Continuous Dyn. Syst. Ser. S, 1, pp. 187-196, (2008); Alouges F., Kritsikis E., Toussaint J., A convergent finite element approximation for Landau-Lifshitz-Gilbert equation, Phys. B, 407, pp. 1345-1349, (2012); Banas L., Bartels S., Prohl A., A convergent implicit finite element discretization of the Maxwell-Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal, 46, pp. 1399-1422, (2008); Banas L., Page M., Praetorius D., A convergent linear finite element scheme for the Maxwell-Landau-Lifshitz-Gilbert equation, (2013); Bartels S., Ko J., Prohl A., Numerical analysis of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comp, 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal, 44, pp. 1405-1419, (2006); Cimrak I., A survey on the numerics and computations for the Landau-Lifshitz equation of micromagnetism, Arch. Comput. Meth. Eng, 15, pp. 277-309, (2008); d'Aquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, J. Comput. Phys, 209, pp. 730-753, (2005); Garcia-Cervera C.J., Numerical micromagnetics: a review, Bol. Soc. Esp. Mat. Apl. SEMA, 39, pp. 103-135, (2007); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev, 48, pp. 439-483, (2006); Prohl A., Computational micromagnetism. Advances in numerical mathematics, (2001); Kim-Ngan L., Tran T., A convergent finite element approximation for the quasi-static Maxwell-Landau-Lifshitz-Gilbert equations, Comp. Math. Appl, 66, pp. 1389-1402, (2013); Bruckner F., Suess D., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Multiscale modeling in micromagnetics: well-posedness and numerical integration, Math. Models Methods Appl. Sci, (2014); Page M., On dynamical micromagnetism [PhD thesis], (2013); Monk P.B., Finite element methods for Maxwell’s equations, (2003); Brenner S., Scott L., The mathematical theory of finite element methods, (2002); Goldenits P., Konvergente numerische integration der Landau-Lifshitz-Gilbert Gleichung [Convergent numerical integration of the Landau-Lifshitz-Gilbert equation] (in German) [PhD thesis], (2012); Goldenits P., Hrkac G., Mayr M., Praetorius D., Suess D., An effective integrator for the Landau-Lifshitz-Gilbert equation, In: Proceedings of Mathmod 2012 Conference, (2012); Goldenits P., Praetorius D., Suess D., Convergent geometric integrator for the Landau-Lifshitz-Gilbert equation in micromagnetics, Proc. Appl. Math. Mech, 11, pp. 775-776, (2011); Bartels S., Stability and convergence of finite-element approximation schemes for harmonic maps, SIAM J. Numer. Anal, 43, pp. 220-238, (2005); μMag-Website of NIST-Institute","","","Taylor and Francis Ltd.","","","","","","00036811","","","","English","Appl. Anal.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84924479329" +"Martinez J.C.","Martinez, J.C. (7404312770)","7404312770","Current-induced dynamics in a skyrmion lattice","2015","2015 IEEE International Magnetics Conference, INTERMAG 2015","","","7157368","","","","0","10.1109/INTMAG.2015.7157368","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84942465655&doi=10.1109%2fINTMAG.2015.7157368&partnerID=40&md5=5967880c1c6f1e7b8c8653464bf92bb2","Department of Electrical and Computer Engineering, National University of Singapore, Singapore","Martinez J.C., Department of Electrical and Computer Engineering, National University of Singapore, Singapore","Current-induced motion of domains is an important consideration in magnetic storage design [1]. The recent observation of current-induced rotation of magnetic textures in MnSi (see Fig. 1 for a representative hexagonal skyrmion lattice) has focused interest in noncentrosymmetric ferromagnets since the current densities involved were orders of magnitude lower than those in similar magnetic materials [2]. A standard theoretical tool in dealing with such systems is the phenomenological Landau-Lifshitz-Gilbert (LLG) equation whose fundamental variable is the magnetization M(r, t) or spin in the material [3, 4]. © 2015 IEEE.","","Magnetic materials; Magnetism; Manganese compounds; Silicon compounds; Current-induced rotation; Ferromagnets; Induced motions; Landau-Lifshitz-Gilbert equations; Magnetic textures; Non-centrosymmetric; Orders of magnitude; Skyrmion lattices; Magnetic storage","","","","","","","Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Jonietz F., Et al., Science, 330, (2010); Evershor K., Et al., Phys. Rev. B., 86, (2012); Thiele A.A., Phys. Rev. Lett., 30, (1972); Nagaosa N., Tokura Y., Nature Nanotech., 8, (2013); Petrova O., Tchernyshyov O., Phys. Rev. B., 84, (2011); Zang J., Mostovoy M., Han J.H., Nagaosa N., Phys. Rev. Lett., 13, (2011)","","","Institute of Electrical and Electronics Engineers Inc.","","2015 IEEE International Magnetics Conference, INTERMAG 2015","11 May 2015 through 15 May 2015","Beijing","113931","","978-147997322-4","","","English","IEEE Int. Magn. Conf., INTERMAG","Conference paper","Final","","Scopus","2-s2.0-84942465655" +"Bruckner F.; Vogler C.; Bergmair B.; Huber T.; Fuger M.; Suess D.; Feischl M.; Fuehrer T.; Page M.; Praetorius D.","Bruckner, Florian (44561022400); Vogler, Christoph (42762642500); Bergmair, Bernhard (42760985600); Huber, Thomas (57191289738); Fuger, Markus (35725437900); Suess, Dieter (7004076065); Feischl, Michael (52363525000); Fuehrer, Thomas (57199350020); Page, Marcus (55597570300); Praetorius, Dirk (6507452481)","44561022400; 42762642500; 42760985600; 57191289738; 35725437900; 7004076065; 52363525000; 57199350020; 55597570300; 6507452481","Combining micromagnetism and magnetostatic Maxwell equations for multiscale magnetic simulations","2013","Journal of Magnetism and Magnetic Materials","343","","","163","168","5","17","10.1016/j.jmmm.2013.04.085","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84885138187&doi=10.1016%2fj.jmmm.2013.04.085&partnerID=40&md5=07e7ee7c6cc9cde2b6cfec91fe35c8a6","Vienna University of Technology, Institute of Solid State Physics, Austria; Vienna University of Technology, Institute for Analysis and Scientific Computing, Austria","Bruckner F., Vienna University of Technology, Institute of Solid State Physics, Austria; Vogler C., Vienna University of Technology, Institute of Solid State Physics, Austria; Bergmair B., Vienna University of Technology, Institute of Solid State Physics, Austria; Huber T., Vienna University of Technology, Institute of Solid State Physics, Austria; Fuger M., Vienna University of Technology, Institute of Solid State Physics, Austria; Suess D., Vienna University of Technology, Institute of Solid State Physics, Austria; Feischl M., Vienna University of Technology, Institute for Analysis and Scientific Computing, Austria; Fuehrer T., Vienna University of Technology, Institute for Analysis and Scientific Computing, Austria; Page M., Vienna University of Technology, Institute for Analysis and Scientific Computing, Austria; Praetorius D., Vienna University of Technology, Institute for Analysis and Scientific Computing, Austria","Magnetostatic Maxwell equations and the Landau-Lifshitz-Gilbert (LLG) equation are combined to a multiscale method, which allows to extend the problem size of traditional micromagnetic simulations. By means of magnetostatic Maxwell equations macroscopic regions can be handled in an averaged and stationary sense, whereas the LLG allows to accurately describe domain formation as well as magnetization dynamics in some microscopic subregions. The two regions are coupled by means of their strayfield and the combined system is solved by an optimized time integration scheme. © 2013 CERN. The Authors. Published by Elsevier B.V. All rights reserved.","LLG; Magnetostatic Maxwell equation; Micromagnetism; Multiscale; Time integration","Magnetostatics; Landau-Lifshitz-Gilbert equations; Macroscopic regions; Magnetization dynamics; Micro magnetisms; Micromagnetic simulations; Multiscale; Time integration; Time-integration scheme; Maxwell equations","","","","","Austrian Science Fund, FWF, (F4112-N13)","The authors would like to thank the projects WWTF:MA09-029 and Austrian Science Fund (FWF):F4112-N13 for the financial support.","Vansteenkiste A., Van De Wiele B., MuMax: A New High-performance Micro-magnetic Simulation Tool; Li S., Livshitz B., Lomakin V., Graphics processing unit accelerated O (N) micromagnetic solver, IEEE Transactions on Magnetics, 46, pp. 2373-2375, (2010); Suess D., Tsiantos V., Schrefl T., Fidler J., Scholz W., Forster H., Dittrich R., Miles J.J., Time resolved micromagnetics using a preconditioned time integration method, Journal of Magnetism and Magnetic Materials, 248, 2, pp. 298-311, (2002); D'Aquino M., Serpico C., Miano G., Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule, Journal of Computational Physics, 209, 2, pp. 730-753, (2005); Slodiiika M., Banas L., A numerical scheme for a maxwell-landau-lifshitz-gilbert system, Applied Mathematics and Computation, 158, pp. 79-99, (2004); Wang X.-P., Garcia-Cervera C.J., Weinan E., A gauss-seidel projection method for micromagnetics simulations, Journal of Computational Physics, 171, 1, pp. 357-372, (2001); Alouges F., Kritsikis E., Toussaint J., A convergent finite element approximation for landau-lifshitz-gilbert equation, Physica B, 407, pp. 1345-1349, (2012); Goldenits P., Hrkac G., Praetorius D., Suess D., An effective integrator for the landau-lifshitz-gilbert equation, Proceedings of Mathmod 2012 Conference; Abert C., Selke G., Kruger B., Drews A., A fast finite-difference method for micromagnetics using the magnetic scalar potential, IEEE Transactions on Magnetics, 48, pp. 1105-1109, (2012); Kanai Y., Saiki M., Hirasawa K., Tsukamomo T., Yoshida K., Landau-Lifshitz-Gilbert micromagnetic analysis of single-pole-type write head for perpendicular magnetic recording using full-FFT program on PC cluster system, IEEE Transactions on Magnetics, 44, 6, pp. 1602-1605, (2008); Beatson R.K., Greengard L., A short course on fast multipole methods, Wavelets, Multilevel Methods and Elliptic PDEs, pp. 1-37, (1997); Blue J., Scheinfein M., Using multipoles decreases computation time for magnetostatic self-energy, IEEE Transactions on Magnetics, 27, pp. 4778-4780, (1991); Livshitz B., Boag A., Bertram N., Lomakin V., Nonuniform grid algorithm for fast calculation of magnetostatic interactions in micromagnetics, Journal of Applied Physics, 105, (2009); Fredkin D.R., Koehler T.R., Hybrid method for computing demagnetizing fields, IEEE Transactions on Magnetics, 26, 2, pp. 415-417, (1990); Knittel A., Franchin M., Bordignon G., Fischbacher T., Bending S., Fangohr H., Compression of boundary element matrix in micromagnetic simulations, Journal of Applied Physics, 105, (2009); Popovic N., Praetorius D., Applications of H-matrix techniques in micromagnetics, Computing, 74, pp. 177-204, (2005); Exl L., Auzinger W., Bance S., Gusenbauer M., Reichel F., Schrefl T., Fast stray field computation on tensor grids, Journal of Computational Physics, 231, pp. 2840-2850, (2012); Goncharov A., Hrkac G., Dean J., Schrefl T., Kronecker product approximation of demagnetizing tensors for micromagnetics, Journal of Computational Physics, 229, pp. 2544-2549, (2010); Aziz M., Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method, Progress in Electromagnetic Research B, 15, pp. 1-29, (2009); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, Journal of Computational and Applied Mathematics, 176, 2, pp. 263-281, (2005); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Applied Numerical Mathematics, 46, 1, pp. 95-111, (2003); Bruckner F., Vogler C., Feischl M., Praetorius D., Bergmair B., Huber T., Fuger M., Suess D., 3D FEM-BEM-coupling method to solve magnetostatic maxwell equations, Journal of Magnetism and Magnetic Materials, 324, pp. 1862-1866, (2012); Petzold L.R., Differential/algebraic equations are not ODEs, SIAM Journal on Scientific Computing, 3, pp. 367-384, (1982); Hindmarsh A., Brown P., Grant K., Lee S., Serban R., Shumaker D., Woodward C., SUNDIALS: Suite of nonlinear and differential/algebraic equation solvers, ACM Transactions on Mathematical Software, 31, pp. 363-396, (2005); Bruckner F., Feischl M., Fuhrer T., Goldenits P., Page M., Praetorius D., Suess D., Multiscale Modeling in Micromagnetics: Well-posedness and Numerical Integration, (2012); She S., Wei D., Zheng Y., Qu B., Ren T., Liu X., Wei F., Micromagnetic simulation of transfer curve in giant-magnetoresistive head, Chinese Phys. Lett., 26","F. Bruckner; Vienna University of Technology, Institute of Solid State Physics, Austria; email: e0425375@gmail.com","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Green Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-84885138187" +"Keller S.M.; Liang C.-Y.; Sepulveda A.; Carman G.P.","Keller, Scott M. (35242642700); Liang, Cheng-Yen (55957891900); Sepulveda, Abdon (7006560707); Carman, Gregory P. (7101801087)","35242642700; 55957891900; 7006560707; 7101801087","Voltage control of single magnetic domain nanoscale multiferroic heterostructure","2015","2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015","","","7181043","796","798","2","1","10.1109/TRANSDUCERS.2015.7181043","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84955448521&doi=10.1109%2fTRANSDUCERS.2015.7181043&partnerID=40&md5=0bbb053a4759f8fa115ca053e9ab1871","Translational Applications of Nanoscale Multiferroic Systems TANMS, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States","Keller S.M., Translational Applications of Nanoscale Multiferroic Systems TANMS, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Liang C.-Y., Translational Applications of Nanoscale Multiferroic Systems TANMS, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Sepulveda A., Translational Applications of Nanoscale Multiferroic Systems TANMS, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States; Carman G.P., Translational Applications of Nanoscale Multiferroic Systems TANMS, Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 90095, CA, United States","Micromagnetic simulations of magnetoelastic nanostructures traditionally rely on either the Stoner-Wohlfarth model or the Landau-Lifshitz-Gilbert LLG model assuming uniform strain (and/or assuming uniform magnetization). While the uniform strain assumption is reasonable when modeling magnetoelastic thin films, this constant strain approach becomes increasingly inaccurate for smaller in-plane nanoscale structures. This paper presents analytical work verified with experimental data to significantly improve simulation of finite structures by fully coupling LLG with elastodynamics, i.e. the partial differential equations are intrinsically coupled. Analytical predictions for reorienting a single domain element is also described. © 2015 IEEE.","","Actuators; Magnetic domains; Microsystems; Nanomagnetics; Nanotechnology; Transducers; Analytical predictions; Landau-Lifshitz-Gilbert; Micromagnetic simulations; Multiferroic heterostructure; Nanoscale structure; Single magnetic domains; Single-domain elements; Stoner-Wohlfarth model; Solid-state sensors","","","","","","","Ma J., Hu J.M., Li Z., Nan C.W., Recent progress in multiferroic magnetoelectric composites: From bulk to thin films, Advanced Materials, 23, pp. 1062-1087, (2011); Zhu B., Lo C.C.H., Lee S.J., Jiles D.C., Micromagnetic modeling of the effects of stress on magnetic properties, Journal of Applied Physics, 89, pp. 7009-7011, (2001); Weiler M., Brandlmaier A., Geprags S., Althammer M., Opel M., Bihler C., Huebl H., Brandt M.S., Voltage controlled inversion of magnetic anisotropy in a ferromagnetic thin film at room temperature, New J Phys, 11, (2009); Hu R.L., Soh A.K., Zheng G.P., Ni Y., Micromagnetic modeling studies on the effects of stress on magnetization reversal and dynamic hysteresis, Journal of Magnetism and Magnetic Materials, 301, pp. 458-468, (2006); Chen Y.J., Fitchorov T., Vittoria C., Harris V.G., Electrically controlled magnetization switching in a multiferroic heterostructure, Applied Physics Letters, 97, (2010); Hu J.M., Sheng G., Zhang J.X., Nan C.W., Chen L.Q., Phase-field simulation of electric-fieldinduced in-plane magnetic domain switching in magnetic/ferroelectric layered heterostructures, Journal of Applied Physics, 109, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Switching dynamics of a magnetostrictive single-domain nanomagnet subjected to stress, Physical Review B, 83, (2011); Bur A., Wu T., Hockel J., Hsu C.J., Kim H.K.D., Chung T.K., Wong K., Wang K.L., Carman G.P., Strain-induced magnetization change in patterned ferromagnetic nickel nanostructures, Journal of Applied Physics, 109, (2011); Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using multiferroic single-domain nanomagnets, Applied Physics Letters, 97, (2010); Banas L., Numerical methods for the Landau-Lifshitz-Gilbert equation, Numerical Analysis and Its Applications, 3401, pp. 158-165, (2005); Shu Y.C., Lin M.P., Wu K.C., Micromagnetic modeling of magnetostrictive materials under intrinsic stress, Mechanics of Materials, 36, pp. 975-997, (2004); Zhang J.X., Chen L.Q., Phase-field microelasticity theory and micromagnetic simulations of domain structures in giant magnetostrictive materials, Acta Materialia, 53, pp. 2845-2855, (2005); Robert C., O'Handley, Modern Magnetic Material: Principles and Applications, (2000)","","","Institute of Electrical and Electronics Engineers Inc.","Transducer Research Foundation (TRF)","18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015","21 June 2015 through 25 June 2015","Anchorage","116744","","978-147998955-3","","","English","Transducers - Int. Conf. Solid-State Sensors, Actuators Microsyst, TRANSDUCERS","Conference paper","Final","","Scopus","2-s2.0-84955448521" +"Chen J.; Jalil M.B.A.; Tan S.G.","Chen, Ji (56687961100); Jalil, Mansoor Bin Abdul (7006821429); Tan, Seng Ghee (8571745900)","56687961100; 7006821429; 8571745900","Spin torque on the surface of graphene in the presence of spin orbit splitting","2013","AIP Advances","3","6","062127","","","","7","10.1063/1.4812696","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84882755526&doi=10.1063%2f1.4812696&partnerID=40&md5=bc5cb3f5806dfb45cf104b70ff8b5331","Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Data Storage Institute, A STAR (Agency for Science, Technology and Research), DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore","Chen J., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore, Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Tan S.G., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore, Data Storage Institute, A STAR (Agency for Science, Technology and Research), DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore","We study theoretically the spin transfer torque of a ferromagnetic layer coupled to (deposited onto) a graphene surface in the presence of the Rashba spin orbit coupling (RSOC). We show that the RSOC induces an effective magnetic field, which will result in the spin precession of conduction electrons.We derive correspondingly the generalized Landau-Lifshitz-Gilbert (LLG) equation, which describes the precessional motion of local magnetization under the influence of the spin orbit effect. Our theoretical estimate indicates that the spin orbit spin torque may have significant effect on the magnetization dynamics of the ferromagnetic layer coupled to the graphene surface. © 2013 Author(s).","","Ferromagnetic materials; Ferromagnetism; Graphene; Magnetization; Spin orbit coupling; Ferromagnetic layers; Landau-Lifshitz-Gilbert equations; Local magnetization; Magnetization dynamics; Rashba spin-orbit coupling; Spin transfer torque; Spin-orbit effects; Spin-orbit splittings; Spin dynamics","","","","","ASTAR SERC, (092 101 0060, R-398-000-061-331)","We gratefully acknowledge financial support of the ASTAR SERC Grant No. 092 101 0060 (R-398-000-061-331).","Das Sarma S., Adam S., Hwang E.H., Rossi E., Rev. Mod. Phys., 83, (2011); Tombros N., Jozsa C., Popinciuc M., Jonkman H.T., Wees B.J.V., Nature, 448, (2007); Kane C.L., Mele E.J., Phys. Rev. Lett., 95, (2005); Kane C.L., Mele E.J., Phys. Rev. Lett., 95, (2005); Dedkov Yu.S., Fonin M., Rudiger U., Laubschat C., Phys. Rev. Lett, 100, (2008); Varykhalov A., Sanchez-Barriga J., Shikin A.M., Biswas C., Vescovo E., Rybkin A., Marchenoko D., Rader O., Phys. Rev. Lett, 101, (2008); Slonczewski J., J.Magn.Magn.Mater, 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Obata K., Tatara G., Phys. Rev. B, 77, (2008); Manchon A., Zhang S., Phys. Rev. B, 78, (2008); Tan S.G., Jalil M.B.A., Fujita T., Liu X.J., Ann. Phys. (NY), 326, (2011); Yokoyama T., Phys. Rev. B, 84, (2011); Tsutsui K., Murakami S., Phys. Rev. B, 86, (2012); Chen J., Jalil M.B.A., Tan S.G., AIP Advances, 2, (2012); Chung N.L., Jalil M.B.A., Tan S.G., AIP Advances, 2, (2012); Miron L.M., Gaudin G., Auffret S., Rodmacq B., Schuhl A., Pizzini S., Vogel J., Gambardella P., Nat. Mat., 9, (2010); Kim J., Shinha J., Hayashi M., Yamanouchi M., Fukami S., Suzuki T., Mitani S., Ohno H., Nat. Mat., 12, (2013); Tan S.G., Jalil M.B.A., Fujita T., Annals of Physics, 325, (2010); Jalil M.B.A., Tan S.G., IEEE. Trans.Magn, 46, (2010); Marchenko D., Varykhalov A., Scholz M.R., Bihlmayer G., Rashba E.I., Rybkin A., Shikin A.M., Rader O., Nat. Commun., 3, (2012)","","","American Institute of Physics Inc.","","","","","","21583226","","","","English","AIP Adv.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-84882755526" +"Tang L.; Xu Z.; Yang Z.","Tang, Ling (57191996015); Xu, Zhijun (58003618200); Yang, Zejin (22954858300)","57191996015; 58003618200; 22954858300","First-principles calculations of current-induced spin-transfer torques in magnetic domain walls","2013","International Journal of Modern Physics B","27","12","1350092","","","","2","10.1142/S0217979213500926","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84877739575&doi=10.1142%2fS0217979213500926&partnerID=40&md5=6dc2b226449476a5ef4b97a518fa0da8","Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China","Tang L., Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China; Xu Z., Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China; Yang Z., Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China","Current-induced spin-transfer torques (STTs) have been studied in Fe, Co and Ni domain walls (DWs) by the method based on the first-principles noncollinear calculations of scattering wavefunctions expanded in the tight-binding linearized muffin-tin orbital (TB-LMTO) basis. The results show that the out-of-plane component of nonadiabatic STT in Fe DW has localized form, which is in contrast to the typical nonlocal oscillating nonadiabatic torques obtained in Co and Ni DWs. Meanwhile, the degree of nonadiabaticity in STT is also much greater for Fe DW. Further, our results demonstrate that compared to the well-known first-order nonadiabatic STT, the torque in the third-order spatial derivative of local spin can better describe the distribution of localized nonadiabatic STT in Fe DW. The dynamics of local spin driven by this third-order torques in Fe DW have been investigated by the Landau-Lifshitz- Gilbert (LLG) equation. The calculated results show that with the same amplitude of STTs the DW velocity induced by this third-order term is about half of the wall speed for the case of the first-order nonadiabatic STT. © World Scientific Publishing Company..","current-induced domain wall motion; First-principles calculation; magnetic domain wall; spin-transfer torque","","","","","","Provincial Natural Science Foundation of Zhejiang, (Y13A040032, Y201121807); National Natural Science Foundation of China, NSFC, (11104247); China Postdoctoral Science Foundation, (2012M520666)","The authors acknowledge Prof. Ke Xia for suggesting the problem and Dr. Shuai Wang for useful discussion about the calculations. The authors are also grateful to Dr. Yuan Xu, Dr. Yong Wang and Dr. Rui Wang for technical assistance. We are grateful to: Ilja Turek for his TB-LMTO-SGF layer code; Anton Starikov for the TB-MTO code based upon sparse matrix techniques. The authors also acknowledge the financial support from the National Natural Science Foundation of China (Grant No: 11104247), China Postdoctoral Science Foundation (Grant No: 2012M520666), and the Provincial Natural Science Foundation of Zhejiang (Grant Nos: Y201121807 and Y13A040032).","Hayashi M., Et al., Phys. Rev. Lett., 96, (2006); Yamanouchi M., Et al., Phys. Rev. Lett., 96, (2006); Burrowes C., Et al., Nat. Phys., 6, (2010); Ilgaz D., Et al., Phys. Rev. Lett., 105, (2010); San Emeterio Alvarez L., Et al., Phys. Rev. Lett., 104, (2010); Miron I.M., Et al., Nat. Mater., 10, (2011); Schellekens A.J., Et al., Nat. Commun., 3, (2012); Koyama T., Et al., Nat. Nano., 7, (2012); Bauer U., Emori S., Beach G.S.D., Appl. Phys. Lett., 101, (2012); Yan P., Wang X.S., Wang X.R., Phys. Rev. Lett., 107, (2011); Chureemart P., Evans R.F.L., Chantrell R.W., Phys. Rev. B, 83, (2011); Khvalkovskiy A.V., Et al., Phys. Rev. B, 87, (2013); Tatara G., Kohno H., Shibata J., Phys. 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Rev. Lett., 92, (2004); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Waintal X., Viret M., Europhys. Lett., 65, (2004); Barnes S.E., Maekawa S., Phys. Rev. Lett., 95, (2005); Xiao J., Zangwill A., Stiles M.D., Phys. Rev. B, 73, (2006); Nguyen A.K., Skadsem H.J., Brataas A., Phys. Rev. Lett., 98, (2007); Thorwart M., Egger R., Phys. Rev. B, 76, (2007); Edwards D.M., Wessely O., J. Phys.: Condens. Matter, 21, (2009); Wang S., Xu Y., Xia K., Phys. Rev. B, 77, (2008); Wang S., Tang L., Xia K., Phys. Rev. B, 81, (2010); Xu Y., Wang S., Xia K., Phys. Rev. Lett., 100, (2008); Xia K., Et al., Phys. Rev. B, 73, (2006); Turek I., Et al., Electronic Structure of Disordered Alloys, Surfaces and Interfaces, (1997); Andersen O.K., Jepsen O., Phys. Rev. Lett., 53, (1984); Andersen O.K., Pawlowska Z., Jepsen O., Phys. Rev. B, 34, (1986); Tang L., Wang S., Mod. Phy. Lett. B, 22, (2008); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Ohe J.-I., Kramer B., Phys. Rev. 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(56226890200)","7103114636; 6506392457; 56226430600; 56226890200","Eddy current effects in the magnetization dynamics of ferromagnetic metal nanoparticles","2014","Journal of Applied Physics","116","4","043911","","","","6","10.1063/1.4891455","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84905837030&doi=10.1063%2f1.4891455&partnerID=40&md5=ccf04e862c0d921319fed91447c380ed","Sumy State University, UA-40007 Sumy, 2 Rimsky-Korsakov Street, Ukraine","Denisov S.I., Sumy State University, UA-40007 Sumy, 2 Rimsky-Korsakov Street, Ukraine; Lyutyy T.V., Sumy State University, UA-40007 Sumy, 2 Rimsky-Korsakov Street, Ukraine; Pedchenko B.O., Sumy State University, UA-40007 Sumy, 2 Rimsky-Korsakov Street, Ukraine; Babych H.V., Sumy State University, UA-40007 Sumy, 2 Rimsky-Korsakov Street, Ukraine","We develop an analytical model for describing the magnetization dynamics in ferromagnetic metal nanoparticles, which is based on the coupled system of the Landau-Lifshitz-Gilbert (LLG) and Maxwell equations. By solving Maxwell's equations in the quasi-static approximation and finding the magnetic field of eddy currents, we derive the closed LLG equation for the magnetization that fully accounts for the effects of conductivity. We analyze the difference between the LLG equations in metallic and dielectric nanoparticles and show that these effects can strongly influence the magnetization dynamics. As an example illustrating the importance of eddy currents, the phenomenon of precessional switching of magnetization is considered. © 2014 AIP Publishing LLC.","","Dynamics; Ferromagnetic materials; Ferromagnetism; Maxwell equations; Metal nanoparticles; Dielectric nanoparticles; Eddy-current effects; Landau-Lifshitz-Gilbert; Magnetic field of eddy currents; Magnetization dynamics; Maxwell's equations; Precessional switching; Quasistatic approximations; Magnetization","","","","","","","Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. 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Cancer, 5, (2005); Labhasetwar V., Leslie-Pelecky D.L., Biomedical Applications of Nanotechnology, (2007); Laurent S., Forge D., Port M., Roch A., Robic C., Elst L.V., Muller R.N., Chem. Rev., 108, (2008); Brown Jr. W.F., Magnetostatic Principles in Ferromagnetism, (1962); Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, (2001); Bertotti G., Mayergoyz I.D., Serpico C., Physica B, 343, (2004); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Alvarez L.F., Pla O., Chubykalo O., Phys. Rev. B, 61, (2000); Vagin D.V., Polyakov O.P., J. Appl. Phys., 105, (2009); Bragard J., Pleiner H., Suarez O.J., Vargas P., Gallas J.A.C., Laroze D., Phys. Rev. e, 84, (2011); Laroze D., Becerra-Alonso D., Gallas J.A.C., Pleiner H., IEEE Trans. Magn., 48, (2012); Back C.H., Weller D., Heidmann J., Mauri D., Guarisco D., Garwin E.L., Siegmann H.C., Phys. Rev. Lett., 81, (1998); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, (2000); Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 93, (2003); Sun Z.Z., Wang X.R., Phys. Rev. Lett., 97, (2006); Brown Jr. W.F., Phys. Rev., 130, (1963); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Coffey W.T., Kalmykov Yu.P., Waldron J.T., The Langevin Equation, (2004); Denisov S.I., Polyakov A.Yu., Lyutyy T.V., Phys. Rev. B, 84, (2011); Torres L., Lopez-Diaz L., Martinez E., Alejos O., IEEE Trans. Magn., 39, (2003); Torres L., Martinez E., Lopez-Diaz L., Alejos O., Physica B, 343, (2004); Hrkac G., Kirschner M., Dorfbauer F., Suess D., Ertl O., Fidler J., Schrefl T., J. Appl. Phys., 97, (2005); Martinez E., Lopez-Diaz L., Torres L., J. Appl. Phys., 99, (2006); Batygin V.V., Toptygin I.N., Problems in Electrodynamics, (1978); Landau L.D., Lifshitz E.M., Electrodynamics of Continuous Media, (1984)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84905837030" +"Fashami M.S.; Munira K.; Bandyopadhyay S.; Ghosh A.W.; Atulasimha J.","Fashami, Mohammad Salehi (55037499600); Munira, Kamaram (36844384200); Bandyopadhyay, Supriyo (57203099871); Ghosh, Avik W. (7403963862); Atulasimha, Jayasimha (6508238509)","55037499600; 36844384200; 57203099871; 7403963862; 6508238509","Switching of dipole coupled multiferroic nanomagnets in the presence of thermal noise: Reliability of nanomagnetic logic","2013","IEEE Transactions on Nanotechnology","12","6","6632926","1206","1212","6","41","10.1109/TNANO.2013.2284777","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84888180317&doi=10.1109%2fTNANO.2013.2284777&partnerID=40&md5=a8b21b7a028c7d8f6a904600b36ff0fe","Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Center for Materials for Information Technology, University of Alabama, AL 35405, United States; Department of Electrical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22903, United States","Fashami M.S., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Munira K., Center for Materials for Information Technology, University of Alabama, AL 35405, United States; Bandyopadhyay S., Department of Electrical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Ghosh A.W., Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22903, United States; Atulasimha J., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","The stress-induced switching behavior of a multiferroic nanomagnet, dipole coupled to a hard nanomagnet, is numerically studied by solving the stochastic Landau-Lifshitz-Gilbert equation for a single-domain macrospin state. Different factors were found to affect the switching probability in the presence of thermal noise at room temperature: 1) dipole coupling strength, 2) stress levels, and 3) stress withdrawal rates (ramp rates). We report that the thermal broadening of the magnetization distribution causes large switching error rates. This could render nanomagnetic logic schemes that rely on dipole coupling to perform Boolean logic operations impractical whether they are clocked by stress or field or other means. © 2002-2012 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; nanomagnetic logic (NML); reliability; straintronics-spintronics; thermal noise","Reliability; Thermal noise; Boolean logic operations; Landau-Lifshitz-Gilbert equations; Magnetization distribution; Nanomagnetic logic; Nanomagnetic logic (NML); straintronics-spintronics; Switching behaviors; Switching probability; Nanomagnetics","","","","","","","Cowburn R.P., Welland M.E., Room temperature magnetic quantum cellular automata, Science, 287, 5457, pp. 1466-1468, (2000); Csaba G., Imre A., Bernstein G.H., Porod W., Metlushko V., Nanocomputing by field-coupled nanomagnets, IEEE Transactions on Nanotechnology, 1, 4, pp. 209-213, (2002); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Single-domain circular nanomagnets, Physical Review Letters, 83, 5, pp. 1042-1045, (1999); Salahuddin S., Datta S., Interacting systems for self-correcting low power switching, Appl. Phys. Lett., 90, 9, pp. 093503-093503, (2007); Bennett C.H., The thermodynamics of computation-A review, Int. J. Theoretical Phys., 21, 12, pp. 905-940, (1982); Atulasimha J., Bandyopadhyay S., Bennett clocking of nanomagnetic logic using multiferroic single-domain nanomagnets, Appl. Phys. Lett., 97, 17, (2010); Fashami M.S., Roy K., Atulasimha J., Bandyopadhyay S., Magnetization dynamics, Bennett clocking and associated energy dissipation in multiferroic logic, Nanotechnol., 22, 15, pp. 155201-155210, (2011); Saheli Fashami M., Atulasimha J., Bandyopadhyay S., Magnetization dynamics, throughput and energy dissipation in a universal multiferroic nanomagnetic logic gate with fan-in and fan-out, Nanotechnol., 23, 10, pp. 105201-105210, (2012); D'Souza N., Atulasimha J., Bandyopadhyay S., Four-state nanomagnetic logic using multiferroics, J. Phys. D: Appl. Phys., 44, 26, pp. 265001-265007, (2011); D'Souza N., Atulasimha J., Bandyopadhyay S., Energy-Efficient Bennett clocking scheme for four-state multiferroic logic, IEEE Trans. Nanotechnol., 11, 2, pp. 418-425, (2012); Munira K., Nadri S., Forgues M.B., Salehi Fashami M., Atulasimha J., Bandyopadhyay S., Ghosh A.W., Regulating Stress Vs Dipolar Coupling to Maximize Error-delay Tradeoffs in Multiferroic Logic, (2012); Roy K., Bandyopadhyay S., Atulasimha J., Hybrid spintronics and straintronics: A magnetic technology for ultra low energy computing and signal processing, Appl. Phys. Lett., 99, pp. 063108-063110, (2011); Roy K., Bandyopadhyay S., Atulasimha J., Error-resilient Switching of A Bistable Switch Without Introducing Asymmetry in Its Potential Profile; Pertsev N.A., Kohlstedt H., Resistive switching via the converse magnetoelectric effect in ferromagnetic multilayers on ferroelectric substrates, Nanotechnology, 21, 47, pp. 475202-475208, (2010); Tiercelin N., Dusch Y., Klimov A., Giordano S., Preobrazhensky V., Pernod P., Room temperature magnetoelectric memory cell using stressmediated magnetoelastic switching in nanostructured multilayers, Appl. Phys. Lett., 99, 19, (2011); Nikonov D.E., Bourianoff G.I., Rowlands G., Krivorotov I.N., Strategies and tolerances of spin transfer torque switching, J. Appl. Phys., 107, 11, (2010); Spedalieri F.M., Jacob A.P., Nikonov D.E., Roychowdhury V.P., Performance of magnetic quantum cellular automata and limitations due to thermal noise, IEEE Trans. Nanotechnol., 10, 3, pp. 537-546, (2011); Csaba G., Porod W., Behavior of nanomagnet logic in the presence of thermal noise, Proc. 14th Int. Workshop Comput. Electron., pp. 1-4, (2010); Chikazumi S., Charap S.H., Physics of Magnetism., (1978); Lee K.J., Park N.Y., Lee T.D., Numerical study of spin relaxation by thermal fluctuation: Effect of shape anisotropy, Journal of Applied Physics, 89, 11, pp. 7460-7462, (2001); Brown G., Novotny M.A., Rikvold P.A., Langevin simulation of thermally activated magnetization reversal in nanoscale pillar, Phys. Rev. B, 64, 13, pp. 134422-134435, (2001); Strachan J.P., Chembrolu V., Acremann Y., Yu X.W., Tulapurkar A.A., Tyliszczak T., Katine J.A., Carey M.J., Scheinfein M.R., Siegmann H.C., Stohr J., Direct observation of spin-torque driven magnetization reversal through nonuniform modes, Phys. Rev. Lett., 100, pp. 247201-247204, (2008); Carlton D., Lambson B., Scholl A., Young A., Ashby P., Dhuey S., Bokor J., Investigation of defects and errors in nanomagnetic logic circuits, IEEE Trans. Nanotechnol., 11, 4, pp. 760-762, (2012); Abbundi R., Clark A., Anomalous thermal expansion and magnetostriction of single crystal Tb.27Dy.73Fe2, IEEE Trans. Magn., M-13, 5, pp. 1519-1520, (1977); Ried K., Schnell M., Schatz F., Hirscher M., Ludescher B., Sigle W., Kronmuller H., Crystallization behaviour and magnetic properties of magnetostrictive TbDyFe films, Physica Status Solidi (A) Applied Research, 167, 1, pp. 195-208, (1998); Kellogg R., Flatau A., Experimental investigation of terfenol-D's elastic modulus, Journal of Intelligent Material Systems and Structures, 19, 5, pp. 583-595, (2008); Walowski J., Kaufmann M.D., Lenk B., Hamann C., McCord J., Munzenberg M., Intrinsic and non-local Gilbert damping in polycrystalline nickel studied by Ti: Sapphire laser FS spectroscopy, J. Phys. D: Appl. Phys., 41, 16, pp. 164016-164025, (2008); Salehi Fashami M., Atulasimha J., Bandyopadhyay S., Energy Dissipation and Error Probability in Fault-tolerant Binary Switching, (2012); Behin-Aein B., Datta D., Salahuddin S., Datta S., Proposal for an all-spin logic device with built-in memory, Nature Nanotechnol., 5, 4, pp. 266-270, (2010); Li J., Nagaraj B., Liang H., Cao W., Lee C., Ramesh R., Ultrafast polarization switching in thin-film ferroelectrics, Appl. Phys. Lett., 84, 7, pp. 1174-1176, (2004); Technology Administration, (1999); Dewar G., Effect of the large magnetostriction of Terfenol-D on microwave transmission, Journal of Applied Physics, 81, 8, pp. 5713-5715, (1997)","","","","","","","","","1536125X","","","","English","IEEE Trans. Nanotechnol.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84888180317" +"Wegrowe J.-E.; Olive E.","Wegrowe, J.-E. (7004315688); Olive, E. (6602922371)","7004315688; 6602922371","Geometrical phase and inertial regime of the magnetization: Hannay angle and magnetic monopole","2015","Proceedings of SPIE - The International Society for Optical Engineering","9551","","95511I","","","","2","10.1117/12.2191127","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84951153409&doi=10.1117%2f12.2191127&partnerID=40&md5=33d3f777ee3b678790ff27c7a2246d69","Laboratoire des solides irradiés, Ecole Polytechnique, CEA-DSM-IRAMIS and CNRS 7642, Palaiseau Cedex, 91128, France; GREMAN, UMR 7347, Université François Rabelais-CNRS, Parc de Grandmont, Tours, 37200, France","Wegrowe J.-E., Laboratoire des solides irradiés, Ecole Polytechnique, CEA-DSM-IRAMIS and CNRS 7642, Palaiseau Cedex, 91128, France; Olive E., GREMAN, UMR 7347, Université François Rabelais-CNRS, Parc de Grandmont, Tours, 37200, France","It is well known that the Landau-Lifshitz-Gilbert (LLG) equation for a macroscopic magnetic moment find its limit of validity at very short time scales or equivalently at very high frequencies. The reason for this limit of validity is well understood in terms of separation of the characteristic times between slow (the magnetization) and fast (the environment) degrees of freedom, as pointed-out in the stochastic derivation of the LLG equation first proposed by W. F. Brown in 1963. Indeed, the ferromagnetic moment is a slow collective variable, but fast degrees of freedom are also playing a role in the dynamics, and especially the variation of the angular momentum responsible for inertia. In the last couple of years, the generalization of the LLG equation with inertia (ILLG) has been derived by different means (see list of references). The signature of the inertial regime of the magnetization is the nutation that can be measured by resonance experiments (but it has not been observed up to know). We developed an approach in terms of geometrical phase (defining the corresponding Hannay angle, which is the classical analog to the quantum Berry phase : see references), that has recently been used with success to analogous problems. We calculated the Hannay angle for the precession of the magnetization in the case of the inertial effect, and the corresponding magnetic monopole. This analysis allows the slow vs. fast variable expansion to be calculated in the specific case of pure precession. © 2015 SPIE.","Berry phase; Fast vs slow degrees of freedom; Hannay angle; Inertial regime of the magnetization; Precession and nutation","Fruits; Magnetic moments; Magnetism; Magnetization; Magnetoelectronics; Mechanics; Stochastic systems; Berry phase; Collective variables; Ferromagnetic moments; Hannay angle; Inertial regimes; Landau-Lifshitz-Gilbert equations; Precession and nutation; Very high frequency; Degrees of freedom (mechanics)","","","","","","","Gilbert T.H., Formulations, Fundations and Applications of the Phenomenological Theory of Ferromagnetism, (1956); Berry M.V., Shukla P., Slow manifold and Hannay angle in the spinning top, Eur. J. Phys., 32, pp. 115-127, (2011); Wegrowe J.-E., Ciornei M.-C., Magnetization dynamics, gyromagnetic relation, and inertial effects, Am. J. Phys., 80, (2012); Ciornei M.-C., Rubi J.M., Wegrowe J.-E., Magnetization dynamics in the inertial regime: Nutation predicted at short time scales, Phys. Rev. B, 83, pp. 020410R1-020410R4, (2011); Faehnle M., Steiauf D., Illg C., It Generalized Gilbert equation including inertial damping : Derivation from an extended breathing Fermi surface model, Phys. Rev. B, 84, (2011); Olive E., Lansac Y., Wegrowe J.-E., Beyond ferromagnetic resonance : The inertial regime of the magnetization, Appl. Phys. Lett., 100, (2012); Bhattacharjee S., Nordstrom L., Fransson J., Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles, Phys. Rev. Lett., 108, (2012); Olive E., Lansac Y., Meyer M., Hayoun M., Wegrowe J.-E., Deviation from Landau-Lifshitz-Gilbert equation in the inertial regime of the magnetization, J. Appl. Phys., 117, (2015); Berry M.V., Quantal phase factors accompanying adiabatic changes, Proc. R. Soc. Lond A, 392, pp. 45-57, (1984); Hannay J.H., Angle variable holonomy in adiabatic excusion of an integrable Hamiltonian, J. Phys. A: Math. Gen., 18, pp. 221-230, (1985); Griffiths D.J., Hnizdo V., Mansuripur's paradox, Am. J. Phys., 81, (2013)","","Drouhin H.-J.; Wegrowe J.-E.; Razeghi M.","SPIE","The Society of Photo-Optical Instrumentation Engineers (SPIE)","Spintronics VIII","9 August 2015 through 13 August 2015","San Diego","117086","0277786X","978-162841717-3","PSISD","","English","Proc SPIE Int Soc Opt Eng","Conference paper","Final","","Scopus","2-s2.0-84951153409" +"Greenwood A.D.; French D.M.; Hoff B.W.; Heidger S.L.","Greenwood, Andrew D. (7102457649); French, David M. (25624407200); Hoff, Brad W. (8694738200); Heidger, Susan L. (6603263019)","7102457649; 25624407200; 8694738200; 6603263019","Finite-difference time-domain/Landau-Lifshitz-Gilbert algorithm for modeling ferrites with hysteresis","2014","2014 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2014 - Proceedings","","","6955430","48","","","1","10.1109/USNC-URSI.2014.6955430","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84916232836&doi=10.1109%2fUSNC-URSI.2014.6955430&partnerID=40&md5=6795f6281d3006074fc6ff0b99799256","Air Force Research Laboratory, Directed Energy Dirctorate, Kirtland AFB, NM, United States","Greenwood A.D., Air Force Research Laboratory, Directed Energy Dirctorate, Kirtland AFB, NM, United States; French D.M., Air Force Research Laboratory, Directed Energy Dirctorate, Kirtland AFB, NM, United States; Hoff B.W., Air Force Research Laboratory, Directed Energy Dirctorate, Kirtland AFB, NM, United States; Heidger S.L., Air Force Research Laboratory, Directed Energy Dirctorate, Kirtland AFB, NM, United States","The finite-difference time-domain (FDTD) method is a simple, robust tool for a variety of electromagnetic modeling scenarios. In order to model magnetic ferrite materials, the FDTD method is coupled with the Landau-Lifshitz-Gilbert (LLG) equation. The LLG equation is discretized by defining a magnetization vector at the center of each cell. The update at each time step then proceeds by (1) update the electric field with Ampere's law, (2) update the magnetic flux density with Faraday's law, (3) interpolate the magnetic field to the cell centers, (4) update the magnetization vector with the LLG equation, (5) interpolate the magnetization to the magnetic field locations on the Yee FDTD staggered grid, (6) update the magnetic field using B = μ0 (H + M) where B is the magnetic flux density, μ0 is the permeability of free space, H is the magnetic field, and M is the magnetization. © 2014 IEEE.","","Computational electromagnetics; Electric fields; Finite difference time domain method; Magnetic fields; Magnetic flux; Magnetization; Vector spaces; Ampere's law; Cell centers; Electromagnetic modeling; Faraday's laws; Landau-Lifshitz-Gilbert equations; Magnetic ferrites; Magnetization vector; Staggered grid; Time domain analysis","","","","","","","","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Antennas and Propagation Society; The Institute of Electrical and Electronics Engineers","2014 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2014","6 July 2014 through 11 July 2014","Memphis","109146","","978-147993746-2","","","English"," USNC-URSI Radio Sci. Meet. (Jt. AP-S Symp.), USNC-URSI - Proc.","Conference paper","Final","","Scopus","2-s2.0-84916232836" +"Giordano A.; Finocchio G.; Torres L.; Carpentieri M.; Azzerboni B.","Giordano, A. (55493451200); Finocchio, G. (55902853000); Torres, L. (56926909600); Carpentieri, M. (8590004000); Azzerboni, B. (57188761517)","55493451200; 55902853000; 56926909600; 8590004000; 57188761517","Semi-implicit integration scheme for Landau-Lifshitz-Gilbert-Slonczewski equation","2012","Journal of Applied Physics","111","7","07D112","","","","65","10.1063/1.3673428","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861746999&doi=10.1063%2f1.3673428&partnerID=40&md5=ae92c740b34a950a42d7e948c92e1764","Department of Fisica della Materia e Ingegneria Elettronica, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Department of Física Aplicada, Universidad de Salamanca, Salamanca 37008, Plaza de la Merced, Spain; Department of Elettronica, Informatica e Sistemistica, University of Calabria, I-87036, Rende (CS), Via P. Bucci 42C, Italy","Giordano A., Department of Fisica della Materia e Ingegneria Elettronica, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Finocchio G., Department of Fisica della Materia e Ingegneria Elettronica, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Torres L., Department of Física Aplicada, Universidad de Salamanca, Salamanca 37008, Plaza de la Merced, Spain; Carpentieri M., Department of Elettronica, Informatica e Sistemistica, University of Calabria, I-87036, Rende (CS), Via P. Bucci 42C, Italy; Azzerboni B., Department of Fisica della Materia e Ingegneria Elettronica, University of Messina, 98166 Messina, Salita Sperone 31, Italy","This paper shows how to implement a semi-implicit algorithm based on the Adams-Bashforth algorithm as a predictor, and a second order Adams-Moulton procedure as a corrector in the Landau-Lifshitz-Gilbert-Slonczewski equation. We compare the results with a Runge-Kutta scheme of the 5th order, while for the standard problem #4 (and, in general, for the LLG equation) the computational speeds are of the same order, and we found better performance when the thermal fluctuations or the spin-polarized currents are taken into account. © 2012 American Institute of Physics.","","Runge Kutta methods; Spin fluctuations; Adams-Bashforth; Adams-Moulton; Computational speed; Integration scheme; LLG equation; Runge-Kutta; Second orders; Semi-implicit; Spin-polarized currents; Standard problems; Thermal fluctuations; Algorithms","","","","","","","Brown W.F., Micromagnetics, (1963); Cardelli E., Della Torre E., Pinzaglia E., J. Appl. Phys., 93, (2003); Bertotti G., Hysteresis in Magnetism, (1998); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 93, (2003); Romeo A., Finocchio G., Carpentieri M., Torres L., Consolo G., Azzerboni B., Physica B, 403, (2008); Slonczewski J., J. Magn. Magn. Mater., 159, (1996); Finocchio G., Ozatay O., Torres L., Buhrman R.A., Ralph D.C., Azzerboni B., Phys. Rev. B, 78, (2008); Finocchio G., Krivorotov I., Cheng X., Torres L., Azzerboni B., Phys. Rev. B, 83, (2011); Finocchio G., Carpentieri M., Azzerboni B., Torres L., Martinez E., Lopez-Diaz L., J. Appl. Phys., 99, (2006); Brown Jr. W.F., Phys. Rev., 130, (1963)","G. Finocchio; Department of Fisica della Materia e Ingegneria Elettronica, University of Messina, 98166 Messina, Salita Sperone 31, Italy; email: gfinocchio@unime.it","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-84861746999" +"Hongtao W.; Zhimin Y.; Sann C.K.","Hongtao, Wang (55356814900); Zhimin, Yuan (13205642500); Sann, Chan Kheong (7406033939)","55356814900; 13205642500; 7406033939","Hysteresis loop testing for continuous media by energy minimization","2014","MSSC 2014 - Digests of Magnetics Symposium 2014: Celebrating 50 Years of IEEE Magnetics Society","","","6947940","","","","0","10.1109/MSSC.2014.6947940","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84915747158&doi=10.1109%2fMSSC.2014.6947940&partnerID=40&md5=595ea2090f8ff5ef867e02403204d03f","Data Storage Institute, A STAR (Agency for Science, Technology and Research), Singapore","Hongtao W., Data Storage Institute, A STAR (Agency for Science, Technology and Research), Singapore; Zhimin Y., Data Storage Institute, A STAR (Agency for Science, Technology and Research), Singapore; Sann C.K., Data Storage Institute, A STAR (Agency for Science, Technology and Research), Singapore","Hysteresis Loop has been investigated for continuous media by using the energy minimization approach. The domain wall energy is included into the total free energy which is being minimized directly to achieve the equilibrium status of the discretized continuous media. The effects of exchange coupling constant on the hysteresis loop also get studied. It is carried out to make a comparison among the micromagnetic approaches based on the Landau-Lifshitz-Gilbert (LLG) equation and the total free energy equations with and without domain wall energy. All rights reserved - © Copyright 2014 IEEE.","continuous media; energy minimization; hysteresis loop; micromagnetics; perpendicular magnetic recording","Domain walls; Free energy; Hysteresis; Hysteresis loops; Continuous media; Domain wall energy; Energy minimization; Exchange coupling constants; Landau-Lifshitz-Gilbert equations; Micromagnetics; Perpendicular magnetic recording; Total free energy; Magnetic materials","","","","","","","Peng Y., Wu X.W., Pressesky J., Ju G.P., Scholz W., Chantrell R.W., Cluster size and exchange dispersion in perpendicular magnetic media, Journal of Applied Physics, 109, (2011); Yasumori J., Sonobe Y., Greaves S., Tham K.K., Approach to high-density recording using CGC structure, IEEE Transactions on Magnetics, 38, 2, (2009); Landau L., Lifshitz E., Physics. Z. Sowjetunion, 8, (1935); Aharoni A., Domain Walls and Micromagnetics; Brown W.F., Micromagnetics, (1963); Tu Y., Determination of magnetization of micromagnetics wall in bubble domains by direct minimization, Journal of Applied Physics, 42, 13, (1971); Berkov D.V., Ramstock K., Hubert A., Solving micromagnetics problems, Physics Stat., Sol. (A), 137, (1993)","","","Institute of Electrical and Electronics Engineers Inc.","IEEE Magnetics Society Singapore Chapter","50th Magnetics Symposium of Singapore Chapter, MSSC 2014","22 September 2014 through 23 September 2014","Singapore","109086","","978-147997382-8","","","English","MSSC - Dig. Magn. Symp.: Celebr. Years IEEE Magn. Soc.","Conference paper","Final","","Scopus","2-s2.0-84915747158" +"Castillo I.P.; Dupic T.","Castillo, Isaac Pérez (10540590100); Dupic, Thomas (56203528900)","10540590100; 56203528900","Reunion Probabilities of N One-Dimensional Random Walkers with Mixed Boundary Conditions","2014","Journal of Statistical Physics","156","3","","606","616","10","5","10.1007/s10955-014-1017-8","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84902303616&doi=10.1007%2fs10955-014-1017-8&partnerID=40&md5=fa5803f00c7ec3bb83297c44ab6965b6","Departamento de Sistemas Complejos, Instituto de Física, UNAM, 01000 Mexico, D.F, P.O. Box 20-364, Mexico; Department of Mathematics, King's College London, London, WC2R 2LS, Strand, United Kingdom","Castillo I.P., Departamento de Sistemas Complejos, Instituto de Física, UNAM, 01000 Mexico, D.F, P.O. Box 20-364, Mexico, Department of Mathematics, King's College London, London, WC2R 2LS, Strand, United Kingdom; Dupic T., Department of Mathematics, King's College London, London, WC2R 2LS, Strand, United Kingdom","In this work we extend the results of the reunion probability of N one-dimensional random walkers to include mixed boundary conditions between their trajectories. The level of the mixture is controlled by a parameter c, which can be varied from c=0 (independent walkers) to c → ∞ (vicious walkers). The expressions are derived by using Quantum Mechanics formalism (QMf) which allows us to map this problem into a Lieb-Liniger gas (LLg) of N one-dimensional particles. We use Bethe ansatz and Gaudin's conjecture to obtain the normalized wave-functions and use this information to construct the propagator. As it is well-known, depending on the boundary conditions imposed at the endpoints of a line segment, the statistics of the maximum heights of the reunited trajectories have some connections with different ensembles in Random Matrix Theory. Here we seek to extend those results and consider four models: absorbing, periodic, reflecting, and mixed. In all four cases, the probability that the maximum height is less or equal than L takes the form (Formula Presented), where AN is a normalization constant, VN(k) contains a deformed and weighted Vandermonde determinant, and ΩB is the solution set of quasi-momenta k obeying the Bethe equations for that particular boundary condition. © 2014 Springer Science+Business Media New York.","Bethe ansatz; Random matrices; Random walkers; Vicious walkers","","","","","","","","Adler M., van Moerbeke P., Vanderstichelen D., Non-intersecting brownian motions leaving from and going to several points, Physica D, 241, 5, pp. 443-460, (2012); Baik J., Random vicious walks and random matrices, Commun. Pure Appl. Math., 53, 11, pp. 1385-1410, (2000); Batchelor M., Guan X., Oelkers N., Lee C., The 1d interacting bose gas in a hard wall box, J. Phys. A, 38, 36, (2005); Bleher P., Delvaux S., Kuijlaars A.B.J., Random matrix model with external source and a constrained vector equilibrium problem, Commun. Pure Appl. Math., 64, 1, pp. 116-160, (2011); Borodin A., Kuan J., Random surface growth with a wall and plancherel measures for o(∞), Commun. Pure Appl. Math., 63, 7, pp. 831-894, (2010); Daems E., Kuijlaars A., Multiple orthogonal polynomials of mixed type and non-intersecting brownian motions, J Approx. Theory, 146, 1, pp. 91-114, (2007); De Nardis J., Wouters B., Brockmann M., Caux J.S., Variational solution for the interaction quench in the lieb-liniger bose gas, (2013); Erban R., Chapman S.J., Reactive boundary conditions for stochastic simulations of reaction-diffusion processes, Phys. Biol., 4, 1, (2007); Ferrari P.L., Praehofer M., One-dimensional stochastic growth and Gaussian ensembles of random matrices, Proceedings of ""Inhomogeneous Random Systems 2005"", 12, pp. 203-234, (2006); Forrester P.J., Random walks and random permutations, J. Phys. A, 34, 31, (2001); Forrester P.J., Majumdar S.N., Schehr G., Non-intersecting brownian walkers and yang-mills theory on the sphere, Nucl. Phys. B, 844, 3, pp. 500-526, (2011); Gaudin M., Boundary energy of a bose gas in one dimension, Phys. Rev. A, 4, pp. 386-394, (1971); Gaudin M., McCoy B.M., Wu T.T., Normalization sum for the bethe's hypothesis wave functions of the heisenberg-ising chain, Phys. Rev. D, 23, pp. 417-419, (1981); Johansson K., Discrete polynuclear growth and determinantal processes, Commun. Math. Phys., 242, 1-2, pp. 277-329, (2003); Katori M., Tanemura H., Symmetry of matrix-valued stochastic processes and noncolliding diffusion particle systems, J. Math. Phys., 45, 8, pp. 3058-3085, (2004); Korepin V.E., Calculation of norms of bethe wave functions, Commun. Math. Phys., 86, 3, pp. 391-418, (1982); Lieb E.H., Liniger W., Exact analysis of an interacting bose gas. i. The general solution and the ground state, Phys. Rev., 130, 4, (1963); Majumdar S.N., Brownian functionals in physics and computer science, Curr. Sci., 89, (2005); Nadal C., Majumdar S.N., Nonintersecting brownian interfaces and wishart random matrices, Phys. Rev. E, 79, (2009); Nagao T., Dynamical correlations for vicious random walk with a wall, Nucl. Phys. B, 658, 3, pp. 373-396, (2003); Novak J., Vicious walkers and random contraction matrices, Int. Math. Res. Notices, 17, pp. 3310-3327, (2009); Rambeau J., Schehr G., Extremal statistics of curved growing interfaces in 1+1 dimensions, Eur. Lett., 91, 6, (2010); Schehr G., Majumdar S.N., Comtet A., Randon-Furling J., Exact distribution of the maximal height of p vicious walkers, Phys. Rev. Lett., 101, (2008); Schehr G., Majumdar S.N., Comtet A., Forrester P.J., Reunion probability of n vicious walkers: typical and large fluctuations for large n, J. Stat. Phys, pp. 1-40, (2013); Sklyanin E.K., Boundary conditions for integrable quantum systems, J. Phys. A, 21, 10, (1988); Takahashi M., Thermodynamics of One-Dimensional Solvable Models, (2005); Tracy C.A., Widom H., Nonintersecting brownian excursions, Ann. Appl. Probab., 17, pp. 953-979, (2007); Zinn-Justin J., Quantum Field Theory and Critical Phenomena, (2002)","I. P. Castillo; Departamento de Sistemas Complejos, Instituto de Física, UNAM, 01000 Mexico, D.F, P.O. Box 20-364, Mexico; email: isaacpc@fisica.unam.mx","","Springer Science and Business Media, LLC","","","","","","00224715","","","","English","J. Stat. Phys.","Article","Final","","Scopus","2-s2.0-84902303616" +"Denisov S.I.; Lyutyy T.V.; Babych H.V.; Pedchenko B.O.","Denisov, S.I. (7103114636); Lyutyy, T.V. (6506392457); Babych, H.V. (56226890200); Pedchenko, B.O. (56226430600)","7103114636; 6506392457; 56226890200; 56226430600","Contribution of the magnetic field of eddy currents to the gilbert damping parameter","2014","Journal of Nano- and Electronic Physics","6","2","02011","","","","1","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84903123133&partnerID=40&md5=d9eebe9b426d9d4302e0d65e43847eef","Sumy State University, 40007 Sumy, 2, Rimsky Korsakov Str., Ukraine","Denisov S.I., Sumy State University, 40007 Sumy, 2, Rimsky Korsakov Str., Ukraine; Lyutyy T.V., Sumy State University, 40007 Sumy, 2, Rimsky Korsakov Str., Ukraine; Babych H.V., Sumy State University, 40007 Sumy, 2, Rimsky Korsakov Str., Ukraine; Pedchenko B.O., Sumy State University, 40007 Sumy, 2, Rimsky Korsakov Str., Ukraine","We study the role of the magnetic field of eddy currents, which are induced in conducting singledomain particles of spherical form, in the magnetization dynamics. To describe the dynamic behavior of magnetization and electromagnetic field generating by the time-dependent magnetization, we use the coupled system of the Landau-Lifshitz-Gilbert (LLG) and Maxwell equations. Assuming that the magnetization direction depends on time in an arbitrary way, we find the solution of the Maxwell equations in the quasi-stationary approximation and calculate the averaged (over the particle volume) magnetic field of eddy currents. Considering this field as an extra contribution to the effective magnetic field acting on the particle magnetic moment, we derive the LLG equation in which the influence of eddy currents is completely accounted for by introducing an additional Gilbert damping parameter of electrodynamic origin. © 2014.","Conducting single-domain particles; Eddy currents; Gilbert damping parameter; Landau-lifshitz-gilbert equation; Maxwell equations; Quasi-stationary approximation","","","","","","","","Chudnovsky E.M., Tejada J., Macroscopic Quantum Tunneling of the Magnetic Moment, (1998); Gammaitoni L., Hangg P., Jung P., Marchesoni F., Rev. Mod. Phys., 70, (1998); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, (2000); Kaka S., Russek S.E., Thirion C., Wernsdorfer W., Mailly D., Nature Mater., 2, (2003); Woltersdorf G., Back C.H., Phys. Rev. Lett., 99, (2007); Ross C.A., Annu. Rev. Mater. Res., 31, (2001); Terris B.D., Thomson T., J. Phys. D, 38, (2005); Zutic I., Fabian J., Das Sarma S., Rev. Mod. Phys., 76, (2004); Maekawa S., Concepts in Spin Electronics, (2006); Pankhurst Q.A., Connolly J., Jones S.K., Dobson J., J. Phys. D: Appl. Phys., 36, (2003); Hergt R., Dutz S., Muller R., Zeisberger M., J. Phys.: Condens. Matter., 18, (2006); Laurent S., Forge D., Port M., Roch A., Robic C., Vander Elst L., Muller R.N., Chem. Rev., 108, (2008); Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. Magn., 40, (2004); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Brown Jr. W.F., 130, (1963); Coffey W.T., Kalmykov Y.P., Waldron J.T., The Langevin Equation, (2004); Denisov S.I., Trohidou K.N., Phys. Rev. B, 64, (2001); Denisov S.I., Lyutyy T.V., Trohidou K.N., Phys. Rev. B, 67, (2003); Denisov S.I., Lyutyy T.V., Hangg P., Trohidou K.N., Phys. Rev. B, 74, (2006); Denisov S.I., Lyutyy T.V., Hangg P., 97, (2006); Denisov S.I., Sakmann K., Talkner P., Hangg P., 75, (2007); Denisov S.I., Polyakov A.Y., Lyutyy T.V., Phys. Rev. B, 84, (2011); Ray S.S., Okamoto M., Prog. Polym. Sci., 28, (2003); Hussain F., Hojjati M., Okamoto M., Gorga R.E., J. Compos. Mater., 40, (2006); Bertotti G., Hysteresis in Magnetism, (1998); Martinez E., Lopez-Diaz L., Torres L., J. Appl. Phys., 99, (2006); Lakshmanan M., Phil. Trans. R. Soc. A, 369, (2011); Mayergoyz I.D., Serpico C., Shimizu Y., J. Appl. Phys., 87, (2000); Mrak I.C., Arch. Comput. Methods Eng., 15, (2008); Landau L.D., Lifshitz E.M., Electrodynamics of Continuous Media, (1984); Polyanin A.D., Handbook o fLinear Partial Differential Equations for Engineers and Scientists, (2002); Prudnikov A.P., Brychkov Y.A., Marichev O.I., Integrals and Series, 1, (1986)","","","Sumy State University","","","","","","20776772","","","","Russian","J. Nano. Electron. Phys.","Article","Final","","Scopus","2-s2.0-84903123133" +"Tanaka H.; Nakamura K.; Ichinokura O.","Tanaka, Hideaki (55624472145); Nakamura, Kenji (55516112700); Ichinokura, Osamu (7003759274)","55624472145; 55516112700; 7003759274","Iron loss calculation by incorporating LLG equation into magnetic circuit model","2013","2013 15th European Conference on Power Electronics and Applications, EPE 2013","","","6631860","","","","1","10.1109/EPE.2013.6631860","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84890215841&doi=10.1109%2fEPE.2013.6631860&partnerID=40&md5=fd6fc928263b99db3a5e1768dc1f3003","Tohoku Univ., Aramaki, Aoba-ku 980-8579, Sendai, Aoba 6-6-05, Japan","Tanaka H., Tohoku Univ., Aramaki, Aoba-ku 980-8579, Sendai, Aoba 6-6-05, Japan; Nakamura K., Tohoku Univ., Aramaki, Aoba-ku 980-8579, Sendai, Aoba 6-6-05, Japan; Ichinokura O., Tohoku Univ., Aramaki, Aoba-ku 980-8579, Sendai, Aoba 6-6-05, Japan","This paper presents an iron loss calculation by incorporating the Landau-Lifshitz-Gilbert (LLG) equation into a magnetic circuit model. In the proposed model, dc hysteresis loss is calculated by the LLG equation, and eddy current loss is calculated by a magnetic inductance. The validity is proved by comparing with the catalog values. © 2013 IEEE.","Hysteresis modeling; LLG equation; Magnetic circuit model; Simulation","Circuit theory; Hysteresis; Magnetic circuits; Power electronics; Eddy current-loss; Hysteresis modeling; Iron loss calculations; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic circuit model; Magnetic inductance; Simulation; Circuit simulation","","","","","","","Jiles D.C., Atherton D.L., Theory of ferromagnetic hysteresis, J. Appl. Phys., 55, 6, pp. 2115-2120, (1984); Chua L.O., Stromsmoe K.A., Lumped-circuit models for nonlinear inductors exhibiting hysteresis loops, IEEE Trans. Circuit Theory, 17, 4, pp. 564-574, (1970); Della E., Torre: Magnetic Hysteresis, (1999); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogenious alloys, Phil. Trans. Roy. Soc. A, 240, pp. 599-642, (1948); Nakatani Y., Uesaka Y., Hayashi N., Direct solution of the landau-lifshitz-gilbert equation for micromagnetics, Jpn. J. Appl. Phys., 28, pp. 2485-2087, (1989); Karapetoff V., The Magnetic Circuit, (1911); Nakamura K., Ichinokura O., Operation analysis for electrical machinery based on reluctance network, IEEJ Transactions on Fundamentals and Materials, 126, pp. 150-156, (2006); Hayashi N., Saito K., Nakatani Y., Calculation of demagnetizing field distribution based on fast fourier transform of convolution, Jpn. J. Appl. Phys., 35, pp. 6065-6073, (1996); Lebecki K.M., Donahue M.J., Gutowski M.W., Periodic boundary conditions for demagnetization interactions in micromagnetic simulations, J. Phys. D, Appl. Phys., 41, (2008); Zhu J.-G., Neal Bertram H., Micromagnetic studies of thin metallic films, J. Appl. Phys., 63, pp. 3248-3253, (1988); Uesaka Y., Shimizu K., Kadooka Y., Magnetic hysteresis by using micromagnetics, The 34th Annual Conference on MAGNETICS in Japan, (2010)","","","","","2013 15th European Conference on Power Electronics and Applications, EPE 2013","2 September 2013 through 6 September 2013","Lille","101325","","978-147990116-6","","","English","Eur. Conf. Power Electron. Appl., EPE","Conference paper","Final","","Scopus","2-s2.0-84890215841" +"Meenakshisundaram N.; Sabareesan P.; Vignesh L.","Meenakshisundaram, N. (57219599510); Sabareesan, P. (35192369200); Vignesh, L. (59514174400)","57219599510; 35192369200; 59514174400","Tailoring of bandgaps in magnonic anti dot waveguides by varying bias field","2014","Asian Journal of Applied Sciences","7","8","","814","818","4","0","10.3923/ajaps.2014.814.818","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84907466412&doi=10.3923%2fajaps.2014.814.818&partnerID=40&md5=292f1daed3abfc983bf946e7147afd7e","Centre for Nonlinear Science and Engineering (CeNSE), SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India; School of Electrical and Electronics Engineering, SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India","Meenakshisundaram N., Centre for Nonlinear Science and Engineering (CeNSE), SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India, School of Electrical and Electronics Engineering, SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India; Sabareesan P., Centre for Nonlinear Science and Engineering (CeNSE), SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India, School of Electrical and Electronics Engineering, SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India; Vignesh L., School of Electrical and Electronics Engineering, SASTRA University, Thirumalaisamudram, Thanjavur, 613401, India","Magnonic crystals are periodic composites of magnetic materials for propagating spin waves. The periodic modulation in magnonic crystal plays a vital role in the formation of bandgaps at the Brillouin Zone (BZ) boundaries leading towards possible applications in spin wave filters. In this study, we explore the possibility of tailoring the magnonic bandgap in one-dimensional (ID) square antidot waveguide structures by micromagnetic simulation. The space-time variations of magnetization in these structures are obtained by solving the Landau-Lifshitz-Gilbert (LLG) equation using OOMMF by applying spatially and temporally varying “sine” function normal to the waveguide plane in presence of a bias field of strength 1.01 and 0.505 T along the length of the waveguide. The dispersion relations are obtained by 2D discrete Fourier transform of the space-time data. We have investigated how the bias field affects the magnonic band structures and the corresponding bandgaps for four different materials. From the results we clearly observe a downward shifting of bandgaps towards lower frequency when the biasing field is decreased while the width of the bandgap remains same. Hence, it provides a simplest way for designing spin wave filters of different frequency regimes. © 2014 Knowledgia Review, Malaysia.","LLG equation; Magnetic thin films; Spin waves filters","","","","","","","","Barman S., Barman A., Otani Y., Dynamics of 1-D chains of magnetic vortices in response to local and global excitations, IEEE Trans. Magn., 46, pp. 1342-1345, (2010); Chi K.H., Zhu Y., Tsai C.S., Two-dimensional magnonic crystal with periodic thickness variation in yig layer for magnetostatic volume wave propagation, IEEE Trans. Magn., 49, pp. 1000-1004, (2013); Donahue M., Porter D.G., OOMMF user’s guide, version 1.0, (1999); Klos J.W., Sokolovskyy M.L., Mamica S., Krawczyk M., The impact of the lattice symmetry and the inclusion shape on the spectrum of 2D magnonic crystals, J. Appied Phys, 111, (2012); Kumar D., Sabareesan P., Wang W., Fangohr H., Barman A., Effect of hole shape on spin-wave band structure in one-dimensional magnonic antidot waveguide, J. Applied Phys, 114, (2013); Kumar D., Klos J.W., Krawczyk M., Barman A., Magnonic band structure, complete bandgap and collective spin wave excitation in nanoscale two-dimensional magnonic crystals, J. Applied Phys, 115, (2014); Lahtinen T.H.E., Franke K.J.A., Van Dijken S., Electric-field control of magnetic domain wall motion and local magnetization reversal, Sci. Rep., 2, pp. 258-264, (2012); Ma F.S., Lim H.S., Zhang V.L., Wang Z.K., Piramanayagam S.N., Et al., Band structures of exchange spin waves in one-dimensional bi-component magnonic crystals, J. Applied Phys, 111, (2012); Madami M., Tacchi S., Gubbiotti G., Carlotti G., Ding J., Et al., Spin wave dispersion in permalloy antidot array with alternating holes diameter, IEEE Trans. Magn., 49, pp. 3093-3096, (2013)","","","knowledgia review","","","","","","19963343","","","","English","Asian J. Appl. Sci.","Article","Final","","Scopus","2-s2.0-84907466412" +"Salehi Fashami M.; Atulasimha J.; Bandyopadhyay S.","Salehi Fashami, Mohammad (55037499600); Atulasimha, Jayasimha (6508238509); Bandyopadhyay, Supriyo (57203099871)","55037499600; 6508238509; 57203099871","Magnetization dynamics, throughput and energy dissipation in a universal multiferroic nanomagnetic logic gate with fan-in and fan-out","2012","Nanotechnology","23","10","105201","","","","72","10.1088/0957-4484/23/10/105201","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84857611617&doi=10.1088%2f0957-4484%2f23%2f10%2f105201&partnerID=40&md5=ccc907b9d590f98069c139117cb0caa3","Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","Salehi Fashami M., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Atulasimha J., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Bandyopadhyay S., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","The switching dynamics of a multiferroic nanomagnetic NAND gate with fan-in/fan-out is simulated by solving the Landau-Lifshitz-Gilbert (LLG) equation while neglecting thermal fluctuation effects. The gate and logic wires are implemented with dipole-coupled two-phase (magnetostrictive/piezoelectric) multiferroic elements that are clocked with electrostatic potentials of ∼50mV applied to the piezoelectric layer generating 10.1MPa stress in the magnetostrictive layers for switching. We show that a pipeline bit throughput rate of ∼0.5GHz is achievable with proper magnet layout and sinusoidal four-phase clocking. The gate operation is completed in 2ns with a latency of 4ns. The total (internal+external) energy dissipated for a single gate operation at this throughput rate is found to be only ∼500kT in the gate and ∼1250kT in the 12-magnet array comprising two input and two output wires for fan-in and fan-out. This makes it respectively three and five orders of magnitude more energy-efficient than complementary-metaloxidesemiconductor- transistor (CMOS)-based and spin-transfer-torque-driven nanomagnet-based NAND gates. Finally, we show that the dissipation in the external clocking circuit can always be reduced asymptotically to zero using increasingly slow adiabatic clocking, such as by designing the RC time constant to be three orders of magnitude smaller than the clocking period. However, the internal dissipation in the device must remain and cannot be eliminated if we want to perform fault-tolerant classical computing. © 2012 IOP Publishing Ltd.","","Dynamics; Energy dissipation; Magnets; Nanomagnetics; Wire; Electrostatic potentials; Energy efficient; Fan-out; Fault-tolerant; Four-phase clocking; Gate operation; Internal dissipation; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetostrictive layers; Multiferroics; NAND gate; Orders of magnitude; Piezoelectric layers; RC time constants; Single gates; Switching dynamics; Thermal fluctuations; Three orders of magnitude; Throughput rate; Throughput","","","","","","","ITRS Report CORE9GPLL-HCMOS9-TEC-4.0 Databook, (2003); Salahuddin S., Datta S., Appl. Phys. Lett., 90, (2007); Ney A., Pampuch C., Koch R., Ploog K.H., Nature, 425, (2003); Cowburn R.P., Welland M.E., Science, 287, (2000); Casba G., Imre A., Bernstein G.H., Porod W., Metlushko V., IEEE Trans. Nanotechnol., 1, (2002); Bandyopadhyay S., Das B., Miller A.E., Nanotechnology, 5, (1994); Alam M.T., Siddiq M.J., Bernstein G.H., Niemier M., Porod W., Hu X.S., IEEE Trans. Nanotechnol., 9, (2010); Ralph D.C., Stiles M.D., J. Magn. Magn. Mater., 320, (2008); Yamanouchi M., Chiba D., Matsukura F., Ohno H., Nature, 428, (2004); Bandyopadhyay S., Cahay M., Nanotechnology, 20, (2009); Roy K., Bandyopadhyay S., Atulasimha J., Phys. Rev. B, 83, (2011); Fukami S., Et al., Symp. on VLSI Technology, Symposium on VLSI Technology, Digest of Technical Papers, pp. 230-231, (2009); Atulasimha J., Bandyopadhyay S., Appl. Phys. Lett., 97, (2010); Roy K., Bandyopadhyay S., Atulasimha J., Appl. Phys. Lett., 99, (2011); Salehi Fashami M., Roy K., Atulasimha J., Bandyopadhyay S., Nanotechnology, 22, (2011); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. 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Phys., 21, (1982); Allwood D.A., Xiong G., Faulkner C.C., Atkinson D., Petit D., Cowburn R.P., Science, 309, (2005); Xia P.X.K., Gu C., Tang L., Yang H., Li J., Nature Nanotechnol., 3, (2008); Fredkin E., Toffoli T., Int. J. Theor. Phys., 21, (1982); Dsouza N., Atulasimha J., Bandyopadhyay S., J. Phys. D: Appl. Phys., 44, (2011); Pertsev N.A., Kohlstedt H., Appl. Phys. Lett., 95, (2009); Dsouza N., Atulasimha J., Bandyopadhyay S., An Ultrafast Image Recovery and Recognition System Implemented with Nanomagnets Possessing Biaxial Magnetocrystalline Anisotropy, (2011)","","","","","","","","","13616528","","NNOTE","","English","Nanotechnology","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-84857611617" +"Krivoruchko V.N.","Krivoruchko, V.N. (55406187000)","55406187000","Spin waves damping in nanometre-scale magnetic materials (Review Article)","2015","Low Temperature Physics","41","9","","670","681","11","10","10.1063/1.4930970","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84943139789&doi=10.1063%2f1.4930970&partnerID=40&md5=658ca2016f4a427147558619c548fe80","Donetsk Institute for Physics and Engineering, The National Academy of Sciences of Ukraine, 46 Nauki Ave., Kyiv, 03680, Ukraine","Krivoruchko V.N., Donetsk Institute for Physics and Engineering, The National Academy of Sciences of Ukraine, 46 Nauki Ave., Kyiv, 03680, Ukraine","Spin dynamics in magnetic nanostructured materials is a topic of great current interest. To describe spin motions in such magnetic systems, the phenomenological Landau-Lifshitz (LL), or the LL-Gilbert (LLG), equation is widely used. Damping term is one of the dominant features of magnetization dynamics and plays an essential role in these equations of motion. The form of this term is simple; however, an important question arises whether it provides a proper description of the magnetization coupling to the thermal bath and the related magnetic fluctuations in the real nanometre-scale magnetic materials. It is now generally accepted that for nanostructured systems the damping term in the LL (LLG) equation fails to account for the systematics of the magnetization relaxation, even at the linear response level. In ultrathin films and nanostructured magnets particular relaxation mechanisms arise, extrinsic and intrinsic, which are relevant at nanometre-length scales, yet are not so efficient in bulk materials. These mechanisms of relaxation are crucial for understanding the magnetization dynamics that results in a linewidth dependence on the nanomagnet's size. We give an overview of recent efforts regarding the description of spin waves damping in nanostructured magnetic materials. Three types of systems are reviewed: ultrathin and exchange-based films, magnetic nanometre-scale samples and patterned magnetic structures. The former is an example of a rare case where consideration can be done analytically on microscopic footing. The latter two are typical samples when analytical approaches hardly have to be developed and numerical calculations are more fruitful. Progress in simulations of magnetization dynamics in nanometre-scale magnets gives hopes that a phenomenological approach can provide us with a realistic description of spin motions in expanding diverse of magnetic nanostructures. © 2015 AIP Publishing LLC.","","Damping; Equations of motion; Magnetic structure; Magnets; Multilayers; Nanostructured materials; Nanostructures; Spin dynamics; Spin waves; Ultrathin films; Magnetic nanostructures; Magnetization dynamics; Magnetization relaxation; Nanostructured magnetic materials; Nanostructured magnets; Nanostructured systems; Patterned magnetic structure; Phenomenological approach; Magnetization","","","","","Horizon 2020 Framework Programme, H2020, (644348)","","Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., Phys. Rev, 100, (1955); Gilbert T.L., Kelly J.M., Conference on Magnetism and Magnetic Materials, (1955); Callen H.B., J. Phys. Chem. Solids, 4, (1958); Bar'yakhtar V.G., Sov. Phys. 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Lett, 105, (2010); Martyanov O.N., Yudanov V.F., Lee R.N., Nepijko S.A., Elmers H.J., Hentel R., Schneider C.M., Schonhense G., Phys. Rev. B, 75, (2007); Vovk A., Golub V., Malkinski L., Krivoruchko V.N., Marchenko A.I., J. Appl. Phys, 117, (2015); Neusser S., Botters B., Grundler D., Phys. Rev. B, 78, (2008); Kim S.-K., J. Phys. D: Appl. Phys, 43, (2010); Liu T., Chang H., Vlaminck V., Sun Y., Kabatek M., Hoffmann A., Deng L., Wu M., J. Appl. Phys, 115, (2014); Hahn C., Naletov V.V., de Loubens G., Klein O., d'Allivy Kelly O., Anane A., Bernard R., Jacquet E., Bortolotti P., Cros V., Prieto J.L., Munoz M., Appl. Phys. Lett, 104, (2014); Pirro P., Bracher T., Chumak A.V., Lagel B., Dubs C., Surzhenko O., Gornert P., Leven B., Hillebrands B., Appl. Phys. Lett, 104, (2014); Haiming Y., d'Allivy Kelly O., Cros V., Bernard R., Bortolotti P., Anane A., Brandl F., Huber R., Stasinopoulos I., Grundler D., Sci. Rep, 4, (2014)","V.N. Krivoruchko; Donetsk Institute for Physics and Engineering, The National Academy of Sciences of Ukraine, Kyiv, 46 Nauki Ave., 03680, Ukraine; email: krivoruc@gmail.com","","American Institute of Physics Inc.","","","","","","1063777X","","","","English","Low Temp. Phys","Review","Final","","Scopus","2-s2.0-84943139789" +"Zhang Y.; Song Z.; Dong F.","Zhang, Yun (56035973600); Song, Zhenghua (55204312300); Dong, Faxin (7102148949)","56035973600; 55204312300; 7102148949","Study on the luminescence behavior of lanthanide ions using luminol as probe","2012","Journal of Luminescence","132","9","","2462","2467","5","8","10.1016/j.jlumin.2012.04.012","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861008460&doi=10.1016%2fj.jlumin.2012.04.012&partnerID=40&md5=33b843751525db7fd0b696aaec2cf5ac","Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Ministry of Education, Xian 710069, China","Zhang Y., Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Ministry of Education, Xian 710069, China; Song Z., Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Ministry of Education, Xian 710069, China; Dong F., Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Ministry of Education, Xian 710069, China","Using luminol as the probe, the luminescence behavior of trivalent lanthanide ions (Ln 3=La 3, Ce 3, Pr 3, Nd 3, Sm 3, Eu 3, Gd 3, Tb 3, Dy 3, Ho 3, Er 3, Tm 3, Yb 3 and Lu 3) in aqueous solution was first investigated by fluorescence, and the sensitivity enhanced by 3-5 orders of magnitude compared with the Ln 3 intrinsic fluorescence. It was found that Ln 3 with luminol could form a 1:1 association complex which remarkably enhanced the fluorescence signal of luminol. The increment of fluorescence intensity was proportional to the concentration of Ln 3 in the range of 1.0-70.0 nmol L -1, and the linear correlation equation, ΔI F=AC LnB, was given. The relationships of A (defined as sensitivity factor) with some physical parameters (atomic number Z, ionic radius γ ±, standard redox potential E o and hydration enthalpy ΔH hyd) were discussed. The good symmetry of A vs. Z plot for light lanthanides (LLG) and the heavy lanthanides (HLG) and linear relations of A with Z, γ ±, E o and ΔH hyd should originate in the special features of Ln 3 electronic configurations [Xe]4f n (n=0-14). Using the proposed model of Ln 3-luminol interaction, lg[ΔI F/(I Fo-ΔI F)]=rlg[Ln]lg k, the association constant k was obtained over the range of 1.95×10 6-2. 63×10 7 L mol -1. © 2012 Elsevier B.V. All rights reserved.","Lanthanide ions; Luminescence behavior; Luminol; Modeling","Association reactions; Atoms; Cerium; Erbium; Europium; Fluorescence; Gadolinium; Ions; Models; Probes; Redox reactions; Xenon; Ytterbium; Association constant; Atomic numbers; Electronic configuration; Fluorescence intensities; Fluorescence signals; Hydration enthalpy; Intrinsic fluorescence; Ionic radius; Lanthanide ion; Linear correlation; Linear relation; Luminols; Orders of magnitude; Physical parameters; Redox potentials; Sensitivity factors; Trivalent lanthanide ions; Holmium","","","","","NWU Graduate Innovation and Creativity Funds, (07JK395, 09YSY18, 09YZZ45, 10YZZ29, 2006B05); Ministry of Education, MOE; Natural Science Foundation of Shaanxi Province","The authors gratefully acknowledge the financial support from Shaanxi Province Nature Science Foundation, the Foundation of Ministry of Education and the NWU Graduate Innovation and Creativity Funds, China , Grant nos. 2006B05 , 07JK395 , 09YZZ45 , 10YZZ29 and 09YSY18 .","Connelly N.G., Damhus T., Hartshorn R.M., Hutton A.T., Nomenclature of Inorganic Chemistry: IUPAC Recommendations, (2005); Moore E.G., Samuel A.P.S., Raymond K.N., Acc. 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Soc., 89, (1967); Westrum Jr.E.F., Lanthanide and Actinide Chemistry, (1967); Sinha S.P., Struct. Bond., 30, (1976); Fidelis L., Siekierskg S., J. Inorg. Nucl. Chem., 29, (1967); Johnson D.A., Inorganic Chemistry in Focus III, (2006); Masuda A., Nature, 212, (1966); Noddack W., Brukl A., Angew. Chem., 50, (1937); Shannon R.D., Acta Crystallogr. A, 32, (1976); Bagus P.S., Lee Y.S., Pitzer K.S., Chem. Phys. Lett., 33, (1975)","Z. Song; Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, Northwest University, Ministry of Education, Xian 710069, China; email: songzhenghua@hotmail.com","","","","","","","","00222313","","JLUMA","","English","J Lumin","Article","Final","","Scopus","2-s2.0-84861008460" +"Scholz W.; Crawford T.M.; Parker G.J.; Clinton T.W.; Ambrose T.; Kaka S.; Batra S.","Scholz, Werner (7102228903); Crawford, T.M. (7102138487); Parker, Gregory J. (7402344444); Clinton, T.W. (7004133254); Ambrose, T. (7003401995); Kaka, Shehzaad (6602167256); Batra, Sharat (7202128856)","7102228903; 7102138487; 7402344444; 7004133254; 7003401995; 6602167256; 7202128856","Fast magnetization switching with circularly polarized fields and short pulses","2008","IEEE Transactions on Magnetics","44","11 PART 2","","3134","3136","2","0","10.1109/TMAG.2008.2001600","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85130081559&doi=10.1109%2fTMAG.2008.2001600&partnerID=40&md5=9aaae3a1eabdbf987990cba91af0d3f9","Seagate Technology, Pittsburgh, PA 15222, United States; USC Nanocenter, University of South Carolina, Columbia, SC 29208, United States; GE Global Research, Niskayuna, NY 12309, United States","Scholz W., Seagate Technology, Pittsburgh, PA 15222, United States; Crawford T.M., USC Nanocenter, University of South Carolina, Columbia, SC 29208, United States; Parker G.J., GE Global Research, Niskayuna, NY 12309, United States; Clinton T.W., Seagate Technology, Pittsburgh, PA 15222, United States; Ambrose T., Seagate Technology, Pittsburgh, PA 15222, United States; Kaka S., Seagate Technology, Pittsburgh, PA 15222, United States; Batra S., Seagate Technology, Pittsburgh, PA 15222, United States","In this paper, we study the magnetization reversal process of single-domain Stoner-Wohlfarth particles subject to circularly polarized fields and short pulses using analytical and numerical models. We investigate the effect of short unipolar, bipolar field, and circularly polarized field pulses, which are applied perpendicular to the uniaxial magnetocrystalline anisotropy axis, on the magnetization switching dynamics. © 2008 IEEE.","Fast switching; Landau-lifshitz-gilbert (LLG) equation; Magnetization reversal","Circular polarization; Laser radiation; Magnetocrystalline anisotropy; Analytical and numerical models; Circularly polarized; Fast magnetization; Fast switching; Landau-Lifshitz-Gilbert equations; Magnetization reversal process; Magnetization switching; Stoner-Wohlfarth particle; Magnetization reversal","","","","","","","He L., Doyle W.D., Fujiwara H., High speed coherent switching below the Stoner-Wohlfarth limit, IEEE Trans. Magn., 30, 1-6 PART, pp. 4086-4088, (1994); Suess D., Schrefl T., Scholz W., Fidler J., Fast switching of small magnetic particles, J. Magn. Magn. Mater., 242-245, pp. 426-429, (2002); Sun Z.Z., Wang X.R., Theoretical limit of the minimal magnetization switching field and the optimal field pulse for stoner particles, Phys. Rev. Lett., 97, (2006); Kaka S., Russek S., Switching in spin-valve devices in response to subnanosecond longitudinal field pulses, J. Appl. Phys., 87, 9, pp. 6391-6393, (2000); Gerrits Th., Hohlfeld J., Gielkens O., Veenstra K.J., Bal K., Rasing Th., Van Den Berg H.A.M., Magnetization dynamics in NiFe thin films induced by short in-plane magnetic field pulses, Journal of Applied Physics, 89, 11, pp. 7648-7650, (2001); Tudosa I., Stamm C., Kashuba A.B., King F., Siegmann H.C., Stoehr J., Ju G., Lu B., Weller D., The ultimate speed of magnetic switching in granular recording media, Nature, 428, pp. 831-833, (2004)","W. Scholz; Seagate Technology, Pittsburgh, PA 15222, United States; email: werner.scholz@seagate.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85130081559" +"Chen W.; Han M.; Deng L.","Chen, Wenbing (56092812000); Han, Mangui (15759475100); Deng, Longjiang (15070111700)","56092812000; 15759475100; 15070111700","Microwave absorption properties of cobalt nanowires fabricated by pulse electrodeposition","2010","Progress in Electromagnetics Research Symposium","2","","","1718","1722","4","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84898807431&partnerID=40&md5=e6a151ae146ef0091b9086d437bd312a","State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Science and Technology of China, Chengdu 610054, China","Chen W., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Science and Technology of China, Chengdu 610054, China; Han M., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Science and Technology of China, Chengdu 610054, China; Deng L., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Science and Technology of China, Chengdu 610054, China","In this work, cobalt nanowires with a preferred growth orientation have been fabricated by a pulse electrodeposition method. The imaginary part of the permeability spectra for the nanowire/paraffin composite samples exhibit a strong absorption peak at 6.1 GHz and two minor peaks at above 10GHz. It is determined that the peak at 6.1 GHz is attributed to the natural resonance mechanism and the other two peaks are caused by eddy current effect. We have fitted the permeability spectra attributed to natural resonance using the LLG equation. Calculation based on the Kittel equation substantiates our explanation. The electromagnetic wave reflection loss values of the nanowire/paraffin composite indicate that cobalt nanowires composites can be used for microwave absorption.","","Electrodeposition; Nanowires; Composite samples; Eddy-current effects; Microwave absorption; Microwave absorption properties; Natural resonance; Permeability spectrum; Pulse electrodeposition; Strong absorptions; Cobalt","","","","","National Natural Science Foundation of China, (60701016)","","Han M., Deng L., Appl. Phys. Lett., 90, (2007); Han M., Ou Y., Liang D., Deng L., Chin. Phy. B, 18, (2009); Liu Q., Zhang D., Appl. Phys. Lett., 93, (2008); Dong X.L., Zhang X.F., Huang H., Appl. Phys. Lett., 92, (2008); Encinas A., Vila L., Darques M., George J.M., Piraux L., Nanotechnology, 18, (2007); Gao B., Liu Q.F., Li F.S., Feng J., Xue D.S., J. Phys. D: Appl. Phys., 41, (2008); Zhang J., Jones G.A., Donnelly S.E., Li G.H., J. Appl. Phys., 101, (2007); Ursache A., Goldbach J.T., Russell T.P., Tuominen M.T., J. Appl. Phys., 97, (2005); Han X.H., Liu Q.F., Ren Y., Liu R.L., Li F.S., J. Phys. D: Appl. Phys., 42, (2009); Li D.D., Thompson R.S., Bergmann G., Lu J.G., Adv. Mater., 20, (2008); Qunadjela K., Ferre R., Maurice J.L., Piraux L., Dubois S., J. Appl. Phys., 81, (1997); Li F.S., Wang T., Ren L.Y., Sun J.R., J. Phys.: Condens. Matter, 16, (2004); Encinas-Oropesa A., Demand M., Piraux L., Phys. Rev. B, 63, (2001); Fang J.X., Yin Z.W., Physics of Dielectric Materials, (2000); Liao S.B., Ferromagnetism, 6, (1998); Wu M.Z., Zhang Y.D., Hui S., Xiao T.D., Appl. Phys. Lett., 80, (2002); Goglio G., Pignard S., Radulescu A., Piraux L., Appl. Phys. Lett., 75, (1999); Kittel C., Phys. Rev., 73, (1948)","","","Electromagnetics Academy","MIT Cent. Electromagn. Theory Appl./Res. Lab. Electron.; National Key Laboratory of Space Microwave Technology; Northwestern Polytechnical University; The Electromagnetics Academy; The Electromagnetics Academy at Zhejiang University; Zhejiang University","Progress in Electromagnetics Research Symposium 2010, PIERS 2010 Xi'an","22 March 2010 through 26 March 2010","Xi'an","104507","15599450","978-161782778-5","","","English","Prog. Electromagn. Res. Symp.","Conference paper","Final","","Scopus","2-s2.0-84898807431" +"d'Aquino M.; Serpico C.; Miano G.; Forestiere C.","d'Aquino, Massimiliano (9732823500); Serpico, Claudio (23013514800); Miano, Giovanni (7006758103); Forestiere, Carlo (26032511200)","9732823500; 23013514800; 7006758103; 26032511200","A novel formulation for the numerical computation of magnetization modes in complex micromagnetic systems","2009","Journal of Computational Physics","228","17","","6130","6149","19","46","10.1016/j.jcp.2009.05.026","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-67650140647&doi=10.1016%2fj.jcp.2009.05.026&partnerID=40&md5=c50999fd76055ec66fdec81fb2173995","Department of Technology, University of Napoli Parthenope, Centro Direzionale di Napoli, I-80143, Isola C4, Italy; Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy","d'Aquino M., Department of Technology, University of Napoli Parthenope, Centro Direzionale di Napoli, I-80143, Isola C4, Italy; Serpico C., Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; Miano G., Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; Forestiere C., Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy","The small oscillation modes in complex micromagnetic systems around an equilibrium are numerically evaluated in the frequency domain by using a novel formulation, which naturally preserves the main physical properties of the problem. The Landau-Lifshitz-Gilbert (LLG) equation, which describes magnetization dynamics, is linearized around a stable equilibrium configuration and the stability of micromagnetic equilibria is discussed. Special attention is paid to take into account the property of conservation of magnetization magnitude in the continuum as well as discrete model. The linear equation is recast in the frequency domain as a generalized eigenvalue problem for suitable self-adjoint operators connected to the micromagnetic effective field. This allows one to determine the normal oscillation modes and natural frequencies circumventing the difficulties arising in time-domain analysis. The generalized eigenvalue problem may be conveniently discretized by finite difference or finite element methods depending on the geometry of the magnetic system. The spectral properties of the eigenvalue problem are derived in the lossless limit. Perturbation analysis is developed in order to compute the changes in the natural frequencies and oscillation modes arising from the dissipative effects. It is shown that the discrete approximation of the eigenvalue problem obtained either by finite difference or finite element methods has a structure which preserves relevant properties of the continuum formulation. Finally, the generalized eigenvalue problem is solved for a rectangular magnetic thin-film by using the finite differences and for a linear chain of magnetic nanospheres by using the finite elements. The natural frequencies and the spatial distribution of the natural modes are numerically computed. © 2009 Elsevier Inc. All rights reserved.","Finite difference and finite element micromagnetics; Generalized eigenvalue problem; Landau-Lifshitz-Gilbert equation; Micromagnetics; Oscillation modes","Continuum mechanics; Eigenvalues and eigenfunctions; Finite element method; Frequency domain analysis; Magnetic fields; Magnetization; Nanospheres; Thin films; Time domain analysis; Eigenvalue problem; Finite difference and finite element micromagnetic; Frequency domains; Generalized eigenvalue problems; Landau-Lifshitz-Gilbert equations; Micromagnetic systems; Micromagnetics; Oscillation mode; Property; Natural frequencies","","","","","","","Suhl H., Proc. IRE, 44, (1956); Suhl H., J. Phys. Chem. Solids, 1, (1957); Suhl H., Zhang X.Y., Phys. Rev. Lett., 57, (1986); McMichael R.D., Wigen P.E., Phys. Rev. Lett., 64, (1990); Bertotti G., Et al., Phys. Rev. Lett., 87, (2001); d'Aquino M., Et al., IEEE Trans. Magn., 42, (2006); Perzlmeier K., Et al., Phys. Rev. Lett., 94, (2005); Bolte M., Et al., Phys. Rev. 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Phys., 209, (2005); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Lang S., Differential and Riemannian Manifolds, (1995); Science of Hysteresis, (2005); Kantorovich L.V., Akilov G.P., Functional Analysis, (1982); Fidler J., Schrefl T., J. Phys. D: Appl. Phys., 33, (2000); Chetaev N.G., The Stability of Motion (Eng. Trans.), (1961); Michel A.N., Hou L., Liu D., Stability of Dynamical Systems, (2008); Massera J.L., Ann. Math., 64, (1956); Weinberger H.F., Variational methods for eigenvalue approximation, (1974); Kato T., Perturbation Theory for Linear Operators, (1980); Rave W., Ramstock K., Hubert A., J. Magn. Magn. Mater., 183, (1998); Schabes M.E., Et al., IEEE Trans. Magn., 23, (1987); Lehoucq R.B., Et al., ARPACK Users' Guide: Solution of Large-Scale Eigenvalue Problems with Implicitly Restarted Arnoldi Methods, (1998); Anderson E., Et al., LAPACK User's Guide, (1999); Guslienko K.Yu., Et al., Phys. Rev. Lett., 96, (2006); Graglia R.D., IEEE Trans. Ant. Prop., 41, (1993); Di Fratta G., Serpico C., d'Aquino M., Phys. B, 403, (2008)","M. d'Aquino; Department of Technology, University of Napoli Parthenope, Centro Direzionale di Napoli, I-80143, Isola C4, Italy; email: mdaquino@unina.it","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","","Scopus","2-s2.0-67650140647" +"Yokoyama T.; Zang J.; Nagaosa N.","Yokoyama, Takehito (35466038500); Zang, Jiadong (16837552300); Nagaosa, Naoto (7006133395)","35466038500; 16837552300; 7006133395","Theoretical study of the dynamics of magnetization on the topological surface","2010","Physical Review B - Condensed Matter and Materials Physics","81","24","241410","","","","149","10.1103/PhysRevB.81.241410","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77955582486&doi=10.1103%2fPhysRevB.81.241410&partnerID=40&md5=40ac4a3562bc9c92ea7075f70a6da427","Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan; Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan; Department of Physics, Fudan University, Shanghai 200433, China; Cross-Correlated Materials Research Group (CMRG), Correlated Electron Research Group (CERG), RIKEN-ASI, Wako 351-0198, Japan","Yokoyama T., Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan; Zang J., Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan, Department of Physics, Fudan University, Shanghai 200433, China; Nagaosa N., Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan, Cross-Correlated Materials Research Group (CMRG), Correlated Electron Research Group (CERG), RIKEN-ASI, Wako 351-0198, Japan","We investigate theoretically the dynamics of magnetization coupled to the surface Dirac fermions of a three-dimensional topological insulator by deriving the Landau-Lifshitz-Gilbert (LLG) equation in the presence of charge current. Both the inverse spin-galvanic effect and the Gilbert damping coefficient α are related to the two-dimensional diagonal conductivity σxx of the Dirac fermion, while the Berry phase of the ferromagnetic moment to the Hall conductivity σxy. The spin-transfer torque and the so-called β terms are shown to be negligibly small. Anomalous behaviors in various phenomena including the ferromagnetic resonance are predicted in terms of this LLG equation. © 2010 The American Physical Society.","","","","","","","","","Qi X.L., Zhang S.C., Phys. Today, 63, 1, (2010); Hasan M., Kane C.; Qi X.-L., Hughes T.L., Zhang S.-C., Phys. Rev. B, 78, (2008); Yokoyama T., Tanaka Y., Nagaosa N., Phys. Rev. Lett., 102, (2009); Liu Q., Liu C.-X., Xu C., Qi X.-L., Zhang S.-C., Phys. Rev. Lett., 102, (2009); Yokoyama T., Tanaka Y., Nagaosa N., Phys. Rev. B, 81, (2010); Fu L., Kane C.L., Phys. Rev. Lett., 100, (2008); Tanaka Y., Yokoyama T., Nagaosa N., Phys. Rev. Lett., 103, (2009); Linder J., Tanaka Y., Yokoyama T., Sudbo A., Nagaosa N., Phys. Rev. Lett., 104, (2010); Garate I., Franz M., Phys. Rev. Lett., 104, (2010); Manchon A., Zhang S., Phys. Rev. B, 78, (2008); Chernyshov A., Et al., Nat. Phys., 5, (2009); Miron I.M., Et al., Nature Mater., 9, (2010); Kohno H., Tatara G., Shibata J., J. Phys. Soc. Jpn., 75, (2006); Tserkovnyak Y., Skadsem H.J., Brataas A., Bauer G.E.W., Phys. Rev. B, 74, (2006); Tserkovnyak Y., Brataas A., Bauer G.E., J. Magn. Magn. Mater., 320, (2008); Tserkovnyak Y., Fiete G.A., Halperin B.I., Appl. Phys. Lett., 84, (2004); Wong C.H., Tserkovnyak Y., Phys. Rev. B, 80, (2009); Zhang S., Zhang S.S.-L., Phys. Rev. Lett., 102, (2009); Zang J., Nagaosa N.","","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-77955582486" +"Murugesh S.; Lakshmanan M.","Murugesh, S. (6507802344); Lakshmanan, M. (7006704351)","6507802344; 7006704351","Bifurcation and chaos in spin-valve pillars in a periodic applied magnetic field","2009","Chaos","19","4","043111","","","","17","10.1063/1.3258365","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-74349107911&doi=10.1063%2f1.3258365&partnerID=40&md5=063323d8cc2bbc4015797442d752ab93","Department of Physics and Meteorology, IIT-Kharagpur, Kharagpur 721302, India; Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620024, India","Murugesh S., Department of Physics and Meteorology, IIT-Kharagpur, Kharagpur 721302, India; Lakshmanan M., Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620024, India","We study the bifurcation and chaos scenario of the macromagnetization vector in a homogeneous nanoscale-ferromagnetic thin film of the type used in spin-valve pillars. The underlying dynamics is described by a generalized Landau-Lifshitz-Gilbert (LLG) equation. The LLG equation has an especially appealing form under a complex stereographic projection, wherein the qualitative equivalence of an applied field and a spin-current induced torque is transparent. Recently, chaotic behavior of such a spin vector has been identified by Li [Li Phys. Rev. B 74, 054417 (2006)] using a spin-polarized current passing through the pillar of constant polarization direction and periodically varying magnitude, owing to the spin-transfer torque effect. In this paper, we show that the same dynamical behavior can be achieved using a periodically varying applied magnetic field in the presence of a constant dc magnetic field and constant spin current, which is technically much more feasible, and demonstrate numerically the chaotic dynamics in the system for an infinitely thin film. Further, it is noted that in the presence of a nonzero crystal anisotropy field, chaotic dynamics occurs at much lower magnitudes of the spin current and dc applied field. © 2009 American Institute of Physics.","","Algorithms; Computer Simulation; Electromagnetic Fields; Nonlinear Dynamics; Oscillometry; Signal Processing, Computer-Assisted; algorithm; article; computer simulation; electromagnetic field; methodology; nonlinear system; oscillometry; signal processing","","","","","DST-IRHPA; DST-Ramanna; Department of Science and Technology, Ministry of Science and Technology, India, DST"," S.M. wishes to thank DST, India, for funding through the FASTTRACK scheme. The work of M.L. forms part of a DST-IRHPA research project and is supported by a DST-Ramanna fellowship. ","Wolf S.A., Chtchelkanova A.Y., Treger D.M., IBM J. Res. Dev., 50, (2006); Nesbet R.K., IBM J. Res. Dev., 42, (1998); Tsang C.H., Fontana Jr. R.E., Lin T., Heim D.E., Gurnet B.A., Williams M.L., IBM J. Res. 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Phys., 85, (1999); De Aguiar F.M., Azevedo A., Rezende S.M., Nonlinear dynamics of spin-injected magnons in magnetic nanostructures, Journal of Applied Physics, 91, 3-10, (2002); Murugesh S., Lakshmanan M., Chaos, Solitons Fractals, 41, (2009); Kosaka C., Nakamura K., Murugesh S., Lakshmanan M., Physica D, 203, (2005); Lakshmanan M., Nakamura K., Phys. Rev. Lett., 53, (1984)","S. Murugesh; Department of Physics and Meteorology, IIT-Kharagpur, Kharagpur 721302, India; email: murugesh@phy.iitkgp.ernet.in","","American Institute of Physics Inc.","","","","","","10541500","","","20059207","English","Chaos","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-74349107911" +"Chen J.; Zhang B.; Tang D.; Yang Y.; Xu W.; Lu H.","Chen, Jiangwei (7501885251); Zhang, Baoshan (7406903849); Tang, Dongming (13003495300); Yang, Yi (57192550904); Xu, Weidong (59444942300); Lu, Huaixian (7404843760)","7501885251; 7406903849; 13003495300; 57192550904; 59444942300; 7404843760","Possible existence of a new type of left-handed materials in coupled ferromagnetic bilayer films","2006","Journal of Magnetism and Magnetic Materials","302","2","","368","374","6","12","10.1016/j.jmmm.2005.09.040","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33645865884&doi=10.1016%2fj.jmmm.2005.09.040&partnerID=40&md5=42cb477c99531ee9e7dfb5a28b0df0f6","National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; Nanjing Artillery Academy, Nanjing, 211132, China; Engineering Institute of Engineer Corps., PLA University of Science and Technology, Nanjing, 210007, China","Chen J., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China, Nanjing Artillery Academy, Nanjing, 211132, China; Zhang B., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; Tang D., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; Yang Y., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; Xu W., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China, Engineering Institute of Engineer Corps., PLA University of Science and Technology, Nanjing, 210007, China; Lu H., National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China","On the basis of Landau-Lifshitz-Gilbert (LLG) equation, an anomalous ferromagnetic resonance behavior is demonstrated in detail. Coupling between the magnetic moments produces a 3π/2 phase delay for one of the moments ferromagnetic resonance unusually, thus leads the sign of magnetic susceptibility over(χ, ̃) = χ′ - j χ″ to be opposite to that induced by the usual ferromagnetic resonance. Consequently, a left-handed material (LHM) may be formed near the low-frequency side of the resonance. Particularly, a LHM with negative value of real part of permeability only is predicted. © 2005 Elsevier B.V. All rights reserved.","Ferromagnetic resonance; Left-handed material","Ferromagnetic resonance; Magnetic couplings; Magnetic materials; Magnetic moments; Magnetic permeability; Magnetic susceptibility; Bilayer films; Landau-Lifshitz-Gilbert (LLG); Left-handed material (LHM); Low-frequency side; Magnetic films","","","","","Postdoctoral Support Program in Scientific Research of Jiangsu Province, (0204003409)","J. Chen acknowledges support in this work from the Postdoctoral Support Program in Scientific Research of Jiangsu Province, No. 0204003409.","Veselago V.G., Sov. Phys. Usp., 10, (1968); Pendry J.B., Holden A.J., Stewart W.J., Youngs I., Phys. Rev. Lett., 76, (1996); Pendry J.B., Holden A.J., Robbins D.J., Stewart W.J., IEEE Trans. Microwave Theory Technol., 47, (1999); Smith D.R., Padilla W.J., Vier D.C., Nemat-Nasser S.C., Schultz S., Phys. Rev. Lett., 84, (2000); Shelby R.A., Smith D.R., Schultz S., Science, 296, (2001); Valanju P.M., Walser R.M., Valanju A.P., Phys. Rev. Lett., 88, (2002); Koschny T., Kafesaki M., Economou E.N., Soukoulis C.M., Phys. Rev. Lett., 93, (2004); Chui S.T., Hu L.B., Phys. Rev. B, 65, (2002); Tomita S., Hagiwara M., Kashiwagi T., Tsuruta C., Matsui Y., Fujii M., Hayashi S., J. Appl. Phys., 95, (2004); Wu R.X., Zhang X.K., Lin Z.F., Chui S.T., Xiao J.Q., J. Magn. Magn. Mater., 271, (2004); Wu R.X., J. Appl. Phys., 97, (2005); Lakhtakia A., Krowne C.M., Optik, 114, (2003); Huang Y.Y., Gao L., Phys. Lett. A, 318, (2003); Huang Y.Y., Gao L., Phys. Lett. A, 328, (2004); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Gomez J., Butera A., Barnard J.A., Phys. Rev. B, 70, (2004); Heinrich B., Purcell S.T., Dutcher J.R., Urquhart K.B., Cochran J.F., Arrott A.S., Phys. Rev. B, 38, (1988); Zhang Z., Zhou L., Wigen P.E., Ounadjela K., Phys. Rev. B, 50, (1994); Vukadinovic N., Vacus O., Labrune M., Acher O., Pain D., Phys. Rev. Lett., 85, (2000); Vukadinovic N., Labrune M., Ben Youssef J., Marty A., Toussaint J.C., Le Gall H., Phys. Rev. B, 65, (2001); Gilbert T.L., Phys. Rev., 100, (1955); Landau L.D., Lifshitz E.M., Pitaevski L.P., Statistical Physics. third ed., part 2, (1980); Zhang K.Q., Electromagnetic Theory for Microwaves and Optoelectronics, (1998)","J. Chen; National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing, 210093, China; email: jwchen_nju@sohu.com","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-33645865884" +"Taniguchi T.; Imamura H.","Taniguchi, T. (36180180300); Imamura, H. (57386086300)","36180180300; 57386086300","Critical current density of domain wall oscillation due to spin-transfer torque","2011","Journal of Physics: Conference Series","292","1","012007","","","","1","10.1088/1742-6596/292/1/012007","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79956141228&doi=10.1088%2f1742-6596%2f292%2f1%2f012007&partnerID=40&md5=f7729c9deceaf7528a4975c8821a1c30","Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, 1-1-1 Umezono, Japan; Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573, 1-1-1 Tennou-dai, Japan","Taniguchi T., Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, 1-1-1 Umezono, Japan, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573, 1-1-1 Tennou-dai, Japan; Imamura H., Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, 1-1-1 Umezono, Japan","The domain wall oscillation due to spin-transfer torque was studied by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation. For a domain wall whose rotation angle θmax is less than 180°, we found the existence of the critical current density above which the magnetization dynamics are induced. We studied the dependence of the critical current density on the rotation angle θmax and found that the critical current density is proportional to 180° - θmax.","","Current density; Magnetization; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Rotation angles; Spin transfer torque; Wall oscillations; Critical currents","","","","","","","Franchin M., Fischbacher T., Bordignon G., De Groot P., Fangohr H., Phys. Rev. B, 78, (2008); Matsushita K., Sato J., Imamura H., Sasaki M., J. Magn. Soc. Jpn., 34, (2010); Levy P.M., Zhang S., Phys. Rev. Lett., 79, (1997); Simanek E., Phys. Rev. B, 63, (2003); Matsushita K., Sato J., Imamura H., IEEE. Trans. Magn., 44, (2008); Sato J., Matsushi K., Imamura H., IEEE. Trans. Magn., 44, (2008); Matsushita K., Sato J., Imamura H., J. Appl. Phys., 105; Sato J., Matsushi K., Imamura H., J. Appl. Phys., 105; Taniguchi T., Imamura H., Phys. Rev. B, 81, (2010); Taniguchi T., Imamura H., Angle Dependence of the Magnetoresistance of CCP-CPP-GMR System, (2010); Takagishi M., Fuke H.N., Hashimoto S., Iwasaki H., Kawasaki S., Shinozaki R., Sahashi M., J. Appl. Phys., 105; Li Z., Zhang S., Phys. Rev. B, 70, (2004); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004)","T. Taniguchi; Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, 1-1-1 Umezono, Japan; email: tomohiro-taniguchi@aist.go.jp","","Institute of Physics Publishing","","","","","","17426588","","","","English","J. Phys. Conf. Ser.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-79956141228" +"Wadhwa P.; Jalil M.B.A.; Tan S.G.","Wadhwa, P. (8403188900); Jalil, M.B.A. (7006821429); Tan, S.G. (8571745900)","8403188900; 7006821429; 8571745900","Micromagnetic modeling with eddy current and current-induced spin torque effect","2005","Journal of Applied Physics","98","12","123902","","","","5","10.1063/1.2142077","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-29844444215&doi=10.1063%2f1.2142077&partnerID=40&md5=fdd62ad97db9cb2a9baa1e21446bcccc","Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore; Data Storage Institute, DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore","Wadhwa P., Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore; Jalil M.B.A., Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore; Tan S.G., Data Storage Institute, DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore","We present a micromagnetic model which incorporates eddy current and spin transfer torque effects due to the passage of a spin-polarized current in the current-perpendicular-to-plane (CPP) geometry. Eddy current effects are modeled by solving Faraday's and Poisson's equations self-consistently with the Landau-Lifshitz-Gilbert (LLG) equation, whereas spin transfer torque is modeled by including the Slonczewski spin torque term in the LLG equation. We consider a 50 nm cubic Co element, which forms the free layer of a pseudo-spin-valve structure. With a typical damping parameter of α=0.5, the eddy currents act to accelerate the magnetic reversal process. The spin torque effect can also assist the reversal process but at high current densities exceeding Jext = 108 A cm2 onwards. At these current densities, spin transfer torque also causes a substantial reduction in the coercivity. © 2005 American Institute of Physics.","","Cobalt; Coercive force; Current density; Damping; Eddy currents; Poisson equation; Polarization; Torque; Current-perpendicular-to-plane (CPP) geometry; Damping parameters; Micromagnetic modeling; Spin transfer torque; Magnetism","","","","","National University of Singapore, NUS, (R-263-000-329-112)","This work was supported by the National University of Singapore (NUS) Grant No. R-263-000-329-112. One of the authors (P. W.) thanks NUS for her research scholarship.","Jiang Y., Abe S., Ochiai T., Nozaki T., Hirohata A., Tezuka N., Inomata K., Phys. Rev. Lett., 92, (2004); Della T.E., Eicke J.G., IEEE Trans. Magn., 33, (1997); Torres L., Lopez-Diaz L., Martrinez E., Alejos O., IEEE Trans. Magn., 39, (2003); Sandler G.M., Bertram H.N., J. Appl. Phys., 81, (1997); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Lee K.-J., Deac A., Redon O., Nozieres J.-P., Dieny B., Nat. Mater., 3, (2004); Bozorth R.M., Ferromagnetism, (1993); Katine J.A., Albert F.J., Buhrman R.A., Phys. Rev. Lett., 84, (2000); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Albert F.J., Emley N.C., Myers E.B., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 89, (2002); Fert A., Cros V., George J.M., J. Magn. Magn. Mater., 272-276, (2004)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Review","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-29844444215" +"Guo J.; Jalil M.B.A.; Tan S.G.","Guo, Jie (55709457700); Jalil, Mansoor Bin Abdul (7006821429); Tan, Seng Ghee (8571745900)","55709457700; 7006821429; 8571745900","Self-consistent model of spin transfer switching of magnetic multilayers","2010","IEEE Transactions on Magnetics","46","6","5467550","1691","1694","3","0","10.1109/TMAG.2010.2045107","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77952799811&doi=10.1109%2fTMAG.2010.2045107&partnerID=40&md5=f6ba175ee64015779ef545063ca264b0","Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore; Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore; Data Storage Institute, A STAR (Agency for Science, Technology and Research), DSI Building, Singapore 117608, Singapore","Guo J., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore; Jalil M.B.A., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore, Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore; Tan S.G., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore, Data Storage Institute, A STAR (Agency for Science, Technology and Research), DSI Building, Singapore 117608, Singapore","The magnetization dynamics in a magnetic memory device has been analyzed self-consistently which takes into consideration the effects of the spin transfer torque. The coupled dynamics of the magnetic moment M and electron spins S are obtained by solving self-consistently the modified Landau-Lifshitz-Gilbert (LLG) equation governing M, and the dynamical equation of S, respectively. These equations incorporate the spin momentum transfer between M and S. The macrospin model is used, which assumes uniform magnetization in the free layer. We performed numerical simulations of the magnetization switching mechanism of M and the accompanying spin dynamics of S. The results indicate that besides the efficiency of the spin transfer torque, other factors such as the anisotropy field and the relaxation speed have a significant effect on the switching mechanism of the M. Our self-consistent model of the coupled magnetization and spin dynamics yields a more refined description of the current-induced switching process, which would be useful in achieving the optimal magnetization switching conditions in device applications. © 2006 IEEE.","Self-consistence; Spin transfer torque","Electrospinning; Magnetic moments; Magnetic storage; Magnetization; Spin dynamics; Switching; Current induced switching; Landau-Lifshitz-Gilbert equations; Magnetic memory devices; Magnetization switching; Magnetization switching mechanism; Self consistent modeling; Self-consistence; Spin transfer torque; Magnetic multilayers","","","","","","","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Rippard W.H., Pufall M.R., Kaka S., Russek S.E., Silva T.J., Phys. Rev. Lett., 92, (2004); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Seck M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, pp. 4281-4284, (1998); Yamaguchi A., Ono T., Nasu S., Miyake K., Mibu K., Shinjo T., Phys. Rev. Lett., 92, (2004); Togawa Y., Kimura T., Harada K., Akashi T., Matsuda T., Tonomura A., Otani Y., Jap. J. Appl. Phys., 45, (2006); Oezyilmaz B., Kent A.D., Monsma D., Sun J.Z., Rooks M.J., Koch R.H., Phys. Rev. Lett., 91, (2003); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, pp. 3149-3152, (2000); Albert F.J., Emley N.C., Myers E.B., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 89, (2002); Fuchs G.D., Emley N.C., Krivorotov I.N., Braganca P.M., Ryan E.M., Kiselev S.I., Sankey J.C., Ralph D.C., Buhrman R.A., Katine J.A., Appl. Phys. Lett., 85, pp. 1205-1207, (2004); Haney P.M., MacDonald A.H., Phys. Rev. Lett., 100, (2008); Moriya R., Hamaya K., Oiwa A., Munekata H., Jpn. J. Appl. Phys., PART II 43, (2004); Huai Y., Albert F., Nguyen P., Pakala M., Valet T., Appl. Phys. Lett., 84, pp. 3118-3120, (2004); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Shpiro A., Levy P.M., Zhang S., Phys. Rev. B, 67, (2003); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, pp. 3149-3152, (2000); Jalil M.B.A., Tan S.G., Phys. Rev. B, 72, (2005); Covington M., Science, 307, pp. 215-216, (2005); Mangin S., Ravelosona D., Katine J.A., Carey M.J., Terris B.D., Fullerton E.E., Nature Materials, 5, pp. 210-215, (2006); Krivorotov I.N., Emley N.C., Sankey J.C., Kiselev S.I., Ralph D.C., Buhrman R.A., Science, 307, pp. 228-231, (2005)","J. Guo; Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, Singapore; email: elegj@nus.edu.sg","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-77952799811" +"Hu R.L.; Soh A.K.","Hu, R.L. (13606954800); Soh, A.K. (7006795203)","13606954800; 7006795203","Micromagnetic simulation of size effects on the properties of ferromagnetic materials","2007","Key Engineering Materials","334-335 II","","","1125","1128","3","0","10.4028/0-87849-427-8.1125","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33847069217&doi=10.4028%2f0-87849-427-8.1125&partnerID=40&md5=38b0210c1cd0a4d2f6e5754edd266318","Department of Mechanical Engineering, University of Hong Kong, Hong Kong","Hu R.L., Department of Mechanical Engineering, University of Hong Kong, Hong Kong; Soh A.K., Department of Mechanical Engineering, University of Hong Kong, Hong Kong","Micromagnetic simulation was carried out to investigate the behavior of ferromagnetic materials at a very small length scale, at which the materials usually exhibit different properties compared with those of the corresponding bulk materials. By solving the time and spatial dependent Landau-Lifshitz- Gilbert (LLG) equation in reciprocal space using fast Fourier transformation (FFT) technique, the equilibrium magnetization state was, thus, achieved. The hysteresis loops were also simulated, from which the relation of coercivity and characteristic length was established. Besides, the effect of external stress on coercivity was also taken into consideration. The results showed that at such length scales the external stress strongly affected the magnetic behavior of ferromagnetic materials.","Coercivity; Ferromagnetic; Micromagnetic; Nanoparticle","Coercive force; Computer simulation; Fast Fourier transforms; Magnetic hysteresis; Hysteresis loops; Landau-Lifshitz- Gilbert (LLG) equations; Micromagnetic simulation; Ferromagnetic materials","","","","","","","Grancharov S.G., Zeng H., Sun S.H., Wang S.X., O'Brien S., Murray C.B., Kirtley J.R., Held G.A., J. Phys. Chem. B, 109, (2005); Arzt E., Acta. Mater, 46, (1998); Kneller E.F., Luborsky F.E., J. Appl. Phys, 34, (1963); Brown Jr. W.F., Phys. Rev, 130, (1963); Herzer G., IEEE Transactions on Magnetics, 26, (1990); Alben R., Becker J.J., Chi M.C., J. Appl. Phys, 49, (1978); Schrefl T., Fiedler J., Kronmuller H., Phys. Rev. B, 49, (1994); Fischer R., Schrefl T., Kronmuller H., Fidler J., J. Magn. Magn. Mater, 153, (1996); Weller D., Et al., IEEE Trans. Magn, 32, (2000)","R.L. Hu; Department of Mechanical Engineering, University of Hong Kong, Hong Kong; email: raloonhu@hku.hk","","Trans Tech Publications Ltd","","","","","","10139826","","KEMAE","","English","Key Eng Mat","Conference paper","Final","","Scopus","2-s2.0-33847069217" +"D'Aquino M.; Bertotti G.; Serpico C.; Mayergoyz I.D.; Bonin R.","D'Aquino, M. (9732823500); Bertotti, G. (7005370974); Serpico, C. (23013514800); Mayergoyz, I.D. (35495971500); Bonin, R. (9736915400)","9732823500; 7005370974; 23013514800; 35495971500; 9736915400","Foldover, quasi-periodicity, and spin-wave instabilities in ultra-thin magnetic films","2006","IEEE Transactions on Magnetics","42","10","77388799","3195","3197","2","4","10.1109/TMAG.2006.880154","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-41549122567&doi=10.1109%2fTMAG.2006.880154&partnerID=40&md5=81bf45caf75ae4752fb1da22d5e55815","Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, Napoli, I-80125, Italy; Istituto Nazionele di Ricerca Metrologica (INRiM), Torino, I-10135, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States","D'Aquino M., Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, Napoli, I-80125, Italy; Bertotti G., Istituto Nazionele di Ricerca Metrologica (INRiM), Torino, I-10135, Italy; Serpico C., Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, Napoli, I-80125, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States; Bonin R., Istituto Nazionele di Ricerca Metrologica (INRiM), Torino, I-10135, Italy","We study magnetization dynamics in a uniaxial ultra-thin ferromagnetic disk subject to spatially uniform microwave external fields. As a consequence of the rotational invariance of the system, the only admissible spatially uniform steady states are periodic (P-modes) and quasi-periodic (Q-modes) modes. The stability of P-modes versus spatially uniform and nonuniform perturbations is studied by using spin-wave analysis and the instability diagram for all possible P-modes is computed. The predictions of the spin-wave analysis are compared with micromagnetic simulations. © 2006 IEEE.","Ferromagnetic resonance; Foldover; Landau-Lifshitz-Gilbert (LLG) equation; Spin-waves","Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Multilayers; Foldover; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Micromagnetic simulations; Quasi-periodicities; Rotational invariances; Spin-wave instabilities; Ultra thin magnetic films; Spin waves","","","","","BURC; MIUR-FIRB, (RBAU01B2T8)","This work was supported in part by the Italian MIUR-FIRB under Grant RBAU01B2T8 and by the BURC (Campania Region Project).","Kakazei G.N., Et al., Appl. Phys. Lett., 85, pp. 443-445, (2004); Dobin A.Y., Victora R.H., Phys. Rev. Lett., 90, pp. 1-4, (2003); Safonov V.L., J. Appl. Phys., 95, pp. 7145-7150, (2004); Suhl H., J. Phys. Chem. Solids, 1, pp. 209-227, (1957); Kiselev S.I., Et al., Nature, 425, pp. 380-383, (2003); Bertotti G., Et al., Phys. Rev. Lett., 86, pp. 724-727, (2001); Bertotti G., Et al., Phys. Rev. Lett., 87, pp. 1-4, (2001); Aharoni A., Introduction to the Theory of Ferromagnetism, (2001); Perko L., Differential Equations and Dynamical Systems, (1996); Schabes M.E., Aharoni A., IEEE Trans. Magn., MAG-23, 6, (1987); D'Aquino M., Et al., J. Comp. Phys., 209, pp. 730-753, (2005)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-41549122567" +"Landis C.M.","Landis, Chad M. (7102655133)","7102655133","A continuum thermodynamics formulation for micro-magneto-mechanics with applications to ferromagnetic shape memory alloys: Application to domain wall - Twin boundary dissociation","2008","Proceedings of SPIE - The International Society for Optical Engineering","6929","","69291O","","","","0","10.1117/12.782708","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-44949096676&doi=10.1117%2f12.782708&partnerID=40&md5=452558f1922ae41b345143190d512734","University of Texas at Austin, Aerospace Engineering and Engineering Mechanics; Austin, TX 78712-0235, 210 East 24th Street, C0600, United States","Landis C.M., University of Texas at Austin, Aerospace Engineering and Engineering Mechanics, Austin, TX 78712-0235, 210 East 24th Street, C0600, United States","A continuum thermodynamics formulation for micromagnetics coupled with mechanics is devised to model the evolution of magnetic domain and martensite twin structures in ferromagnetic shape memory alloys. The theory falls into the class of phase-field or diffuse-interface modeling approaches. In addition to the standard mechanical and magnetic balance laws, a two sets of micro-forces their associated balance laws are postulated, one set for the magnetization order parameter and one set for the martensite order parameter. The second law of thermodynamics is analyzed to identify the appropriate material constitutive relationships. The general formulation does not constrain the magnitude of the magnetization to be constant, allowing for the possibilities of spontaneous magnetization changes associated with strain and temperature. The equations governing the evolution of the magnetization are shown to reduce to the commonly accepted Landau-Lifshitz-Gilbert equations when the magnetization magnitude is constant. Numerical solutions to the governing equations are presented to investigate the fundamental interactions between the magnetic domain wall and the martensite twin boundary in ferromagnetic shape memory alloys. Calculations are performed to determine under what conditions the magnetic domain wall and the martensite twin boundary can be dissociated, resulting in a limit to the actuating strength of the material.","domain wall - twin boundary dissociation; ferromagnetic shape memory alloy","Alloys; Boundary conditions; Composite materials; Composite micromechanics; Dynamics; Elastohydrodynamics; Evolutionary algorithms; Ferromagnetic materials; Ferromagnetism; Magnetic domains; Magnetic materials; Magnetic structure; Magnetization; Magnets; Martensite; Mathematical morphology; Mechanics; Metals; Model structures; Nanocrystalline alloys; Numerical methods; Phase interfaces; Pigments; Set theory; Shape memory effect; Standards; Strength of materials; Thermodynamics; Walls (structural partitions); (e ,2e) theory; (I ,J) conditions; Balance laws; Constitutive relationships; continuum thermodynamics; Evolution (CO); Ferromagnetic shape memory alloy (FSMA); General (CO); Governing equations; interface modeling; Landau Lifshitz Gilbert (LLG) equations; Magnetic (CE); Magnetic balance; Magnetic domain walls; Micromagnetics; Numerical solutions; Order parameter (OP); phase fields; Second law of thermodynamics; Spontaneous magnetization; Strength (IGC: D5/D6); Twin boundaries; Twin structures; Magnetism","","","","","","","Landis C.M., A continuum thermodynamics formulation for micro-magneto-mechanics with applications to ferromagnetic shape memory alloys, Proceedings of SPIE, 6526, pp. 652625-652631, (2007); Fried E., Gurtin M.E., Continuum theory of thermally induced phase transitions based on an order parameter, Physica D, 68, pp. 326-343, (1993); Fried E., Gurtin M.E., Dynamic solid-solid transitions with phase characterized by an order parameter, Physica D, 72, pp. 287-308, (1994); Gurtin M.E., Generalized Ginzburg-Landau and Cahn-Hilliard equations based on a microforce balance, Physica D, 92, pp. 178-192, (1996); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjet, 8, pp. 153-169, (1935); Gilbert T.L., Physical Review, 100, (1955); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Transactions on Magnetics, 40, pp. 3443-3449, (2004); Coleman R.D., Noll W., The thermodynamics of elastic materials with heat conduction and viscosity, Archive of Rational Mechanics and Analysis, 13, pp. 167-178, (1963); Su Y., Landis C.M., Continuum thermodynamics of ferroelectric domain evolution: Theory, finite element implementation and application to domain wall pinning, Journal of the Mechanics and Physics of Solids, 55, pp. 280-305, (2007); Karaca H.E., Karaman I., Basaran B., Chumlyakov Y.I., Maier H.J., Magnetic field and stress induced martensite reorientation in NiMnGa ferromagnetic shape memory alloy single crystals, Acta Materialia, 54, pp. 233-245, (2006); Kiefer B., Karaca H.E., Lagoudas D.C., Karaman I., Characterization and modeling of the magnetic fieldinduced strain and work output in magnetic shape memory alloys, Journal of Magnetism and Magnetic Materials, 312, pp. 164-175, (2007)","C. M. Landis; University of Texas at Austin, Aerospace Engineering and Engineering Mechanics, United States; email: landis@mail.utexas.edu","","","The International Society for Optical Engineering (SPIE); American Society of Mechanical Engineers","Behavior and Mechanics of Multifunctional and Composite Materials 2008","10 March 2008 through 13 March 2008","San Diego, CA","72183","0277786X","978-081947115-4","PSISD","","English","Proc SPIE Int Soc Opt Eng","Conference paper","Final","","Scopus","2-s2.0-44949096676" +"Cho S.G.; Kim J.; Kim I.; Kim K.H.; Yamaguchi M.","Cho, S.G. (35589593800); Kim, J. (58166414700); Kim, I. (57709596900); Kim, K.H. (34770617200); Yamaguchi, M. (55541020100)","35589593800; 58166414700; 57709596900; 34770617200; 55541020100","Effect of measurement geometry on permeability extracted by a broadband method","2007","Physica Status Solidi (A) Applications and Materials Science","204","12","","4133","4136","3","2","10.1002/pssa.200777230","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-38049162442&doi=10.1002%2fpssa.200777230&partnerID=40&md5=8cfd35452455b40f7f879ed14e2a0f42","Department of Metallurgy and Materials Engineering, Hanyang University, Ansan, 425-791, South Korea; Central R and D Centre, Samsung Electro-Mechanics Co., LTD., Suwon, 443-743, South Korea; Department of Physics, Yeungnam University, Gyeongsan, 712-749, South Korea; Department of Electrical and Communication Engineering, Tohoku University, Sendai, 980-8579, Japan","Cho S.G., Department of Metallurgy and Materials Engineering, Hanyang University, Ansan, 425-791, South Korea; Kim J., Department of Metallurgy and Materials Engineering, Hanyang University, Ansan, 425-791, South Korea; Kim I., Central R and D Centre, Samsung Electro-Mechanics Co., LTD., Suwon, 443-743, South Korea; Kim K.H., Department of Physics, Yeungnam University, Gyeongsan, 712-749, South Korea; Yamaguchi M., Department of Electrical and Communication Engineering, Tohoku University, Sendai, 980-8579, Japan","A broadband coplanar waveguide method, recognized as a simple and effective broadband permeability measurement tool, was used to measure the frequency dependent permeability of various magnetic thin films. It was revealed that measured permeability was strongly dependent on the dimension of the films and the geometry of the waveguide. This dependency was proven to result from the confinement of magnetic fields in the films by LLG equation. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.","","Computational geometry; Coplanar waveguides; Magnetic fields; Magnetic permeability; Broadband coplanar waveguide method; Broadband permeability measurement tools; Measurement geometry; Thin films","","","","","","","Queffelec P., Gelin P., Gieraltowski J., Loaec J., IEEE Trans. Magn, 30, (1994); Ding Y., Klemmer T.J., Crawford T.M., J. Appl. Phys, 96, (2004); Alexander Jr. C., Rantschler J., Silver T.J., Kabos P., J. Appl. Phys, 87, (2000); Kim I., Kim J., J. Magn. Magn. Mater, 291, (2005); Yamaguchi M., Et al., Trans. Magn. Soc. Jpn, 3, (2003); Ito T., Mitta R., IEEE Trans. Microw. Theory Tech, 21, (1973); Barry W., IEEE Trans. Microw. Theory Tech, 34, (1986); Moraitakis E., Kompotiatis L., Pissas M., Niarchos D., J. Magn. Magn. Mater, 222, (2000); Ghione G., Naldi C.U., IEEE Trans. Microw. Theory Tech, 35, (1987); Bedair S.B., Wolff I., IEEE Trans. Microw. Theory Tech, 40, (1992); Osborn J.A., Phys. Rev, 67, (1945); Seemann K., Leiste H., Bekker V., J. Magn. Magn. Mater, 278, (2004)","J. Kim; Department of Metallurgy and Materials Engineering, Hanyang University, Ansan, 425-791, South Korea; email: jina@hanyang.ac.kr","","","","","","","","18626319","","PSSAB","","English","Phys. Status Solidi A Appl. Mater. Sci.","Article","Final","","Scopus","2-s2.0-38049162442" +"Ramprecht J.; Sjöberg D.","Ramprecht, J. (24470578200); Sjöberg, D. (6603778677)","24470578200; 6603778677","On the feasibility of using ferromagnetic materials for thin em absorbers","2007","2007 International Conference on Electromagnetics in Advanced Applications, ICEAA'07","","","4387303","324","327","3","1","10.1109/ICEAA.2007.4387303","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-47349103291&doi=10.1109%2fICEAA.2007.4387303&partnerID=40&md5=c41d1037a70127e43df6c19585e34c93","Division of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Teknikringen 33, Sweden; Department of Electrical and Information Technology, Faculty of Engineering, Lund University, SE-221 00 Lund, Sweden","Ramprecht J., Division of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Teknikringen 33, Sweden; Sjöberg D., Department of Electrical and Information Technology, Faculty of Engineering, Lund University, SE-221 00 Lund, Sweden","In this paper the magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. We show that with the aid of a static magnetic bias field the material can be switched between a Lorentz-like material with a resonance frequency and a material exhibiting a magnetic conductivity. The reflection from a magnetic material backed by a perfect electrical conductor (PEC) is then analyzed. It is found that one can achieve low reflection (around -20 dB) for a quite large bandwidth (more than two decades). © 2007 IEEE.","","Electromagnetism; Ferromagnetic materials; Ferromagnetism; Magnetic devices; Magnetism; Reflection; Resonance; Advanced applications; Electro magnetics; International conferences; Landau Lifshitz Gilbert (LLG) equations; Lorentz like material; Magnetic (CE); Magnetic biasing; Magnetic conductivities; Perfect electrical conductor (PEC); Resonance frequencies; Magnetic materials","","","","","","","Musal J.H.M., Hahn H.T., Thinlayer electromagnetic absorber design, IEEE Trans. Magnetics, 25, pp. 3851-3853, (1989); Kim S.S., Han D., Microwave absorbing properties of sintered Ni-Zn ferrite, IEEE Trans. Magnetics, 30, 6, pp. 4554-4556, (1994); Pinho M.S., Gregori M.L., Nunes R.C.R., Soares B.G., Performance of radar absorbing materials by waveguide measurements for X- and Ku-band frequencies, European Polymer Journal, 38, pp. 2321-2327, (2002); Zhang B., Lu G., Fenga Y., Xiong J., Lu H., Electromagnetic and microwave absorption properties of Alnico powder composites, Journal of Magnetism and Magnetic Materials, 299, pp. 205-210, (2006); Collin R.E., Foundations for Microwave Engineering, (1992); Pozar D.M., Microwave Engineering, (1990); Knott E.F., Shaeffer J.F., Tuley M.T., Radar Cross Section, (2004); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Physik. Z. Sowjetunion, 8, pp. 153-169, (1935); Wu L.Z., Ding J., Jiang H.B., Chen L.F., Ong C.K., Particle size influence to the microwave properties of iron based magnetic particulate composites, Journal of Magnetism and Magnetic Materials, 285, pp. 233-239, (2005); Yu Y., Harrel J.W., FMR spectra of oriented γ-Fe 2O3, Co-γ-Fe2O3, CrO 2, and MP tapes, IEEE Trans. Magnetics, 30, 6, pp. 4083-4085, (1994); Kittel C., Introduction to Solid State Physics, (1996); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magnetics, 50, pp. 3443-3449, (2004); Barybin A.A., Modal expansions and orthogonal complements in the theory of complex media waveguide excitation by external sources for isotropic, anisotropic, and bianisotropic media, Progress in Electromagnetics Research, 19, pp. 241-300, (1998)","J. Ramprecht; Division of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Teknikringen 33, Sweden; email: jorgen.ramprecht@ee.kth.se","","","Istituto Superiore Mario Boella Tecnol. Inf. Teleornicazioni; Torino Wireless Foundation","2007 International Conference on Electromagnetics in Advanced Applications, ICEAA'07","17 September 2007 through 21 September 2007","Torino","72484","","1424407672; 978-142440767-5","","","English","Int. Conf. Electromagn. Adv. Appl., ICEAA, Ed.","Conference paper","Final","","Scopus","2-s2.0-47349103291" +"Magiera M.P.; Brendel L.; Wolf D.E.; Nowak U.","Magiera, M.P. (22734553500); Brendel, L. (55927565500); Wolf, D.E. (7402650690); Nowak, U. (7003770249)","22734553500; 55927565500; 7402650690; 7003770249","Spin waves cause non-linear friction","2011","EPL","95","1","17010","","","","13","10.1209/0295-5075/95/17010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79960177045&doi=10.1209%2f0295-5075%2f95%2f17010&partnerID=40&md5=69feac2decd23e802e4cbdf37cafb73d","Faculty of Physics, CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Department of Physics, University of Konstanz, D-78457 Konstanz, Germany","Magiera M.P., Faculty of Physics, CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Brendel L., Faculty of Physics, CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Wolf D.E., Faculty of Physics, CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Nowak U., Department of Physics, University of Konstanz, D-78457 Konstanz, Germany","Energy dissipation is studied for a hard magnetic tip that scans a soft magnetic substrate. The dynamics of the atomic moments are simulated by solving the Landau-Lifshitz-Gilbert (LLG) equation numerically. The local energy currents are analysed for the case of a Heisenberg spin chain taken as substrate. This leads to an explanation for the velocity dependence of the friction force: The non-linear contribution for high velocities can be attributed to a spin wave front pushed by the tip along the substrate. Copyright © 2011 EPLA.","","","","","","","","","Urbakh M., Klafter J., Gourdon D., Israelachvili J., Nature, 430, 6999, (2004); Corberi F., Gonnella G., Lamura A., Phys. Rev. Lett., 81, 18, (1998); Acharyya M., Chakrabarti B.K., Phys. Rev. B, 52, 9, (1995); Kadau D., Hucht A., Wolf D.E., Phys. Rev. Lett., 101, 13, (2008); Angst S., Hucht A., Wolf D.E., (2011); Hucht A., Phys. Rev. e, 80, 6, (2009); Igloi F., Pleimling M., Turban L., Phys. Rev. e, 83, 4, (2011); Hilhorst H.J., J. Stat. Mech., 2011, 4, (2011); Fusco C., Wolf D.E., Nowak U., Phys. Rev. B, 77, 17, (2008); Magiera M.P., Brendel L., Wolf D.E., Nowak U., EPL, 87, 2, (2009); Magiera M.P., Wolf D.E., Brendel L., Nowak U., IEEE Trans. Magn., 45, 10, (2009); Magiera M.P., Wolf D.E., Munster G., Wolf D.E., Kremer M., Simulation of Magnetic Friction, in Proceedings of the NIC Symposium 2010, 3, (2010); Demery V., Dean D.S., Phys. Rev. Lett., 104, 8, (2010); Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. Magn., 40, 6, (2004); Neusser S., Grundler D., Adv. Mater., 21, 28, (2009); Serga A.A., Chumak A.V., Hillebrands B., J. Phys. D: Appl. Phys., 43, 26, (2010); Coey J.M.D., Magnetism and Magnetic Materials, (2010)","M.P. Magiera; Faculty of Physics, CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; email: martin.magiera@uni-due.de","","","","","","","","12864854","","","","English","EPL","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-79960177045" +"Iyer R.; Millhollon J.; Long K.","Iyer, R. (55420081100); Millhollon, J. (37063496000); Long, K. (59091069600)","55420081100; 37063496000; 59091069600","Micromagnetics with eddy currents","2011","Journal of Physics: Conference Series","268","1","012011","","","","0","10.1088/1742-6596/268/1/012011","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79952681365&doi=10.1088%2f1742-6596%2f268%2f1%2f012011&partnerID=40&md5=71bf10dca8de82a2cc6bb5134652d822","Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, United States","Iyer R., Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, United States; Millhollon J., Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, United States; Long K., Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, United States","In this paper, we study the modified Landau-Lifshitz-Gilbert (LLG) equation for of a conducting, magnetic body. The modified LLG equations include the magnetic field due to eddy currents in the total effective magnetic field. We derive an expression for the magnetic field due to eddy current losses and show that it is well defined. We then show that the work done by the eddy currents in opposing the change of magnetization is a Rayleigh type dissipation function, and derive the modified LLG equations using the calculus of variations. Finally, we show that the modified LLG equations lead to a decrease in the Gibbs energy. This implies that the LLG equations describes a dynamic process proceeding spontaneously forward in time. © Published under licence by IOP Publishing Ltd.","","Calculations; Magnetic fields; Magnetism; Calculus of variations; Dissipation functions; Dynamic process; Eddy current-loss; Landau-Lifshitz-Gilbert equations; LLG equation; Micromagnetics; Rayleigh; Eddy currents","","","","","","","Diaz G., Arboleya P., Gonzalez-Moran C., Gomez-Aleixandre J., IET Electron. Power Appl., 1, (2007); Ekanayake D., Iyer R., Dayawansa W., Proc. American Control Conf., 4321, (2007); Hertel R., Guided Spin Waves, Handbook of Magnetism and Advanced Magnetic Materials, 2, pp. 1003-1020, (2007); Willard M., Francavilla T., Harris V., J. Appl. Phys., 97, (2005); Fiorillo F., Novikov A., IEEE Trans. Mag., 26, (1990); Thomas L., Parkin S., Current Induced Domain-wall Motion in Magnetic Nanowires, Handbook of Magnetism and Advanced Magnetic Materials, 2, (2007); Gilbert T.L., IEEE Trans. Mag., 40, (2004); Brown Jr. W.F., Micromagnetics, (1962); D'Aquino M., (2004); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Kronmuller H., Handbook of Magnetism and Advanced Magnetic Materials, 2, (2007); Miltat J., Donahue M., Handbook of Magnetism and Advanced Magnetic Materials, 2, (2007); Schrefl T., Hrkac G., Bance S., Suess D., Ertl O., Fidler J., Handbook of Magnetism and Advanced Magnetic Materials, 2, (2007); Bertotti G., Hysteresis in Magnetism, (1998); Torres L., Martinez E., Lopez-Diaz L., Alejos O., Physica B, 343, (2004); Serpico C., Mayergoyz I.D., Bertotti G., IEEE Trans. Magn., 37, (2001); Landau L., Lifshitz E., Collected Papers of L. D. Landau, (1965); Gilbert T., Kelly J., Proc. Conf. Magnetism and Magnetic Materials, (1955); Leathem J.G., Volume and Surface Integrals Used in Physics, (1960)","R. Iyer; Department of Mathematics and Statistics, Texas Tech University, Lubbock, TX 79409, United States; email: ram.iyer@ttu.edu","","Institute of Physics Publishing","","","","","","17426588","","","","English","J. Phys. Conf. Ser.","Conference paper","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-79952681365" +"Vagin D.V.; Polyakov O.P.","Vagin, Dmitry V. (16033425600); Polyakov, Oleg P. (7003489755)","16033425600; 7003489755","Effect of sample shape on nonlinear magnetization dynamics under an external magnetic field","2008","Journal of Magnetism and Magnetic Materials","320","24","","3394","3399","5","6","10.1016/j.jmmm.2008.07.021","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-53949116371&doi=10.1016%2fj.jmmm.2008.07.021&partnerID=40&md5=0257df5a8533315fd27038eb2c49fb0c","Faculty of Physics, M.V. Lomonosov Moscow State University, Vorobiovy gory, Moscow 119992, Russian Federation","Vagin D.V., Faculty of Physics, M.V. Lomonosov Moscow State University, Vorobiovy gory, Moscow 119992, Russian Federation; Polyakov O.P., Faculty of Physics, M.V. Lomonosov Moscow State University, Vorobiovy gory, Moscow 119992, Russian Federation","Effect of sample shape on the nonlinear collective dynamics of magnetic moments in the presence of oscillating and constant external magnetic fields is studied using the Landau-Lifshitz-Gilbert (LLG) approach. The uniformly magnetized sample is considered to be an ellipsoidal axially symmetric particle described by demagnetization factors and uniaxial crystallographic anisotropy formed some angle with an applied field direction. It is investigated as to how the change in particle shape affects its nonlinear magnetization dynamics. To produce a regular study, all results are presented in the form of bifurcation diagrams for all sufficient dynamics regimes of the considered system. In this paper, we show that the sample's (particle's) shape and its orientation with respect to the external field (system configuration) determine the character of magnetization dynamics: deterministic behavior and appearance of chaotic states. A simple change in the system's configuration or in the shapes of its parts can transfer it from chaotic to periodic or even static regime and back. Moreover, the effect of magnetization precession stall and magnetic moments alignment parallel or antiparallel to the external oscillating field is revealed and the way of control of such ""polarized"" states is found. Our results suggest that varying the particle's shape and fields' geometry may provide a useful way of magnetization dynamics control in complex magnetic systems. © 2008.","Bifurcation diagram; Landau-Lifshitz equation; Nonlinear dynamic","Demagnetization; Dynamics; Magnetic field measurement; Magnetic fields; Magnetic materials; Magnetic moments; Magnetism; Magnetization; Magnets; Single crystals; Applied fields; Axially symmetric; Bifurcation diagram; Bifurcation diagrams; Chaotic states; Collective dynamics; Constant external magnetic fields; Crystallographic anisotropy; Demagnetization factors; Deterministic behavior; External fields; External magnetic fields; External-; Landau-Lifshitz equation; Landau-Lifshitz-Gilbert; Magnetic systems; Magnetization dynamics; Magnetization precession; Nonlinear dynamic; Nonlinear magnetization dynamics; Oscillating fields; Particle shapes; Sample shape; System configurations; Magnetic bubbles","","","","","","","Cui Z., Rothmann J., Klaui M., Microelectron. Eng., 61, (2002); Zhu J.G., Zheng Y., Prinz G.A., J. Appl. Phys., 87, (2000); Brown Jr. W.F., Micromagnetics, (1963); Ahieser A.I., Bariyahtar V.G., Peletminskiy S.V., Spin Waves, (1967); Polyakov O.P., Polyakov P.A., Radio Eng. Electron. Phys., 42, (1997); Lisovskiy F.V., Polyakov O.P., JETP Lett., 68, (1998); Alvarez L.F., Pla O., Chubykalo O., Phys. Rev. B, 61, (2000); Lisovskiy F.V., Polyakov O.P., JETP Lett., 73, (2001); Serpico C., Bertotti G., Mayergoyz I., Phys. Rev. Lett., 86, (2001); Chubykalo O., Hannay J.D., Vongsam M., Chantrell R.W., Gonzalez J.M., Phys. Rev. B, 65, (2002); Li Z., Li C., Zhang S., Phys. Rev. B, 74, (2006); Moskowitz R., IEEE Trans. Magn., 2, (1966); Haken H., Advanced Synergetics: Instability Hierarchies of Self-organizing Systems and Devices, (1993); Berge P., Pomeau Y., Vidal L'Ordre dans le haos C., Vers une approche deterministe de la turbulence, (1988); Lichtenberg A.J., Lieberman M.A., Regular and Stochastic Motion, (1983)","D.V. Vagin; Faculty of Physics, M.V. Lomonosov Moscow State University, Vorobiovy gory, Moscow 119992, Russian Federation; email: vagin@gen5521.phys.msu.ru","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-53949116371" +"Ramprecht J.; Sjöberg D.","Ramprecht, J. (24470578200); Sjöberg, D. (6603778677)","24470578200; 6603778677","Biased magnetic materials in ram applications","2007","Progress in Electromagnetics Research","75","","","85","117","32","13","10.2528/PIER07052501","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34547246315&doi=10.2528%2fPIER07052501&partnerID=40&md5=e1f0ea46d8e911cb08408d936150166e","Division of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Teknikringen 33, Sweden; Department of Electrical and Information Technology, Faculty of Engineering, Lund University, SE-221 00 Lund, Sweden","Ramprecht J., Division of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, SE-100 44 Stockholm, Teknikringen 33, Sweden; Sjöberg D., Department of Electrical and Information Technology, Faculty of Engineering, Lund University, SE-221 00 Lund, Sweden","The magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this model demagnetization effects are included. By applying a linearized small signal model of the LLG equation, it was found that the material can be described by an effective permeability and with the aid of a static external biasing field, the material can be switched between a Lorentz-like material and a material that exhibits a magnetic conductivity. Furthermore, the reflection coefficient for normally impinging waves on a PEC covered with a ferro/ferri-magnetic material, biased in the normal direction, is calculated. When the material is switched into the resonance mode, two distinct resonance frequencies in the reflection coefficient were found, one associated with the precession frequency of the magnetization and the other associated with the thickness of the layer. The former of these resonance frequencies can be controlled by the bias field and for a bias field strength close to the saturation magnetization, where the material starts to exhibit a magnetic conductivity, low reflection (around -20 dB) for a quite large bandwidth (more than two decades) can be achieved.","","Bandwidth; Differential equations; Electric conductivity; Random access storage; Saturation magnetization; Switching; External biasing field; Landau-Lifshitz-Gilbert (LLG) equation; Lorentz-like material; Ferromagnetic materials","","","","","","","Knott E.F., Shaeffer J.F., Tuley M.T., Radar Cross Section, (2004); Gustafsson M., RCS reduction of integrated antenna arrays with resistive sheets, J. Electro. Waves Applic, 20, 1, pp. 27-40, (2006); Gustafsson M., Surface integrated dipole arrays with tapered resistive edge sheets, J. Electro. Waves Applic, 21, 6, pp. 713-718, (2007); Ruck G.T., Barrick D.E., Stuart W.D., Krichbaum C.K., Radar Cross Section Handbook, 2, (1970); Sjoberg D., On uniqueness and continuity for the quasi-linear, bianisotropic Maxwell equations, using an entropy condition, Progress In Electromagnetics Research, PIER, 71, pp. 317-339, (2007); Strifors H.C., Gaunaurd G.C., Bistatic scattering by bare and coated perfectly conducting targets of simple shape, J. of Electromagn. Waves and Appl, 20, 8, pp. 1037-1050, (2006); Gong Z.Q., Zhu G.Q., FDTD analysis of an anisotropically coated missile, Progress In Electromagnetics Research, PIER, 64, pp. 69-80, (2006); Musal J.H.M., Hahn H.T., Thin-layer electromagnetic absorber design, IEEE Trans. Magnetics, 25, pp. 3851-3853, (1989); Kim S.S., Han D., Microwave absorbing properties of sintered Ni - Zn ferrite, IEEE Trans. Magnetics, 30, 6, pp. 4554-4556, (1994); Shin J.Y., Oh J.H., The microwave absorbing phenomena of ferrite microwave absorbers, IEEE Trans. Magnetics, 29, 6, pp. 3437-3439, (1993); Cho H.S., Kim S.S., M-hexaferrites with planar magnetic anisotropy and their application to high-frequency microwave absorbers, IEEE Trans. Magnetics, 35, 5, pp. 3151-3253, (1999); Pinho M.S., Gregori M.L., Nunes R.C.R., Soares B.G., Performance of radar absorbing materials by waveguide measurements for X- and Ku-band frequencies, European Polymer Journal, 38, pp. 2321-2327, (2002); Haijun Z., Zhichao L., Chengliang M., Xi Y., Liangying Z., Mingzhong W., Complex permittivity, permeability, and microwave absorption of Zn- and Ti-substituted barium ferrite by citrate sol/gel process, Materials Science and Engineering B, 96, pp. 289-295, (2002); Meshrama M., Agrawal N.K., Sinha B., Misra P., Characterization of M-type barium hexagonal ferrite-based wide band microwave absorber, Journal of Magnetism and Magnetic Materials, 271, pp. 207-214, (2004); Kim S.-S., Kim S.-T., Ahn J.-M., Kim K.-H., Magnetic and microwave absorbing properties of Co-Fe thin films plated on hollow ceramic microspheres of low density, Journal of Magnetism and Magnetic Materials, 271, pp. 39-45, (2004); Zhang B., Lu G., Fenga Y., Xiong J., Lu H., Electromagnetic and microwave absorption properties of Alnico powder composites, Journal of Magnetism and Magnetic Materials, 299, pp. 205-210, (2006); Engstrom C., Sjoberg D., On two numerical methods for homogenization of Maxwell's equations, Journal of Electromagnetic Waves and Applications, 21, 13, pp. 1845-1856, (2007); Wallace J.L., Broadband magnetic microwave absorbers: Fundamental limitations, IEEE Trans. Magnetics, 29, 6, pp. 4209-4214, (1993); Bregar V.B., Advantages of ferromagnetic nanoparticle composites in microwave absorbers, IEEE Trans. Magnetics, 40, 3, pp. 1679-1684, (2004); Wu L.Z., Ding J., Jiang H.B., Chen L.F., Ong C.K., Particle size influence to the microwave properties of iron based magnetic particulate composites, Journal of Magnetism and Magnetic Materials, 285, pp. 233-239, (2005); Collin R.E., Foundations for Microwave Engineering, (1992); Pozar D.M., Microwave Engineering, (1990); Kong J.A., Theory of Electromagnetic Waves, (1975); Jackson J.D., Classical Electrodynamics, (1998); Kittel C., Introduction to Solid State Physics, (1996); Kittel C., Physical theory of ferromagnetic domains, Rev. Mod. Phys, 21, pp. 541-583, (1949); Goodenough J.B., Summary of losses in magnetic materials, IEEE Trans. Magnetics, 38, pp. 3398-3408, (2002); Elliot R.S., An Introduction to Guided Waves and Microwave Circuits, (1993); Sodha M.S., Srivastava N.C., Microwave Propagation in Ferrimagnetics, (1981); Landau L.D., Lifshitz E.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Physik. Z. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magnetics, 50, pp. 3443-3449, (2004); Kikuchi R., On the minimum of magnetization reversal time, J. Appl Phys, 27, pp. 1352-1357, (1956); Mallison J.C., On damped gyromagnetic precession, IEEE Trans. Magnetics, 23, pp. 2003-2004, (1987); Barybin A.A., Excitation theory for space-dispersive active media waveguides, J. Phys. D: Applied Phys, 32, pp. 2014-2028, (1999); Yaghjian A.D., Electric dyadic green's functions in the source region, Proc. IEEE, 68, 2, pp. 248-263, (1980); Barybin A.A., Modal expansions and orthogonal complements in the theory of complex media waveguide excitation by external sources for Isotropic, anisotropic, and bianisotropic media, Progress In Electromagnetics Research, PIER, 19, pp. 241-300, (1998)","","","Electromagnetics Academy","","","","","","10704698","","","","English","Prog. Electromagn. Res.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-34547246315" +"Yang B.-C.; Shu C.; Deng L.-W.; Wu Y.; Li W.-F.","Yang, Bing-Chu (7404472065); Shu, Chang (55133338500); Deng, Lian-Wen (7202008013); Wu, Yi (56093619900); Li, Wen-Fang (57196303042)","7404472065; 55133338500; 7202008013; 56093619900; 57196303042","The main factors effects on absorbing properties of nano-magnetic granular film","2009","Gongneng Cailiao/Journal of Functional Materials","40","10","","1623","1625","2","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-70749140546&partnerID=40&md5=2ea66a706e6765dd4b31720d23eb6e6c","School of Physics Science and Technology, Central South University, Changsha 410083, China","Yang B.-C., School of Physics Science and Technology, Central South University, Changsha 410083, China; Shu C., School of Physics Science and Technology, Central South University, Changsha 410083, China; Deng L.-W., School of Physics Science and Technology, Central South University, Changsha 410083, China; Wu Y., School of Physics Science and Technology, Central South University, Changsha 410083, China; Li W.-F., School of Physics Science and Technology, Central South University, Changsha 410083, China","Based on the Landau-Lifshitz-Gilbert equation, bruggeman effective medium theory and nano-particle films dielectric electric transport theory, calculated the effective permeability and the effective permittivity of the magnetic nanoparticles, an analytic calculation of saturation magnetization, anisotropy field, electrical conductivity and the damping parameter caused on the absorbing properties was presented. The results show that the saturation magnetization, anisotropy field, electrical conductivity and the damping parameter of the nanoparticles have a significant impact on the absorbing properties of nanoparticles. It can effectively improve the absorbing properties by control the electromagnetic paramete of films, this can be applied to design thin film of radar absorbing materials.","Effective medium theory; LLG equation; Microwave absorption; Nano-granular magnetic film","Absorption; Anisotropy; Damping; Electric conductivity; Magnetic films; Magnetic properties; Magnets; Metallic films; Microwaves; Nanoparticles; Statistical mechanics; Absorbing properties; Analytic calculations; Anisotropy field; Damping parameters; Effective medium theories; Effective permeability; Effective permittivity; Electric transport; Electrical conductivity; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic granular films; Magnetic nanoparticles; Microwave absorption; Radar absorbing materials; Significant impacts; Saturation magnetization","","","","","","","Ohnuma S., Lee H.J., Kobayashi N., Et al., IEEE Trans Magn, 37, pp. 2251-2254, (2001); 12, 20, pp. 104-108, (2006); J Magn Mater Devices, 39, 3, pp. 17-20, (2008); Shiiki K., Hori H., J Magn Magn Mater, 290, pp. 456-459, (2005); Ge S., Yao D., Yamaguchi M., Et al., J Phys D: Appl Phys, 40, pp. 3660-3664, (2007); Merrill W.M., Diaz R.E., Et al., IEEE Trans Anten Propa, 47, pp. 142-148, (1999); Lagarkov A.N., Sarychev A.K., Smychkovich Y.R., Et al., Journal of Electromagnetic Waves Application, 6, 9, pp. 1159-1176, (1992); 39, 1, pp. 59-63, (2008); Sohn J.C., Byun D.J., Lim S.H., J Magn Magn Mater, 272-276, (2004); Ohnuma S., Fujimori H., Mitani S., Et al., J Appl Phys, 79, 8, (1996); Ohnuma S., Lee H.J., Kobayashi N., Et al., IEEE Trans Magn, 37, 4, pp. 2251-2254, (2001); Munakata M., Motoyama M., Yagi M., Et al., IEEE Trans Magn, 38, 5, pp. 3147-3149, (2002)","","","","","","","","","10019731","","GOCAE","","Chinese","Gongneng Cailiao","Article","Final","","Scopus","2-s2.0-70749140546" +"Cheng X.Z.; Jalil M.B.A.; Lee H.K.","Cheng, X.Z. (10539190400); Jalil, M.B.A. (7006821429); Lee, Hwee Kuan (12544939000)","10539190400; 7006821429; 12544939000","Time-quantified Monte Carlo algorithm for interacting spin array micromagnetic dynamics","2006","Physical Review B - Condensed Matter and Materials Physics","73","22","224438","","","","15","10.1103/PhysRevB.73.224438","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33745653277&doi=10.1103%2fPhysRevB.73.224438&partnerID=40&md5=6c452148f5898b299ff759233a0b778f","Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Data Storage Institute, DSI Building, 117608, Singapore, 5 Engineering Drive 1, Singapore","Cheng X.Z., Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Lee H.K., Data Storage Institute, DSI Building, 117608, Singapore, 5 Engineering Drive 1, Singapore","In this paper, we reexamine the validity of using time-quantified Monte Carlo (TQMC) method in simulating the stochastic dynamics of interacting magnetic nanoparticles. The Fokker-Planck coefficients corresponding to both TQMC and the Langevin dynamical equation (Landau-Lifshitz-Gilbert, LLG) are derived and compared in the presence of interparticle interactions. The time quantification factor is obtained and justified. Numerical verification is shown by using TQMC and Langevin methods in analyzing spin-wave dispersion in a linear array of magnetic nanoparticles. © 2006 The American Physical Society.","","","","","","","","","Nowak U., Chantrell R.W., Kennedy E.C., Phys. Rev. Lett., 84, (2000); Hinzke D., Nowak U., Phys. Rev. B, 61, (2000); Chubykalo O., Nowak U., Smirnov-Rueda R., Wongsam M.A., Chantrell R.W., Gonzalez J.M., Phys. Rev. B, 67, (2003); Cheng X.Z., Jalil M.B.A., Lee H.K., Okabe Y., Phys. Rev. B, 72, (2005); Cheng X.Z., Jalil M.B.A., Lee H.K., Okabe Y., Phys. Rev. Lett., 96, (2006); Chubykalo-Fresenko O., Chantrell R.W., IEEE Trans. Magn., 41, (2005); Brown W.F., Phys. Rev., 130, (1963); Risken H., The Fokker-Planck Equation, (1967); Dimitrov D.A., Wysin G.M., Phys. Rev. B, 50, (1994); Kittel C., Introduction to Solid State Physics, (1996); Chantrell R.W., Hannay J.D., Wongsam M.A., IEEE Trans. Magn., 34, (1998); Chubykalo O., Hannay J.D., Wongsam M., Chantrell R.W., Gonzalez J.M., Phys. Rev. B, 65, (2002); Novotny M.A., Phys. Rev. Lett., 74, (1995); Chubykalo O., Smirnov-Rueda R., Gonzalez J.M., Wongsam M.A., Chantrell R.W., Nowak U., J. Magn. Magn. Mater., 266, (2003)","","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-33745653277" +"Bonin R.","Bonin, Roberto (9736915400)","9736915400","Dependence of magnetization dynamics on anisotropy in thin films driven by spin-polarized currents","2010","IEEE Transactions on Magnetics","46","2","5393210","258","261","3","2","10.1109/TMAG.2009.2033204","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-76249097249&doi=10.1109%2fTMAG.2009.2033204&partnerID=40&md5=04962b0c42f23a2d762b285c1b5bab04","Politecnico di Torino-Sede di Verrès, I-11029 Verrès, Aosta, Italy","Bonin R., Politecnico di Torino-Sede di Verrès, I-11029 Verrès, Aosta, Italy","An analytical study of magnetization dynamics in nanomagnets subjected to magnetic fields and spin-polarized electrical currents is discussed. It is shown how the presence of various dynamical regimes depends on magnetic properties of the investigated system, in particular, it is demonstrated that the magnetization response is different if we consider magnetic systems with either uniaxial in-plane or easy-plane anisotropy. © 2010 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Magnetic anisotropy; Spin-torque","Magnetization; Spin dynamics; Spin polarization; Analytical studies; Easy-plane anisotropy; Electrical current; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetization response; Spin polarized currents; Spin torque; Magnetic anisotropy","","","","","European Social Found; Italian Ministry of Lavoro e Previdenza Sociale; European Commission, EC; Regione Autonoma Valle d'Aosta","The author would like to thank G. Bertotti for helpful suggestions and C. Serpico, I. D. Mayergoyz, and M. d’Aquino for useful discussions. This work was supported in part by the European Union (European Social Found), Regione Autonoma Valle d’Aosta (Italy), and the Italian Ministry of Lavoro e Previdenza Sociale.","Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, (1996); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, Phys. Rev. Lett., 84, pp. 3149-3152, (2000); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Microwave oscillations of a nanomagnet driven by a spin-polarized current, Nature, 425, pp. 380-383, (2003); Rippard W.H., Pufall M.R., Kaka S., Russek S.E., Silva T.J., Direct-current induced dynamics in CoFe/NiFe point contacts, Phys. Rev. Lett., 92, (2004); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Garcia A.G.F., Buhrman R.A., Ralph D.C., Spin-transfer excitations of permalloy nanopillars for large applied currents, Phys. Rev. B, 72, (2005); Houssameddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Cyrille M.-C., Redon O., Dieny B., Spin-torque oscillator using a perpendicular polarizer and a planar free layer, Nature Mat., 6, pp. 447-453, (2007); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., D'Aquino M., Bonin R., Magnetization switching and microwave oscillations in nanomagnets driven by spin-polarized currents, Phys. Rev. Lett., 94, (2005); Bonin R., Bertotti G., Mayergoyz I.D., Serpico C., Spin-torque driven magnetization dynamics in nanomagnets subject to magnetic fields perpendicular to the sample plane, J. Appl. Phys., 99, (2006); Ebels U., Houssameddine D., Firastrau I., Gusakova D., Thirion C., Dieny B., Buda-Prejbeanu L.D., Macrospin description of the perpendicular polarizer-planar free-layer spin-torque oscillator, Phys. Rev. B, 78, (2008); Bazaliy Y.B., Jones B.A., Zhang S.C., Current-induced magnetization switching in small domains of different anisotropies, Phys. Rev. B, 69, (2004); Mangin S., Ravelosona D., Katine J.A., Carey M.J., Terris B.D., Fullerton E.E., Current-induced magnetization reversal in nanopillars with perpendicular anisotropy, Nature Mater., 5, pp. 210-215, (2006); Perko L., Differential Equations and Dynamical Systems, (1996); Bonin R., Serpico C., Bertotti G., Mayergoyz I.D., D'Aquino M., Analytical study of magnetization dynamics driven by spin-polarized currents, Eur. Phys. J. B, 59, (2007); Bertotti G., Mayergoyz I.D., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Bonin R., Bertotti G., Serpico C., Mayergoyz I.D., D'Aquino M., Analytical treatment of synchronization of spin-torque oscillators by microwave magnetic fields, Eur. Phys. J. B, 68, pp. 221-231, (2009); Bertotti G., Bonin R., Serpico C., D'Aquino M., Mayergoyz I.D., Spin-wave analysis of uniaxial nanopillar devices, J. Appl. Phys., 105, (2009)","R. Bonin; Politecnico di Torino-Sede di Verrès, I-11029 Verrès, Aosta, Italy; email: bonin.roberto@gmail.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-76249097249" +"Magiera M.P.; Brendel L.; Wolf D.E.; Nowak U.","Magiera, M.P. (22734553500); Brendel, L. (55927565500); Wolf, D.E. (7402650690); Nowak, U. (7003770249)","22734553500; 55927565500; 7402650690; 7003770249","Spin excitations in a monolayer scanned by a magnetic tip","2009","EPL","87","2","26002","","","","25","10.1209/0295-5075/87/26002","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-75349103270&doi=10.1209%2f0295-5075%2f87%2f26002&partnerID=40&md5=90a0ba37ea1a3b039d27025f2e8250a8","Department of Physics and CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Theoretical Physics, University of Konstanz, D-78457 Konstanz, Germany","Magiera M.P., Department of Physics and CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Brendel L., Department of Physics and CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Wolf D.E., Department of Physics and CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; Nowak U., Theoretical Physics, University of Konstanz, D-78457 Konstanz, Germany","Energy dissipation via spin excitations is investigated for a hard ferromagnetic tip scanning a soft magnetic monolayer. We use the classical Heisenberg model with Landau-Lifshitz-Gilbert (LLG) dynamics including a stochastic field representing finite temperatures. The friction force depends linearly on the velocity (provided it is small enough) for all temperatures. For low temperatures, the corresponding friction coefficient is proportional to the phenomenological damping constant of the LLG equation. This dependence is lost at high temperatures, where the friction coefficient decreases exponentially. These findings can be explained by properties of the spin polarisation cloud dragged along with the tip. Copyright © 2009 EPLA.","","","","","","","","","Persson B., Sliding Friction, (1998); Urbakh M., Klafter J., Gourdon D., Israelachvili J., Nature, 430, 6999, (2004); Gnecco E., Bennewitz R., Gyalog T., Meyer E., J. Phys.: Condens. Matter, 13, 31, (2001); Acharyya M., Chakrabarti B.K., Phys. Rev. B, 52, 9, (1995); Ortin J., Goicoechea J., Phys. Rev. B, 58, 9, (1998); Corberi F., Gonnella G., Lamura A., Phys. Rev. Lett., 81, 18, (1998); Kadau D., Hucht A., Wolf D.E., Phys. Rev. Lett., 101, 13, (2008); Fusco C., Wolf D.E., Nowak U., Phys. Rev. B, 77, 17, (2008); Grutter P., Liu Y., Leblanc P., Durig U., Appl. Phys. Lett., 71, 2, (1997); Schmidt R., Lazo C., Holscher H., Pi U.H., Caciuc V., Schwarz A., Wiesendanger R., Heinze S., Nano Lett., 9, 1, (2009); Zworner O., Holscher H., Schwarz U.D., Wiesendanger R., Appl. Phys. A, 66, 7, (1998); Gnecco E., Bennewitz R., Gyalog T., Loppacher C., Bammerlin M., Meyer E., Guntherodt H.-J., Phys. Rev. Lett., 84, 6, (2000); Prandtl L., Z. Angew. Math. Mech., 8, 2, (1928); Tomlinson G.A., Philos. Mag., 7, (1929); Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, (1935); Gilbert T.L., IEEE Trans. Magn., 40, 6, (2004); Neel L., C. R. Acad. Sci. Paris, 228, (1949); Brown W.F., Phys. Rev., 130, 5, (1963); Magiera M.P., (2008); Horsthemke W., Lefever R., Noise-Induced Transitions, (1983); Garcia-Palacios J.L., Lzaro F.L., Phys. Rev. B, 58, 22, (1998)","M. P. Magiera; Department of Physics and CeNIDE, University of Duisburg-Essen, D-47048 Duisburg, Germany; email: martin.magiera@uni-due.de","","","","","","","","12864854","","","","English","EPL","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-75349103270" +"D'Aquino M.; Serpico C.; Coppola G.; Mayergoyz I.D.; Bertotti G.","D'Aquino, M. (9732823500); Serpico, C. (23013514800); Coppola, G. (55352758900); Mayergoyz, I.D. (35495971500); Bertotti, G. (7005370974)","9732823500; 23013514800; 55352758900; 35495971500; 7005370974","Midpoint numerical technique for stochastic Landau-Lifshitz-Gilbert dynamics","2006","Journal of Applied Physics","99","8","08B905","","","","64","10.1063/1.2169472","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33646717515&doi=10.1063%2f1.2169472&partnerID=40&md5=e42238932a18d5b11fb073b133ed0b26","Department of Electrical Engineering, University of Napoli Federico II, Napoli I-80125, Italy; DETEC, University of Napoli Federico II, Napoli I-80125, Italy; ECE Department, University of Maryland, College Park, MD 20742, United States; UMIACS, University of Maryland, College Park, MD 20742, United States; Istituto Elettrotecnico Nazionale (IEN), Galileo Ferraris (INRIM), I-10135 Torino, Italy","D'Aquino M., Department of Electrical Engineering, University of Napoli Federico II, Napoli I-80125, Italy; Serpico C., Department of Electrical Engineering, University of Napoli Federico II, Napoli I-80125, Italy; Coppola G., DETEC, University of Napoli Federico II, Napoli I-80125, Italy; Mayergoyz I.D., ECE Department, University of Maryland, College Park, MD 20742, United States, UMIACS, University of Maryland, College Park, MD 20742, United States; Bertotti G., Istituto Elettrotecnico Nazionale (IEN), Galileo Ferraris (INRIM), I-10135 Torino, Italy","The implicit midpoint time-integration technique is applied to the stochastic Landau-Lifshitz-Gilbert (LLG) equation. The numerical scheme converges to the Stratonovich solution in the limit of vanishing time step. It preserves the magnetization magnitude and the main energy balance properties of the LLG equation independently of the time step. The numerical technique is then applied to the study of superparamagnetic state in a small spheroidal particle, and the numerical results are compared with the theory. © 2006 American Institute of Physics.","","Convergence of numerical methods; Numerical analysis; Superparamagnetism; Theorem proving; Magnetization magnitude; Midpoint time-integration technique; Stochastic Landau-Lifshitz-Gilbert (LLG) equation; Stochastic Landau-Lifshitz-Gilbert dynamics; Magnetization","","","","","MIUR-FIRB, (RBAU01B2T8); Regione Campania BURC","This work was supported by the MIUR-FIRB Contract No. RBAU01B2T8 and Regione Campania BURC contract.","Weller D., IEEE Trans. Magn., 39, (2003); Brown W.F., Phys. Rev., 130, (1963); Gardiner C.W., Handbook of Stochastic Methods, (1997); D'Aquino M., Et al., J. Comput. Phys., 209, (2005); Kubo R., Hashitsume N., Suppl. Prog. Theor. Phys., 46, (1970); Fredkin D.R., Physica B, 306, (2001); Garcia-Palacios J., Lazaro F.J., Phys. Rev. B, 58, (1998); Lopez Diaz L., Torres L., Moro E., Phys. Rev. B, 65, (2002); Scholz W., Et al., J. Magn. Magn. Mater., 233, (2001); Milstein G.N., Et al., SIAM (Soc. Ind. Appl. Math.) J. Numer. Anal., 40, (2002); Serpico C., Et al., J. Appl. Phys., 89, (2001)","M. D'Aquino; Department of Electrical Engineering, University of Napoli Federico II, Napoli I-80125, Italy; email: mdaquino@unina.it","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-33646717515" +"Muratov C.B.; Osipov V.V.","Muratov, C.B. (6701461949); Osipov, V.V. (7202505731)","6701461949; 7202505731","Optimal grid-based methods for thin film micromagnetics simulations","2006","Journal of Computational Physics","216","2","","637","653","16","19","10.1016/j.jcp.2005.12.018","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33747029520&doi=10.1016%2fj.jcp.2005.12.018&partnerID=40&md5=8a7e3f0bb812b870ed97b586b3b2340d","Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, United States; Mission Critical Technologies, Inc., El Segundo, CA 90245, 2041 Rosecrans Avenue, Suite 225, United States","Muratov C.B., Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, United States; Osipov V.V., Mission Critical Technologies, Inc., El Segundo, CA 90245, 2041 Rosecrans Avenue, Suite 225, United States","Thin film micromagnetics are a broad class of materials with many technological applications, primarily in magnetic memory. The dynamics of the magnetization distribution in these materials is traditionally modeled by the Landau-Lifshitz-Gilbert (LLG) equation. Numerical simulations of the LLG equation are complicated by the need to compute the stray field due to the inhomogeneities in the magnetization which presents the chief bottleneck for the simulation speed. Here, we introduce a new method for computing the stray field in a sample for a reduced model of ultra-thin film micromagnetics. The method uses a recently proposed idea of optimal finite difference grids for approximating Neumann-to-Dirichlet maps and has an advantage of being able to use non-uniform discretization in the film plane, as well as an efficient way of dealing with the boundary conditions at infinity for the stray field. We present several examples of the method's implementation and give a detailed comparison of its performance for studying domain wall structures compared to the conventional FFT-based methods. © 2006 Elsevier Inc. All rights reserved.","Domain walls; Micromagnetics; Optimal grids; Rational approximations; Stray field","Domain walls; Finite difference method; Magnetic storage; Magnetization; Grid based method; Landau-Lifshitz-Gilbert equations; Magnetic memory; Micromagnetic simulations; Micromagnetics; Optimal grid; Rational approximations; Stray field; Technological applications; Thin-films; Ultrathin films","","","","","National Science Foundation, NSF, (DMS02-11864); National Science Foundation, NSF; National Institutes of Health, NIH, (R01 GM076690); National Institutes of Health, NIH","The authors acknowledge multiple valuable discussions with V. Druskin. The work of CBM was partially supported by NSF via Grant DMS02-11864, and NIH via Grant R01 GM076690.","Hubert A., Schafer R., Magnetic Domains, (1998); Aharoni A., Introduction to the Theory of Ferromagnetism, (1998); Vonsovskii S.V., Ferromagnetism, (1974); Jansen R., Speckmann M., Oepen H.P., van Kempen H., Morphology and magnetism of thin Co films on textured Au surfaces, J. Magn. Magn. Mater., 165, pp. 258-261, (1997); Speckmann M., Oepen H.P., Ibach H., Magnetic domain-structures in ultrathin Co/Au(1 1 1) - on the influence of film morphology, Phys. Rev. Lett., 75, pp. 2035-2038, (1995); Allenspach R., Bischof A., Magnetization direction switching in Fe/Cu(1 0 0) epitaxial-films - temperature and thickness dependence, Phys. Rev. Lett., 69, pp. 3385-3388, (1992); Berger A., Oepen H.P., Magnetic domain walls in ultrathin fcc cobal films, Phys. Rev. B, 45, pp. 12596-12599, (1992); Allenspach R., Stampanoni M., Bischof A., Magnetic domains in thin epitaxial Co/Au(1 1 1) films, Phys. 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Lett., 80, pp. 4281-4284, (1998); Katine J.A., Albert F.J., Buhrman R.A., Meyers E.B., Ralph D.C., Current-driven magnetization reversal and spin-wave excitations in Co/Cu/Co pillars, Phys. Rev. Lett., 84, pp. 3149-3152, (2000); DeSimone A., Kohn R.V., Muller S., Otto F., Magnetic microstructures - a paradigm of multiscale problems, ICIAM 99 (Edinburgh), pp. 175-190, (2000); Gioia G., James R.D., Micromagnetics of very thin films, Proc. Roy. Soc. Lond. Ser. A, 453, pp. 213-223, (1997); Garcia-Cervera C.J., Weinan E., Effective dynamics for ferromagnetic thin films, J. Appl. Phys., 90, pp. 370-374, (2001); Desimone A., Kohn R.V., Muller S., Otto F., A reduced theory for thin-film micromagnetics, Commun. Pure Appl. Math., 55, pp. 1408-1460, (2002); Garcia-Cervera C.J., One-dimensional magnetic domain walls, Euro. J. Appl. Math., 15, pp. 451-486, (2004); Kohn R.V., Slastikov V., Effective dynamics for ferromagnetic thin films: a rigorous justification, Proc. Roy. Soc. Lond. Ser. A, 461, pp. 143-154, (2005); Fidler J., Schrefl T., Micromagnetic modelling - the current state of the art, J. Phys. D, 33, (2000); Yuan S.W., Bertram H.N., Fast adaptive algorithms for micromagnetics, IEEE Trans. Magn., 28, pp. 2031-2036, (1992); Scholz W., Fidler J., Schrefl T., Suess D., Dittrich R., Forster H., Tsiantos V., Scalable parallel micromagnetic solvers for magnetic nanostructures, Comput. Mater. Sci., 28, pp. 366-383, (2003); Trunk T., Redjdal M., Kakay A., Ruane M.F., Hunphrey F.B., Domain wall structure in permalloy films with decreasing thickness at the Bloch to Néel transition, J. Appl. Phys., 89, pp. 7606-7608, (2001); Garcia-Cervera C.J., Gimbutas Z., Weinan E., Accurate numerical methods for micromagnetics simulations with general geometries, J. Comput. Phys., 84, pp. 37-52, (2003); Wang X.P., Garcia-Cervera C.J., Weinan E., A Gauss-Seidel projection method for the Landau-Lifshitz equation, J. Comput. Phys., 171, pp. 357-372, (2001); Tsynkov S.V., Numerical solution of problems on unbounded domains. A review, Appl. Numer. Math., 27, pp. 465-532, (1998); Ingerman D., Druskin V., Knizhnerman L., Optimal finite difference grids and rational approximations of the square root: I. Elliptic problems, Commun. Pure Appl. Math., 53, pp. 1039-1066, (2000); Druskin V., Moscow S., Three-point finite difference schemes, Padé and the spectral Galerkin method. I. One-sided impedance approximation, Math. Comput., 71, pp. 995-1019, (2001); Heinrich B., Cochran J.F., Ultrathin metallic magnetic films: magnetic anisotropies and exchange interactions, Adv. Phys., 42, pp. 523-639, (1993); Taylor M.E., Partial Differential Equations II: Qualitative Studies of Linear Equations, (1996); Petrushev P., Popov V.A., Encyclopedia of Mathematics and Its Applications, 28, (1987); Cheney E.W., Introduction to Approximation Theory. second ed., (1999); Baker G.A., Graves-Morris P., Encyclopedia of Mathematics and Its Applications, 59, (1996)","C.B. Muratov; Department of Mathematical Sciences, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, United States; email: muratov@njit.edu","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","","Scopus","2-s2.0-33747029520" +"Baňas L.","Baňas, L'ubomír (24079505700)","24079505700","Adaptive techniques for Landau-Lifshitz-Gilbert equation with magnetostriction","2008","Journal of Computational and Applied Mathematics","215","2","","304","310","6","12","10.1016/j.cam.2006.03.043","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-40849100575&doi=10.1016%2fj.cam.2006.03.043&partnerID=40&md5=4322e5f426de104fa663c7f022359a05","Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium","Baňas L., Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium","In this paper we propose a time-space adaptive method for micromagnetic problems with magnetostriction. The considered model consists of coupled Maxwell's, Landau-Lifshitz-Gilbert (LLG) and elastodynamic equations. The time discretization of Maxwell's equations and the elastodynamic equation is done by backward Euler method, the space discretization is based on Whitney edge elements and linear finite elements, respectively. The fully discrete LLG equation reduces to an ordinary differential equation, which is solved by an explicit method, that conserves the norm of the magnetization. © 2007 Elsevier B.V. All rights reserved.","Magnetostriction; Maxwell's equations; Micromagnetism; Numerical methods; Space-time a posteriori error estimates","Elastohydrodynamics; Error analysis; Euler equations; Magnetization; Magnetostriction; Maxwell equations; Ordinary differential equations; Problem solving; Adaptive techniques; Elastodynamic equations; Time space adaptive methods; Adaptive algorithms","","","","","IUAP; Universiteit Gent","The work of the author was supported by the IUAP project of Ghent University. He would like to thank Marián Slodička and Roger Van Keer for their stimulation. ","Banas L., Slodicka M., Space discretization for the Landau-Lifshitz-Gilbert equation with magnetostriction, Comput. Meth. Appl. Mech. Eng., 194, 2-5, pp. 467-477, (2005); Beck R., Hiptmair R., Hoppe R.H.W., Wohlmuth B., Residual based a posteriori error estimators for eddy current computation, M2AN Math. Model. Numer. Anal., 34, 1, pp. 159-182, (2000); Bernardi C., Suli E., Time and space adaptivity for the second-order wave equation, Math. Models Methods Appl. Sci., 15, 2, pp. 199-225, (2005); Brenner S.C., Scott L.R., The Mathematical Theory of Finite Element Methods, (1994); Brown Jr. W.F., Magnetoelastic Interactions, (1966); Chen Z., Dai S., Adaptive Galerkin methods with error control for a dynamical Ginzburg-Landau model in superconductivity, SIAM J. Numer. Anal., 38, 6, pp. 1961-1985, (2001); Eriksson K., Johnson C., Adaptive finite element methods for parabolic problems IV: nonlinear problems, SIAM J. Numer. Anal., 32, 6, pp. 1729-1749, (1995); Magni A., Bertotti G., Mayergoyz I.D., Serpico C., Landau-Lifschitz-Gilbert dynamics and eddy current effects in metallic thin films, J. Magn. Magn. Mater., 254-255, pp. 210-212, (2003); Monk P., A posteriori error indicators for Maxwell's equations, J. Comput. Appl. Math., 100, 2, pp. 173-190, (1998); Nocheto R.H., Schmidt A., Verdi C., A posteriori error estimation and adaptivity for degenerate parabolic problems, SIAM J. Numer. Anal., 69, 229, pp. 1-24, (2000); Picasso M., Adaptive finite elements for a linear parabolic problem, Comput. Meth. Appl. Mech. Eng., 167, pp. 223-237, (1998); Schrefl T., Finite elements in numerical micromagnetics part I: granular hard magnets, J. Magn. Magn. Mater., 207, pp. 45-65, (1999); Slodicka M., Banas L., A numerical scheme for a Maxwell-Landau-Lifshitz-Gilbert system, Appl. Math. Comput., 158, 1, pp. 79-99, (2004); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Appl. Numer. Math., 46, 1, pp. 95-111, (2003); Sun J., Collino F., Monk P., Wang L., An eddy-current and micromagnetism model with applications to disk write heads, Internat. J. Numer. Meth. Eng., 60, 10, pp. 1673-1698, (2004); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Japan J. Appl. Math., 2, pp. 69-84, (1985)","L. Baňas; Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium; email: l.banas@imperial.ac.uk","","","","","","","","03770427","","","","English","J. Comput. Appl. Math.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-40849100575" +"Kunz A.","Kunz, Andrew (7005939687)","7005939687","Simulating the maximum domain wall speed in a magnetic nanowire","2006","IEEE Transactions on Magnetics","42","10","","3219","3221","2","24","10.1109/TMAG.2006.880141","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85008013280&doi=10.1109%2fTMAG.2006.880141&partnerID=40&md5=e9c8dc77a81262313ffbd393f16dc2f5","Physics Department, Marquette University, Milwaukee, WI 53201-1881, United States","Kunz A., Physics Department, Marquette University, Milwaukee, WI 53201-1881, United States","The dynamics of domain wall motion in permalloy nanowires have been simulated utilizing the Landau-Lifshitz-Gilbert (LLG) equation of motion. The simulation results are presented in terms of the domain wall speed for ranges of the Gilbert damping parameter alpha and nanowire width. The maximum domain wall speed is independent of alpha. The speed of the domain wall can be increased by increasing the nanowire width, but this lowers the critical field. For applied fields below the critical field, the wall moves uniformly along the wire and the speed of the wall increases with increases in the driving field. This behavior is consistent with current analytic models; however, the models overestimate both the value of the domain wall speed and the critical field. © 2006, IEEE. All rights reserved.","Domain wall dynamics; micromagnetic simulation; nanowires; permalloy","","","","","","Helen Way Klingler College of Arts and Sciences SFF; Marquette University, Marquette","The author would like to thank D. Dahlberg for useful contributions to this work. This work was supported by Marquette University and the Helen Way Klingler College of Arts and Sciences SFF.","Vedmedenko E.Y., Et al., Domain wall orientation in magnetic nanowires, Phys. Rev. Lett., 92, (2004); Atkinson D., Et al., Magnetic domain wall dynamics in a permalloy nanowire, IEEE Trans. Magn., 39, 5, pp. 2663-2665, (2003); Schryer N.L., Walker L.R., The motion of 180° domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, pp. 5406-5421, (1974); Zhu X., Et al., Spatially resolved observation of domain wall propagation in a submicron ferromagnetic NOT-gate, Appl. Phys. Lett., 87, (2005); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, pp. L1-L7, (1996); Thiaville A., Nakatani Y., Miltat J., Vernier N., Domain wall motion by spin-polarized current: A micromagnetic study, J. Appl. Phys., 95, pp. 7049-7051, (2004); Sorop T.G., Et al., Magnetization reversal of ferromagnetic nanowires studied by magnetic force microscopy, Phys. Rev. B., 67, (2003); Nakatani Y., Thiaville A., Miltat J., Faster magnetic walls in rough wires, Nat. Matr., 2, pp. 521-523, (2003); Yamaguchi A., Et al., Real-space observation of current-driven domain wall motion in submicron magnetic wires, Phys. Rev. Lett., 92, (2004); McMichael R.D., Twisselmann D.J., Kunz A., Localized ferromagnetic resonance in inhomogeneous thin films, Phys. Rev. Lett., 90, (2006); Micromagnetic Simulator; Kunz A., Simulated domain wall dynamics in magnetic nanowires, J. Appl. Phys., 99, 08G107, (2006)","","","","","","","","","00189464","","","","English","IEEE Trans Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-85008013280" +"Mojumder N.N.; Augustine C.; Nikonov D.E.; Roy K.","Mojumder, Niladri N. (24067210600); Augustine, Charles (24779266100); Nikonov, Dmitri E. (7003272404); Roy, Kaushik (57000621800)","24067210600; 24779266100; 7003272404; 57000621800","Spin torques estimation and magnetization dynamics in dual barrier resonant tunneling penta-layer magnetic tunnel junctions","2010","Device Research Conference - Conference Digest, DRC","","","5551855","93","94","1","2","10.1109/DRC.2010.5551855","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77957606269&doi=10.1109%2fDRC.2010.5551855&partnerID=40&md5=b9f2887eca2114c471f062342499a13f","School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; Components Research, Intel Corporation, Santa Clara, CA 95052, United States","Mojumder N.N., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; Augustine C., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; Nikonov D.E., Components Research, Intel Corporation, Santa Clara, CA 95052, United States; Roy K., School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States","We investigate electronic transport and magnetization dynamics associated with current induced spin-torque effects in dual barrier magnetic tunnel junctions using Non-Equilibrium Green's Function formalism and Landau-Lifshitz-Gilbert (LLG) equation self-consistently. In a dual barrier penta-layer MTJ, a set of geometry and band-structure parameters including the free-layer thickness, oxide barrier height, width of the tunneling barrier and applied voltage jointly determines the position of resonant peaks and valleys within the energy range of interest. The combined effect of these design parameters to enhance the in-plane and out-of-plane spin-torque efficiencies in both aligned and anti-aligned penta-layer MTJs [Fig. 1] has been studied comprehensively. We quantify the impact of non-monotonic quantum well states for majority and minority spin electrons inside the thin free layer on the spin-torque effects in penta-layer MTJs. We essentially explore the design space for both the aligned and anti-aligned penta-layer MTJs optimized for read/write stabilities, improved TMR and low power. The crucial role of anti-aligned penta-layer MTJs in reducing the Energy-Delay-Product (EDP) during write over tri-layer MTJs has also been reported quantitatively. © 2010 IEEE.","","Green's function; Magnetization; Spin dynamics; Torque; Tunnel junctions; Applied voltages; Barrier heights; Combined effect; Design parameters; Design spaces; Electronic transport; Energy ranges; Energy-delay; Free layers; In-plane; Landau-Lifshitz-Gilbert equations; Layer thickness; Low Power; Magnetic tunnel junction; Magnetization dynamics; Minority spin electrons; Non-equilibrium Green's function formalism; Out-of-plane; Quantum-well state; Resonant peaks; Spin torque; Spin-torque effect; Spin-torque efficiency; Structure parameter; Tunneling barrier; Magnetic devices","","","","","","","Theodonis I., Et al., Journal of Magnetism and Magnetic Materials, 310, 2, pp. 2043-2045, (2007); Li J., Et al., Proc. 45th Design Automation Conf. (DAC 2008), pp. 278-283, (2008)","N. N. Mojumder; School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; email: niladri@ecn.purdue.edu","","","IEEE Electron Devices Society","68th Device Research Conference, DRC 2010","21 June 2010 through 23 June 2010","Notre Dame, IN","81766","15483770","978-142447870-5","","","English","Dev. Res. Conf. Conf. Dig.","Conference paper","Final","","Scopus","2-s2.0-77957606269" +"Serpico C.; Mayergoyz I.D.; Bertotti G.; d'Aquino M.; Bonin R.","Serpico, C. (23013514800); Mayergoyz, I.D. (35495971500); Bertotti, G. (7005370974); d'Aquino, M. (9732823500); Bonin, R. (9736915400)","23013514800; 35495971500; 7005370974; 9732823500; 9736915400","Generalized Landau-Lifshitz-Gilbert equation for uniformly magnetized bodies","2008","Physica B: Condensed Matter","403","2-3","","282","285","3","4","10.1016/j.physb.2007.08.029","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-37349012836&doi=10.1016%2fj.physb.2007.08.029&partnerID=40&md5=c52a1893cd4b05b0b103b6b9a8b5048e","Dipartimento di Ingegneria Elettrica, Università di Napoli FedericoII, I-80125 Napoli, Via Claudio 21, Italy; ECE Department, UMIACS, University of Maryland, College Park, MD 20742, United States; Istituto Nazionale di Ricerca Metrologica (INRiM), I-10135 Torino, Italy; Dipartimento per le Tecnologie, University of Napoli Parthenope, I-80133 Napoli, Italy","Serpico C., Dipartimento di Ingegneria Elettrica, Università di Napoli FedericoII, I-80125 Napoli, Via Claudio 21, Italy; Mayergoyz I.D., ECE Department, UMIACS, University of Maryland, College Park, MD 20742, United States; Bertotti G., Istituto Nazionale di Ricerca Metrologica (INRiM), I-10135 Torino, Italy; d'Aquino M., Dipartimento per le Tecnologie, University of Napoli Parthenope, I-80133 Napoli, Italy; Bonin R., Istituto Nazionale di Ricerca Metrologica (INRiM), I-10135 Torino, Italy","We consider generalized Landau-Lifshitz-Gilbert (LLG) deterministic dynamics in uniformly magnetized bodies. The dynamics take place on the unit sphere Σ, and are characterized by a vector field v tangential to Σ. By using Helmholtz decomposition on Σ, it is proven that v is uniquely defined by two potentials χ and ψ. Potential χ can be identified with the free energy of the system, while ψ describes non-conservative interactions of the system with the environment. The presence of ψ modifies the usual energy balance of LLG dynamics. Instead of purely relaxation dynamics we may have steady injection of energy through non-conservative interactions. The implications of the new form of the energy balance are discussed in detail. © 2007 Elsevier B.V. All rights reserved.","Landau-Lifshitz-Gilbert equation; Micromagnetics; Open systems","Energy conservation; Mathematical models; Open systems; Relaxation processes; Vectors; Landau-Lifshitz-Gilbert equation; Micromagnetics; Vector fields; Magnetization","","","","","MIUR-PRIN, (2006098315)","This work is supported by the Italian MIUR-PRIN Project N.2006098315.","Brown W.F., Micromagnetics, (1963); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, 4, (2001); Perko L., Differential Equations and Dynamical Systems, (1996); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., d'Aquino M., Bonin R., Phys. Rev. Lett., 94, (2005); Wegrowe J.E., Ciornei M.C., Drouhin H.J., J. Phys.: Condens. Matter, 19, (2007)","C. Serpico; Dipartimento di Ingegneria Elettrica, Università di Napoli FedericoII, I-80125 Napoli, Via Claudio 21, Italy; email: serpico@unina.it","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-37349012836" +"Szambolics H.; Buda-Prejbeanu L.D.; Toussaint J.C.; Fruchart O.","Szambolics, H. (23398758300); Buda-Prejbeanu, L.D. (11140986400); Toussaint, J.C. (35502756000); Fruchart, O. (6701577512)","23398758300; 11140986400; 35502756000; 6701577512","Finite element formalism for micromagnetism","2008","COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering","27","1","","266","276","10","1","10.1108/03321640810836825","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-38149034353&doi=10.1108%2f03321640810836825&partnerID=40&md5=4f29b65089bcab655d1639af81483481","Institut Néel, CNRS-INPG-UJF, Grenoble, France; Laboratoire SPINTEC, CEA-CNRS-INPG-UJF, Grenoble, France; Institut National Polytechnique de Grenoble, Grenoble, France","Szambolics H., Institut Néel, CNRS-INPG-UJF, Grenoble, France; Buda-Prejbeanu L.D., Laboratoire SPINTEC, CEA-CNRS-INPG-UJF, Grenoble, France, Institut National Polytechnique de Grenoble, Grenoble, France; Toussaint J.C., Institut Néel, CNRS-INPG-UJF, Grenoble, France, Laboratoire SPINTEC, CEA-CNRS-INPG-UJF, Grenoble, France, Institut National Polytechnique de Grenoble, Grenoble, France; Fruchart O., Institut Néel, CNRS-INPG-UJF, Grenoble, France","Purpose: The aim of this work is to present the details of the finite element approach that was developed for solving the Landau-Lifschitz-Gilbert (LLG) equations in order to be able to treat problems involving complex geometries. Design/methodology/approach: There are several possibilities to solve the complex LLG equations numerically. The method is based on a Galerkin-type finite element approach. The authors start with the dynamic LLG equations, the associated boundary condition and the constraint on the magnetization norm. They derive the weak form required by the finite element method. This weak form is afterwards integrated on the domain of calculus. Findings: The authors compared the results obtained with our finite element approach with the ones obtained by a finite difference method. The results being in very good agreement, it can be stated that the approach is well adapted for 2D micromagnetic systems. Research limitations/implications: The future work implies the generalization of the method to 3D systems. To optimize the approach spatial transformations for the treatment of the magnetostatic problem will be implemented. Originality/value: The paper presents a special way of solving the LLG equations. The time integration a backward Euler method has been used, the time derivative being calculated as a function of the solutions at times n and n+1. The presence of the constraint on the magnetization norm induced a special two-step procedure for the calculation of the magnetization at instant n+1. © Emerald Group Publishing Limited.","Electromagnetism; Finite element analysis; Simulation","Computer simulation; Constraint theory; Finite element method; Galerkin methods; Magnetization; Problem solving; Landau-Lifschitz-Gilbert (LLG) equations; Magnetization norms; Micromagnetic systems; Electromagnetism","","","","","","","Alouges F., Jaisson P., Convergence of a finite elements discretization for Landau-Lifschitz equations, Mathematical Models and Methods in Applied Sciences, 16, 2, pp. 299-313, (2006); Braess D., Finite Elements, (2001); Brown W.F., Micromagnetics, (1963); Brunotte X., Meunier G., Imhoff J.-F., Finite modeling of unbounded problems using transformations, IEEE Transactions on Magnetics, 28, pp. 1663-1666, (1992); Garcia-Cervera C.J., Gimbutas Z., Weinan E., Accurate numerical methods for micromagnetics simulations with general geometries, Journal of Computational Physics, 184, pp. 37-52, (2003); Jubert P.O., Fruchart O., Meyer C., Self-assembled growth of faceted epitaxial Fe (110) islands on Mo (110)/Al2O3 , Physical Review B, 64, pp. 115419-115428, (2001); Li S., Peyrade D., Natali M., Lebib A., Chen Y., Ebels U., Buda L.D., Ounadjela K., Flux closure structures in cobalt rings, Physical Review Letters, 86, pp. 1102-1105, (2001); Toussaint J.C., Marty A., Vukadinovic N., Ben Youssef J., Labrune M., A new technique for ferromagnetic resonance calculations, Computational Materials Science, 24, pp. 175-180, (2002)","H. Szambolics; Institut Néel, CNRS-INPG-UJF, Grenoble, France; email: helga.szambolics@grenoble.cnrs.fr","","Emerald Group Publishing Ltd.","","","","","","03321649","","CODUD","","English","COMPEL Int J Comput Math Electr Electron Eng","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-38149034353" +"Weisheit M.; Fähler S.; Bonfim M.; Grechishkin R.; Barthem V.; Givord D.","Weisheit, M. (6602003138); Fähler, S. (8264158400); Bonfim, M. (6701832890); Grechishkin, R. (6602116569); Barthem, V. (6602736160); Givord, D. (7006566630)","6602003138; 8264158400; 6701832890; 6602116569; 6602736160; 7006566630","Magnetization Reversal of Highly Coercive FePt Examined With Pulsed Microcoils","2006","IEEE Transactions on Magnetics","42","10","","3072","3074","2","14","10.1109/TMAG.2006.880146","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85008066058&doi=10.1109%2fTMAG.2006.880146&partnerID=40&md5=b6a8776d00940c0895fdd5c650173a41","IFW Dresden, Institute for Metallic Materials, D-01069, Dresden, Germany; Centro Politécnico, PR, CEP 81531-990, CP 19011 Curitiba, Brazil; Department of Physics, Tver State University, 170000, Tver, Russian Federation; Universidade Federal do Rio de Janeiro, Instituto de Física, 21941-972 Rio de Janeiro, Sala CT A-451, Brazil; Laboratoire Louis Neel, 38042 Grenoble Cedex 9, France","Weisheit M., IFW Dresden, Institute for Metallic Materials, D-01069, Dresden, Germany; Fähler S., IFW Dresden, Institute for Metallic Materials, D-01069, Dresden, Germany; Bonfim M., Centro Politécnico, PR, CEP 81531-990, CP 19011 Curitiba, Brazil; Grechishkin R., Department of Physics, Tver State University, 170000, Tver, Russian Federation; Barthem V., Universidade Federal do Rio de Janeiro, Instituto de Física, 21941-972 Rio de Janeiro, Sala CT A-451, Brazil; Givord D., Laboratoire Louis Neel, 38042 Grenoble Cedex 9, France","The switching of ultra-high coercivity FePt thin films has been studied by pulsed magnetic fields of up to 25 T, generated with microcoils of 50 μm diameter and using a fast magneto-optical polar Kerr effect setup. Whereas under static measurements, the coercive field reaches 5.5 T, under pulsed magnetic field it approaches 8 T. An approximation of the Landau-Lifshitz-Gilbert (LLG) equation was used to calculate the magnetization response to the field pulse. Good agreement between experiment and simulation is observed if a value of 0.1 is assumed for the damping constant. © 2006, IEEE. All rights reserved.","FePt; hard magnetic thin films; L10; magnetic fields; magnetic films; magnetization reversal; magneto-optic Kerr effect; perpendicular magnetic anisotropy; pulsed magnetic fields","","","","","","","","Sun S., Murray C.B., Weller D., Folks L., Moser A., Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices, Science, pp. 1989-1992, (2000); Shima T., Takanashi K., Takahashi Y.K., Hono K., Coercivity exceeding 100 kOe in epitaxially grown FePt sputtered films, Appl. Phys. Lett, 13, pp. 2571-2573, (2004); Weisheit M., Schultz L., Fahler S., Textured growth of highly coercive L10 ordered FePt thin films on single crystalline and amorphous substrates, J. Appl. Phys, 11, pp. 7489-7491, (2004); Okamoto S., Kitakami O., Kikuchi N., Miyazaki T., Shimada Y., Takahashi Y.K., Size dependences of magnetic properties and switching behavior in FePt L10 nanoparticles, Phys. Rev. B, 9, (2003); Neudert A., McCord J., Chumakov D., Schafer R., Schultz L., Small-amplitude magnetization dynamics in permalloy elements investigated by time-resolved wide-field kerr microscopy, Phys. Rev. B (Condensed Matter and Materials Physics), 13, (2005); Back C.H., Weller D., Heidmann J., Mauri D., Guarisco D., Garwin E.L., Siegmann H.C., Magnetization reversal in ultrashort field pulses, Phys. Rev. Lett., 81, pp. 3251-3254, (1998); Mackay K., Bonfim M., Givord D., Fontaine A., 50 T pulsed magnetic fields in microcoils, J. Appl. Phys, 4, pp. 1996-2002, (2000); Bonfim M., Mackay K., Pizzini S., Arnou M.-L., Fontaine A., Ghiringhelli G., Pascarelli S., Neisius T., Nanosecond resolved techniques for dynamical magnetization reversal measurements, J. Appl. Phys, 9, pp. 5974-5976, (2000); Klemmer T., Hoydick D., Okumura H., Zhang B., Soffa W.A., Magnetic hardening and coercivity mechanisms in L10 ordered FePd ferromagnets, Scr. Metall. Mater., 33, (1995)","","","","","","","","","00189464","","","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85008066058" +"Hinata S.; Saito S.; Hasegawa D.; Takahashi M.","Hinata, Shintaro (26531433400); Saito, Shin (55155900000); Hasegawa, Daiji (8510385900); Takahashi, Migaku (7406845773)","26531433400; 55155900000; 8510385900; 7406845773","Q-band ferromagnetic resonance for CoPt-based stacked perpendicular recording media with interlayer exchange coupling","2011","Journal of Applied Physics","109","8","083935","","","","11","10.1063/1.3569843","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79955742171&doi=10.1063%2f1.3569843&partnerID=40&md5=1f6f4cd74945b093fe95c2df5606c8b3","Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Japan; Waseda Institute for Advanced Study, Waseda University, Shinjuku-ku, Tokyo 169-8050, 1-6-1 Nishi Waseda, Japan","Hinata S., Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Japan; Saito S., Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Japan; Hasegawa D., Waseda Institute for Advanced Study, Waseda University, Shinjuku-ku, Tokyo 169-8050, 1-6-1 Nishi Waseda, Japan; Takahashi M., Waseda Institute for Advanced Study, Waseda University, Shinjuku-ku, Tokyo 169-8050, 1-6-1 Nishi Waseda, Japan","The ferromagnetic interlayer exchange coupling Jinter for stacked perpendicular recording media with a granular layer (GL)/interlayer (IL)/alloy capping layer (CL) structure was quantitatively evaluated by Q-band ferromagnetic resonance (FMR). Two resonances with acoustic and optical precession modes were observed in the FMR signals from the stacked media. Fitting using the Landau-Lifshitz-Gilbert (LLG) equation indicated that J inter increased from 0.55 to 1.83 erg/cm2 when the Pt IL thickness was reduced from 2.0 to 1.0 nm for media based on Co 82Cr10Pt8-CL (4 nm) and Co74Pt 16Cr10-8 mol (SiO2)-GL (16 nm). The optimum Pt IL thickness at which the switching field distribution was minimized due to a large reduction in the saturation field of the stacked media was found to correspond to the boundary condition between antiparallel and parallel precession of the magnetic moments of the GL and CL in FMR. © 2011 American Institute of Physics.","","Exchange coupling; Ferromagnetic materials; Ferromagnetism; Magnetic moments; Multilayers; Platinum; Platinum alloys; Resonance; Silicon compounds; Capping layer; Ferromagnetic interlayers; Granular layer; Interlayer exchange coupling; Landau-Lifshitz-Gilbert equations; Perpendicular recording media; Saturation fields; Switching field distribution; Ferromagnetic resonance","","","","","Japan Society for the Promotion of Science, JSPS, (10J02544); New Energy and Industrial Technology Development Organization, NEDO; New Energy and Industrial Technology Development Organization, NEDO"," We would like to thank Professor Dr. Nobuyuki Inaba from Yamagata University for valuable discussion on the linewidths of FMR signals. This study was partially supported by Industrial Technology Research Grant Program in 2006 from New Energy and Industrial Technology Development Organization (NEDO) of Japan. ","Choe G., Zheng M., Acharya B.R., Abarra E.N., Zhou J.N., Perpendicular recording CoPtCrO composite media with performance enhancement capping layer, IEEE Transactions on Magnetics, 41, 10, pp. 3172-3174, (2005); Shimatsu T., Inaba Y., Watanabe S., Kitakami O., Okamoto S., Aoi H., Muraoka H., Nakamura Y., Recording resolution and writability for (Co-Pt)-SiO2/Co- SiO2 hard/soft-stacked granular perpendicular media, IEEE Transactions on Magnetics, 43, 6, pp. 2103-2105, (2007); Sonobe Y., Weller D., Ikeda Y., Takano K., Schabes M.E., Zeltzer G., Do H., Yen B.K., Best M.E., Coupled granular/continuous medium for thermally stable perpendicular magnetic recording, Journal of Magnetism and Magnetic Materials, 235, 1-3, pp. 424-428, (2001); Sonobe Y., Muraoka H., Miura K., Nakamura Y., Takano K., Do H., Moser A., Yen B.K., Ikeda Y., Supper N., Coupled granular/continuous perpendicular recording media with soft magnetic underlayer, Journal of Applied Physics, 91, 10 III, (2002); Muraoka H., Sonobe Y., Miura K., Goodman A.M., Nakamura Y., Analysis on magnetization transition of CGC perpendicular media, IEEE Transactions on Magnetics, 38, 4 I, pp. 1632-1636, (2002); Zhang Z., Zhou L., Wigen P.E., Phys. Rev. B, 50, (1994); Lindner J., Baberschke K., J. Phys.: Condens. Mat., 15, (2003); Hinata S., Saito S., Takahashi M., J. Magn. Soc. Jpn., 34, (2010); Suzuki M., Miyagawa H., Kawamura N., Muraoka H., Inaba Y., Shimatsu T., Sonobe Y., Isohama Y., Nakamura N., Ishimatsu N., Maruyama H., Magnetic moment in the top Pt layer of Co/Pt bilayers, Physica Scripta T, T115, pp. 580-582, (2005); Kittel C., Phys. Rev., 73, (1948); Saito S., Hasegawa D., Hoshi F., Djayaprawira D.D., Takahashi M., Quantitative evaluation of magnetocrystalline anisotropy of columnar grains and thickness of initial layer in CoCr-based perpendicular media, Applied Physics Letters, 80, 5, (2002); Zoll S., Dinia A., Stoeffler D., Gester M., Den Berg H.A.M.V., Ounadjela K., Europhys. Lett., 39, (1997); Zeper W.B., Greidanus F.J.A.M., Carcia P.F., Fincher C.R., J. Appl. Phys., 65, (1989); Lin C.-J., Gorman G.L., Lee C.H., Farrow R.F.C., Marinero E.E., Do H.V., Notarys H., Chien C.J., Magnetic and structural properties of Co/Pt multilayers, Journal of Magnetism and Magnetic Materials, 93, pp. 194-206, (1991); Zhang Z., Wigen P.E., Parkin S.S.P., J. Appl. Phys., 69, (1994); Nemoto H., Hosoe Y., Analysis of interfacial magnetic anisotropy in Co/Pt and Co/Pd multilayer films, Journal of Applied Physics, 97, 10, pp. 1-3, (2005); Tham K.K., Saito S., Hasegawa D., Itagaki N., Hinata S., Takahashi M., Digests of the Perpendicular Magnetic Recording Conference, 124, (2010)","S. Hinata; Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, 6-6-05, Aoba, Japan; email: s_hinata@ecei.tohoku.ac.jp","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-79955742171" +"Mojumder N.N.; Augustine C.; Roy K.","Mojumder, Niladri N. (24067210600); Augustine, Charles (24779266100); Roy, Kaushik (57000621800)","24067210600; 24779266100; 57000621800","Self-consistent transport-magnetic simulation and benchmarking of hybrid spin-torque driven Magnetic Tunnel Junctions (MTJs)","2010","Biennial University/Government/Industry Microelectronics Symposium - Proceedings","","","5508921","","","","1","10.1109/UGIM.2010.5508921","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77955734240&doi=10.1109%2fUGIM.2010.5508921&partnerID=40&md5=e4b389c33c3c49204f3ca80bcdc05474","Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States","Mojumder N.N., Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; Augustine C., Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; Roy K., Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States","We investigate electronic transport and magnetization dynamics associated with the current induced spin torque effects in two different classes of magnetic tunnel junctions using Non-Equilibrium Green's Function (NEGF) formalism and Landau-Lifshitz-Gilbert (LLG) equation. We calibrate our transport simulation framework with a diverse set of tri-layer experiments, before we proceed with dual barrier penta-layer MTJ simulations. We investigate and thereby compare the magnetization switching dynamics of a tri-layer with that of an anti-aligned penta-layer MTJ corresponding to parallel (P) to anti-parallel (AP) switching and vice versa. Higher critical switching current density (JC) and asymmetric switching characteristics have been confirmed for tri-layer structures as opposed to the case of identical anti-aligned penta-layer configurations. Energy efficiency of anti-aligned penta-layer over that of tri-layer MTJ structures during spin torque driven magnetization switching has also been reported quantitatively. ©2010 IEEE.","NEGF; Spin-torque transfer; STT-MRAM; Tunneling Magneto-Resistance (TMR)","Energy efficiency; Green's function; Magnetic field effects; Magnetization; Magnetoresistance; Magnetos; Switching; Torque; Tunnel junctions; Critical switching current; Electronic transport; Landau-Lifshitz-Gilbert equations; Layer configuration; Magnetic simulation; Magnetic tunnel junction; Magnetization dynamics; Magnetization switching; NEGF; Non-equilibrium Green's function; Spin torque; Spin-torque effect; STT-MRAM; Switching characteristics; Transport simulation; Trilayer structure; Tunneling Magneto-Resistance (TMR); Spin dynamics","","","","","","","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Slonczewski J.C., Sun J.Z., Theory of voltage-driven current and torque in magnetic tunnel junctions, Journal of Magnetism and Magnetic Materials, 310, 2 PART 1, pp. 169-175; Fuchs G.D., Krivorotov I.N., Braganca P.M., Emley N.C., Garcia A.G.F., Ralph D.C., Buhrman R.A., Adjustable spin torque in magnetic tunnel junctions with two fixed layers, Appl. Phys. Lett., 86, (2005); Diao Z., Panchula A., Ding Y., Pakala M., Wang S., Li Z., Apalkov D., Nagai H., Driskill-Smith A., Wang L.-C., Chen E., Huai Y., Spin transfer switching in dual MgO magnetic tunnel junctions, Appl. Phys. Lett., 90, (2007); Finocchio G., Azzerboni B., Fuchs G.D., Buhrman R.A., Torres L., Micromagnetic modeling of magnetization switching driven by spin-polarized current in magnetic tunnel junctions, J. Appl. Phys., 101, (2007); Datta S., Electronic Transport in Mesoscopic Systems, (1995); Uemura T., Marukame T., Yamamoto M., Proposal and analysis of a ferromagnetic triple-barrier resonant-tunneling spin filter, Magnetics, IEEE Transactions on, 39, 5, pp. 2809-2811, (2003); Vedyayev A., Ryzhanova N., Dieny B., Strelkov N., Phys. Lett. A, 355, (2006); Theodonis I., Kalitsov A., Kioussis N., Spin transfer torque in double barrier magnetic tunnel junctions, Journal of Magnetism and Magnetic Materials, 310, 2 PART 3, pp. 2043-2045, (2007); Datta S., Quantum Transport: Atom to Transistor, (2005); Anantram M.P., Lundstrom M.S., Nikonov D.E., Modeling of Nanoscale Devices, Proceedings of the IEEE, 96, 9, pp. 1511-1550, (2008); Salahuddin S., Datta D., Datta S., Spin Transfer Torque As a Non-conservative Pseudo-Field, (2008); Salahuddin S., Datta D., Srivastava P., Datta S., Quantum transport in Spin Torque Transfer devices, Bulletin of the American Physical Society: Proc. 2008 March Meeting, 53, 2, (2008); Kurniawan O., Bai P., Li E., Ballistic calculation of nonequilibrium Green's function in nanoscale devices using finite element method, J. Phys. D: Appl. Phys., 42, (2009); Salahuddin S., Et al., Quantum Transport Simulation of Tunneling Based Spin Torque Transfer (STT) Devices: Design Trade-offs and Torque Efficiency, IEDM Tech. Dig., pp. 121-124, (2007); Yanik A., Klimeck G., Datta S., Quantum transport with spin dephasing: A nonequlibrium Green's function approach, Phys. Rev. B, 76, (2007); Miltat J., Albuquerque G., Thiaville A., An Introduction to Micromagnetics in the Dynamic Regime, Spin Dynamics in Confined Magnetic Structures I, Topics Appl. Phys., 83, pp. 1-34, (2002); Salahuddin S., Datta S., Self-consistent simulation of hybrid spintronic devices, 2006 Intl. Electron Devices Meeting (IEDM '06) Technical Digest, (2006); Sankey J.C., Cui Y.-T., Sun J.Z., Slonczewski J.C., Buhrman R.A., Ralph D.C., Nat. Phys., 4, (2008); Yuasa S., Nagahama T., Fukushima A., Suzuki Y., Ando K., Nat. Mater., 3, (2004); Li J., Augustine C., Salahuddin S., Roy K., Modeling of failure probability and statistical design of Spin-Torque Transfer Magnetic Random Access Memory (STT MRAM) array for yield enhancement, Proc. 45th Design Automation Conf. (DAC 2008), pp. 278-283, (2008); Hosomi M., Et al., Novel nonvolatile memory with spin torque transfer magnetization switching: Spin-ram, IEDM Tech. Dig., pp. 459-462, (2005); Datta S., Proc. Int. Sch. Phy.,Enrico Fermi, Italy, (2005)","N. N. Mojumder; Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, United States; email: niladri@ecn.purdue.edu","","","IEEE","18th Biennial University/Government/Industry Micro-Nano Symposium, UGIM 2010","28 June 2010 through 1 July 2010","West Lafayette, IN","81415","07496877","978-142444732-9","","","English","Bien Univ Gov Ind Microelectr Symp Proc","Conference paper","Final","","Scopus","2-s2.0-77955734240" +"Kavitha L.; Sathishkumar P.; Gopi D.","Kavitha, L. (6507907076); Sathishkumar, P. (57009164700); Gopi, D. (59157674200)","6507907076; 57009164700; 59157674200","Shape changing soliton in a site-dependent ferromagnet using tanh-function method","2009","Physica Scripta","79","1","015402","","","","33","10.1088/0031-8949/79/01/015402","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-66149108045&doi=10.1088%2f0031-8949%2f79%2f01%2f015402&partnerID=40&md5=f933ef1ef3e9f791e498188a48c621c0","Department of Physics, Periyar University, Salem 636 011, India; Department of Chemistry, Periyar University, Salem 636 011, India","Kavitha L., Department of Physics, Periyar University, Salem 636 011, India; Sathishkumar P., Department of Physics, Periyar University, Salem 636 011, India; Gopi D., Department of Chemistry, Periyar University, Salem 636 011, India","The dynamics of an inhomogeneous (site-dependent) Heisenberg ferromagnetic spin chain with Gilbert damping is expressed in the form of the Landau-Lifshitz-Gilbert (LLG) equation in the classical continuum limit. By stereographic projection of the unit sphere of spin onto a complex plane, we rewrite the LLG equation in terms of the stereographic variable ω(x,t). Using the modified extended tanh-function method with the aid of symbolic computation the exact spin soliton solution is constructed. The effect of inhomogeneity and damping on the spin soliton is studied. © 2009 The Royal Swedish Academy of Sciences.","","Damping; Ferromagnetic materials; Ferromagnetism; Solitons; Complex planes; Continuum limits; Ferromagnet; Ferromagnetic spin chains; Gilbert damping; Heisenberg; Inhomogeneity; Landau-Lifshitz-Gilbert equations; LLG equation; Spin solitons; Stereographic projection; Symbolic computation; Tanh-function method; Spin dynamics","","","","","","","De Gasperis P., Marcelli R., Miccoli G., Phys. Rev. Lett., 59, 4, (1987); Slavin A.N., Rojdestvenski I.V., IEEE Trans. Magn., 30, 1, (1994); Daniel M., Kavitha L., Phys. Rev., 63, 17, (2001); Daniel M., Kavitha L., Amudha R., Phys. Rev., 59, 21, (1999); Bass F.G., Nasonov N.N., Naumenko O.V., Sov. Phys. Tech. Phys., 33, (1988); Ablowitz M.J., Clarkson P.A., Solitons, Nonlinear Evolution Equations and Inverse Scattering, (1991); Vakhnenko V.O., Parkes E.J., Morrison A.J., Chaos Solitons Fractals, 17, 4, (2003); Wadati M., Sanuki H., Konno K., Prog. Theor. Phys., 53, 2, (1967); Gardner C.S., Green J.M., Kruskal M.D., Miura R.M., Phys. Rev. Lett., 19, 19, (1967); Hirota R., Phys.Rev. Lett., 27, 18, (1971); Tsigaridas G., Fragos A., Polyzos I., Fakis M., Ioannou A., Giannetas V., Persephonis P., Chaos Solitons Fractals, 23, 5, (2005); Zhang H.-Q., Li J., Xu T., Zhang Y.-X., Hu W., Tian B., Phys. Scr., 76, 5, (2007); Banerjee R.S., Phys. Scr., 57, 5, (1998); Dehghan M., Shakeri F., Phys. Scr., 75, 6, (2007); He J., Phys. Scr., 76, 6, (2007); Chen J.-L., Dai C., Phys. Scr., 77, 2, (2008); Bekir A., Phys. Scr., 77, 4, (2008); Wazwaz A.-M., Commun. Nonlinear Sci. Numer. Simul., 11, 2, (2006); Dai C.-Q., Wang Y., Phys. Scr., 78, 1, (2008); Yan Z., Phys. Scr., 78, 3, (2008); Wang Q., Chen Y., Chaos Solitons Fractals, 31, 2, (2007); Zhao X., Zhi H., Zhang H., Chaos Solitons Fractals, 28, 1, (2006); Sheng Z., Chaos Solitons Fractals, 32, 4, (2007); Yan Z., Zhang H., Phys. Lett., 285, 5-6, (2001); Junqi H., Chaos Solitons Fractals, 23, 2, (2005); Irk D., Dag D., Phys. Scr., 77, 6, (2008); El-Wakil S.A., Abdou M.A., Chaos Solitons Fractals, 31, 5, (2007); El-Wakil S.A., Abdou M.A., Chaos Solitons Fractals, 31, 4, (2007); El-Wakil S.A., Abdou M.A., Nonlinear Anal., 68, 2, (2008); Wazwaz A.M., Appl. Math. Comput., 154, 3, (2004); Pal D., Golam Ali S.K., Talukdar B., Phys. Scr., 77, 6, (2008); Kavitha L., Daniel M., J. Phys. A Math. Gen., 36, 42, (2003); Daniel M., Lakshmanan M., Physica, 120, 1-2, (1983); Lakshmanan M., Daniel M., Physica, 107, 3, (1981); Rosenfeld B.A., Sergeeva N.D., Stereographic Projection, (1977); Ibrahim R.S., El-Kalaawy O.H., Chaos Solitons Fractals, 31, 4, (2007); Bai C., Zhao H., Chaos Solitons Fractals, 27, 4, (2006); Daniel M., Kavitha L., Phys. Rev., 66, 18, (2002); Amuda R., Phys. Scr., 73, 3, (2006)","L. Kavitha; Department of Physics, Periyar University, Salem 636 011, India; email: louiskavitha@yahoo.co.in","","","","","","","","14024896","","PHSTB","","English","Phys Scr","Article","Final","","Scopus","2-s2.0-66149108045" +"Chubykalo-Fesenko O.; Nowak U.; Chantrell R.W.; Garanin D.","Chubykalo-Fesenko, O. (8264321700); Nowak, U. (7003770249); Chantrell, R.W. (7102157314); Garanin, D. (7006641565)","8264321700; 7003770249; 7102157314; 7006641565","Dynamic approach for micromagnetics close to the Curie temperature","2006","Physical Review B - Condensed Matter and Materials Physics","74","9","094436","","","","161","10.1103/PhysRevB.74.094436","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33749256853&doi=10.1103%2fPhysRevB.74.094436&partnerID=40&md5=911cb3c8a661dedf628c1c7c9ce8ed51","Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain; Department of Physics, University of York, York YO10 5DD, United Kingdom; Department of Physics and Astronomy, Lehman College, City University of New York, Bronx, NY 10468-1589, 250 Bedford Park Boulevard West, United States","Chubykalo-Fesenko O., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain; Nowak U., Department of Physics, University of York, York YO10 5DD, United Kingdom; Chantrell R.W., Department of Physics, University of York, York YO10 5DD, United Kingdom; Garanin D., Department of Physics and Astronomy, Lehman College, City University of New York, Bronx, NY 10468-1589, 250 Bedford Park Boulevard West, United States","In conventional micromagnetism magnetic domain configurations are calculated based on a continuum theory for the magnetization. This theory assumes that the absolute magnetization value is constant in space and time. Dynamics is usually described with the Landau-Lifshitz-Gilbert (LLG) equation, the stochastic variant of which includes finite temperatures. Using simulation techniques with atomistic resolution we show that this conventional micromagnetic approach fails for higher temperatures since we find two effects which cannot be described in terms of the LLG equation: (i) an enhanced damping when approaching the Curie temperature and, (ii) a magnetization magnitude that is not constant in time. We show, however, that both of these effects are naturally described by the Landau-Lifshitz-Bloch equation which links the LLG equation with the theory of critical phenomena and turns out to be a more realistic equation for magnetization dynamics at elevated temperatures. © 2006 The American Physical Society.","","","","","","","","","Van Kampen M., Jozsa C., Kohlhepp J.T., Leclair P., Lagae L., De Jonge W.J.M., Koopmans B., Phys. Rev. Lett., 88, (2002); Beaurepaire E., Merle J.-C., Daunois A., Bigot J.Y., Phys. Rev. Lett., 76, (1996); Safonov V.L., Bertram H.N., J. Appl. Phys., 87, (2000); Feng X., Visscher P.B., J. Appl. Phys., 89, (2001); Lyberatos A., Berkov D.V., Chantrell R.W., J. Phys.: Condens. Matter, 5, (1993); Grinstein G., Koch R.H., Phys. Rev. Lett., 90, (2003); Kirschner M., Schrefl T., Dorfbauer F., Hrkac G., Suess D., Fidler J., J. Appl. Phys., 97, (2005); Garcia-Sanchez F., Chubykalo-Fesenko O., Mryasov O., Chantrell R.W., Yu. Guslienko K., Appl. Phys. Lett., 87, (2005); Kronmuller H., Fischer R., Hertel R., Leineweber T., J. Magn. Magn. Mater., 177, (1997); Dobrovitski V.V., Katsnelson M.I., Harmon B.N., Phys. Rev. Lett., 90, (2003); Lyberatos A., Yu. Guslienko K., J. Appl. Phys., 94, (2003); Nowak U., Mryasov O.N., Wieser R., Guslienko K., Chantrell R.W., Phys. Rev. B, 72, (2005); Garanin D.A., Ishchenko V.V., Panina L.V., Theor. Math. Phys., 82, (1990); Garanin D.A., Phys. Rev. B, 55, (1997); Kotzler J., Garanin D.A., Hartl M., Jahn L., Phys. Rev. Lett., 71, (1993); Kazantseva N., Wieser R., Nowak U., Phys. Rev. Lett., 94, (2005); Li Y., Baberschke K., Farle M., J. Appl. Phys., 69, (1991); Chen K., Landau D.P., Phys. Rev. B, 49, (1993); Garanin D.A., Chubykalo-Fesenko O., Phys. Rev. B, 70, (2004)","","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-33749256853" +"Mills D.L.; Arias R.","Mills, D.L. (14319237900); Arias, Rodrigo (7006356208)","14319237900; 7006356208","The damping of spin motions in ultrathin films: Is the Landau-Lifschitz-Gilbert phenomenology applicable?","2006","Physica B: Condensed Matter","384","1-2","","147","151","4","29","10.1016/j.physb.2006.05.209","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33748206740&doi=10.1016%2fj.physb.2006.05.209&partnerID=40&md5=c71313f5d5f33999c1ebe66077f311bc","Department of Physics and Astronomy, University of California, Irvine, CA 92697, 4129 Frederick Reines Hall, United States; Departamento de Física, FCFM, Universidad de Chile, Santiago, Casilla 487-3, Chile","Mills D.L., Department of Physics and Astronomy, University of California, Irvine, CA 92697, 4129 Frederick Reines Hall, United States; Arias R., Departamento de Física, FCFM, Universidad de Chile, Santiago, Casilla 487-3, Chile","The Landau-Lifschitz-Gilbert (LLG) equation is used widely in device design to describe spin motions in magnetic nanoscale structures. The damping term in this equation plays an essential role in the description of the magnetization dynamics. The form of this term is simple and appealing, but it is derived through use of elementary phenomenological considerations. An important question is whether or not it provides a proper description of the damping of the magnetization in real materials. Recently, it was predicted that a mechanism called two magnon damping should contribute importantly to linewidths and consequently spin damping in ultrathin ferromagnetic films. This process yields ferromagnetic resonance (FMR) linewidths whose frequency dependence is incompatible with the linear variation expected from the Landau-Lifschitz equation. This prediction has now been confirmed experimentally. Furthermore, subsequent experimental and theoretical studies have demonstrated that the damping rate depends strongly on wave vector as well. It is thus clear that for many samples, the LLG equation fails to account for the systematics of the damping of the magnetization in ultrathin ferromagnets, at the linear response level. The paper will review the recent literature on this topic relevant to this issue. One must then inquire into the nature of a proper phenomenology to describe these materials. At the linear response level, the theory of the two magnon mechanism is sufficiently complete that one can describe the response of these systems without resort to LLG phenomenology. However, currently there is very great interest in the large amplitude response of the magnetization in magnetic nanostructures. In the view of the authors, it is difficult to envision a generally applicable extension of linear response theory into the large amplitude regime. © 2006.","Damping; Ferromagnetic; Films; Landau-Lifschitz-Gilbert; Two magnon","Damping; Equations of motion; Ferromagnetic materials; Ferromagnetic resonance; Magnetic films; Magnetization; Landau-Lifschitz-Gilbert equations; Magnetic nanoscale structures; Magnon damping; Spin motions; Ultrathin films","","","","","US DOD, (W911NF-04-1-0247)","This research was supported by US DOD Grant no. W911NF-04-1-0247.","Kuanr B., Celinsky Z., Camley R.E., Appl. Phys. Lett., 3969, (2003); Arias R., Mills D.L., Phys. Rev. B, 60, (1999); Arias R., Mills D.L., J. Appl. Phys., 87, (2001); Mills D.L., Rezende S.M., Spin Dynamics in Confined Magnetic Structures II, (2003); Heinrich B., Ultrathin Magnetic Structures II, (1994); LeCraw R.C., Spencer E.G., Porter C.S., Phys. Rev., 122, (1958); Sparks M., Loudon R., Kittel C., Phys. Rev., 122, (1961); Rezende S.M., Azevedo A., Lucena M.A., Aquiar F.M., Phys. Rev. B, 63, (2001); Urban R., Woltersdorf G., Heinrich B., Phys. Rev. Lett., 87, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. B, 66, (2002); Zwierzycki M., Tserkovnyak Y., Kelly P.J., Brataas A., Bauer G.E.W., Phys. Rev. B, 71, (2005); Simanek E., Heinrich B., Phys. Rev. B, 67, (2003); Simanek E., Phys. Rev. B, 68, (2003); Mills D.L., Phys. Rev. B, 68, (2003); Costa A.T., Muniz R.B., Mills D.L., Phys. Rev. B, 73, (2006); Lindner J., Lenz K., Kosubek E., Baberschke K., Spodding D., Meckenstock R., Pelzl J., Frait Z., Mills D.L., Phys. Rev. B, 68, (2003); Woltersdorf G., Heinrich B., Phys. Rev. B, 69, (2004)","D.L. Mills; Department of Physics and Astronomy, University of California, Irvine, CA 92697, 4129 Frederick Reines Hall, United States; email: dlmills@uci.edu","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-33748206740" +"Karakurt S.; Chantrell R.W.; Nowak U.","Karakurt, S. (16506512500); Chantrell, R.W. (7102157314); Nowak, U. (7003770249)","16506512500; 7102157314; 7003770249","A model of damping due to spin-lattice interaction","2007","Journal of Magnetism and Magnetic Materials","316","2 SPEC. ISS.","","e280","e282","2","10","10.1016/j.jmmm.2007.02.118","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34250307940&doi=10.1016%2fj.jmmm.2007.02.118&partnerID=40&md5=80db373c1ac6ae6315fa3475f2dbccb8","University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom","Karakurt S., University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom; Chantrell R.W., University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom; Nowak U., University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom","The dynamic behavior of a spin magnetic moment is often described in terms of the Landau-Lifschitz-Gilbert (LLG) equation. This contains two terms, the first describing the precession of the spin, and the second providing a damping of the precessional motion. Whereas the precession part is well understood at a fundamental level, only an intuitive knowledge of the damping term exists. The damping term represents the interaction between the spin system and the heat bath, and is included in a phenomenological way in the LLG equation. In order to understand the latter mechanism at a more basic level, we have developed a model in which the heat bath variables are introduced explicitly, with the damping introduced by a term which couples the spins to the heat bath. Specifically, we solve two sets of coupled dynamical equations, one representing the spin dynamics, and the second the underlying mechanical oscillations of the lattice. The former consists of the precessional term only, while for the latter we use a Brownian Dynamic approach, which excites the phonon modes of the lattice. The equations are solved numerically to give the time evolution of the magnetization. It is found that, although in principle the coupling mechanism does not affect the motion of the FMR (k=0) mode, damping of this mode does appear due to non-linearities which scatter energy into magnon modes with non-zero k. We demonstrate that the model gives results similar in form to the LLG equation, i.e. a damped precessional motion of the magnetization into the local field direction. We also present the results of a study of finite size effects, which shows that the effective damping constant is dependent on the system size because of changes in the phonon spectrum. © 2007 Elsevier B.V. All rights reserved.","Damping; Ferromagnetic insulator; Nanoparticle; Relaxation","Damping; Dynamical systems; Magnetic moments; Magnetization; Phonons; Systems analysis; Ferromagnetic insulators; Finite size effects; Heat bath; Landau-Lifschitz-Gilbert (LLG) equation; Magnon modes; Mathematical models","","","","","","","Gilbert T., IEEE Trans. Magn., 40, (2004); Sparks M., Ferromagnetic Relaxation Theory, (1964); Gurevich, Melkov G.A., Magnetization Oscillation and Waves, (1996); L Safonov V.L., Neal Bertram H., Phys. Rev. B, 61, (2000); Nowak U., Thermally activated reversal in magnetic nanostructures, Ann. Rev. Comp. Phys., 9, (2001); Li Y., Baberschke K., Farle M., J. Appl. Phys., 69, (1991)","S. Karakurt; University of York, Department of Physics, Heslington, York, YO10 5DD, United Kingdom; email: sk509@york.ac.uk","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-34250307940" +"D'Aquino M.; Serpico C.; Miano G.; Bertotti G.","D'Aquino, Massimiliano (9732823500); Serpico, Claudio (23013514800); Miano, Giovanni (7006758103); Bertotti, Giorgio (7005370974)","9732823500; 23013514800; 7006758103; 7005370974","Computation of resonant modes and frequencies for saturated ferromagnetic nanoparticles","2008","IEEE Transactions on Magnetics","44","11 PART 2","","3141","3144","3","7","10.1109/TMAG.2008.2001602","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-65249152813&doi=10.1109%2fTMAG.2008.2001602&partnerID=40&md5=3dbfffd835628524446f1f118ac05c72","Department of Technology, University of Naples Parthenope, Naples 80143, Italy; Department of Electrical Engineering, University of Naples Federico II, Naples 80125, Italy; Istituto Nazionale di Ricerca Metrologica (INRiM), Turin 10135, Italy","D'Aquino M., Department of Technology, University of Naples Parthenope, Naples 80143, Italy; Serpico C., Department of Electrical Engineering, University of Naples Federico II, Naples 80125, Italy; Miano G., Department of Electrical Engineering, University of Naples Federico II, Naples 80125, Italy; Bertotti G., Istituto Nazionale di Ricerca Metrologica (INRiM), Turin 10135, Italy","The free oscillations of a micromagnetic system around a saturated equilibrium are considered. Magnetization dynamics is described by the Landau-Lifshitz-Gilbert (LLG) equation. The LLG equation is linearized around the equilibrium and put in the form of a generalized eigenvalue problem for suitable self-adjoint operators connected to the micromagnetic effective field. The spectral properties of this problem are studied. The spatial discretization of the problem is analyzed and numerical computation of the resonant oscillations for a magnetic thin-film are performed. © 2008 IEEE.","Ferromagnetic resonance; Generalized eigenvalue problem; Normal modes; Resonant frequencies","Ferromagnetic materials; Ferromagnetic resonance; Ferromagnetism; Magnetic thin films; Natural frequencies; Ferromagnetic nanoparticles; Generalized eigenvalue problems; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Normal modes; Numerical computations; Self adjoint operator; Spatial discretizations; Eigenvalues and eigenfunctions","","","","","MIUR-PRIN, (2006098315)","ACKNOWLEDGMENT This work was supported by the Italian MIUR-PRIN under Project N. 2006098315.","Walker L.R., Phys. Rev. 1bf, 105, (1957); Aharoni A., J. Appl. Phys., 69, (1991); Brown Jr. W.F., Micromagnetics, (1963); Toussaint J.C., Et al., Comput. Mater. Sci., 24, (2002); McMichael R.D., Et al., J. Appl. Phys., 97, (2005); Grimsditch M., Et al., Phys. Rev. B., 69, (2004); Labbe S., Et al., J. Magn. and Magn. Mater., 206, (1999); D'Aquino M., Et al., Physica B., 403, (2008); Kato T., Perturbation Theory for Linear Operators, (1980); Schabes M.E., Et al., IEEE Trans. Magn., 23, (1987); LAPACK User's Guide","M. D'Aquino; Department of Technology, University of Naples Parthenope, Naples 80143, Italy; email: daquino@uniparthenope.it","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-65249152813" +"Kageyama Y.; Suzuki T.","Kageyama, Y. (56217046400); Suzuki, T. (24516104700)","56217046400; 24516104700","Temperature dependence of magnetic properties in single crystal particles of cobalt","2007","Journal of Magnetism and Magnetic Materials","310","2 SUPPL. PART 3","","e789","e791","2","5","10.1016/j.jmmm.2006.11.084","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33847638067&doi=10.1016%2fj.jmmm.2006.11.084&partnerID=40&md5=926701a8faa804d652b03f59a8ae4f31","Information Storage Materials Laboratory, Toyota Technological Institute, Tempaku, Nagoya, Aichi, 468-8511, 2-12-1, Hisakata, Japan","Kageyama Y., Information Storage Materials Laboratory, Toyota Technological Institute, Tempaku, Nagoya, Aichi, 468-8511, 2-12-1, Hisakata, Japan; Suzuki T., Information Storage Materials Laboratory, Toyota Technological Institute, Tempaku, Nagoya, Aichi, 468-8511, 2-12-1, Hisakata, Japan","Single crystal Co films (19-220 nm in thickness with their c-axis parallel to the surface normal) were epitaxially deposited onto Al2O3(0 0 over(1, -)) single-crystal substrates by electron beam evaporation, and from these films, Co particles with diameters of 0.5, 1, and 2.5 μm were fabricated by electron beam lithography and Ar ion beam etching. Magnetic domain structures of the films and the particles were observed by magnetic force microscopy (MFM) with temperature up to 200 °C. For the 220 nm thick sample's case, maze patterns in domain structure were clearly observed both in the film and the particles. MFM images taken at elevated temperatures do not show drastic change in the domain patterns. On the other hand, for the 56 nm thick sample's case, maze-type domain structure in the original film turns to concentric-type structure after patterning into particles, and furthermore, the domain structure exhibits vortex at 200 °C. Landau-Lifshitz-Gilbert (LLG) simulation for domain pattern visualization was also conducted, and the results show good agreement with experimental results of the 220 nm thick samples, though for the 56 nm sample's case the agreement is not so satisfactory. © 2006 Elsevier B.V. All rights reserved.","Cobalt; Landau-Lifshitz-Gilbert equation; Magnetic domain pattern; Magnetic property; MFM; Single crystal","Aluminum compounds; Electron beam lithography; Magnetic domains; Magnetic force microscopy; Magnetic properties; Metallic films; Single crystal surfaces; Thermal effects; Electron beam evaporation; Landau-Lifshitz-Gilbert equations; Magnetic domain patterns; Cobalt","","","","","","","Takahashi M., Suzuki T., Jpn. J. Appl. Phys., 18, (1979); Kageyama Y., Suzuki T., J. Appl. Phys., 99, (2006)","Y. Kageyama; Information Storage Materials Laboratory, Toyota Technological Institute, Tempaku, Nagoya, Aichi, 468-8511, 2-12-1, Hisakata, Japan; email: kageyama@mosk.tytlabs.co.jp","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-33847638067" +"Itoh A.; Itoh Y.; Nanba K.; Adachi Y.; Motohashi M.; Tsukamoto A.","Itoh, Akiyoshi (7202208783); Itoh, Yujii (55423239500); Nanba, Kensuke (7103105290); Adachi, Yoshiharu (13606594200); Motohashi, Masataka (36843586000); Tsukamoto, Arata (9736764300)","7202208783; 55423239500; 7103105290; 13606594200; 36843586000; 9736764300","Cu doping effect on FePt grains prepared by rapid thermal annealing on SiO2 substrate and wall structure in TbFeCo/FePt CGC-like film","2006","Journal of Applied Physics","99","8","08Q906","","","","3","10.1063/1.2170055","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33646752141&doi=10.1063%2f1.2170055&partnerID=40&md5=50ee68e157e17ffcf9f3bf790eb8a57d","College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197, 10-1 Morinosato-Wakamiya, Japan; Graduate School of Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan","Itoh A., College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; Itoh Y., Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197, 10-1 Morinosato-Wakamiya, Japan; Nanba K., Graduate School of Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; Adachi Y., Graduate School of Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; Motohashi M., Graduate School of Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; Tsukamoto A., College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan","We report that Cu substitution is effective in raising the degree of (001) crystal orientation of FePt grains prepared by rapid thermal annealing on SiO2. We fabricated coupled granular and continuous (CGC) like films such as TbFeCo on FePt grains. The wall coercivity was about twice that of the TbFeCo single layer film. From three-dimensional micromagnetic simulations with Landau-Lifshitz-Gilbert (LLG) equation, it was confirmed that wall coercivity was enhanced and domain shapes made smooth in CGC film. When the thickness of the TbFeCo layer was thin, wall width was thinner than the theoretical value. © 2006 American Institute of Physics.","","Coercive force; Computer simulation; Copper compounds; Differential equations; Platinum compounds; Rapid thermal annealing; Semiconductor doping; Coupled granular and continuous (CGC); Landau-Lifshitz-Gilbert (LLG) equation; Micromagnetic simulations; TbFeCo layer; Iron compounds","","","","","Ministry of Education, Culture, Sports, Science and Technology, MEXT, (16360182)","This work is partially supported by a Grant-in-Aid for Scientific Research of the Ministry of Education, Culture, Sports, Science and Technology of Japan, Grant No. 16360182.","Sun S., Murray C.B., Weller D., Folksand L., Moser A., Science, 287, (2000); Zeng H., Yan M.L., Powers N., Sellmyer D.J., Appl. Phys. Lett., 80, (2002); Maeda T., Kai T., Kikitsu A., Nagase T., Akiyama J., Appl. Phys. Lett., 80, (2002); Itoh Y., Aoyagi A., Tsukamoto A., Nakagawa K., Itoh A., Jpn. J. Appl. Phys., Part 1, 43, (2004); Hashida N., Kato T., Iwata S., Tsunashima S., J. Magn. Soc. Jpn., 24, (2000)","A. Itoh; College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, 7-24-1 Narashino-dai, Japan; email: aitoh@ecs.cst.nihon-u.ac.jp","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-33646752141" +"Kong D.; Chen C.; He L.","Kong, Desheng (56380939800); Chen, Chinping (34874487700); He, Lin (57199954428)","56380939800; 34874487700; 57199954428","Collective magnetization flux closure state with circular array of single-domained nanomagnets: Magnetization reversal and chirality control","2008","Journal of Applied Physics","103","11","114312","","","","7","10.1063/1.2937253","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-45149119940&doi=10.1063%2f1.2937253&partnerID=40&md5=d58619cddf01c8225e470b8d047239cc","Department of Physics, Peking University, Beijing 100871, China","Kong D., Department of Physics, Peking University, Beijing 100871, China; Chen C., Department of Physics, Peking University, Beijing 100871, China; He L., Department of Physics, Peking University, Beijing 100871, China","A practical approach is theoretically proposed for the formation and manipulation of the chirality of a magnetization flux closure (MFC) state. It is realizable over a circular array consisting of a few single-domained (SD) nanomagnets. The entire array size is smaller than 100 nm. The investigation is performed by numerical calculations based on the Landau-Lifshitz-Gilbert equation. Parameters concerning the formation and stability of the MFC state are obtained for the circular arrays of five and six nanomagnets. The effect of the applied field orientation on the manipulation of the chirality is investigated. In addition, the critical distance LC is determined, beyond which the effect of magnetic coupling between adjacent arrays becomes negligible. The corresponding maximum density of arrays without the magnetic coupling effect is thus estimated. Our work makes the application of the collective MFC state in the ultrahigh density magnetic storage possible, exceeding 200 Gbits in2. © 2008 American Institute of Physics.","","Chirality; Enantiomers; Ferromagnetism; Local area networks; Magnetization; Magnetization reversal; Magnets; Manipulators; Microbial fuel cells; Numerical analysis; Stereochemistry; Applied fields; chirality control; circular arrays; Circular arrays (CA); Collective magnetization; Critical distances; Landau Lifshitz Gilbert (LLG) equations; Magnetization flux; Nano-magnets; Numerical calculations; Practical approach; Magnetism","","","","","Fostering Talents of Basic Science, (NFFTBS-J0630311)"," This work is supported, in part, by the National Fund for Fostering Talents of Basic Science (NFFTBS-J0630311). ","Shinjo T., Okuno T., Hassdorf R., Shigeto K., Ono T., Science, 289, (2000); Wachowiak A., Wiebe J., Bode M., Pietzsch O., Morgenstern M., Wiesendanger R., Science, 298, (2002); Choe S.-B., Acremann Y., Scholl A., Bauer A., Doran A., Stohr J., Padmore H.A., Science, 304, (2004); Waeyenberge B.V., Puzic A., Stoll H., Chou K.W., Tyliszczak T., Hertel R., Fahnle M., Bruckl H., Rott K., Reiss G., Neudecker I., Weiss D., Back C.H., Schutz G., Nature (London), 444, (2006); Yamada K., Kasal S., Nakatani Y., Kobayashi K., Kohno H., Thiaville A., Ono T., Nat. Mater., 6, (2007); Prinz G.A., Science, 282, (1998); Vavassori P., Grimsditch M., Metlushko V., Zaluzec N., Ilic B., Appl. Phys. Lett., 86, (2005); Kimura T., Otani Y., Hamrle J., Appl. Phys. Lett., 87, (2005); Jung W., Castao F.J., Ross C.A., Phys. Rev. Lett., 97, (2006); Klaui M., Rothman J., Lopez-Diaz L., Vaz C.A.F., Bland J.A.C., Cui Z., Appl. Phys. Lett., 78, (2001); Schneider M., Hoffmann H., Zweck J., Appl. Phys. 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Mater., 309, (2007); Lifshitz E.M., Pitaevskii L.P., Course of Theoretical Physics, 5, (1980); Black C.T., Murray C.B., Sandstrom R.L., Sun S., Science, 290, (2000); Skomski R., J. Phys.: Condens. Matter, 15, (2003); Novosad V., Guslienko K.Yu., Shima H., Otani Y., Kim S.G., Fukamichi K., Kikuchi N., Kitakami O., Shimada Y., Phys. Rev. B, 65, (2002); Zhu J.-G., Zheng Y., Prinz G.A., J. Appl. Phys., 87, (2000); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. Lett., 83, (1999)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-45149119940" +"Guo J.; Jalil M.B.A.; Tan S.G.","Guo, Jie (55709457700); Jalil, Mansoor Bin Abdul (7006821429); Tan, Seng Ghee (8571745900)","55709457700; 7006821429; 8571745900","Current-induced magnetization excitation in a pseudo-spin-valve with in-plane anisotropy","2008","Applied Physics Letters","92","18","182103","","","","3","10.1063/1.2919734","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-43349084918&doi=10.1063%2f1.2919734&partnerID=40&md5=d73abd6f7abdf66302fd8f41babc8f25","Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Data Storage Institute, DSI Building, National University of Singapore, Singapore 117608, 5 Engineering Drive 1, Singapore","Guo J., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Tan S.G., Data Storage Institute, DSI Building, National University of Singapore, Singapore 117608, 5 Engineering Drive 1, Singapore","We study the magnetization dynamics of a pseudo-spin-valve structure with in-plane anisotropy, which is induced by the passage of a perpendicular-to-plane spin-polarized current. The magnetization dynamics is described by a modified Landau-Lifshitz-Gilbert (LLG) equation, which incorporates two spin torque terms. The simulation results reveal two magnetization excitation modes: (a) complete magnetization reversal and (b) persistent spin precession. The existence of these dual modes may be explained in terms of the competition between the four terms of the modified LLG equation. Our results give indications to the optimal operating conditions for current-induced magnetization dynamics for possible device applications. © 2008 American Institute of Physics.","","Anisotropy; Computer simulation; Magnetoelectronics; Spin dynamics; Landau-Lifshitz-Gilbert (LLG) equations; Magnetization dynamics; Spin precession; Magnetization reversal","","","","","National University of Singapore, NUS, (R-263-000-481-112)","This work was supported by the National University of Singapore under Grant R-263-000-481-112.","Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Urazhdin S., Birge N.O., Pratt Jr. W.P., Bass J., Appl. Phys. Lett., 84, (2004); Fuchs G.D., Emley N.C., Krivorotov I.N., Braganca P.M., Ryan E.M., Kiselev S.I., Sankey J.C., Ralph D.C., Buhrman R.A., Appl. Phys. Lett., 85, (2004); Manschot J., Brataas A., Bauer G.E.W., Appl. Phys. Lett., 85, (2004); Jiang Y., Nozaki T., Abe S., Ochiai T., Hirohata A., Tezuka N., Inomata K., Nat. Mater., 3, (2004); Mangin S., Ravelosona D., Katine J.A., Carey M.J., Terris B.D., Fullerton E.E., Nat. Mater., 5, (2006); Houssameddine D., Ebels U., Delat B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Cyrille M.-C., Redon O., Dieny B., Nat. Mater., 6, (2007); Seki T., Mitani S., Yakushiji K., Takanashi K., Appl. Phys. Lett., 88, (2006); Sort J., Garcia F., Auffret S., Rodmacq B., Dieny B., Langlais V., Suriach S., Muoz J.S., Baro M.D., Nogus J., Appl. Phys. Lett., 87, (2005); Guo J., Jalil M.B.A., Phys. Rev. B, 71, (2005); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Stiles M.D., Saslow W.M., Donahue M.J., Zangwill A., Phys. Rev. B, 75, (2007); Zimmler M.A., Ozyilmaz B., Chen W., Kent A.D., Sun J.Z., Rooks M.J., Koch R.H., Phys. Rev. B, 70, (2004); Donahue M., Porter D.; Covington M., Science, 307, (2005); Sun J., Nature (London), 425, (2003); Meng H., Wang J.-P., Appl. Phys. Lett., 88, (2006); pp. 266-274, (2006); Visscher P.B., Apalkov D.M., J. Appl. Phys., 97, (2005); Chen Y.F., Ziese M., Esquinazi P., Appl. Phys. Lett., 88, (2006); Wang X.R., Sun Z.Z., Phys. Rev. Lett., 98, (2007)","J. Guo; Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; email: elegj@nus.edu.sg","","","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-43349084918" +"Tutu H.; Horita T.","Tutu, Hiroki (6603211752); Horita, Takehiko (7005933018)","6603211752; 7005933018","Stochastic Landau-Lifshitz-Gilbert equation with delayed feedback field","2008","Progress of Theoretical Physics","120","2","","315","345","30","3","10.1143/PTP.120.315","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-56349130089&doi=10.1143%2fPTP.120.315&partnerID=40&md5=60ebf1adc85f37362207e19bb40e8aae","Department of Applied Analysis and Complex Dynamical Systems, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan; Department of Mathematical Sciences, Osaka Prefecture University, Sakai 599-8531, Japan","Tutu H., Department of Applied Analysis and Complex Dynamical Systems, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan; Horita T., Department of Mathematical Sciences, Osaka Prefecture University, Sakai 599-8531, Japan","A time-delayed feedback control to stabilize a swinging motion of magnetic moment in a single-domain magnetic system under AC field is studied. The system has a uniaxial anisotropy, and the AC field is parallel to this. Without control, it prefers the Ising state that is (anti)parallel to the anisotropy axis. The control stabilizes the oscillation across the equatorial plane perpendicular to the anisotropy axis (swinging motion). Employing a stochastic Landau-Lifshitz-Gilbert (LLG) equation, we study the effects of thermal fluctuation on the controlled state. Linear fluctuation, in which variance linearly depends on noise intensity, around the controlled state is analyzed in terms of correlation function and spectral density, and a criterion for the existence of such a linear relationship is obtained. Several technical improvements in the treatment of the stochastic LLG equation and the corresponding Fokker-Planck equation with stereographic coordinate system are also shown.","","","","","","","","","Pyragas K., Phys. Lett. A, 170, (1992); Handbook of Chaos Control, (2007); Tutu H., Prog. Theor. Phys, 116, (2006); Brown G., Novotny M.A., Rikvold P.A., Phys. Rev. B, 64, (2001); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Tome T., de Oliveira M.J., Phys. Rev. A, 41, (1990); Lakshmanan M., Nakamura K., Phys. Rev. Lett, 53, (1984); Ruemelin W., SIAM Journal on Numerical Analysis, 19, (1984); Matsumoto M., Nishimura T., ACM Trans, on Modeling and Computer Simulation, 8, (1998); McNamara B., Wiesenfeld K., Phys. Rev. A, 39, (1989); Gammaitoni L., Hanggi P., Jung P., Marchesoni F., Rev. Mod. Phys, 70, (1998); Brown J.W.F., Phys. Rev, 130, (1963); Kubo R., Hashitsume N., Prog. Theor. Phys. Suppl. No, 46, (1970); Guillouzic S., L'Heureux I., Longtin A., Phys. Rev. E, 59, (1999); Frank T.D., Phys. Rev. E, 66, (2002); Frank T.D., Phys. Rev. E, 71, (2005); Gardiner C.W., Handbook of stochastic methods: For physics, chemistry and the natural science, (1997); Kuchler U., Mensch B., Stoch. Stoch. Rep, 40, (1992); Tsimring L.S., Pikovsky A., Phys. Rev. Lett, 87, (2001)","H. Tutu; Department of Applied Analysis and Complex Dynamical Systems, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan; email: tutu@acs.i.kyotou.ac.jp","","","","","","","","13474081","","","","English","Prog. Theor. Phys.","Article","Final","","Scopus","2-s2.0-56349130089" +"Chen W.; Han M.; Deng L.","Chen, Wenbing (56092812000); Han, Mangui (15759475100); Deng, Longjiang (15070111700)","56092812000; 15759475100; 15070111700","High frequency microwave absorbing properties of cobalt nanowires with transverse magnetocrystalline anisotropy","2010","Physica B: Condensed Matter","405","6","","1484","1488","4","56","10.1016/j.physb.2009.12.026","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-76349123812&doi=10.1016%2fj.physb.2009.12.026&partnerID=40&md5=b7269444e798ee02624ddb3151bb25c3","State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China","Chen W., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; Han M., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; Deng L., State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China","Cobalt nanowires with transverse magnetocrystalline anisotropy have been fabricated and the dynamic permittivity and permeability spectra of the nanowire/paraffin composite were measured in the frequency range of 0.5-18 GHz. The imaginary part of the permeability spectra for the nanowire/paraffin composite samples exhibits a strong absorption peak at 6.1 GHz and two minor peaks at above 10 GHz. It is determined that the peak at 6.1 GHz is attributed to the natural resonance mechanism and the other two peaks are caused by eddy current effect. The permeability spectra attributed to natural resonance are fitted using the LLG equation and further confirmed by calculation based on the Kittel formula. The electromagnetic wave reflection loss values of the nanowire/paraffin composite sample are lower than -20 dB when the thickness of the nanowire/paraffin composite is adjusted, suggesting that the cobalt nanowire composites are promising candidates as microwave absorbers. © 2009 Elsevier B.V. All rights reserved.","Cobalt nanowire; Microwave absorption; Permeability spectra","Absorption; Capillarity; Cobalt; Electromagnetic waves; Magnetocrystalline anisotropy; Microwaves; Resonance; Absorption peaks; Composite samples; Eddy-current effects; Frequency ranges; High frequency; Imaginary parts; LLG equation; Microwave absorbers; Microwave absorbing properties; Microwave absorption; Nanowire composites; Natural resonance; Permeability spectrum; Nanowires","","","","","","","Han M., Deng L.J., Appl. Phys. Lett., 90, (2007); Han M., Ou Y., Liang D.F., Deng L.J., Chinese. Phys. B, 18, (2009); Zhang X.F., Dong X.L., Huang H., Liu Y.Y., Lv B., Lei J.P., Choi C.J., J. Phys. D Appl. Phys., 40, (2007); Ghasemi A., Hossienpour A., Morisako A., Liu X., Ashrafizadeh A., Mater. Design, 29, (2008); Feng Y.B., Qiu T., Shen C.Y., J. Magn. Magn. Mater., 318, (2007); Sugimoto S., Haga K., Kagotani T., Inomata K., J. Magn. Magn. Mater., 290, (2005); Lin H., Zhu H., Guo H., Yu L., Mater. Lett., 61, (2007); Xu P., Han X.J., Liu X.R., Zhang B., Wang C., Wang X.H., Mater. Chem. Phys., 114, (2009); Zhang L., Zhu H., Song Y., Zhang Y., Huang Y., Mater. Sci. Eng. B, 153, (2008); Cao M.S., Shi X.L., Fang X.Y., Jin H.B., Hou Z.L., Zhou W., Chen Y.J., Appl. Phys. Lett, 91, (2007); Chen Y.J., Cao M.S., Wang T.H., Wan Q., Appl. Phys. Lett., 84, (2004); Mu G., Chen N., Pan X., Yang K., Gu M., Appl. Phys. Lett., 91, (2007); Zhou K.S., Xia H., Huang K.L., Deng L.W., Wang D., Zhou Y.P., Gao S.H., Physica B, 404, (2009); Encinas A., Vila L., Darques M., George J.M., Piraux L., Nanotechnology, 18, (2007); Darques M., Piraux L., Encinas A., Bayle-Guillemaud P., Popa A., Ebels U., Appl. Phys. Lett., 86, (2005); Li D.D., Thompson R.S., Bergmann G., Lu J.G., Adv. Mater., 20, (2008); Encinas-Oropesa A., Demand M., Piraux L., Huynen I., Ebels U., Phys. Rev. B, 63, (2001); Fang J.X., Yin Z.W., Physics of Dielectric Materials, (2000); Wu J., Kong L., Appl. Phys. Lett., 84, (2004); Liao S.B., Ferromagnetism, (1998); Wu M.Z., Zhang Y.D., Hui S., Xiao T.D., Ge S.H., Hines W.A., Budnick J.I., Taylor G.W., Appl. Phys. Lett., 80, (2002); Kittel C., Phys. Rev., 73, (1948)","M. Han; State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China; email: mangui@gmail.com","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-76349123812" +"d'Aquino M.; Serpico C.; Miano G.","d'Aquino, Massimiliano (9732823500); Serpico, Claudio (23013514800); Miano, Giovanni (7006758103)","9732823500; 23013514800; 7006758103","Geometrical integration of Landau-Lifshitz-Gilbert equation based on the mid-point rule","2005","Journal of Computational Physics","209","2","","730","753","23","110","10.1016/j.jcp.2005.04.001","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-21444450553&doi=10.1016%2fj.jcp.2005.04.001&partnerID=40&md5=cf97fd6c2d1cc3a832b3e08f8f775c64","Department of Electrical Engineering, University of Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy","d'Aquino M., Department of Electrical Engineering, University of Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy; Serpico C., Department of Electrical Engineering, University of Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy; Miano G., Department of Electrical Engineering, University of Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy","Landau-Lifshitz-Gilbert (LLG) equation is the fundamental equation to describe magnetization vector field dynamics in microscale and nanoscale magnetic systems. This equation is highly nonlinear in nature and, for this reason, it is generally solved by using numerical techniques. In this paper, the mid-point rule time-stepping technique is applied to the numerical time integration of LLG equation and the relevant properties of the numerical scheme are discussed. The mid-point rule is an unconditionally stable and second order accurate scheme which preserves the fundamental geometrical properties of LLG dynamics. First, it exactly preserves the LLG property of conserving the magnetization magnitude at each spatial location. Second, for constant in time applied fields, it preserves the LLG Lyapunov structure, namely the fact that the free energy is a decreasing function of time. In addition, in the case of zero damping, the mid-point rule preserves the conservation of the system free energy. The above preservation properties are unconditionally valid, i.e. they are fulfilled for any value of the time-step. Finally, the LLG hamiltonian structure in the case of zero damping is preserved up to the third order terms with respect to the time-step. The main difficulty related to this scheme is the necessity of solving a large system of globally coupled nonlinear equations. This problem has been circumvented by using special and reasonably fast quasi-Newton iterative technique. The proposed numerical scheme is then tested on the standard micromagnetic problem no. 4. In the numerical computations, the spatial discretization is obtained by finite difference technique and the magnetostatic field is computed through the Fast Fourier Transform method. © 2005 Elsevier Inc. All rights reserved.","Geometric integration; Implicit methods; Landau-Lifshitz-Gilbert equation; Micromagnetic standard problems; Micromagnetics; Mid-point rule","Damping; Fast Fourier transforms; Free energy; Geometry; Hamiltonians; Integral equations; Iterative methods; Magnetostatics; Nanomagnetics; Nonlinear equations; Numerical methods; Geometric integration; Implicit methods; Landau-Lifshitz-Gilbert; Landau-Lifshitz-Gilbert equations; Micromagnetic standard problem; Micromagnetics; Mid-point rule; Property; Standard problems; Magnetization","","","","","MIUR-FIRB","This work is partially supported by the Italian MIUR-FIRB under contract no. RBAU01B2T8 and by ISI Lagrange Fellow Program. ","Aharoni A., Introduction to the Theory of Ferromagnetism, (2001); Albuquerque G., Miltat J., Thiaville A., Self-consistency based control scheme for magnetization dynamics, J. Appl. Phys., 89, (2001); Austin M.A., Krishnaprasad P.S., Almost Poisson integration of rigid body systems, J. Comput. Phys., 107, (1993); Baibich M.N., Broto J.M., Fert A., Nguyen Van Dau F., Petroff F., Etienne P., Creuzet G., Friederich A., Chazelas J., Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices, Phys. Rev. Lett., 61, pp. 2472-2475, (1988); Berkov D.V., Ramstock K., Hubert A., Solving micromagnetic problems: Towards an optimal numerical method, Phys. Status Solidi A, 137, (1993); Bertotti G., Hysteresis in Magnetism, (1998); Bertotti G., Serpico C., Mayergoyz I.D., Nonlinear magnetization dynamics under circularly polarized field, Phys. Rev. Lett., 86, (2001); Binasch G., Gruenberg P., Saurenbach F., Zinn W., Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange, Phys. Rev. B, 39, pp. 4828-4830, (1989); Bloch A., Krishnaprasad P.S., Marsden J.E., Ratiu T.S., The Euler-Poincaré equations and double bracket dissipation, Commun. Math. Phys., 175, pp. 1-42, (1996); Brown Jr. W.F., Micromagnetics, (1963); Budd C.J., Piggott M.D., Geometric integration and its applications, (2001); Channell P.J., Scovel J.C., Symplectic integration of Hamiltonian systems, Nonlinearity, 3, pp. 231-259, (1990); Daniel M., Amuda R., Nonlinear dynamics of weak ferromagnetic spin chains, J. Phys. A: Math. Gen., 28, pp. 5529-5537, (1995); Daughton J.M., Magnetoresistive Random Access Memory (MRAM) Technology, (2000); Fidler J., Schrefl T., Micromagnetic modelling - The current state of the art, J. Phys. D: Appl. Phys., 33, (2000); Gilbert T.L., A Lagrangian formulation of the gyromagnetic equation of the magnetic field, Phys. Rev., 100, (1955); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Kantorovich L.V., Akilov G.P., Functional Analysis, (1982); Kikuchi R., On the minimum of magnetization reversal time, J. Appl. Phys., 27, (1956); Krishnaprasad P.S., Tan X., Cayley transforms in micromagnetics, Physica B, 306, (2001); Lewis D., Nigam N., Geometric integration on spheres and some interesting applications, J. Comput. Appl. Math., 151, (2003); Liu C.S., Lie symmetry of the Landau-Lifshitz-Gilbert equation and exact linearization in the Minkowski space, Z. Angew. Math. Phys., 55, pp. 606-625, (2004); Landau D.P., Krech M., Spin dynamics simulations of classical ferro- and antiferromagnetic model systems: Comparison with theory and experiment, J. Phys.: Condens. Matter, 11, (1999); Mallinson J.C., Damped gyromagnetic switching, IEEE Trans. Magn., 36, (2000); Marsden J.E., Ratiu T.S., Introduction to Mechanics and Symmetry, (1999); Monk P.B., Vacus O., Error estimates for a numerical scheme for ferromagnetic problems, SIAM J. Numer. Anal., 36, 3, pp. 696-718, (1998); Monk P.B., Vacus O., Accurate discretization of a nonlinear micromagnetic problem, Comput. Methods Appl. Mech. Eng., 190, 40-41, pp. 5243-5269, (2001); Ortega J.M., Rheinboldt W.C., Iterative solution of nonlinear equations in several variables, (2000); Podio-Guidugli P., On dissipation mechanisms in micromagnetics, Eur. Phys. J. B, 19, (2001); Prohl A., Computational micromagnetism, volume xvi of Advances in numerical mathematics, (2001); Saad Y., Schultz M.H., GMRES: A generalized minimal residual algorithm for solving nonsymmetric linear systems, SIAM J. Sci. Statist. Comput., 7, 3, (1986); Safonov V.L., Bertram H.N., Intrinsic mechanism of nonlinear damping in magnetization reversal, J. Appl. Phys., 87, (2000); Schabes M.E., Aharoni A., Magnetostatic interaction fields for a three-dimensional array of ferromagnetic cubes, IEEE Trans. Magn., 23, 6, (1987); Scholz W., (2003); Serpico C., Mayergoyz I.D., Bertotti G., Analytical solutions of Landau-Lifshitz equation for precessional switching, J. Appl. Phys., 93, (2003); Serpico C., Mayergoyz I.D., Bertotti G., Numerical technique for integration of the Landau-Lifshitz equation, J. Appl. Phys., 89, (2001); Slodiccka M., Banas L., A numerical scheme for a Maxwell-Landau-Lifshitz-Gilbert system, Appl. Math. Comput., 158, pp. 79-99, (2004); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Appl. Numer. Math., 46, 1, pp. 95-111, (2003); Spargo A.W., Ridley P.H.W., Roberts G.W., Geometric integration of the Gilbert equation, J. Appl. Phys., 93, (2003); Wang D., Tondra M., Pohm A.V., Nordman C., Anderson J., Daughton J.M., Black W.C., Spin dependent tunneling devices fabricated for magnetic random access memory applications using latching mode, J. Appl. Phys., 87, 9, (2000); Wang X., Garcia-Cervera C.J., Weinan E., A Gauss-Seidel projection method for micromagnetics simulations, J. Comput. Phys., 171, pp. 357-372, (2001); Weller D., Assault on storage density of 1 Terabit/sq-in and beyond, Plenary Lecture at JEMS'04 Conference, (2004); Wigen P.E., Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Yuan S.W., Neal H., Bertram, Fast adaptive algorithms for micromagnetics, IEEE Trans. Magn., 28, (1992)","M. d'Aquino; Department of Electrical Engineering, University of Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy; email: mdaquino@unina.it","","Academic Press Inc.","","","","","","00219991","","JCTPA","","English","J. Comput. Phys.","Article","Final","","Scopus","2-s2.0-21444450553" +"Huber A.","Huber, Alexander (36650723500)","36650723500","Periodic solutions for the Landau-Lifshitz-Gilbert equation","2011","Journal of Differential Equations","250","5","","2462","2484","22","6","10.1016/j.jde.2010.11.019","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-78651516132&doi=10.1016%2fj.jde.2010.11.019&partnerID=40&md5=422a6bac3c6824383f2056dd442d5be9","NWF I-Mathematik, Universität Regensburg, 93040 Regensburg, Germany","Huber A., NWF I-Mathematik, Universität Regensburg, 93040 Regensburg, Germany","Ferromagnetic materials tend to develop very complex magnetization patterns whose time evolution is modeled by the so-called Landau-Lifshitz-Gilbert equation (LLG). In this paper, we construct time-periodic solutions for LLG in the regime of soft and small ferromagnetic particles which satisfy a certain shape condition. Roughly speaking, it is assumed that the length of the particle is greater than its hight and its width. The approach is based on a perturbation argument and the spectral analysis of the corresponding linearized problem as well as the theory of sectorial operators. © 2010 Elsevier Inc.","Continuation method; Landau-Lifshitz-Gilbert equation; Micromagnetism; Sectorial operators; Spectral analysis; Time-periodic solutions","","","","","","IMPRS; International Max Planck Research School for Advanced Methods in Process and Systems Engineering","This work is part of the author’s PhD thesis prepared at the Max Planck Institute for Mathematics in the Sciences (MPIMiS) and submitted in June 2009 at the University of Leipzig, Germany. The author would like to thank his supervisor Stefan Müller for the opportunity to work at MPIMiS and for having chosen an interesting problem to work on. Financial support from the International Max Planck Research School ‘Mathematics in the Sciences’ (IMPRS) is also acknowledged.","Hubert A., Schafer R., Magnetic Domains, (1998); Brown W., Micromagnetics, (1963); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); DeSimone A., Kohn R.V., Muller S., Otto F., Recent analytical developments in micromagnetics, Science of Hysteresis, (2005); Guo B., Ding S., Landau-Lifshitz equations, Frontiers of Research with the Chinese Academy of Sciences, vol. 1, (2008); Hardt R., Kinderlehrer D., Some regularity results in ferromagnetism, Comm. Partial Differential Equations, 25, pp. 1235-1258, (2000); Carbou G., Regularity for critical points of a nonlocal energy, Calc. Var. Partial Differential Equations, 5, pp. 409-433, (1997); De Simone A., Hysteresis and imperfection sensitivity in small ferromagnetic particles, Meccanica, 30, pp. 591-603, (1995); Stoner E., Wohlfarth E., A mechanism of magnetic hysteresis in heterogeneous alloys, Phil. Trans. Roy. Soc. London A, 240, pp. 599-642, (1948); Huber A., Boundary regularity for minimizers of the micromagnetic energy functional; Huber A., (2009); Huber A., Time-periodic Néel wall motions; Lunardi A., Analytic Semigroups and Optimal Regularity in Parabolic Problems, Progress in Nonlinear Differential Equations and Their Applications, 16, (1995); Amann H., Dynamic theory of quasilinear parabolic equations. II. Reaction-diffusion systems, Differential Integral Equations, 3, pp. 13-75, (1990); Carbou G., Fabrie P., Regular solutions for Landau-Lifschitz equation in a bounded domain, Differential Integral Equations, 14, pp. 213-229, (2001); Amann H., Ordinary differential equations, de Gruyter Studies in Mathematics, 13, (1990); Abraham R., Marsden J.E., Ratiu T., Manifolds, Tensor Analysis, and Applications, Applied Mathematical Sciences, 75, (1988); Kato T., Perturbation Theory for Linear Operators, Classics in Mathematics, (1995)","A. Huber; NWF I-Mathematik, Universität Regensburg, 93040 Regensburg, Germany; email: alexander2.huber@mathematik.uni-regensburg.de","","","","","","","","10902732","","JDEQA","","English","J. Differ. Equ.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-78651516132" +"Mironov V.L.; Gribkov B.A.; Vdovichev S.N.; Gusev S.A.; Fraerman A.A.; Ermolaeva O.L.; Shubin A.B.; Alexeev A.M.; Zhdan P.A.; Binns C.","Mironov, V.L. (56187729500); Gribkov, B.A. (6507222037); Vdovichev, S.N. (8916243100); Gusev, S.A. (35496664900); Fraerman, A.A. (7003552075); Ermolaeva, O.L. (25925830000); Shubin, A.B. (24921663500); Alexeev, A.M. (55286055800); Zhdan, P.A. (57191357092); Binns, C. (7006499423)","56187729500; 6507222037; 8916243100; 35496664900; 7003552075; 25925830000; 24921663500; 55286055800; 57191357092; 7006499423","Magnetic force microscope tip-induced remagnetization of CoPt nanodisks with perpendicular anisotropy","2009","Journal of Applied Physics","106","5","053911","","","","27","10.1063/1.3202354","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-70349318574&doi=10.1063%2f1.3202354&partnerID=40&md5=a498f80148977963293da48659b5ab82","Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Nanotechnology MDT Company, Zelenograd 124482, Russian Federation; School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, United Kingdom","Mironov V.L., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Gribkov B.A., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Vdovichev S.N., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Gusev S.A., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Fraerman A.A., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Ermolaeva O.L., Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; Shubin A.B., Nanotechnology MDT Company, Zelenograd 124482, Russian Federation; Alexeev A.M., Nanotechnology MDT Company, Zelenograd 124482, Russian Federation; Zhdan P.A., School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Binns C., Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, United Kingdom","We report on the results of a magnetic force microscopy investigation of remagnetization processes in arrays of CoPt nanodisks with diameters of 35 and 200 nm and a thickness of 9.8 nm fabricated by e-beam lithography and ion etching. The controllable magnetization reversal of individual CoPt nanodisks by the magnetic force microscope (MFM) tip-induced magnetic field was demonstrated. We observed experimentally two essentially different processes of tip-induced remagnetization. Magnetization reversal of 200 nm disks was observed when the probe moved across the particle while in case of 35 nm nanodisks one-touch remagnetization was realized. Micromagnetic modeling based on the Landau-Lifshitz-Gilbert (LLG) equation demonstrated that the tip-induced magnetization reversal occurs through the essentially inhomogeneous states. Computer simulations confirmed that in case of 200 nm disks the mechanism of embryo nucleation with reversed magnetization and further dynamic propagation following the probe moving across the particle was realized. On the other hand one-touch remagnetization of 35 nm disks occurs through the inhomogeneous vortexlike state. Micromagnetic LLG simulations showed that magnetization reversal in an inhomogeneous MFM probe field has a lower energy barrier in comparison with the mechanism of coherent rotation, which takes place in a homogeneous external magnetic field. © 2009 American Institute of Physics.","","Computer simulation; Crack propagation; Disks (machine components); Disks (structural components); Magnetic fields; Magnetic force microscopy; Magnetic properties; Magnetic recording; Magnets; Probes; Rare earth alloys; Coherent rotation; Different process; Dynamic propagation; e-Beam lithography; External magnetic field; Ion etching; Landau-Lifshitz-Gilbert equations; Lower energy barriers; Magnetic force microscopes; Micromagnetic modeling; Micromagnetics; Nanodisks; Perpendicular anisotropy; Probe field; Remagnetization; Tip-induced; Magnetization reversal","","","","","","","Chappert C., Bernas H., Ferre J., Kottler V., Jamet J.-P., Chen Y., Cambril E., Devolder T., Rousseaux F., Mathet V., Launois H., Planar patterned magnetic media obtained by ion irradiation, Science, 280, 5371, pp. 1919-1922, (1998); Albrecht M., Moser A., Rettner C.T., Anders S., Thomson T., Terris B.D., Writing of high-density patterned perpendicular media with a conventional longitudinal recording head, Applied Physics Letters, 80, 18, pp. 3409-3411, (2002); Martin J.I., Nogues J., Liu K., Vicent J.L., Schuller I.K., J. Magn. Magn. Mater., 256, (2003); Kryder M.H., Gustafson R.W., High-density perpendicular recording - Advances, issues, and extensibility, Journal of Magnetism and Magnetic Materials, 287, SPEC. ISS., pp. 449-458, (2005); Richter H.J., Dobin A.Y., Heinonen O., Gao K.Z., Veerdonk R.J.M.D., Lynch R.T., Xue J., Weller D., Asselin P., Erden M.F., Brockie R.M., IEEE Trans. Magn., 42, (2006); Moser A., Hellwig O., Kercher D., Dobisz E., Off-track margin in bit patterned media, Applied Physics Letters, 91, 16, (2007); Albrecht M., Rettner C.T., Moser A., Best M.E., Terris B.D., Recording performance of high-density patterned perpendicular magnetic media, Applied Physics Letters, 81, 15, (2002); Albrecht M., Anders S., Thomson T., Rettner C.T., Best M.E., Moser A., Terris B.D., Thermal stability and recording properties of sub-100 nm patterned CoCrPt perpendicular media, Journal of Applied Physics, 91, 10, (2002); Mitsuzuka K., Shimatsu T., Muraoka H., Aoi H., Kikuchi N., Kitakami O., Magnetic properties of Co-Pt/Co hard/soft stacked dot arrays, Journal of Applied Physics, 103, 7, (2008); Chunsheng E., Parekh V., Ruchhoeft P., Khizroev S., Litvinov D., J. Appl. Phys., 103, (2008); Repain V., Jamet J.-P., Vernier N., Bauer M., Ferr J., Chappert C., Gierak J., Mailly D., J. Appl. Phys., 95, (2004); Rastei M.V., Meckenstock R., Bucher J.P., Appl. Phys. Lett., 87, (2005); Jang H.-J., Eames P., Dahlberg E.D., Farhoud M., Ross C.A., Magnetostatic interactions of single-domain nanopillars in quasistatic magnetization states, Applied Physics Letters, 86, 2, pp. 0231021-0231023, (2005); Gider S., Shi J., Awschalom D.D., Hopkins P.F., Campman K.L., Gossard A.C., Kent A.D., Von Molnar S., Appl. Phys. Lett., 69, (1996); Lohau J., Carl A., Kirsch S., Wassermann E.F., Appl. Phys. Lett., 78, (2001); Takahoshi H., Saito H., Ishio S., MFM analysis of magnetization process in CoPt dot-array, Journal of Magnetism and Magnetic Materials, 272-276, SUPPL. 1, (2004); Kleiber M., Kummerlen F., Lohndorf M., Wadas A., Weiss D., Wiesendanger R., Phys. Rev. B, 58, (1998); Zhu X., Grutter P., Metlushko V., Ilic B., Phys. Rev. B, 66, (2002); Zhu X., Grutter P., Metlushko V., Ilic B., Systematic study of magnetic tip induced magnetization reversal of e-beam patterned permalloy particles, Journal of Applied Physics, 91, 10, (2002); Chang J., Mironov V.L., Gribkov B.A., Fraerman A.A., Gusev S.A., Vdovichev S.N., Magnetic state control of ferromagnetic nanodots by magnetic force microscopy probe, Journal of Applied Physics, 100, 10, (2006); Mironov V.L., Gribkov B.A., Fraerman A.A., Gusev S.A., Vdovichev S.N., Karetnikova I.R., Nefedov I.M., Shereshevsky I.A., MFM probe control of magnetic vortex chirality in elliptical Co nanoparticles, Journal of Magnetism and Magnetic Materials, 312, 1, pp. 153-157, (2007); Chang J., Yi H., Cheol Koo H., Mironov V.L., Gribkov B.A., Fraerman A.A., Gusev S.A., Vdovichev S.N., Magnetization reversal of ferromagnetic nanoparticles under inhomogeneous magnetic field, Journal of Magnetism and Magnetic Materials, 309, 2, pp. 272-277, (2007); Shen J.X., Kirby R.D., Wierman K., Shan Z.S., Sellmyer D.J., Suzuki T., J. Appl. Phys., 73, (1993); Aktag A., Michalski S., Yue L., Kirby R.D., Liou S.-H., Formation of an anisotropy lattice in Co/Pt multilayers by direct laser interference patterning, Journal of Applied Physics, 99, 9, (2006); Fraerman A.A., Gusev S.A., Mazo L.A., Nefedov I.M., Nozdrin Yu.N., Karetnikova I.R., Sapozhnikov M.V., Shereshevsky I.A., Sukchodoev L.V., Phys. Rev. B, 65, (2002); Boerner E.D., Bertran H.N., IEEE Trans. Magn., 33, (1997); Varvaro G., Agostinelli E., Laureti S., Testa A.M., Garcia-Martin J.M., Briones F., Fiorani D., J. Phys. D, 41, (2008); Yu M., Liu Y., Sellmyer D.J., J. Appl. Phys., 87, (2000); Liou S.H., Huang S., Klimek E., Kirby R.D., Yao Y.D., J. Appl. Phys., 85, (1999); Gapin A.I., Ye X.R., Aubuchon J.F., Chen L.H., Tang Y.J., Jin S., CoPt patterned media in anodized aluminum oxide templates, Journal of Applied Physics, 99, 8, (2006); Goldstein J., Newbury D., Echlin P., Joy D., Fiori C., Lifshin E., Scanning Electron Microscopy and X-ray Microanalysis, (1981); Stoner E.C., Wohlfarth E.P., Philos. Trans. R. Soc. Lond. A, 240, (1948); Okamoto S., Kato T., Kikuchi N., Kitakami O., Tezuka N., Sugimoto S., Energy barrier and reversal mechanism in Co/Pt multilayer nanodot, Journal of Applied Physics, 103, 7, (2008); Hu G., Thomson T., Rettner C.T., Raoux S., Terris B.D., Magnetization reversal in CoPd nanostructures and films, Journal of Applied Physics, 97, 10, pp. 1-3, (2005); Kikuchi N., Okamoto S., Kitakami O., Shimada Y., Fukamichi K., Appl. Phys. Lett., 82, (2003); Mitsuzuka K., Kikuchi N., Shimatsu T., Kitakami O., Aoi H., Muraoka H., Lodder J.C., Switching field and thermal stability of CoPt/Ru dot arrays with various thicknesses, IEEE Transactions on Magnetics, 43, 6, pp. 2160-2162, (2007); Moutafis C., Komineas S., Vaz C.A.F., Bland J.A.C., Shima T., Seki T., Takanashi K., Phys. Rev. B, 76, (2007)","V. L. Mironov; Institute for Physics of Microstructures, RAS, Nizhniy Novgorod 603950, Russian Federation; email: mironov@ipm.sci-nnov.ru","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-70349318574" +"Ho P.; Evans R.F.L.; Chantrell R.W.; Han G.; Chow G.-M.; Chen J.","Ho, Pin (37099755900); Evans, Richard F. L. (13607717600); Chantrell, Roy W. (7102157314); Han, Guchang (7202923478); Chow, Gan-Moog (7006494644); Chen, Jingsheng (57203098024)","37099755900; 13607717600; 7102157314; 7202923478; 7006494644; 57203098024","Atomistic modeling of the interlayer coupling behavior in perpendicularly magnetized L10-FePt/Ag/L10-FePt pseudo spin valves","2011","IEEE Transactions on Magnetics","47","10","6027571","2646","2648","2","4","10.1109/TMAG.2011.2147765","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80053490251&doi=10.1109%2fTMAG.2011.2147765&partnerID=40&md5=9e404531ae5db8e3b8c90f0ed8e5ad84","Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore, Singapore; ASTAR Data Storage Institute, 117608 Singapore, Singapore; Department of Physics, University of York, YO10 5DD York, United Kingdom","Ho P., Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore, Singapore, ASTAR Data Storage Institute, 117608 Singapore, Singapore; Evans R.F.L., Department of Physics, University of York, YO10 5DD York, United Kingdom; Chantrell R.W., Department of Physics, University of York, YO10 5DD York, United Kingdom; Han G., ASTAR Data Storage Institute, 117608 Singapore, Singapore; Chow G.-M., Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore, Singapore; Chen J., Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore, Singapore","An atomistic model based on a classical spin Hamiltonian and a Landau-Lifshitz-Gilbert (LLG) equation was utilized to simulate and gain understanding of the magnetic, interfacial, and reversal properties of perpendicular anisotropy L10-FePt/Ag/L10-FePt pseudo spin valves, with different interfacial roughness, representing the experimentally observed behavior of the interface where the Ag spacer layer was postannealed at different temperatures. Simulation results showed that the influence of the Ag spacer on the independent switching of the FePt layers became stronger with a greater degree of interlayer mixing under higher temperature treatment. This was the result of an increased magnetic polarization of Ag with a decrease in Ag spacer thickness. Furthermore, with greater intermixing the magnetization reversal of the harder fixed FePt layer also changed from a coherent reversal process to one which took place via nucleation and propagation of reversed domains. © 2011 IEEE.","Ag; atomistic model; FePt; intermixing; pseudo spin valves","Binary alloys; Magnetic devices; Magnetization reversal; Magnetoresistance; Platinum alloys; Shims; Silver; Atomistic modeling; Classical spin Hamiltonians; FePt; intermixing; Landau-Lifshitz-Gilbert equations; Magnetic polarizations; Perpendicular anisotropy; Pseudo spin valves; Iron alloys","","","","","Agency for Science, Technology and Research, A*STAR; Ministry of Education - Singapore, MOE, (T11-1001-P04); Science and Engineering Research Council, SERC, (092-156-0118)","ACKNOWLEDGMENT This work was supported in part by Agency of Science, Technology and Research (A*STAR), Singapore, SERC Grant 092-156-0118, and Ministry of Education, Singapore, Tier 1 Funding T11-1001-P04.","Zhu J.G., Magnetoresistive random access memory: The path to competitiveness and scalability, IEEE. Trans. Magn., 96, pp. 1786-1798, (2008); Slaughter J.M., Materials for magnetoresistive random access memory, Annu. Rev. Mater. Res., 39, pp. 277-296, (2009); Carapella F.RussoG., Granata V., Martucciello N., Costabile G., Pseudo spin-valves with Al or Nb as spacer layer: GMR and search for spin switch behavior, Eur. Phys. J. B., 60, pp. 61-66, (2007); Tehrani S., Durlam M., DeHerrera M., Chen E., High density pseudo spin valve magnetoresistive RAM, Proc. Int. NonVolatile Memory Technol. Conf., pp. 43-46, (1998); Paul A., Damm T., Burgler D.E., Stein S., Kohlstedt H., Grunberg P., Optimizing the giant magnetoresistance of NiFe/Cu/Co pseudo spin-valves prepared by magnetron sputtering, Appl. Phys. Lett., 82, pp. 1905-1907, (2003); Ho P., Han G.C., R.W. Chantrell, Evans R.F.L., Chow G.M., Chen J.S., Perpendicular anisotropy-FePt based pseudo spin valve with Ag spacer layer, Appl. Phys. Lett., 98, (2011); Ho E.M., Petford-Long A.K., Cerezo A., The effect of interfacial regions on the giantmagnetoresistance in as-grown and annealed Fe/Cr MLFs, J. Magn. Magn. Mater., 192, pp. 431-442, (1999); Rodriguez G.J.B., Pereira L.G., Miranda M.G.M., Antunes A.B., Baibich M.N., Magnetotransport and coupling in nanostructured Co/Ag thin films, J. Magn. Magn. Mater., 214, pp. 78-84, (2000); Laidler H., Hickey B.J., Hase T.P.A., Tanner B.K., Schad R., Bruynseraede Y., Effect of annealing on the roughness andGMRof Fe/Cr multilayers, J. Magn.Magn. Mater., 156, pp. 332-334, (1996); Thongmee S., Liu B.H., Ding J., Yi J.B., Diffusion induced columnar structure, high perpendicular anisotropy and low transformation temperature in thick FePt films, Thin Solid Films, 518, pp. 7053-7058, (2010); Chen S.C., Kuo P.C., Sun A.C., Chou C.Y., Fang Y.H., Kuo S.Y., Microstructure and coercivity of granular nanocomposite FePt-Ag multilayer films, IEEE Trans. Magn., 41, pp. 3340-3342, (2005)","J. Chen; Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore, Singapore; email: msecj@nus.edu.sg","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-80053490251" +"Smith R.K.; Grabowski M.; Camley R.E.","Smith, Ryan K. (28867514100); Grabowski, Marek (22961179300); Camley, R.E. (7005900299)","28867514100; 22961179300; 7005900299","Period doubling toward chaos in a driven magnetic macrospin","2010","Journal of Magnetism and Magnetic Materials","322","15","","2127","2134","7","23","10.1016/j.jmmm.2010.01.045","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77952102998&doi=10.1016%2fj.jmmm.2010.01.045&partnerID=40&md5=582c97549eb1de76eed81e6afebc7049","Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, United States","Smith R.K., Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, United States; Grabowski M., Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, United States; Camley R.E., Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, United States","The Landau-Lifshitz-Gilbert equation is analyzed in the case of a configuration involving easy plane isotropy under the influence of a sinusoidally oscillating magnetic field and a demagnetizing field. Through the use of numerical techniques, chaotic behavior is found and analyzed. By reducing the system to a discrete map (numerically), bifurcation diagrams for the system are computed. The system is found to exhibit a period doubling cascade route to chaos, and it obeys certain convergence rules for chaotic transitions outlined by Feigenbaum. A connection is drawn between the route to chaos and the geometry of the system, and comparisons are made with similar systems. Within the chaotic regime, windows of arbitrarily large period are suspected to exist, and explicitly illustrated and discussed for a period three window. © 2010 Elsevier B.V. All rights reserved.","Demagnetizing field; LLG; Magnetic bifurcation diagrams; Magnetic chaos; Magnetic nonlinearity; Magnetic period doublings","Bifurcation (mathematics); Magnetic fields; Magnetic materials; Spot welding; Bifurcation diagram; Chaotic behaviors; Demagnetizing field; Doublings; Easy plane; Landau-Lifshitz-Gilbert equations; Magnetic non-linearity; Numerical techniques; Oscillating magnetic fields; Period doubling; Period doubling cascade; Chaotic systems","","","","","State of Connecticut Department of Agriculture, DOA, (W911NF-04-1-0247)","This work was supported by DOA Grant no. W911NF-04-1-0247 . The bifurcation diagrams herein were produced through parallel computation using Mathematica with Wolfram Research, Inc. usage licenses.","Walker L.R., Magnetism, (1963); Back C.H., Allenspach R., Weber W., Parkin S.S.P., Weller D., Garwin E.L., Siegmann H.C., Science, 285, (1999); Bertotti G., Serpico C., Mayergoyz I.D., Magni A., d'Aquino M., Bonin R., Phys. Rev. Lett., 94, (2005); Florez S.H., Katine J.A., Carey M., Folks L., Terris B.D., J. Appl. Phys., 103, (2008); Alvarez L.F., Pla O., Chubykalo O., Phys. Rev. B., 61, (2000); Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Zhang X.Y., Suhl H., Phys. Rev. B., 38, (1988); Carroll T.L., Pecora L.M., Rachford F.J., Phys. Rev A., 40, (1989); Carroll T.L., Rachford F.J., Pecora L.M., Phys. Rev. B., 38, (1988); Peterman D.W., Ye M., Wigen P.E., Phys. Rev. Lett., 74, (1995); Rezende S.M., de Alcantara Bonfim O.F., de Aguiar F.M., Phys. Rev. B., 33, (1986); de Aguiar F.M., da Silva F.C.S., Rezende S.M., Phys. Rev. E., 52, (1995); Dimian M., Mayergoyz I.D., Bertotti G., Serpico C., J. Appl. Phys., 99, (2006); Chester W., J. Inst. Math. Appl., 15, pp. 289-306, (1975); Strogatz S.H., Nonlinear Dynamics and Chaos, (1994); Feigenbaum M.J., J. Stat. Phys., 19, (1978); Feigenbaum M.J., Los Alamos Science, 1, (1980); Hilborn R.C., Chaos and Nonlinear Dynamics, (2000); May R.M., Nature, 261, (1976); Ott E., Chaos in Dynamical Systems, (2002); York J.A., Grebogi C., Ott E., Tedeschini-Lalli L., Phys. Rev. Lett., 54, (1985); Camley R.E., Celinski Z., Fal T., Glushchenko A.V., Hutchison A.J., Khivintsev Y., Kuanr B., Harward I.R., Veerakumar V., Zagarodnii V.V., J. Magn. Magn. Mater., 321, (2009)","R.K. Smith; Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, CO 80933-7150, United States; email: rykeelty@gmail.com","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-77952102998" +"Cimpoesu D.; Spinu L.; Stancu A.","Cimpoesu, Dorin (6507485811); Spinu, Leonard (9732365200); Stancu, Alexandru (14037953900)","6507485811; 9732365200; 14037953900","Transverse susceptibility method in nanoparticulate magnetic media","2008","Journal of Nanoscience and Nanotechnology","8","6","","2731","2744","13","5","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-48949096878&partnerID=40&md5=c6eb480270d34505de369e6a35da044a","Advanced Materials Research Institute, University of New Orleans, LA 70148, United States; Alexandru Ioan Cuza University, Department of Physics, Centre for Applied Research in Physics and Advanced Technologies, Iasi, 700506, Blvd. Carol I, 11, Romania; AMRI, Department of Physics, University of New Orleans, LA 70148, United States","Cimpoesu D., Advanced Materials Research Institute, University of New Orleans, LA 70148, United States, Alexandru Ioan Cuza University, Department of Physics, Centre for Applied Research in Physics and Advanced Technologies, Iasi, 700506, Blvd. Carol I, 11, Romania; Spinu L., AMRI, Department of Physics, University of New Orleans, LA 70148, United States; Stancu A., Alexandru Ioan Cuza University, Department of Physics, Centre for Applied Research in Physics and Advanced Technologies, Iasi, 700506, Blvd. Carol I, 11, Romania","Transverse susceptibility (TS) method is a reliable method for the determination of anisotropy in nanoparticulate media. To correctly evaluate the value of anisotropy in various modern nanostructured materials, a number of theoretical problems related to the method have to be well understood to avoid significant systematic errors. This paper presents the state of the art in the TS method which includes the expression for single domain particles with any type of anisotropy, the theoretical and micromagnetic, using Landau-Lifshitz-Gilbert (LLG) equation and stochastic LLG equation studies of the effects of ac field amplitude, inter-particle interactions, and magnetic relaxation. The problem of both real and imaginary parts of the TS signal is also discussed. Copyright © 2008 American Scientific Publishers All rights reserved.","FMR; Stoner-Wohlfarth model; Transverse susceptibility","Anisotropy; Ferromagnetic resonance; Magnetic susceptibility; Stochastic systems; Systematic errors; Inter-particle interaction; Landau-Lifshitz-Gilbert equations; Nano particulates; Real and imaginary; Single domain particles; State of the art; Stoner-Wohlfarth model; Transverse susceptibility; Magnetic field effects","","","","","","","Aharoni A., Frei E.H., Shtrikman S., Treves D., Bull. Res. Counc. Israel, 6 A, (1957); Hoare A., Chantrell R.W., Schmitt W., Eilling A., J. Phys. D, 26, (1993); Cullity B.D., Introduction to Magnetic Materials, 213, (1972); Spinu L., Stancu A., O'Connor C.J., Phys. B, 306, (2001); Spinu L., Stancu A., O'Connor C.J., Appl. Phys. Lett, 80, (2002); Thiaville A., J. Magn. Magn. Mater, 182, (1998); Chang C.R., J. Appl. Phys, 69, (1991); Spinu L., O'Connor C.J., Srikanth H., IEEE Trans. Magn, 37, (2001); Spinu L., Srikanth H., Gupta A., Li X.W., Xiao G., Phys. Rev. B, 62, (2000); Russek S.E., Kabos P., Silva T., Mancoff F.B., Wang D., Qian Z., Daughton J.M., IEEE Trans. Magn, 37, (2001); Atkinson D., Squire P.T., J. Appl. Phys, 83, (1998); Spinu L., Dumitru I., Stancu A., Cimpoesu D., J. Magn. Magn. Mater, 296, (2006); Dumitru I., Stancu A., Cimpoesu D., Spinu L., J. Appl. Phys, (2005); Skrotskii G.V., Kurbatov L.V., Sov. Phys. JETP, 35, (1959); Ferromagnetic Resonance, (1966); Gilbert T.L., Phys. Rev, 100, (1955); Spinu L., Pham H., Radu C., Denradin J.C., Dumitru I., Knobel M., Dorneles L.S., Schelp L.F., Stancu A., Appl. Phys. Lett, 86, (2005); Papusoi Jr. C., Phys. Lett. A, 265, (2000); Richter H.J., IEEE Trans. Magn, 26, (1990); Chang C.R., Yang J.S., Appl. Phys. Lett, 65, (1994); Yang J.S., Lee J., Klik I., Chang C.R., J. Magn. Magn. Mater, 140, (1995); Klik I., Chang C.R., IEEE Trans. Magn, 31, (1995); Chang C.R., Yang J.S., IEEE Trans. Magn, 30, (1994); Cimpoesu D., Postolache P., Stancu A., J. Appl. Phys, 93, (2003); Stancu A., Spinu L., O'Connor C.J., J. Magn. Magn. Mater, 242, (2002); Spinu L., Cimpoesu D., Stoleriu L., Stancu A., IEEE Trans. Magn, 39, (2003); Ross C.A., Smith H.I., Savas T., Schattenburg M., Farhoud M., Hwang M., Walsh M., Abraham M.C., Ram R.J., J. Vac. Sci. Technol. B, 17, (1999); O'Handley R.C., Modern Magnetic Materials-Principles and Applications, 192, (2000); Stancu A., Spinu L., J. Magn. Magn. Mater, 266, (2003); Thiaville A., Phys. Rev. B, 61, (2000); Cimpoesu D., Stancu A., Dumitru I., Spinu L., IEEE Trans. Magn, 41, (2005); Chantrell R.W., Hoare A., Melville D., Lutke-Stetzkamp H.J., Methfessel S., IEEE Trans. Magn, 25, (1989); Cimpoesu D., Stancu A., Spinu L., Phys. Rev. B, 76, (2007); Lee J., Klik I., Chang C.R., J. Magn. Magn. Mater, 129, (1994); Klik I., Yao Y.D., J. Magn. Magn. Mater, 186, (1998); Lu J.J., Huang H.L., Chang C.R., Klik I., J. Appl. Phys, 75, (1994); Yang J.S., Chang C.R., Klik I., Phys. Rev. B, 51, (1995); Gittleman J.I., Abebes B., Bozowski S., Phys. Rev. B, 9, (1974); Ju G., Chantrell R., Zhou H., Weller D., Lu B., Dig. INTERMAG, (2003); Ju G., Chantrell R., Zhou H., Weller D., Complex Transverse ac Magneto-Optic Susceptometer for Determination of Volume and Anisotropy Field Distribution in Recording Media,; Ju G.P., Zhou H., Chantrell R., Lu B., Weller D., J. Appl. Phys, 99, (2006); Yuan E., Victora R.H., IEEE Trans. Magn, 40, (2004); Brown Jr. W.F., Phys. Rev, 130, (1963); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Garcia-Palacios J.L., Adv. Chem. Phys, 112, (2000); Kloeden P.E., Platen E., Numerical Solution of Stochastic Differential Equations, (1995); Aharoni A., Phys. Rev, 135, (1964); Cimpoesu D., Stancu A., Spinu L., J. Appl. Phys, (2006); Cimpoesu D., Stancu A., Spinu L., IEEE Trans. Magn, 42, (2006); Cimpoesu D., Spinu L., Stancu A., J. Appl. Phys, (2005); Cimpoesu D., Stancu A., Spinu L., J. Appl. Phys, (2006); Cimpoesu D., Stancu A., Spinu L., IEEE Trans. Magn, 42, (2006); Tanasa R., Enachescu C., Stancu A., Linares J., Varret F., J. Appl. Phys, 95, (2004); Tanasa R., Enachescu C., Stancu A., Linares J., Varret F., Physica B, 343, (2004)","","","American Scientific Publishers","","","","","","15334880","","JNNOA","","English","J. Nanosci. Nanotechnol.","Review","Final","","Scopus","2-s2.0-48949096878" +"Wang X.; Gao K.; Seigler M.","Wang, Xiaobin (55736904000); Gao, Kaizhong (7101642130); Seigler, Mike (6602676771)","55736904000; 7101642130; 6602676771","Magnetization dynamics coarse graining through Landau-Lifshitz-Gilbert equation renormalization","2011","IEEE Transactions on Magnetics","47","10","6028186","2676","2679","3","3","10.1109/TMAG.2011.2146235","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80053466539&doi=10.1109%2fTMAG.2011.2146235&partnerID=40&md5=c9afbeb8fddf58e8089e82fbcbaf82f9","Seagate Technology, Bloomington, MN 55435, United States","Wang X., Seagate Technology, Bloomington, MN 55435, United States; Gao K., Seagate Technology, Bloomington, MN 55435, United States; Seigler M., Seagate Technology, Bloomington, MN 55435, United States","Coarse-graining ferromagnetic dynamics is obtained from fine-graining magnetization dynamics through Landau-Lifshitz-Gilbert (LLG) equation renormalization. Analytical formulas are obtained to connect LLG dynamics at separate spatial and temperature scales by averaging out fast spatial-varying magnetization components. Besides rescaling transverse LLG damping, a longitudinal damping term appears in the renormalization process, which increases with temperature. © 2011 IEEE.","Coarse graining; Landau-Lifshitz-Gilbert (LLG) renormalization; magnetization dynamics","Damping; Magnetization; Temperature scales; Analytical formulas; Coarse Graining; Damping terms; Landau-Lifshitz-Gilbert equations; Magnetization components; Magnetization dynamics; Renormalization; Rescaling; Dynamics","","","","","","","Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, (1956); Gilbert T.L., Phys. Rev., 100, (1955); Brown W.F., Phys. Rev., 130, (1963); Feng X., Visscher P.B., J. Appl. Phys., 89, (2001); Grinstein G., Koch R.H., Phys. Rev. Lett., 90, (2003); Garan D.A., Phys. Rev. B, 55, (1997); Kazantseva N., Hinzke D., Nowak U., Chantrell R.W., Atxitia U., Chubykalo-Fesenko O., Phys. Rev. B, 77, (2008); Brezin E., Zinn-Just J., Phys. Rev. Lett., 36, (1976); Nelson D.R., Pelcovis R.A., Phys. Rev. B, 16, (1977)","X. Wang; Seagate Technology, Bloomington, MN 55435, United States; email: xiaobin.wang@seagate.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-80053466539" +"Ciubotaru F.; Stancu A.; Cerchez M.","Ciubotaru, F. (9734943500); Stancu, A. (14037953900); Cerchez, M. (57188744858)","9734943500; 14037953900; 57188744858","Micromagnetic simulations of fast switching in single-domain ferromagnetic particles","2006","Journal of Optoelectronics and Advanced Materials","8","5","","1744","1747","3","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33750596290&partnerID=40&md5=2cca56843fa754c001b61eb1af343c4f","Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania; Heinrich-Heine-Universität, 40225 Düsseldorf, Universitätsstr. 1, Germany","Ciubotaru F., Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania; Stancu A., Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania; Cerchez M., Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania, Heinrich-Heine-Universität, 40225 Düsseldorf, Universitätsstr. 1, Germany","In this paper we present the results of numerical simulations concerning the thermal effects in the dynamics and the switching probability of one spin magnetic particle with a thin-film like geometry and in-plane anisotropy. The dynamics of magnetization vector is calculated using the LLG equation and Langevin formalism. We have determined the maximum angle of dispersion due to thermal fluctuation as a function of temperature and we calculate the time window when switching has probability 1 and study this as a function of the applied field.","Magnetization switching; Single domain particle; Stochastic landau-lifshitz-gilbert equation","Magnetization; Spin dynamics; Stochastic systems; Ferromagnetic particles; Landau-Lifshitz-Gilbert equations; Magnetization switching; Magnetization vector; Micromagnetic simulations; Single domain particles; Switching probability; Thermal fluctuations; Switching","","","","","","","Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 93, (2003); Bertotti G., Mayergoyz I.D., Serpico C., IEEE Trans. Magn., 39, (2003); Bauer M., Fassbender J., Hillebrands B., Phys. Rev. B, 61, (2000); Beaurepaire E., Merle J.-C., Daunois A., Bigot J.-Y., Phys. Rev. Lett., 76, (1996); Hohlfeld J., Matthias E., Knorren R., Bennemann K.H., Phys. Rev. Lett., 78, (1997); Scholl A., Baumgarten L., Jacquemin R., Eberhardt W., Phys. Rev.Lett., 79, (1997); Berkov D.V., Gorn N.L., Gornert P., Phys. Stat. Sol., 189, (2002); Berkov D.V., Gorn N.L., J. Phys: Condens. Matter., 14, (2002); Ciubotaru F., Stancu A., Stoleriu L., J. Optoelectron. Adv. Mater., 6, (2004)","A. Stancu; Department of Solid State and Theoretical Physics, Alexandru Ioan Cuza University, 700506 Iasi, Romania; email: alstancu@uaic.ro","","National Institute of Optoelectronics","","","","","","14544164","","","","English","J. Optoelectron. Adv. Mat.","Article","Final","","Scopus","2-s2.0-33750596290" +"Kudtarkar S.K.","Kudtarkar, Santosh Kumar (35111441300)","35111441300","Non-equilibrium magnetisation corrected dynamics of textured itinerant magnets","2010","Physica B: Condensed Matter","405","8","","1993","1999","6","0","10.1016/j.physb.2010.01.087","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77949269497&doi=10.1016%2fj.physb.2010.01.087&partnerID=40&md5=7bdcbbaebcd547d5c739f59a1cc51753","Centre for Mathematical Modelling, FLAME, Baner, Pune 411 045, 150/7, Baner-Balewadi Road, India","Kudtarkar S.K., Centre for Mathematical Modelling, FLAME, Baner, Pune 411 045, 150/7, Baner-Balewadi Road, India","We use a temperature dependent drift-diffusion model of magnetisation and charge currents in conjunction with an s-d model to arrive at the expression for the transverse spin accumulation (non-equilibrium magnetisation) in itinerant magnets with textures. Dynamical magnetisation states in textured magnets gives rise to spin pumped currents and results in an induced voltage and the electric field associated with this voltage has to be accounted for. We incorporate this into the Landau-Lifshitz equation for magnetisation dynamics with Gilbert damping (LLG) and obtain a new generalised equation for magnetisation dynamics. In addition, Thiele's equations corresponding to the modified LLG are given. The presence of magnetisation textures introduces an anisotropy into the system. A simple expression of the anisotropic resistivity and Hall current is derived. © 2010 Elsevier B.V. All rights reserved.","Current and temperature driven spin pumping; Landau-lifshitz equation; Spin polarised transport","Anisotropy; Electric fields; Electromagnets; Nonlinear equations; Partial differential equations; Pumps; Spin dynamics; Textures; Anisotropic resistivity; Charge current; Drift-diffusion model; Gilbert damping; Hall current; Induced voltages; Itinerant magnets; Landau Lifshitz equation; Magnetisation; Non equilibrium; Simple expression; Spin polarised transport; Spin-accumulations; Spin-pumping; Temperature dependent; Magnetization","","","","","","","Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater, 159, (1996); Tatara G., Kohno H., Shibata J., Phys. Rep., 468, (2008); Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Duine R.A., Phys. Rev. B, 77, (2008); Barnes S.E., Maekawa S., Phys. Rev. Lett., 98, (2007); Tserkovnyak Y., Mecklenburg M., Phys. Rev. B, 77, (2008); Landau L., Lishitz E., Phys. Z. Sowjet., 8, (1935); Bazaliy Ya.B., Jones B.A., Zhang S.C., Phys. Rev. B, 57, (1998); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Thiaville A., Et al., Europhys. Lett., 69, (2005); Blundell S., Magnetism in Condensed Matter, (2001); Zutic I., Et al., Rev. Modern Phys., 76, (2004); Landau L., Lishitz E., Electrodynamics of Continuous Media, (1984); Callen H.B., Thermodynamics and an Introduction to Thermostatics, (1985); Concepts in Spin Electronics, (2006); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Thiele A.A., Phys. Rev. Lett., 30, (1973); Hubert A., Schafer R., Magnetic Domains, (1998); Kudtarkar S.K., Phys. Lett. A, 374, (2009); Bruno P., Et al., Phys. Rev. Lett., 93, (2004); Shibata J., Et al., Phys. Rev. B, 73, (2006)","S.K. Kudtarkar; Centre for Mathematical Modelling, FLAME, Baner, Pune 411 045, 150/7, Baner-Balewadi Road, India; email: sant.kk@gmail.com","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-77949269497" +"Heinrich B.; Woltersdorf G.","Heinrich, B. (35501028000); Woltersdorf, G. (6601944232)","35501028000; 6601944232","Intrinsic spin relaxation processes in metallic magnetic multilayers","2007","Journal of Superconductivity and Novel Magnetism","20","2 SPECIAL ISSUE","","83","89","6","5","10.1007/s10948-006-0216-1","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33847361435&doi=10.1007%2fs10948-006-0216-1&partnerID=40&md5=766a2272bb817c4408445b388d74b77d","Physics Department, Simon Fraser University, University Drine, Burnaby, BC V5A 1S6, Canada","Heinrich B., Physics Department, Simon Fraser University, University Drine, Burnaby, BC V5A 1S6, Canada; Woltersdorf G., Physics Department, Simon Fraser University, University Drine, Burnaby, BC V5A 1S6, Canada","Spin relaxation processes in metallic magnetic nanostructures are reviewed. First a brief review of the phenomenology of magnetic damping is presented using the Landau Lifshitz Gilbert (LLG) equations of motion. It is shown that the Gilbert damping in bulk metallic layers is caused by the spin orbit interaction and itinerant character of 3d and 4s-p electrons. Spin dynamics in magnetic nanostructures acquires an additional nonlocal damping. This means that a part of the magnetic damping is not given by the local Gilbert damping but arises from the proximity to other layers. Spin pumping and spin sink concepts will be introduced and used to describe the interface nonlocal Gilbert damping in magnetic multilayers. The modified LLG equation of motion in magnetic multilayers will be introduced and tested against the ferromagnetic resonance (FMR) data around the accidental crossover of FMR fields. The spin pumping theory will be compared to the early theories introduced in the 1970s for the interpretation of transmission electron spin resonance (TESR) measurements across ferromagnet/normal metal sandwiches. © Springer Science+Business Media, LLC 2007.","FMR; Gilbert damping; Metallic magnetic nanostructures; Spin pump; Spin relaxation; Spin sink","Equations of motion; Ferromagnetic materials; Ferromagnetic resonance; Interfaces (materials); Magnetic materials; Relaxation processes; Gilbert damping; Landau Lifshitz Gilbert (LLG) equations; Metallic magnetic nanostructures; Spin pump; Spin relaxation; Spin sinks; Transmission electron spin resonance (TESR); Multilayers","","","","","","","MacDonald J.R., Proc. Phys. Soc, 64, (1951); Heinrich B., Magnetic Ultrathin Film Structures II, pp. 195-222, (1994); Heinrich B., Cochran J.F., Adv. Phys, 42, (1993); Heinrich B., Cochran J.F., Kowalewski M., Frontiers in Magnetism of Reduced Dimension Systems, NATO-ASI Series, (1996); Goerlitz D., Koetzler J., Eur. Phys. J. B, 5, (1998); Kambersky V., Czech. J. Phys. B, 26, (1976); Heinrich B., Ultrathin Magnetic Structures III, (2004); Heinrich B., Fraitova D., Kambersky V., Phys. Stat. Sol, 23, (1967); Kambersky V., Czech. J. Phys, 34, (1984); Kunes J., Kambersky V., Phys. Rev. B, 65, (2002); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett, 84, (2000); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Seek M., Tsoi V., Wyder P., Phys. Rev. Lett, 80, (1998); Slonczewski J.C., J. Magn. Magn. Mater, 159, (1996); Kiselev S.I., Sankey J.C., Krivorotov I.N., Empley N.C., Schoelkopf R.J., Burman R.A., Ralph D.C., Nature, 425, (2003); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett, 88, (2002); Brouwer P.W., Phys. Rev. B, 58, (1998); Urban R., Woltersdorf G., Heinrich B., Phys. Rev. Lett, 87, (2001); Heinrich B., Tserkovnyak Y., Woltersdorf G., Brataas A., Urban R., Bauer G., Phys. Rev. Lett, 90, (2003); Enders A., Monchesky T., Myrtle K., Urban R., Heinrich B., Kirschner J., Zhang X.-G., Butler W.H., J. Appl. Phys, 89, (2001); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Heinrich B., Celinski Z., Cochran J.F., Muir W.B., Rudd J., Zhong Q.M., Arrott A.S., Myrtle K., Kirschner J., Phys. Rev. Lett, 64, (1990); Lenz K., Tolinski T., Linder J., Kosubek E., Baberschke K., Phys. Rev. B, 69, (2004); Heinrich B., Woltersdorf G., Urban R., Simanek E., J. Appl. Phys, 93, (2003); Woltersdorf G., Heinrich B., Phys. Rev. B, 69, (2004); Silsbee R.H., Janossy A., Monod P., Phys. Rev. B, 19, (1979); Urban R., Heinrich B., Woltersdorf G., J. Appl. Phys, 93, (2003)","B. Heinrich; Physics Department, Simon Fraser University, University Drine, Burnaby, BC V5A 1S6, Canada; email: bheinric@sfu.ca","","","","","","","","15571947","","","","English","J Supercond Novel Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-33847361435" +"Kanai Y.; Jinbo Y.; Tsukamoto T.; Greaves S.J.; Yoshida K.; Muraoka H.","Kanai, Yasushi (56530175700); Jinbo, Yoshihiro (36716327300); Tsukamoto, Toshio (14320866500); Greaves, Simon John (7006831295); Yoshida, Kazuetsu (23017498800); Muraoka, Hiroaki (12756598400)","56530175700; 36716327300; 14320866500; 7006831295; 23017498800; 12756598400","Finite-element and micromagnetic modeling of Write heads for shingled recording","2010","IEEE Transactions on Magnetics","46","3 PART 1","","715","721","6","50","10.1109/TMAG.2009.2038354","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79961231976&doi=10.1109%2fTMAG.2009.2038354&partnerID=40&md5=0879b6890c376b868cc4bf911e5c56f9","Niigata Institute of Technology, Kashiwazaki, Niigata 945-1195, Japan; Tohoku University, Sendai, Miyagi 980-8577, Japan; Kogakuin University, Shinjuku-ku, Tokyo 163-8677, Japan","Kanai Y., Niigata Institute of Technology, Kashiwazaki, Niigata 945-1195, Japan; Jinbo Y., Niigata Institute of Technology, Kashiwazaki, Niigata 945-1195, Japan; Tsukamoto T., Niigata Institute of Technology, Kashiwazaki, Niigata 945-1195, Japan; Greaves S.J., Tohoku University, Sendai, Miyagi 980-8577, Japan; Yoshida K., Kogakuin University, Shinjuku-ku, Tokyo 163-8677, Japan; Muraoka H., Tohoku University, Sendai, Miyagi 980-8577, Japan","Finite element method (FEM) modeling was used in conjunction with micromagnetic media simulations to investigate new write heads for shingled recording targeting 2 terabit per square inch (Tbit\in2 and above on conventional continuous media. In order to obtain higher recording densities, an asymmetric main pole yoke, corner shields, and an ultimate MR read head were investigated. The validity of a FEM model solving Maxwell's equations (Maxwell FEM) was investigated and compared with a Landau-Lifshitz-Gilbert (LLG) micromagnetic model. It was found that the magnetostatic recording field obtained by Maxwell FEM and the quasi-static field obtained by micromagnetic calculation were in good agreement provided the micromagnetic mesh quality was good. It was also found that the dynamic recording field closely followed a driving current of up to 1.0 GHz. Finally, the required medium signal-to-noise ratio (SNR) was considered. © 2010 IEEE.","Index Terms-Micromagnetic simulations; Perpendicular magnetic recording; Recording write heads; Shingled recording scheme","Finite element method; Magnetic heads; Maxwell equations; Finite element method model (FEM); Landau-Lifshitz-Gilbert; Micromagnetic calculations; Micromagnetic modeling; Micromagnetic simulations; Perpendicular magnetic recording; Recording write heads; Shingled recordings; Signal to noise ratio","","","","","HGST; Semiconductor Research Corporation, SRC; Japan Society for the Promotion of Science, JSPS, (18 560 352, 21560374); Ministry of Education, Culture, Sports, Science and Technology, MEXT","Funding text 1: The authors acknowledge the support from the members of the Storage Research Consortium (SRC), Japan, especially from Dr. I. Tagawa, HGST. The authors also would like to acknowledge the use of JMAG-Studio, FEM Software, from JSOL, Ltd. Dr. Werner Scholz, Seagate Research, supported the use of MAGPAR, public domain micromagnetic software.; Funding text 2: This work was supported in part by a Grant in Aid from the Japan Society for the Promotion of Science (#18 560 352 and 21 560 374), by the Research and Development for Next-Generation Information Technology project of the MEXT, Japanese Government and the SRC, Japan. Some of the results in this paper were obtained using the computing resources of the Synergy Center, Tohoku University.","Shiroishi Y., Fukuda K., Tagawa I., Iwasaki H., Takenoiri S., Tanaka H., Mutoh H., Yoshikawa N., Future options for HDD storage, IEEE Trans. Magn., 45, 10, pp. 3816-3822, (2009); Wood R., Williams M., Kavcic A., Miles J., The feasibility of magnetic recording at 10 terabits per square inch on conventional media, IEEE Trans. Magn., 45, 2, pp. 917-923, (2009); Kasiraj P., New R., Souza J., Williams M., System and Method for Writing to HDD in Bands, (2005); Greaves S., Kanai Y., Muraoka H., Shingled recording for 2-3 Tbit/in 2, IEEE Trans. Magn., 45, 10, pp. 3823-3831, (2009); Kanai Y., Hirasawa K., Jinbo Y., Yoshida K., Greaves S., Muraoka H., Write head modeling for shingled recording, Proc. Int. Magn. Conf., (2009); Miura K., Yamamoto E., Muraoka H., Estimation of maximum track density in shingled writing, IEEE Trans. Magn., 45, 10, pp. 3722-3725, (2009); JMAG-Studio Commercial Software; Takano K., Guan L., Zhou Y., Liu Y., Smyth J., Dovek M., Micromagnetic simulation of various pole tip design PMR heads, J. Appl. Phys., 105, 7, (2009); Magpar Micromagnetic Software; Song S., Guan L., Mao S., Micromagnetic analysis of adjacent track erasure of wrapped-around shielded PMR writers, IEEE Trans. Magn., 45, 10, pp. 3730-3732, (2009); Kanai Y., Saiki M., Hirasawa K., Tsukamoto T., Yoshida K., Greaves S.J., Muraoka H., Micromagnetic recording field analysis of single-pole-type heads for bit patterned media, J. Magn. Magn. Mater., 320, (2008)","Y. Kanai; Niigata Institute of Technology, Kashiwazaki, Niigata 945-1195, Japan; email: kanai@iee.niit.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-79961231976" +"Kudo K.; Kawaguchi Y.","Kudo, Kazue (9841682600); Kawaguchi, Yuki (12545755800)","9841682600; 12545755800","Dissipative hydrodynamic equation of a ferromagnetic Bose-Einstein condensate: Analogy to magnetization dynamics in conducting ferromagnets","2011","Physical Review A - Atomic, Molecular, and Optical Physics","84","4","043607","","","","19","10.1103/PhysRevA.84.043607","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80053613613&doi=10.1103%2fPhysRevA.84.043607&partnerID=40&md5=333109f03ed9afdb282829b21f03c038","Division of Advanced Sciences, Ochadai Academic Production, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, 2-1-1 Ohtsuka, Japan; Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, 7-3-1 Hongo, Japan","Kudo K., Division of Advanced Sciences, Ochadai Academic Production, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610, 2-1-1 Ohtsuka, Japan; Kawaguchi Y., Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, 7-3-1 Hongo, Japan","The hydrodynamic equation of a spinor Bose-Einstein condensate (BEC) gives a simple description of spin dynamics in the condensate. We introduce the hydrodynamic equation of a ferromagnetic BEC with dissipation originating from the energy dissipation of the condensate. The dissipative hydrodynamic equation has the same form as an extended Landau-Lifshitz-Gilbert (LLG) equation, which describes the magnetization dynamics of conducting ferromagnets in which localized magnetization interacts with spin-polarized currents. Employing the dissipative hydrodynamic equation, we demonstrate the magnetic domain pattern dynamics of a ferromagnetic BEC in the presence and absence of a current of particles, and discuss the effects of the current on domain pattern formation. We also discuss the characteristic lengths of domain patterns that have domain walls with and without finite magnetization. © 2011 American Physical Society.","","Domain walls; Dynamics; Energy dissipation; Ferromagnetic materials; Hydrodynamics; Magnetic domains; Magnetization; Magnets; Spin dynamics; Statistical mechanics; Steam condensers; Bose-Einstein condensates; Characteristic length; Domain pattern; Ferromagnets; Hydrodynamic equations; Landau-Lifshitz-Gilbert equations; Magnetic domain patterns; Magnetization dynamics; Spin-polarized currents; Ferromagnetism","","","","","Japan Society for the Promotion of Science, JSPS, (22740265)","","Leggett A.J., Rev. Mod. Phys., 47, (1975); Borovik-Romanov A.S., Bunkov Y.M., Dmitriev V.V., Mukharskiy Y.M., Sergatskov D.A., Phys. Rev. Lett., 62, (1989); Sadler L.E., Higbie J.M., Leslie S.R., Vengalattore M., Stamper-Kurn D.M., Spontaneous symmetry breaking in a quenched ferromagnetic spinor Bose-Einstein condensate, Nature, 443, 7109, pp. 312-315, (2006); Vengalattore M., Leslie S.R., Guzman J., Stamper-Kurn D.M., Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate, Physical Review Letters, 100, 17, (2008); Vengalattore M., Guzman J., Leslie S.R., Serwane F., Stamper-Kurn D.M., Phys. Rev. A, 81, (2010); Lamacraft A., Phys. Rev. A, 77, (2008); Kudo K., Kawaguchi Y., Phys Rev. A, 82, (2010); Barnett R., Podolsky D., Refael G., Phys. Rev. B, 80, (2009); Cherng R.W., Demler E., Phys. Rev. A, 83, (2011); Cherng R.W., Demler E., Phys. Rev. A, 83, (2011); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Bazaliy Ya.B., Jones B.A., Zhang S.-C., Phys. Rev. B, 57, (1998); Li Z., Zhang S., Phys. Rev. Lett., 92, (2004); Ho T.-L., Shenoy V.B., Phys. Rev. Lett., 77, (1996); Nakahara M., Isoshima T., MacHida K., Ogawa S., Ohmi T., Physica B, 284-288, (2000); Isoshima T., Nakahara M., Ohmi T., MacHida K., Phys. Rev. A, 61, (2000); Mermin N.D., Ho T.-L., Phys. Rev. Lett., 36, (1976); Lakshmanan M., Phil. Trans. R. Soc. A, 369, (2011); Tatara G., Kohno H., Shibata J., Phys. Rep., 468, (2008); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Thiaville A., Nakatani Y., Miltat J., Suzuki Y., Micromagnetic understanding of current-driven domain wall motion in patterned nanowires, Europhysics Letters, 69, 6, pp. 990-996, (2005); Wong C.H., Tserkovnyak Y., Phys. Rev. B, 80, (2009); Kohno H., Tatara G., Shibata J., J. Phys. Soc. Jpn., 75, (2006); Tserkovnyak Y., Skadsem H.J., Brataas A., Bauer G.E.W., Current-induced magnetization dynamics in disordered itinerant ferromagnets, Physical Review B - Condensed Matter and Materials Physics, 74, 14, (2006); Barnes S.E., Maekawa S., Current-spin coupling for ferromagnetic domain walls in fine wires, Physical Review Letters, 95, 10, pp. 1-4, (2005); He J., Li Z., Zhang S., Current-driven vortex domain wall dynamics by micromagnetic simulations, Physical Review B - Condensed Matter and Materials Physics, 73, 18, (2006); Shibata J., Nakatani Y., Tatara G., Kohno H., Otani Y., Current-induced magnetic vortex motion by spin-transfer torque, Physical Review B - Condensed Matter and Materials Physics, 73, 2, pp. 1-4, (2006); Yamaguchi A., Ono T., Nasu S., Miyake K., Mibu K., Shinjo T., Phys. Rev. Lett., 92, (2004); Yamaguchi A., Ono T., Nasu S., Miyake K., Mibu K., Shinjo T., Phys. Rev. Lett., 96, (2006); Klaui M., Jubert P.-O., Allenspach R., Bischof A., Bland J.A.C., Faini G., Rudiger U., Vaz C.A.F., Vila L., Vouille C., Direct observation of domain-wall configurations transformed by spin currents, Physical Review Letters, 95, 2, pp. 1-4, (2005); Heyne L., Et al., Phys. Rev. Lett., 105, (2010); Ye J., Kim Y.B., Millis A.J., Shraiman B.I., Majumdar P., Tes anovic Z., Phys. Rev. Lett., 83, (1999); Onoda S., Nagaosa N., Phys. Rev. Lett., 90, (2003); Onoda M., Tatara G., Nagaosa N., Anomalous hall effect and skyrmion number in real and momentum spaces, Journal of the Physical Society of Japan, 73, 10, pp. 2624-2627, (2004); Taguchi K., Tatara G., Phys. Rev. B, 79, (2009); Kawaguchi Y., Saito H., Ueda M., Einstein-de Haas effect in dipolar Bose-Einstein condensates, Physical Review Letters, 96, 8, pp. 1-4, (2006); Kawaguchi Y., Saito H., Ueda M., Spontaneous circulation in ground-state spinor dipolar Bose-Einstein condensates, Physical Review Letters, 97, 13, (2006); Yi S., Pu H., Spontaneous spin textures in dipolar spinor condensates, Physical Review Letters, 97, 2, (2006); Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Hubert A., Schafer R., Magnetic Domains, (1998); Deutsch J.M., Mai T., Mechanism for nonequilibrium symmetry breaking and pattern formation in magnetic films, Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 72, 1, pp. 1-11, (2005); Gerbier F., Widera A., Folling S., Mandel O., Bloch I., Phys. Rev. A, 73, (2006); Tsubota M., Kasamatsu K., Ueda M., Phys. Rev. A, 65, (2002); Kasamatsu K., Tsubota M., Ueda M., Phys. Rev. A, 67, (2003); Choi S., Morgan S.A., Burnett K., Phys. Rev. A, 57, (1998); Kawaguchi Y., Saito H., Kudo K., Ueda M., Phys. Rev. A, 82, (2010); Ezawa M., Phys. Rev. Lett., 105, (2010); Lin Y.-J., Compton R.L., Jimenez-Garcia K., Porto J.V., Spielman I.B., Nature (London), 462, (2009)","","","","","","","","","10941622","","PLRAA","","English","Phys Rev A","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-80053613613" +"Zuo W.-L.; Qiao L.; Chi X.; Wang T.; Li F.-S.","Zuo, Wen-Liang (23986632500); Qiao, Liang (57210589201); Chi, Xiao (56825200900); Wang, Tao (58127626200); Li, Fa-Shen (21741072200)","23986632500; 57210589201; 56825200900; 58127626200; 21741072200","Complex permeability and microwave absorption properties of planar anisotropy Ce2Fe17N3-δ particles","2011","Journal of Alloys and Compounds","509","22","","6359","6363","4","45","10.1016/j.jallcom.2011.03.105","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79955640839&doi=10.1016%2fj.jallcom.2011.03.105&partnerID=40&md5=cfd1546c36c0a76f25e9b2b847a88877","Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China","Zuo W.-L., Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China; Qiao L., Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China; Chi X., Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China; Wang T., Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China; Li F.-S., Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China","The effective complex permeability of Ce2Fe17N 3-δ particles/epoxy resin composites with various volume concentrations p were measured in the frequency range of 0.1-15 GHz. The intrinsic quasi-static permeability μ′0,i of Ce 2Fe17N3-δ particle was calculated by Bruggerman's (BG) effective medium theory. Meanwhile, the effective quasi-static permeability μ′0,e of composites were calculated by the BG theory and modified Bruggerman's (MBG) effective medium theory, respectively. Through analyzing the experiment data, the effective shape factors of Ce 2Fe17N3-δ composites were determined. The intrinsic natural resonance frequency of Ce2Fe17N 3-δ was obtained using Landua-Lifshitz-Gilbert (LLG) equation. The minimum EM absorbing values with RL ≤ -30 dB are observed for all the volume concentrations. © 2011 Elsevier B.V. All rights reserved.","Ce2Fe17N3-δ; Effective medium theory; Intrinsic permeability; Planar anisotropy","Natural frequencies; Resins; Complex permeability; Effective medium theories; Effective medium theory; Experiment data; Frequency ranges; Intrinsic permeability; Microwave absorption properties; Natural resonance frequencies; Planar anisotropy; Quasi-static; Resin composites; Shape factor; Volume concentration; Anisotropy","","","","","defense industrial technology development program, (A142008174); National Natural Science Foundation of China, NSFC, (10774061); National Natural Science Foundation of China, NSFC","Authors wish to thank Physics Department of Lanzhou University for the SEM images of the samples. This work is supported by National Natural Science foundations of China (grant no. 10774061 ) and defense industrial technology development program (grant no. A142008174 ).","Naito Y., Suetake K., IEEE Trans. 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Qiao; Key Laboratory of Magnetism and Magnetic Materials, Ministry of Education, Lanzhou University, Lanzhou 730000, China; email: qiaoliang@lzu.edu.cn","","","","","","","","09258388","","JALCE","","English","J Alloys Compd","Article","Final","","Scopus","2-s2.0-79955640839" +"Kötzler J.; Görlitz D.; Wiekhorst F.","Kötzler, Jürgen (6701377921); Görlitz, Detlef (6603245445); Wiekhorst, Frank (6506199205)","6701377921; 6603245445; 6506199205","Strong spin-orbit-induced Gilbert damping and g -shift in iron-platinum nanoparticles","2007","Physical Review B - Condensed Matter and Materials Physics","76","10","104404","","","","9","10.1103/PhysRevB.76.104404","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34548560249&doi=10.1103%2fPhysRevB.76.104404&partnerID=40&md5=1b0b1fdc30e2ebb60083145588acda38","Institut für Angewandte Physik, Zentrum für Mikrostrukturforschung, Universität Hamburg, D-20355 Hamburg, Jungiusstrasse 11, Germany","Kötzler J., Institut für Angewandte Physik, Zentrum für Mikrostrukturforschung, Universität Hamburg, D-20355 Hamburg, Jungiusstrasse 11, Germany; Görlitz D., Institut für Angewandte Physik, Zentrum für Mikrostrukturforschung, Universität Hamburg, D-20355 Hamburg, Jungiusstrasse 11, Germany; Wiekhorst F., Institut für Angewandte Physik, Zentrum für Mikrostrukturforschung, Universität Hamburg, D-20355 Hamburg, Jungiusstrasse 11, Germany","The shape of ferromagnetic resonance spectra of highly dispersed, chemically disordered Fe0.2 Pt0.8 nanospheres is perfectly described by the solution of the Landau-Lifshitz-Gilbert (LLG) equation excluding effects by crystalline anisotropy and superparamagnetic fluctuations. Upon decreasing temperature, the LLG damping α(T) and a negative g -shift, g(T)- g0, increase proportional to the particle magnetic moments determined from the Langevin analysis of the magnetization isotherms. These features are explained by the scattering of the q→0 magnon from an electron-hole (e h) pair mediated by the spin-orbit coupling, while the sd exchange can be ruled out. The large saturation values, α(0)=0.76 and g(0) g0 -1=-0.37, indicate the dominance of an overdamped 1 meV e h pair which seems to originate from the discrete levels of the itinerant electrons in the dp =3 nm nanoparticles. © 2007 The American Physical Society.","","","","","","","","","Woltersdorf G., Buess M., Heinrich B., Back C.H., Phys. Rev. Lett., 95, (2005); Koopmans B., Ruigrok J.J.M., Dalla Longa F., De Jonge W.J.M., Phys. Rev. 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Mater., 272-276, (2004); Antoniak C., Lindner J., Spasova M., Sudfeld D., Acet M., Farle M., Fauth K., Wiedwald U., Boyen H.-G., Ziemann P., Wilhelm F., Rogalev A., Sun S., Phys. Rev. Lett., 97, (2006); Livingston J.D., Bean C.P., J. Appl. Phys., 30, (1959); De Biasi R.S., Devezas T.C., J. Appl. Phys., 49, (1978); Heinrich B., Fraitova D., Kambersky V., Phys. Status Solidi, 23, (1967); Tsnerkovnyak Y., Fiete G.A., Halperin B.I., Appl. Phys. Lett., 84, (2004); Costa A.T., Muniz R.B., Mills D.L., Phys. Rev. B, 73, (2006); Turov E.A., Ferromagnetic Resonance, (1966); Gueron S., Deshmukh M.M., Myers E.B., Ralph D.C., Phys. Rev. Lett., 83, (1999); Kleff S., Von Delft J., Deshmukh M.M., Ralph D.C., Phys. Rev. B, 64, (2001); Kulatov E.T., Uspenskii Y.-A., Halilov S.-V., J. Magn. Magn. Mater., 163, (1996)","","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-34548560249" +"Fashami M.S.; Roy K.; Atulasimha J.; Bandyopadhyay S.","Fashami, Mohammad Salehi (55037499600); Roy, Kuntal (14825673500); Atulasimha, Jayasimha (6508238509); Bandyopadhyay, Supriyo (57203099871)","55037499600; 14825673500; 6508238509; 57203099871","Magnetization dynamics, Bennett clocking and associated energy dissipation in multiferroic logic","2011","Nanotechnology","22","15","155201","","","","98","10.1088/0957-4484/22/15/155201","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79952660579&doi=10.1088%2f0957-4484%2f22%2f15%2f155201&partnerID=40&md5=513d95024343cfbc5856809272b0232c","Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","Fashami M.S., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Roy K., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Atulasimha J., Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; Bandyopadhyay S., Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States","It has been recently shown that the magnetization of a multiferroic nanomagnet, consisting of a magnetostrictive layer elastically coupled to a piezoelectric layer, can be rotated by a large angle if a tiny voltage of a few tens of millivolts is applied to the piezoelectric layer. The potential generates stress in the magnetostrictive layer and rotates its magnetization by ∼ 90° to implement Bennett clocking in nanomagnetic logic chains. Because of the small voltage needed, this clocking method is far more energy efficient than those that would employ spin transfer torque or magnetic fields to rotate the magnetization. In order to assess if such a clocking scheme can also be reasonably fast, we have studied the magnetization dynamics of a multiferroic logic chain with nearest-neighbor dipole coupling using the Landau-Lifshitz-Gilbert (LLG) equation. We find that clock rates of 2.5GHz are feasible while still maintaining the exceptionally high energy efficiency. For this clock rate, the energy dissipated per clock cycle per bit flip is ∼ 52 000kT at room temperature in the clocking circuit for properly designed nanomagnets. Had we used spin transfer torque to clock at the same rate, the energy dissipated per clock cycle per bit flip would have been ∼ 4 × 108kT, while with current transistor technology we would have expended ∼ 106kT. For slower clock rates of 1GHz, stress-based clocking will dissipate only ∼ 200kT of energy per clock cycle per bit flip, while spin transfer torque would dissipate about 108kT. This shows that multiferroic nanomagnetic logic, clocked with voltage-generated stress, can emerge as a very attractive technique for computing and signal processing since it can be several orders of magnitude more energy efficient than current technologies. © 2011 IOP Publishing Ltd.","","Energy dissipation; Energy efficiency; Magnetic fields; Magnetization; Magnetostrictive devices; Nanomagnetics; Piezoelectricity; Signal processing; Bit-flips; Clock cycles; Clock rate; Clocking schemes; Current technology; Dipole coupling; Energy efficient; High energy efficiency; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Magnetostrictive layers; Multiferroics; Nanomagnets; Nearest-neighbors; Orders of magnitude; Piezoelectric layers; Room temperature; Spin transfer torque; Clocks","","","","","","","Cavin R.K., Zhirnov V.V., Hutchby J.A., Bourianoff G.I., Proc. IEEE, 91, 11, (2003); Salahuddin S., Datta S., Appl. Phys. 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Struct., 19, 5, (2008); Walowski J., Djorjevic Kaufman M., Lenk B., Hamann C., McCord J., Munzenberg M., J. Phys. D: Appl. Phys., 41, 16, (2008); Run A.M.J.G., Terrell D.R., Scholing J.H., J. Mater. Sci., 9, 10, (1974); Ryu J., Priya S., Carazo A.V., Uchino K., Kim H.-E., J. Am. Ceram. Soc., 84, 12, (2001); Pertsev N.A., Kohlstedt H., Appl. Phys. Lett., 95, 16, (2009); D'Souza N., Atulasimha J., Bandyopadhyay S., (2011)","J. Atulasimha; Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States; email: jatulasimha@vcu.edu","","","","","","","","13616528","","NNOTE","","English","Nanotechnology","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-79952660579" +"Takahashi S.; Kai T.; Shimomura N.; Ueda T.; Amano M.; Yoshikawa M.; Kitagawa E.; Asao Y.; Ikegawa S.; Kishi T.; Yoda H.","Takahashi, Shigeki (8574354300); Kai, Tadashi (7102037898); Shimomura, Naoharu (7004812116); Ueda, Tomomasa (7403983363); Amano, Minoru (7201830402); Yoshikawa, Masatoshi (24726099400); Kitagawa, Eiji (23466830700); Asao, Yoshiaki (7003487920); Ikegawa, Sumio (7102780384); Kishi, Tatsuya (55586719100); Yoda, Hiroaki (7005803501)","8574354300; 7102037898; 7004812116; 7403983363; 7201830402; 24726099400; 23466830700; 7003487920; 7102780384; 55586719100; 7005803501","Ion-beam-etched profile control of MTJ cells for improving the switching characteristics of high-density MRAM","2006","IEEE Transactions on Magnetics","42","10","","2745","2747","2","26","10.1109/TMAG.2006.878862","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85008013253&doi=10.1109%2fTMAG.2006.878862&partnerID=40&md5=0dc5adedc3d9789f3aac952dfedaa3d6","Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; System Devices Research Laboratories, NEC Corporation, Kanagawa 229-1198, Japan","Takahashi S., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan, System Devices Research Laboratories, NEC Corporation, Kanagawa 229-1198, Japan; Kai T., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan, System Devices Research Laboratories, NEC Corporation, Kanagawa 229-1198, Japan; Shimomura N., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan, System Devices Research Laboratories, NEC Corporation, Kanagawa 229-1198, Japan; Ueda T., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Amano M., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Yoshikawa M., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Kitagawa E., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Asao Y., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Ikegawa S., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Kishi T., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan; Yoda H., Corporate Research and Development Center, Toshiba Corporation, Kawasaki 212-8582, Japan","The effect of the reduction of the sidewall redeposition layer of magnetic materials is investigated for submicron-patterned magnetic random access memory (MRAM) cells. The sidewall redeposition layer is made at the first etch step of a magnetic tunnel junction (MTJ) with ion beam etching (IBE) in the case that the sidewall angle of a hard mask is steep. By controlling the etched profile at the time of the first IBE step, formation of the redeposition layer is prevented. Functional test results of 1-Kb MRAM arrays show that the sidewall redeposition layer enlarges fluctuation of switching current, and reduces the write operation region. The effect of the side-wall redeposition on the switching characteristics of MRAM arrays is explained qualitatively by micromagnetic simulation solving the Landau-Lifshitz-Gilbert (LLG) equation. © 2006, IEEE. All rights reserved.","Ion beam etching (IBE); magnetic random access memory (MRAM); magnetic tunnel junction (MTJ)","","","","","","","","Kai T., Et al., IEDM Tech. Dig., pp. 583-586, (2004); Yoshikawa M., Et al., Abstracts 50th Magnetism Magnetic Materials (MMM) Conf., (2005); Yoshikawa M., Et al., J. Appl. Phys., 97, pp. 10P508-1-10P508-3, (2005); Nakajima K., Amano M., Ueda T., Takahashi S., Magnetic memory device and method of manufacturing the same, U.S. Patent 6 965 138, (2005); Gallagher W.J., Et al., J. Appl. Phys., 81, pp. 3741-3746, (1997); Chapman R.E., J. Mater. Sci., 12, pp. 1125-1133, (1977); Lee R.E., J. Vac. Sci. Technol., 16, pp. 164-170, (1979); Walsh M.E., Hao Y., Ross C.A., Smith H.I., J. Vac. Sci. Technol. B, 18, pp. 3539-3543, (2000); Light R.W., Bell H.B., J. Electrochem. Soc., 130, pp. 1567-1571, (1983)","","","","","","","","","00189464","","","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-85008013253" +"Yuan L.; Jiang J.J.; Di Y.; Bie S.; He H.","Yuan, Lin (55682960200); Jiang, Jianjun (7404829902); Di, Yongjiang (16204795900); Bie, Shaowei (22936663200); He, Huahui (7402292192)","55682960200; 7404829902; 16204795900; 22936663200; 7402292192","Micromagnetic simulation of the magnetic dispersion angle and effective damping factor for the single-phase soft magnetic films","2008","Journal of Magnetism and Magnetic Materials","320","7","","1393","1397","4","3","10.1016/j.jmmm.2007.11.025","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-39949084694&doi=10.1016%2fj.jmmm.2007.11.025&partnerID=40&md5=2a78276bc7cfabae81f16b19f9799ae8","Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China","Yuan L., Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China; Jiang J.J., Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China; Di Y., Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China; Bie S., Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China; He H., Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China","The micromagnetic structure of the single-phase soft magnetic films was simulated using the model of two-dimensional hexagonal lattices by micromagnetic method. The typical micromagnetic ripple structure of magnetic films was obtained. Thus, the magnetic dispersion angle was calculated from the static magnetic structure of the film. Furthermore, the relationship between the magnetic dispersion angles and the corresponding magnetic parameters of the film was discussed. The technique also demonstrated the microwave permeability of the films and the magnetic spectra well fitted by the permeability equation, which was deduced from the Landau-Lifshitz-Gilbert (LLG) function when the film was considered as a single domain. The fitting data of effective damping factor as a function of the magnetic dispersion angle were investigated. © 2007 Elsevier B.V. All rights reserved.","Effective damping factor; Magnetic dispersion angle; Micromagnetic; Ripple theory","Computer simulation; Damping; Magnetic permeability; Magnetic structure; Microwaves; Soft magnetic materials; Effective damping factors; Magnetic dispersion angle; Micromagnetic simulation; Microwave permeability; Ripple theory; Magnetic films","","","","","Elitist in Natural Science Foundation of Hubei Province, (2005ABB002); National Natural Science Foundation of China, NSFC, (50371029, 50771047); Program for New Century Excellent Talents in University, NCET, (NCET-04-0702)","The financial supports from National Natural Science Foundation of China (Grant no. 50371029, 50771047), New Century Excellent Talents in University (Grant no. NCET-04-0702) and Elitist in Natural Science Foundation of Hubei Province (Grant no. 2005ABB002) are acknowledged.","Suzuki T., Wilts C.H., J. Appl. Phys., 39, (1968); Liu Z., Shindo D., Ohnuma S., Fujimori H., J. Magn. Magn. Mater., 262, (2003); Stoner E.C., Wohlfarth E.P., Philos. Trans. R. Soc. A, 250, (1955); Hoffmann H., IEEE Trans. Magn., 4, (1968); Berkov D.V., Gorn N.L., Phys. Rev. B, 57, (1998); Scholz W., Fidler J., Schrefl T., Suess D., Dittrich R., Forster H., Tsiantos V., Comp. Mater. Sci., 28, (2003); McMichael R.D., Twisselmann D.J., Phys. Rev. Lett., 90, (2003); Chechenin N.G., Phys. Sol. State, 46, (2004)","J.J. Jiang; Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, HuBei 430074, China; email: jiangjj@mail.hust.edu.cn","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-39949084694" +"Jiang C.; Xue D.; Sui W.","Jiang, Changjun (55705027800); Xue, Desheng (55447216200); Sui, Wenbo (26656238500)","55705027800; 55447216200; 26656238500","Extracting uniaxial anisotropy of ferromagnetic layer in exchange-biased system","2010","Journal of Magnetism and Magnetic Materials","322","22","","3676","3679","3","4","10.1016/j.jmmm.2010.07.024","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77957839457&doi=10.1016%2fj.jmmm.2010.07.024&partnerID=40&md5=5669f9a7c401f835bcd483b9e6a2020c","Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China","Jiang C., Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China; Xue D., Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China; Sui W., Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China","Effective anisotropy of the ferromagnetic pinned layer of ferro(FM)-antiferromagnetic (AF)-coupled NiFe(FM)/FeMn(AF) exchange-biased system was investigated in a broad frequency range (100 MHz5 GHz) using a complex permeability spectrum. The exchange bias and effective uniaxial anisotropy fields of the thin film have been computed theoretically using the LandauLifschitzGilbert (LLG) equation. From the measurements, uniaxial anisotropy of the pinned FM layer has been extracted to understand the nature of the exchange bias in the system. It is found that the uniaxial anisotropy field of NiFe layer when exchange biased with the AF layer increases from 5 to 15 Oe at different external magnetic fields. © 2010 Elsevier B.V. All rights reserved.","Exchange bias; High-frequency permeability; Uniaxial anisotropy","Anisotropy; Antiferromagnetism; Ferromagnetic materials; Ferromagnetism; Iron compounds; Magnetic fields; Antiferromagnetics; Broad frequency range; Complex permeability spectra; Effective anisotropy; Exchange bias; Exchange-biased systems; External magnetic field; Ferromagnetic layers; High-frequency permeability; Pinned layers; Uniaxial anisotropy; Uniaxial anisotropy fields; Magnetic properties","","","","","National Natural Science Foundation of China, NSFC, (50902064, 50925103); Ministry of Education of the People's Republic of China, MOE, (309027)","We thank Dr. Veerakumar Venugopal from University of Colorado for helping with the English revision. This work was supported by the NSFC (Grant Nos. 50925103 and 50902064 ) and the Keygrant Project of Chinese Ministry of Education (Grant No. 309027 ) of P.R. China.","Wei Z., Sharma A., Nunez A.S., Haney P.M., Duine R.A., Bass J., MacDonald A.H., Tsoi M., Phys. Rev. Lett., 98, (2007); Leighton C., Nogus J., Jnsson-Kerman B.J., Schuller I.K., Phys. Rev. Lett., 84, (2000); Wang L., You B., Yuan S.J., Du J., Zou W.Q., Hu A., Zhou S.M., Phys. Rev. B, 66, (2002); Jensen P.J., Bennenmann K.H., Surf. Sci. Rep., 61, (2006); Jiang C.J., Xue D.S., Fan X.L., Guo D.W., Liu Q.F., Nanotechnology, 18, (2007); Blamire M.G., Ali M., Leung C.W., Marrows C.H., Hickey B.J., Phys. Rev. Lett., 98, (2007); Choo D., Chantrell R.W., Lambertom R., Johnston A., Grady K.O., J. Appl. Phys., 101, (2007); Qiu X.P., Yang D.Z., Zhou S.M., Chantrell R., O'Grady K., Nowak U., Du J., Bai X.J., Sun L., Phys. Rev. Lett., 101, (2008); Hoffmann A., Grimsditch M., Pearson J.E., Nogues J., MacEdo W.A.A., Schuller I.K., Phys. Rev. B, 67, (2003); Spenato D., Castel V., Pogossian S.P., Dekadjevi D.T., Youssef J.B., Appl. Phys. Lett., 91, (2007); McCord J., Kaltofen R., Gemming T., Hhne R., Schultz L., Phys. Rev. B, 75, (2007); Kuanr B.K., Maat S., Chandrashekariaih S., Veerakumar V., Camley R.E., Celinshi Z., J. Appl. Phys., 103, (2008); Geshev J., Nicolodi S., Pereira L.G., Nagamine L.C.C.M., Schmidt J.E., Deranlot C., Petroff F., Rodrgurz-Surez R.L., Azevedo A., Phys. Rev. B, 75, (2007); Xue D.S., Fan X.L., Jiang C.J., Appl. Phys. Lett., 89, (2006); Yan Liu L.C., Tan C.Y., Liu H.J., Ong C.K., Rev. Sci. Instrum., 76, (2005); Queste S., Dubourg S., Acher O., Barholz K.U., Mattheis R., J. Appl. Phys., 95, (2004); Xue D.S., Li F.S., Fan X.L., Wen F.S., Chin. Phys. Lett., 25, (2008); Speriosu V.S., Parkin S.S.P., Wilts C.H., IEEE Trans. Magn., 23, (1987); Chung S.H., Hoffmann A., Grimsditch M., Phys. Rev. B, 71, (2005); Kaiser U., Schwarz A., Wiesendanger R., Nature, 446, (2007); Alsmadi A.M., Velthuis S.G.E.T., Felcher G.P., Kim C.G., J. Appl. Phys., 101, (2007)","C. Jiang; Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000, China; email: jiangchj@lzu.edu.cn","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-77957839457" +"Zhang S.; Zhang S.S.-L.","Zhang, Shufeng (53165346300); Zhang, Steven S.-L. (35202606300)","53165346300; 35202606300","Generalization of the Landau-Lifshitz-Gilbert equation for conducting ferromagnets","2009","Physical Review Letters","102","8","086601","","","","172","10.1103/PhysRevLett.102.086601","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-61649103366&doi=10.1103%2fPhysRevLett.102.086601&partnerID=40&md5=efce9dfa56481033fb8fcd2214698863","Department of Physics, University of Arizona, Tucson, AZ 85721, United States","Zhang S., Department of Physics, University of Arizona, Tucson, AZ 85721, United States; Zhang S.S.-L., Department of Physics, University of Arizona, Tucson, AZ 85721, United States","We propose an extension of the Landau-Lifshitz-Gilbert (LLG) equation by explicitly including the role of conduction electrons in magnetization dynamics of conducting ferromagnets. The temporal and spatial dependent magnetization order parameter m(r,t) generates both electrical and spin currents that provide dissipation of the energy and angular momentum of the processing magnet. The resulting LLG equation contains highly spatial dependence of damping term and thus micromagnetic simulations based on the standard LLG equation should be reexamined for magnetization dynamics involving narrow domain walls and spin waves with short wavelengths. © 2009 The American Physical Society.","","Domain walls; Dynamics; Ferromagnetic materials; Ferromagnetism; Magnetization; Magnets; Multilayers; Spin waves; Conduction electrons; Ferromagnets; Landau-Lifshitz-Gilbert equations; Llg equations; Magnetization dynamics; Micro-magnetic simulations; Order parameters; Short wavelengths; Spatial dependences; Spin currents; Spin dynamics","","","","","","","Gilbert T.L., IEEE Trans. Magn., 40, (2004); Slonczewski J., J. Magn. Magn. Mater., 159, (1996); Rossi E., Heinonen O.G., MacDonald A.H., Phys. Rev. B, 72, (2005); Rebei A., Parker G.J., Phys. Rev. B, 67, (2003); Smith N., J. Appl. Phys., 90, (2001); Safonov V.L., Bertram H.N., J. Appl. Phys., 94, (2003); Kunes J., Kambersky V., Phys. Rev. B, 65, (2002); Gilmore K., Idzerda Y.U., Stiles M.D., Phys. Rev. Lett., 99, (2007); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Halperin B.I., Rev. Mod. Phys., 77, (2005); Volovik G.E., J. Phys. C, 20, (1987); Papanicolaou N., Tomaras T.N., Nucl. Phys., 360, (1991); Yang S.A., Beach G.S.D., Knutson C., Xiao D., Niu Q., Tsoi M., Erskine J.L., Phys. Rev. Lett., 102, (2009); Tserkovnyak Y., Mecklenburg M., Phys. Rev. B, 77, (2008); Barnes S.E., Maekawa S., Phys. Rev. Lett., 98, (2007); Saslow W.M., Phys. Rev. B, 76, (2007); Bazaliy Y.B., Jones B.A., Zhang S.C., Phys. Rev. B, 57, (1998); Duine R.A., Phys. Rev. B, 79, (2009); Tserkovnyak Y., Wong C.H., Phys. Rev. B, 79, (2009); Levy P.M., Zhang S., Phys. Rev. Lett., 79, (1997); Foros J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. B, 78, (2008); Hankiewicz E.M., Vignale G., Tserkovnyak Y., Phys. Rev. B, 78, (2008); Schryer N.L., Walker L.R., J. Appl. Phys., 45, (1974); He J., Zhang S., Appl. Phys. Lett., 90, (2007)","","","","","","","","","10797114","","PRLTA","","English","Phys Rev Lett","Article","Final","","Scopus","2-s2.0-61649103366" +"Aziz M.M.","Aziz, M.M. (7103236089)","7103236089","Sub-nanosecond electromagnetic-micromagnetic dynamic simulations using the finite-difference time-domain method","2009","Progress In Electromagnetics Research B","","15","","1","29","28","16","10.2528/PIERB09042304","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-69949106008&doi=10.2528%2fPIERB09042304&partnerID=40&md5=626a95688f6b6f6954a4e22d947f608b","School of Engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, Harrison Building, United Kingdom","Aziz M.M., School of Engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, Harrison Building, United Kingdom","This paper presents an efficient and simple approach of implementing the Landau-Lifshitz-Gilbert (LLG) equation of magnetisation motion within the Finite-difference Time-domain (FDTD) method. This combined electromagnetic-micromagnetic simulation technique is particularly important for modeling electromagnetic interaction with lossy magnetic material in the presence of current and magnetic sources, particularly at very high frequencies. The efficient implementation involves simple two-point spatial interpolations that are applicable to two and three-dimensional FDTD grids, and uses a stable iterative algorithm for the time integration of the LLG equation. A ferromagnetic resonance numerical experiment on a rectangular Permalloy prism excited through its cross-section by a non-uniform pulse field from a transmission line was carried out for the purpose of verifying the combined FDTD-LLG computations. The numerical results were in good agreement with linearised analytical solutions of the LLG equation for uniform and non-uniform precession modes. This paper also presents a brief investigation on the use of non-staggered FDTD grid schemes to model magnetic material using the LLG equation, and indicates that the classical FDTD staggered scheme offers simplicity in implementation and more accuracy for modeling wave interaction with lossy magnetic material than the non-staggered schemes based on Maxwell's equations formulation.","","","","","","","","","Taflove A., Hagness S.C., Computational Electrodynamics: The Finite-difference Time-domain Method, (2000); Kunz K.S., Luebbers R.J., The Finite Difference Time Domain Method for Electromagnetics, (1993); Pereda J.A., Vielva L.A., Vegas A., Prieto A., An extended fdtd method for the treatment of partially magnetized ferrites, IEEE Trans. Magn., 31, pp. 1666-1669, (1995); Pereda J.A., Vielva L.A., Vegas A., Prieto A., A treatment of magnetized ferrites using the FDTD method, IEEE Microwave and Guided Wave Letters, 3, 5, pp. 136-138, (1993); Pereda J.A., Vielva L.A., Solano M.A., Vegas A., Prieto A., FDTD analysis of magnetized ferrites: Application to the calculation of dispersion characteristics of ferrite-loaded waveguides, IEEE Trans. Microwave Theory and Techniques, 43, 2, pp. 350-357, (1995); Zheng G., Chen K., Transient analysis of microstrip lines with ferrite substrate by extended FD-TD method, Int. J. of Infrared and Millimeter Waves, 13, 8, pp. 1115-1125, (1992); Reineix A., Monediere T., Jecko F., Ferrite analysis using the finite-difference time-domain (FDTD) method, Microwave and Optical Technology Letters, 5, 13, pp. 685-686, (1992); Okoniewski M., Okoniewska E., FDTD analysis of magnetized ferrites: A more efficient algorithm, IEEE Microwave and Guided Wave Letters, 4, 6, pp. 169-171, (1994); Vacus O., Vukadinovic N., Dynamic susceptibility computations for thin magnetic films, Journal of Computational and Applied Mathematics, 176, pp. 263-281, (2005); Soohoo R.F., Magnetic Thin Films, (1965); Soohoo R.F., Magnetic Thin Films, (1965); Brown W.F., Micromagnetics, (1978); Yee K.S., Numerical solution of initial boundary value problems involving maxwell's equations in isotropic media, IEEE Transactions on Antennas and Propagations, 14, 3, pp. 302-307, (1966); Berenger J., A perfectly matched layer for the absorption of electromagnetic waves, Journal of Computational Physics, 114, pp. 185-200, (1994); Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Applied Numerical Mathematics, 46, pp. 95-111, (2003); Hicken R.J., Wu J., Observation of ferromagnetic resonance in the time domain, J. Appl. Phys., 85, 8, pp. 4580-4582, (1999); Wu J., Hughes N.D., Moore J.R., Hicken R.J., Excitation and damping of spin excitations in ferromagnetic thin films, Journal of Magnetism and Magnetic Materials, 241, pp. 96-109, (2002); Soohoo R.F., Magnetic Thin Films, (1965); Wagner C.L., Schneider J.B., Divergent fields, charge, and capacitance in FDTD simulations, IEEE Trans. Microwave Theory and Techniques, 46, 12, pp. 2131-2136, (1998); Osborn J.A., Demagnetizing factors of the general ellipsoid, Physical Review, 67, 11-12, pp. 351-357, (1945); Soohoo R.F., Microwave Magnetics, (1985); Smythe W.R., Static and Dynamic Electricity, (1950); Soohoo R.F., Magnetic Thin Films, (1965); Soohoo R.F., Microwave Magnetics, (1985); Soohoo R.F., Microwave Magnetics, (1985); Park J.P., Eames P., Engebretson D.M., Berezovsky J., Crowell P.A., Spatially resolved dynamics of localized spin-wave modes in ferromagnetic wires, Phys. Rev. Lett., 89, 27, (2002); Gubbiotti G., Conti M., Carlotti G., Candeloro P., Fabrizio E.D., Guslienko K.Y., Andre A., Bayer C., Slavin A.N., Magnetic field dependence of quantized and localized spin-wave modes in thin rectangular magnetic dots, J. Phys.: Condens. Matter, 16, pp. 7709-7721, (2004); Aharoni A., Introduction to the Theory of Ferromagnetism, (2000); Zheng F., Chen Z., Zhang J., A finite-difference timedomain method without the courant stability conditions, IEEE Microwave and Guided Wave Letters, 9, 11, pp. 441-443, (1999); Liu Y., Fourier analysis of numerical algorithms for the maxwell equations, J. of Computational Physics, 124, pp. 396-416, (1996); Kunz K.S., Luebbers R.J., The Finite Difference Time Domain Method for Electromagnetics, (1993); De Flavis F., Noro M.G., Diaz R.E., Franceschetti G., Alexopoulos N.G., A time-domain vector potential formulation for the solution of electromagnetic problems, IEEE Microwave and Guided Wave Letters, 8, 9, pp. 310-312, (1998); Liu Q.H., The PSTD algorithm: A time-domain method requiring only two cells per wavelength, Microwave and Optical Technology Letters, 15, 3, pp. 158-165, (1997); Leung W., Chen Y., Transformed-space nonuniform pseudospectral time-domain algorithm, Microwave and Optical Technology Letters, 28, 6, pp. 391-396, (2001)","M.M. Aziz; School of Engineering, Computing and Mathematics, University of Exeter, Exeter EX4 4QF, Harrison Building, United Kingdom; email: M.M.Aziz@ex.ac.uk","","Electromagnetics Academy","","","","","","19376472","","","","English","Prog. Electromagn. Res. B","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-69949106008" +"Tsiantos V.; Miles J.","Tsiantos, Vassilios (36634990100); Miles, Jim (55432704000)","36634990100; 55432704000","Fast micromagnetic simulations using an analytic mathematical model","2006","Physica B: Condensed Matter","372","1-2","","303","307","4","2","10.1016/j.physb.2005.10.072","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-30844437017&doi=10.1016%2fj.physb.2005.10.072&partnerID=40&md5=3650d10db63bfff59e47adb43e57c1f3","Technological Educational Institute of Kavala, Agios Loukas 65404 Kavala, Greece; Department of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom","Tsiantos V., Technological Educational Institute of Kavala, Agios Loukas 65404 Kavala, Greece; Miles J., Department of Computer Science, University of Manchester, Manchester, M13 9PL, United Kingdom","In this paper an analytic mathematical model is presented for fast micromagnetic simulations. In dynamic micromagnetic simulations the Landau-Lifshitz-Gilbert (LLG) equation is solved for the observation of the reversal magnetisation mechanisms. In stiff micromagnetic simulations the large system of ordinary differential equations has to be solved with an appropriate method, such as the Backward Differentiation Formulas (BDF) method, which leads to the solution of a large linear system. The latter is solved efficiently employing matrix-free techniques, such as Krylov methods with preconditioning. Within the Krylov methods framework a product of a matrix times a vector is involved which is usually approximated with directional differences. This paper provides an analytic mathematical model to calculate efficiently this product, leading to more accurate calculations and consequently faster micromagnetic simulations due to better convergence properties. © 2005 Elsevier B.V. All rights reserved.","Krylov methods; Mathematical model; Numerical micromagnetics","Linear systems; Magnetization; Mathematical models; Numerical analysis; Ordinary differential equations; Backward Differentiation Formulas (BDF) method; Krylov methods; Micromagnetic simulations; Numerical micromagnetics; Magnetism","","","","","","","Barrett R., Et al., Templates for the Solution of Linear Systems: Building Blocks for Iterative Methods, (1994); Saad Y., Iterative Methods for Sparse Linear Systems, (1996); Tsiantos V., Numerical Methods for Ordinary Differential Equations in Micromagnetic Simulations, (2000)","V. Tsiantos; Technological Educational Institute of Kavala, Agios Loukas 65404 Kavala, Greece; email: v.tsiantos@computer.org","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-30844437017" +"Nakahata Y.; Todaka T.; Enokizono M.","Nakahata, Yasushi (16029172400); Todaka, Takashi (7006715391); Enokizono, Masato (7102846085)","16029172400; 7006715391; 7102846085","Magnetization process simulation of Nd-Fe-B magnets taking the demagnetization phenomenon into account","2010","Digests of the 2010 14th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC 2010","","","5481476","","","","0","10.1109/CEFC.2010.5481476","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77954775541&doi=10.1109%2fCEFC.2010.5481476&partnerID=40&md5=1e19d9364ca68d0acee1808b83e16eae","Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, 700 Dannoharu, Japan","Nakahata Y., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, 700 Dannoharu, Japan; Todaka T., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, 700 Dannoharu, Japan; Enokizono M., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, 700 Dannoharu, Japan","This paper presents results obtained from a numerical simulation of the magnetization distribution of Nd-Fe-B magnets. In the initial magnetization process, we have used the three-dimensional Variable Magnetization and Stoner-Wohlfarth (VMSW) method. In the residual magnetization process and demagnetization process, we have used the magnetization equation of motion. Magnetization equation of motion can be described by the Landau-Lifshitz-Gilbert (LLG) equation. The calculation results were compared with the measured results to verify the accuracy of the numerical simulation. © 2010 IEEE.","","Computer simulation; Electromagnetic field measurement; Electromagnetic fields; Equations of motion; Magnetization; Magnets; Neodymium; Neodymium alloys; Demagnetization process; Equation of motion; Landau-Lifshitz-Gilbert equations; Magnetization distribution; Magnetization process; Measured results; Nd-Fe-B magnets; Numerical simulation; Residual magnetization; Stoner-Wohlfarth; Demagnetization","","","","","","","Mohri F., A new method for magnetic field computation on anisotropic permanent magnets, International Journal of Applied Electromagnetics in Materials, 3, 4, pp. 241-248, (1993); Nakahata Y., Todaka T., Enokizono M., Magnetization process simulation of anisotropic permanent magnets by using the three-dimensional VMSW method, IEEE Trans. on Magn., 44, pp. 858-861, (2008); Nakatani Y., Uesaka Y., Hayashi H., Direct solution of the Landau-Lifshitz-Gilbert equation for micromagnetics, Japanese Journal of Applied Physics, 20, pp. 2485-2507, (1989)","Y. Nakahata; Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, 700 Dannoharu, Japan; email: y.nakahata@oita-mag.jp","","","IEEE Magnetics Society","14th Biennial IEEE Conference on Electromagnetic Field Computation, CEFC2010","9 May 2010 through 12 May 2010","Chicago, IL","81103","","978-142447059-4","","","English","Dig. Bienn. IEEE Conf. Electromagn. Field Comput., CEFC","Conference paper","Final","","Scopus","2-s2.0-77954775541" +"Scholz W.; Crawford T.M.; Parker G.J.; Clinton T.W.; Ambrose T.; Kaka S.; Batra S.","Scholz, Werner (7102228903); Crawford, T.M. (7102138487); Parker, Gregory J. (7402344444); Clinton, T.W. (7004133254); Ambrose, T. (7003401995); Kaka, Shehzaad (6602167256); Batra, Sharat (7202128856)","7102228903; 7102138487; 7402344444; 7004133254; 7003401995; 6602167256; 7202128856","Fast magnetization switching with circularly polarized fields and short pulses","2008","IEEE Transactions on Magnetics","44","11 PART 1","","3134","3136","2","8","10.1109/TMAG.2008.2001600","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-73849085322&doi=10.1109%2fTMAG.2008.2001600&partnerID=40&md5=6428fae645d3cf26a7fdea51ace2e38c","Seagate Technology, Pittsburgh, PA 15222, United States; University of South Carolina, USC Nanocenter, Columbia, SC 29208, United States; GE Global Research, Niskayuna, NY 12309, United States","Scholz W., Seagate Technology, Pittsburgh, PA 15222, United States; Crawford T.M., University of South Carolina, USC Nanocenter, Columbia, SC 29208, United States; Parker G.J., GE Global Research, Niskayuna, NY 12309, United States; Clinton T.W., Seagate Technology, Pittsburgh, PA 15222, United States; Ambrose T., Seagate Technology, Pittsburgh, PA 15222, United States; Kaka S., Seagate Technology, Pittsburgh, PA 15222, United States; Batra S., Seagate Technology, Pittsburgh, PA 15222, United States","In this paper, we study the magnetization reversal process of single-domain Stoner-Wohlfarth particles subject to circularly polarized fields and short pulses using analytical and numerical models.We investigate the effect of short unipolar, bipolar field, and circularly polarized field pulses, which are applied perpendicular to the uniaxial magnetocrystalline anisotropy axis, on the magnetization switching dynamics. © 2008 IEEE.","Fast switching; Landau-Lifshitz-Gilbert (LLG) equation; Magnetization reversal","","","","","","","","He L., Doyle W.D., Fujiwara H., High speed coherent switching below the Stoner-Wohlfarth limit, IEEE Trans. Magn., 30, 6 PART 1-2, pp. 4086-4088, (1994); Suess D., Schrefl T., Scholz W., Fidler J., Fast switching of small magnetic particles, J. Magn. Magn. Mater., 242-245, pp. 426-429, (2002); Sun Z.Z., Wang X.R., Theoretical limit of the minimal magnetization switching field and the optimal field pulse for stoner particles, Phys. Rev. Lett., 97, (2006); Kaka S., Russek S., Switching in spin-valve devices in response to subnanosecond longitudinal field pulses, J. Appl. Phys., 87, 9, pp. 6391-6393, (2000); Gerrits Th., Hohlfeld J., Gielkens O., Veenstra K.J., Bal K., Rasing Th., Van Den Berg H.A.M., Magnetization dynamics in NiFe thin films induced by short in-plane magnetic field pulses, J. Appl. Phys., 89, pp. 7648-7650, (2001); Tudosa I., Stamm C., Kashuba A.B., King F., Siegmann H.C., Stoehr J., Ju G., Lu B., Weller D., The ultimate speed of magnetic switching in granular recording media, Nature, 428, pp. 831-833, (2004)","W. Scholz; Seagate Technology, Pittsburgh, PA 15222, United States; email: werner.scholz@seagate.com","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-73849085322" +"Tan S.G.; Jalil M.B.A.; Fujita T.; Liu X.J.","Tan, S.G. (8571745900); Jalil, M.B.A. (7006821429); Fujita, T. (7405809582); Liu, X.J. (8569136800)","8571745900; 7006821429; 7405809582; 8569136800","Spin dynamics under local gauge fields in chiral spin-orbit coupling systems","2011","Annals of Physics","326","2","","207","215","8","28","10.1016/j.aop.2010.11.014","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79151480638&doi=10.1016%2fj.aop.2010.11.014&partnerID=40&md5=773e9d73b65521756e0503a00ab9558a","Data Storage Institute, A and z.ast;STAR Agency for Science Technology and Research, DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore; Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Department of Physics, National University of Singapore, Singapore 117542, 2 Science Drive 3, Singapore","Tan S.G., Data Storage Institute, A and z.ast;STAR Agency for Science Technology and Research, DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore, Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore, Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Fujita T., Data Storage Institute, A and z.ast;STAR Agency for Science Technology and Research, DSI Building, Singapore 117608, 5 Engineering Drive 1, Singapore, Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore, Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Liu X.J., Department of Physics, National University of Singapore, Singapore 117542, 2 Science Drive 3, Singapore","We present a theoretical description of local spin dynamics in magnetic systems with a chiral spin texture and finite spin-orbit coupling (SOC). Spin precession about the relativistic effective magnetic field in a SOC system gives rise to a non-Abelian SU(2) gauge field reminiscent of the Yang-Mills field. In addition, the adiabatic relaxation of electron spin along the local spin yields an U(1). ⊗. U(1) topological gauge (Berry) field. We derive the corresponding equation of motion i.e. modified Landau-Lifshitz-Gilbert (LLG) equation, for the local spin under the influence of these effects. Focusing on the SU(2) gauge, we obtain the spin torque magnitude, and the amplitude and frequency of spin oscillations in this system. Our theoretical estimates indicate significant spin torque and oscillations in systems with large spin-orbit coupling, which may be utilized in technological applications such as current-induced magnetization-switching and tunable microwave oscillators. © 2010 Elsevier Inc.","Berry curvature; Spin torque; Spin transport; Spin-orbit coupling","","","","","","","","Baibich M.N., Et al., Phys. Rev. Lett., 61, (1988); Binasch G., Grunberg P., Saurenbach F., Zinn W., Phys. Rev. B, 39, (1989); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Albert F.J., Emley N.C., Myers E.B., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 89, (2002); Jiang Y., Nozaki T., Abe S., Ochiai T., Hirohata A., Tezuka N., Inomata K., Nat. Mater., 3, (2004); Houssameddine D., Ebels U., Delat B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-Buda L., Cyrille M.-C., Redon O., Dieny B., Nat. Mater., 6, (2007); Slavin A.N., Tiberkevich V.S., Phys. Rev. Lett., 95, (2005); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Tserkovnyak Y., Wong C.H., Phys. Rev. B, 79, (2009); Tatara G., Kohno H., Phys. Rev. Lett., 92, (2004); Bazaliy Y.B., Jones B.A., Zhang S.-C., Phys. Rev. B, 57, (1998); Tatara G., Takayama T., Kohno H., Shibata J., Nakatani Y., Fukuyama H., J. Phys. Soc. Jpn., 75, (2006); Tatara G., J. Phys. Soc. Jpn., 69, (2000); Waintal X., Myers E.B., Brouwer P.W., Ralph D.C., Phys. Rev. B, 62, (2000); Stiles M.D., Zangwill A., J. Appl. Phys., 91, (2002); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Tan S.G., Phys. Rev. B, 77, (2008); Kumar S.B., Tan S.G., Jalil M.B.A., Appl. Phys. Lett., 90, (2007); Moodera J.S., Kinder L.R., Wong T.M., Meservey R., Phys. Rev. Lett., 74, (1995); Lee K.J., Deac A., Redon O., Nozires J.P., Dieny B., Nat. Mater., 3, (2004); Jalil M.B.A., Tan S.G., Phys. Rev. B, 72, (2005); Yakushiji K., Et al., Nat. Mater., 4, (2005); Ernult F., Yakushiji K., Mitani S., Takanashi K., J. Phys.: Condens. Matter, 19, (2007); Tan S.G., Jalil M.B.A., Liu X.-J., Fujita T., Phys. Rev. B, 78, (2008); Shen S.-Q., Phys. Rev. Lett., 95, (2005); Hatano N., Shirasaki R., Nakamura H., Phys. Rev. A, 75, (2007); Bernevig B.A., Zhang S.-C., Phys. Rev. Lett., 96, (2006); Berard A., Mohrbach H., Phys. Lett. A, 352, (2006); Murakami S., New J. Phys., 9, (2007); Yang C.N., Mills R.L., Phys. Rev., 96, (1954); Bernevig B.A., Hughes T.L., Zhang S.-C., Science, 314, (2006); Fang Z., Et al., Science, 302, (2003); Murakami S., Nagaosa N., Zhang S., Science, 301, (2003); Weinberg S., The Quantum Theory of Fields II, (2005); Huang K., Quantum Field Theory: From Operators to Path Integrals, (1998); Bliokh K.Y., Bliokh Y.P., Ann. Phys., 319, (2005); Brown W.F., Phys. Rev., 130, (1963); Tan S.G., Jalil M.B.A., Liew T., Phys. Rev. B, 72, (2005); Mishchenko E.G., Phys. Rev. B, 68, (2003); Glazov M.M., Sherman E.Y., Phys. Rev. B, 71, (2005)","S.G. Tan; Computational Nanoelectronics and Nano-device Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; email: TAN_Seng_Ghee@dsi.a-star.edu.sg","","","","","","","","1096035X","","APNYA","","English","Ann. Phys.","Article","Final","","Scopus","2-s2.0-79151480638" +"Wu J.-H.; Kong L.-B.; Kim Y.K.","Wu, Jun-Hua (55713950600); Kong, Ling-Bing (7201533198); Kim, Young Keun (24502952300)","55713950600; 7201533198; 24502952300","Structural and microwave properties of Fe-based nanopowders via mechanochemical synthesis","2007","Solid State Phenomena","124-126","PART 1","","851","854","3","2","10.4028/3-908451-31-0.851","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-38049183206&doi=10.4028%2f3-908451-31-0.851&partnerID=40&md5=5256e9a468e4b65de2f2b531ae675af2","Research Institute of Engineering and Technology, Korea University, Seoul 136-713, South Korea; Temasek Labs., National University of Singapore, Singapore 119260, Singapore; Department of Materials Science and Engineering, Korea University, Seoul 136-713, South Korea","Wu J.-H., Research Institute of Engineering and Technology, Korea University, Seoul 136-713, South Korea; Kong L.-B., Temasek Labs., National University of Singapore, Singapore 119260, Singapore; Kim Y.K., Department of Materials Science and Engineering, Korea University, Seoul 136-713, South Korea","Structural and microwave properties of Fe-based nanoalloy powders, mechanochemically synthesized with a composition corresponding to Finemet (Fe73.5Si13.5B9Nb3Cu1), were investigated. The nanopowders, dominated by bcc-Fe (Si), consist of nanocrystallites and display high magnetization with low-coercivity. The microwave measurements show that the nanocomposites comprising the nanopowders possess high, broadband magnetic permeability.","Alloy; LLG equation; Mechanochemistry; Microwave; Nanopowder; Permeability","Magnetization; Mechanical permeability; Microwaves; Synthesis (chemical); LLG equation; Mechanochemistry; Nanopowder; Nanostructured materials","","","","","","","Toneguzzo P., Viau G., Acher O., Fievet-Vincent F., Fievet F., Adv. Mater, 10, (1998); Deng L.W., Jiang J.J., Fan S.C., Feng Z.K., Xie W.Y., Zhang X.C., He H.H., J. Magn. Magn. Mater, 264, (2003); Machida K.-I., Liu J.R., Itoh M., IEEE Trans. Magn, 41, (2005); Sanz R., Luna C., Hernandez-Velez M., Vazquez M., Lopez D., Mijangos C., Nanotechnology, 16, (2005); Zhou P.H., Deng L.J., Xie J.L., Liang D.F., Chen L., Zhao X.Q., J. Magn. Magn. Mater, 292, (2005); Zhang D.L., Prog. Mater. Sci, 49, (2004); Suryanarayana C., Prog. Mater. Sci, 46, (2001); Yoshizawa Y., Oguma S., Yamauchi K., J. Appl. Phys, 64, (1988); Yanai T., Yamasaki M., Takahashi K.-I., Nakano M., Yoshizawa Y., Fukunaga H., IEEE Trans.Magn, 40, (2004); Herzer G., IEEE Trans. Magn, 25, (1989); Zhang X.Y., Zhang J.W., Xiao F.R., Liu J.H., Zhang K.Q., Zheng Y.Z., J. Mater. Res, 13, (1998); Hono K., Inoue A., Sakurai T., Appl. Phys. Lett, 58, (1991); Lovas A., Kiss L.F., Balogh I., J. Magn. Magn. Mater, 215-216, (2000); Hono K., Ping D.H., Ohnuma M., Onodera H., Acta Mater, 47, (1999); Ohnuma M., Ping D.H., Abe T., Onodera H., Hono K., Yoshizawa Y., J. Appl. Phys, 93, (2003); Cullity B.D., Stock S.R., Elements of X-ray Diffraction, (2001); Lyasotskii I.V., Dyakonova N.B., Vlasova E.N., Dyakonov D.L., Yazvitskii M.Y., Phys. Stat. Sol. (a), 203, (2006); Nowosielski R., Wysiocki J.J., Wnuk I., Gramatyk P., J. Mater. Proc Tech; van de Riet E., Roozeboom F., J. Appl. Phys, 81, (1997); Wu J.H.; Zhou P.H., Deng L.J., Xie J.L., Liu Y.Q., Emerging Tech.-Nanoelec (IEEE Conf, (2006); Wu J.H., Kong L.B., Deng C.R., Lim S.Y., Chen Y.Z., Int. Symp. Metastable, Mechanically Alloyed and Nanocrystalline Materials, (2004); Vazquez M., Luna C., Morales M.P., Sanz R., Sema C.J., Mijangos C., Physica B: Condensed Matter, 354, (2004); Viau G., Fievet-Vincent F., Fievet F., Toneguzzo P., Ravel F., Acher O., J. Appl. Phys, 81, (1997)","J.-H. Wu; Research Institute of Engineering and Technology, Korea University, Seoul 136-713, South Korea; email: wujh@korea.ac.kr","","Trans Tech Publications Ltd","Chinese MRS; MRS-India; MRS-Japan; MRS-Singapore; MRS-Taiwan","IUMRS International Conference in Asia 2006, IUMRS-ICA 2006","10 September 2006 through 14 September 2006","Jeju","71324","10120394","3908451310; 978-390845131-0","DDBPE","","English","Diffus Def Data Pt B","Conference paper","Final","","Scopus","2-s2.0-38049183206" +"Camley R.E.","Camley, R.E. (7005900299)","7005900299","Chapter 4 Static, Dynamic, and Thermal Properties of Magnetic Multilayers and Nanostructures","2006","Contemporary Concepts of Condensed Matter Science","1","C","","77","114","37","1","10.1016/S1572-0934(05)01004-8","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77957094392&doi=10.1016%2fS1572-0934%2805%2901004-8&partnerID=40&md5=2218023597fa6c5a12bca8560d688a04","","","It is clear that to understand magnetic multilayers and nanostructures both the static configurations and the spin dynamics must be examined. As we have seen, the theoretical methods discussed above produce results which agree remarkably well with the data and allow us to understand the rich physics contained in magnetic multilayers, both in their ground state properties and in their dynamical response to probes. The techniques outlined here give simple methods to obtain complex magnetic structures as a function of magnetic field and temperature. All the parameters that characterize the magnetic material - anisotropy, exchange coupling, magnetization, surface effects, impurities, dipolar interactions, and magnetic structure - play a role in determining the frequency of the allowed spin waves. As a result, measurements of the dynamic properties are very useful in determining the fundamental parameters of magnetic structures. The techniques discussed here have already been applied to a large range of problems. In addition to the study of equilibrium states in nanostructures, there have also been investigations into magnetization reversal in ultra-small objects. Dots [52,53], dot arrays [54], and anti-dot arrays have been examined, and the influence of magnetic pinholes in the spacer layer between ferromagnetic films on the exchange coupling between the films as a function of temperature has been studied [55]. Differences in the dynamics between granular systems and multilayers have been examined [56]. Using the LLG equations, one can also study the nonlinear dynamic behavior of multilayers and other systems [57]. As we have seen in this chapter, magnetic multilayer systems have a rich and varied set of physical properties, many of which have no counterpart in bulk magnetism. Because the importance of interfacial interactions can be controlled by layering pattern or film thicknesses, one can make ""designer materials"" with magnetic phase diagrams and dynamic response subject to design. In addition, surprisingly simple theoretical approaches can be used to make quantitative predictions which relate the phase diagrams and the dynamic response to specific material parameters. © 2006 Elsevier B.V. All rights reserved.","","","","","","","","","Binasch G., Gruenberg P., Saurenbach F., Zinn W., Enhanced magnetoresistance in layered magnetic structures with antiferromagnetic interlayer exchange, Phys. Rev. B, 39, (1989); Baibich M.N., Broto J.M., Fert A., Van Dau N.F., Petroff F., Etienne P., Creuzet P., Friederich A., Chazelas J., Giant magnetoresistance of (001)Fe/(001)Cr magnetic superlattices, Phys. Rev. Lett., 61, (1988); Camley R.E., Barnas J., Theory of giant magnetoresistance effects in magnetic layered structures with antiferromagnetic coupling, Phys. Rev. Lett., 63, (1989); Corciovei A., Costache G., Vamanu D., Solid State Physics, 27, (1972); Majkrzak C.F., Cable J.W., Kwo J., Hong M., McWhan D.B., Yafet Y., Waszczak J.V., Vettier C., Observation of a magnetic antiphase domain structure with long-range order in a synthetic Gd-Y superlattice, Phys. Rev. Lett., 56, (1986); Kwo J., Hong M., Di Salvo F.J., Waszczak J.V., Majkrzak C.F., Modulated magnetic properties in synthetic rare-earth Gd-Y superlattices, Phys. Rev. B, 35, (1987); Camley R.E., Stamps R.L., Magnetic multilayers: Spin configurations, excitations and giant magnetoresistance, J. Phys. Condens. Matter, 5, (1993); Keffer F., Chow H., Dynamics of the antiferromagnetic spin-flop transition, Phys. Rev. Lett., 31, (1973); Mills D.L., A surface spin flop state in a simple antiferromagnet, Phys. Rev. Lett., 20, (1968); Lepage J.G., Camley R.E., Surface phase transitions and spin-wave modes in semi-infinite magnetic superlattices with antiferromagnetic interfacial coupling, Phys. Rev. Lett., 65, (1990); Noertemann F.C., Stamps R.L., Carrico A.S., Camley R.E., Finite-size effects on spin configurations in antiferromagnetically coupled multilayers, Phys. Rev. B, 46, (1992); Carrico A.S., Camley R.E., Stamps R.L., Phase diagram of thin antiferromagnetic films in strong magnetic fields, Phys. Rev. B, 50, (1994); Wang R.W., Mills D.L., Fullerton E.E., Mattson J.E., Bader S.D., Surface spin-flop transition in Fe/Cr(211) superlattices: Experiment and theory, Phys. Rev. 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Coll., 49, (1988); Hahn W., Loewenhaupt M., Huang Y.Y., Felcher G.P., Parkin S.S.P., Experimental determination of the magnetic phase diagram of Gd/Fe multilayers, Phys. Rev. B, 52, (1995); Haskel D., Choi Y., Lee D.R., Lang J.C., Srajer G., Jiang J.S., Bader S.D., Hard X-ray magnetic circular dichroism study of a surface-driven twisted state in Gd/Fe multilayers, J. Appl. Phys., 93, (2003); Siegmann H.C., Mauri D., Scholl D., Kay E., Surface and thin film magnetism with spin polarized electrons, J. Phys. Coll., 49, (1988); Cochran J.F., Light scattering from ultrathin magnetic layers and B layers, Ultrathin Magnetic Structures II, (1994); Hillebrands B., Guntherodt G., Brillouin light scattering in magnetic superlattices, Ultrathin Magnetic Structures II, (1993); Heinrich B., Ferromagnetic resonance in ultrathin film structures, Ultrathin Magnetic Structures II, pp. 195-290, (1994); Bland J.A.C., Johnson A.D., Lauter H.J., Bateson R.D., Blundell S.J., Shackleton C., Penfold J., Spin-polarised neutron reflection studies of epitaxial films, J. Magn. Magn. Mater., 93, (1991); Collins M.F., Magnetic Critical Scattering, (1989); Saunders R.W., Belanger R.M., Motokawa M., Jaccarino V., Far-infrared laser study of magnetic polaritons in FeF2 and Mn impurity mode in FeF2: Mn, Phys. Rev. B, 23, (1981); Remer L., Luthi B., Sauer H., Geick R., Camley R.E., Nonreciprocal optical reflection of the uniaxial antiferromagnet MnF2, Phys. Rev. Lett., 56, (1986); Jensen M.R.F., Parker T.J., Abraha K., Tilley D.R., Experimental observation of magnetic surface polaritons in FeF2 by attenuated total reflection, Phys. Rev. Lett., 75, (1995); Jensen M.R.F., Feiven S.A., Parker T.J., Camley R.E., Experimental determination of magnetic polariton dispersion curves in FeF2, Phys. Rev. B, 55, (1997); Jensen M.R.F., Feiven S.A., Parker T.J., Camley R.E., Experimental observation and interpretation of magnetic polariton modes in FeF2, J. Phys: Condens. Matter, 9, (1997); Camley R.E., Magnetization dynamics in thin films and multilayers, J. Magn. Magn. Mater., 200, (1999); Vohl M., Barnas J., Gruenberg P., Effect of interlayer exchange coupling on spin-wave spectra in magnetic double layers: Theory and experiment, Phys. Rev. B, 39, (1989); Stamps R.L., Spin configurations and spin-wave excitations in exchange-coupled bilayers, Phys. Rev. B, 49, (1994); Rezende S.M., Lucena M.A., deAguiar F.M., Azevedo A., Chesman C., Kabos P., Patton C.E., High-resolution Brillouin light scattering and angle-dependent 9.4-GHz ferromagnetic resonance in MBE-grown Fe/Cr/Fe on GaAs, Phys. Rev. B, 55, (1997); Drovosekov A.B., Kholin D.I., Kolmogorov A.N., Kreines N.M., Mescheriakov V.F., Miliayev M.A., Romashev L.N., Ustinov V.V., The observation of non-homogeneous FMR modes in multilayer Fe/Cr structures, J. Magn. Magn. Mater., 198-199, (1999); Koon N.C., Calculations of exchange bias in thin films with ferromagnetic/antiferromagnetic interfaces, Phys. Rev. Lett., 78, (1997); Schulthess T.C., Butler W., Consequences of spin-flop coupling in exchange biased films, Phys. Rev. Lett., 81, (1998); Camley R.E., Astalos R.J., Probing the ferromagnet/antiferromagnet interface with spin waves, J. Magn. Magn. Mater., 198-199, (1999); Grimsditch M., Camley R., Fullerton E.E., Jiang S., Bader S.D., Sowers C.H., Exchange-spring systems: Coupling of hard and soft ferromagnets as measured by magnetization and Brillouin light scattering, J. Appl. Phys., 85, (1999); Astalos R.J., Camley R.E., Magnetic permeability for exchange-spring magnets: Application to Fe/Sm-Co, Phys. Rev. B, 58, (1998); Novosad V., Grimsditch M., Guslienko K.Yu., Vavassori P., Otani Y., Bader S.D., Spin excitations of magnetic vortices in ferromagnetic nanodots, Phys. Rev. B, 66, (2002); Gerardin O., Gall H.Le., Donahue M.J., Vukadinovic N., Micromagnetic calculation of the high frequency dynamics of nano-size rectangular ferromagnetic stripes, J. Appl. Phys., 89, (2001); Grimsditch M., Leaf G.K., Kaper H.G., Karpeev D.A., Camley R.E., Normal modes of spin excitations in magnetic nanoparticles, Phys. Rev. B, 69, (2004); Buda L.D., Prejbeanu I.L., Ebels U., Ounadjela K., Micromagnetic simulations of magnetisation in circular cobalt dots, Comp. Mater. Sci., 24, pp. 181-185, (2002); Hoellinger R., Killinger A., Krey U., Statics and fast dynamics of nanomagnets with vortex structure, J. Magn. Magn. Mater., 261, pp. 178-189, (2003); Stamps R.L., Camley R.E., Magnetization processes and reorientation transition for small magnetic dots, Phys. Rev. B, 60, pp. 11670-11694, (1999); Fulghum D.B., Camley R.E., Magnetic behavior of antiferromagnetically coupled layers connected by ferromagnetic pinholes, Phys. Rev. B, 52, (1995); Wongsam M.A., Chantrell R.W., Simulations of spin dynamics in cobalt-based magnetic multilayers, Phys. Rev. B, 58, (1998); Rezende S.M., de Aguiar F.M., Nonlinear dynamics in microwave driven coupled magnetic multilayer systems, J. Appl. Phys., 79, (1996)","","","","","","","","","15720934","","","","English","Contemp. Concepts Condens. Matter Sci.","Review","Final","","Scopus","2-s2.0-77957094392" +"Yan P.; Sun Z.Z.; Schliemann J.; Wang X.R.","Yan, P. (57201619980); Sun, Z.Z. (8223689800); Schliemann, J. (7004623714); Wang, X.R. (25947844700)","57201619980; 8223689800; 7004623714; 25947844700","Optimal spin current pattern for fast domain wall propagation in nanowires","2010","EPL","92","2","27004","","","","8","10.1209/0295-5075/92/27004","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-78751641757&doi=10.1209%2f0295-5075%2f92%2f27004&partnerID=40&md5=52c7036f744a397ec4b23bdf906797ff","Physics Department, Hong Kong University of Science and Technology, Hong Kong, Clear Water Bay, Hong Kong; Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany","Yan P., Physics Department, Hong Kong University of Science and Technology, Hong Kong, Clear Water Bay, Hong Kong; Sun Z.Z., Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany; Schliemann J., Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany; Wang X.R., Physics Department, Hong Kong University of Science and Technology, Hong Kong, Clear Water Bay, Hong Kong","One of the important issues in nanomagnetism is to lower the current needed for a technologically useful domain wall (DW) propagation speed. Based on the modified Landau-Lifshitz-Gilbert (LLG) equation with both Slonczewski spin-transfer torque and the field-like torque, we derive an optimal temporally and spatially varying spin current pattern for fast DW propagation along nanowires. Under such conditions, the DW velocity in biaxial wires can be enhanced as much as tens of times higher than that achieved in experiments so far. Moreover, the fast variation of spin polarization can efficiently help DW depinning. Possible experimental realizations are discussed. Copyright © EPLA, 2010.","","","","","","","","","Parkin S.S.P., Hayashi M., Thomas L., Science, 320, (2008); Yamaguchi A., Ono T., Nasu S., Miyake K., Mibu K., Shinjo T., Phys. Rev. Lett., 92, (2004); Klaui M., Jubert P.O., Allenspach R., Bischof A., Bland J.A.C., Faini G., Rudiger U., Vaz C.A.F., Vila L., Vouille C., Phys. Rev. Lett., 95, (2005); Beach G.S.D., Knutson C., Nistor C., Tsoi M., Erskine J.L., Phys. Rev. Lett., 97, (2006); Hayashi M., Thomas L., Rettner C., Moriya R., Bazaliy Y.B., Parkin S.S.P., Phys. Rev. Lett., 98, (2007); Tatara G., Kohno H., Phys. Rev. Lett., 92, (2004); Zhang S., Li Z., Phys. Rev. Lett., 93, (2004); Barnes S.E., Maekawa S., Phys. Rev. Lett., 95, (2005); Hals K.M.D., Nguyen A.K., Brataas A., Phys. Rev. Lett., 102, (2009); Schryer N.L., Walker L.R., J. Appl. Phys., 45, (1974); Malozemoff A.P., Slonczewski J.C., Magnetic Domain Walls in Bubble Materials, (1979); Thiaville A., Nakatani Y., Spin Dynamics in Confined Magnetic Structures, 3, (2006); Wang X.R., Yan P., Lu J., He C., Ann. Phys. (N. Y.), 324, (2009); Wang X.R., Yan P., Lu J., EPL, 86, (2009); Lewis E.R., Petit D., Jausovec A.V., Brien O., Read D.E., Zeng H.T., Cowburn R.P., Phys. Rev. Lett., 102, (2009); Yan M., Kakay A., Gliga S., Hertel R., Phys. Rev. Lett., 104, (2010); Slonczewski J., J. Magn. & Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Yan P., Wang X.R., Phys. Rev. B, 80, (2009); Sun Z.Z., Schliemann J., Phys. Rev. Lett., 104, (2010); Khvalkovskiy A.V., Zvezdin K.A., Gorbunov Y.V., Cros V., Grollier J., Fert A., Zvezdin A.K., Phys. Rev. Lett., 102, (2009); Boone C.T., Katine J.A., Carey M., Childress J.R., Cheng X., Krivorotov I.N., Phys. Rev. Lett., 104, (2010); Heide C., Phys. Rev. Lett., 87, (2001); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Xia K., Kelly P.J., Bauer G.E.W., Brataas A., Turek I., Phys. Rev. B, 65, (2002); Gmitra M., Barnas J., Phys. Rev. Lett., 96, (2006); Zimmler M.A., Zyilmaz O., Chen W., Kent A.D., Sun J.Z., Rooks M.J., Koch R.H., Phys. Rev. B, 70, (2004); Yan P., Wang X.R., Appl. Phys. Lett., 96, (2010); Kruger B., Pfannkuche D., Bolte M., Meier G., Merkt U., Phys. Rev. B, 75, (2007); Bocklage L., Kruger B., Matsuyama T., Bolte M., Merkt U., Pfannkuche D., Meier G., Phys. Rev. Lett., 103, (2009); Doring W., Z. Naturforsch., 3, (1948); Saitoh E., Miyajima H., Yamaoka T., Tatara G., Nature (London), 432, (2004); Klaui M., J. Phys: Condens. Matter., 20, (2008); Tao K., Stepanyuk V.S., Hergert W., Rungger I., Sanvito S., Bruno P., Phys. Rev. Lett., 103, (2009); Delgado F., Palacios J.J., Rossier J.F., Phys. Rev. Lett., 104, (2010); Ziegler M., Ruppelt N., Neel N., Kroger J., Berndt R., Appl. Phys. Lett., 96, (2010); Duine R.A., Phys. Rev. B, 77, (2008)","P. Yan; Physics Department, Hong Kong University of Science and Technology, Hong Kong, Clear Water Bay, Hong Kong; email: phxwan@ust.hk","","","","","","","","12864854","","","","English","EPL","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-78751641757" +"Behin-Aein B.; Salahuddin S.; Datta S.","Behin-Aein, Behtash (26433087000); Salahuddin, Sayeef (8544299000); Datta, Supriyo (57206956172)","26433087000; 8544299000; 57206956172","Switching energy of ferromagnetic logic bits","2009","IEEE Transactions on Nanotechnology","8","4","4799197","505","514","9","61","10.1109/TNANO.2009.2016657","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-67949124578&doi=10.1109%2fTNANO.2009.2016657&partnerID=40&md5=1aca31846a5810da98374e5974e5f97e","School of Electrical and Computer Engineering, National Science Foundation (NSF), Purdue University, West Lafayette, IN 47907, United States; School of Electrical Engineering and Computer Science, University of California (UC) Berkeley, Berkeley, CA 94720, United States","Behin-Aein B., School of Electrical and Computer Engineering, National Science Foundation (NSF), Purdue University, West Lafayette, IN 47907, United States; Salahuddin S., School of Electrical Engineering and Computer Science, University of California (UC) Berkeley, Berkeley, CA 94720, United States; Datta S., School of Electrical and Computer Engineering, National Science Foundation (NSF), Purdue University, West Lafayette, IN 47907, United States","Power dissipation in switching devices is believed to be the single most important roadblock to the continued downscaling of electronic circuits. There is a lot of experimental effort at this time to implement switching circuits based on magnets and it is important to establish power requirements for such circuits and their dependence on various parameters. This paper analyzes switching energy that is dissipated in the switching process of single-domain ferromagnets used as cascadable logic bits. We obtain generic results that can be used for comparison with alternative technologies or guide the design of magnet-based switching circuits. Two central results are established. One is that the switching energy drops significantly if the ramp time of an external pulse exceeds a critical time. This drop occurs more rapidly than what is normally expected of adiabatic switching for a capacitor. The other result is that under the switching scheme that allows for logic operations, the switching energy can be described by a single equation in both fast and slow limits. Furthermore, these generic results are used to discuss the practical consideration such as dissipation versus speed, increasing the switching speed and scaling. It is further explained that nanomagnets can have scaling laws similar to CMOS technology. © 2006 IEEE.","Adiabatic pulse; Cascadable logic; Critical ramp time; Fast pulse; Landau-Lifshitz-Gilbert equation (LLG); Magnetic quantum cellular automata (MQCA); Nanomagnet; Switching energy","Cellular automata; Choppers (circuits); CMOS integrated circuits; Drops; Electric power supplies to apparatus; Electric switchgear; Electron tubes; Ferromagnetic materials; Ferromagnetism; Magnetic logic devices; Magnets; Pattern recognition systems; Translation (languages); Adiabatic pulse; Cascadable logic; Critical ramp time; Fast pulse; Landau-Lifshitz-Gilbert equation (LLG); Magnetic quantum cellular automata (MQCA); Nanomagnet; Switching energy; Switching","","","","","","","Salahuddin S., Datta S., Interacting systems for self correcting low power systems, Appl. Phys. Lett, 90, (2007); Cowburn R.P., Welland M.E., Room temperature magnetic quantum cellular automata, Science, 287, pp. 1466-1468, (2000); Cowburn R.P., Adeyeye A.O., Welland M.E., Controlling magnetic ordering in coupled nanomagnet arrays, New J. Phys, 1, (1999); Imre A., Csaba G., Ji L., Orlove A., Bernstein G.H., Porod W., Majority logic gate for magnetic quantum-dot cellular automata, Science, 311, pp. 205-208, (2006); Ney A., Pampuch C., Koch R., Ploog K.H., Programmable computing with a single magnetoresistive element, Nature, 425, pp. 485-487, (2003); Allwood D.A., Xiong G., Cooke M.D., Faulkner C.C., Atkinson D., Vernier N., Cowburn R.P., Submicrometer ferromagnetic NOT gate and shift register, Science, 296, pp. 2003-2004, (2002); Allwood D.A., Xiong G., Faulkner C.C., Atkinson D., Petit D., Cowburn R.P., Magnetic domain-wall logic, Science, 309, pp. 1688-1692, (2002); Csaba G., Porod W., Csurgay A.I., A computing architecture composed of field-coupled single domain nanomagnets clocked by magnetic field, Int. J. Circ. Theor. Appl, 31, pp. 67-82, (2003); Csaba G., Imre A., Bernstein G.H., Porad W., Metlushko V., Nanocomputing byfield-coupled nanomagnets, IEEE Trans. Nanotech, 1, 4, pp. 209-213, (2002); Csaba G., Lugli P., Porod W., Power dissipation in nanomagnetic logic devices, Proc. 4th IEEE Conf. Nanotechnol, pp. 346-348, (2004); Csaba G., Lugli P., Csurgay A., Porod W., Simulation of power gain and dissipation in field-coupled nanomagnets, J. Comp. Elec, 4, pp. 105-110, (2005); Niemier M., Alam M., Hu X.S., Bernstein G., Porod W., Putney M., DeAngelis J., Clocking structures and power analysis for nanomagnetbased logic devices, Proc. 2007 Int. Symp. Low Power Electron. Design (ISLPED), pp. 26-31; Nikonov D.E., Bourianoff G.I., Gargini P.A., Power dissipation in spintronic devices out of thermodynamic equilibrium, J. Super. Novel. Magn, 19, 6, pp. 497-513, (2006); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn, 40, 6, pp. 3443-3449, (2004); Spin Dynamics in Confined Magnetic Structures I, II, (2001); Bennet C.H., The thermodynamics of computation - a review, Intern. J. Theor. Phys, 21, pp. 905-940, (1982); Likharev K.K., Korotkov A.N., Single-electron parametron: Reversible computation in a discrete-state system, Science, 273, pp. 763-765, (1996); Kummamuru R.K., Orlov A.O., Ramasubramaniam R., Lent C.S., Bernstein G.H., Snider G., Operation of a quantum-dot cellular automata (QCA) shift register and analysis of errors, IEEE Trans. Electron Devices, 50, 9, pp. 1906-1913, (2003); Street R., Woolley J.C., A study of magnetic viscosity, Proc. Phys. Soc., Sec. A, 62, pp. 562-572, (1949); Neel L., Thermoremanent magnetization of fine powders, Rev. Mod. Phys, 25, pp. 293-295, (1953); Brown W.F., Thermal fluctuations of a single-domain particle, Phys. Rev, 130, pp. 1677-1686, (1963); Gaunt P., The frequency constant for thermal activationofaferromagnetic domain wall, J. Appl. Phys, 48, pp. 3470-3474, (1977); Leff H.S., Rex A.F., Maxwell's Demon 2, (2003); Cavin III R.K., Zhirnov V.V., Hutchby J.A., Bourianoff G.I., Energy barriers, demons, and minimum energy operation of electronic devices (plenary paper), Proc. SPIE, 5844, pp. 1-9, (2005); Sun Z.Z., Wang X.R., Fast magnetization switching of Stoner particles: A nonlinear dynamics picture, Phys. Rev. B, 71, (2005); Sun S., Murray C.B., Weller D., Folks L., Moser A., Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices, Science, 287, pp. 1989-1992, (2000); Wu X.W., Liu C., Li L., Jones P., Chantrell R.W., Weller D., Nonmagnetic shell in surfactant-coated FePt nanoparticles, J. Appl. Phys, 95, 11, pp. 6810-6812, (2004); Perumal A., Ko H.S., Shin S.C., Magnetic properties of carbondoped FePt nanogranular films, Appl. Phys. Lett, 83, 16, pp. 3326-3328, (2003); Elkins K., Li D., Poudyal N., Nandwana V., Jin Z., Chen K., Liu J.P., Monodisperse face-centered tetragonal FePt nanoparticles with giant coercivity, J. Phys. D: Appl. Phys, 38, pp. 2306-2309, (2005); Augustine C., Fong X., Behin-Aein B., Roy K., A design methodology and device/circuit/architecture compatible simulation framework for low-power magnetic quantum cellular automata systems, Proc. ASPDAC, pp. 847-852, (2009)","","","","","","","","","1536125X","","","","English","IEEE Trans. Nanotechnol.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-67949124578" +"Sun Z.; Schliemann J.","Sun, Zhouzhou (8223689800); Schliemann, John (7004623714)","8223689800; 7004623714","Optimized field pulse for quasi-1-D magnetic domain wall motion","2011","IEEE Transactions on Magnetics","47","10","6028141","2680","2684","4","0","10.1109/TMAG.2011.2147285","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80053514644&doi=10.1109%2fTMAG.2011.2147285&partnerID=40&md5=2f310c62083841d5ae239fcec4c9568a","Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany","Sun Z., Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany; Schliemann J., Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany","In this paper, we analytically investigated the field-driven domain wall (DW) propagation along magnetic nanowires in the framework of the Landau-Lifshitz-Gilbert (LLG) equation. We proposed a new strategy to speed up DW motion in a uniaxial anisotropy nanowire by using an optimized space-dependent field pulse synchronized with the DW motion. Depending on the small damping parameter, the DW velocity can be increased by two orders of magnitude compared to the standard case of a static uniform field. Moreover, under the optimized field pulse, the change in total magnetic energy in nanowires is proportional to the DW velocity, implying that rapid energy release is essential for fast DW propagation. Besides, for large damping, we also proposed an optimized spatio-temporal pulse which can lead to the DW pinning with a fast angular rotation around the wire axis. © 2011 IEEE.","Magnetic domain wall (DW) motion; magnetic nanowires; optimized magnetic field pulse","Damping; Magnetic domains; Nanowires; Angular rotations; Damping parameters; Landau-Lifshitz-Gilbert equations; Magnetic energies; Magnetic nanowires; Optimized magnetic fields; Orders of magnitude; Uniaxial anisotropy; Domain walls","","","","","Alexander von Humboldt-Stiftung; Deutsche Forschungsgemeinschaft, DFG, (SFB 689)","ACKNOWLEDGMENT Z. Sun would like to thank the Alexander von Humboldt Foundation, Germany, for a grant. This work was supported by Deutsche Forschungsgemeinschaft via SFB 689.","Ono T., Miyajima H., Shigeto K., Mibu K., Hosoito N., Shinjo T., Propagation of a magnetic domain wall in a submicrometer magnetic wire, Science, 284, pp. 468-470, (1999); Atkinson D., Allwood A., Xiong G., Cooke M.D., Faulkner C., Cowburn R.P., Magnetic domain-wall dynamics in a submicrometre ferromagnetic structure, Nature Mater., 2, pp. 85-87, (2003); Beach G.S.D., Nistor C., Knutson C., Tsoi M., Erskine J.L., Dynamics of field-driven domain-wall propagation in ferromagnetic nanowires, Nature Mater., 4, pp. 741-744, (2005); Schryer N.L., Walker L.R., The motion of 180 domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, pp. 5406-5421, (1974); Wang X.R., Yan P., Lu J., High-field domain wall propagation velocity in magnetic nanowires, Europhys. Lett., 86, (2009); Klaui M., Jubert P.-O., Allenspach R., Bischof A., Bland J.A.C., Faini G., Rudiger U., Vaz C.A.F., Vila L., Vouille C., Direct observation of domain-wall configurations transformed by spin currents, Phys. Rev. Lett., 95, (2005); Hayashi M., Thomas L., Rettner C., Moriya R., Bazaliy Y.B., Parkin S.S.P., Current driven domain wall velocities exceeding the spin angular momentum transfer rate in permalloy nanowires, Phys. Rev. Lett., 98, (2007); Zhang S., Li Z., Roles of nonequilibrium conduction electrons on themagnetization dynamics of ferromagnets, Phys. Rev. Lett., 93, (2004); Thiaville A., Nakatani Y., Miltat J., Suzuki Y., Micromagnetic understanding of current-driven domain wall motion in patterned nanowires, Europhys. Lett., 69, pp. 990-996, (2005); Parkin S.S.P., Hayashi M., Thomas L., Magnetic domain-wall racetrack memory, Science, 320, pp. 190-194, (2008); Allwood D.A., Xiong G., Faulkner C.C., Atkinson D., Petit D., Cowburn R.P., Magnetic domain-wall logic, Science, 309, pp. 1688-1692, (2005); Mark S., Durrenfeld P., Pappert K., Ebel L., Brunner K., Gould C., Molenkamp L.W., Fully electrically read-write device out of a ferromagnetic semiconductor, Phys. Rev. Lett., 106, (2011); Yan M., Kakay A., Gliga S., Hertel R., Beating the walker limit with massless domain walls in cylindrical nanowires, Phys. Rev. Lett., 104, (2010); Sun Z.Z., Schliemann J., Fast domain wall propagation under an optimal field pulse in magnetic nanowires, Phys. Rev. Lett., 104, (2010); McMichael R.D., Donahue M.J., Head to head domain wall structures in thin magnetic strips, IEEE Trans. Magn., 33, pp. 4167-4169, (1997); Min H., McMinchael R.D., Donahue M.J., Miltat J., Stiles M.D., Effects of disorder and internal dynamics on vortexwall propagation, Phys. Rev. Lett., 104, (2010); Goussev A., Robbins J.M., Slastikov V., Domain-wall motion in ferromagnetic nanowires driven by arbitrary time-dependent fields: An exact result, Phys. Rev. Lett., 104, (2010); Sobolev V.L., Huang H.L., Chen S.C., Generalized equations for domain wall dynamics, J. Appl. Phys., 75, pp. 5797-5799, (1994); Lu J., Wang X.R., Motion of transverse domain walls in thin magnetic nanostripes under transverse magnetic fields, J. Appl. Phys., 107, (2010); Bryan M.T., Schrefl T., Atkinson D., Allwood D.A., Magnetic domain wall propagation in nanowires under transverse magnetic fields, J. Appl. Phys., 103, (2008); Sun Z.Z., Wang X.R., Fast magnetization switching of Stoner particles: A nonlinear dynamics picture, Phys. Rev. B, 71, (2005); Sun Z.Z., Wang X.R., Strategy to reduce minimal magnetization switching field for Stoner particles, Phys. Rev. B, 73, (2006); Yan P., Sun Z.Z., Schliemann J., Wang X.R., Optimal spin current pattern for fast domain wall propagation in nanowires, Europhys. Lett., 92, (2010)","Z. Sun; Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany; email: phzzsun@gmail.com","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-80053514644" +"Zheng Y.K.; Han G.C.; Liu B.","Zheng, Y.K. (7404838151); Han, G.C. (7202923478); Liu, B. (7005671607)","7404838151; 7202923478; 7005671607","Thermal magnetic noise control in the ultra-high-density read head","2008","Journal of Magnetism and Magnetic Materials","320","22","","2850","2853","3","3","10.1016/j.jmmm.2008.07.042","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-53749097184&doi=10.1016%2fj.jmmm.2008.07.042&partnerID=40&md5=35e7d94a89e24b98fa508c6bb95bc144","Data Storage Institute, Republic of Singapore 117608, DSI Building 5, Engineering Drive I, Singapore","Zheng Y.K., Data Storage Institute, Republic of Singapore 117608, DSI Building 5, Engineering Drive I, Singapore; Han G.C., Data Storage Institute, Republic of Singapore 117608, DSI Building 5, Engineering Drive I, Singapore; Liu B., Data Storage Institute, Republic of Singapore 117608, DSI Building 5, Engineering Drive I, Singapore","In order to reduce the resistance of tunnel magnetoresistive (TMR) read heads, a large stripe height sensor structure was proposed. The thermal magnetic noise, called as mag-noise, in this type of TMR heads was simulated by micromagnetic modeling using the Landau-Lifshitz-Gilbert (LLG) gyro-magnetic equation. It is found that for the same hard bias strength, both the sensitivity and the mag-noise of TMR heads increase as the sensor height increases. The signal-to-noise ratio (SNR) is reduced at large stripe height. The large increase in the demagnetization field resulting from the stripe height increase causes the weakening of the effective bias field, thus increasing the mag-noise significantly. Low mag-noise and high SNR can be obtained by increasing the hard bias strength and reducing the spacer between the hard bias and the free layer. An extended hard bias structure has been proposed to further increase SNR of TMR heads. © 2008.","Extended bias; Large stripe height sensor; Mag-noise; TMR head","Acoustic intensity; Demagnetization; Magnetic materials; Sensor networks; Sensors; Signal to noise ratio; Extended bias; Large stripe height sensor; Mag-noise; TMR head; Magnetic heads","","","","","","","Smith N., Arnett P., Appl. Phys. Lett., 78, (2001); Klaassen K.B., Xing X.Z., van Peppen J.C.L., IEEE Trans. Magn., 41, (2005); Zhou Y.C., Zhu J.G., Kim N., J. Appl. Phys., 93, (2003); Han G.C., Zheng Y.K., Liu Z.Y., Liu B., Mao S.N., J. Appl. Phys., 100, (2006); Smith N., Katine J.A., Childress J.R., Carey M.J., IEEE Trans. Magn., 42, (2006); Heinonen O., Cho H.S., IEEE Trans. Magn., 40, (2004); Zheng Y.K., Han G.C., Li K.B., Guo Z.B., Qiu J.J., Tan S.G., Liu Z.Y., Liu B., Wu Y.H., IEEE Trans. Magn., 42, (2006)","G.C. Han; Data Storage Institute, Republic of Singapore 117608, DSI Building 5, Engineering Drive I, Singapore; email: han_guchang@dsi.a-star.edu.sd","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-53749097184" +"Tilioua M.","Tilioua, M. (6507877823)","6507877823","On the bilinear exchange coupling in ferromagnetic multilayers","2009","Journal of Physics A: Mathematical and Theoretical","42","14","145203","","","","1","10.1088/1751-8113/42/14/145203","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-67650759929&doi=10.1088%2f1751-8113%2f42%2f14%2f145203&partnerID=40&md5=e2a1b2924ece14f3110f045f21923c2a","Université Hassan 1, Faculté Polydisciplinaire de Khouribga, Techniques et Sciences de l'Ingénieur (STSI), 25000 Khouribga, Morocco","Tilioua M., Université Hassan 1, Faculté Polydisciplinaire de Khouribga, Techniques et Sciences de l'Ingénieur (STSI), 25000 Khouribga, Morocco","We investigate a mathematical model describing the bilinear interlayer exchange coupling (IEC) of ferromagnets through spacers. We propose an extension in the case of the Maxwell system of the results obtained in Hamdache K and Tilioua M (2004 SIAM J. Appl. Math. 64 1077-97). The model couples the Landau-Lifshitz-Gilbert (LLG) equations with the Maxwell system. The Hoffmann interfacial boundary condition is considered to take into account bilinear IEC. The behavior of the electromagnetic field in the two cases of a thin and large nonmagnetic spacer is discussed. For example we obtain that the magnetic field in the nonmagnetic spacer vanishes in the case of a thin spacer. However the electric field depends explicitly on the initial data. Various other convergence results are also given. © 2009 IOP Publishing Ltd.","","","","","","","","","Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Alouges F., Soyeur A., On global weak solutions for Landau-lifshitz equations: Existence and non uniqueness, Nonlinear Anal., 18, 11, pp. 1071-1084, (1992); Brown W.F., Micromagnetics, (1963); Hamdache K., Tilioua M., On the zero thickness limit of thin ferromagnetic films with surface anisotropy energy, Math. Models Methods Appl. Sci., 11, 8, pp. 1469-1490, (2001); Hamdache K., Tilioua M., Interlayer exchange coupling for ferromagnets through spacers, SIAM J. Appl. Math., 64, 3, pp. 1077-1097, (2004); Hartmann U., Magnetic Multilayers and Giant Magnetoresistance: Fundamentals and Industrial Applications, (2000); Hoffmann F., Dynamics pinning induced by nickel layers on permalloy films, Phys. Status Solidi, 41, 2, pp. 807-813, (1971); Hoffmann F., Thèse de Doctorat d'Etat, (1971); Landau L., Lifshitz E., On the theory of dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjet., 8, pp. 153-169, (1935); Stiles M.D., Interlayer exchange coupling, Journal of Magnetism and Magnetic Materials, 200, 1, pp. 322-337, (1999); Tilioua M., PhD Thesis, (2003); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Japan. J. Appl. Math, 2, pp. 69-84, (1985)","M. Tilioua; Université Hassan 1, Faculté Polydisciplinaire de Khouribga, Techniques et Sciences de l'Ingénieur (STSI), 25000 Khouribga, Morocco; email: mouhcine.tilioua@gmail.com","","","","","","","","17518121","","","","English","J. Phys. Math. Theor.","Article","Final","","Scopus","2-s2.0-67650759929" +"Oogane M.; Wakitani T.; Yakata S.; Yilgin R.; Ando Y.; Sakuma A.; Miyazaki T.","Oogane, Mikihiko (9733080100); Wakitani, Takeshi (13611477500); Yakata, Satoshi (13612865000); Yilgin, Resul (9244881300); Ando, Yasuo (7401803498); Sakuma, Akimasa (7102719646); Miyazaki, Terunobu (8547213500)","9733080100; 13611477500; 13612865000; 9244881300; 7401803498; 7102719646; 8547213500","Magnetic damping in ferromagnetic thin films","2006","Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers","45","5 A","","3889","3891","2","180","10.1143/JJAP.45.3889","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33646896962&doi=10.1143%2fJJAP.45.3889&partnerID=40&md5=1ce02ae67a4e9b5db7b0d41d0a3d1f67","Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan","Oogane M., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Wakitani T., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Yakata S., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Yilgin R., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Ando Y., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Sakuma A., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; Miyazaki T., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan","We determined the Gilbert damping constants of Fe-Co-. Ni and Co-Fe-B alloys with various compositions and half-metallic Co2MnAl Heusler alloy films prepared by magnetron sputtering. The ferromagnetic resonance (FMR) technique was used to determine the damping constants of the prepared films. The out-of-plane angular dependences of the resonance field (HR) and line width (ΔHpp) of FMR spectra were measured and fitted using the Landau-Lifshitz-Gilbert (LLG) equation. The experimental results fitted well, considering the inhomogeneities of the films in the fitting. The damping constants of the metallic films were much larger than those of bulk ferrimagnetic insulators and were roughly proportional to (g - 2)2, where g is the Lande g factor. We discuss the origin of magnetic damping, considering spin-orbit and s-d interactions. © 2006 The Japan Society of Applied Physics.","Ferromagnetic resonance; Magnetic damping; MRAM; Spin dynamics","Ferromagnetic resonance; Film growth; Insulating materials; Magnetic properties; Magnetron sputtering; Thin films; Magnetic damping; MRAM; Plane angular dependences; Spin dynamics; Damping","","","","","","","Heinrich B., Cochran J.F., Adv. Phys., 42, (1993); Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Frait Z., Fraitova D., Spin Waves and Magnetic Excitations, 2 PART, (1988); Djayaprawira D.D., Tsunekawa K., Nagai M., Maehara H., Yamagata S., Watanabe N., Yuasa S., Suzuki Y., Ando K., Appl. Phys. Lett., 86, (2005); Hayakawa J., Ikeda S., Matsukura F., Takahashi H., Ohno H., Jpn. J. Appl. Phys., 44, (2005); Sakuraba Y., Nakata J., Oogane M., Kubota H., Ando Y., Sakuma A., Miyazaki T., Jpn. J. Appl. Phys., 44, (2005); Mizukami S., Ando Y., Miyazaki T., Jpn. J. Appl. Phys., 40, (2001); Schreiber F., Pflaum J., Frait Z., Muhge Th., Pelzl J., Solid State Commun., 93, (1995); Platow W., Anisimov A.N., Dunifer G.L., Farle M., Baberschke K., Phys. Rev. B, 58, (1988); Kubota H., Nakata J., Oogane M., Ando Y., Sakuma A., Miyazaki T., Jpn. J. Appl. Phys., 43, (2004); Oogane M., Nakata J., Kubota H., Ando Y., Sakuma A., Miyazaki T., Jpn. J. Appl. Phys., 44, (2005); Beuneu F., Monod P., Phys. Rev. B, 18, (1978); Elliott R.J., Phys. Rev., 96, (1954); Kambersky V., Can. J. Phys., 48, (1970); Galanakis I., Phys. Rev. B, 71, (2005); Vittoria C., Lubitz P., Hansen P., Tolksdori W., J. Appl. Phys., 57, (1985); Sakuma A.","M. Oogane; Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Aoba-yama 05, Japan; email: oogane@mlab.apph.tohoku.ac.jp","","","","","","","","13474065","","JAPND","","English","Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap","Article","Final","","Scopus","2-s2.0-33646896962" +"Lakshmanan M.","Lakshmanan, M. (7006704351)","7006704351","The fascinating world of the Landau-Lifshitz-Gilbert equation: An overview","2011","Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences","369","1939","","1280","1300","20","221","10.1098/rsta.2010.0319","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79953207309&doi=10.1098%2frsta.2010.0319&partnerID=40&md5=2f2c264258f0d32a9757f1279eccdd38","Department of Physics, Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirapalli 620 024, India","Lakshmanan M., Department of Physics, Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirapalli 620 024, India","The Landau-Lifshitz-Gilbert (LLG) equation is a fascinating nonlinear evolution equation both from mathematical and physical points of view. It is related to the dynamics of several important physical systems such as ferromagnets, vortex filaments, moving space curves, etc. and has intimate connections with many of the well-known integrable soliton equations, including nonlinear Schrödinger and sine-Gordon equations. It can admit very many dynamical structures including spin waves, elliptic function waves, solitons, dromions, vortices, spatio-temporal patterns, chaos, etc. depending on the physical and spin dimensions and the nature of interactions. An exciting recent development is that the spin torque effect in nanoferromagnets is described by a generalization of the LLG equation that forms a basic dynamical equation in the field of spintronics. This article will briefly review these developments as a tribute to Robin Bullough who was a great admirer of the LLG equation. © 2011 The Royal Society.","Chaos and patterns; Integrability; LLG equation; Spin systems","Chaotic systems; Multilayers; Solitons; Spin dynamics; Vortex flow; Chaos and patterns; Dromions; Dynamical equation; Dynamical structure; Elliptic functions; Ferromagnets; Integrability; Landau-Lifshitz-Gilbert equations; LLG equation; Nonlinear evolution equation; Physical systems; Sine-Gordon equation; Soliton equation; Space curve; Spatiotemporal patterns; Spin systems; Spin-torque effect; Spintronics; Vortex filament; Nonlinear equations","","","","","","","Hillebrands B., Ounadjela K., Spin Dynamics in Confined Magnetic Structures, Vols I and II, (2002); Landau L.D., Lifshitz L.M., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Physik. Zeits. Sowjetunion, 8, pp. 153-169, (1935); Gilbert T.L., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Mattis D.C., Theory of Magnetism I: Statics and Dynamics, (1988); Stiles M.D., Miltat J., Spin-transfer torque and dynamics, Topics in Applied Physics, 101, pp. 225-308, (2006); Bertotti G., Mayergoyz I., Serpico C., Nonlinear Magnetization Dynamics in Nanosystems, (2009); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, pp. 9353-9358, (1996); Slonczewski J.C., Current-driven excitation of magnetic multilayers, J. Magn. Magn. Mater., 159, (1996); Lakshmanan M., Nakumara K., Landau-Lifshitz equation of ferromagnetism: Exact treatment of the Gilbert damping, Phys. Rev. Lett., 53, pp. 2497-2499, (1984); Murugesh S., Lakshmanan M., Spin-transfer torque induced reversal in magnetic domains, Chaos Solitons Fractals, 41, pp. 2773-2781, (2009); Yang Z., Zhang S., Li Y.C., Chaotic dynamics of spin-valve oscillators, Physical Review Letters, 99, 13, (2007); Murugesh S., Lakshmanan M., Bifurcations and chaos in spin-valve pillars in a periodic applied magnetic field, Chaos, 19, (2009); Grollier J., Cros V., Fert A., Synchronization of spin-transfer oscillators driven by stimulated microwave currents, Physical Review B - Condensed Matter and Materials Physics, 73, 6, pp. 1-4, (2006); Bazaliy Y.B., Jones B.A., Zhang S.C., Current induced magnetization switching in small domains of differentanisotropies, Phys. Rev. B, 69, (2004); Lakshmanan M., Saxena A., Dynamic and static excitations of a classical discrete anisotropic Heisenberg ferromagnetic spin chain, Physica D, 237, pp. 885-897, (2008); Roberts J.A.G., Thompson C.J., Dynamics of the classical Heisenberg spin chain, J. Phys. A, 21, pp. 1769-1780, (1988); Granovskii Y.I., Zhedanov A.S., Integrability of a classical XY chain, JETP Lett., 44, pp. 304-307, (1986); Veselov A.P., Integration of the stationary problem for a classical spin chain, Theor. Math. Phys., 71, pp. 446-449, (1987); Ishimori Y., An integrable classical spin chain, J. Phys. Soc. Jpn., 51, pp. 3417-3418, (1982); Quispel G.R.W., Roberts J.A.G., Thompson C.J., Integrable mappings and soliton equations, Phys. Lett. A, 126, pp. 419-421, (1988); Zolotaryuk Y., Flach S., Fleurov V., Discrete breathers in classical spin lattices, Phys. Rev. B, 63, (2001); Sheka D.D., Gaididei Y., Mertens F.G., Current induced switching of vortex polarity in magnetic nanodisks, Applied Physics Letters, 91, 8, (2007); Lakshmanan M., Ruijgrok T.W., Thompson C.J., On the dynamics of continuum spin system, Physica A, 84, pp. 577-590, (1976); Lakshmanan M., Continuum spin system as an exactly solvable dynamical system, Phys. Lett. A, 61, pp. 53-54, (1977); Zakharov V.E., Takhtajan L.A., Equivalence of the nonlinear Schrödinger equation and the equation of a Heisenberg ferromagnet, Theor. Math. Phys., 38, pp. 17-20, (1979); Takhtajan L.A., Integration of the continuous Heisenberg spin chain through the inverse scattering method, Phys. Lett. A, 64, pp. 235-238, (1977); Daniel M., Lakshmanan M., Perturbation of solitons in the classical continuum isotropic Heisenberg spin system, Physica A, 120, pp. 125-152, (1983); Lakshmanan M., Bullough R.K., Geometry of generalized nonlinear Schrödinger and Heisenberg ferromagnetic spin equations with linearly x-dependent coefficients, Phys. Lett. A, 80, pp. 287-292, (1980); Daniel M., Porsezian K., Lakshmanan M., On the integrability of the inhomogeneous spherically symmetric Heisenberg ferromagnet in arbitrary dimensions, J. Math. Phys., 35, pp. 6498-6510, (1994); Mikhailov A.V., Yaremchuk A.I., Axially symmetrical solutions of the two-dimensional Heisenberg model, JETP Lett., 36, pp. 78-81, (1982); Porsezian K., Lakshmanan M., On the dynamics of the radially symmetric Heisenberg spin chain, J. Math. Phys., 32, pp. 2923-2928, (1991); Nakamura K., Sasada T., Gauge equivalence between one-dimensional Heisenberg ferromagnets with single-site anisotropy and nonlinear Schrodinger equations, J. Phys. C, 15, (1982); Sklyanin E.K., On the Complete Integrability of the Landau-Lifschitz Equation, (1979); Daniel M., Kruskal M.D., Lakshmanan M., Nakamura K., Singularity strucutre analysis of the continuum Heisenberg spin chain with anisotropy and transverse field: Nonintegrability and chaos, J. Math. Phys., 33, pp. 771-776, (1992); Porsezian K., Daniel M., Lakshmanan M., On the integrability of the one dimensional classical continuum isotropic biquadratic Heisenberg spin chain, J. Math. Phys., 33, pp. 1607-1616, (1992); Porsezian K., Tamizhmani K.M., Lakshmanan M., Geometrical equivalence of a deformed Heisenberg spin equation and the generalized nonlinear Schrödinger equation, Phys. Lett. A, 124, pp. 159-160, (1987); Daniel M., Kavitha L., Magnetization reversal through soliton flipping in a biquadratic ferromagnet with varying exchange interactions, Phys. Rev. B, 66, (2002); Mikeska H.J., Steiner M., Solitary excitations in one dimensional magnets, Adv. Phys., 40, pp. 191-356, (1991); Lakshmanan M., Daniel M., On the evolution of higher dimensional Heisenberg ferromagnetic spin systems, Physica A, 107, pp. 533-552, (1981); Senthil Kumar C., Lakshmanan M., Grammaticos B., Ramani A., Nonintegrability of (2 + 1)-dimensional continuum isotropic Heisenberg spin system: Painlevé analysis, Physics Letters, Section A: General, Atomic and Solid State Physics, 356, 4-5, pp. 339-345, (2006); Belavin A.A., Polyakov A.M., Metastable states of two-dimensional isotropic ferromagnets, JETP Lett., 22, pp. 245-247, (1975); Guo B., Ding S., Landau-Lifshitz Equations, (2008); Ishimori Y., Multi-vortex solutions of a two-dimensional nonlinear wave equation, Prog. Theor. Phys., 72, pp. 33-37, (1984); Lakshmanan M., Myrzakulov R., Vijayalakshmi S., Danlybaeva A.K., Motion of curves and surfaces and nonlinear evolution equations in (2+1) dimensions, Journal of Mathematical Physics, 39, 7, pp. 3765-3771, (1998); Konopelchenko B.G., Matkarimov B.T., Inverse spectral transform for the Ishimori equation: I. Initial value problem, J. Math. Phys., 31, pp. 2737-2746, (1989); Sulem C., Sulem P.L., Nonlinear Schrödinger Equation, (1999); Kosaka C., Nakamura K., Murugesh S., Lakshmanan M., Equatorial and related non-equilibrium states in magnetization dynamics of ferromagnets: Generalization of Suhl's spin-wave instabilities, Physica D: Nonlinear Phenomena, 203, 3-4, pp. 233-248, (2005)","M. Lakshmanan; Department of Physics, Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirapalli 620 024, India; email: lakshman@cnld.bdu.ac.in","","Royal Society","","","","","","1364503X","","","","English","Philos. Trans. R. Soc. A Math. Phys. Eng. Sci.","Review","Final","All Open Access; Green Open Access","Scopus","2-s2.0-79953207309" +"Tamion A.; Raufast C.; Bonet E.; Dupuis V.; Fournier T.; Crozes T.; Bernstein E.; Wernsdorfer W.","Tamion, A. (9740880600); Raufast, C. (14521434600); Bonet, E. (6701573768); Dupuis, V. (7006146119); Fournier, T. (56247832500); Crozes, T. (26639265900); Bernstein, E. (7103262371); Wernsdorfer, W. (7102465752)","9740880600; 14521434600; 6701573768; 7006146119; 56247832500; 26639265900; 7103262371; 7102465752","Magnetization reversal of a single cobalt cluster using a RF field pulse","2010","Journal of Magnetism and Magnetic Materials","322","9-12","","1315","1318","3","15","10.1016/j.jmmm.2009.04.013","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77949290795&doi=10.1016%2fj.jmmm.2009.04.013&partnerID=40&md5=9da888507f451ad53df9e5805f778969","Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; Institut Néel, CNRS, 38042 Grenoble, 25 Avenue Des Martyrs, France","Tamion A., Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; Raufast C., Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; Bonet E., Institut Néel, CNRS, 38042 Grenoble, 25 Avenue Des Martyrs, France; Dupuis V., Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; Fournier T., Institut Néel, CNRS, 38042 Grenoble, 25 Avenue Des Martyrs, France; Crozes T., Institut Néel, CNRS, 38042 Grenoble, 25 Avenue Des Martyrs, France; Bernstein E., Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; Wernsdorfer W., Institut Néel, CNRS, 38042 Grenoble, 25 Avenue Des Martyrs, France","Technological improvements require the understanding of dynamical magnetization reversal processes at the nanosecond time scales. In this paper, we present the first magnetization reversal measurements performed on a single cobalt cluster (counting only a thousand of spins), using the micro-superconducting quantum interference device (SQUID) technique by applying a constant magnetic field combined with a radio-frequency (RF) field pulse. First of all, we present the different technical steps necessary to detect the magnetic reversals at low temperature (T=35 mK) of a well-defined nanoparticle prepared by low energy clusters beam deposition (LECBD). We previously showed that the three-dimensional (3D)-switching Stoner-Wohlfarth astroid represents the magnetic anisotropy of the nanoparticle. Then, an improved device coupled with a gold stripe line, allow us to reverse such macrospin, using a RF pulse. A qualitative understanding of the magnetization reversal by non-linear resonance has been obtained with the Landau-Lifschitz-Gilbert (LLG) equation. © 2009 Elsevier B.V. All rights reserved.","Cluster; Dynamic; Nano-magnetism","Chemical modification; Cobalt; Cobalt compounds; Gold deposits; Magnetic anisotropy; Magnetic devices; Magnetic fields; Nanomagnetics; Nanoparticles; Radiofrequency spectroscopy; SQUIDs; Superconducting magnets; Three dimensional; Beam deposition; Cluster; Cluster dynamics; Cobalt clusters; Constant magnetic fields; Field pulse; Gold stripes; Low energy clusters; Low temperatures; Magnetic reversal; Magnetization reversal process; Nonlinear resonance; Radio frequencies; RF fields; RF pulse; Stoner-Wohlfarth astroid; Superconducting quantum interference device; Technological improvements; Three-dimensional (3D); Time-scales; Magnetization reversal","","","","","","","Mornet S., Vasseur S., Grasset F., Dugnet E., J. Mater. Chem., 14, (2004); Bansmann J., Baker S.H., Binns C., Blackman J.A., Bucher J.-P., Dorantes-Davila J., Dupuis V., Favre L., Kechrakos D., Kleibert A., Meiwes-Broer K.-H., Pastor G.M., Perez A., Toulemonde O., Trohidou K.N., Tuaillon J., Xie Y., Surf. Sci. Rep., 56, (2005); Thirion C., Wernsdorfer W., Mailly D., Nat. Mater., 2, (2003); Alayan R., Arnaud L., Bourgey A., Broyer M., Cottancin E., Huntzinger J.R., Lerme J., Vialle J.L., Pellarin M., Guiraud G., Rev. Sci. Instrum., 75, (2004); Dupuis V., Jamet M., Tuaillon-Combes J., Favre L., Stanescu S., Treilleux M., Bernstein E., Melinon P., Perez A., Rev. Recent Res. Dev. Magn. Magn. Mater., 1, (2003); Raufast C., (2007); Rohart S., Raufast C., Favre L., Bernstein E., Bonet-Orozco E., Dupuis V., Phys. Rev. B, 74, (2006); Tournus F., Tamion A., Blanc N., Hannour A., Bardotti L., Prevel B., Ohresser P., Bonet E., Epicier T., Dupuis V., Et al., Phys. Rev. B, 77, (2008); Jamet M., Wernsdorfer W., Thirion C., Mailly D., Dupuis V., Melinon P., Perez A., Phys. Rev. Lett., 86, (2001); Jamet M., Wernsdorfer W., Thirion C., Dupuis V., Melinon P., Perez A., Phys. Rev. B, 69, (2004)","A. Tamion; Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon 1, 69622 Villeurbanne, France; email: alexandre.tamion@lpmcn.univ-lyon1.fr","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-77949290795" +"Tanaka T.; Matsuzaki J.; Kurisu H.; Yamamoto S.","Tanaka, T. (55727221200); Matsuzaki, J. (24773566200); Kurisu, H. (7004397400); Yamamoto, S. (7408532790)","55727221200; 24773566200; 7004397400; 7408532790","Magnetization behavior of hard/soft-magnetic composite pillar","2008","Journal of Magnetism and Magnetic Materials","320","22","","3100","3103","3","8","10.1016/j.jmmm.2008.08.021","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-53749093971&doi=10.1016%2fj.jmmm.2008.08.021&partnerID=40&md5=59db07217f9be53937fee5879a9b6543","Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan","Tanaka T., Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan; Matsuzaki J., Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan; Kurisu H., Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan; Yamamoto S., Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan","Hard/soft-magnetic composite pillar array medium is proposed for ultra-high-density recording media. Magnetization reversal process for a single hard/soft-magnetic composite pillar in the medium is calculated using the Landau-Lifshitz-Gilbert equation. Magnetization reversal of the soft-magnetic unit helps the magnetization reversal for the hard-magnetic unit, and the effective coercivity for the hard-magnetic unit is greatly reduced. Thereby saturation recording to the high-Ku-hard-magnetic material used for perpendicular magnetic recording will be realizable. © 2008 Elsevier B.V. All rights reserved.","Exchange interaction; Hard- and soft-magnetic composite pillar; LLG equation; Magnetization reversal","Magnetic devices; Magnetic materials; Magnetism; Magnetization; Magnets; Coercivity; Exchange interaction; Hard- and soft-magnetic composite pillar; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic composites; Magnetization behavior; Magnetization reversal processes; Saturation recording; Ultra-high; Magnetization reversal","","","","","","","White R.L., New R.M.H., Pease R.F.W., IEEE. Trans. Magn., 33, (1997); Hughes G.F., IEEE Trans. Magn., 36, (2000); Kawai S., Ueda R., J. Electrochem. Soc., 122, (1975); Shiraki M., Wakui Y., Tokushima T., Tsuya N., IEEE Trans. Magn., MAG-21, (1985); Rahman M.T., Lai C.H., Vokoun D., Shams N.N., IEEE Trans. Magn., 43, (2007); Oshima H., Kikuchi H., Nakao H., Kamimura T., Morikawa T., Matsumoto K., Yuan J., Ishio S., Nishio K., Masuda H., Itoh K., IEEE Trans. Magn., 43, (2007); Gapin A.I., Ye X.R., Chen L.H., Hong D., Jin S., IEEE Trans. Magn., 43, (2007); Chou S.Y., Proc. IEEE, 85, (1997); Masuda H., Nagae M., Morikawa T., Nishio K., Jpn. J. Appl. Phys., 45, (2006); Dobin A.Y., Richter H.J., Appl. Phys. Lett., 89, (2006); Kapoor M., Shen X., Victora R.H., J. Appl. Phys., 99, (2006); Honda N., Yamakawa K., Ouchi K., IEEE Trans. Magn., 43, (2007)","T. Tanaka; Graduate School of Science and Engineering, Yamaguchi University, Ube, 755-8611, 2-16-1 Tokiwadai, Japan; email: t-tanaka@yamaguchi-u.ac.jp","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-53749093971" +"Sun C.-Y.; Wang Z.-C.","Sun, Chun-Yang (36640735800); Wang, Zheng-Chuan (7410043260)","36640735800; 7410043260","Out-of-plane torque influence on magnetization switching and susceptibility in magnetic multilayers","2010","Chinese Physics Letters","27","7","077501","","","","9","10.1088/0256-307X/27/7/077501","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-78649386768&doi=10.1088%2f0256-307X%2f27%2f7%2f077501&partnerID=40&md5=66ee6b05c4c5c10971e6b603eafb2823","College of Physical Sciences, Graduate University of Chinese, Academy of Sciences, Beijing 100049, PO Box 4588, China","Sun C.-Y., College of Physical Sciences, Graduate University of Chinese, Academy of Sciences, Beijing 100049, PO Box 4588, China; Wang Z.-C., College of Physical Sciences, Graduate University of Chinese, Academy of Sciences, Beijing 100049, PO Box 4588, China","Based on both the spin diffusion equation and the Landau-Lifshitz-Gilbert (LLG) equation, we demonstrate the influence of out-of-plane spin torque on magnetization switching and susceptibility in a magnetic multilayer system. The variation of spin accumulation and local magnetization with respect to time are studied in the magnetization reversal induced by spin torque. We also research the susceptibility subject to a microwave magnetic field, which is compared with the results obtained without out-of-plane torque. © 2010 Chinese Physical Society and IOP Publishing Ltd.","","Magnetic multilayers; Torque; Diffusion equations; Landau-Lifshitz-Gilbert equations; Local magnetization; Magnetic multilayer systems; Magnetization switching; Out-of-plane; Out-of-plane torques; Spin torque; Spin-accumulations; Spin-diffusion; Magnetization reversal","","","","","","","Koh G.H., Et al., J. Magn. Magn. Mater., 272, (2004); Houssamddine D., Ebels U., Delaet B., Rodmacq B., Firastrau I., Ponthenier F., Brunet M., Thirion C., Michel J.-P., Prejbeanu-buda L., Cyrille M.-C., Redon O., Dieny B, Nature Mater., 6, (2007); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Huai Y., Albert F., Nguyen P., Pakala M., Valet T., Appl. Phys. Lett., 84, (2004); Fuchs G.D., Emley N.C., Krivorotov I.N., Braganca P.M., Ryan E.M., Kiselev S.I., Sankey J.C., Ralph D.C., Buhrman R.A., Katine J.A., Appl. Phys. Lett., 85, (2004); Tserkovnyak Y., Bartaas A., Bauer G.E.W., Halperin B.I., Rev. Mod. Phys., 77, (2005); Heinrich B., Tserkovnyak Y., Woltersdorf G., Brataas A., Urban R., Bauer G.E.W., Phys. Rev. Lett., 90, (2003); Tsoi M., Jansen A.G.M., Bass J., Chiang W.C., Seck M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, (1998); Tsoi M., Jansen A.G.M., Bass J., Chiang W.C., Tsoi V., Wyder P., Nature, 406, (2000); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Edwards D.M., Federici F., Mathon J., Umerski A., Phys. Rev. B, 71, (2005); Tulapurkar A.A., Suzuki Y., Fukushima A., Kubota H., Maehara H., Tsunekawa K., Djayaprawira D.D., Watanabe N., Yuasa S., Nature, 438, (2005); Petit S., Baraduc C., Thirion C., Ebels U., Liu Y., Li M., Wang P., Dieny B, Phys. Rev. Lett., 98, (2007); Zhang S., Shpiro A., Levy P.M., Phys. Rev. B, 67, (2003); Li F.S., Wen F.S., Zhou D., Qiao L., Zuo W.L., Chin. Phys. Lett., 25, (2008); Wang Z.H., Habermeier H.U., Cristiani G., Sun J.R., Shen B.G., Chin. Phys. Lett., 25, (2008)","Z.-C. Wang; College of Physical Sciences, Graduate University of Chinese, Academy of Sciences, Beijing 100049, PO Box 4588, China; email: wangzc@gucas.ac.cn","","IOP Publishing Ltd","","","","","","0256307X","","","","English","Chin. Phys. Lett.","Article","Final","","Scopus","2-s2.0-78649386768" +"Long H.H.; Ong E.T.; Liu T.; Li H.L.; Liu Z.J.; Li E.P.; Wu H.Y.; Adeyeye A.O.","Long, H.H. (56109395200); Ong, E.T. (7102729139); Liu, T. (55599460300); Li, H.L. (55707649900); Liu, Z.J. (13204247700); Li, E.P. (7201410151); Wu, H.Y. (55707373400); Adeyeye, A.O. (7004047544)","56109395200; 7102729139; 55599460300; 55707649900; 13204247700; 7201410151; 55707373400; 7004047544","Micromagnetic simulations of magnetic nanowires with constrictions by FIB","2006","Journal of Magnetism and Magnetic Materials","303","2 SPEC. ISS.","","e299","e303","4","2","10.1016/j.jmmm.2006.01.120","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33646257338&doi=10.1016%2fj.jmmm.2006.01.120&partnerID=40&md5=b894764c44b1db1b7492db0cc3af6e8f","Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore; Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore; Institute of High Performance Computing, Singapore, 117528, Science Park II, Singapore","Long H.H., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore; Ong E.T., Institute of High Performance Computing, Singapore, 117528, Science Park II, Singapore; Liu T., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore; Li H.L., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore; Liu Z.J., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore; Li E.P., Institute of High Performance Computing, Singapore, 117528, Science Park II, Singapore; Wu H.Y., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore; Adeyeye A.O., Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, 4 Engineering Drive 3, Singapore","Magnetic structures and magnetization processes of individual Ni nanowires with constrictions are investigated by means of micromagnetic modeling. The physical problem is modeled with the Landau-Lifshitz-Gilbert (LLG) equation, and the fast Fourier transform on multipoles (FFTM) method is employed to speed up the calculation of the demagnetization field. It is demonstrated that the FFTM algorithm is efficient and accurate for studying magnetization transition configuration in nanowire. The new approach is then used to study the switching phenomenon of the nanowire. And the simulation results show that the switching field increases a little with presence of constriction. The investigation of the magnetization processes illustrates the edge domain forms near constriction region for nanowire with diameter=30 nm and vortex domain for 200 nm case. © 2006 Elsevier B.V. All rights reserved.","Fast Fourier transform on multipoles method (FFTM); Hybrid FEM/BEM; Magnetic nanowire; Micromagnetic model","Computer simulation; Demagnetization; Fast Fourier transforms; Magnetic domains; Magnetic field effects; Magnetization; Nanostructured materials; Fast Fourier transform on multipoles method (FFTM); Hybrid FEM/BEM; Magnetic nanowires; Micromagnetic models; Micromagnetic simulations; Magnetic materials","","","","","","","Zhang Z.-Y., Xiong S.-J., Phys. Rev. B, 67, (2003); Tanase M., Silvitch D.M., Chien C.L., Reich D.H., J. Appl. Phys., 93, (2003); Vila L., Et al., IEEE Trans. Magn., 38, (2002); Ong E.T., Lim K.M., Lee K.H., Lee H.P., J. Comput. Phys., 192, (2003); Gilbert T.L., Phys. Rev., 100, (1955); Byrne G.D., Hindmarsh A.C., Int. J. High Perf. Comput. Appl., 13, (1999); Seberino C., Bertram H.N., IEEE Trans. Magn., 37, (2001); Koehler T.R., Phys. B., 233, (1997); Hertel R., Kirschner J., Phys. B, 343, (2004); Aharoni A., J. Appl. Phys., 30, (1959)","H.H. Long; Data Storage Institute, Singapore, 117608, DSI Building, 5 Engineering Drive 1, Singapore; email: g0202811@nus.edu.sg","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-33646257338" +"Nakahata Y.; Todaka T.; Enokizono M.","Nakahata, Yasushi (16029172400); Todaka, Takashi (7006715391); Enokizono, Masato (7102846085)","16029172400; 7006715391; 7102846085","Magnetization process simulation of Nd-Fe-B magnets","2010","Przeglad Elektrotechniczny","86","5","","178","180","2","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77951792790&partnerID=40&md5=38bc03cb7925e5b741453aa22ee4cac5","Faculty of Engineering, Oita University, 870-1192 Oita, 700 Dannoharu, Japan","Nakahata Y., Faculty of Engineering, Oita University, 870-1192 Oita, 700 Dannoharu, Japan; Todaka T., Faculty of Engineering, Oita University, 870-1192 Oita, 700 Dannoharu, Japan; Enokizono M., Faculty of Engineering, Oita University, 870-1192 Oita, 700 Dannoharu, Japan","This paper presents results obtained from a numerical simulation of the magnetization of Nd-Fe-B magnets. In the initial magnetization process, we have used the three-dimensional Variable Magnetization and Stoner-Wohlfarth (VMSW) method. In the residual magnetization process, we have used the concept of the micromagnetics. The initial magnetization curves of Nd-Fe-B magnets measured with a magnetizer were used in the initial magnetization process simulation. The calculated results were compared with the measured results to verify the accuracy of the numerical method.","LLG equation; Magnetization process simulation; Nd-Fe-B magnet; VMSW method","","","","","","","","Nakahata Y., Todaka T., Enokizono M., Development of three-dimensional VMSW method, J. Magn. Magn. Mater, 310, pp. 2644-2646; Nakahata Y., Todaka T., Enokizono M., Evaluation of remnant magnetization distribution of rare-earth permanent magnet by using three-dimensional VMSW method, Journal of the Magnetics Society of Japan, 32, pp. 269-274, (2008); Nakahata Y., Todaka T., Enokizono M., Magnetization process simulation of anisotropic permanent magnets by using the three-dimensional VMSW method, IEEE Transactions on Magnetics, 44, pp. 858-861, (2008); Brown Jr. W.F., Micromagnetics, (1978); Nakatani Y., Uesaka Y., Hayashi H., Direct solution of the landau-lifshitz-gilbert equation for micromagnetics, Japanese Journal of Applied Physics, 20, pp. 2485-2507, (1989)","Y. Nakahata; Faculty of Engineering, Oita University, 870-1192 Oita, 700 Dannoharu, Japan; email: y.nakahata@oita-mag.jp","","","","","","","","00332097","","","","English","Prz. Elektrotech.","Conference paper","Final","","Scopus","2-s2.0-77951792790" +"Romeo A.; Finocchio G.; Carpentieri M.; Torres L.; Consolo G.; Azzerboni B.","Romeo, A. (58957583700); Finocchio, G. (55902853000); Carpentieri, M. (8590004000); Torres, L. (56926909600); Consolo, G. (8506731900); Azzerboni, B. (57188761517)","58957583700; 55902853000; 8590004000; 56926909600; 8506731900; 57188761517","A numerical solution of the magnetization reversal modeling in a permalloy thin film using fifth order Runge-Kutta method with adaptive step size control","2008","Physica B: Condensed Matter","403","2-3","","464","468","4","62","10.1016/j.physb.2007.08.076","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-37349103369&doi=10.1016%2fj.physb.2007.08.076&partnerID=40&md5=39eeb6ca92518ef0d5bbac785a3ea67d","Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Departamento de Fisica Aplicada, Universidad de Salamanca, 37008 Salamanca, Plaza de la Merced s/n, Spain","Romeo A., Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Finocchio G., Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Carpentieri M., Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Torres L., Departamento de Fisica Aplicada, Universidad de Salamanca, 37008 Salamanca, Plaza de la Merced s/n, Spain; Consolo G., Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; Azzerboni B., Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy","The Landau-Lifshitz-Gilbert (LLG) equation is the fundamental equation to describe magnetization dynamics in microscale and nanoscale magnetic systems. In this paper we present a brief overview of a time-domain numerical method related to the fifth order Runge-Kutta formula, which has been applied to the solution of the LLG equation successfully. We discuss advantages of the method, describing the results of a numerical experiment based on the standard problem #4. The results are in good agreement with the ones present in literature. By including thermal effects in our framework, our simulations show magnetization dynamics slightly dependent on the spatial discretization. © 2007 Elsevier B.V. All rights reserved.","Magnetization reversal; Micromagnetic model; Standard problem#4","Adaptive control systems; Computer simulation; Magnetization reversal; Mathematical models; Numerical methods; Runge Kutta methods; Micromagnetic models; Nanoscale magnetic systems; Numerical solutions; Permalloy thin films; Magnetic films","","","","","","","Gilbert T.L., Phys. Rev., 100, (1955); Krishnaprasad P.S., Tan X., Physica B, 306, (2001); Lewis D., Nigam N., J. Comput. Appl. Math., 151, (2003); Liu C.S., Z. Angew. Math. Phys., 55, (2004); William H., Et al., Numerical Recipes in C++. The Art of Scientific Computing. second ed, pp. 714-718, (2002); Cash J.R., Karp A.H., ACM Trans. Math. Software, 16, (1990); Brown Jr. W.F., Phys. Rev., 130, (1963); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1996)","A. Romeo; Dipartimento di Fisica della Materia e Tecnologie Fisiche Avanzate, University of Messina, 98166 Messina, Salita Sperone 31, Italy; email: romeo.nino@tiscali.it","","","","","","","","09214526","","PHYBE","","English","Phys B Condens Matter","Article","Final","","Scopus","2-s2.0-37349103369" +"Cheng X.Z.; Jalil M.B.A.; Lee H.K.; Okabe Y.","Cheng, X.Z. (10539190400); Jalil, M.B.A. (7006821429); Lee, Hwee Kuan (12544939000); Okabe, Yutaka (7102069994)","10539190400; 7006821429; 12544939000; 7102069994","Mapping the Monte Carlo scheme to langevin dynamics: A fokker-planck approach","2006","Physical Review Letters","96","6","067208","","","","50","10.1103/PhysRevLett.96.067208","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33144479177&doi=10.1103%2fPhysRevLett.96.067208&partnerID=40&md5=306b658a7feba3f773aaf7a7ab0a66c3","Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, 1-1 Minami-Osawa, Japan; Data Storage Institute, DSI Building, 117608, Singapore, 5 Engineering Drive 1, Singapore","Cheng X.Z., Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore, 4 Engineering Drive 3, Singapore; Lee H.K., Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, 1-1 Minami-Osawa, Japan, Data Storage Institute, DSI Building, 117608, Singapore, 5 Engineering Drive 1, Singapore; Okabe Y., Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, 1-1 Minami-Osawa, Japan","We propose a general method of using the Fokker-Planck equation (FPE) to link the Monte Carlo (MC) and the Langevin micromagnetic schemes. We derive the drift and diffusion FPE terms corresponding to the MC method and show that it is analytically equivalent to the stochastic Landau-Lifshitz-Gilbert (LLG) equation of Langevin-based micromagnetics. Subsequent results such as the time-quantification factor for the Metropolis MC method can be rigorously derived from this mapping equivalence. The validity of the mapping is shown by the close numerical convergence between the MC method and the LLG equation for the case of a single magnetic particle as well as interacting arrays of particles. We also find that our Metropolis MC method is accurate for a large range of damping factors α, unlike previous time-quantified MC methods which break down at low α, where precessional motion dominates. © 2006 The American Physical Society.","","Diffusion; Magnetism; Monte Carlo methods; Random processes; Fokker-Planck equation (FPE); Langevin dynamics; Langevin-based micromagnetics; Magnetic materials","","","","","","","Landau D.P., Binder K., A Guide to Monte Carlo Simulations in Statistical Physics, (2000); Jaeckel P., Monte Carlo Methods in Finance, (2002); Stauffer D., Comput. Sci. Eng., 5, (2003); Fidler J., Schrefl T., J. Phys. D, 33, (2000); Neel L., Ann. Geophys., 5, (1949); Kanai Y., Charap S.H., IEEE Trans. Magn., 27, (1991); Brown W.F., Phys. Rev., 130, (1963); Coffey W.T., Crothers D.S.F., Dormann J.L., Kalmykov Y.P., Kennedy E.C., Wernsdorfer W., Phys. Rev. Lett., 80, (1998); Novotny M.A., Phys. Rev. Lett., 75, (1995); Kolesik M., Novotny M.A., Rikvold P.A., Phys. Rev. Lett., 80, (1998); Lee H.K., Okabe Y., Cheng X.Z., Jalil M.B.A., Comput. Phys. Commun., 168, (2005); Nowak U., Chantrell R.W., Kennedy E.C., Phys. Rev. Lett., 84, (2000); Cheng X.Z., Jalil M.B.A., Lee H.K., Okabe Y., Phys. Rev. B, 72, (2005); Chubykalo O., Nowak U., Smirnov-Rueda R., Wongsam M.A., Chantrell R.W., Gonzalez J.M., Phys. Rev. B, 67, (2003); Reif F., Fundamentals of Statistical and Thermal Physics, (1967); Kikuchi K., Yoshida M., Maekawa T., Watanabe H., Chem. Phys. Lett., 185, (1991); Risken H., The Fokker-Planck Equation, (1967); Coffey W.T., Kalmykov Y.P., Waldron J.T., The Langevin Equation with Applications in Physics, Chemistry and Electrical Engineering, (1996); Cheng X.Z., Jalil M.B.A., Lee H.K., Okabe Y., J. Appl. Phys.; Hinzke D., Nowak U., Phys. Rev. B, 61, (2000)","","","American Physical Society","","","","","","00319007","","PRLTA","","English","Phys Rev Lett","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-33144479177" +"Tilioua M.","Tilioua, Mouhcine (6507877823)","6507877823","Current-induced magnetization dynamics. Global existence of weak solutions","2011","Journal of Mathematical Analysis and Applications","373","2","","635","642","7","18","10.1016/j.jmaa.2010.08.024","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-77956617351&doi=10.1016%2fj.jmaa.2010.08.024&partnerID=40&md5=69404828b396dbe279db009e4c018f54","Hassan I University, Polydisciplinary Faculty of Khouribga, 25000 Khouribga, P.O. Box 145, Morocco","Tilioua M., Hassan I University, Polydisciplinary Faculty of Khouribga, 25000 Khouribga, P.O. Box 145, Morocco","We consider a model of current-induced magnetization dynamics described by the Landau-Lifshitz-Gilbert (LLG) equations of the magnetization, in which an additional current dependent term is added. Two methods, namely Faedo-Galerkin/Penalty (FGP) method and hyperbolic regularization method are used to show the existence of finite energy global weak solutions. © 2010 Elsevier Inc.","Current-induced magnetization dynamics; Ferromagnets; Global existence","","","","","","","","Alouges F., Jaisson P., Convergence of a finite element discretization for the Landau-Lifshitz equations in micromagnetism, Math. Models Methods Appl. Sci., 16, pp. 299-316, (2006); Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and non uniqueness, Nonlinear Anal., 18, pp. 1071-1084, (1992); Bartels S., Ko J., Prohl A., Numerical approximation of an explicit approximation scheme for the Landau-Lifshitz-Gilbert equation, Math. Comp., 77, pp. 773-788, (2008); Bartels S., Prohl A., Convergence of an implicit finite element method for the Landau-Lifshitz-Gilbert equation, SIAM J. Numer. Anal., 44, pp. 1405-1419, (2006); Berger L., Emission of spin waves by a magnetic multilayer traversed by a current, Phys. Rev. B, 54, (1996); Bertsch M., Podio-Guidugli P., Valente V., On the dynamics of deformable ferromagnets. I. Global weak solutions for soft ferromagnets at rest, Ann. Mat. Pura Appl. (4), 179, pp. 331-360, (2001); Carbou G., Fabrie P., Time average in micromagnetism, J. Differential Equations, 147, pp. 383-409, (1998); Evans L.C., Weak Convergences Methods for Nonlinear Partial Differential Equations, (1990); Hamdache K., (2002); Hamdache K., Hamroun D., Ferromagnets with biquadratic exchange coupling energy. Global existence of weak solutions, Math. Methods Appl. Sci., 28, 12, pp. 1403-1421, (2005); Hamdache K., Hamroun D., Tilioua M., On a model of magnetization switching by spin polarized current, Japan J. Indust. Appl. Math., 23, pp. 105-125, (2006); Kohno H., Tatara G., Shibata J., Suzuki Y., Microscopic calculation of spin torques and forces, J. Magn. Magn. Mater., 310, pp. 2020-2022, (2006); Kruzik M., Prohl A., Recent developments in the modeling, analysis, and numerics of ferromagnetism, SIAM Rev., 48, pp. 439-483, (2006); Lions J.L., Quelques Méthodes de Résolution des Problèmes aux Limites Non Linéaires, (1969); Podio-Guidugli P., Valente V., Existence of global-in-time weak solutions to a modified Gilbert equation, Nonlinear Anal., 47, pp. 147-158, (2001); Roubicek T., Tomassetti G., Zanini C., The Gilbert equation with dry-friction type damping, J. Math. Anal. Appl., 355, 2, pp. 453-468, (2009); Slonczewski J.C., Current-driven excitation of magnetic multilayer, J. Magn. Magn. Mater., 159, (1996); Tartar L., Topics in Nonlinear Analysis, (1978); Taylor M., Partial Differential Equations, vols. I-III, (1996); Visintin A., On the Landau-Lifshitz equation for ferromagnetism, Japan J. Appl. Math., 2, pp. 69-84, (1985)","M. Tilioua; Hassan I University, Polydisciplinary Faculty of Khouribga, 25000 Khouribga, P.O. Box 145, Morocco; email: mouhcine.tilioua@gmail.com","","","","","","","","10960813","","","","English","J. Math. Anal. Appl.","Article","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-77956617351" +"Sarsby R.W.","Sarsby, Robert W. (57207629879)","57207629879","Use of 'Limited Life Geotextiles' (LLGs) for basal reinforcement of embankments built on soft clay","2007","Geotextiles and Geomembranes","25","4-5","","302","310","8","92","10.1016/j.geotexmem.2007.02.010","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34547452856&doi=10.1016%2fj.geotexmem.2007.02.010&partnerID=40&md5=b6a10c0ea2bcf2983c1ffda0c7b01445","Civil Engineering Section, SEBE, Wolverhampton University, Wolverhampton, WV1 1SB, Wulfruna Street, United Kingdom","Sarsby R.W., Civil Engineering Section, SEBE, Wolverhampton University, Wolverhampton, WV1 1SB, Wulfruna Street, United Kingdom","Polymeric technical fabrics have long working lives and are sometimes used in practical situations where a geosynthetic is only needed to be fully functional for a relatively short period of time, e.g. a separator layer beneath a temporary access road. This article concerns the use of 'Limited Life Geotextiles' (LLGs), i.e. high specification geotextiles, which are designed on the basis of having a limited working life, as basal reinforcement for an embankment built on soft clay. A method is given for defining the allowable progressive loss of tensile strength of the foregoing basal LLG as a result of improvement of the shear strength of the foundation soil due to consolidation. It is shown that the derived relation between required reinforcement strength and consolidation time (the Time-Strength-Envelope) can be represented by a simple exponential equation. Vegetable fibres are natural candidates for use in the manufacture of LLGs since they are a renewable resource and their degradation with time is accounted for in the design of the LLG. Combinations of vegetable fibres growing in tropical regions which are capable of satisfying the Time-Strength-Envelopes for several embankment slopes are presented. © 2007 Elsevier Ltd. All rights reserved.","Embankment; Geotextiles; Reinforcement; Soft soil","Consolidation; Fabric; Geotextiles; Plant Fibers; Reinforcement; Shear Strength; Tensile Strength; Consolidation; Embankments; Fabrics; Natural fibers; Reinforcement; Shear strength; Tensile strength; clay liner; geosynthetics; geotextile; mathematical analysis; shear property; strength; technical textile; tensile property; embankment; geotextile; shear strength; soft clay; soil reinforcement; tensile strength; Basal reinforcement; Limited Life Geotextiles; Polymeric technical fabrics; Simple exponential equation; Geotextiles","","","","","","","Al Hattamleh O., Muhunthan B., Numerical procedures for deformation calculations in the reinforced soil walls, Geotextiles and Geomembranes, 24, 1, pp. 52-57, (2006); Bathurst R.J., Allen T.M., Walters D.L., Reinforcement loads in geosynthetic walls and the case for a new working stress design method, Geotextiles and Geomembranes, 23, 4, pp. 287-322, (2005); Beckman W.K., Mills W.H., Cotton fabric reinforced roads, Engineering News Records, 115, 14, pp. 453-455, (1957); Bergado T.B., Long P.V., Murthy B.R.S., A case study of geotexile-reinforced embankment on soft ground, Geotextiles and Geomembranes, 20, pp. 343-365, (2002); Bisanda E.T.N., Anselm M.P., Properties of sisal-CNSL composite, Journal of Material Science, (1992); Chand N., Santhayanarayana K.G., Tiwary R.K., Rohatgi P.K., Mechanical characteristics of Sun Hemp fibres, Indian Journal of Textiles Research, (1986); Chand N., Tiwary R.K., Rohatgi P.K., Resources structure properties of natural cellulosic fibres-an annotated bibliography, Journal of Material Science, (1988); Hinchberger S.D., Rowe R.K., Geosynthetic reinforced embankments on soft clay foundations: predicting reinforcement strains at failure, Geotextiles and Geomembranes, 21, pp. 151-175, (2003); Hufenus R., Rueegger R., Banjac R., Mayor P., Springman S.M., Bronnimann R., Full-scale field tests on geosynthetic reinforced unpaved roads on soft subgrade, Geotextiles and Geomembranes, 24, 1, pp. 21-37, (2006); Indraratna B., Khabbaz H., Puswewala A., Bandara W.A.A.W., Effects of tsunami on coastal ground conditions and appropriate measures for rail track rehabilitation, Proceedings of the International Symposium on Tsunami Reconstruction with Geosynthetics, pp. 51-71, (2005); Kazimierowicz-Frankowska K., A case study of a geosynthetic reinforced wall with wrap-around facing, Geotextiles and Geomembranes, 23, 1, pp. 107-115, (2005); Mandal J.N., Geojute, International Geotextile Society News, 5, 3, (1989); Murherjee P.S., Satyanarayana K.G., Structure and properties of some vegetables fibres-Part 1: Sisal fibre, Journal of Material Science, (1984); Nouri H., Fakher A., Jones C.J.F.P., Development of horizontal slice method for seismic stability analysis of reinforced slopes and walls, Geotextiles and Geomembranes, 24, 2, pp. 175-187, (2006); Park T., Tan S.A., Enhanced performance of reinforced soil walls by the inclusion of short fiber, Geotextiles and Geomembranes, 23, 4, pp. 348-361, (2005); Rowe R.K., Li A.A., Reinforced embankments over soft foundations under undrained and partially drained conditions, Geotextiles and Geomembranes, 17, pp. 129-146, (1999); Skinner G.D., Rowe R.K., Design and behaviour of a geosynthetic reinforced retaining wall and bridge abutment on a yielding foundation, Geotextiles and Geomembranes, 23, 3, pp. 235-260, (2005); Varuso R.J., Grieshaber J.B., Nataral M.S., Geosynthetic reinforced levee test section on soft normally consolidated clays, Geotextiles and Geomembranes, 23, pp. 362-383, (2005)","R.W. Sarsby; Civil Engineering Section, SEBE, Wolverhampton University, Wolverhampton, WV1 1SB, Wulfruna Street, United Kingdom; email: R.Sarsby@wlv.ac.uk","","","","","","","","02661144","","","","English","Geotext. Geomembr.","Article","Final","","Scopus","2-s2.0-34547452856" +"Beatrice C.; Fiorillo F.; Landgraf F.J.; Lazaro-Colan V.; Janasi S.; Leicht J.","Beatrice, C. (7004523868); Fiorillo, F. (7006013405); Landgraf, F.J. (8676324800); Lazaro-Colan, V. (24338508000); Janasi, S. (7801631755); Leicht, J. (6603206965)","7004523868; 7006013405; 8676324800; 24338508000; 7801631755; 6603206965","Magnetic loss, permeability dispersion, and role of eddy currents in Mn-Zn sintered ferrites","2008","Journal of Magnetism and Magnetic Materials","320","20","","e865","e868","3","9","10.1016/j.jmmm.2008.04.121","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-47649116518&doi=10.1016%2fj.jmmm.2008.04.121&partnerID=40&md5=e4793911c9db03c01dd89a6f8d29702b","Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy; Universidade de São Paulo, Brazil; Instituto de Pesquisas Tecnologicas, São Paulo, Brazil","Beatrice C., Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy; Fiorillo F., Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy; Landgraf F.J., Universidade de São Paulo, Brazil; Lazaro-Colan V., Universidade de São Paulo, Brazil; Janasi S., Instituto de Pesquisas Tecnologicas, São Paulo, Brazil; Leicht J., Instituto de Pesquisas Tecnologicas, São Paulo, Brazil","Magnetic energy losses and permeability have been investigated in laboratory prepared and commercial Mn-Zn sintered ferrites from quasi-static conditions up to 10 MHz. The mechanisms leading to energy dissipation, either due to domain wall displacements or magnetization rotations, have been quantitatively assessed and their respective roles have been clarified. Domain wall processes dissipate energy by pure relaxation effects, while rotations display resonant absorption of energy over a broad range of frequencies. Their specific contributions to the permeability and its frequency dispersion are thus identified and separately evaluated. It is shown that eddy currents are always too weak to appreciably contribute to the losses over the whole investigated frequency range and that rotations are the dominant magnetization and loss producing mechanisms on approaching the MHz range, as predicted by the Landau-Lifshitz-Gilbert equation with distributed anisotropy fields. © 2008 Elsevier B.V. All rights reserved.","Landau-Lifshitz-Gilbert equation; Magnetic loss; Permeability dispersion; Soft ferrite","Absorption; Capillarity; Clarification; Crystallography; Dispersion (waves); Eddy currents; Electron energy loss spectroscopy; Energy dissipation; Energy dissipators; Ferrite; Ferromagnetism; Fluids; Gyrators; Liquids; Magnetic domains; Magnetism; Magnetization; Magnets; Manganese; Manganese compounds; Mechanisms; Rotation; Sintering; Solids; Walls (structural partitions); Zinc; anisotropy fields; Elsevier (CO); frequency dispersions; frequency ranging; Landau Lifshitz Gilbert (LLG) equations; Magnetic energies; Magnetic loss; Magnetization rotations; Quasi-static conditions; relaxation effects; Resonant absorption; Magnetic leakage","","","","","","","Stoppels D., J. Magn. Magn. Mater., 160, (1996); Sakaki Y., Yosida M., Sato T., IEEE Trans. Magn., 29, (1993); Saotome H., Sakaki Y., IEEE Trans. Magn., 33, (1997); van der Zaag P.J., J. Magn. Magn. Mater., 196-197, (1999); Fiorillo F., Beatrice C., Bottauscio O., Manzin A., Chiampi M., Appl. Phys. Lett., 89, (2006); Beatrice C., Fiorillo F., IEEE Trans. Magn., 42, (2006); Smit J., Wijn H.P.J., Ferrites, (1959); Bottauscio O., Chiampi M., Manzin A., J. Magn. Magn. Mater., 304, (2006); Bottauscio O., Manzin A., Chiado Piat V., Codegone M., Chiampi M., J. Appl. Phys., 100, (2006); Bertotti G., Hysteresis in Magnetism, (1998); Suhl H., IEEE Trans. Magn., 34, (1998); Visser E.G., J. Magn. Magn. Mater., 42, (1984); Bertotti G., IEEE Trans. Magn., 24, (1988)","F. Fiorillo; Istituto Nazionale di Ricerca Metrologica (INRIM), Torino, Italy; email: f.fiorillo@inrim.it","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-47649116518" +"Kanai Y.; Saiki M.; Hirasawa K.; Tsukamomo T.; Yoshida K.","Kanai, Yasushi (56530175700); Saiki, Masahiko (15064617700); Hirasawa, Kazunori (23972981000); Tsukamomo, Toshio (24328950800); Yoshida, Kazuetsu (23017498800)","56530175700; 15064617700; 23972981000; 24328950800; 23017498800","Landau-Lifshitz-Gilbert micromagnetic analysis of single-pole-type write head for perpendicular magnetic recording using full-FFT program on PC cluster system","2008","IEEE Transactions on Magnetics","44","6","4526909","1602","1605","3","14","10.1109/TMAG.2007.916254","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-44149117754&doi=10.1109%2fTMAG.2007.916254&partnerID=40&md5=9567e9d9ae62e1169e826f3384c0ee1a","Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Department of Information and Communications Engineering, Kogakuin University, Tokyo 163-8677, Japan","Kanai Y., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Saiki M., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Hirasawa K., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Tsukamomo T., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Yoshida K., Department of Information and Communications Engineering, Kogakuin University, Tokyo 163-8677, Japan","A Landau-Lifshitz-Gilbert (LLG) micromagnetic analysis using a parallelized program on a PC cluster is investigated. In the analysis, the whole magnetic material is treated micromagnetically using the LLG equation. The fast Fourier transform (FFT) algorithm is incorporated in the head region in addition to the medium region to derive the demagnetization field and the program is parallelized using the message passing interface (MPI). The PC cluster system with 8 CPU has achieved a calculation speed 4800 times faster than our original program on a single 64-bit processor system. Quasi-static field distributions for a single-pole type (SPT) are derived and the accuracy is validated by comparison with the finite-element method (FEM). Finally, dynamic responses are derived for various head structures and materials. © 2008 IEEE.","LLG equation; Micromagnetic simulation; Parallel computing; PC cluster system; Perpendicular magnetic recording; Single-pole-type head","Cluster analysis; Fast Fourier transforms; Finite element method; Parallel processing systems; LLG equation; Micromagnetic simulation; PC cluster system; Magnetic recording","","","","","Japan Society for the Promotion of Science, KAKEN, (18,560,352); Strategic Research Council, SRC","This work was supported in part by a Grant in Aid for the Japan Society for the Promotion of Science (#18,560,352) and Storage Research Consortium (SRC), Japan. The authors acknowledge the members of Storage Research Consortium, Japan and Dr. O. G. Heinonen of Seagate Technology for their helpful discussion. The authors also would like to acknowledge use of LLG micromagnetic software from Central Research Laboratory, Hitachi, Limited and use of JMAG-Studio from JRI Solutions, Ltd.","TDK Announced 437 Gb/in Discrete Track Disk, (2006); Heinonen O., Bozeman S.P., FEM and micromagnetic modeling of perpendicular writers, J. Appl. Phys., 99, 8, (2006); Scholz W., Batra S., Micromagnetic modeling of head field rise time for high data-rate recording, IEEE Trans. Magn., 41, 2, pp. 702-706, (2005); Schrefl T., Schabes M.E., Suess D., Ertl O., Kirschner M., Dorfbauer F., Hrkac G., Fidler J., Partitioning of the perpendicular write field into head and sul contributions, IEEE Trans. Magn., 41, 10, pp. 3064-3066, (2005); Takano K., Micromagnetic-FEM models of a perpendicular writer and reader, IEEE Trans. Magn., 41, 2, pp. 696-701, (2005); Kaya A., Benakli M., Mallary M.L., Bain J.A., A micromagnetic study of the effect of spatial variations in damping in perpendicular recording heads, IEEE Trans. Magn., 42, 10, pp. 2428-2430, (2006); Yoshida K., Suzuki A., Yanagihara H., Calculations of magnetization configurations of SPT head using micromagnetic model, J. Magn. Magn. Mater., 287, pp. 83-88, (2005); Kanai Y., Saiki M., Yoshida K., Micromagnetic simulations of perpendicular single-pole-type head for various pole tip structures, IEEE Trans. Magn., 43, 4, pp. 1665-1668, (2007); Yuan S.W., Bertram H.N., Fast adaptive algorithms for micromagnetics, IEEE Trans. Magn., 28, 5, pp. 2031-2036, (1992); Hayashi N., Saito K., Nakatani Y., Calculation of demagnetizaing field distribution based on Fast Fourier transform of convolution, Jpn. J. Appl. Phys., 35, 12 A AND PART 1, pp. 6065-6073, (1996); Commercial Software. JRI Solutions Ltd.; Press W.H., Teukolsky S.A., Vetterling W.T., Flannery B.P., Numerical recipes in fortran 77, The Art of Scientific Computing, pp. 533-535, (1992); Heinonen O.G., Computational applied magnetics, Boulder 2003 Summer School: Frontiers in Magnetism, (2003)","Y. Kanai; Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; email: kanai@iee.niit.ac.jp","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-44149117754" +"Wang C.; Xia K.","Wang, C. (56600274500); Xia, K. (7101891170)","56600274500; 7101891170","Ballistic current induced effective force on magnetic domain wall","2009","Nano-Micro Letters","1","1","","34","39","5","0","10.5101/nml.v1i1.p34-39","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84861854467&doi=10.5101%2fnml.v1i1.p34-39&partnerID=40&md5=2bb0a3dc6af2e6ca1b305ca4cd9c7cdd","Department of Physics, Beijing Normal University, Beijing 100875, China","Wang C., Department of Physics, Beijing Normal University, Beijing 100875, China; Xia K., Department of Physics, Beijing Normal University, Beijing 100875, China","The collective dynamics of magnetic domain wall under electric current is studied in the form of spin transfer torque (STT). The out-of-plane STT induced effective force is obtained based on the Landau-Lifshitz-Gilbert (LLG) equation including microscopic STT terms. The relation between microscopic calculations and collective description of the domain wall motion is established. With our numerical calculations based on tight binding free electron model, we find that the non adiabatic out-of-plane torque components have considerable non-local properties. It turns out that the calculated effective forces decay significantly with increasing domain wall widths.","First principle study; Magnetic domain; Spin transfer torque; Spintronics","","","","","","National Natural Science Foundation of China, NSFC, (60825405); National Natural Science Foundation of China, NSFC; Ministry of Science and Technology of the People's Republic of China, MOST, (2006CB933000); Ministry of Science and Technology of the People's Republic of China, MOST","The work is supported by NSF of China (Grant No.60825405) and MOST of China (2006CB933000). We are grateful to Shuai Wang for useful discussions and his codes that we used for calculating spin transfer torques.","Wolf S.A., Awschalom D.D., Buhrman R.A., Daughton J.M., von Molnar S., Science, 294, (2001); Zutic I., Fabian J., Das S.S., Rev. Mod. Phys, 76, (2004); Berger P., Rev. B, 54, (1996); Slonczewski J., Magn J., Magn. Mater, 159, (1996); Beach G.S.D., Knutson C., Nistor C., Tsoi M., Erskine J.L., Phys. Rev. Lett, 97, (2006); Tsoi M., Nature Phys, 4, (2008); Sankey J.C., Braganca P.M., Garcia A.G.F., Krivorotov I.N., Buhrman R.A., Ralph D.C., Phys. Rev. Lett, 96, (2006); Stuart S., Parkin P., Science, 320, (2008); Shibata J., Tarara G., Kohno H., Phys. Rev. Lett, 94, (2005); Tatara G., Kohno H., Shibata J., Phys. Rep, 468, (2008); Li Z., Zhang S., Phys. Rev. Lett, 93, (2004); Zhang S., Li Z., Phys. Rev. Lett, 92, (2004); Xiao J., Zangwill A., Stiles M.D., Phys. Rev. B, 73, (2006); Turek I., Drchal V., Kudrnovsky J., Sob M., Weinberger P., Electronic Structure of Disordered Alloys: Surface Sand Interfaces, (1997); Andersen O.K., Jepsen O., Glotzel D., Highlights In Condensed Matter Theory, (1985); Wang S., Xu Y., Xia K., Phys. Rev. B, 77, (2008); Schryer N.L., Walker L.R., J. Appl. Phys, 45, (1974); Wang X.R., Yan P., Lu J., He C., Ann. Phys, 324, (2009)","K. Xia; Department of Physics, Beijing Normal University, Beijing 100875, China; email: kexia@bnu.edu.cn","","Open Access House of Science and Technology","","","","","","23116706","","","","English","Nano-Micro Lett.","Article","Final","All Open Access; Gold Open Access","Scopus","2-s2.0-84861854467" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, Giorgio (7005370974); Mayergoyz, Isaak D. (35495971500); Serpico, Claudio (23013514800)","7005370974; 35495971500; 23013514800","Nonlinear Magnetization Dynamics: Magnetization Modes and Spin Waves under Rotating Fields","2006","The Science of Hysteresis","2-3","","","567","642","75","3","10.1016/B978-012480874-4/50018-X","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-64149130410&doi=10.1016%2fB978-012480874-4%2f50018-X&partnerID=40&md5=58e78625ce3693086fcb05336f15882b","Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, Torino, 10135, Italy; Electrical and Computer Engineering Department and UMIACS, University of Maryland, College Park, 20742, MD, United States; Dipartimento di Ingegneria Elettrica, Universitá degli Studi di Napoli 'Federico II', via Claudio 21, Napoli, 80125, Italy","Bertotti G., Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, Torino, 10135, Italy; Mayergoyz I.D., Electrical and Computer Engineering Department and UMIACS, University of Maryland, College Park, 20742, MD, United States; Serpico C., Dipartimento di Ingegneria Elettrica, Universitá degli Studi di Napoli 'Federico II', via Claudio 21, Napoli, 80125, Italy","This chapter discusses the problem of the existence of spatially uniform magnetization modes under far-from-equilibrium conditions. When magnetization dynamics is spatially uniform, a system governed by the Landau-Lifshitz-Gilbert (LLG) equation is reduced to a nonlinear dynamical system evolving on the surface of the unit sphere and a number of remarkable conclusions can be drawn from this fact by means of topological arguments. The chapter investigates small-amplitude non-uniform deviations from large uniform motions. This study leads to far-from-equilibrium generalizations of the notions of magneto-static mode and of spin wave. The chapter emphasizes on the analysis of generalized spin waves. Itdiscusses the progressive alteration of the spin wave spectrum and the associated dispersion relation when the external field excitation becomes increasingly strong. The results presented in this chapter concern the periodic magnetization response to time-harmonic excitations that eventually sets in after all transients have died out. The transient response is the feature of main interest when the aim is to investigate the switching phenomena. © 2006 Elsevier Ltd. All rights reserved.","","","","","","","","","Bertotti G., Hysteresis in Magnetism, (1998); Gurevich G., Melkov A., Magnetization Oscillations and Waves, (1996); Brown F., Magnetostatic Principles in Ferromagnetism, (1962); Brown F., Micromagnetics, (1963); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Morrish H., The Physical Principles of Magnetism, (2001); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Physik. Zeits. Sowjetunion, 8, pp. 153-169, (1935); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Collected Papers of L. D. Landau, pp. 101-114, (1965); Callen H., A ferromagnetic dynamical equation, J. Phys. Chem. Solids, 4, pp. 256-270, (1958); Suhl H., Theory of the magnetic damping constant, IEEE Trans. Magn., 34, pp. 1834-1838, (1998); Podio-Guidugli L., On dissipation mechanisms in micromagnetics, Eur. Phys. J. B, 19, pp. 417-424, (2001); L.Gilbert T., Phys. Rev., 100, (1955); L.Gilbert T., A phenomenological theory of damping in ferromagnetic materials, IEEE Trans. Magn., 40, pp. 3443-3449, (2004); Mallinson J.C., On damped gyromagnetic precession, IEEE Trans. Magn., 23, pp. 2003-2004, (1987); Silva T.J., Lee C., Crawford T., Rogers C., Inductive measurement of ultrafast magnetization dynamics in thin-film Permalloy, J. Appl. Phys., 85, pp. 7849-7862, (1999); Nibarger J., Lopusnik R., Silva T., Damping as a function of pulsed field amplitude and bias field in thin film Permalloy, Appl. Phys. Lett., 82, pp. 2112-2114, (2003); Bertotti G., Magni A., Mayergoyz I., Serpico C., Landau-Lifshitz magnetization dynamics and eddy currents in metallic thin films, J. Appl. Phys., 91, pp. 7559-7561, (2002); Kittel C., Excitation of spin waves in a ferromagnet by a uniform rf field, Phys. Rev., 110, pp. 1295-1297, (1958); Hubert A., Schaefer R., Magnetic Domains, (1998); Fidler J., Schrefl T., Micromagnetic modeling - the current state of the art, J. Phys. D: Appl. Phys., 33, pp. R135-R156, (2000); Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Walker L., Magnetostatic modes in ferromagnetic resonance, Phys. Rev., 105, pp. 390-399, (1957); Walker L., Resonant modes of ferromagnetic spheroids, J. Appl. Phys., 29, pp. 318-323, (1958); Suhl H., The nonlinear behavior of ferrites at high microwave signal levels, Proc. IRE, 44, pp. 1270-1284, (1956); Suhl H., The theory of ferromagnetic resonance at high signal powers, J. Phys. Chem. Solids, 1, pp. 209-227, (1957); Herring C., Kittel C., On the theory of spin waves in ferromagnetic media, Phys. Rev., 81, pp. 869-880, (1951); Pecora L., Derivation and generalization of the Suhl spin-wave instability relations, Phys. Rev. B, 37, pp. 5473-5477, (1988); Anderson P., Suhl H., Instability in the motion of ferromagnets at high microwave power levels, Phys. Rev., 100, pp. 1788-1789, (1955); Skrotskii G., Alimov Y., Ferromagnetic resonance in a circularly polarized magnetic field of arbitrary amplitude, Sov. Phys. JETP, 35, pp. 1035-1037, (1959); Skrotskii G., Alimov Y., Effect of specimen shape on ferromagnetic resonance in a strong radio-frequency field, Sov. Phys. JETP, 36, pp. 899-901, (1959); Khapikov A., Dynamics of the magnetization reversal of a cylinder in an alternating magnetic field, JETP Lett., 55, pp. 352-356, (1992); Traxler T., Just W., Sauermann H., Dynamics of homogeneous magnetizations in strong transverse driving fields, Z. Phys. B, 99, pp. 285-295, (1996); Bertotti G., Serpico C., Mayergoyz I., Nonlinear magnetization dynamics under circularly polarized field, Phys. Rev. Lett., 86, pp. 724-727, (2001); Bertotti G., Mayergoyz I., Serpico C., Spin-wave instabilities in large-scale nonlinear magnetization dynamics, Phys. Rev. Lett., 87, pp. 217203-217211, (2001); Wiggins S., Introduction to Applied Nonlinear Dynamical Systems and Chaos, (1990); Hubbard J., West B., Differential Equations: a Dynamical Systems Approach, (1995); Perko L., Differential Equations and Dynamical Systems, (1996); Hale J., Kocak H., Dynamics and Bifurcations, (1991); Alvarez L., Pla O., Chubykalo O., Quasiperiodicity, bistability, and chaos in the Landau-Lifshitz equation, Phys. Rev. B, 61, pp. 11613-11617, (2000); Kuznetsov Y., Elements of Applied Bifurcation Theory, (1995); Stoner E., Wohlfarth W., A mechanism of magnetic hysteresis in heterogeneous alloys, Phil. Trans. Roy. Soc. A, 240, pp. 599-642, (1948); Serpico C., D'aquino M., Bertotti G., Mayergoyz I., Quasiperiodic magnetization dynamics in uniformly magnetized particles and films, J. Appl. Phys., 95, pp. 7052-7054, (2004); Guckenheimer J., Holmes P., Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields, (1997); Bertotti G., Mayergoyz I., Serpico C., Perturbation technique for LLG dynamics in uniformly magnetized bodies subject to rf fields, IEEE Trans. Magn., 38, pp. 2403-2405, (2002); Seagle D., Charap S., Artman J., Foldover in YIG, J. Appl. Phys., 57, pp. 3706-3708, (1985); Fetisov Y., Patton C., Sygonach V., Nonlinear ferromagnetic resonance and foldover in yttrium iron garnet thin films - inadequacy of the classical model, IEEE Trans. Magn., 35, pp. 4511-4521, (1999); Magni A., Bertotti G., Serpico C., Mayergoyz I., Dynamic generalization of Stoner-Wohlfarth model, J. Appl. Phys., 89, pp. 7451-7453, (2001); Bertotti G., Bonin R., Mayergoyz I., Serpico C., Generalized magnetostatic modes around large magnetization motions, J. Appl. Phys., 95, pp. 7046-7048, (2004); Bertotti G., Mayergoyz I., Serpico C., Generalized notion of spin-wave for large magnetization motion, J. Appl. Phys., 91, pp. 8656-8658, (2002); Fletcher P., Bell R., Ferrimagnetic resonance modes in spheres, J. Appl. Phys., 30, pp. 687-698, (1959); Arnold V., Mathematical Methods of Classical Mechanics, (1989); Landau L.D., Lifshitz E.M., Mechanics, (1976)","","","Elsevier","","","","","","","978-012480874-4","","","English","The Sci. of Hysteresis","Book chapter","Final","","Scopus","2-s2.0-64149130410" +"Jalil M.B.A.; Tan S.G.; Cheng X.Z.","Jalil, M.B.A. (7006821429); Tan, S.G. (8571745900); Cheng, X.Z. (10539190400)","7006821429; 8571745900; 10539190400","Advanced modeling techniques for micromagnetic systems","2007","Journal of Nanoscience and Nanotechnology","7","1","","46","64","18","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34447316467&partnerID=40&md5=a6810fb25795ba404ed2ade56d7b1890","Information Storage Materials Laboratory, ECE Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Data Storage Institute, DSI Building, National University of Singapore, Singapore 117608, 5 Engineering Drive 1, Off Kent Ridge Crescent, Singapore","Jalil M.B.A., Information Storage Materials Laboratory, ECE Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Tan S.G., Data Storage Institute, DSI Building, National University of Singapore, Singapore 117608, 5 Engineering Drive 1, Off Kent Ridge Crescent, Singapore; Cheng X.Z., Information Storage Materials Laboratory, ECE Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore","We present a review of micromagnetic and magnetotransport modeling methods which go beyond the standard model. We first give a brief overview of the standard micromagnetic model, which for (i) the steady-state (equilibrium) solution is based on the minimization of the free energy functional, and for (ii) the dynamical solution, relies on the numerical solution of the Landau-Lifshitz-Gilbert (LLG) equation. We present three complements to the standard model, i.e., (i) magnetotransport calculations based on ohmic conduction in the presence of the anisotropic magnetoresistance (AMR) effect, (ii) magnetotransport calculations based on spin-dependent tunneling in the presence of single charge tunneling (Coulomb blockade) effect, and (iii) stochastic micromagnetics, which incorporates the effects of thermal fluctuations via a white-noise thermal field in the LLG equation. All three complements are of practical importance: (i) magnetotransport model either in the ohmic or tunneling transport regimes, enables the conversion of the micromagnetic results to the measurable quantity of magnetoresistance ratio, while (ii) stochastic modeling is essential as the dimensions of the micromagnetic system reduces to the deep submicron regime and approaches the superparamagnetic limit. Copyright © 2007 American Scientific Publishers All rights reserved.","Coulomb Blockade; Magnetotransport; Micromagnetics; Spin-dependent Tunneling; Stochastic Magnetization Dynamics","Anisotropy; Biophysics; Computer Storage Devices; Electrochemistry; Electronics; Magnetics; Models, Statistical; Models, Theoretical; Stochastic Processes; Temperature; Thermodynamics; Electric diverters; Electric resistance; Energy conversion; Equations of state; Excavation; Magnetic field effects; Magnetic fields; Magnetic recording; Magnetism; Magnetoelectronics; Magnetoresistance; Nanostructured materials; Numerical methods; Paramagnetism; Spin fluctuations; Standards; Stochastic programming; Superparamagnetism; Tunneling (excavation); Advanced modeling techniques; Anisotropic magneto resistance (AMR); Charge tunneling; Deep sub-micron (DSM); Free-energy functional; Landau Lifshitz Gilbert (LLG) equations; Magneto transport; Magneto-resistance (MR) ratio; Micro magnetic modeling; Micromagnetic; Micromagnetic systems; Micromagnetics; Modeling methods; Numerical solutions; Ohmic conduction; Practical importance; Spin dependent tunneling; Standard Model (SM); Stochastic model (SM); Superparamagnetic limit; Thermal fluctuations; anisotropy; biophysics; data storage device; electrochemistry; electronics; magnetism; methodology; review; statistical model; statistics; temperature; theoretical model; thermodynamics; Stochastic models","","","","","","","Prinz G., Physics Today, 48, (1995); O'Handley R.C., Modern Magnetic Materials, (2000); Tsiantos V.D., Suess D., Scholz W., Schrefl T., Fidler J., J. Magn. Magn. Mater, 242, (2002); Hehn M., Ounadjela K., Bucher J.-P., Rousseaux F., Decanini D., Bartenlian B., Chappert C., Science, 272, (1996); Gu E., Ahmad E., Gray S.J., Daboo C., Bland J.A.C., Brown L.M., Ruhrig M., McGibbon A.J., Chapman J.N., Phys. Rev. Lett, 78, (1997); Chou S.Y., Proc. IEEE, 85, (1997); Johnson M., J. Magn. Magn. Mater, 156, (1996); Tehrani S., IEEE Trans. Magn, 35, (1999); Wolf S.A., Awschalom D.D., Buhrman R.A., Daughton J.M., von Molnar S., Roukes M.L., Chtchelkanova A.Y., Treger D.M., Science, 294, (2001); Zorpette G., IEEE Spectrum, 38, (2001); Landau L., Lifshitz E., Physik. Z. Sowjetunion, 8, (1935); Brown Jr. W.F., Micromagnetics, (1963); Fidler J., Schrefl T., J. Phys. D, 33, (2000); Brown W.F., Phys. Rev, 130, (1963); Schabes M.E., Aharoni A., IEEE Trans. Magn, 23, (1987); Chen W., Fredkin D.R., Koehler T.R., IEEE Trans. Magn, 29, (1993); Tako K.M., Schrefl T., Wongsam M.A., Chantrell R.W., J. Appl. 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Appl. Phys, 86, (1999); Jalil M.B.A., J. Appl. Phys, 93, (2003); Zhang L., Bain J.A., Zhu J.G., IEEE Trans. Magn, 38, (2002); Westmijze W.K., Philips Res. Rep, 8, (1953); Mallinson J.C., IEEE Trans. Magn, 26, (1990)","","","","","","","","","15334880","","","17455475","English","J. Nanosci. Nanotechnol.","Review","Final","","Scopus","2-s2.0-34447316467" +"Kanai Y.; Saiki M.; Yoshida K.","Kanai, Yasushi (56530175700); Saiki, Masahiko (15064617700); Yoshida, Kazuetsu (23017498800)","56530175700; 15064617700; 23017498800","Micromagnetic simulations of perpendicular single-pole-type head for various pole-tip structures","2007","IEEE Transactions on Magnetics","43","4","","1665","1668","3","9","10.1109/TMAG.2006.892268","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33947640568&doi=10.1109%2fTMAG.2006.892268&partnerID=40&md5=5094f960343419215023cc18e1f0732a","Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Department of Computer Science and Communication Engineering, Kogakuin University, Tokyo 163-8677, Japan","Kanai Y., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Saiki M., Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; Yoshida K., Department of Computer Science and Communication Engineering, Kogakuin University, Tokyo 163-8677, Japan","This paper describes the micromagnetic simulation of a single-pole-type head for a perpendicular magnetic recording. A Landau-Lifshitz-Gilbert calculation that treats the whole magnetic material micromagnetically is performed. The recording fields are investigated for various pole-tip structures. It is found that an optimum nonzero throat height exists that maximizes recording field strength. The addition of a trailing shield is found to be effective in regards to obtaining a larger recording field gradient. © 2007 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Micromagnetic simulation; Perpendicular magnetic recording; Single-pole-type (SPT) head","Magnetic fields; Magnetic materials; Magnetic recording; Magnetic shielding; Landau-Lifshitz-Gilbert (LLG) equations; Micromagnetic simulation; Perpendicular magnetic recording; Pole-tip structures; Single-pole-type (SPT) head; Microstructure","","","","","Promotion of Advanced Education and Research Program for Private Graduate Schools in 2005; Japan Society for the Promotion of Science, KAKEN, (15,560,311); Strategic Research Council, SRC","ACKNOWLEDGMENT This work was supported in part by a Grant in Aid for the Japan Society for the Promotion of Science (15,560,311), in part by a Grant in Aid for the Promotion of Advanced Education and Research Program for Private Graduate Schools in 2005, Japan, and in part by the Storage Research Consortium (SRC), Japan. The authors would like to thank the kind support by SRC, Japan. The authors also would like to acknowledge the use of LLG micromagnetic software from Central Research Laboratory, Hitachi, Limited.","Toshiba announced world's first commercial HDD that; Kanai Y., Matsubara R., Write field calculation for narrow track single pole head with thin layer of perpendicular medium, IEEE Trans. Magn, 38, 1, pp. 169-174, (2002); Kanai Y., Greaves S.J., Yamakawa K., Aoi H., Muraoka H., Nakamura Y., A single-pole-type head design for 400 Gb/in2 recording, IEEE Trans. Magn, 41, 2, pp. 687-695, (2005); Gao K.-Z., Bertram H.N., Transition jitter estimates in tilted and conventional perpendicular recording media at 1 Tb/in2, IEEE Trans. Magn, 39, 2, pp. 704-709, (2003); Yoshida K., Suzuki A., Yanagihara H., Calculations of magnetization configurations of SPT head using micromagnetic model, J. Magn. Magn. Mater, 287, pp. 83-88, (2005); Takano K., Micromagnetic-FEM models of a perpendicular writer and reader, IEEE Trans. Magn, 41, 2, pp. 696-701, (2005); Scholz W., Barta S., Micromagnetic modeling of head field rise time for high data-rate recording, IEEE Trans. Magn, 41, 2, pp. 702-706, (2005); Schrefl T., Schabes M.E., Suess D., Ertl O., Kirschner M., Dorfbauer F., Hrkac G., Fidler J., Partitioning of the perpendicular write field into head and SUL contributions, IEEE Trans. Magn, 41, 10, pp. 3064-3066, (2005); Heinonen O., Bozeman P., FEM and micromagnetic modeling of perpendicular writers, J. Appl. Phys, 99, 8, (2006); Tsang C., Bonhote C., Dai Q., Do H., Knigge B., Ikeda Y., Le Q., Lengsfield B., Lille J., Li J., MacDonald S., Moser A., Nayak V., Payne R., Robertson N., Schabes M., Smith N., Takano K., van der Heijden P., Weresin W., Williams M., Xiao M., Head challenges for perpendicular recording at high areal density, IEEE Trans. Magn, 42, 2, pp. 145-150, (2006)","Y. Kanai; Department of Information and Electronics Engineering, Faculty of Engineering, Niigata Institute of Technology, Kashiwazaki 945-1195, Japan; email: kanai@iee.niit.ac.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-33947640568" +"Forestiere C.; D'Aquino M.; Miano G.; Serpico C.","Forestiere, C. (26032511200); D'Aquino, M. (9732823500); Miano, G. (7006758103); Serpico, C. (23013514800)","26032511200; 9732823500; 7006758103; 23013514800","Finite element computations of resonant modes for small magnetic particles","2009","Journal of Applied Physics","105","7","07D312","","","","4","10.1063/1.3072774","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-65249141841&doi=10.1063%2f1.3072774&partnerID=40&md5=45f644b28200f0f38a5d163c1b1a43f4","Department of Electrical Engineering, Universit̀ Degli Studi di Napoli Federico II, Napoli, 80125, Italy; Department of Technology, Universit̀ di Napoli Parthenope, Napoli, 80143, Italy","Forestiere C., Department of Electrical Engineering, Universit̀ Degli Studi di Napoli Federico II, Napoli, 80125, Italy; D'Aquino M., Department of Technology, Universit̀ di Napoli Parthenope, Napoli, 80143, Italy; Miano G., Department of Electrical Engineering, Universit̀ Degli Studi di Napoli Federico II, Napoli, 80125, Italy; Serpico C., Department of Electrical Engineering, Universit̀ Degli Studi di Napoli Federico II, Napoli, 80125, Italy","The oscillations of a chain of ferromagnetic nanoparticles around a saturated spatially uniform equilibrium are analyzed by solving the linearized Landau-Lifshitz-Gilbert (LLG) equation. The linearized LLG equation is recast in the form of a generalized eigenvalue problem for suitable self-adjoint operators connected to the micromagnetic effective field, which accounts for exchange, magnetostatic, anisotropy, and Zeeman interactions. The generalized eigenvalue problem is solved numerically by the finite element method, which allows one to treat accurately complex geometries and preserves the structural properties of the continuum problem. The natural frequencies and the spatial distribution of the mode amplitudes are computed for chains composed of several nanoparticles (sphere and ellipsoid). The effects of the interaction between the nanoparticles and the limit of validity of the point dipole approximation are discussed. © 2009 American Institute of Physics.","","Linearization; Mathematical operators; Nanoparticles; Size distribution; Switching systems; Complex geometries; Continuum problems; Effective fields; Ferromagnetic nanoparticles; Finite element computations; Finite elements; Generalized eigenvalue problems; Landau-Lifshitz-Gilbert equations; Llg equations; Magnetic particles; Micromagnetic; Mode amplitudes; Point-dipole approximations; Resonant modes; Self-adjoint operators; Spatial distributions; Zeeman interactions; Eigenvalues and eigenfunctions","","","","","","","Jung S., Watkins B., De Long L., Ketterson J.B., Chandrasekhar V., Phys. Rev. B, 66, (2002); Rivkin K., Heifetz A., Sievert P.R., Ketterson J.B., Phys. Rev. B, 70, (2004); Walker L.R., Phys. Rev., 105, (1957); Aharoni A., J. Appl. Phys., 69, (1991); Brown Jr. W.F., Micromagnetics, (1963); Grimsditch M., Phys. Rev. B, 69, (2004); D'Aquino M., Serpico C., Miano G., Bertotti G., Mayergoyz I.D., Physica B, 403, (2008); D'Aquino M., Serpico C., Miano G., Bertotti G., IEEE Trans. Magn., 44, (2008); Graglia R.D., IEEE Trans. Antennas Propag., 41, (1993)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-65249141841" +"Hamdache K.; Tilioua M.","Hamdache, K. (6701901951); Tilioua, M. (6507877823)","6701901951; 6507877823","The Landau-Lifshitz equations and the damping parameter","2006","Bollettino della Unione Matematica Italiana B","9","2","","283","297","14","1","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33746909530&partnerID=40&md5=8973e379080d79b01062603940dccebe","Centre de Mathématiques Appliquées, CNRS UMR 7641, Ecole Polytechnique, 91128 Palaiseau Cedex, France","Hamdache K., Centre de Mathématiques Appliquées, CNRS UMR 7641, Ecole Polytechnique, 91128 Palaiseau Cedex, France; Tilioua M., Centre de Mathématiques Appliquées, CNRS UMR 7641, Ecole Polytechnique, 91128 Palaiseau Cedex, France","The present paper is particularly devoted to the damping effect in ferromagnetic materials. We are interested in determining the sensitivity of the LLG method solution to the phenomenological damping parameter a. We discuss the behaviour of the global weak solutions with finite energy of the Landau-Lifshitz equations when the damping parameter a tends either to 0 (underdamped case) or +∞ (overdamped case).","","","","","","","","","Alouges F., Soyeur A., On global weak solutions for Landau-Lifshitz equations: Existence and nonuniqueness, Nonlinear Anal., 18, 11, pp. 1071-1084, (1992); Bertsch M., Dal Passo R., Van Der Hour R., Nonuniqueness for the heat flow of harmonic maps on the disk, Arch. Ration. Mech. Anal., 161, 2, pp. 93-112, (2002); Chang N.-H., Shatah J., Uhlenbeck K., Schrödinger maps, Comm. Pure Appl. Math., 53, 5, pp. 590-602, (2000); Cullity B.D., Introduction to Magnetic Materials, (1972); E. W., Selected problems in materials science, Mathematics Unlimited-2001 and Beyond. Part I, II, pp. 407-432, (2001); Gustafson S., Shatah J., The stability of localized solutions of Landau-Lifshitz equations, Comm. Pure Appl. Math., 55, 9, pp. 1136-1159, (2002); Hamdache K., Homogenization of Layered Ferromagnetic Media, (2002); Hamdache K., Tilioua M., Interlayer exchange coupling for ferromagnets through spacers, SIAM J. Appl. Math., 64, 3, pp. 1077-1097, (2004); Ingvarsson S.P., Magnetization Dynamics in Transition Metal Ferromagnets Studied by Magneto-tunneling and Ferromagnetic Resonance, (2001); Mizohata S., The Theory of Partial Differential Equations, (1973); Moser R., Partial Regularity for the Landau-Lifshitz Equation in Small Dimensions, (2002); Pazy A., Semigroups of linear operators and applications to partial differential equations, Applied Mathematical Sciences, 44, (1983); Shatah J., Struwe M., The Cauchy problem for wave maps, Int. Math. Res. Not., 11, pp. 555-571, (2002); Struwe M., On the evolution of harmonic mappings of Riemannian surfaces, Comment. Math. Helv., 60, 4, pp. 558-581, (1985); Sulem P.-L., Sulem C., Bardos C., On the continuous limit for a system of classical spins, Comm. Math. Phys., 107, 3, pp. 431-454, (1986); Visintin A., On Landau-Lifshitz equations for ferromagnetism, Japan J. Appl. Math., 2, 1, pp. 69-84, (1985)","K. Hamdache; Centre de Mathématiques Appliquées, CNRS UMR 7641, Ecole Polytechnique, 91128 Palaiseau Cedex, France; email: hamdache@cmapx.polytechnique.fr","","","","","","","","03924041","","","","English","Boll. Unione Mat. Ital. B","Article","Final","","Scopus","2-s2.0-33746909530" +"Brataas A.; Tserkovnyak Y.; Bauer G.E.W.","Brataas, Arne (7004143305); Tserkovnyak, Yaroslav (6701709732); Bauer, Gerrit E. W. (7402068004)","7004143305; 6701709732; 7402068004","Magnetization dissipation in ferromagnets from scattering theory","2011","Physical Review B - Condensed Matter and Materials Physics","84","5","054416","","","","49","10.1103/PhysRevB.84.054416","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-80052286744&doi=10.1103%2fPhysRevB.84.054416&partnerID=40&md5=cf5bd5b6c1db5abc14169fe2ebc5f4c0","Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, United States; Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan; Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, Lorentzweg 1, Netherlands","Brataas A., Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Tserkovnyak Y., Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, United States; Bauer G.E.W., Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan, Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, Lorentzweg 1, Netherlands","The magnetization dynamics of ferromagnets is often formulated in terms of the Landau-Lifshitz-Gilbert (LLG) equation. The reactive part of this equation describes the response of the magnetization in terms of effective fields, whereas the dissipative part is parametrized by the Gilbert damping tensor. We formulate a scattering theory for the magnetization dynamics and map this description on the linearized LLG equation by attaching electric contacts to the ferromagnet. The reactive part can then be expressed in terms of the static scattering matrix. The dissipative contribution to the low-frequency magnetization dynamics can be described as an adiabatic energy pumping process to the electronic subsystem by the time-dependent magnetization. The Gilbert damping tensor depends on the time derivative of the scattering matrix as a function of the magnetization direction. By the fluctuation-dissipation theorem, the fluctuations of the effective fields can also be formulated in terms of the quasistatic scattering matrix. The theory is formulated for general magnetization textures and worked out for monodomain precessions and domain-wall motions. We prove that the Gilbert damping from scattering theory is identical to the result obtained by the Kubo formalism. © 2011 American Physical Society.","","","","","","","National Science Foundation, NSF, (0840965); Seventh Framework Programme, FP7, (257159)","","Heinrich B., Fraitova D., Kambersky V., Phys. Status Solidi, 23, (1967); Kambersky V., Can. J. Phys., 48, (1970); Korenman V., Prange R.E., Phys. Rev. B, 6, (1972); Lutovinov V.S., Reizer M.Y., ZETP, 77, (1979); Safonov V.L., Bertram H.N., Phys. Rev. B, 61, (2000); Kunes J., Kambersky V., Phys. Rev. B, 65, (2002); Kambersky V., Phys. Rev. B, 76, (2007); Garate I., MacDonald A.H., Phys. Rev. B, 79, (2009); Bland J.A.C., Heinrich B., Ultrathin Magnetic Structures III: Fundamentals of Nanomagnetism, (2004); Stiles M.D., Miltat J., Spin-transfer torque and dynamics, Topics in Applied Physics, 101, pp. 225-308, (2006); Foros J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. B, 78, (2008); Zhang S., Zhang S.S.-L., Phys. Rev. Lett., 102, (2009); Wong C.H., Tserkovnyak Y., Phys. Rev. B, 80, (2009); Brown W.F., Phys. Rev., 130, (1963); Waintal X., Myers E.B., Brouwer P.W., Ralph D.C., Role of spin-dependent interface scattering in generating current-induced torques in magnetic multilayers, Physical Review B - Condensed Matter and Materials Physics, 62, 18, pp. 12317-12327, (2000); Brataas A., Nazarov Yu.V., Bauer G.E.W., Phys. Rev. Lett., 84, (2000); Brataas A., Bauer G.E.W., Kelly P.J., Non-collinear magnetoelectronics, Physics Reports, 427, 4, pp. 157-255, (2006); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Halperin B.I., Nonlocal magnetization dynamics in ferromagnetic heterostructures, Reviews of Modern Physics, 77, 4, pp. 1375-1421, (2005); Bruno P., Phys. Rev. B, 52, (1995); Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 101, (2008); Liu Y., Yuan Z., Starikov A.A., Kelly P.J.; Brataas A., Tserkovnyak Y., Bauer G.E.W., Halperin B.I., Phys. Rev. B, 66, (2002); Wang X., Bauer G.E.W., Van Wees B.J., Brataas A., Tserkovnyak Y., Voltage generation by ferromagnetic resonance at a nonmagnet to ferromagnet contact, Physical Review Letters, 97, 21, (2006); Heinrich B., Tserkovnyak Y., Woltersdorf G., Brataas A., Urban R., Bauer G.E.W., Phys. Rev. Lett., 90, (2003); Costache M.V., Sladkov M., Watts S.M., Van Der Wal C.H., Van Wees B.J., Electrical detection of spin pumping due to the precessing magnetization of a single ferromagnet, Physical Review Letters, 97, 21, (2006); Woltersdorf G., Mosendz O., Heinrich B., Back C.H., Magnetization dynamics due to pure Spin currents in magnetic double layers, Physical Review Letters, 99, 24, (2007); Hals K.M.D., Nguyen A.K., Brataas A., Phys. Rev. Lett., 102, (2009); Hals K.M.D., Tserkovnyak Y., Bratas A., Europhys. Lett., 90, (2010); Gilmore K., Idzerda Y.U., Stiles M.D., Identification of the dominant precession-damping mechanism in Fe, Co, and Ni by first-principles calculations, Physical Review Letters, 99, 2, (2007); Starikov A.A., Kelly P.J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Phys. Rev. Lett., 105, (2010); Ebert H., Mankovsky S., Koedderitzsh D., Kelly P.J.; Kubler J., Theory of Itinerant Electron Magnetism, (2000); Kohn W., Rev. Mod. Phys., 71, (1999); Zangwill A., Soven P., Phys. Rev. Lett., 45, (1980); Gross E.K.U., Kohn W., Phys. Rev. Lett., 55, (1985); Tretiakov O.A., Clarke D., Chern G.-W., Bazaliy Ya.B., Tchernyshyov O., Dynamics of domain walls in magnetic nanostrips, Physical Review Letters, 100, 12, (2008); Clarke D.J., Tretiakov O.A., Chern G.W., Bazaliy Ya.B., Tchernyshyov O., Phys. Rev. B, 78, (2008); Goussev A., Robbins J.M., Slastikov V., Phys. Rev. Lett., 104, (2010); Schryer N.L., Walker L.R., J. Appl. Phys., 45, (1974); Nazarov Yu.V., Blanter Y., Quantum Transport-Introduction to Nanoscience, (2009); Bauer G.E.W., Phys. Rev. Lett., 69, (1992); Avishai Y., Band Y.B., Phys. Rev. B, 32, (1985); Avron J.E., Elgart A., Graf G.M., Sadun L., Phys. Rev. Lett., 87, (2001); Moskalets M., Buttiker M., Phys. Rev. B, 66, (2002); Moskalets M., Buttiker M., Phys. Rev. B, 66, (2002); Arrachea L., Moskalets M., Energy Transport and Heat Production in Quantum Engines, Handbook of Nanophysics: Nanomedicine and Nanorobotics, (2010); Foros J., Brataas A., Tserkovnyak Y., Bauer G.E.W., Magnetization noise in magnetoelectronic nanostructures, Physical Review Letters, 95, 1, pp. 1-4, (2005); Mahan G.D., Many-particle Physics, (2010); Simanek E., Heinrich B., Phys. Rev. B, 67, (2003); Fisher D.S., Lee P.A., Phys. Rev. B, 23, (1981); Mello P.A., Kumar N., Quantum Transport in Mesoscopic Systems, (2005); Bennett S.D., Maassen J., Clerk A.A., Phys. Rev. Lett., 105, (2010); Bode N., Kusminskiy S.V., Egger R., Von Oppen F.; Buttiker M., Thomas H., Pretre A., Z. Phys. B, 94, (1994); Brouwer P.W., Phys. Rev. B, 58, (1998); Wang B., Wang J., Phys. Rev. B, 66, (2002); Buttiker M., Phys. Rev. B, 46, (1992); Rammer J., Smith H., Rev. Mod. Phys., 58, (1985)","A. Brataas; Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; email: Arne.Brataas@ntnu.no","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Bronze Open Access; Green Open Access","Scopus","2-s2.0-80052286744" +"Nigam A.; Munira K.; Ghosh A.; Wolf S.; Chen E.; Stan M.R.","Nigam, Anurag (36844605300); Munira, Kamaram (36844384200); Ghosh, Avik (7403963862); Wolf, Stu (7402621506); Chen, Eugene (57203756082); Stan, Mircea R. (7004403141)","36844605300; 36844384200; 7403963862; 7402621506; 57203756082; 7004403141","Self consistent parameterized physical MTJ compact model for STT-RAM","2010","Proceedings of the International Semiconductor Conference, CAS","2","","5650558","423","426","3","11","10.1109/SMICND.2010.5650558","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-78651104421&doi=10.1109%2fSMICND.2010.5650558&partnerID=40&md5=4c5d615da76cd84c634310a85e70f32c","Charles L. Brown ECE Dept., University of Virginia, United States; Grandis, Inc., United States","Nigam A., Charles L. Brown ECE Dept., University of Virginia, United States; Munira K., Charles L. Brown ECE Dept., University of Virginia, United States; Ghosh A., Charles L. Brown ECE Dept., University of Virginia, United States; Wolf S., Charles L. Brown ECE Dept., University of Virginia, United States; Chen E., Grandis, Inc., United States; Stan M.R., Charles L. Brown ECE Dept., University of Virginia, United States","We present a physical compact model for magnetic tunnel junction (MTJ). Landau-Lifshitz-Gilbert (LLG) differential equation is solved in SPICE to derive the transient characteristics of MTJ. A modified version of the Simmons tunnel current equation captures the steady state properties of MTJ. The model results are validated with published experimental data. © 2010 IEEE.","Compact circuit model; MTJ; STT-RAM","Circuit theory; Differential equations; Tunnel junctions; Circuit models; Compact model; Experimental data; Landau-Lifshitz-Gilbert; Magnetic tunnel junction; Model results; MTJ; Parameterized; Steady state properties; STT-RAM; Transient characteristic; Tunnel currents; Magnetic devices","","","","","","","Huai Y., Spin-transfer torque MRAM (STTMRAM): Challenges and prospects, AAPPS Bulletin, 18, 6, (2008); Zhou P., Et al., Energy reduction for STT-RAM using early write termination, ICCAD, (2009); Lee S., Et al., Advanced HSPICE macromodel for magnetic tunnel junction, Jpn. J. Appl. Phys., 44, pp. 2696-2700, (2005); Zhao W., Et al., Macro-model of spin-transfer torque based magnetic tunnel junction device for hybrid magnetic-CMOS design, BMSW IEEE, (2006); Ono K., Et al., A disturbance-free read scheme and a compact stochastic-spin-dynamics- based MTJ circuit model for Gb-scale SPRAM, IEDM, (2010); Duke C.B., Tunneling in Solids, (1969); Julliere M., Phys. Lett., 54 A, (1975); Slonczeski J.C., Conductance and exchange coupling of two ferromagnets separated by a tunneling barrier, Phys. Rev. B, 39, 6995, (1989); Simmons J.G., Electrical tunnel effect between dissimilar electrodes separated by a thin insulating film, J.Appl. Phys., 34, 2581, (1963); Majumdar S., Et al., New J. Phys, 11; Sun J.Z., Spin-current interaction with a monodomain magnetic body: A model study, Physical Review B, 62, 520, (2000); Kuboto H., Et al., Quantitative measurement of voltage dependence of spin-transfer torque in MgObased magnetic tunnel junctions, Nature, (2007); Chen E., Et al., Advances and future prospects of STT-RAM, Intermag/MMM Conference, (2010)","","","","IEEE-Electron Devices Society; Ministry of Education, Research, Youth and Sports; IEEE-Romania Section; Electron Device Chapter; Centrotherm Thermal Solutions GmbH+Co.KG","2010 33rd International Semiconductor Conference, CAS 2010","11 October 2010 through 13 October 2010","Sinaia","83259","","978-142445781-6","","","English","Proc Int Semicond Conf CAS","Conference paper","Final","","Scopus","2-s2.0-78651104421" +"Chen A.P.; García C.; Zhukov A.; Domínguez L.; Blanco J.M.; Gonzalez J.","Chen, A.P. (59066314900); García, C. (58447048300); Zhukov, A. (56160242800); Domínguez, L. (7103341989); Blanco, J.M. (58904538900); Gonzalez, J. (7404493359)","59066314900; 58447048300; 56160242800; 7103341989; 58904538900; 7404493359","Influence of the ac magnetic field frequency on the magnetoimpedance of amorphous wire","2006","Journal of Physics D: Applied Physics","39","9","","1718","1723","5","5","10.1088/0022-3727/39/9/002","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33646410102&doi=10.1088%2f0022-3727%2f39%2f9%2f002&partnerID=40&md5=521f10f2bcf77badd8a2ba0f9675c438","Department of Material Physics, Chemistry Faculty, 20080 San Sebastian, PO Box 1072, Spain; Department of Applied Physics I, EUITI, UPV/EHU, 20080 San Sebastian, Pl. Europa 1, Spain","Chen A.P., Department of Material Physics, Chemistry Faculty, 20080 San Sebastian, PO Box 1072, Spain; García C., Department of Material Physics, Chemistry Faculty, 20080 San Sebastian, PO Box 1072, Spain; Zhukov A., Department of Applied Physics I, EUITI, UPV/EHU, 20080 San Sebastian, Pl. Europa 1, Spain; Domínguez L., Department of Material Physics, Chemistry Faculty, 20080 San Sebastian, PO Box 1072, Spain; Blanco J.M., Department of Applied Physics I, EUITI, UPV/EHU, 20080 San Sebastian, Pl. Europa 1, Spain; Gonzalez J., Department of Material Physics, Chemistry Faculty, 20080 San Sebastian, PO Box 1072, Spain","Experimental and theoretical studies on the influence of ac magnetic field frequency on the axial diagonal (ζzz) and off-diagonal (ζΦz) components of the magnetoimpedance (MI) tensor in (Co0.94Fe0.06)72.5Si12.5B 15 amorphous wires have been performed. The frequency (f) of an ac current flowing along the wire was varied from 1 to 20 MHz with the current amplitude less than 15 mA. In order to enhance the ζΦz component, the amorphous wire was submitted to torsion annealing for developing and preserving a helical magnetic anisotropy in the surface of the wire. The experimental measurements show that the value of the impedance is proportional to the square-root of the ac current frequency, √f, in the vicinity of Hex < HK and this increase is due to the contribution of the resistance (real part of the impedance). The measurements also indicate that the peaks of the MI curve shift slightly towards higher field values with increasing f. In a theoretical study the magnetoimpedance expressions ζzz and ζΦz have been deduced using the Faraday law in combination with the solutions of the Maxwell and Landau-Lifshitz-Gilbert (LLG) equations. By analysing quantitatively the spectra of ζzz and ζΦz, the phenomenon of the shift in the peaks of the MI curve with f has been considered as a characteristic of the helical anisotropy in the domain structure of the wire surface. © 2006 IOP Publishing Ltd.","","Amorphous materials; Anisotropy; Annealing; Magnetic fields; Numerical analysis; Tensors; Helical magnetic anisotropy; Landau-Lifshitz-Gilbert (LLG); MI curve shifts; Torsion annealing; Magnetoelectric effects","","","","","","","Beach R.S., Berkowitz A.E., Appl. Phys. Lett., 64, (1994); Panina L.V., Mohri K., Appl. Phys. Lett., 65, (1994); Velasquez J., Vazquez M., Chen D.-X., Hernando A., Phys. Rev. B, 50, (1994); Rao K.V., Humphrey F.B., Costa-Kramer J.L., J. Appl. Phys., 76, (1994); Mohri K., Panina L.V., Uchiyama K.T., Bushida K., Noda M., IEEE Trans. Magn., 31, (1995); Panina L.V., Mohri K., Bushida K., Noda M., IEEE Trans. Magn., 31, (1996); Vazquez M., Hernando A., J. Phys. D: Appl. Phys., 29, (1996); Yelon A., Menard D., Britel M., Ciureanu P., Appl. Phys. Lett., 69, (1996); Makhnovskiy D.P., Panina L.V., Mapps D.J., J. Appl. Phys., 87, (2000); Makhnovskiy D.P., Panina L.V., Mapps D.J., Phys. Rev. B, 63, (2001); Chen A.P., Britel M.R., Zhukova V., Zhukov A., Dominguez L., Chizhik A., Blanco J.M., Gonzalez J., IEEE Trans. Magn., 40, (2004); Machado F.L.A., Rezende S.M., Phys. Rev. B, 51, (1955); Smonner R.L., Chien C.S., J. Appl. Phys. Lett., 67, (1995); Knobel M., Vazquez M., Giant K.L., Magnetoimpedance, Handbook of Magnetic Materials, 15; Aragoneses P., Blanco J.M., Dominguez L., Gonzalez J., Kulakowski K., J. Magn. Magn. Mat., 168, (1997); Blanco J.M., Zhukov A., Gonzalez J., J. Phys. D: Appl. Phys., 32, (1999); Blanco J.M., Zhukov A., Gonzalez J., J. Appl. Phys., 87, (2000); Zhukova V.A., Chizhik A.B., Gonzalez J., Makhnovskiy D.P., Panina L.V., Mapps D.J., Zhukov A.P., J. Magn. Magn. Mater., 249, (2002); Duque J.G.S., Gomez-Polo C., Yelon A., Ciureanu P., De Araujo A.E.P., Knobel M., J. Magn. Magn. Mat., 271, (2004); Chen A.P., Zhukova V., Zhukov A., Dominguez L., Chizhik A., Blanco J.M., Gonzalez J., J. Phys. D: Appl. Phys., 37, (2004)","A. Zhukov; Department of Applied Physics I, EUITI, UPV/EHU, 20080 San Sebastian, Pl. Europa 1, Spain; email: wupzhuka@sp.ehu.es","","","","","","","","13616463","","JPAPB","","English","J Phys D","Article","Final","","Scopus","2-s2.0-33646410102" +"Wu L.Z.; Ding J.; Neo C.P.; Chen L.F.; Ong C.K.","Wu, L.Z. (56127393700); Ding, J. (35848560700); Neo, C.P. (6602700057); Chen, L.F. (36342256700); Ong, C.K. (35467147500)","56127393700; 35848560700; 6602700057; 36342256700; 35467147500","Studies of high-frequency magnetic permeability of rod-shaped CrO 2 nanoparticles","2007","Physica Status Solidi (A) Applications and Materials Science","204","3","","755","762","7","6","10.1002/pssa.200622015","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-34547186705&doi=10.1002%2fpssa.200622015&partnerID=40&md5=dcfc07dc80841ce0a1a614f7d39fc6e4","Department of Materials Science and Engineering, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Temasek Laboratories, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore","Wu L.Z., Department of Materials Science and Engineering, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Ding J., Temasek Laboratories, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Neo C.P., Department of Materials Science and Engineering, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Chen L.F., Temasek Laboratories, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; Ong C.K., Center for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore","Rod-shaped CrO 2 nanoparticles with an aspect ratio of around 8:1 were studied in this work. The high-frequency properties (complex magnetic permeability, electric permittivity and reflection coefficient) have been measured on a composite consisting of 20 vol% of rod-shaped CrO 2 nanoparticles in a nonmagnetic epoxy resin matrix. The intrinsic magnetic permeability was calculated using an analytical model derived from the Landau-Lifshitz-Gilbert (LLG) equation. The effective permeability of the composite consisting of rod-shaped CrO 2 particles embedded in a nonmagnetic matrix (epoxy resin) was calculated using an effective medium theory for randomly orientated ellipsoidal inclusions. The comparison of the experimental values of the effective permeability with the analytical calculation showed that a relatively good agreement was obtained when the interparticle interactions were taken into the consideration. The results showed that CrO 2 have a natural resonance frequency at around 8 GHz. The microwave absorbing properties of the composite of rod-shaped CrO 2 nanoparticles and epoxy resin were studied. The calculated results of reflection coefficient indicated that the rod-shaped CrO 2 nanoparticles may be interesting for microwave absorption, particularly for the high frequency range around 10 GHz (X-band). © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.","","Aspect ratio; Epoxy resins; Inclusions; Magnetic permeability; Nanoparticles; Natural frequencies; Reflection; Analytical model; Electric permittivity; Nonmagnetic matrix; Rod-shaped; Chromium compounds","","","","","","","Schwarz K., J. Phys. F: Met. Phys, 16, (1986); O'Handley R.C., Modem Magnetic Materials Principles and Applications, (2000); Naito Y., Suetaki K., IEEE Trans. Microw. Theory Tech, MTT-19, (1971); Musal H.M., Hahn H.T., IEEE Trans. Magn, 25, (1989); Grimes C.A., IEEE Aerospace Applications Conference, Steamboat Springs, 31 Jan.-5 Feb. 1993 (Digest Inst. of Electrical and Electronics Eng., Inc.); Vinoy K.J., Jha R.M., Sadhana, 20, (1995); Knott E.F., Shaeffer J.F., Tuley M.T., Radar Cross Section, (1993); Grimes C.A., J. Appl. Phys, 69, (1991); Ding J., Shi Y., Chen L.F., Deng C.R., Fuh S.H., Li Y., J. Magn. Magn. Mater, 247, (2002); Berthault A., Rousselle D., Zerah G., J. Magn. Magn. Mater, 112, (1992); Matsumoto M., Miyata Y., IEEE Trans. Magn, 33, (1997); Wu M., Zhao Z., He H., Yao X., J. Magn. Magn. Mater, 217, (2000); Wu M.Z., He H.H., Zhao Z.S., Yao X., J. Phys. D: Appl. Phys, 33, (2000); Sihvola A., Electromagnetic Mixing Formulas and Applications, (1999); Ding J., Liu Y., McCormick P.G., Street R., J. Appl. Phys, 75, (1994); Soohoo R.F., Microwave Magnetics, (1985); Zhu J.-G., Bertram H.N., J. Appl. Phys, 63, (1988); Vos M.J., Brott R.L., Zhu J.-G., Carlson L.W., IEEE Trans. Magn, 29, (1993); Chantrell R.W., Coverdale G.N., Hilo M.E., O'Grady K., J. Magn. Magn. Mater, 157-158, (1996); Jiles D., Introduction to Magnetism and Magnetic Materials, (1998); Yu T., Shen Z.X., Lin J.Y., Ding J., J. Phys.: Condens. Matter, 15, (2003); Wu L.Z., Ding J., Jiang H.B., Neo C.P., Chen L.F., Ong C.K., J. Appl. Phys, 99, (2006); Grimes C.A., Grimes D.M., Phys. Rev. B, 43, (1991); Gelin P., Queffelec P., Pennec F.L., J. Appl. Phys, 98, (2005)","J. Ding; Temasek Laboratories, National University of Singapore, Singapore 119260, 10 Kent Ridge Crescent, Singapore; email: msedingj@nus.edu.sg","","","","","","","","18626319","","PSSAB","","English","Phys. Status Solidi A Appl. Mater. Sci.","Article","Final","","Scopus","2-s2.0-34547186705" +"Nakahata Y.; Todaka T.; Enokizono M.","Nakahata, Yasushi (16029172400); Todaka, Takashi (7006715391); Enokizono, Masato (7102846085)","16029172400; 7006715391; 7102846085","Magnetization process simulation of Nd-Fe-B magnets taking the demagnetization phenomenon into account","2011","IEEE Transactions on Magnetics","47","5","5754764","1102","1105","3","9","10.1109/TMAG.2010.2072985","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-79955536576&doi=10.1109%2fTMAG.2010.2072985&partnerID=40&md5=db548516c187a192f1caa3e164f05981","Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, Japan","Nakahata Y., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, Japan; Todaka T., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, Japan; Enokizono M., Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, Japan","This paper presents results obtained from a numerical simulation of the magnetization distribution of Nd-Fe-B magnets. We used the three-dimensional Variable Magnetization and the Stoner-Wohlfarth (VMSW) method in the initial magnetization process. In the residual-magnetization and demagnetization processes, we used the magnetization equation of motion, which can be described by the Landau-Lifshitz-Gilbert (LLG) equation. The calculation results were compared to the measured results to verify the accuracy of numerical simulation. © 2011 IEEE.","Demagnetization phenomenon; Landau-Lifshitz-Gilbert (LLG) equation; magnetization process simulation; Nd-Fe-B magnet; Variable Magnetization and Stoner-Wohlfarth (VMSW) method","Demagnetization; Equations of motion; Iron alloys; Magnetization; Magnets; Numerical models; Calculation results; Demagnetization process; Equation of motion; Landau-Lifshitz-Gilbert equations; Magnetization distribution; Nd-Fe-B magnets; Residual magnetization; Stoner-Wohlfarth; Neodymium alloys","","","","","","","Mohri Fumihito, New method for magnetic field computation on anisotropic permanent magnets, International journal of applied electromagnetics in materials, 3, 4, pp. 241-248, (1993); Nakahata Y., Todaka T., Enokizono M., Magnetization process simulation of anisotropic permanent magnets by using the three-dimensional VMSW method, IEEE Transactions on Magnetics, 44, 6, pp. 858-861, (2008); Brown Jr. W.F., Micromagnetics, (1978); Nakatani Y., Uesaka Y., Hayashi H., Direct solution of the Landau-Lifshitz-Gilbert equation for micromagnetics, Jpn. J. Appl. Phys., 20, pp. 2485-2507, (1989)","Y. Nakahata; Department of Electrical and Electronic Engineering, Faculty of Engineering, Oita University, Oita 870-1192, Japan; email: y.nakahata@oita-mag.jp","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-79955536576" +"Yuan S.; De Raedt H.; Miyashita S.","Yuan, S. (14822758400); De Raedt, H. (7006123039); Miyashita, S. (7102333760)","14822758400; 7006123039; 7102333760","Quantum dynamics of spin wave propagation through domain walls","2006","Journal of the Physical Society of Japan","75","8","084703","","","","5","10.1143/JPSJ.75.084703","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33847322132&doi=10.1143%2fJPSJ.75.084703&partnerID=40&md5=9a71cebf2edceb7f667906c8631cdb1c","Department of Applied Physics, Materials Science Center, University of Groningen, NL-9747 AG Groningen, Nijenborgh 4, Netherlands; Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; CREST, JST, Kawaguchi, Saitama 332-0012, 4-1-8 Honcho, Japan","Yuan S., Department of Applied Physics, Materials Science Center, University of Groningen, NL-9747 AG Groningen, Nijenborgh 4, Netherlands; De Raedt H., Department of Applied Physics, Materials Science Center, University of Groningen, NL-9747 AG Groningen, Nijenborgh 4, Netherlands; Miyashita S., Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan, CREST, JST, Kawaguchi, Saitama 332-0012, 4-1-8 Honcho, Japan","Through numerical solution of the time-dependent Schrödinger equation, we demonstrate that magnetic chains with uniaxial anisotropy support stable structures, separating ferromagnetic domains of opposite magnetization. These structures, domain walls in a quantum system, are shown to remain stable if they interact with a spin wave. We find that a domain wall transmits the longitudinal component of the spin excitations only. Our results suggests that continuous, classical spin models described by LLG equation cannot be used to describe spin wave-domain wall interaction in microscopic magnetic systems. ©2006 The Physical Society of Japan.","Domain wall; Nanomagnetic; Quantum spin model; Schrödinger equation","","","","","","","","Atkinson D., Allwood D.A., Xiong G., Cooke M.D., Faulkner C.C., Cowburn R.P., Nat. Mater, 2, (2003); Saitoh E., Miyajima H., Yamaoka T., Tatara G., Nature, 432, (2004); Charppert C., Devolder T., Nature, 432, (2004); Nakamura K., Sasada T., Phys. Lett. A, 48, (1974); Nakamura K., Sasada T., J. Phys. C, 11, (1978); Mikeska H.J., Miyashita S., Ristow G.H., J. Phys.: Condens. Matter, 3, (1991); Hertel R., Wulfhekel W., Kirschner J., Phys. Rev. Lett, 93, (2004); Kajiwara T., Nakano M., Kaneko Y., Takaishi S., Ito T., Yamashita M., Igashira-Kamiyama A., Nojiri H., Ono Y., Kojima N., J. Am. Chem. Soc, 127, (2005); Mito M., Deguchi H., Tajiri T., Takagi S., Yamashita M., Miyasaka H., Phys. Rev. B, 72, (2005); Kageyama H., Yoshimura K., Kosuge K., Azuma M., Takano M., Mitamura H., Goto T., J. Phys. Soc. Jpn, 66, (1997); Maignan A., Michel C., Masset A.C., Martin C., Raveau B., Eur. Phys. J. B, 15, (2000); Bose S., Phys. Rev. Lett, 91, (2003); Osborne T.J., Linden N., Phys. Rev. A, 69, (2004); Christandl M., Datta N., Ekert A., Landahl A.J., Phys. Rev. Lett, 92, (2004); Mattis D.C., The Theory of Magnetism I, Solid State Science Series, 17, (1981); Tal-Ezer H., Kosloff R., J. Chem. Phys, 81, (1984); Leforestier C., Bisseling R.H., Cerjan C., Feit M.D., Friesner R., Guldberg A., Hammerich A., Jolicard G., Karrlein W., Meyer H.-D., Lipkin N., Roncero O., Kosloff R., J. Comput. Phys, 94, (1991); Iitaka T., Nomura S., Hirayama H., Zhao X., Aoyagi Y., Sugano T., Phys. Rev. E, 56, (1997); Dobrovitski V.V., De Raedt H.A., Phys. Rev. E, 67, (2003)","","","","","","","","","13474073","","JUPSA","","English","J. Phys. Soc. Jpn.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-33847322132" +"Schinckel A.P.; Mahan D.C.; Wiseman T.G.; Einstein M.E.","Schinckel, A.P. (7003328030); Mahan, D.C. (7006465023); Wiseman, T.G. (8554987900); Einstein, M.E. (7003294106)","7003328030; 7006465023; 8554987900; 7003294106","Impact of Alternative Energy Systems on the Estimated Feed Requirements of Pigs with Varying Lean and Fat Tissue Growth Rates When Fed Corn and Soybean Meal-Based Diets","2008","Professional Animal Scientist","24","3","","198","207","9","21","10.1532/S1080-7446(15)30841-X","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-75949127758&doi=10.1532%2fS1080-7446%2815%2930841-X&partnerID=40&md5=d028a9312fb770a6c986046bfe0f55d5","Department of Animal Sciences, Purdue University, West Lafayette, 47907-2054, IN, United States; The Ohio State University and Ohio Agricultural Research and Development Center, Columbus, 43210-1095, OH, United States","Schinckel A.P., Department of Animal Sciences, Purdue University, West Lafayette, 47907-2054, IN, United States; Mahan D.C., The Ohio State University and Ohio Agricultural Research and Development Center, Columbus, 43210-1095, OH, United States; Wiseman T.G., The Ohio State University and Ohio Agricultural Research and Development Center, Columbus, 43210-1095, OH, United States; Einstein M.E., Department of Animal Sciences, Purdue University, West Lafayette, 47907-2054, IN, United States","Swine growth models can be used to predict the nutrient requirements, feed costs, and economic returns of specific genetic populations of pigs. The objectives of this study were to 1) predict changes in energetic and economic efficiency of 2 genetic populations of pigs with different compositional growth rates; 2) compare the predictions of 3 energetic models - 2 ME based systems and a NE based system (ME-Noblet, ME-Tess, and NE), and 3) evaluate the impact of predicting maintenance energy requirements as a function of BW or lipid-free empty BW when fed corn-soybean meal based diets. The higher lean-gain (HLG) pigs had lesser rates of lipid deposition (423 vs. 356 g/d), greater protein deposition (101.89 vs. 106.0 g/d), and similar BW growth rates as the lesser lean-gain (LLG) pigs. Overall, the ME-Noblet and NE energy systems predicted similar feed intakes, diet composition, feed costs, and similar differences between the genetic populations and sexes. The HLG pigs were predicted to require 28.4, 29.9, and 30.1 kg less feed and to have 33.5, 34.1, and 29.1% greater lean efficiency (carcass lean-gain:feed intake) than the LLG pigs from 25 to 125 kg based on the ME-Noblet, NE, and ME-Tess equations, respectively. The prediction of maintenance requirements based on BW or lipid-free empty BW had little impact on the predicted differences between the 2 genetic populations. The 3 energy systems predicted similar differences in feed intakes and feed costs between the HLG and LLG pigs. © 2008 American Registry of Professional Animal Scientists.","Energy system; Growth model; Net energy; Pig","","","","","","","","Akridge J.T., Brorsen B.W., Whipker L.D., Forrest J.C., Kuei C.H., Schinckel A.P., Evaluation of alternative techniques to determine pork carcass value, J. Anim. Sci., 70, (1992); Birkett S., Lange K., Limitations of conventional models and a conceptual framework of a nutrient flow representation of energy utilization by animals, Br. J. Nutr., 86, (2001); Boys K.A., Li N., Preckel P.V., Schinckel A.P., Foster K.A., Economic replacement of a heterogeneous herd, Am. J. Agric. Econ., 89, (2007); de Lange C.F.M., Birkett S.H., Morel P.C.H., Protein, fat and bone tissue growth in Swine Nutrition, (2001); de Lange C.F.M., Marty B.J., Birkett S., Morel P., Szkotnicki B., Application of pig growth models in commercial pork production. Can, J. Anim. Sci., 81, (2001); de Lange C.F.M., Morel P.C.H., Birkett S.H., Modeling chemical and physical body composition of the growing pig, J.Anim. Sci., 81, (2003); Fuller M.F., McWilliam R., Wang T.C., Giles L.R., The optimum dietary amino acid pattern for growing pigs, Requirements for maintenance and for tissue protein accretion. Br. J. Nutr., 62, (1989); Gu Y., Schinckel A.P., Martin T.G., Growth, development, and carcass composition in five genotypes of swine, J. Anim. Sci., 70, pp. 1719-1729, (1992); Kitts K., Martin M.A., Preckel P.V., Schinckel A.P., Economic implications of alternative ractopamine dosages on hogs.Purdue Agric, Econ. Rep. West Lafa-yette, IN., 8, (1991); Koong L.J., Nienaber J.A., Pekas J.C., Yen J.T., Effects of plane of nutrition on organ size and fasting heat production in pigs, J. Nutr., 112, (1982); Moughan P.J., Kerr R.T., Smith W.C., The role of simulation models in the development of economically-optimal feeding regimens for the growing pig, Modeling Growth in the Pig, (1995); Noblet J., Karege C., Dubois S., Van Milgen J., Metabolic utilization of energy and maintenance requirements in growing pigs: Effects of sex and genotype, J. Anim. Sci., 77, (1999); Noblet J., van Milgen J., Energy value of pig feeds: Effect of pig body weight and energy evaluation system, J. Anim. Sci., 82, (2004); Nutrient requirements of swine, (1998); Pittroff W., Cartwright T.C., Modeling livestock systems, II. Understanding the relevant biology. Arch. Latinoam. Prod. Anim., 10, (2002); Quiniou N., Noblet J., Prediction of tissular body composition from protein and lipid deposition in growing pigs, J. Anim. Sci., 73, pp. 1567-1575, (1995); Sauvant D., Perez J.M., Tran G., Tables of Composition and Nutritional Value of Feed Materials: Pigs, Poultry, Cattle, Sheep, Goats, Rabbits, Horses, Fish, (2004); Schinckel A.P., Nutrient requirements of modern pig genotypes, Recent Ad-vances in Animal Nutrition, (1994); Schinckel A.P., Describing the pig, A Quantitative Biology of the Pig, (2003); Schinckel A.P., Li N., Richert B.T., Preckel P.V., Einstein M.E., Development of a model to describe the compositional growth and dietary lysine requirements of pigs fed ractopamine, J. Anim. Sci, 81, (2003); Schinckel A.P., Wagner J.R., Forrest J.C., Einstein M.E., Evaluation of alternative measures of pork carcass composition, J. Anim. Sci., 79, (2001); Schinckel A.P., Mahan D.C., Wiseman T.G., Einstein M.E., Growth of protein, moisture, lipid and ash of two genetic lines of barrows and gilts from twenty to one hundred twenty-five kilograms body weight, J. Anim. Sci., 86, (2008); Taylor S., Genetic size-scaling rules in animal growth, Anim. Prod., 30, (1980); Taylor S., Genetically standardized growth equations, Anim. Prod., 30, (1980); Tess M.W., Bennett G.L., Dickerson G.E., Simulation of genetic changes in life cycle efficiency of pork production. I. A Bioeconomic model, J. Anim. Sci., 56, (1983); Tess M.W., Bennett G.L., Dickerson G.E., Simulation of genetic changes in life cycle efficiency of pork production. II. Effects of components on efficiency, J. Anim. Sci., 56, (1995); Tess M.W., Bennett G.L., Dickerson G.E., Simulation of genetic changes in life cycle efficiency of pork production. III. Effects of management systems and feed prices on importance of genetic components, J. Anim. Sci., 56, (1983); Tess M.W., Dickerson G.E., Nienaber J.A., Yen J.T., Ferrell C.L., Energy costs of protein and fat deposition in pigs fed ad libitum, J. Anim. Sci., 58, (1984); van Milgen J., Bernier J.-F., Le Cozler Y., Dubois S., Noblet J., Major determinants of fasting heat production and energetic cost of activity in growing pigs of different body weight and breed/castration combina-tion, Br. J. Nutr., 79, (1998); Wagner J.R., Schinckel A.P., Chen W., Forrest J.C., Coe B.L., Analysis of body composition changes of swine during growth and development, J. Anim. Sci., 77, (1999); Whittemore C.T., The case for net energy and net protein models for performance prediction in pigs, Pig News and Information, 20, (1999); Wiseman T.G., Mahan D.C., Moeller S.J., Peters J.C., Fastinger N.D., Ching S., Kim Y.Y., Phenotypic measurements and various indices of lean and fat tissue development in barrows and gilts of two genetic lines from twenty to one hundred twenty-five kilograms of body weight, J. Anim. Sci., 85, (2007); Wiseman T.G., Mahan D.C., Peters J.C., Fastinger N.D., Ching S., Kim Y.Y., Tissue weights and body composition of 2 genetic lines of barrows and gilts from twenty to one hundred twenty-five kilograms of body weight, J. Anim. Sci., 85, (2007)","A.P. Schinckel; Department of Animal Sciences, Purdue University, West Lafayette, 47907-2054, United States; email: aschinck@purdue.edu","","Elsevier Inc.","","","","","","10807446","","","","English","Prof. Build. Sci.","Article","Final","","Scopus","2-s2.0-75949127758" +"Tan Xiaobo; Baras John S.; Krishnaprasad P.S.","Tan, Xiaobo (8664617000); Baras, John S. (7006833292); Krishnaprasad, P.S. (7005943029)","8664617000; 7006833292; 7005943029","Computational micromagnetics for magnetostrictive actuators","2000","Proceedings of SPIE - The International Society for Optical Engineering","3984","","","162","173","11","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033727235&partnerID=40&md5=8adaa6da904deae433551a98d8f7b8e8","Univ of Maryland, College Park, United States","Tan Xiaobo, Univ of Maryland, College Park, United States; Baras John S., Univ of Maryland, College Park, United States; Krishnaprasad P.S., Univ of Maryland, College Park, United States","Computational micromagnetics plays an important role in design and control of magnetostrictive actuators. A systematic approach to calculate magnetic dynamics and magnetostriction is presented. A finite difference method is developed to solve the coupled Landau-Lifshitz-Gilbert (LLG) equation for dynamics of magnetization and a one dimensional elastic motion equation. The effective field in the LLG equation consists of the external field, the demagnetizing field, the exchange field, and the anisotropy field. A hierarchical algorithm using multipole approximation speeds up the evaluation of the demagnetizing field, reducing computational cost from O(N2) to O(NlogN). A hybrid 3D/1D rod model is adopted to compute the magnetostriction: a 3D model is used in solving the LLG equation for the dynamics of magnetization; then assuming that the rod is along z-direction, we take all cells with same z-cordinate as a new cell. The values of the magnetization and the effective field of the new cell are obtained from averaging those of the original cells that the new cell contains. Each new cell is represented as a mass-spring in solving the motion equation. Numerical results include: 1. domain wall dynamics, including domain wall formation and motion; 2. effects of physical parameters, grid geometry, grid refinement and field step on H - M hysteresis curves; 3. magnetostriction curve.","","Actuators; Algorithms; Finite difference method; Magnetic domains; Magnetic hysteresis; Magnetization; Magnetostrictive devices; Domain wall dynamics; Magnetostrictive actuators; Micromagnetics; Magnetostriction","","","","","","","","","","Society of Photo-Optical Instrumentation Engineers","SPIE","Smart Structures and Materials 2000 - Mathematics and Control in Smart Structures","6 March 2000 through 9 March 2000","Newport Beach, CA, USA","57139","0277786X","","PSISD","","English","Proc SPIE Int Soc Opt Eng","Article","Final","","Scopus","2-s2.0-0033727235" +"Fukushima H.; Uesaka Y.; Nakatani Y.; Hayashi N.","Fukushima, H. (57214204552); Uesaka, Y. (35513921100); Nakatani, Y. (7202547641); Hayashi, N. (35352133200)","57214204552; 35513921100; 7202547641; 35352133200","Magnetization reversal below the Stoner-Wohlfarth field","2005","Journal of Magnetism and Magnetic Materials","290-291 PART 1","","","526","529","3","4","10.1016/j.jmmm.2004.11.518","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944345803&doi=10.1016%2fj.jmmm.2004.11.518&partnerID=40&md5=a22f25cd176ccab36bc4c91d8f38b1f5","3-73 Honda, Midori-ku, Chibaishi 266-0005, Japan; Nihon University, Kohriyama, 963-8642, Japan; University of Electro-Communications, Chofu, 182-0021, Japan","Fukushima H., 3-73 Honda, Midori-ku, Chibaishi 266-0005, Japan; Uesaka Y., Nihon University, Kohriyama, 963-8642, Japan; Nakatani Y., University of Electro-Communications, Chofu, 182-0021, Japan; Hayashi N., University of Electro-Communications, Chofu, 182-0021, Japan","A novel concept of the critical switching field for the magnetization reversal of a single-domain particle with small damping constant in a field at an oblique angle to the easy axis is proposed. It is derived from the locus of the magnetization plotted on the contour map of the potential. The critical field is defined as the field in which the potential at the initial point is the same as that at the saddle point of the potential. The influence of the coordinate system on the critical field is also presented. © 2004 Elsevier B.V. All rights reserved.","Magnetization reversal; Switching field; The Stoner-Wohlfarth field","Contour measurement; Damping; Differential equations; Energy dissipation; Magnetic anisotropy; Landau-Lifshitz-Gilbert (LLG) equation; Magnetization reversal; Switching field; The Stoner-Wohlfarth field; Magnetization","","","","","","","He L., Doyle W.D., Fujiwara H., IEEE Trans. Magn., 30, (1994); He L., Doyle W.D., Varga L., Fujiwara H., Flanders P.J., J. Magn. Magn. Mater., 155, (1996)","H. Fukushima; 3-73 Honda, Midori-ku, Chibaishi 266-0005, Japan; email: hcb00125@nifty.com","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-14944345803" +"Chen L.; Fernandez-de-Castro J.; Giusti J.; Fang H.; Hurben M.","Chen, Lujun (56111672300); Fernandez-de-Castro, Juan (7006216171); Giusti, Jim (6701602743); Fang, Hao (55470713200); Hurben, Michael (6602556423)","56111672300; 7006216171; 6701602743; 55470713200; 6602556423","Telegraph noise mechanism and LLG noise model","2000","IEEE Transactions on Magnetics","36","5 I","","3195","3198","3","6","10.1109/20.908735","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0034260834&doi=10.1109%2f20.908735&partnerID=40&md5=ee4ebccaddce571cc9989e56b97a24be","IEEE; Seagate Technology, Inc., Bloomington, MN 55435, United States","Chen L., Seagate Technology, Inc., Bloomington, MN 55435, United States; Fernandez-de-Castro J., Seagate Technology, Inc., Bloomington, MN 55435, United States; Giusti J., Seagate Technology, Inc., Bloomington, MN 55435, United States; Fang H., Seagate Technology, Inc., Bloomington, MN 55435, United States; Hurben M., IEEE, Seagate Technology, Inc., Bloomington, MN 55435, United States","A preliminary study on random telegraph noise (RTN) is made. RTN is defined as the magnetization states switching by thermal fluctuations. State jumping resulting in baseline shift from the media field could also be RTN-associated multi-states switching. Our analysis shows that the root cause of such magnetization multi-states could be due to: 1) free layer edge states switching caused by a weak PM field; 2) surface and/or interface roughness, especially the lapped air bearing surface (ABS); and 3) random defects in the stack layers. A thermal noise model with Landau-Lifshitz-Gilbert equation (LLG) was developed and was applied to RTN demonstration.","Baseline shift; GMR heads; Instability; Spin valve; Telegraph noise","Magnetic field effects; Magnetization; Mathematical models; Spurious signal noise; Switching; Telegraph; Thermal effects; Random telegraph noise (RTN); Magnetic recording","","","","","","","Zhu J.-G., O'Connor D.J., Impact of microstructure on stability of permanent magnet biased magnetoresistive heads, IEEE Trans. Magn., 32, pp. 54-60, (1996); Su J.L., Ju K., Track edge phenomena in thin longitudinal media, IEEE Trans. Magn., 25, (1989); Hsu Y., Spectrum analysis of base-LINE-popping noise in MR heads, IEEE Trans. Magn., 31, pp. 2636-2638, (1995); Baker B.R., Electrostatic popping in AMR and GMR heads, IEEE Trans. Magn., 35, pp. 2583-2585, (1999); Takano K.-I., Et al., Writer induced instability in spin-valve heads, IEEE Trans. Magn., 35, pp. 2589-2591, (1999); Kirschenbaum L.S., Rogers C.T., Telegraph noise in silver-permalloy giant magnetoresistance test structures, IEEE Trans. Magn., 31, pp. 3943-3945, (1995); Wallash A., A staudy of voltage fluctuation, noise and magnetic instability in spin valve GMR recording heads, IEEE Trans. Magn., 34, pp. 1450-1452, (1998); Hardner H.T., Hurben M.J., Tabat N., Noise and magnetic domain fluctuations in spin valve GMR heads, IEEE Trans. Magn., 35, pp. 2592-2594, (1999); Chen W., Et al., Energy barrier for thermal reversal of interacting particles, J. Appl. Phys., 7, pp. 5579-5584, (1992); Brown W.F., Thermal fluctuation of fine ferromagnetic particles, IEEE Trans. Magn., 15, pp. 1196-1208, (1979); Bertram H.N., Peng Q., Numerical simulations of the effect of record field pulse length on medium coercivity at finite temperature, IEEE Trans. Magn., 34, pp. 1543-1545, (1998); Boerner E.D., Bertram H.N., Non-arrhenius behavior in single domain particle, IEEE Trans. Magn., 34, pp. 1678-1680, (1998)","L. Chen; Seagate Technology, Inc., Bloomington, MN 55435, United States; email: Lujun_Chen@notes.seagate.com","","Institute of Electrical and Electronics Engineers Inc.","","2000 International Magnetics Conference (INTERMAG 2000)","9 April 2000 through 12 April 2000","Toronto, Ont","58080","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0034260834" +"Tan Xiaobo; Baras John S.; Krishnaprasad P.S.","Tan, Xiaobo (8664617000); Baras, John S. (7006833292); Krishnaprasad, P.S. (7005943029)","8664617000; 7006833292; 7005943029","Fast evaluation of demagnetizing field in three dimensional micromagnetics using multipole approximation","2000","Proceedings of SPIE - The International Society for Optical Engineering","3984","","","195","201","6","5","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033706215&partnerID=40&md5=41f926711480c614aade76b03381df07","Univ of Maryland, College Park, United States","Tan Xiaobo, Univ of Maryland, College Park, United States; Baras John S., Univ of Maryland, College Park, United States; Krishnaprasad P.S., Univ of Maryland, College Park, United States","Computational micromagnetics in three dimensions is of increasing interest with the development of magnetostrictive sensors and actuators. In solving the Landau-Lifshitz-Gilbert (LLG) equation, the governing equation of magnetic dynamics for ferromagnetic materials, we need to evaluate the effective field. The effective field consists of several terms, among which the demagnetizing field is of long-range nature. Evaluating the demagnetizing field directly requires work of O(N2) for a grid of N cells and thus it is the bottleneck in computational micromagnetics. A fast hierarchical algorithm using multipole approximation is developed to evaluate the demagnetizing field. We first construct a mesh hierarchy and divide the grid into boxes of different levels. The lowest level box is the whole grid while the highest level boxes are just cells. The approximate field contribution from the cells contained in a box is characterized by the box attributes, which are obtained via multipole approximation. The algorithm computes field contributions from remote cells using attributes of appropriate boxes containing those cells, and it computes contributions from adjacent cells directly. Numerical results have shown that the algorithm requires work of O(NlogN) and at the same time it achieves high accuracy. It makes micromagnetic simulation in three dimensions feasible.","","Actuators; Algorithms; Approximation theory; Computer simulation; Demagnetization; Numerical methods; Optical sensors; Three dimensional; Landau-Lifshitz-Gilbert equation; Magnetostrictive actuators; Magnetostrictive sensors; Micromagnetics; Multipole approximation; Magnetic fields","","","","","","","","","","Society of Photo-Optical Instrumentation Engineers","SPIE","Smart Structures and Materials 2000 - Mathematics and Control in Smart Structures","6 March 2000 through 9 March 2000","Newport Beach, CA, USA","57139","0277786X","","PSISD","","English","Proc SPIE Int Soc Opt Eng","Article","Final","","Scopus","2-s2.0-0033706215" +"Ming C.W.; David S.H.W.; Chen H.; Yan W.; Guo T.-T.","Ming, Chung Wang (7005683145); David, Shan Hill Wong (7401536178); Chen, Hongyuan (55743140000); Yan, Wei (59079295600); Guo, Tian-Min (7201788957)","7005683145; 7401536178; 55743140000; 59079295600; 7201788957","Homotopy continuation method for calculating critical loci of binary mixtures","1999","Chemical Engineering Science","54","17","","3873","3883","10","17","10.1016/S0009-2509(99)00020-2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033522768&doi=10.1016%2fS0009-2509%2899%2900020-2&partnerID=40&md5=7f06ac6fc0744b0419e896bb8a192c2f","Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30043, Taiwan; School of Chemical Engineering, University of Petroleum, Beijing 100083, 20 Xue Yuan Road, China","Ming C.W., Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30043, Taiwan; David S.H.W., Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30043, Taiwan; Chen H., School of Chemical Engineering, University of Petroleum, Beijing 100083, 20 Xue Yuan Road, China; Yan W., School of Chemical Engineering, University of Petroleum, Beijing 100083, 20 Xue Yuan Road, China; Guo T.-T., School of Chemical Engineering, University of Petroleum, Beijing 100083, 20 Xue Yuan Road, China","This work describes an algorithm that uses the Heidemann and Khalil (1980, A.I.Ch.E.J., 26, 769-779) critical point criteria and a homotopy continuation technique for calculating critical loci in binary mixtures. This approach is able to track smoothly transition from G/L critical points to L/L critical points without the need of changing initial estimates. Such transitions marked by the existence of a turning point in the critical locus are commonly found in type III and IV mixtures. The tangent plane global stability tests are included to locate UCEPs and LCEPs which are intersections of the critical locus and the LLG line. The continuation method is as efficient as a gradient-based approach like Heidemann and Khalil's method and as robust as the Hicks and Young's grid-search approach. It also provides physical insight to the change in phase behavior as the composition and the equation of states parameters change.; This work describes an algorithm that uses the Heidemann and Khalil (1980, A.I.Ch.E.J., 26, 769-779) critical point criteria and a homotopy continuation technique for calculating critical loci in binary mixtures. This approach is able to track smoothly transition from G/L critical points to L/L critical points without the need of changing initial estimates. Such transitions marked by the existence of a turning point in the critical locus are commonly found in type III and IV mixtures. The tangent plane global stability tests are included to locate UCEPs and LCEPs which are intersections of the critical locus and the LLG line. The continuation method is as efficient as a gradient-based approach like Heidemann and Khalil's method and as robust as the Hicks and Young's grid-search approach. It also provides physical insight to the change in phase behavior as the composition and the equation of states parameters change.","Binary mixture; Critical loci; Equations of state; Global phase diagram; Global stability; Homotopy continuation method","binary mixture; critical point; equation of state; stability; Asymptotic stability; Equations of state; Numerical methods; Phase diagrams; Phase transitions; Pressure; Temperature; Critical loci; Global phase diagram; Global stability; Homotopy continuation method; Binary mixtures","","","","","National Natural Science Foundation of China, NSFC; National Science Council, NSC, (NSC 88-2216-E-007-015); National Science Council, NSC","This work is supported partly by National Science Council of Taiwan through grant NSC 88-2216-E-007-015. D.S.H. Wong would like to thank the National Science Foundation of China and K.T. Li Foundation of Taiwan for supporting his visit to Beijing. Yan Wei would like to thank the K.T. Li Foundation of Taiwan for supporting his visit to Hsinchu.","Boshkov L.Z., Description of the phase diagram of two-component solutions with a closed loop region of phase separation on the basis of a one-fluid model of the equation of state, Doklady Akademii. Nauk SSSR, 294, pp. 901-905, (1987); Castier M., Sandler S.I., Critical points with the Wong-Sandler mixing rule-I. Calculations with the van der Waals equation of state, Chemical Engineering Science, 52, pp. 3393-3399, (1997); DeGance A.E., Ab initio equation of state equilibria computations via path continuation, Fluid Phase Equilibria, 89, pp. 303-334, (1993); Doedel E.J., Wang X.J., Fairgrieve T.F., AUTO94 - Software for Continuation and Bifurcation Problems in Ordinary Differential Equations, (1995); Heidemann R.A., Khalil A.M., The calculation of critical points, The American Institute of Chemical Engineers Journal, 26, pp. 769-779, (1980); Hicks C.P., Young C.L., Theoretical prediction of phase behaviour at high temperatures and pressures for non-polar mixtures. Part 1.-Computer solution techniques and stability tests, Journal of the Chemical Society, Faraday Transactions II, 73, pp. 597-612, (1977); Keller H.B., Lectures on Numerical Methods in Bifurcation Problems, (1987); Kolar P., Kojima K., Prediction of critical multicomponent systems using the PSRK group contribution equation of state, Fluid Phase Equilibria, 118, pp. 175-200, (1996); Lin W.J., Seader J.D., Computing multiple solutions to systems of interlinked separation columns, The American Institute of Chemical Engineers Journal, 33, pp. 886-897, (1987); Michelsen M.L., The isothermal flash problem. Part 1. Stability analysis, Fluid Phase Equilibria, 9, pp. 1-19, (1982); Reid R.C., Beegle B.L., Critical point criteria in Legendre transform notation, The American Institute of Chemical Engineers Journal, 23, pp. 726-732, (1977); Riggs J.B., An Introduction to Numerical Methods for Chemical Engineers (2nd Ed.), (1994); Rowlinson J.S., Swinton F.L., Liquids and Liquid Mixtures, (1982); Sadus R.J., High Pressure Phase Behaviour of Multicomponent Fluid Mixtures, (1992); Sadus R.J., Calculation critical transitions of fluid mixtures: Theory vs. experiment, The American Institute of Chemical Engineers Journal, 40, pp. 1376-1403, (1994); Stockfleth R., Dohrn R., An algorithm for calculating critical points in multicomponent mixtures which can easily be implemented in existing programs to calculate phase equilibria, Fluid Phase Equilibria, 145, pp. 43-52, (1998); Sun A.C., Seider W.D., Homotopy-continuation method for stability analysis in the global minimization of Gibbs free energy, Fluid Phase Equilibria, 103, pp. 213-249, (1995); Van Konynenburg P.H., Scott R.L., Critical lines and phase equilibria in binary van der Waals mixtures, Philosophical Transactions of the Royal Society of London A, 298, pp. 495-540, (1980); Van Pelt A., Peters C.J., De Swaan Arons J., Liquid-liquid immiscibility loops predicted with the simplified-perturbed-hard-chain theory, Journal of Chemical Physics, 95, pp. 7569-7575, (1991); Van Pelt A., De Loos Th.W., Connectivity of critical lines around the van Laar point in T, X projection, Journal of Chemical Physics, 97, pp. 1271-1281, (1992); Van Pelt A., Peters C.J., De Swaan Arons J., Calculation of critical lines in binary mixtures with the simplified-perturbed-hard-chain theory, Fluid Phase Equilibria, 84, pp. 23-47, (1993); Wayburn T.L., Seader J.D., Homotopy continuation methods for computer-aided process design, Computer Chemical Engineering, 11, pp. 7-25, (1987)","D.S.H. Wong; Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30043, Taiwan; email: dshwong@che.nthu.edu.tw","","Elsevier Science Ltd","","","","","","00092509","","CESCA","","English","Chem. Eng. Sci.","Article","Final","","Scopus","2-s2.0-0033522768" +"Tamaru S.; Bain J.A.; Van De Veerdonk R.J.M.; Crawford T.M.; Covington M.; Kryder M.H.","Tamaru, S. (7003518136); Bain, J.A. (26643572500); Van De Veerdonk, R.J.M. (6603914196); Crawford, T.M. (7102138487); Covington, M. (7005536523); Kryder, M.H. (35576586200)","7003518136; 26643572500; 6603914196; 7102138487; 7005536523; 35576586200","Measurement of magnetostatic mode excitation and relaxation in permalloy films using scanning Kerr imaging","2004","Physical Review B - Condensed Matter and Materials Physics","70","10","104416","104416","1","-104415","42","10.1103/PhysRevB.70.104416","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-19744382132&doi=10.1103%2fPhysRevB.70.104416&partnerID=40&md5=3afb887062e1c5afb92134d618a3c632","Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA 15213, United States; Seagate Research, Pittsburgh, PA 15222, United States","Tamaru S., Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA 15213, United States; Bain J.A., Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA 15213, United States; Van De Veerdonk R.J.M., Seagate Research, Pittsburgh, PA 15222, United States; Crawford T.M., Seagate Research, Pittsburgh, PA 15222, United States; Covington M., Seagate Research, Pittsburgh, PA 15222, United States; Kryder M.H., Seagate Research, Pittsburgh, PA 15222, United States","This work presents experimental results of magnetostatic mode excitation using scanning Kerr microscopy under continuous sinusoidal excitation in the microwave frequency range. This technique was applied to 100 nm thick permalloy coupons excited in two different ways. In the first experiment, the uniform (Kittel) mode was excited at frequencies in 2.24-8.00 GHz. The resonant condition was effectively described with the conventional Kittel mode equation. The LLG damping parameter a increased significantly with decreasing bias field. It was confirmed that this increase was caused by multidomain structure and ripple domains formed under weak bias fields, as suggested by other studies. In the second experiment, propagating magnetostatic mode surface waves were excited. They showed an exponential amplitude decay and a linear phase variation with distance from the drive field source, consistent with a decaying plane wave. The Damon-Eshbach (DE) model was extended to include a finite energy damping and used to analyze the results. It was found that the wave number and the decay constant were reasonably well described by the extended DE model. In contrast to the first experiment, no significant variation of α with frequency or bias field was seen in this second experiment, where spatial inhomogeneities in the magnetization are less significant.","","alloy; permalloy; transition element; unclassified drug; analytic method; article; data analysis; device; dynamics; film; imaging system; magnetic field; measurement; microwave radiation; radioisotope decay; scanning kerr system; technique","","","","","National Science Foundation, NSF, (ECD-8907068); National Science Foundation, NSF","The author would like to thank Josh Schare for the finite element method calculation of the bias field distribution and Seungook Min for preliminary sample fabrication. This work was supported, in part, by the National Science Foundation under Grant No. ECD-8907068.","Chikazumi S., Physics of Ferromagnetism, 2nd Ed., (1997); Patton C.E., Frait A., Wilts C.H., J. Appl. Phys., 46, (1975); Bastian D., Biller E., Phys. Status Solidi A, 35, (1976); Mizukami S., Ando Y., Miyazaki T., Jpn. J. Appl. Phys., Part 1, 40, (2001); Doyle W.D., He X., Tang P., Jagielinski T., Smith N., J. Appl. Phys., 73, (1993); Klemmer T.J., Ellis K.A., Van Dover B., J. Appl. Phys., 87, (2000); Jayasekara W.P., Bain J.A., Kryder M.H., IEEE Trans. Magn., 34, (1998); Silva T.J., Lee C.S., Crawford T.M., Rogers C.T., J. Appl. Phys., 85, (1999); Sandler G.M., Bertram H.N., Silva T.J., Crawford T.M., J. Appl. Phys., 85, (1999); Silva T.J., Crawford T.M., IEEE Trans. Magn., 35, (1999); Crawford T.M., Covington M., Parker G.J., Phys. Rev. B, 67, (2003); Hiebert W.K., Stankiewicz A., Freeman M.R., Phys. Rev. Lett., 79, (1997); Salansky N.M., Khrustalev B.P., Melnik A.S., Salanskaya L.A., Sinegubova Z.I., Thin Solid Films, 4, (1969); Covington M., Crawford T.M., Parker G.J., Phys. Rev. Lett., 89, (2002); Damon R.W., Eshbach J.R., J. Phys. Chem. Solids, 19, (1961); Bailleul M., Olligs D., Fermon C., Demokritov S.O., Europhys. Lett., 56, (2001); Hiebert W.K., Ballentine G.E., Freeman M.R., Phys. Rev. B, 65, (2002); Park J.P., Eames P., Engebretson D.M., Crowell P.A., Phys. Rev. Lett., 89, (2002); Tamaru S., Bain J.A., Van De Veerdonk R., Crawford T.M., Covington M., Kryder M.H., J. Appl. Phys., 91, (2002); Briant P.H., Smyth J.F., Schultz S., Fredkin D.R., Phys. Rev. B, 47, (1993); Craik D.J., Magnetic Oxides Part 2, (1975); Chen C.-W., Magnetism and Metallurgy of Soft Magnetic Materials, (1986); Stancil D.D., Theory of Magnetostatic Waves, (1993); Silva T.J., Pufall M.R., Kabos P., J. Appl. Phys., 91, (2002); Almeida N.S., Mills D.L., Phys. Rev. B, 53, (1996); Heinrich B., Urban R., Woltersdolf G., IEEE Trans. Magn., 38, (2002); McMichael R.D., Kunz A., J. Appl. Phys., 91, (2002); Ingvarsson S., Ritchie L., Liu X.Y., Xiao G., Slonczewski J.C., Trouilloud P.L., Koch R.H., Phys. Rev. B, 66, (2002); Kunes J., Kamabersky V., Phys. Rev. B, 65, (2002)","S. Tamaru; Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, PA 15213, United States; email: stamaru@andrew.cmu.edu","","American Physical Society","","","","","","01631829","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","","Scopus","2-s2.0-19744382132" +"Hayashi N.; Nakatani Y.; Uesaka Y.","Hayashi, Nobuo (35352133200); Nakatani, Yoshinobu (7202547641); Uesaka, Yasutaro (35513921100)","35352133200; 7202547641; 35513921100","Accuracy of the backward-difference solution of the Landau-Lifshitz-Gilbert equation","2003","Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers","42","3","","1250","1257","7","3","10.1143/jjap.42.1250","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0037615206&doi=10.1143%2fjjap.42.1250&partnerID=40&md5=ee3d73d8f14878e8fd86f487656caf47","University of Electro-Communications, Chofu, Tokyo 182-8585, Japan; Nihon University, Koriyama, Fukushima 963-8642, Japan","Hayashi N., University of Electro-Communications, Chofu, Tokyo 182-8585, Japan; Nakatani Y., University of Electro-Communications, Chofu, Tokyo 182-8585, Japan; Uesaka Y., Nihon University, Koriyama, Fukushima 963-8642, Japan","The reason for the low time-step accuracy of the previously developed approximate backward-difference solution of the Landau-Lifshitz-Gilbert (LLG) equation was found, and improved methods were developed. The improvement was carried out in two steps: correction of the expansion coefficients for the first-order backward-difference treatment of magnetization, and extension of the corrected scheme to a strict Crank-Nicolson scheme based on Newton's iteration. The time-step dependence of the velocity of a Bloch wall in planar- and perpendicular-magnetization films and the switching time of a fine iron-oxide particle were calculated to examine the time-step accuracy of the derived programs. The time-step dependence decreased considerably in the solutions obtained by the corrected program except for the Bloch wall motion in a perpendicular-magnetization film. However, it was removed almost entirely in the solutions obtained by the Crank-Nicolson method in which Newton's iteration was repeated twice per time step.","Backward-difference method; Crank-Nicolson method; Ferromagnetic particle; Landau-Lifshitz-Gilbert equation; Magnetization reversal; Micromagnetics","Costs; Damping; Iterative methods; Linear equations; Magnetization; Velocity; Backward-difference solutions; Magnetic films","","","","","","","Nakatani Y., Hayashi N., Uesaka Y., Jpn. J. Appl. Phys., 28, (1989); Shir C.C., J. Appl. Phys., 49, (1978); Young D.M., Gregory R.T., A Survey of Numerical Mathematics, 2, (1973); Peressini A.L., Sullivan F.E., Uhl J.J. Jr., The Mathematics of Nonlinear Programming, (1980); Mizukura T., Hayashi N., J. Magn. Soc. Jpn., 17, (1993); Hayashi N., Nakatani Y., Awano H., Ohta H., Inaba N., J. Magn. Soc. Jpn., 23, (1999); Chikazumi S., Physics of Ferromagnetism, (1997); Uesaka Y., Endo H., Takahashi T., Nakatani Y., Hayashi N., Fukushima H., Phys. Status Solidi A, 189, (2002)","","","Japan Society of Applied Physics","","","","","","00214922","","JAPND","","English","Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap","Article","Final","","Scopus","2-s2.0-0037615206" +"Serpico C.; D'Aquino M.; Bertotti G.; Mayergoyz I.D.","Serpico, Claudio (23013514800); D'Aquino, Massimiliano (9732823500); Bertotti, Giorgio (7005370974); Mayergoyz, Isaak D. (35495971500)","23013514800; 9732823500; 7005370974; 35495971500","Quasiperiodic magnetization dynamics in uniformly magnetized particles and films","2004","Journal of Applied Physics","95","11 II","","7052","7054","2","23","10.1063/1.1689211","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-2942670419&doi=10.1063%2f1.1689211&partnerID=40&md5=0c12d84fbad3225b42386a3c23f2fa93","Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; IEN, Galileo Ferraris, 911-10135 Torino, Strada delle Cacce, Italy; Department of Electrical Engineering, University of Maryland, College Park, MD 20742, United States","Serpico C., Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; D'Aquino M., Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; Bertotti G., IEN, Galileo Ferraris, 911-10135 Torino, Strada delle Cacce, Italy; Mayergoyz I.D., Department of Electrical Engineering, University of Maryland, College Park, MD 20742, United States","The Landau-Lifshitz-Gilbert (LLG) magnetization dynamics was investigated in uniaxial particles and films subject to circularly polarized electromagnetic fields. A perturbation technique was applied to predict the existence, the number, shape, and the stability of the limit cycles for small value of the damping constant in the LLG equation. The analysis was carried out by using an appropriate perturbation technique which is generally referred to as Poincaré-Melnikov function technique. The results show that it is possible to study the problem in an appropriate rotating reference frame where the applied field does not explicitly depend on time.","","Anisotropy; Chaos theory; Damping; Differential equations; Electromagnetic fields; Hamiltonians; Perturbation techniques; Time varying systems; Chaotic dynamics; Damping constant; Landau-Lifshitz-Gilbert equation; Magnetized particles; Magnetization","","","","","","","Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, (2001); Lichtenberg A.J., Lieberman M.A., Regular and Chaotic Dynamics, (1992); Perko L., Differential Equations and Dynamical Systems, (1996)","C. Serpico; Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; email: serpico@unina.it","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-2942670419" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, G. (7005370974); Mayergoyz, I.D. (35495971500); Serpico, C. (23013514800)","7005370974; 35495971500; 23013514800","Perturbation technique for LLG equation","2002","INTERMAG Europe 2002 - IEEE International Magnetics Conference","","","1001021","","","","0","10.1109/INTMAG.2002.1001021","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85017265740&doi=10.1109%2fINTMAG.2002.1001021&partnerID=40&md5=c4cdd6e7da3537a950a67539d94f92d7","Istituto Elettrotecnico Nazionale (IEN), Galileo Ferraris, Strada delle Cacce 91, Torino, I-10135, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States; Dipartimento di Ingegneria Elettrica, Università di Napoli Federico II, Via Claudio 21, Napoli, I-80125, Italy","Bertotti G., Istituto Elettrotecnico Nazionale (IEN), Galileo Ferraris, Strada delle Cacce 91, Torino, I-10135, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States; Serpico C., Dipartimento di Ingegneria Elettrica, Università di Napoli Federico II, Via Claudio 21, Napoli, I-80125, Italy","Recently, analytical solutions of Landau-Lifshitz-Gilbert (LLG) equation for isotropic media and circularly polarized applied radio-frequency (RF) fields have been reported. These analytical solutions can be derived by using the rotational invariance of the system with respect to rotations around the symmetry axis. In fact, the presence of rotational symmetry permits one to reduce the problem to the study of an autonomous dynamical system on the sphere, amenable to an exact analytical treatment. The purpose of this paper is to extend this analytical solutions to the case of anisotropic media and elliptically polarized applied RF fields. This is accomplished by treating anisotropic media and elliptically polarized fields as perturbations of isotropic media and circularly polarized fields, respectively. ©2002 IEEE.","","Anisotropy; Circular polarization; Dynamical systems; Perturbation techniques; Analytical treatment; Autonomous dynamical systems; Circularly polarized; Elliptically polarized field; Landau-Lifshitz-Gilbert equations; Radio frequency fields; Rotational invariances; Rotational symmetries; Anisotropic media","","","","","","","Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, 6, (2001); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 89, 11, (2001)","","Fidler J.; Hillebrands B.; Ross C.; Weller D.; Folks L.; Hill E.; Vazquez Villalabeitia M.; Bain J.A.; De Boeck J.; Wood R.","Institute of Electrical and Electronics Engineers Inc.","","2002 IEEE International Magnetics Conference, INTERMAG Europe 2002","28 April 2002 through 2 May 2002","Amsterdam","116193","","0780373650; 978-078037365-5","","","English","INTERMAG Europe - IEEE Int. Magn. Conf.","Conference paper","Final","","Scopus","2-s2.0-85017265740" +"Wieser R.; Nowak U.; Usadel K.D.","Wieser, R. (7005738650); Nowak, U. (7003770249); Usadel, K.D. (7102136162)","7005738650; 7003770249; 7102136162","Domain wall motion in nanowires","2005","Phase Transitions","78","1-3","","115","120","5","5","10.1080/01411590412331316663","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-12344280933&doi=10.1080%2f01411590412331316663&partnerID=40&md5=e67b12443aee1df4c978d30f15904908","Institute of Physics, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany","Wieser R., Institute of Physics, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany; Nowak U., Institute of Physics, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany; Usadel K.D., Institute of Physics, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany","We investigated the motion of domain walls in ferromagnetic cylindrical nanowires by solving the Landau-Lifshitz-Gilbert equation numerically for a classical spin model in which energy contributions from exchange, crystalline anisotropy, dipole-dipole interactions, and a driving magnetic field are considered. Depending on the diameter, either transverse domain walls or vortex walls are found. A transverse domain wall is observed for diameters smaller than the exchange length of the given system. In this case, the system effectively behaves one dimensionally and the domain wall velocity agrees with the result of Slonczewski for one-dimensional walls. For larger diameters, a crossover to a vortex wall sets in which enhances the domain wall velocity drastically. For a vortex wall the domain wall velocity is described by the Walker formula.","Classical spin model; Domain wall motion; Langevin dynamics; LLG","Anisotropy; Computer simulation; Crystalline materials; Ferromagnetism; Magnetic fields; Magnetization; Mathematical models; Velocity measurement; Classical spin models; Domain wall motion; Landau-Lifshitz-Gilbert (LLG) equation; Langevin dynamics; Nanowires; Nanostructured materials","","","","","Deutsche Forschungsgemeinschaft, DFG, (SFB 491)","We acknowledge the support by the Deutsche Forschungsgemeinschaft (SFB 491).","Ross C.A., Chantrell R.W., Hwang M., Farhoud M., Et al., Incoherent magnetization reversal in 30 nm Ni particles, Phys. Rev. B, 62, (2000); Nielsch K., Wehrspohn R.B., Barthel J., Kirschner J., Et al., High density hexagonal nickel nanowire array, J. Magn. Magn. Mater., 249, (2002); Ono T., Miyajima H., Shigeto K., Mibu K., Et al., Propagation of a magnetic domain wall in a submicron magnetic wire, Science, 284, (1999); Landau D.L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, (1935); Dillon J.F., Magnetism, 1, (1963); Schryer N.L., Walker L.R., The motion of 180° domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, (1974); Malozemoff A.P., Slonczewski J.C., Magnetic Domain Walls in Bubble Materials, (1979); Garanin D.A., Dynamics of elliptic domain walls, Physica A, 178, (1991); Nowak U., Thermally activated reversal in magnetic nanostructures, Annual Reviews of Computational Physics IX, (2001); Forster H., Schrefl T., Suess D., Scholz W., Et al., Domain wall motion in nano-wires using moving grids, J. Appl. Phys., 91, (2002); Hertel R., Kirschner J., Magnetization reversal dynamics in nickel nanowires, Physica B, 343, (2004); Wieser R., Nowak U., Usadel K.D., Domain wall mobility in nanowires: Transverse vs. vortex walls, Phys. Rev. B, 69, (2004)","R. Wieser; Institute of Physics, University of Duisburg-Essen, Duisburg Campus, 47048 Duisburg, Germany; email: robert@thp.uni-duisburg.de","","","","","","","","01411594","","PHTRD","","English","Phase Transitions","Conference paper","Final","All Open Access; Green Open Access","Scopus","2-s2.0-12344280933" +"Shiiki K.; Hori H.","Shiiki, Kazuo (7006734250); Hori, Hironobu (8287343200)","7006734250; 8287343200","Micro-magnetic simulation of high-frequency magnetization process","2005","Journal of Magnetism and Magnetic Materials","290-291 PART 1","","","456","459","3","2","10.1016/j.jmmm.2004.11.234","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944374002&doi=10.1016%2fj.jmmm.2004.11.234&partnerID=40&md5=2c7c76b62de7f2308cfad5fe969e0ceb","Dept. of Appl. Phys. and Phys.-Info., Keio University, Yokohama 223-8522, Japan; Dept. of Appl. Phys. and Phys.-Info., Faculty of Science and Technology, Keio University, Yokohama, Kanagawa 223-8522, 3-14-1, Hiyoshi, Japan","Shiiki K., Dept. of Appl. Phys. and Phys.-Info., Keio University, Yokohama 223-8522, Japan, Dept. of Appl. Phys. and Phys.-Info., Faculty of Science and Technology, Keio University, Yokohama, Kanagawa 223-8522, 3-14-1, Hiyoshi, Japan; Hori H., Dept. of Appl. Phys. and Phys.-Info., Keio University, Yokohama 223-8522, Japan","A new micro-magnetic simulation method based on the Landau-Lifshitz-Gilbert (LLG) equation and including eddy current effects is presented. Real-time simulations in high-frequency fields up to 1 GHz are performed, and the magnetization under dynamic effective magnetic fields is obtained by solving the LLG equation of motion. The effective field is expressed as the sum of the external field, anisotropic field, demagnetization field, and exchange field, which are already considered in the conventional method, as well as the eddy current field. Using Biot-Savart's law, the eddy current field is calculated from the eddy current induced by a change in magnetization, and it is clarified that the response of the magnetization is delayed due to natural resonance and the eddy current. © 2004 Elsevier B.V. All rights reserved.","Eddy currents; Magnetization processes; Micromagnetic calculation; Resonance","Computer simulation; Eddy currents; Electric conductivity; Equations of motion; Magnetic anisotropy; Magnetic fields; Real time systems; Soft magnetic materials; Anisotropic magnetic fields; Eddy current fields; Magnetization processes; Micromagnetic simulations; Magnetization","","","","","","","Qingzhi P., Bertram H.N., IEEE Trans. Magn., 33, (1997); Klaassen K.R., Hirko R.G., Contreras J.T., IEEE Trans. Magn., 34, (1998); Haseba Y., Nagamine S., Shiiki K., IEEE Trans. Magn., 35, (1999); Torre E.D., Eicke J.G., IEEE Trans. Magn., 33, (1997); Shir C.C., J. Appl. Phys., 28, (1989); Shiiki K., Mitsui Y., J. Appl. Phys., 75, (1994)","K. Shiiki; Dept. of Appl. Phys. and Phys.-Info., Faculty of Science and Technology, Keio University, Yokohama, Kanagawa 223-8522, 3-14-1, Hiyoshi, Japan; email: shiiki@appi.keio.ac.jp","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-14944374002" +"Valcu B.; Bertram H.N.","Valcu, Bogdan (6602240038); Bertram, H. Neal (55663721400)","6602240038; 55663721400","Soft underlayer magnetization dynamics","2004","IEEE Transactions on Magnetics","40","4 II","","2377","2379","2","1","10.1109/TMAG.2004.832671","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-4444265780&doi=10.1109%2fTMAG.2004.832671&partnerID=40&md5=5b65285a9a56e13a58a730155a8b8e62","Ctr. for Magnetic Recording Research, Univ. of California at San Diego, San Diego, CA 92093-0401, United States","Valcu B., Ctr. for Magnetic Recording Research, Univ. of California at San Diego, San Diego, CA 92093-0401, United States; Bertram H.N., Ctr. for Magnetic Recording Research, Univ. of California at San Diego, San Diego, CA 92093-0401, United States","A micromagnetic model for the writing process in perpendicular magnetic recording is developed to study the effect of the soft underlayer on the dynamic reversal of the recording layer. The upper part of the soft material is discretized micromagnetically, each spin following LLG dynamics; the remaining part has infinite permeability. The validity of the model is tested in the static case. Dynamically, high-frequency spin motion is observed in the soft layer. Nevertheless, the field inside the data layer follows the time dependence of the input waveform.","LLG equation; Perpendicular recording; Soft underlayer","Damping; Gyroscopes; Magnetic fields; Magnetic flux; Magnetic permeability; Magnetic recording; Mathematical models; Oscillations; Waveform analysis; LLG equation; Perpendicular recording; Single pole head (SPH); Soft underlayer; Magnetization","","","","","INSIC-EHDR","Manuscript received October 15, 2003. This work was supported by a grant from INSIC-EHDR. The authors are with the Center for Magnetic Recording Research, University of California at San Diego, La Jolla, CA 92093-0401 USA (e-mail: bvalcu@ physics.ucsd.edu; nbertram@ucsd.edu). Digital Object Identifier 10.1109/TMAG.2004.832671","Schrefl T., Schabes M.E., Lengsfield B., Fast reversal dynamics in perpendicular magnetic recording media with soft underlayer, J. Appl. Phys., 91, pp. 8662-8665, (2002); Bertram H.N., Williams M., SNR and density limit estimates: A comparison of longitudinal and perpendicular recording, IEEE Trans. Magn., 36, pp. 4-9, (2000); Gao K.Z., Bertram H.N., Magnetic recording configuration for densities beyond 1 Tb/in2 and data rates beyond l Gb/s, IEEE Trans Magn., 38, pp. 3675-3683, (2002); Wang X., Bertram H.N., Anomalously large damping in magnetization reversal, J. Appl. Phys., 93, pp. 7396-7398, (2003); Ju G., Et al., High frequency dynamics of the soft underlayer in perpendicular recording system, J. Appl. Phys., 91, pp. 8052-8054, (2002)","B. Valcu; Ctr. for Magnetic Recording Research, Univ. of California at San Diego, San Diego, CA 92093-0401, United States; email: bvalcu@physics.ucsd.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-4444265780" +"Ciubotaru F.; Stancu A.; Stoleriu L.","Ciubotaru, F. (9734943500); Stancu, A. (14037953900); Stoleriu, L. (6603682281)","9734943500; 14037953900; 6603682281","LLG study of the precessional switching process in pulsed magnetic fields","2004","Journal of Optoelectronics and Advanced Materials","6","3","","1017","1021","4","5","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-5044221730&partnerID=40&md5=0797eb958158cd9b35448b790e54cad9","Alexandra Ioan Cuza University, Faculty of Physics, Department of Electricity, Iasi, 700506, 11, Blvd. Carol I, Romania","Ciubotaru F., Alexandra Ioan Cuza University, Faculty of Physics, Department of Electricity, Iasi, 700506, 11, Blvd. Carol I, Romania; Stancu A., Alexandra Ioan Cuza University, Faculty of Physics, Department of Electricity, Iasi, 700506, 11, Blvd. Carol I, Romania; Stoleriu L., Alexandra Ioan Cuza University, Faculty of Physics, Department of Electricity, Iasi, 700506, 11, Blvd. Carol I, Romania","In this paper we are presenting the results of our micromagnetic studies concerning the precessional switching process of the magnetic moment in the presence of a pulsed magnetic field. The magnetization dynamic is calculated with the well-known Landau-Lifshitz-Gilbert equation. We have analyzed the effect of pulse duration and the effects induced by the moment orientation dependent damping term. The results are discussed and compared with the results presented by other authors.","Landau-Lifshitz-Gilbert equation; Magnetization switching; Single domain particle","Computer simulation; Free energy; Magnetic moments; Magnetic recording; Magnetization; Numerical analysis; Probability; Relaxation processes; Switching; Thin films; Landau-Lifshitz-Gilbert equation; Magnetization switching; Nanomagnetism; Single domain particle; Magnetic materials","","","","","","","Gerrits Th., Van Den Berg H.A.M., Hohlfeld J., Bar L., Rasing Th., Nature, 418, (2002); Schumacher H.W., Chappert C., Crozat P., Sousa R.C., Freitas P.P., Miltat J., Fassbender J., Hillebrands B., Phys. Rev. Lett., 90, 1, (2003); Schumacher H.W., Chappert C., Sousa R.C., Freitas P.P., Miltat J., Phys. Rev. Lett., 90, 1, (2003); Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002); Russek S.E., Kaka S., Donahue M.J., J. Appl. Phys., 87, (2000); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, 5, (2000); Hiebert W.K., Ballentine G.E., Freeman M.R., Phys. Rev. B, 65, (2002); Hiebert W.K., Lagae L., De Boeck J., Phys. Rev. B., 68, (2003); Acremann Y., Back C.H., Buess M., Portmann O., Vaterlaus A., Pescia D., Melchior H., Science, 290, (2000); Hillebrands B., Ounadjela K., Spin Dynamics in Confined Magnetic Structures, 1-2, (2001); Bertoti G., Mayergoyz I.D., Serpico C., IEEE Trans. Magn., 39, 5, (2003); Stancu A., Spinu L., Optoelectron J., Adv. Mater., 1, (2003); Bertoti G., Mayergoyz I.D., Serpico C., D'Aquino M., IEEE Trans. Magn., 39, 5, (2003)","A. Stancu; Alexandra Ioan Cuza University, Faculty of Physics, Department of Electricity, Iasi, 700506, 11, Blvd. Carol I, Romania; email: alstancu@uaic.ro","","","","","","","","14544164","","","","English","J. Optoelectron. Adv. Mat.","Conference paper","Final","","Scopus","2-s2.0-5044221730" +"Usov N.A.; Peschany S.E.","Usov, N.A. (35586942300); Peschany, S.E. (6507933772)","35586942300; 6507933772","Theoretical hysteresis loops for single-domain particles with cubic anisotropy","1997","Journal of Magnetism and Magnetic Materials","174","3","","247","260","13","52","10.1016/S0304-8853(97)00180-7","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0031549501&doi=10.1016%2fS0304-8853%2897%2900180-7&partnerID=40&md5=da4db7f387dc8255dc733ce671d94185","Troitsk Inst. Innov. and Fusion Res., TRINITI, 142092, Troitsk, Russian Federation","Usov N.A., Troitsk Inst. Innov. and Fusion Res., TRINITI, 142092, Troitsk, Russian Federation; Peschany S.E., Troitsk Inst. Innov. and Fusion Res., TRINITI, 142092, Troitsk, Russian Federation","The magnetic properties of randomly oriented assembly of noninteracting single-domain particles with cubic anisotropy are studied in detail. Both signs of the cubic anisotropy constant are considered. We analyze the irreversible jumps of particle magnetization by means of direct solution of the Landau-Lifshitz-Gilbert (LLG) equation in case when several equilibrium positions are available for a disappearing magnetization state. It is shown that a particular hysteresis loop of a particle with cubic anisotropy may depend on the value of the damping parameter in the LLG equation. On the other hand, the upper and lower bounds for the coercive force of an assembly stated in the paper turn out to be very close to each other. The physical reason for the closeness of the upper and lower bounds is the fact that, for particles with cubic type of magnetic anisotropy, the fraction of the uniquely determined particular hysteresis loops is rather large. As a result, the coercive force of randomly oriented assembly with cubic anisotropy is almost independent of the value of the damping parameter. It is also shown that it has only weak dependence on the value of the second cubic anisotropy constant.","Cubic anisotropy; Hysteresis loop; Single-domain particles","Coercive force; Damping; Magnetic anisotropy; Magnetic domains; Magnetic hysteresis; Magnetization; Particles (particulate matter); Cubic anisotropy; Hysteresis loops; Landau Lifshitz Gilbert (LLG) equation; Single domain particles; Magnetic materials","","","","","","","Stoner E.C., Wohlfarth E.P., Trans. Roy. Soc. (London) A, 240, (1948); Kondorski E., Izv. Acad. Nauk, 16, (1952); Frei E.H., Strikman S., Treves D., Phys. Rev., 106, (1957); Aharoni A., J. Appl. Phys., 30, (1959); Brown W.F. Jr., Micromagnetics, (1963); Aharoni A., Phys. Stat. Sol., 16, (1966); Strikman S., Treves D., J. Phys. Radium, 20, (1959); Aharoni A., IEEE Trans. Magn., 5, (1969); Usov N.A., Peschany S.E., J. Magn. Magn. Mater., 147, (1995); Wohlfarth E.P., Magnetism, 3, (1963); Kneller E., Magnetism and Metallurgy, (1969); Gans R., Ann. Phys., 15, (1932); Johnson C.E. Jr., Brown W.F. Jr., J. Appl. Phys., 32, (1961); Lee E.W., Bishop J.E.L., Proc. Phys. Soc., 89, (1966); Joffe I., Heuberger R., Phil. Mag., 314, (1974); Korn G.A., Korn T.M., Mathematical Handbook, (1968); Antonov L.I., Osipov S.G., Khapaev M.M., Fis. Met. Metal., 57, (1984); Schabes M.E., J. Magn. Magn. Mater., 95, (1991); Usov N.A., Peschany S.E., J. Magn. Magn. Mater., 130, (1994); Gurevich A., Melkov G., Magnetic Oscillations and Waves, (1994); Krinchik G.S., Physics of Magnetic Phenomena, (1985)","N.A. Usov; Troitsk Inst. Innov. and Fusion Res., TRINITI, 142092, Troitsk, Russian Federation; email: usov@fly.triniti.troitsk.ru","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-0031549501" +"Matsuyama K.; Hirokado Y.; Asada H.","Matsuyama, K. (7201482789); Hirokado, Y. (57224233774); Asada, H. (7203075175)","7201482789; 57224233774; 7203075175","Micromagnetic computation for wall coercivity caused by magnetic nonuniformity","1991","Journal of Applied Physics","69","8","","4853","4855","2","5","10.1063/1.348226","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0040619608&doi=10.1063%2f1.348226&partnerID=40&md5=43eb6e585b7c3367323f13986c3e2a82","Department of Electrical Engineering, Kyushu University 36, Fukuoka 812, Japan","Matsuyama K., Department of Electrical Engineering, Kyushu University 36, Fukuoka 812, Japan; Hirokado Y., Department of Electrical Engineering, Kyushu University 36, Fukuoka 812, Japan; Asada H., Department of Electrical Engineering, Kyushu University 36, Fukuoka 812, Japan","The wall coercivity caused by the magnetic nonuniformity has been studied numerically. The Landau-Lifshits-Gilbert (LLG) equation is integrated by an explicit scheme of the modified Dufort-Frankel method. The computation was carried out for a two-dimensional grid system representing the magnetization direction in a magnetic film plane. Typical magnetic parameters for magneto-optic recording media were assumed. Spatial variations of uniaxial anisotropy were treated as the magnetic nonuniformity. The validity of our numerical approach was demonstrated with preliminary one-dimensional computations, compared to analytical solutions. A wall coercive field of 2.5 kOe was observed for the wall coupling with a pinning site (30-Å width and 360-Å spacing along the wall) of 10 times larger anisotropy compared to the ordinary region. A two-dimensional anisotropy variation (K=10 6-107 erg/cm3) with a wavelength larger than 60 Å also caused a wall coercivity on the order of 1 kOe, compared to those in magneto-optic recording media. It was also found that a fine pinning site on the order of 100 Å caused a notable coercivity for the bubble domain wall surrounding it.","","","","","","","","","Mansuripur M., J. Appl. Phys., 63, (1988); Suits J.C., J. Appl. Phys., 67, (1990); Matsuyama K., Konishi S., IEEE Trans. Magn., MAG-20, (1984); Konishi K.S., Matsuyama K., Yoshimatsu N., Sakai K., IEEE Trans. Magn., MAG-24, (1988); Slonczewski J.C., Int. J. Magnet., 2, (1972)","","","","","","","","","00218979","","","","English","","Article","Final","","Scopus","2-s2.0-0040619608" +"Machida K.; Hayashi N.; Yoneda Y.; Numazawa J.; Kohro M.; Tanabe T.","Machida, K. (58872203400); Hayashi, N. (36194961300); Yoneda, Y. (7201528559); Numazawa, J. (7003985135); Kohro, M. (36627263500); Tanabe, T. (57206439876)","58872203400; 36194961300; 7201528559; 7003985135; 36627263500; 57206439876","Characteristics of crosstalk in the reproduced output of a newly developed multi-channel MR head","2001","Journal of Magnetism and Magnetic Materials","226-230","PART II","","2054","2055","1","6","10.1016/S0304-8853(00)00822-2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33748706755&doi=10.1016%2fS0304-8853%2800%2900822-2&partnerID=40&md5=dd170866570fc6504959587d4852b54e","Rec. Tech. and Mech. Engin, NHK Science and Technical Research Labs., Setagaya-ku, Tokyo 157-8510, 1-10-11 Kinuta, Japan; Corporate Research and Development Laboratories, Pioneer Corporation, Saitama 350-2288, Japan","Machida K., Rec. Tech. and Mech. Engin, NHK Science and Technical Research Labs., Setagaya-ku, Tokyo 157-8510, 1-10-11 Kinuta, Japan; Hayashi N., Rec. Tech. and Mech. Engin, NHK Science and Technical Research Labs., Setagaya-ku, Tokyo 157-8510, 1-10-11 Kinuta, Japan; Yoneda Y., Corporate Research and Development Laboratories, Pioneer Corporation, Saitama 350-2288, Japan; Numazawa J., Corporate Research and Development Laboratories, Pioneer Corporation, Saitama 350-2288, Japan; Kohro M., Corporate Research and Development Laboratories, Pioneer Corporation, Saitama 350-2288, Japan; Tanabe T., Corporate Research and Development Laboratories, Pioneer Corporation, Saitama 350-2288, Japan","We prepared the multi-channel magnetoresistive head with a simple structural design and it has the advantages of high-density recording and ultra-high transfer rate. Characteristics of crosstalk in the reproduced output of our head have been estimated by a micromagnetic calculation using the Landau-Lifshitz-Gilbert (LLG) equation, while the specimen head was fabricated and evaluated. As a result, by applying a magnetic field of 40Oe only between adjacent channels, the crosstalk was much decreased without reducing the reproduced output. © 2001 Elsevier Science B.V. AU rights reserved.","Crosstalk; Micromagnetic calculation; Multi-channel mr head","Structural design; Adjacent channels; High-density recording; Landau-Lifshitz-Gilbert equations; Magnetoresistive heads; Micromagnetic calculations; MR heads; Multi channel; Transfer rates; Crosstalk","","","","","","","Ozue T., Shirai T., Saito T., Ikegami T., Kano H., Onodera S., IEEE Trans. Magn., 34, (1998); Nakatani Y., Uesaka Y., Hayashi N., Jpn. J. Appl. Phys., 28, (1989)","K. Machida; Rec. Tech. and Mech. Engin, NHK Science and Technical Research Labs., Setagaya-ku, Tokyo 157-8510, 1-10-11 Kinuta, Japan; email: machida@strl.nhk.or.jp","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-33748706755" +"Yoo I.; Lee S.-R.; Kim Y.K.","Yoo, Ilsang (7005731885); Lee, Seong-Rae (20734716400); Kim, Young Keun (24502952300)","7005731885; 20734716400; 24502952300","Magnetic tunnel junctions stabilized by modified synthetic antiferromagnets","2004","Physica Status Solidi (A) Applied Research","201","8","","1676","1679","3","2","10.1002/pssa.200304600","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-3142730059&doi=10.1002%2fpssa.200304600&partnerID=40&md5=3fd4c90d1592b6ca3841cebc915a84be","Div. of Mat. Science and Engineering, Korea University, Seoul 136-701, South Korea","Yoo I., Div. of Mat. Science and Engineering, Korea University, Seoul 136-701, South Korea; Lee S.-R., Div. of Mat. Science and Engineering, Korea University, Seoul 136-701, South Korea; Kim Y.K., Div. of Mat. Science and Engineering, Korea University, Seoul 136-701, South Korea","In a conventional magnetic tunnel junction (MTJ) using a synthetic antiferromagnet (SAF), the stray field from the pinned layer often causes poor switching asymmetry due to the thickness difference between two ferromagnetic layers separated by a Ru spacer [1]. To attain good bias point control, a modified synthetic antiferromagnet (MSAF) structure, consisting of an additional Ru/ferromagnet onto the SAF, was suggested. In this computational simulation study, we evaluated MR transfer characteristics with an attention paid on the bias point of an MTJ with an MSAF using LLG equation and we could find the better switching behaviour of free layer in MSAF as the size decreases. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.","","Antiferromagnetism; Control systems; Magnetostatics; Mathematical models; Optimization; Ruthenium; Tunnel junctions; Antiferromagnets; Magnetic tunnel junctions (MTJ); Submicrometer; Magnets","","","","","","","Uhm Y.R., Lim S.H., J. Magn. Magn. Mater., 239, (2002); Park J.-S., Lee S.-R., Kim Y.K., IEEE Trans. Magn., 39, (2003); Zhu J.G., Zheng Y., IEEE Trans. Magn., 34, (1998); LLG Micromagnetics Simulator™; Park J.-S., Lee S.-R., Kim Y.K., Lim S.H., J. Magn. Magn. Mater., 250, (2002)","Y.K. Kim; Div. of Mat. Science and Engineering, Korea University, Seoul 136-701, South Korea; email: ykim97@korea.ac.kr","","","","","","","","00318965","","PSSAB","","English","Phys Status Solidi A","Conference paper","Final","","Scopus","2-s2.0-3142730059" +"Serpico C.","Serpico, C. (23013514800)","23013514800","Nonlinear magnetization dynamics and magnetization switching in uniformly magnetized bodies","2005","Journal of Magnetism and Magnetic Materials","290-291 PART 1","","","48","54","6","8","10.1016/j.jmmm.2004.11.158","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944354199&doi=10.1016%2fj.jmmm.2004.11.158&partnerID=40&md5=35b1b523a2d8e24e3b4512090d3d5648","Department of Electrical Engineering, Univ. of Napoli Federico II, Napoli I-80125, via Claudio 21, Italy","Serpico C., Department of Electrical Engineering, Univ. of Napoli Federico II, Napoli I-80125, via Claudio 21, Italy","Magnetization dynamics in uniformly magnetized ferromagnetic bodies is studied by using Landau-Lifshitz-Gilbert (LLG) equation. This equation is written in a generalized form to take into account the effect of spin-polarized currents. The general properties of the corresponding nonlinear dynamical system are studied in detail. It is underlined that, in many experimental situations relevant to magnetic storage applications, LLG dynamics is a small perturbation of conservative precessional dynamics. In this respect, the conservative case is treated in detail and it is shown that analytical solutions of the conservative dynamics can be derived by using the existence of two integrals of motion. The (perturbed) dissipative LLG dynamics is then studied by developing appropriate perturbation techniques. The general methods of analysis discussed in the first part of the paper are applied to two particular problems: precessional switching and current-driven switching. The accuracy of theoretical predictions are tested by comparing analytical results with numerical solutions. © 2004 Published by Elsevier B.V.","Laundau-Lifshitz-Gilbert equation; Magnetization dynamics; Nonlinear dynamics and bifurcations; Spin-transfer torque","Algebra; Integral equations; Magnetic anisotropy; Magnetic field effects; Magnetization; Nonlinear systems; Switching; Torque; Current-driven switching; Landau-Lifshitz-Gilbert (LLG) equation; Magnetization dynamics; Nonlinear dynamical systems; Magnetic materials","","","","","MIUR-FIRB, (RBAU01B2T8)","This work is partially supported by Italian MIUR-FIRB (Contract no. RBAU01B2T8).","Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, (2000); Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Tsoi M., Et al., Phys. Rev. Lett., 80, (1998); Kiselev S.I., Et al., Lett. Nat., 425, (2003); Sun J.Z., J. Magn. Magn. Mater., 202, (1999); Sun J.Z., Phys. Rev. B, 62, (2000); Mallinson J.C., IEEE Trans. Magn., 36, (2000); Perko L., Differential Equations and Dynamical Systems, (1996); Wiggins S., Introduction to Applied Nonlinear Dynamical Systems and Chaos, (1990); Lvarez L.F., Pla O., Chubykalo O., Phys. Rev. B, 61, (2000); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 93, (2003); Bertotti G., Mayergoyz I.D., Serpico C., Physica B, 343, (2004); Hancock H., Elliptic Integrals, (1958); Bertotti G., Mayergoyz I.D., Serpico C., J. Appl. Phys., 95, (2004)","C. Serpico; Department of Electrical Engineering, Univ. of Napoli Federico II, Napoli I-80125, via Claudio 21, Italy; email: serpico@unina.it","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-14944354199" +"Shiiki K.; Furusawa M.; Atarashi E.","Shiiki, Kazuo (7006734250); Furusawa, Munehito (36627068500); Atarashi, Eijiro (6506637534)","7006734250; 36627068500; 6506637534","Stability of transverse and longitudinal bit in patterned media","2001","Journal of Magnetism and Magnetic Materials","226-230","PART II","","2048","2050","2","0","10.1016/S0304-8853(00)00821-0","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-78049334218&doi=10.1016%2fS0304-8853%2800%2900821-0&partnerID=40&md5=5d0aa387b23d9d1d8c70acc4e8a06144","Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan","Shiiki K., Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan; Furusawa M., Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan; Atarashi E., Department of Applied Physics and Physico-Informatics, Keio University, Yokohama 223-8522, Japan","The stability of the transverse and the longitudinal bit is studied by using Landau-Lifshitz-Gilbert (LLG) equation from initial magnetization state of ideal bit array. Relaxed magnetization states are calculated for the transverse and the longitudinal bit in the conventional media and in the patterned media with various anisotropic energies and saturation magnetizations. The bit in the patterned media is more stable than that in the conventional media at low anisotropic energy. The transverse bit in the patterned media is stable even at low anisotropic energies less than about 8 × 105 erg/cm 3. The shape anisotropy of the patterned media stabilizes the microscopic bit. The patterned media is hopeful for high-density magnetic recording. © 2001 Elsevier Science B.V. All rights reserved.","Magnetic recording; Magnetization-patterns; Micromagnetic calculation","Anisotropy; Magnetic recording; Magnetization; Saturation magnetization; Anisotropic energy; Bit arrays; High-density magnetic recording; Landau-Lifshitz-Gilbert equations; Magnetization patterns; Micromagnetic calculations; Patterned medias; Shape anisotropy; Anisotropic media","","","","","","","Hughes G.F., Digest of Intermag., (1999); Shiiki K., Mitsui Y., Hirata Y., J. Appl. Phys., 79, (1996); Atarashi E., Shiiki K., J. Appl. Phys., 86, (1999)","K. Shiiki; Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, Kohoku, Yokohama 223-8522, 3-14-1 Hiyoshi, Japan; email: shiiki@appi.keio.ac.jp","","Elsevier B.V.","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-78049334218" +"Uesaka Y.; Nakatani Y.; Hayashi N.","Uesaka, Yasutaro (35513921100); Nakatani, Yoshinobu (7202547641); Hayashi, Nobuo (35352133200)","35513921100; 7202547641; 35352133200","Dynamical calculation of magnetization reversal in elongated particles","1990","Journal of Applied Physics","67","9","","5146","5148","2","12","10.1063/1.344644","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0012710552&doi=10.1063%2f1.344644&partnerID=40&md5=1351e8cbb298739a6a8af8109b3669ce","Central Research Lab., Hitachi Ltd., Kokubunji, Tokyo 185, Japan; Department of Computer Science and Information Mathematics, University of Electro-Communications, Chofugaoka, Chofu, Tokyo, Japan","Uesaka Y., Central Research Lab., Hitachi Ltd., Kokubunji, Tokyo 185, Japan; Nakatani Y., Department of Computer Science and Information Mathematics, University of Electro-Communications, Chofugaoka, Chofu, Tokyo, Japan; Hayashi N., Department of Computer Science and Information Mathematics, University of Electro-Communications, Chofugaoka, Chofu, Tokyo, Japan","The Landau-Lifshitz-Gilbert (LLG) equation is directly solved to investigate squareness and time-dependent magnetization changes of elongated particles. Squareness scarcely changes until the particle size exceeds some critical value. The critical value increases with increasing aspect ratio. It was found that there are three kinds of magnetization reversal mechanism in elongated particles: flower1, flower2, and vortex particles. Some time interval is necessary for the irreversible transition to occur in all cases. In a flower1 particle, the transition occurs from the top and bottom planes. In flower2 and vortex particles, the irreversible transitions occur from vortex states. In a flower2 particle, during the irreversible transition process, all magnetic moments at the top and bottom planes rotate to the same direction; consequently, some magnetic moments rotate to the antiapplied-field direction and then rotate to the applied-field direction. In a vortex particle, each magnetic moment at the top and bottom planes rotates to the applied-field direction.","","","","","","","","","Brown W.F., Micromagnetics, (1963); Schabes M.E., Bertram N., J. Appl. Phys., 64, (1988); Schabes M.E., Bertram N., J. Appl. Phys., 64, (1988); Schabes M.E., Bertram N., IEEE Trans. Magn., MAG‐25, (1989); Yan Y.D., Della Torre E., J. Appl. Phys., 66, (1989); Fredkin D.R., Koehler T.R., IEEE Trans. Magn., MAG‐24, (1988); Fredkin D.R., Koehler T.R., IEEE Trans. Magn., MAG‐25; Victora R.H., J. Appl. Phys., 63, (1988); Yan Y.D., Della Torre E., IEEE Trans. Magn., MAG‐25, (1989)","","","","","","","","","00218979","","","","English","","Article","Final","","Scopus","2-s2.0-0012710552" +"Lopez-Diaz L.; Della Torre E.; Moro E.","Lopez-Diaz, L. (56243736600); Della Torre, E. (57203231169); Moro, E. (7005409234)","56243736600; 57203231169; 7005409234","The effect of thermal activation on the coercivity of domain walls","1999","Journal of Applied Physics","85","8 II A","","4367","4369","2","14","10.1063/1.369786","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0032620250&doi=10.1063%2f1.369786&partnerID=40&md5=ac8d30165f8ee6c47e7274f22cdc8ce7","Departamento de Fisica Aplicada, Universidad de Salamanca, Salamanca E-37071, Spain; Institute for Magnetics Research, George Washington University, Washington, DC 20052, United States; Departamento de Matematicas, Grupo Interdisciplinar Sist. C., Universidad Carlos III de Madrid, E-28911 Leganés, Madrid, Spain","Lopez-Diaz L., Departamento de Fisica Aplicada, Universidad de Salamanca, Salamanca E-37071, Spain; Della Torre E., Institute for Magnetics Research, George Washington University, Washington, DC 20052, United States; Moro E., Departamento de Matematicas, Grupo Interdisciplinar Sist. C., Universidad Carlos III de Madrid, E-28911 Leganés, Madrid, Spain","The effect of temperature is rarely taken into account in micromagnetic calculations. However, thermal perturbations are known to play an important role in magnetization reversal processes. In this article, a micromagnetic model that includes thermal perturbations is presented. A stochastic zero-mean Gaussian field is introduced in the Landau-Lifschitz-Gilbert equation and the corresponding Langevin equation is solved numerically. The model is used to study the effect of temperature on the coercivity of domain walls due to exchange and anisotropy wells as well as nonmagnetic inclusions. It is shown that, for exchange and anisotropy interactions, thermal perturbations can lower the critical field for which the wall breaks free from the inclusion. However, when magnetostatic fields are taken into account, thermal perturbations are found to inhibit the unpinning process. This phenomenon seems to be related to the long-range nature of dipolar interactions. © 1999 American Institute of Physics.","","Coercive force; Inclusions; Magnetic anisotropy; Magnetization; Magnetostatics; Mathematical models; Numerical analysis; Perturbation techniques; Random processes; Thermal effects; Domain walls; Landau-Lifschitz-Gilbert (LLG) equation; Langevin equation; Magnetic domains","","","","","","","Lopez Diaz L., Della Torre E., J. Appl. Phys., 83, (1998); Van Kampen N.G., Stochastic Processes in Physics and Chemistry, (1981); Garanin D.A., Phys. Rev. B, 55, (1997); Kloeden P.E., Platen E., Numerical Solution of Stochastic Differential Equations, (1992)","L. Lopez-Diaz; Departamento de Fisica Aplicada, Universidad de Salamanca, Salamanca E-37071, Spain; email: lld@gugu.usal.es","","American Institute of Physics Inc.","American Institute Of Physics; IEEE Magnetics Society","Proceedings of the 43rd Annual Conference on Magnetism and Magnetic Materials","9 November 1998 through 12 November 1998","Miami, FL","55194","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-0032620250" +"Bena C.; Balents L.","Bena, Cristina (6603123942); Balents, Leon (7003531157)","6603123942; 7003531157","Spin pumping and magnetization dynamics in ferromagnet-Luttinger liquid junctions","2004","Physical Review B - Condensed Matter and Materials Physics","70","24","245318","1","7","6","12","10.1103/PhysRevB.70.245318","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944385870&doi=10.1103%2fPhysRevB.70.245318&partnerID=40&md5=56525e787b3e51f096480f5b8ccf05a3","Department of Physics, Univ. of California at Santa Barbara, Santa Barbara, CA 93106, United States","Bena C., Department of Physics, Univ. of California at Santa Barbara, Santa Barbara, CA 93106, United States; Balents L., Department of Physics, Univ. of California at Santa Barbara, Santa Barbara, CA 93106, United States","We study spin transport between a ferromagnet (FM) with time-dependent magnetization and a conducting carbon nanotube or quantum wire, modeled as a Luttinger liquid (LL). The precession of the magnetization vector of the ferromagnet due, for instance, to an outside applied magnetic field causes spin pumping into an adjacent conductor. Conversely, the spin injection causes increased magnetization damping in the ferromagnet. We find that, if the conductor adjacent to the ferromagnet is a Luttinger liquid, spin pumping/damping is suppressed by interactions, and the suppression has clear Luttinger-liquid power-law temperature dependence. We apply our result to a few particular setups. First we study the effective Landau-Lifshitz-Gilbert (LLG) coupled equations for the magnetization vectors of the two ferromagnets in a FM-LL-FM junction. Also, we compute the Gilbert damping for a FM-LL and a FM-LL-metal junction. © 2004 The American Physical Society.","","carbon; ferromagnetic material; metal; article; conductance; electric current; electron spin resonance; liquid; magnetic field; magnetism; mathematical analysis; nanotube; quantum mechanics; transport kinetics","","carbon, 7440-44-0","","","Broida-Hirschfeller Foundation; Sloan and Packard Foundations; National Science Foundation, NSF, (DMR-9985255); Directorate for Mathematical and Physical Sciences, MPS, (9985255)","This work has been supported by the NSF through Grant No. DMR-9985255, and by the Sloan and Packard Foundations. C.B. was also supported by the Broida-Hirschfeller Foundation.","Schmidt G., Ferrand D., Molenkamp D.W., Filip A.T., Van Wees B.J., Phys. Rev. B, 62, (2000); Kikkawa J.M., Awschalom D.D., Nature (London), 397, (1999); Brouwer P.W., Phys. Rev. B, 58, (1998); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. B, 66, (2002); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett., 88, (2002); Brataas A., Tserkovnyak Y., Bauer G.E.W., Halperin B.I., Phys. Rev. B, 66, (2002); Gilbert T.L., Phys. Rev., 100, (1955); Landau L.D., Lifshitz E.M., Pitaevski L.P., Statistical Physics, 3rd Ed., 2 PART, (1980); Kane C.L., Fisher M.P.A., Phys. Rev. Lett., 68, (1994); Phys. Rev. B, 46, (1992); Balents L., Egger R., Phys. Rev. B, 64, (2001); Balents L.; Balents L., Egger R., Phys. Rev. Lett., 85, (2000); Bena C., Balents L., Phys. Rev. B, 65, (2002)","C. Bena; Department of Physics, Univ. of California at Santa Barbara, Santa Barbara, CA 93106, United States; email: cristina@physics.ucsb.edu","","American Physical Society","","","","","","10980121","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-14944385870" +"Deutsch J.M.; Mai T.; Narayan O.","Deutsch, J.M. (16236191700); Mai, Trieu (55538181000); Narayan, Onuttom (7101640875)","16236191700; 55538181000; 7101640875","Hysteresis multicycles in nanomagnet arrays","2005","Physical Review E - Statistical, Nonlinear, and Soft Matter Physics","71","2","026120","","","","14","10.1103/PhysRevE.71.026120","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-41349112146&doi=10.1103%2fPhysRevE.71.026120&partnerID=40&md5=28d4a1bafa46e58850df7dc857c2c765","Department of Physics, University of California, Santa Cruz, CA 95064, United States","Deutsch J.M., Department of Physics, University of California, Santa Cruz, CA 95064, United States; Mai T., Department of Physics, University of California, Santa Cruz, CA 95064, United States; Narayan O., Department of Physics, University of California, Santa Cruz, CA 95064, United States","We predict two physical effects in arrays of single-domain nanomagnets by performing simulations using a realistic model Hamiltonian and physical parameters. First, we find hysteretic multicycles for such nanomagnets. The simulation uses continuous spin dynamics through the Landau-Lifshitz-Gilbert (LLG) equation. In some regions of parameter space, the probability of finding a multicycle is as high as ∼0.6. We find that systems with larger and more anisotropic nanomagnets tend to display more multicycles. Our results also demonstrate the importance of disorder and frustration for multicycle behavior. Second, we show that there is a fundamental difference between the more realistic vector LLG equation and scalar models of hysteresis, such as Ising models. In the latter case spin and external field inversion symmetry is obeyed, but in the former it is destroyed by the dynamics, with important experimental implications. © 2005 The American Physical Society.","","Arrays; Computer simulation; Hamiltonians; Magnetic anisotropy; Magnetic devices; Magnetic hysteresis; Mathematical models; Probability; Vectors; Ising models; Landau-Lifshitz-Gilbert (LLG) equations; Nanomagnet arrays; Spin dynamics; Nanostructured materials","","","","","","","Steinmetz C.P., Trans. Am. Inst. Electr. Eng., 9, (1892); Barkhausen H., Z. Phys., 20, (1919); Katz J., J. Phys. Colloid Chem., 53, (1949); Emmett P.H., Cines M., J. Phys. Colloid Chem., 51, (1947); Wang Z.Z., Ong N.P., Phys. Rev. B, 34, (1986); Ortin J., Delaey L., Int. J. Non-linear Mech., 37, (2002); Ortin J., J. Appl. Phys., 71, (1992); Mee C.D., Daniel E.D., Magnetic Recording Technology, 2nd Ed., (1996); Deutsch J.M., Narayan O., Phys. Rev. Lett., 91, (2003); Fischer K.H., Hertz J.A., Spin Glasses, (1991); Abraham M.C., Schmidt H., Savas T.A., Smith H.I., Rose C.A., Ram R.J., J. Appl. Phys., 89, (2001); Schmidt H., Ram R.J., J. Appl. Phys., 89, (2001); Charap S.H., Lu P.L., He Y., IEEE Trans. Magn., 33, (1997); Bertram H.N., Zhou H., Gustafson R., IEEE Trans. Magn., 34, (1998); Weller D., Moser A., IEEE Trans. Magn., 35, (1999); Sabhapandit S., Dhar D., Shukla P., Phys. Rev. Lett., 88, (2002); Sethna J.P., Dahmen K., Kartha S., Krumhansl J.A., Roberts B.W., Shore J.D., Phys. Rev. Lett., 70, (1993); Barker J.A., Schreiber D.E., Huth B.G., Everett D.H., Proc. R. Soc. London, Ser. A, 386, (1983); Ortin J., J. Appl. Phys., 71, (1992); Pierce M.S., Et al., Phys. Rev. Lett., 90, (2003); Phys. Rev. Lett., 94, (2005); De Leeuw F.H., Van Den Doel R., Enz U., Rep. Prog. Phys., 43, (1980); Stoner E.C., Wohlfarth E.P., Philos. Trans. R. Soc. London, Ser. A, 240, (1948); Sandler G.M., Et al., J. Appl. Phys., 85, (1999)","","","","","","","","","15502376","","PLEEE","","English","Phys. Rev. E Stat. Nonlinear Soft Matter Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-41349112146" +"Spinu L.; Cimpoesu D.; Stoleriu L.; Stancu A.","Spinu, L. (9732365200); Cimpoesu, D. (6507485811); Stoleriu, L. (6603682281); Stancu, A. (14037953900)","9732365200; 6507485811; 6603682281; 14037953900","Micromagnetic Calculation of the Transverse Susceptibility of Patterned Media","2003","IEEE Transactions on Magnetics","39","5 II","","2516","2518","2","11","10.1109/TMAG.2003.816459","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0141885035&doi=10.1109%2fTMAG.2003.816459&partnerID=40&md5=0667574aae0f8863e785974efe48dbd0","Adv. Materials Research Institute, Department of Physics, University of New Orleans, New Orleans, LA 70148, United States; Faculty of Physics, Al. I. Cuza University, Iasi 6600, Romania","Spinu L., Adv. Materials Research Institute, Department of Physics, University of New Orleans, New Orleans, LA 70148, United States; Cimpoesu D., Faculty of Physics, Al. I. Cuza University, Iasi 6600, Romania; Stoleriu L., Faculty of Physics, Al. I. Cuza University, Iasi 6600, Romania; Stancu A., Faculty of Physics, Al. I. Cuza University, Iasi 6600, Romania","A micromagnetic model based on the Landau-Lif-shitz-Gilbert (LLG) equation for the transverse susceptibility (TS) of particulate media is presented. The model is able to take into account virtually any type of anisotropy including uniaxial, cubic, and unidirectional (exchange anisotropy), or any combinations of these anisotropies. The magnetostatic interaction between particles is also considered using a fast Fourier technique. The model is used to calculate the TS signal for two-dimensional arrays of particles (patterned media) with uniaxial and cubic anisotropy. It is shown that the effect of interaction strongly affects the TS signal for these magnetic systems.","Cubic anisotropy; Patterned media; Transverse susceptibility; Uniaxial anisotropy","Fast Fourier transforms; Magnetic anisotropy; Magnetic materials; Magnetostatics; Signal processing; Micromagnetics; Magnetic susceptibility","","","","","Advanced Materials Research Institute; CNCSIS; National Science Foundation, NSF, (2001-04)-RII-03)","Manuscript received January 6, 2003. This work was supported in part by the National Science Foundation under Grant (2001-04)-RII-03 and by the Romanian CNCSIS under Grant A. L. Spinu is with the Advanced Materials Research Institute and the Department of Physics, University of New Orleans, New Orleans, LA 70148 USA (e-mail: lspinu@uno.edu). D. Cimpoesu, L. Stoleriu, and A. Stancu are with the Faculty of Physics, Al. I. Cuza University, Iasi 6600, Romania (e-mail: alstancu@uaic.ro). Digital Object Identifier 10.1109/TMAG.2003.816459 Fig. 1. Transverse susceptibility experimental arrangement for an uniaxial single-domain ferromagnetic particle.","Aharoni A., Frei E.H., Shtrikman S., Treves D., The reversible susceptibility tensor of the Stoner-Wolfarth model, Bull. Res. Counc. Israel, 6 A, pp. 215-238, (1957); Spinu L., Stancu A., Srikanth H., O'Connor C.J., Effect of the second-order anisotropy constant on the transverse susceptibility of uniaxial ferromagnets, Appl. Phys. Lett., 80, pp. 276-278, (2002); Spinu L., Tung L.D., Kolesnichenko V., Fang J., Stancu A., O'Connor C.J., RF dynamics in nanoparticle systems with tuned strength of interactions, IEEE. Trans. Magn., 38, pp. 2607-2609, (2002); Gillete P.R., Oshima K., Magnetization by reversal rotation, J. Appl. Phys., 29, pp. 529-531, (1958); Stancu A., Spinu L., Transverse susceptibility of single domain particle systems, J. Optoelectron. Adv. Mater.; Mansuripur M., Giles R., Demagnetizing field computation for dynamic simulation of the magnetization reversal process, IEEE. Trans. Magn., 24, pp. 2326-2328, (1988); Stancu A., Spinu L., O'Connor C.J., Micromagnetic analysis of the transverse susceptibility of particulate systems, J. Magn. Magn. Mater., 242-245, pp. 1026-1029, (2002); Spinu L., Stancu A., Srikanth H., O'Connor C.J., Micromagnetic study of reversible transverse susceptibility, Physica B, 306, pp. 221-227, (2001); Ross C.A., Smith H.I., Savas T., Schattenburg M., Farhoud M., Hwang M., Walsh M., Abraham M.C., Ram R.J., Fabrication of patterned media for high density magnetic storage, J. Vac. Sci. Technol. B, 17, pp. 3168-3176, (1999); O'Handley R.C., Modern Magnetic Materials - Principles and Applications, (2000); Chang C.-R., Yang J.-S., Mean field interaction and transverse susceptibility, IEEE. Trans. Magn., 30, pp. 4095-4097, (1994)","L. Spinu; Adv. Materials Research Institute, Department of Physics, University of New Orleans, New Orleans, LA 70148, United States; email: lspinu@uno.edu","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0141885035" +"Magni A.; Bertotti G.; Mayergoyz I.D.; Serpico C.","Magni, A. (7007060492); Bertotti, G. (7005370974); Mayergoyz, I.D. (35495971500); Serpico, C. (23013514800)","7007060492; 7005370974; 35495971500; 23013514800","Landau-Lifschitz-Gilbert dynamics and eddy current effects in metallic thin films","2003","Journal of Magnetism and Magnetic Materials","254-255","","","210","212","2","3","10.1016/S0304-8853(02)00765-5","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0037211391&doi=10.1016%2fS0304-8853%2802%2900765-5&partnerID=40&md5=77b0f053e35aa072ab7d824aab60e37c","IEN Galileo Ferraris, I-10125 Torino, Corso Massimo D'Azeglio 42, Italy; Dept. of Elec. and Computer Eng., University of Maryland, College Park, MD 20742, United States; INFM Napoli, Department of Electrical Engineering, University Federico II, I-80125 Napoli, Italy","Magni A., IEN Galileo Ferraris, I-10125 Torino, Corso Massimo D'Azeglio 42, Italy; Bertotti G., IEN Galileo Ferraris, I-10125 Torino, Corso Massimo D'Azeglio 42, Italy; Mayergoyz I.D., Dept. of Elec. and Computer Eng., University of Maryland, College Park, MD 20742, United States; Serpico C., INFM Napoli, Department of Electrical Engineering, University Federico II, I-80125 Napoli, Italy","The behavior of a metallic magnetic film subject to a circularly polarized field is studied using the Landau-Lifshitz-Gilbert (LLG) equation for the magnetization coupled with Maxwell equations for the eddy current field. In the limit in which exchange interactions are neglected and dissipation is low an approximate picture is obtained, in which intrinsic plus eddy current dissipation effects are described by an effective z-dependent damping constant α′(z), increasing from the minimum value at the surface to the maximum value at the film center. Approximate solutions for the film magnetic response are obtained and their stability is discussed. © 2002 Elsevier Science B.V. All rights reserved.","Eddy currents; Landau-Lifshitz-Gilbert equation; Spin dynamics; Thin films","Approximation theory; Eddy currents; Magnetization; Maxwell equations; Metallic films; Problem solving; Spin dynamics; Magnetic thin films","","","","","","","Ludwig A., Et al., IEEE Trans. Mag., 37, (2001); Yamaguchi M., Et al., J. Appl. Phys., 85, (1999); Shin K., Inoue M., Arai K., J. Appl. Phys., 85, (1999); Korenivski V., J. Magn. Magn. Mater., 215-216, (2000); Yamaguchi M., Et al., J. Magn. Magn. Mater., 215-216, (2000); Sandler G.M., Bertram H.N., J. Appl. Phys., 81, (1997); Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, (2001); Bertotti G., Et al., J. Appl. Phys., 89, (2001); Mayergoyz I.D., Bertotti G., Serpico C., J. Appl. Phys., 87, (2000); Mayergoyz I.D., Serpico C., Shimizu Y., J. Appl. Phys., 87, (2000); Magni A., Et al., Physica B, 306, (2001); Sandler G.M., Et al., J. Appl. Phys., 85, (1999)","G. Bertotti; IEN Galileo Ferraris, I-10125 Torino, Corso Massimo D'Azeglio 42, Italy; email: bertotti@ien.it","","","","SMM15","5 September 2001 through 7 September 2001","Bilbao","60370","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-0037211391" +"Covington M.; Rebei A.; Parker G.J.; Seigler M.A.","Covington, M. (7005536523); Rebei, A. (6602595953); Parker, G.J. (7402344444); Seigler, M.A. (6602676771)","7005536523; 6602595953; 7402344444; 6602676771","Spin momentum transfer in current perpendicular to the plane spin valves","2004","Applied Physics Letters","84","16","","3103","3105","2","16","10.1063/1.1707227","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-2442612587&doi=10.1063%2f1.1707227&partnerID=40&md5=91c9490dcf8e3eb5584194a0b8807e35","Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States","Covington M., Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States; Rebei A., Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States; Parker G.J., Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States; Seigler M.A., Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States","The experimental and numerical micromagnetic data on the effect of spin momentum transfer, in current perpendicular to the plane spin valves, were studied. The free-layer magnetization exhibits abrupt current-induced switching that was qualitatively consistent with the spin torque model, starting from a configuration with orthogonal free and pinned-layer magnetizations. The spin transfer can produce a change in resistance that mimics an effective magnetic field and induce magnetic instability that requires a larger bias field in order to stabilize the device, when operating the spin valve as a field sensor. The numerical micromagnetic calculations of the Landau-Lifsgitz-Gilbert (LLG) equation, with the spin torque term included were also performed.","","Electric potential; Electric resistance; Hard disk storage; Magnetic anisotropy; Magnetic fields; Magnetic flux; Magnetization; Magnetoresistance; Multilayers; Sensors; Thin films; Magnetic stability; Plane spin valves; Spin momentum transfer; Threshold current; Electron tubes","","","","","","","Nagasaka K., Seyama Y., Varga L., Shimizu Y., Tanaka A., J. Appl. Phys., 89, (2001); Seigler M.A., Van der Heijden P.A.A., Litvinov A.E., Rottmayer R.E., IEEE Trans. Magn., 39, (2003); Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Grollier J., Cros V., Hamzic A., George J.M., Jaffres H., Fert A., Faini G., Youssef J.B., Legall H., Appl. Phys. Lett., 78, (2001); Sun J.Z., Monsma D.J., Abraham D.W., Rooks M.J., Koch R.H., Appl. Phys. Lett, 81, (2002); Urazhdin S., Birge N.O., Pratt Jr. W.P., Bass J., Phys. Rev. Lett., 91, (2003); Mancoff F.B., Dave R.W., Rizzo N.D., Esehrich T.C., Engel B.N., Tehrani S., Appl. Phys. Lett., 83, (2003); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Seck M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, (1998); Ji Y., Chien C.L., Stiles M.D., Phys. Rev. Lett., 90, (2003); Rippard W.H., Pufall M.R., Silva T.J., Appl. Phys. Lett., 82, (2003); Kiselev S.I., Sankey J.C., Krivorotov I.N., Emley N.C., Schoelkopf R.J., Buhrman R.A., Ralph D.C., Nature (London), 425, (2003); Rippard W.H., Pufall M.R., Kaka S., Russek S.E., Silva T.J., Phys. Rev. Lett., 92, (2004); Covington M., AlHajDarwish M., Ding Y., Gokemeijer N.J., Seigler M.A., Phys. Rev. B; Li Z., Zhang S., Phys. Rev. B, 68, (2003)","M. Covington; Seagate Research, Pittsburgh, PA 15222, 1251 Waterfront Place, United States; email: Mark.Covington@seagate.com","","","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-2442612587" +"D'Aquino M.; Serpico C.; Miano G.; Mayergoyz I.D.; Bertotti G.","D'Aquino, M. (9732823500); Serpico, C. (23013514800); Miano, G. (7006758103); Mayergoyz, I.D. (35495971500); Bertotti, G. (7005370974)","9732823500; 23013514800; 7006758103; 35495971500; 7005370974","Numerical integration of Landau-Lifshitz-Gilbert equation based on the midpoint rule","2005","Journal of Applied Physics","97","10","10E319","","","","29","10.1063/1.1858784","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944445503&doi=10.1063%2f1.1858784&partnerID=40&md5=b3a055312cc704457f73b69d9db24c34","Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; Istituto Elettrotecnico Nazionale, Galileo Ferraris, 91 I-10135, Torino, Strada delle Cacce, Italy","D'Aquino M., Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; Serpico C., Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; Miano G., Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; Bertotti G., Istituto Elettrotecnico Nazionale, Galileo Ferraris, 91 I-10135, Torino, Strada delle Cacce, Italy","The midpoint rule time discretization technique is applied to Landau-Lifshitz-Gilbert (LLG) equation. The technique is unconditionally stable and second-order accurate. It has the important property of preserving the conservation of magnetization amplitude of LLG dynamics. In addition, for typical forms of the micromagnetic free energy, the midpoint rule preserves the main energy balance properties of LLG dynamics. In fact, it preserves LLG Lyapunov structure and, in the case of zero damping, the system free energy. All the above preservation properties are fulfilled unconditionally, namely, regardless of the choice of the time step. The proposed technique is then tested on the standard micromagnetic problem No. 4. In the numerical computations, the magnetostatic field is computed by the fast Fourier transform method, and the nonlinear system of equations connected to the implicit time-stepping algorithm is solved by special and reasonably fast quasi-Newton technique. © 2005 American Institute of Physics.","","Algorithms; Damping; Fourier transforms; Magnetic field effects; Magnetization; Magnetostatics; Set theory; Exchange constants; Landau-Lifshitz-Gilbert (LLG) equations; Magnetostatic fields; Neumann conditions; Integration","","","","","MIUR-FIRB, (RBAU01B2T8)","This work is partially supported by the Italian MIUR-FIRB under Contract No. RBAU01B2T8 and by “Programma Scambi Internazionali, University di Napoli Federico II.”","μ -mag Group Website; Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 89, (2001); Krishnaprasad P.S., Tan X., Physica B, 306, (2001); Lewis D., Nigam N., J. Comput. Appl. Math., 151, (2003); Budd C.J., Piggott M.D., Geometric Integration and Its Applications, (2001); Austin M.A., Krishnaprasad P.S., J. Comput. Phys., 107, (1993); Aharoni A., Introduction to the Theory of Ferromagnetism, (2001); Saad Y., Schultz M.H., SIAM (Soc. Ind. Appl. Math.) J. Sci. Stat. Comput., 7, (1986); Schabes M.E., Aharoni A., IEEE Trans. Magn., 23, (1987); Albuquerque G., Miltat J., Thiaville A., J. Appl. Phys., 89, (2001)","M. D'Aquino; Department of Electrical Engineering, University of Napoli Federico II, Napoli, Italy; email: mdaquino@unina.it","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","All Open Access; Bronze Open Access","Scopus","2-s2.0-20944445503" +"Tanaka T.; Hong Y.-K.; Gee S.-H.; Park M.-H.; Erickson D.W.; Byun C.","Tanaka, Terumitsu (55727221200); Hong, Yang-Ki (7403393257); Gee, Sung-Hoon (9244817800); Park, Mun-Hyoun (7404490740); Erickson, Dustin W. (7203016145); Byun, Chongwor (16554360100)","55727221200; 7403393257; 9244817800; 7404490740; 7203016145; 16554360100","Analytical calculation for estimation of magnetic film properties for a 3-GHz thin film inductor","2004","IEEE Transactions on Magnetics","40","4 II","","2005","2007","2","6","10.1109/TMAG.2004.832251","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-4444258927&doi=10.1109%2fTMAG.2004.832251&partnerID=40&md5=5545597bba90b7ee17c76c9da2345a03","Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States","Tanaka T., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States; Hong Y.-K., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States; Gee S.-H., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States; Park M.-H., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States; Erickson D.W., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States; Byun C., Dept. of Mat. Sci. and Engineering, University of Idaho, Moscow, ID 83844-3024, United States","Thickness, resistivity, and the Gilbert damping constant are estimated using Maxwell and Landau-Lifshitz-Gilbert (LLG) equations to meet operating parameters of ferromagnetic thin film inductors in the gigahertz frequency range. The following properties of soft magnetic film are calculated to satisfy a quality factor of 10 at 3 GHz: 4πMS = 21.3 kG: Hk - 215 Oe; and μ′dc = 100. The complex permeability was not influenced by film thickness up to 100 nm. Operation frequency increases with the increase of electrical resistivity and decrease of film thickness. The Gilbert damping constant is found to have a significant effect on the operation frequency. The quality factor can be retained up to 3 GHz for 100-nm-thick film with a damping constant of 0.015 when resistivity is greater than 50 μΩ · cm.","Ferromagnetic resonance; LLG equations; Soft magnetic materials; Thin film inductor","Damping; Eddy currents; Electric conductivity; Ferromagnetic resonance; Frequencies; Magnetic anisotropy; Magnetic materials; Magnetic permeability; Quality control; Thick films; Thickness measurement; Damping constants; Film thickness; Landau-Lifshitz-Gilbert (LLG) equations; Thin film inductors; Magnetic thin films","","","","","Office of Naval Research, ONR, (N00014-03-1-0819)","Manuscript received February 17, 2004. This work was supported by the Office of Naval Research under Grant N00014-03-1-0819. The authors are with the Department of Materials Science and Engineering, University of Idaho, Moscow, ID 83844-3024 USA (e-mail: ykhong@uidaho.edu). Digital Object Identifier 10.1109/TMAG.2004.832251 Fig. 1. Relationship of the dc permeability, saturation magnetization, and anisotropy field for FMR frequencies of 4.0, 5.0, and 6.0 GHz.","Chen L.H., Zhu W., Tiefel T.H., Jin S., Van Dover R.B., Korenivski V., Fe-Cr-Hf-N and Fe-Cr-Ta-N soft magnetic thin films, IEEE Trans. Magn., 33, pp. 3811-3813, (1997); Jin S., Zhu W., Van Dover R.B., Tiefel T.H., Korenivski V., Chen L.H., High frequency properties of Fe-Cr-Ta-N soft magnetic films, Appl. Phys. Lett., 70, pp. 3161-3163, (1997); Chen L.H., Shih Y.H., Ellis K.A., Jin S., Van Dover R.B., Klemmer T.J., Effect of post-annealing on ultra-high frequency properties of amorphous Fe-Co-B thin films, IEEE Trans. Magn., 36, pp. 3418-3420, (2000); Ludwig A., Lohndorf M., Tewes M., Quandt E., Magnetoelastic thin films for high-frequency applications, IEEE Trans. Magn., 37, pp. 2690-2692, (2001); Sun N.X., Wang S.X., Silva T.J., Kos A.B., High-frequency behavior and damping of Fe-Co-N-based high-saturation soft magnetic films, IEEE Trans. Magn., 38, pp. 146-150, (2002); Tanabe S., Siraki Y., Itoh K., Yamaguchi M., Arai K., FEM analysis of thin film inductors used in GHz frequency bands, IEEE Trans. Magn., 35, pp. 3580-3582, (1999); Huijbregtse J., Roozeboom F., Donkers J., Kuiper T., Van De Riet E., High-frequency permeability of soft-magnetic Fe-HF-O films with high resistivity, J. Appl. Phys., 83, pp. 1569-1574, (1998)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-4444258927" +"Deak J.G.","Deak, James G. (7005123422)","7005123422","Spin injection in thermally assisted magnetic random access memory","2005","Journal of Applied Physics","97","10","10E316","","","","5","10.1063/1.1855200","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944433371&doi=10.1063%2f1.1855200&partnerID=40&md5=43956ce28e8e2383557e732916af8f4b","Nonvolatile Electronics (NVE) Corporation, Eden Prairie, MN 55344, 11409 Valley View Road, United States","Deak J.G., Nonvolatile Electronics (NVE) Corporation, Eden Prairie, MN 55344, 11409 Valley View Road, United States","An integrated thermal, micromagnetic, spin-momentum-transfer (SMT) model was developed to study the effect of SMT on the programming current required for thermally assisted magnetic random access memory (MRAM). The thermal portion of the model is used to compute Joule heating by the spin-polarized current, and it is based on a Crank-Nicolson inhomogeneous heat equation solver. The magnetic portion of the model is based on a micromagnetic Langevin dynamic Landau-Lifshitz-Gilbert solver including SMT torque. Simulations of thermally assisted magnetization reversal of 0.09-μm MRAM elements, heated by passing current through the barrier separating the pinned and free layers, were performed. The free layer of the MRAM elements was switched using a magnetic field at fixed heating-SMT current bias. Results suggest that a spin-polarized heating current can be used to lower the programming current required to write thermally assisted MRAM if the direction of the heating current is properly synchronized with the reversal field. © 2005 American Institute of Physics.","","Computer simulation; Electric currents; Heating; Magnetic field effects; Magnetization; Random access storage; Torque; Joule heating; Landau-Lifshitz-Gilbert (LLG) solver; Magnetic random access memory (MRAM); Spin injection; Magnetic storage","","","","","Defense Advanced Research Projects Agency, DARPA; Missile Defense Agency, MDA"," This work was funded in part by DARPA and MDA. ","Daughton J.M., Pohm A.V., Tondra M.C., (2004); Daughton J.M., Spintronics Applications at NVE, (2004); Sun J.Z., Phys. Rev. B, 62, (2000); Koch R.H., Katine J.A., Sun J.Z., Phys. Rev. Lett., 92, (2004); Li S., Zhang S., Phys. Rev. B, 69, (2004); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Deak J.G., J. Appl. Phys., 93, (2003); Slonczewski J., J. Magn. Magn. Mater., 159, (1996); Grinstein G., Koch R.H., Phys. Rev. Lett., 90, (2003)","Nonvolatile Electronics (NVE) Corporation, Eden Prairie, MN 55344, 11409 Valley View Road, United States; email: jdeak@nve.com","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-20944433371" +"Torres L.; Lopez-Diaz L.; Martinez E.; Alejos O.","Torres, L. (56926909600); Lopez-Diaz, L. (56243736600); Martinez, E. (55414779800); Alejos, O. (7003574826)","56926909600; 56243736600; 55414779800; 7003574826","Micromagnetic dynamic computations including eddy currents","2003","Digests of the Intermag Conference","","","","CA01","","","2","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0141792789&partnerID=40&md5=732417afab9fd91d2d26b87220a713f3","Universidad de Salamanca, Dept. de Fisica Aplicada, 37008 Salamanca, Plaza de la Merced s/n, Spain; Universidad de Valladolid, Dept. de Electricidad, 47071 Valladolid, Spain","Torres L., Universidad de Salamanca, Dept. de Fisica Aplicada, 37008 Salamanca, Plaza de la Merced s/n, Spain; Lopez-Diaz L., Universidad de Salamanca, Dept. de Fisica Aplicada, 37008 Salamanca, Plaza de la Merced s/n, Spain; Martinez E., Universidad de Salamanca, Dept. de Fisica Aplicada, 37008 Salamanca, Plaza de la Merced s/n, Spain; Alejos O., Universidad de Valladolid, Dept. de Electricidad, 47071 Valladolid, Spain","A 3D dynamic micromagnetic model which includes the effect of eddy currents and its application to magntization reversal processes in permalloy nanocubes was presented. A cubic permalloy sample of 40 nm side was discretized in cubic cells of 5×5×5 nm3 to illustrate the effect of eddy currents. The magnetization dynamics was evaluated by solving the Landau-Lifschitz-Gilbert (LLG) equation.","","Boundary conditions; Computer simulation; Damping; Eddy currents; Electric conductivity; Fast Fourier transforms; Magnetization; Maxwell equations; Nanostructured materials; Switching; Permalloy nanocubes; Magnetic materials","","","","","","","Della Torre E., Eicke J., IEEE Trans. Mag., 33, (1997); Sandler G.M., Bertram H.N., J. Appl. Phys., 81, (1997); Torres L., Lopez-Diaz L., Martinez E., Iniguez J., Physica B, 306, (2001)","","","","Magnetics Society of the IEEE","Intermag 2003: International Magnetics Conference","28 March 2003 through 3 April 2003","Boston, MA","61560","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0141792789" +"Gao Y.; Zhu J.; Weng Y.; Han B.","Gao, Youhui (6505793711); Zhu, Jinghan (7405688808); Weng, Yuqing (7103320133); Han, Baoshan (36666329800)","6505793711; 7405688808; 7103320133; 36666329800","Domain structure in Fe-implanted Nd2Fe14B magnets","1999","Applied Physics Letters","74","12","","1749","1751","2","22","10.1063/1.123676","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0032613773&doi=10.1063%2f1.123676&partnerID=40&md5=7377924cb41ffc85f4043fadbd8c7833","Advanced Materials Institute, Ctrl. Iron and Stl. Res. Institute, Beijing 100081, China; State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China","Gao Y., Advanced Materials Institute, Ctrl. Iron and Stl. Res. Institute, Beijing 100081, China; Zhu J., Advanced Materials Institute, Ctrl. Iron and Stl. Res. Institute, Beijing 100081, China; Weng Y., Advanced Materials Institute, Ctrl. Iron and Stl. Res. Institute, Beijing 100081, China; Han B., State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China","Nd2Fe14B thin flakes whose normal direction is [001] were implanted using Fe ions. Their domain structures were investigated by magnetic force microscopy (MFM) in order to obtain insight into the effects of Fe ion implantation on their surface magnetic structures. The magnetization arrangements of ion-implanted samples were numerically simulated using the Landau-Lifshitz-Gilbert (LLG) equation.","","Crystal microstructure; Ion implantation; Iron; Magnetic domains; Magnetic moments; Mathematical models; Microscopic examination; Neodymium alloys; Landau-Lifshitz-Gilbert (LLG) equation; Magnetic force microscopy; Magnetic thin films","","","","","","","Coehoorn R., De Mooji D.B., Duchateau J.P.W.B., Buschow K.H., J. Phys., 49, (1988); Panagiotupoulos L., Withanawasam L., Murthy A.S., Hadjipanayis G.C., J. Appl. Phys., 79, (1996); Ding J., McCormick P.G., Street R., J. Magn. Magn. Mater., 124, (1993); Kneller E.F., Hawig R., IEEE Trans. Magn., 27, (1991); Skomski R., Coey J.M.D., Phys. Rev. B, 48, (1993); Ossi P.M., Radiat. Eff. Defects Solids, 108, (1989); Zhang T., Wang X., Liang H., Zhang H., Zhou G., Sun G., Zhao W., Xue J., Surf. Coat. Technol., 83, (1996); Bodenberger R., Hubert A., Phys. Status Solidi A, 44, (1977); Rave W., Ramstock K., J. Magn. Magn. Mater., 171, (1997); Brown W.F. Jr., Micromagnetics, (1963); Youhui G., (1998)","","","American Institute of Physics Inc.","","","","","","00036951","","APPLA","","English","Appl Phys Lett","Article","Final","","Scopus","2-s2.0-0032613773" +"Panagiotopoulos A.Z.; Reid R.C.","Panagiotopoulos, A.Z. (7006335566); Reid, R.C. (55605774305)","7006335566; 55605774305","NEW MIXING RULE FOR CUBIC EQUATIONS OF STATE FOR HIGHLY POLAR, ASYMMETRIC SYSTEMS.","1986","ACS Symposium Series","","","","571","582","11","226","10.1021/bk-1986-0300.ch028","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0022562305&doi=10.1021%2fbk-1986-0300.ch028&partnerID=40&md5=2cc649acbcb6ed72e99a21c405483a7c","MIT, Cambridge, MA, USA, MIT, Cambridge, MA, USA","Panagiotopoulos A.Z., MIT, Cambridge, MA, USA, MIT, Cambridge, MA, USA; Reid R.C., MIT, Cambridge, MA, USA, MIT, Cambridge, MA, USA","A new two-parameter mixing rule for van der Waals-type cubic equations of state was developed by making the normally used single binary interaction parameter k//i//j a linear function of composition. A significant improvement was observed in the representation of binary and ternary phase equilibrium data for highly polar and asymmetric systems. Results are presented for systems with water and supercritical fluids at high pressures, as well as for low-pressure non-ideal systems. Ternary phase equilibrium data at high pressures, including LLG three-phase equilibria, were successfully correlated using parameters regressed from binary data only.","","LIQUIDS - Phase Equilibria; CUBIC EQUATIONS OF STATE; POLAR-SUPERCRITICAL FLUID SYSTEMS; THREE-PHASE EQUILIBRIA; TWO PARAMETER MIXING RULE; Equations of state","","","","","","","","","","ACS","ACS, Div of Industrial & Engineering Chemistry, Washington, D","Equations of State: Theories and Applications. Developed from a Symposium at the 189th Meeting of the American Chemical Society.","","Miami Beach, FL, USA","8374","00976156","0841209588; 978-084120958-9","ACSMC","","English","ACS Symp Ser","Conference paper","Final","","Scopus","2-s2.0-0022562305" +"Baňas L.; Slodička M.","Baňas, L'ubomír (24079505700); Slodička, Marián (6701450594)","24079505700; 6701450594","Space discretization for the Landau-Lifshitz-Gilbert equation with magnetostriction","2005","Computer Methods in Applied Mechanics and Engineering","194","2-5 SPEC. ISS.","","467","477","10","11","10.1016/j.cma.2004.06.021","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-10444222623&doi=10.1016%2fj.cma.2004.06.021&partnerID=40&md5=ea2c4ad6d6fba45ffac95aa985d6878a","Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium","Baňas L., Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium; Slodička M., Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium","We consider the conservation of momentum equation for the displacement vector together with a nonlinear dissipative magnetic law described by Landau-Lifshitz-Gilbert (LLG) equation. This system describes the magnetostriction caused by an applied magnetic field. We use a finite element approximation and we design a numerical scheme for computations. We derive the error estimates for the approximation of the displacement vector and the magnetization. © 2004 by Elsevier B.V. All rights reserved.","Ferromagnetism; Finite elements; Magnetostriction","finite element method; magnetism; Computational methods; Energy dissipation; Error detection; Magnetic field effects; Magnetization; Mathematical models; Vectors; Landau-Lifshitz-Gilbert (LLG) equation; Nonlinear dissipative magnetic law; Space discretization; Magnetostriction","","","","","STWW, (12 052 499, 174 IW 300); Agentschap voor Innovatie door Wetenschap en Technologie, IWT; Universiteit Gent","L. Baňas was supported by the IWT/STWW project no. 174 IW 300, M. Slodička by the BOF/GOA-project no. 12 052 499 of Ghent University. The authors thank R. Van Keer, coordinator of these projects, for his stimulation.","Weiss P., L'hypothèse du champ moléculaire et la proprièté ferromagnetique, J. Phys., 6, pp. 661-690, (1907); Landau L., Lifshitz E., On the theory of the dispersion of magnetic permeability in ferromagnetic bodies, Phys. Z. Sowjetunion, 8, pp. 153-169, (1935); Landau L., Lifshitz E., Electrodynamics of Continuous Media, (1960); Anzellotti G., Baldo S., Visintin A., Asymptotic behavior of the Landau-Lifshitz model of ferromagnetism, Appl. Math. Opt., 23, 3, pp. 171-192, (1991); Guo B., Ding S., Neumann problem for the Landau-Lifshitz-Maxwell system in two dimensions, Chinese Ann. Math., Ser. B, 22, 4, pp. 529-540, (2001); Guo B., Su F., Global weak solution for the Landau-Lifshitz-Maxwell equation in three space dimensions, J. Math. Anal. Appl., 211, 1, pp. 326-346, (1997); Su F., Guo B., The global smooth solution for Landau-Lifshitz-Maxwell equation without dissipation, J. Partial Differ. Equations, 11, 3, pp. 193-208, (1998); Visintin A., On Landau-Lifshitz' equations for ferromagnetism, Jpn. J. Appl. Math., 2, pp. 69-84, (1985); Monk P., Vacus O., Error estimates for a numerical scheme for ferromagnetic problems, SIAM J. Numer. Anal., 36, 3, pp. 696-718, (1998); Vandevelde L., Melkebeek J., A survey of magnetic force distributions based on different magnetization models and on the virtual work principle, IEEE Trans. Magn., 37, 5, pp. 3405-3409, (2001); Vandevelde L., Melkebeek J., Computation of deformation of ferromagnetic material, IEEE Proc. Sci. Meas. Technol., 149, (2002); Sablik M., Jiles D., Coupled magnetoelastic theory of magnetic and magnetostrictive hysteresis, IEEE Trans. Magn., 29, 3, pp. 2113-2123, (1993); Brenner S., Scott L., The Mathematical Theory of Finite Element Methods, (1994); Slodicka M., Banas L., A numerical scheme for a Maxwell-Landau-Lifshitz-Gilbert system, Appl. Math. Comput.; Slodicka M., Cimrak I., Numerical study of nonlinear ferromagnetic materials, Appl. Numer. Math., 46, 1, pp. 11-95, (2003)","L. Baňas; Department of Mathematical Analysis, Ghent University, B-9000 Ghent, Galglaan 2, Belgium; email: lubomir.banas@ugent.be","","","","","","","","00457825","","CMMEC","","English","Comput. Methods Appl. Mech. Eng.","Article","Final","","Scopus","2-s2.0-10444222623" +"Miyashita E.; Taguchi R.; Funabashi N.; Tamaki T.; Okuda H.","Miyashita, E. (7004694330); Taguchi, R. (36948685100); Funabashi, N. (7003826900); Tamaki, T. (7202609924); Okuda, H. (7202093306)","7004694330; 36948685100; 7003826900; 7202609924; 7202093306","Effects of the exchange stiffness constant and the distribution on the recording characteristics of perpendicular media","2002","INTERMAG Europe 2002 - IEEE International Magnetics Conference","","","1001167","","","","0","10.1109/INTMAG.2002.1001167","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85017264406&doi=10.1109%2fINTMAG.2002.1001167&partnerID=40&md5=88778757bdb5dac078b7192e316cd7d0","NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan","Miyashita E., NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan; Taguchi R., NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan; Funabashi N., NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan; Tamaki T., NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan; Okuda H., NHK Science and Technical Research Labs., 1-10-11 Kinuta, Setagaya-ku, 157-8510, Tokyo, Japan","In order to clarify the effects of exchange stiffness and the distribution on the recording characteristics of perpendicular media, we performed a micromagnetic simulation based on the LLG equation. The magnetization loops and recorded magnetization pattern are calculated. ©2002 IEEE.","","Magnetization; Exchange stiffness; LLG equation; Magnetization loops; Magnetization patterns; Micromagnetic simulations; Perpendicular media; Recording characteristics; Stiffness","","","","","","","","","Fidler J.; Hillebrands B.; Ross C.; Weller D.; Folks L.; Hill E.; Vazquez Villalabeitia M.; Bain J.A.; De Boeck J.; Wood R.","Institute of Electrical and Electronics Engineers Inc.","","2002 IEEE International Magnetics Conference, INTERMAG Europe 2002","28 April 2002 through 2 May 2002","Amsterdam","116193","","0780373650; 978-078037365-5","","","English","INTERMAG Europe - IEEE Int. Magn. Conf.","Conference paper","Final","","Scopus","2-s2.0-85017264406" +"Chen A.P.; Britel M.R.; Zhukova V.; Zhukov A.; Dominguez L.; Chizhik A.B.; Blanco J.M.; González J.","Chen, A.P. (55309160000); Britel, M.R. (6602127962); Zhukova, V. (56207513400); Zhukov, A. (56160242800); Dominguez, L. (7103341989); Chizhik, A.B. (56251750000); Blanco, J.M. (58904538900); González, Julián (7404493359)","55309160000; 6602127962; 56207513400; 56160242800; 7103341989; 56251750000; 58904538900; 7404493359","Influence of AC magnetic field amplitude on the surface magnetoimpedance tensor in amorphous wire with helical magnetic anisotropy","2004","IEEE Transactions on Magnetics","40","5","","3368","3377","9","13","10.1109/TMAG.2004.833433","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-4644264478&doi=10.1109%2fTMAG.2004.833433&partnerID=40&md5=0689d3a2b125400dc836da5bc95cd1a4","Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; Instituto de Ciencias de Materiales, CSIC, Cantoblanco, 28049 Madrid, Spain; TAMag Iberica S.L., Parque Tecn. de Miramón, 20009 San Sebastián, Spain; Department of Applied Physics I, EUPDS, UPV/EHU, San Sebastián 20018, Spain","Chen A.P., Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; Britel M.R., Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; Zhukova V., Instituto de Ciencias de Materiales, CSIC, Cantoblanco, 28049 Madrid, Spain, TAMag Iberica S.L., Parque Tecn. de Miramón, 20009 San Sebastián, Spain; Zhukov A., Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; Dominguez L., Department of Applied Physics I, EUPDS, UPV/EHU, San Sebastián 20018, Spain; Chizhik A.B., Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; Blanco J.M., Department of Applied Physics I, EUPDS, UPV/EHU, San Sebastián 20018, Spain; González J., Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain","We have performed experimental and theoretical studies on the influence of ac magnetic field amplitude on the magnetoimpedance tensor in an amorphous wire with helical magnetic anisotropy. For the experimental measurements, we used an amorphous wire of composition (Co0.94Fe0.06) 72.5Si12.5B15 with negative, nearly zero magnetostriction constant, excited either by an ac circular hφ or by an axial hz magnetic field created by an ac electric current. We changed the ac current amplitude from 7.5 to 40 mA and the current frequency / from 1.5 to 20 MHz. The values of the asymmetric giant magnetoimpedance ratio associated with the sweeping direction of the dc field Hex and the corresponding sensitivity were 211% and 0.64 V/Oe, respectively, for an ac current of 37.5 mA at 3 MHz. For the theoretical study based on the magnetization rotation, we obtained the second-order harmonic of the ac magnetization m→(2) induced by the relatively high ac magnetic field by solving the Landau-Lifshitz-Gilbert (LLG) equation. We also considered a second-order surface impedance tensor ζ(2) which allowed us to analyze quantitatively the influence of the ac magnetic field amplitude on the impedance tensor of the wire. We obtained the domain model of the wire with helical magnetic anisotropy having multidomains and the magnetization vector ±M0 directed in the easy direction, and the corresponding static magnetic configurations, by solving the static LLG equation. For the given magnetic configurations, we calculated the second-order impedance tensor ζ(2). The results can well explain the irregular field characteristics ofthe voltage responses at low dc field value, when the wire was excited at high frequency and at large ac magnetic field.","Impedance tensor; Induced anisotropy; Magnetoimpedance effect","Acoustic impedance; Composition; Electric currents; Electric potential; Magnetic anisotropy; Magnetic field effects; Magnetization; Magnetostriction; Natural frequencies; Tensors; Amorphous wire; Impedance tensor; Induced anisotropy; Magnetoimpedance effect; Amorphous materials","","","","","North Atlantic Treaty Organization, NATO","V. Zhukova wishes to acknowledge the NATO postdoctoral fellowship.","Beach R.S., Berkowitz A.E., Giant magnetic field dependent impedance of amorphous FeCoSiB wire, Appl. Phys. Lett., 64, (1994); Panina L.V., Mohri K., Magneto-impedance effect in amorphous wires, Appl. Phys. Lea., 65, (1994); Velazquez J., Vazquez M., Chen D.-X., Hernando A., Giant magnetoimpedance in nonmagnetostrictive amorphous wires, Phys. Rev. B, 50, (1994); Rao K.V., Humphrey F.B., Costa-Kramer J.L., Very large magnetoimpedance in amorphous soft ferromagnetic wires, J. Appl. Phys., 76, (1994); Mohri K., Panina L.V., Uchiyama K.T., Bushida K., Noda M., Sensitive and quick response micro magnetic sensor utilizing magnetoimpedance in Co-rich amorphous wires, IEEE Trans. Magn., 31, pp. 1266-1275, (1995); Panina L.V., Mohri K., Bushida K., Noda M., Giant magnetoimpedance in Co-rich amorphous wires and films, IEEE Trans. Magn., 31, pp. 1249-1260, (1995); Vazquez M., Hemado A., A soft magnetic wire for sensor applications, J. Phys. D, Appl. Phys., 29, (1996); Yelon A., Menard D., Britel M., Ciureanu P., Calculations of giant magnetoimpedance and of ferromagnetic resonance response are rigorously equivalent, Appl. Phys. Lett., 69, (1996); Makhnovskiy D.P., Panina L.V., Mapps D.J., Measurement of field-dependent surface impedance tensor in amorphous wires with circumferential anisotropy, J. Appl. Phys., 87, (2000); Field-dependent surface tensor in amorphous wires with two types of magnetic anisotropy: Helical and circumferential, Phys. Rev. B, 63, (2001); Aragoneses P., Zhukov A.P., Gonzalez J., Blanco J.M., Dominguez L., Effect of AC driving current on magneto-impedance effect, Sens. Actuators A, 81, (2000); Dominguez L., Blanco J.M., Aragoneses P., Gonzalez J., Circumferential magnetization processes in CoFeBSi wires, J. Appl. Phys., 79, (1996); Freijo J.J., (2001); Beach R.S., Smith M., Platt C.L., Jeffers F., Berkowitz A.E., Magnetoimpedance effect in NiFe plated wire, Appl. Phys. Lett., 68, (1996); Chiriac H., Hristoforou E., Neagu M., Darie I., Barariu F., D.C. magnetic field measurements based on the inverse Wiedemann effect in Fe-rich glass covered amorphous wires, IEEE Trans. Magn., 35, pp. 3625-3627, (1999); Antonov A.S., Buznikov N.A., Iakubov I.T., Lagarkov A.N., Rakhmanov A.L., Nonlinear magnetization reversal of Co-based amorphous microwires induced by an ac current, J. Phys. D, Appl. Phys., 34, (2001); Gomez-Polo C., Vazquez M., Pirota K.R., Knobel M., Giant magnetoimpedance modeling using Fourier analysis in soft magnetic amorphous wires, Phys. B, 299, (2001); Zhukova V.A., Chizhik A.B., Gonzalez J., Makhnovskiy D.P., Panina L.V., Mapps D.J., Zhukov A.P., Effect of annealing under torsion stress on the field dependence of the impedance tensor in amorphous wires, J. Magn. Magn. Mater., 249, (2002); Makhnovskiy D.P., Panina L.V., Mapps D.J., Asymmetrical magnetoimpedance in as-cast CoFeSiB amorphous wires due to ac bias, Appl. Phys. Lett., 77, (2000); Landau L.D., Lifshitz E.M., Electrodynamics of Continuous Media, 2nd Ed., (1984); Mohri K., Et al., Large barkhausen and matteucci effects in FeCoSiB, FeCrSiB and FeNiSiB amorphous wires, IEEE Trans. Magn., 26, pp. 1789-1791, (1990); Humphrey F.B., Mohri K., Et al., Re-entrant magnetic flux reversal in amorphous wires, Magnetic Properties of Amorphous Metals, 110, (1987); Stoner E.C., Wohlfarth E.P., A mechanism of magnetic hysteresis in heterogeneous alloys, Phil. Trans. R. Soc., A-240, pp. 599-642, (1948); Antonov A.S., Buznikov N.A., Granovsky A.B., Iakubov I.T., Prodoshin A.F., Radhmanov A.L., Yakunin A.M., Magnetization reversal process and nonlinear magnetoimpedance in Cu/NiFe and Nb/NiFe composite wires, J. Magn. Magn. Mater., 249, (2002); Antonov A.S., Buznikov N.A., Filatov M.M., Goncharov V.P., Rakhmano A.A., Rakhmanov A.L., Effects of longitudinal AC magnetic field on frequency spectrum of voltage response of soft magnetic conductors, J. Magn. Magn. Mater., 258, (2003); Zhao K.H., Chen X.M., Electromagnetism (II), People's Education: Bei Jin P, (1978); Chen D.-X., Pascual L., Castano F.J., Vazquez M., Hernando A., Revised core-shell domain model for magnetostrictive amorphous wires, IEEE Trans. Magn., 37, pp. 994-1002, (2001); Takajo M., Yamasaki J., Humphrey F.B., Domain observations of Fe and Co based amorphous wires, IEEE Trans. Magn., 30, pp. 3484-3486, (1993); Ogasawara I., Mohri K., Preparation and properties of amorphous wires, IEEE Trans Magn., 26, (1995); Chizhik A., Zhukova V., Zhukov A., Blanco J.M., Gonzalez J., Effect of annealing on surface domain structure and magnetostriction of near-zero magnetostrictive Co-rich wire, J. Magn. Magn. Mater., 242, (2002)","A.P. Chen; Department of Material Physics, Chemistry Faculty, Universidad del Pais Vasco, 20080 San Sebastián, Spain; email: scyther@wanadoo.es","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-4644264478" +"Peng B.; Zhang W.L.; Zhang W.X.; Jiang H.C.; Yang S.Q.","Peng, B. (7102873085); Zhang, W.L. (8892049000); Zhang, W.X. (8395837200); Jiang, H.C. (7404465947); Yang, S.Q. (8983320800)","7102873085; 8892049000; 8395837200; 7404465947; 8983320800","Simulation of stress impedance effect in magnetoelastic films","2005","Journal of Magnetism and Magnetic Materials","288","","","326","330","4","6","10.1016/j.jmmm.2004.09.114","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-13544262324&doi=10.1016%2fj.jmmm.2004.09.114&partnerID=40&md5=e30024d90327867da8e1e5be0de1e3d7","Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China","Peng B., Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China; Zhang W.L., Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China; Zhang W.X., Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China; Jiang H.C., Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China; Yang S.Q., Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China","Extensive studies have been conducted in magnetoelastic films because of its application in stress sensors based on the stress impedance effect. In this paper, the stress impedance effects have been studied based on the Landau-Lifshitz-Gilbert equation. The results show that the stress impedance effects are strongly dependent on the thickness of the magnetoelastic film, the residual stress and the uniaxial magnetic anisotropy. © 2004 Elsevier B.V. All rights reserved.","LLG equation; Magnetoelastic films; Stress impedance effect","Elasticity; Magnetic anisotropy; Magnetization; Mathematical models; Residual stresses; Sensors; Strain; Stress analysis; LLG equation; Magnetoelastic films; Magnetoelastic materials; Stress impedance effect; Magnetic films","","","","","","","Ludwig A., Frommberger M., Tewes M., Et al., IEEE Trans. Magn., 39, (2003); Ludwig A., Lohndorf M., Tewes M., Et al., IEEE Trans. Magn., 37, (2001); Li D.R., Lu Z.C., Zhou S.X., Sensors and Actuators A, 109, (2003); Shen L.P., Uchiyama T., Mohri K., Et al., IEEE Trans. Magn., 33, (1997); Shin K.H., Inoue M., Arai K.I., J. Appl. Phys., 85, (1999); Hideya Y., Yuji N., J. Appl. Phys., 87, (2000); Lndau L.D., Lifshitz E.M., Electrodynamics of Continuous Media, (1975); Bozorth R.M., Ferromagnetism, (1955); Kraus L., J. Magn. Magn. Mater., 195, (1999)","B. Peng; Sch. Microlectron. Solid State E., Univ. Electron. Sci. Technol. China, Chengdu 610054, China; email: bpeng@uestc.edu.cn","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-13544262324" +"Ho J.; Khanna F.C.; Choi B.C.","Ho, Jeongwon (58457534100); Khanna, F.C. (7006397641); Choi, B.C. (7402755257)","58457534100; 7006397641; 7402755257","Radiation-spin interaction, gilbert damping, and spin torque","2004","Physical Review Letters","92","9","097601","097601","1","-97600","31","10.1103/PhysRevLett.92.097601","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-2442661598&doi=10.1103%2fPhysRevLett.92.097601&partnerID=40&md5=0e58f74a6862a9d6c77572df91b5b406","Department of Physics, University of Victoria, Victoria, BC, Canada; Department of Physics, University of Alberta, Edmonton, Alta., Canada; TRIUMF, 4004 Westbrook Mall, Vancouver, BC, Canada","Ho J., Department of Physics, University of Victoria, Victoria, BC, Canada; Khanna F.C., Department of Physics, University of Alberta, Edmonton, Alta., Canada, TRIUMF, 4004 Westbrook Mall, Vancouver, BC, Canada; Choi B.C., Department of Physics, University of Victoria, Victoria, BC, Canada","Magnetization relaxation processes, which are represented by the Gilbert damping term and the spin torque term in the Landau-Gilbert (LLG) equation was described using radiation-spin interaction (RSI) method. It was observed that the damping imposed on the presessing magnetization originates from the magnetization precessional motion. The magnetization relaxation process determined by the RSI was found to depend on the nature of coupling between the spin and the radiation field produced by precessing magnetization. It was shown that the LLG equation including the Gilbert damping term and the spin torque term is derived from the spin Hamiltonian containing the RSI.","","Damping; Demagnetization; Equations of motion; Ferromagnetic materials; Hamiltonians; Magnetization; Mathematical models; Nuclear magnetic resonance spectroscopy; Thin films; Torque; Gilbert damping; Micromagnetic structures; Radiation-spin interaction; Spin torque; Relaxation processes","","","","","Natural Sciences and Engineering Research Council of Canada, NSERC"," J. H. is grateful to D. Page for the warm hospitality at University of Alberta and to W. Kim for helpful discussions. This work was supported by Natural Sciences and Engineering Research Council of Canada.","Landau L.D., Lifshitz E.M., Pitaevski L.P., Statistical Physics, Part 2, (1980); Gilbert T.L., Phys. Rev., 100, (1955); Kambersky V., Can. J. Phys., 48, (1970); Korenman V., Prange R.E., Phys. Rev. B, 6, (1972); Heinrich B., Meredith D.J., Cochran J.F., J. Appl. Phys., 50, (1979); Sparks M., Ferromagnetic-relaxation theory, Advanced Physics Monograph Series, (1964); Patton C.E., Wilts C.H., Humphrey B., J. Appl. Phys., 38, (1967); Heinrich B., Cochran J.F., Hasegawa R., J. Appl. Phys., 57, (1985); Hurben M.J., Franklin D.R., Patton C.E., J. Appl. Phys., 81, (1997); Arias R., Mills D.L., Phys. Rev. B, 60, (1999); Azevedo A., Oliveira A.B., De Aguiar F.M., Rezende S.M., Phys. Rev. B, 62, (2000); Urban R., Heinrich B., Woltersdorf G., Ajdari K., Myrtle K., Cochran J.F., Rozenberg E., Phys. Rev. B, 65, (2002); McMichael R.D., Twisselmann D.J., Phys. Rev. Lett., 90, (2003); Baryakhtar V.G., Ivanov B.A., Sukstanskii A.L., Melikhov E.Yu., Phys. Rev. B, 56, (1997); Suhl H., IEEE Trans. Magn., 34, (1998); Safonov V.L., Bertram H.N., J. Appl. Phys., 85, (1999); Boerner E.D., Bertram H.N., Suhl H., J. Appl. Phys., 87, (2000); Smith N., Arnett P., Appl. Phys. Lett., 78, (2001); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Berger L., J. Appl. Phys., 91, (2002); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Seek M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, (1998); Myers E.B., Ralph D.C., Katine J.A., Louie R.N., Buhrman R.A., Science, 258, (1999); Sun J.Z., J. Magn. Magn. Mater., 202, (1999); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Tsoi V., Wyder P., Nature (London), 406, (2000); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Grollier J., Gros V., Hamzic A., George J.M., Jaffres H., Fert A., Faini G., Ben Youssef J., Legall K., Appl. Phys. Lett, 78, (2001); Urban R., Woltersdorf G., Heinrich B., Phys. Rev. Lett., 87, (2001); Sun J.Z., Monsma D.J., Rooks M.J., Koch R.H., Appl. Phys. Lett., 81, (2002); Wegrowe J.E., Kelly D., Jaccard Y., Guittienne Ph., Ansermet J.Ph., Europhys. Lett, 45, (1999); Wegrowe J.E., Hoffer X., Guittienne Ph., Fabian A., Gravier L., Wade T., Ansermet J.Ph., J. Appl. Phys., 91, (2002); Bazaliy Ya.B., Jones B.A., Zhang S.-C., Phys. Rev. B, 57, (1998); Waintal X., Myers E.B., Brouwer P.W., Ralph D.C., Phys. Rev. B, 62, (2000); Heide C., Phys. Rev. B, 65, (2002); Stiles M.D., Zangwill A., Phys. Rev. B, 66, (2002); Li Z., Zhang S., Phys. Rev. B, 68, (2003); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); White R.M., Quantum Theory of Magnetism, (1983); Heinrich B., Tserkovnyak Y., Woltersdorf G., Brataas A., Urban R., Bauer G.E.W., Phys. Rev. Lett., 90, (2003); Tserkovnyak Y., Brataas A., Bauer G.E.W., Phys. Rev. Lett, 88, (2002); Augustine M.P., Prog. Nucl. Magn. Reson. Spectrosc., 40, (2002); Jackson J.D., Classical Electrodynamics, (1975); Simanek E., Heinrich B., Phys. Rev. B, 67, (2003)","","","American Physical Society","","","","","","00319007","","PRLTA","","English","Phys Rev Lett","Article","Final","","Scopus","2-s2.0-2442661598" +"He L.; Doyle W.D.","He, L. (56324371600); Doyle, W.D. (7103092933)","56324371600; 7103092933","A theoretical description of magnetic switching experiments in picosecond field pulses","1996","Journal of Applied Physics","79","8 PART 2B","","6489","6491","2","57","10.1063/1.361979","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0000909520&doi=10.1063%2f1.361979&partnerID=40&md5=8bc21950da4eee27b11322e8b38420d9","Ctr. of Mat. for Info. Technology, Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487-0209, United States","He L., Ctr. of Mat. for Info. Technology, Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487-0209, United States; Doyle W.D., Ctr. of Mat. for Info. Technology, Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487-0209, United States","Siegmann et al. have reported that the magnetization in a perpendicularly oriented CoPt film with a uniaxial anisotropy field of 20 000 Oe was reversed when the film was exposed to a 20 000 Oe in-plane pulsed field lasting only 6 ps. From a calculation based on the Gilbert form of the Landau-Lifshitz equation (LLG), it is shown that the experimental result is consistent with the LLG model even for values of the damping constant a as larger as 0.5. The dependence of the switching time on the anisotropy field and the applied field are presented as a function of a and the angle β between the applied field and the easy axis. Experiments are suggested which could illuminate the damping mechanism at these very short times. © 1996 American Institute of Physics.","","","","","","","National Science Foundation, NSF, (0903651)","","Soohoo R.F., Magnetic Thin Films, (1965); Freeman M.R., Ruf R.R., Gambino R.J., IEEE Trans. Magn., 27, (1991); Siegmann H.C., Garwin E.I., Prescott C.Y., Heidmann J., Mauri D., Weller D., Allenspach P., Weber W., J. Magn. Magn. Mater.; Heidmann J., Weller D., Siegmann H.C., Garwin E.I., Conference on Magnetism and Magnetic Materials, (1995); He L., Doyle W.D., Fujiwara H., IEEE Trans. Magn., 30, (1994); Gillette P.R., Oshima K., J. Appl. Phys., 29, (1958); Kikuchi R., J. Appl. Phys., 27, (1956)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-0000909520" +"Bertotti G.; Magni A.; Bonin R.; Mayergoyz I.D.; Serpico C.","Bertotti, Giorgio (7005370974); Magni, Alessandro (7007060492); Bonin, Roberto (9736915400); Mayergoyz, Isaak D. (35495971500); Serpico, Claudio (23013514800)","7005370974; 7007060492; 9736915400; 35495971500; 23013514800","Analytical description of magnetization relaxation to equilibrium","2005","Journal of Applied Physics","97","10","10E315","","","","6","10.1063/1.1854421","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944448863&doi=10.1063%2f1.1854421&partnerID=40&md5=d55867f1d9ce622feb1a4be8bcfd97c0","Materials Department, Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino, 10135 Torino, Italy; Dipartimento di Fisica, Politecnico di Torino, 10129 Torino, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; Dipartimento di Ingegneria Elettrica, Universit̀ di Napoli Federico II, 80125 Napoli, Italy","Bertotti G., Materials Department, Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino, 10135 Torino, Italy; Magni A., Materials Department, Istituto Elettrotecnico Nazionale Galileo Ferraris, Torino, 10135 Torino, Italy; Bonin R., Dipartimento di Fisica, Politecnico di Torino, 10129 Torino, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; Serpico C., Dipartimento di Ingegneria Elettrica, Universit̀ di Napoli Federico II, 80125 Napoli, Italy","Approximate analytical expressions are obtained for the magnetization relaxation to equilibrium in a thin film element with in-plane anisotropy subject to a constant external field applied along the easy axis. First, exact analytical solutions are obtained for the constant-energy motions taking place in the limit case where the damping constant is zero. Then a separate equation is derived and solved for the slow relaxation to equilibrium of the system energy. Final expressions for the magnetization relaxation are obtained by using the ensuing time-dependent energy in the solutions for the undamped dynamics. © 2005 American Institute of Physics.","","Crystals; Damping; Magnetic anisotropy; Magnetic field effects; Magnetic relaxation; Thin films; Damping constant; Landau-Lifshitz-Gilbert (LLG) equation; Magnetization motion; Magnetization relaxation; Magnetization","","","","","MIUR-FIRB; U.S. Department of Energy, USDOE"," This work was partially supported by the U.S. Department of Energy and by MIUR-FIRB Contract No. RBAU01B2T8. ","Back C., Weller D., Heidmann J., Mauri D., Guarisco D., Garwin E., Siegmann H., Phys. Rev. Lett., 81, (1998); Kaka S., Russek S., Appl. Phys. Lett., 80, (2002); Back C., Allenspach R., Weber W., Parkin S., Weller D., Garwin E., Siegmann H., Science, 285, (1999); Schumacher H., Chappert C., Sousa R., Freitas P., Miltat J., Phys. Rev. Lett., 90, (2003); Kiselev S., Sankey J., Krivorotov I., Emley N., Schoelkopf R., Buhrman R.A., Ralph D., Nature (London), 425, (2003); Bertotti G., Mayergoyz I., Serpico C., J. Appl. Phys., 95, (2004); Serpico C., Mayergoyz I., Bertotti G., J. Appl. Phys., 93, (2003); Thiaville A., Phys. Rev. B, 61, (2000); Donahue M.J., Porter D.G., IEEE Trans. Magn., 38, (2002)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-20944448863" +"Toussaint J.C.; Marty A.; Vukadinovic N.; Youssef J.B.; Labrune M.","Toussaint, J.C. (35502756000); Marty, A. (7102217534); Vukadinovic, N. (6603955826); Youssef, J.B. (55903005800); Labrune, M. (56209599700)","35502756000; 7102217534; 6603955826; 55903005800; 56209599700","A new technique for ferromagnetic resonance calculations","2002","Computational Materials Science","24","1-2","","175","180","5","29","10.1016/S0927-0256(02)00183-0","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0036577816&doi=10.1016%2fS0927-0256%2802%2900183-0&partnerID=40&md5=4be0426ff907c3abdba3da1ff2743d0e","Laboratoire Louis Néel, CNRS, 38042 Grenoble Cédex 9, France; CEA-Grenoble, Département De Recherche Fondamentale Sur La Matière Condensée/SP2M, 38054 Grenoble Cédex 9, France; DTA/EM Dassault Aviation, 92552 Saint-Cloud, France; Laboratoire De Magnétisme De Bretagne, UMR CNRS 6135, Université, 29285 Brest, France; Laboratoire LPMTM, Institut Galilée, Université Paris-13, 93430 Villetaneuse, France","Toussaint J.C., Laboratoire Louis Néel, CNRS, 38042 Grenoble Cédex 9, France; Marty A., CEA-Grenoble, Département De Recherche Fondamentale Sur La Matière Condensée/SP2M, 38054 Grenoble Cédex 9, France; Vukadinovic N., DTA/EM Dassault Aviation, 92552 Saint-Cloud, France; Youssef J.B., Laboratoire De Magnétisme De Bretagne, UMR CNRS 6135, Université, 29285 Brest, France; Labrune M., Laboratoire LPMTM, Institut Galilée, Université Paris-13, 93430 Villetaneuse, France","A new approach for calculating high-frequency response spectra of ferromagnetic materials exhibiting inhomogenous configurations is presented here. Our software (GL_FFT copyright CNRS, Lab. Louis Néel, Grenoble) is based on the direct numerical integration of the Landau-Lifschift-Gilbert equation (noted LLG hereafter) using a finite difference method coupled with FFT techniques for the calculation of demagnetizing fields. Our technique is well adapted to simulate the magnetization dynamics and the relaxation processes in thin magnetic films. The dynamic Polder tensor P(ω) is deduced from the time-frequency transformation of the response δm(t) of the space average magnetization due to a weak uniform magnetic excitation δh(t). The whole spectrum is obtained from only one relaxation process, by using a step function for the excitation. Our technique is compared to the so-called dynamic matrix technique obtained by linearizing the LLG equation. Its application to epitaxial FePd thin films with perpendicular anisotropy is finally presented. © 2002 Elsevier Science B.V. All rights reserved.","","Computer software; Fast Fourier transforms; Ferromagnetic materials; Finite difference method; Magnetic anisotropy; Magnetic relaxation; Magnetic thin films; Magnetization; Magnetic excitation; Ferromagnetic resonance","","","","","","","Vukadinovic N., Vacus O., Labrune M., Acher O., Pain D., Phys. Rev. Lett., 85, (2000); Labbe S., Bertin P.-Y., J. Magn. Magn. Mater., 206, (1999); Gerardin O., Le Gall H., Donahue M.J., Vukadinovic N., J. Appl. Phys., 89, (2001); Brown W.F. Jr., Rev. Mod. Phys., 17, (1945); Brown W.F. Jr., Micromagnetics, (1963); Ramstock K., Leibl T., Hubert A., J. Magn. Magn. Mater., 135, (1994); Hayashi N., Saito K., Nakatani Y., Jpn. J. Appl. Phys., 35, (1996); Toussaint J.C., Kevorkian B., Givord D., Rossignol M.F., Proceedings of the 9th International Symposium Magnetic Anisotropy and Coercivity in Rare-Earth Transition Metal Alloys, 2, (1996); Nakatani Y., Uesaka Y., Hayashi N., Jpn. J. Appl. Phys., 28, (1989); Vukadinovic N., Le Gall H., Ben Youssef J., Gehanno V., Marty A., Samson Y., Gilles B., Eur. Phys. J. B, 13, (2000)","A. Marty; CEA-Grenoble, DRFMC/SP2M, 38054 Grenoble Cédex 9, France; email: amarty@cea.fr","","","","","","","","09270256","","CMMSE","","English","Comput Mater Sci","Conference paper","Final","","Scopus","2-s2.0-0036577816" +"Nozaki Y.; Matsuyama K.; Ono T.; Miyajima H.","Nozaki, Yukio (7103269992); Matsuyama, Kimihide (7201482789); Ono, Tenio (35501261400); Miyajima, Hideki (7102348364)","7103269992; 7201482789; 35501261400; 7102348364","Micromagnetic structure analysis of head-on-head-type 180° domain wall in submicron size Co wires","1999","Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers","38","11","","6282","6286","4","11","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033350566&partnerID=40&md5=e860db1ef8c1b8dbc0675088177a424a","Graduate School of Information Science and Electrical Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, 6-10-1, Higashi, Japan; Faculty of Science and Technology, Kcio University, Kolwkti, Yokohama 223-8522, Hiyoshi 3-14-1, Japan","Nozaki Y., Graduate School of Information Science and Electrical Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, 6-10-1, Higashi, Japan, Faculty of Science and Technology, Kcio University, Kolwkti, Yokohama 223-8522, Hiyoshi 3-14-1, Japan; Matsuyama K., Graduate School of Information Science and Electrical Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, 6-10-1, Higashi, Japan; Ono T., Graduate School of Information Science and Electrical Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, 6-10-1, Higashi, Japan; Miyajima H., Graduate School of Information Science and Electrical Engineering, Kyushu University, Hakozaki, Fukuoka 812-8581, 6-10-1, Higashi, Japan","Micromagnetic structures of the 180° domain wall in submicron-size ferromagnetic Co wires were investigated by means of magnetic force microscopy. The domain wall width δ (approximately μm) observed in the Co wire is about 10 times larger than that observed in Co films of the same thickness. From micromagnetic calculations using the Landau-Lifshitz-Gilbert (LLG) equation, the magnetic structure of the 180° domain wall is expected to be a large vortex accompanied by a magnetic ripple structure. This complicated 180° domain wall is formed to reduce the demagnetizing energy due to a head-on-head configuration of the magnetization, which results in a micron-scale transition area of the domain wall. The wire width dependence of the 180° domain wall width obtained by micromagnetic calculations is almost consistent with that measured from the magnetic force micrograph.","","Cobalt; Computational methods; Demagnetization; Magnetic domains; Magnetic thin films; Magnetization; Mathematical models; Metallic films; Wire; Domain wall; Ferromagnetic wires; Landau-Lifshitz-Gilbert equation; Magnetic force microscopy; Micromagnetic structure analysis; Ferromagnetic materials","","","","","","","Ranmuth K.T., Pohm A.V., Dauglilon J.M., Comstok C.S., IEEE Trans. Magn., 29, (1993); Martin Y., Williams C.C., Wickramasinghe H.K., J. Appl. Phys, 61, (1987); Lohndorf M., Wadas A., Van Den Berg H.A.M., Wicsendanger R., Appl. Phys. Lett., 68, (1996); Berkov D.V., Ramstock K., Hubert A., Phys. Status Solidi A, 137, (1993); Babcock K., Dugas M., Maralis S., Elings V., Mater. Res. Soc. Symp. Proc., 355, (1996); Femandez A., Gibbons M.R., Wall M.A., Cerjan C.J., J. Magn. Magn. Matter., 190, (1998); McMichacl R.D., Donahue M.J., IEEE Trans. Magn., 33, (1997)","","","JJAP","","","","","","00214922","","JAPND","","English","Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap","Article","Final","","Scopus","2-s2.0-0033350566" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, Giorgio (7005370974); Mayergoyz, Isaak D. (35495971500); Serpico, Claudio (23013514800)","7005370974; 35495971500; 23013514800","Perturbation technique for LLG dynamics in uniformly magnetized bodies subject to RF fields","2002","IEEE Transactions on Magnetics","38","5 I","","2403","2405","2","6","10.1109/TMAG.2002.803596","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0036762458&doi=10.1109%2fTMAG.2002.803596&partnerID=40&md5=2b7e03f206842535d4bfdb4050fb6207","IEN Galileo Ferraris, I-10125 Torino, Italy; Dept. of Electrical and Comp. Eng., University of Maryland, College Park, MD 20742, United States; Unità di Napoli, INFM, Universita di Napoli, Federico II, I-80125 Napoli, Italy","Bertotti G., IEN Galileo Ferraris, I-10125 Torino, Italy; Mayergoyz I.D., Dept. of Electrical and Comp. Eng., University of Maryland, College Park, MD 20742, United States; Serpico C., Unità di Napoli, INFM, Universita di Napoli, Federico II, I-80125 Napoli, Italy","The problem of magnetization dynamics of a uniformly magnetized uniaxial particle or film, under elliptically polarized applied field, is considered. In the special case of circularly polarized applied field and particles (films) with a symmetry axis, pure time-harmonic magnetization modes exist that can be computed analytically. Deviations from these highly symmetric conditions are treated as perturbation of the symmetric case, The perturbation technique leads to the exactly solvable system of linear differential equations for the perturbations which enables-one to compute higher order magnetization harmonic. The analytical solutions are obtained and then compared with numerical results.","Landau-Lifshitz-Gilbert equation; Magnetization dynamics; Perturbation technique","Differential equations; Isotherms; Magnetic films; Magnetization; Numerical analysis; Perturbation techniques; Polarization; Magnetization dynamics; Magnetic materials","","","","","","","Bertotti G., Serpico C., Mayergoyz I.D., Nonlinear magnetization dynamics under circularly polarized field, Phys. Rev. Lett., 86, (2001); Gurevich A.G., Melkov G.A., Magnetization Oscillations and Waves, (1996); Mayergoyz I.D., Nonlinear Diffusion of Electromagnetic Fields, (1998); Bertotti G., Mayergoyz I.D., Serpico C., Perturbation technique for Landau-Lifshitz-Gilbert equation under elliptically polarized fields, Phys. B, 306, pp. 47-51, (2001)","G. Bertotti; IEN Galileo Ferraris, I-10125 Torino, Italy; email: serpico@unina.it","","Institute of Electrical and Electronics Engineers Inc.","IEEE","2002 International Magnetics Conference (Intermag 2002)","28 April 2002 through 2 May 2002","Amsterdam","60443","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0036762458" +"Shir C.C.","Shir, C.C. (6604086809)","6604086809","Computations of the micromagnetic dynamics in domain walls","1978","Journal of Applied Physics","49","6","","3413","3421","8","41","10.1063/1.325247","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0017982041&doi=10.1063%2f1.325247&partnerID=40&md5=feafb629c74578bdcd9cb8f52c585fcd","IBM Research Laboratory, San Jose, CA 95193, United States","Shir C.C., IBM Research Laboratory, San Jose, CA 95193, United States","A numerical model was developed to compute the temporal and spatial variations of the detailed micromagnetic structures of domain walls by numerical integration of the Landau-Lifshitz-Gilbert equation. The fundamental interactions due to anisotropy, exchange, and demagnetization are included. Preliminary results of the structure of a planar domain wall indicate that the wall width is much larger near the film surface than at the center of the film, because the demagnetization fields are significant near the surface and the side boundaries of the domain wall. The instabilities of the numerical integration of the LLG equation are investigated. Several methods were developed to cope with the stiffness which arises when the damping parameter becomes small. The effects of nondimensional film thickness and anisotropy parameters are similar and are less than 10%, with these parameters varying by a factor of 2. On the other hand, the effects of an ion-implantation layer in the film on the wall structure are found to be very significant.","","MAGNETIC MATERIALS","","","","","","","Landau L., Lifshitz E., Phys. Z. Sowjetunion, 8, (1935); Landau L., Collected Papers of Landau, (1965); Brown W., Magnetostatic Principles in Ferromagnetism, (1962); Brown W., Micromagnetics, (1963); Kittel C., Rev. Mod. Phys, 21, (1949); LaBonte A., J. Appl. Phys, 40, (1969); Tu Y., J. Appl. Phys, 42, (1971); Schlomann E., J. Appl. Phys, 44, (1973); Thiele A., J. Appl. Phys, 45, (1974); Hagedorn F., J. Appl. Phys, 45, (1974); Debonte W., IEEE Trans. Magn, MAG‐11, (1975); Hubert A., J. Appl. Phys, 46, (1975); Walker L., A Treatise on Magnetism, 3, (1963); Slonczewski J., Int. J. Magn, 2, (1972); Slonczewski J., J. Appl. Phys, 44, (1973); Schryer N., Walker L., J. Appl. Phys, 45, (1974); Bourne H., Bartran D., IEEE Trans. Magn, MAG‐8, (1972); Gilbert T.L., Kelly J.K.; Phys. Rev, 100, (1955); Kikuchi R., J. Appl. Phys, 27, (1956); Gillette P., Oshima K., J. Appl. Phys, 29, (1958); Vonsovskii S., Ferromagnetic Resonance, (1966); Sparks M., Ferromagnetic Relaxation Theory, (1964); Lorentz H., The Theory of Electrons, (1952); Toupin R., J. Ration. Mech. Anal, 5, (1956); Willoughby R., Stiff Differential Systems, (1974); Gantmacher F., The Theory of Matrices, 1, (1959); Richtmyer R., Morton K., Difference Methods for Initial‐Value Problems, (1967); Shir C., Henry G.; North J., Wolfe R., Proc. 3rd Int. Conf. on Ion‐Implantation in Semiconductor and Other Materials, (1973); Konishi S., Hsu T., Brown B.; Almasi G., Giess E., Hendel R., Keefe G., Lin Y., Slusarczuk M., AIP Conf. Proc, 24, (1975); Lin Y., Almasi G., Keefe G., IEEE Trans. Magn, MAG‐13, (1977)","","","","","","","","","00218979","","","","English","","Article","Final","","Scopus","2-s2.0-0017982041" +"Ritter J.M.; Palavra A.M.F.; Chai Kao C.P.; Paulaitis M.E.","Ritter, J.M. (57196774564); Palavra, A.M.F. (6701681759); Chai Kao, C.P. (22633793100); Paulaitis, M.E. (7006407814)","57196774564; 6701681759; 22633793100; 7006407814","Three-phase liquid-liquid-gas equilibrium in the ternary system of trans-decalin-n-decane-carbon dioxide","1990","Fluid Phase Equilibria","55","1-2","","173","191","18","11","10.1016/0378-3812(90)85011-X","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0025401549&doi=10.1016%2f0378-3812%2890%2985011-X&partnerID=40&md5=22f70a955ba840656adb857fcfc9bde9","Department of Chemical Engineering, University of Delaware, Newark, DE 19716, United States","Ritter J.M., Department of Chemical Engineering, University of Delaware, Newark, DE 19716, United States; Palavra A.M.F., Department of Chemical Engineering, University of Delaware, Newark, DE 19716, United States; Chai Kao C.P., Department of Chemical Engineering, University of Delaware, Newark, DE 19716, United States; Paulaitis M.E., Department of Chemical Engineering, University of Delaware, Newark, DE 19716, United States","Three-phase, liquid-liquid-gas (LLG) equilibrium behavior was studied for the ternary system trans-decalin-n-decane-CO2. A stoichiometric technique was used to obtain equilibrium phase compositions and molar volumes over a range of temperatures and pressures from the critical point of CO2 to the tricritical point of the ternary mixture. The Peng-Robinson equation of state was found to describe the pressure-temperature (PT) projection of the LLG equilibrium region for this ternary mixture with quantitative accuracy, and provides a reasonable fit of phase compositions and molar volumes. The effects of scaling near mixture critical points and inadequate mixing rules are shown to be the primary limitations to more accurate descriptions of multiphase equilibria. © 1990.","","Carbon Dioxide; Equations of State; Gases - Phase Equilibria; Mathematical Techniques - Error Analysis; Thermodynamics - Mathematical Models; Decane; Equilibrium Phase Decompositions; Liquid Liquid Gas System; Molar Volumes; Ternary System; Trans Decalin; Liquids","","","","","Air Products and Chemical Company; E.I. duPont de Nemours; National Science Foundation, NSF, (CPE 8351228); National Science Foundation, NSF","The authors gratefully acknowledge financial support provided by the National Science Foundation (CPE 8351228) and the following industrial sponsors: Air Products and Chemical Company, E.I. duPont de Nemours","Angus, Armstrong, deReuck, Carbon Dioxide, 3, (1976); Baker, Pierce, Luks, Gibbs Energy Analysis of Phase Equilibria, Society of Petroleum Engineers Journal, (1982); Chai, Ph.D. Thesis, (1981); Davis, Rev. Sci. Instrum., 54, (1983); DiAndreth, Ph.D. Thesis, (1985); DiAndreth, Ritter, Paulaitis, Experimental technique for determining mixture compositions and molar volumes of three or more equilibrium phases at elevated pressures, Industrial & Engineering Chemistry Research, 26, (1987); DiAndreth, Paulaitis, Chem. Eng. Sci., (1989); Fall, Luks, J. Chem. Eng. Data, 31, (1986); Heidemann, Fluid Phase Equilibria, 14, (1983); Heidemann, Khalil, AIChE J., 26, (1980); Hottovy, Kohn, Luks, J. Chem. Eng. Data, 26, (1981); Huie, Luks, Kohn, J. Chem. Eng. Data, 18, (1973); Knobler, Scott, J. Chem. Phys., 73, (1980); Kulkarni, Zarah, Luks, Kohn, J. Chem. Eng. Data, 19, (1974); Kulkarni, Luks, Kohn, J. Chem. Eng. Data, 19, (1974); Leder, Irani, J. Chem. Eng. Data, 20, (1975); Luks, Merrill, Kohn, Fluid Phase Equilibria, 14, (1983); McHugh, Guckes, Macromolecules, 18, (1985); Merrill, Luks, Kohn, J. Chem. Eng. Data, 28, (1983); Mood, Graybill, Boes, Introduction to the Theory of Statistics, (1974); Orr, Taber, Science, 224, (1984); Peng, Robinson, Ind. Eng. Chem. Fundam., 15, (1976); Ritter, Ph.D. Thesis, (1989); Simon, Chemical Engineering at Supercritical Fluid Conditions, (1983); Tiffin, DeVera, Luks, Kohn, J. Chem. Eng. Data, 23, (1978); Tiffin, Guzman, Luks, Kohn, J. Chem. Eng. Data, 23, (1978); Yang, Luks, Kohn, J. Chem. Eng. Data, 21, (1976)","","","","","","","","","03783812","","FPEQD","","English","Fluid Phase Equilib.","Article","Final","","Scopus","2-s2.0-0025401549" +"Hiebert Wayne K.; Ballentine Greg E.; Stankiewicz Andrzej; Freeman Mark R.","Hiebert, Wayne K. (6603628394); Ballentine, Greg E. (6602568780); Stankiewicz, Andrzej (7103189567); Freeman, Mark R. (7402429572)","6603628394; 6602568780; 7103189567; 7402429572","Magnetization reversal dynamics in a permalloy microstructure: time-domain measurement and simulation","2000","Digests of the Intermag Conference","","","","DE","04","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033681016&partnerID=40&md5=b45a79665c69016914c972c3de06cc15","Seagate Technology, Bloomington, United States","Hiebert Wayne K., Seagate Technology, Bloomington, United States; Ballentine Greg E., Seagate Technology, Bloomington, United States; Stankiewicz Andrzej, Seagate Technology, Bloomington, United States; Freeman Mark R., Seagate Technology, Bloomington, United States","An overview is given on the investigation of the reversal dynamics in thin film magnetic samples having lateral dimensions of order of a few micrometer. The dynamics are studied by microscopic measurement using time-resolved scanning Kerr effect microscopy (TR-SKM) and by numerical time-domain simulation using the Landau-Lifshitz-Gilbert (LLG) equation. Initial comparisons between these two methods give reasonably good agreement.","","Computer simulation; Fast Fourier transforms; Kerr magnetooptical effect; Magnetic field effects; Magnetic variables measurement; Magnetization; Metallographic microstructure; Molecular dynamics; Numerical methods; Time domain analysis; Landau-Lifshitz-Gilbert equation; Magnetization reversal dynamics; Permalloy; Static biasing; Time resolved scanning Kerr effect microscopy; Nickel alloys","","","","","","","","","","IEEE","IEEE","2000 IEEE International Magnetics Conference-2000 IEEE INTERMAG","9 April 2000 through 13 April 2000","Toronto, Ont, Can","57511","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0033681016" +"Porter D.G.","Porter, Donald G. (7401830895)","7401830895","Analytical determination of the LLG zero-damping critical switching field","1998","IEEE Transactions on Magnetics","34","4 PART 1","","1663","1665","2","14","10.1109/20.706649","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0032120254&doi=10.1109%2f20.706649&partnerID=40&md5=a5e6c1910c62c6566968ebf8cd623982","Natl. Inst. of Std. and Technology, Gaithersburg, MD 20899, United States","Porter D.G., Natl. Inst. of Std. and Technology, Gaithersburg, MD 20899, United States","Previous numerical studies based on the Landau-Lifshitz-Gilbert (LLG) equation have considered the magnetization reversal of a uniaxial, singledomain particle due to an applied field pulse with a short rise time. When the LLG damping constant α < 1, these studies have observed coherent switching for applied field magnitudes below the StonerWohlfarth limit. The switching field computed in these studies decreases as α → 0, with apparent convergence to a limiting value. In this paper, analytic methods determine the value of the switching field in the zero-damping limit for an applied field pulse with zero rise time. The locus of normalized switching fields in parametric form is hy = -sinθ(cosθ -l)/2; hz = -cosθ(cosθ + l)/2; |θ| < 2π/3. A nonparametric form is also derived. One surprising implication is that magnetization reversal may be caused by an applied field with easy axis component in the same direction as the initial magnetization (hz > 0).","Landau-lifshitz dynamics; Stonerwohlfarth model; Switching field; Zero damping","Magnetic field effects; Magnetic materials; Mathematical models; Particles (particulate matter); Landau-Lifshitz dynamics; Stoner-Wohlfarth model; Magnetization","","","","","","","He L., IEEE Trans. Magn.; Stoner E.G., Wohlfarth E.P., Proc. R. Soc.; Landau L., Lifshitz E., Physikalische Zeitschrift Der Sowjetunion; Gilbert T.L., Physical Review; Gillette P.R., Oshima K., J. Appl. Phys.; He L., Doyle W.D., J. Appl. Phys.; He L., J. Flanders","","","","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-0032120254" +"Grinstein G.; Koch R.H.","Grinstein, G. (22970899100); Koch, R.H. (56246143700)","22970899100; 56246143700","Coarse graining in micromagnetics","2003","Physical Review Letters","90","20","207201","207201/1","207201/4","","76","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0038804008&partnerID=40&md5=45b12b10ebbadf6f38b11dc0fbc422b5","IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, P.O. Box 218, United States","Grinstein G., IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, P.O. Box 218, United States; Koch R.H., IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, P.O. Box 218, United States","The problem of overestimated Curie temperatures is solved by an appeal to the low-temperature renormalization of fixed-length spin models. The main point is that the effective exchange constant of the coarse-grained system experiences a temperature-dependent renormalization, thus producing a phase transition at the proper temperature. Furthermore, it is demonstrated that even at temperatures far below criticality, magnetic properties computed numerically from the LLG equations depend on block size.","","Boundary conditions; Computer simulation; Differential equations; Fourier transforms; Low temperature effects; Magnetic field effects; Magnetic moments; Magnetic variables measurement; Magnetization; Coarse graining; Landau-Lifshitz-Gilbert equations; Micromagnetics; Stratonovich interpretation; Magnetic materials","","","","","","","Weller D., Moser A., IEEE Trans. Magn., 35, (1999); Landau L.D., Lifshitz E.M., Phys. Z. Sowjetunion, 8, (1935); Conger R.L., Essig F.C., Phys. Rev., 104, (1956); Gilbert T.L., Phys. Rev., 100, (1955); Brown W.F., Phys. Rev., 130, (1963); Proceedings of the 44th Annual Conference on Magnetism and Magnetic Materials, San Jose, CA, 1999; Brezin E., Zinn-Justin J., Phys. Rev. Lett., 36, (1976); Brezin E., Zinn-Justin J., Phys. Rev. B, 14, (1976); Nelson D.R., Pelcovits R.A., Phys. Rev. B, 16, (1977); Stratonovich R.L., SIAM J. Control, 4, (1966); Wilson K.G., Kogut J., Phys. Rep., 12 C, (1974); Aharony A., Fisher M.E., Phys. Rev. B, 8, (1973); Pelcovits R.A., Halperin B.I., Phys. Rev. B, 19, (1979); Niemeijer T., Van Leeuwen J.M.J., Phys. Rev. Lett., 31, (1973)","","","American Physical Society","","","","","","00319007","","PRLTA","","English","Phys Rev Lett","Article","Final","","Scopus","2-s2.0-0038804008" +"Fukushima H.; Hayashi N.","Fukushima, Hiroshi (57214204552); Hayashi, Nobuo (35352133200)","57214204552; 35352133200","Computer simulation of magnetization distributions in contiguous-disk bubble devices","1987","IEEE Transactions on Magnetics","23","5","","3364","3366","2","4","10.1109/TMAG.1987.1065592","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0023418954&doi=10.1109%2fTMAG.1987.1065592&partnerID=40&md5=4c5d2fd48a15237607952763f302bc47","Mobara Works, Hitachi, Ltd., Hobara-shi, Chiba 297, Japan; University of Electro-Communications, Chofu-shi, Tokyo 182, Japan","Fukushima H., Mobara Works, Hitachi, Ltd., Hobara-shi, Chiba 297, Japan; Hayashi N., University of Electro-Communications, Chofu-shi, Tokyo 182, Japan","Magnetization distributions in actual contiguous-disk (CD) bubble devices were simulated through numerical integration of the Landau-Lifshitz-Gilbert (LLG) equation with the backward Euler method. Six kinds of energy density terms were included in the LLG equation: Exchange, uniaxial anisotropy, crystalline anisotropy, stress-induced anisotropy, external field, and demagnetizing field. The stress distributions induced in the actual CD pattern were calculated three-dimensionally by means of finite element method on the analogy of thermal-induced stresses. Potential wells calculated from the magnetization distributions were in good agreement with experiments. © 1987 IEEE","","MAGNETIZATION - Computer Simulation; MATHEMATICAL TECHNIQUES - Finite Element Method; CONTIGUOUS-DISK BUBBLE DEVICES; ION-IMPLANTED REGIONS; MGANETIZATION DISTRIBUTIONS; MAGNETIC MATERIALS","","","","","","","Shir C.C., J. Appl. Phy, 49, 3413, (1978); Shiomi S., Shir C.C., J. Appl. Phy, 54, 6847, (1983); Saunders D.A., Kryder K.H., J. Appl. Phys, 57, 4061, (1985); Takeuchi T., Ohta N., Sugita Y., IEEE Trans. Magn, MAG-20, (1984)","","","","","","","","","00189464","","","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0023418954" +"Usatenko O.V.; Chubykalo-Fesenko O.A.; Garcia Sanchez F.","Usatenko, O.V. (6701498194); Chubykalo-Fesenko, O.A. (8264321700); Garcia Sanchez, F. (56321081300)","6701498194; 8264321700; 56321081300","Adiabatic dynamics of small ferromagnetic particles","2005","Journal of Applied Physics","97","10","10A711","","","","1","10.1063/1.1851911","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944443168&doi=10.1063%2f1.1851911&partnerID=40&md5=18ca4ce3df15e2a28692346380476709","Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid, Spain","Usatenko O.V., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid, Spain; Chubykalo-Fesenko O.A., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid, Spain; Garcia Sanchez F., Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid, Spain","The purpose of this work is to present an analytical description of dynamics of small ferromagnetic particles (SFP) with uniaxial anisotropy energy and slowly varying magnetic field applied at an arbitrary angle to it. Theoretical analysis based on the consideration of the Landau-Lifshits-Gilbert (LLG) equation employs an asymptotic expansion similar to the famous semiclassical WKBJ solution of quantum mechanics equations. The small parameter of the expansion is the ratio of characteristic frequency of the applied magnetic field to the precession frequency. The equation describing slow dynamics of SFP is derived. Different cases of slow variation of magnitude and direction of magnetic field are considered. The formal solution of linearized equations is obtained and exact solutions are presented in the cases of magnetic field parallel and perpendicular to the anisotropy axis. © 2005 American Institute of Physics.","","Approximation theory; Differential equations; Equations of motion; Functions; Integral equations; Magnetic anisotropy; Magnetic field effects; Magnetization; Matrix algebra; Quantum theory; Vectors; Linearized equations; Magnetic energy; Magnetization vectors; Uniaxial anisotropy; Ferromagnetic materials","","","","","","","Slichter C.P., Principles of Magnetic Resonance, (1989); Makhnovskiy D.P., Panina V.L., Mapps D.J., Phys. Rev. B, 63, (2001); Bertotti G., Mayergoyz I., Serpico C., J. Appl. Phys., 95, (2004); Berry M.V., J. Phys. a, 18, (1985)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-20944443168" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, Giorgio (7005370974); Mayergoyz, Isaak D. (35495971500); Serpico, Claudio (23013514800)","7005370974; 35495971500; 23013514800","Perturbation technique for LLG equation","2002","Digests of the Intermag Conference","","","","DD09","","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0036913090&partnerID=40&md5=f73ba64c4af6f5af7e305e616457bb98","Istituto Elettrotecnico Nazionale, Galileo Ferraris, I-10135 Torino, Strada delle Cacce 91, Italy; Dept. of Elec. and Computer Eng., University of Maryland, College Park, MD 20742, United States; Dipartimento di Ingegneria Elettrica, Universita di Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy","Bertotti G., Istituto Elettrotecnico Nazionale, Galileo Ferraris, I-10135 Torino, Strada delle Cacce 91, Italy; Mayergoyz I.D., Dept. of Elec. and Computer Eng., University of Maryland, College Park, MD 20742, United States; Serpico C., Dipartimento di Ingegneria Elettrica, Universita di Napoli Federico II, I-80125 Napoli, Via Claudio 21, Italy","The analytical solution of Landau-Lifshitz-Gilbert (LLG) equation was derived by using the rotational invariance of the system with respect to the rotations around the symmetry axis. The approach was based on a two parameters permutation technique that lead to linearized equations for magnetized permutations. The results showed that the permutaion technique was accurate for appreciable deviation from circular polarization of RF fields.","","Ferromagnetism; Linear equations; Magnetization; Perturbation techniques; Magnetization perturbations; Magnetic anisotropy","","","","","","","Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, 6, (2001); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 89, 11, (2001)","G. Bertotti; Istituto Elettrotecnico Nazionale, Galileo Ferraris, I-10135 Torino, Strada delle Cacce 91, Italy; email: bertotti@ien.it","","","IEEE","2002 IEEE International Magnetics Conference-2002 IEEE INTERMAG","28 April 2002 through 2 May 2002","Amsterdam","60350","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0036913090" +"Hertel R.; Wulfhekel W.; Kirschner J.","Hertel, Riccardo (7005476334); Wulfhekel, Wulf (7003623190); Kirschner, Jürgen (7102722482)","7005476334; 7003623190; 7102722482","Domain-wall induced phase shifts in spin waves","2004","Physical Review Letters","93","25","257202","","","","295","10.1103/PhysRevLett.93.257202","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-42749103597&doi=10.1103%2fPhysRevLett.93.257202&partnerID=40&md5=bdec2d71a05b932f0a11dd16bd0e937f","Max-Planck-Inst. F. M., 06120 Halle, Weinberg 2, Germany; Institute of Electronic Properties, Department of Solid State Research, Research Center Jülich, 52425 Jülich, Germany","Hertel R., Max-Planck-Inst. F. M., 06120 Halle, Weinberg 2, Germany, Institute of Electronic Properties, Department of Solid State Research, Research Center Jülich, 52425 Jülich, Germany; Wulfhekel W., Max-Planck-Inst. F. M., 06120 Halle, Weinberg 2, Germany; Kirschner J., Max-Planck-Inst. F. M., 06120 Halle, Weinberg 2, Germany","The interaction between magnetic domain walls and spin waves of ferromagnetic nanoparticles was investigated. The magnetostatic spin waves were found to change their phase as they pass through domain walls, which was revealed by micromagnetic simulations. The magnetization waves were generated in the frequency range of several GHz during the relaxation of the structure towards the ground state. The controlled change of phase of a spin wave is expected to become the operating concept of a new generation of nonvolatile magnetic storage and logical devices. The results show that a significant advantage of a spin-wave based logical signal is the much faster and nondestructive operation mode as compared with a system based on domain-wall motion.","","Anisotropy; Boundary element method; Computer simulation; Damping; Differential equations; Ferromagnetic materials; Finite element method; Integration; Magnetic fields; Magnetization; Magnetostatics; Phase shift; Thin films; Wave propagation; Gyromagnetic ratio; Landau-Lifshitz-Gilbert (LLG) equation; Spin waves; Zeeman energy; Magnetic domains","","","","","","","Wolf S.A., Awschalom D.D., Buhrman R.A., Daughton J.M., Von Molnar S., Roukes M.L., Chtchelkanova A.Y., Treger D.M., Science, 294, (2001); Choi B.C., Belov M., Ballentine G., Freeman M., Phys. Rev. Lett., 86, (2001); Acremann Y., Buess M., Back C.H., Dumm M., Bayreuther G., Pescia D., Nature (London), 414, (2001); Koch R.H., Deak J.G., Abraham W., Trouilloud P.L., Altman R.A., Lu Y., Gallagher W.J., Scheuerlein R., Parkin S.P.P., Phys. Rev. Lett., 81, (1998); Gerrits T., Van Den Berg H., Hohlfeld J., Bar L., Rasing T., Nature (London), 418, (2002); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Hubert A., Schafer R., Magnetic Domains - The Analysis of Magnetic Microstructures, (1998); Wachowiak A., Wiebe J., Bode M., Pietzsch O., Morgenstern M., Wiesendanger R., Science, 298, (2002); Yamasaki A., Wulfhekel W., Hertel R., Suga S., Kirschner J., Phys. Rev. Lett., 91, (2003); Brown Jr. W.F., Micromagnetics, (1963); Kikuchi R., J. Appl. Phys., 27, (1956); Serpico C., Mayergoyz I.D., Bertotti G., J. Appl. Phys., 93, (2003); Hertel R., J. Appl. Phys., 90, (2001); Hindmarsh A.C., Scientific Computing, pp. 55-64, (1983); Schabes M.E., Bertram H.N., J. Appl. Phys., 64, (1988); McMichael R.D., Donahue M.J., IEEE Trans. Magn., 33, (1997); Aharonov Y., Bohm D., Phys. Rev., 115, (1959); Van Oudenaarden A., Devoret M.H., Nazarov Y.V., Mooij J.E., Nature (London), 391, (1998); Rothman J., Klaui M., Lopez-Diaz L., Vaz C.A.F., Bleloch A., Bland J.A.C., Cui Z., Speaks R., Phys. Rev. Lett., 86, (2001); Zhu J.-G., Zheng Y., Prinz G.A., J. Appl. Phys., 87, (2000); Castano F.J., Ross C.A., Frandsen C., Eilez A., Gil D., Smith H., Redjdal M., Humphrey F.B., Phys. Rev. B, 67, (2003); Hannay J.H., J. Phys. A, 18, (1985); Berry M.V., J. Phys. A, 18, (1985); Braun H.-B., Loss D., Phys. Rev. B, 53, (1996); Demokritov S.O., Serga A., Demidov V., Hillebrands B., Kostylev M., Kalinikos B.A., Nature (London), 426, (2003); Slavin A.N., Buttner O., Bauer M., Demokritov S.O., Hillebrands B., Kostylev M.P., Kalinikoe B.A., Grimalsky V.V., Rapoport Y., Chaos, 13, (2003); Serga A.A., Demokritov S.O., Hillebrands B., Min S., Slavin A.N., J. Appl. Phys., 93, (2003); Allwood D.A., Xiong G., Cooke M.D., Faulkner C.C., Atkinson D., Vernier N., Cowburn R., Science, 296, (2002)","R. Hertel; Institute of Electronic Properties, Department of Solid State Research, Research Center Jülich, 52425 Jülich, Germany; email: r.hertel@fz-juelich.de","","","","","","","","00319007","","PRLTA","","English","Phys Rev Lett","Article","Final","","Scopus","2-s2.0-42749103597" +"Hiebert W.K.; Ballentine G.E.; Stankiewicz A.; Freeman M.R.","Hiebert, Wayne K. (6603628394); Ballentine, Greg E. (6602568780); Stankiewicz, Andrzej (7103189567); Freeman, Mark R. (7402429572)","6603628394; 6602568780; 7103189567; 7402429572","Magnetization reversal dynamics in a permalloy microstructure: Time-domain measurement and simulation","2000","Digests of the Intermag Conference","","","","DE","4","","0","10.1109/INTMAG.2000.872095","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-85177143104&doi=10.1109%2fINTMAG.2000.872095&partnerID=40&md5=508f34ef1c8ca6ab7abac28d0804501e","Department of Physics, University of Alberta, Edmonton, T6G 2J1, Canada","Hiebert W.K., Department of Physics, University of Alberta, Edmonton, T6G 2J1, Canada; Ballentine G.E., Department of Physics, University of Alberta, Edmonton, T6G 2J1, Canada; Stankiewicz A., Department of Physics, University of Alberta, Edmonton, T6G 2J1, Canada; Freeman M.R., Department of Physics, University of Alberta, Edmonton, T6G 2J1, Canada","An overview is given on the investigation of the reversal dynamics in thin film magnetic samples having lateral dimensions of order of a few micrometer. The dynamics are studied by microscopic measurement using time-resolved scanning Kerr effect microscopy (TR-SKM) and by numerical time-domain simulation using the Landau-Lifshitz-Gilbert (LLG) equation. Initial comparisons between these two methods give reasonably good agreement.","","","","","","","","","Freeman M.R., J. Appl. Phys., 83, (1998); Stankiewicz A., IEEE Trans. Mag., 134, (1998); Mansuripur M., J. Appl. Phys., 63, (1998); Brankin R.W., RKSUITE, (1992)","","","","","","","","","00746843","","","","English","Dig Intermag Conf","Article","Final","","Scopus","2-s2.0-85177143104" +"Han S.K.; Yu S.-C.; Rao K.V.","Han, Seung Kee (7405943596); Yu, Seong-Cho (7405731022); Rao, K.V. (7404811175)","7405943596; 7405731022; 7404811175","Domain wall jaggedness induced by the random anisotropy orientation in magneto-optic materials: A computer simulation study","1996","Journal of Applied Physics","79","8","","4260","4264","4","3","10.1063/1.361794","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0005614716&doi=10.1063%2f1.361794&partnerID=40&md5=052e29bd7ea92d27e7aabb6271c7d927","Department of Physics, Chungbuk National University, Choengju 360-763, South Korea; Dept. of Condensed Matter Physics, Royal Institute of Technology, S-100 44 Stockholm, Sweden","Han S.K., Department of Physics, Chungbuk National University, Choengju 360-763, South Korea; Yu S.-C., Department of Physics, Chungbuk National University, Choengju 360-763, South Korea, Dept. of Condensed Matter Physics, Royal Institute of Technology, S-100 44 Stockholm, Sweden; Rao K.V., Dept. of Condensed Matter Physics, Royal Institute of Technology, S-100 44 Stockholm, Sweden","Computer simulations of magnetic domain structure in thin films of amorphous rare-earth transition metal magneto-optic recording media are performed. In these simulations, the recording media are two-dimensional lattice of 64×64 magnetic moments with a lattice distance of 10 Å. The motion of the magnetic moments follows the dynamic Landau-Lifshitz-Gilbert (LLG) equation under the influence of an effective field arising from the local anisotropy, nearnest-neighbor exchange, classical dipole-dipole interaction, and an external applied field. Within the constraints of the LLG equation, we have investigated the process of domain wall formation for a medium with random anisotropy orientation. Even for very small randomness of anisotropy orientation, it is found that the 2π-Bloch wall line appears at the boundaries of magnetic domains and the domain wall is jagged. Finally, the effects of exchange stiffness coefficient Ax and anisotropy coefficient Ku on the wall width and the jaggedness which measured the straightness of domain wall are studied. © 1996 American Institute of Physics.","","","","","","","","","Suits J.C., Rugar D., Lin C.J., J. Appl. Phys., 64, (1988); Zeper W.B., Greidanus E.J.A.M., Carcia P.F., Fincher C.R., J. Appl. Phys., 65, (1981); Kryder M.H., J. Appl. Phys., 57, (1985); Bate G., IEEE Trans. Magn. Mater., 54, (1986); Mansuripur M., J. Appl. Phys., 61, (1987); Mansuripur M., Giles R., Comput. Phys., 4, (1990); Mansuripur M., Giles R., Comput. Phys., 5, (1991); Mansuripur M., Giles R., IEEE Trans. Magn. Mater., 24, (1988); Fu H., Giles R., Mansuripur M., Comput. Phys., 8, (1994)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-0005614716" +"Mayergoyz I.D.; Serpico C.; D'Aquino M.; Bertotti G.","Mayergoyz, I.D. (35495971500); Serpico, C. (23013514800); D'Aquino, M. (9732823500); Bertotti, G. (7005370974)","35495971500; 23013514800; 9732823500; 7005370974","Geometrical analysis of precessional switching","2003","Intermag 2003 - Program of the 2003 IEEE International Magnetics Conference","","","1230303","","","","0","10.1109/INTMAG.2003.1230303","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84949498069&doi=10.1109%2fINTMAG.2003.1230303&partnerID=40&md5=c68c9f25c0fa3494bd158d3a8e6ea915","Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States; Department of Electrical Engineering, Università di Napoli Federico II, Via Claudio 21, Napoli, I-80125, Italy; Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, Strada delle Cacce, 91, Torino, I-10135, Italy","Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, 20742, MD, United States; Serpico C., Department of Electrical Engineering, Università di Napoli Federico II, Via Claudio 21, Napoli, I-80125, Italy; D'Aquino M., Department of Electrical Engineering, Università di Napoli Federico II, Via Claudio 21, Napoli, I-80125, Italy; Bertotti G., Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, Strada delle Cacce, 91, Torino, I-10135, Italy","In this paper we present a magnetization switching in magnetic particles and films. It is one of the fundamental issues in spin dynamics studies due to its relevance in magnetic recording and data storage technology. In this area it has been recently recognized the potential convenience of realizing the switching of magnetization in particles and film by means of precessional motion of magnetization. In the typical precessional switching process the magnetization is initially along the easy axis of the body and the external magnetic field is approximately orthogonal to the easy axis. If the field is strong enough and applied for a sufficiently long time, the magnetization can be reversed. We will study this process by using the Landau-Lifshitz-Gilbert (LLG) equation. © 2003 IEEE.","Educational institutions; Integral equations; Magnetic anisotropy; Magnetic films; Magnetic particles; Magnetic recording; Magnetic switching; Magnetization; Memory; Perpendicular magnetic anisotropy","Anisotropy; Data storage equipment; Digital storage; Electromagnetic field effects; Integral equations; Magnetic films; Magnetic recording; Magnetic storage; Magnetism; Magnetization; Spin dynamics; Switching; Data storage technology; Educational institutions; External magnetic field; Landau-Lifshitz-Gilbert equations; Magnetic particle; Magnetic switching; Perpendicular magnetic anisotropy; Precessional switching process; Magnetic anisotropy","","","","","","","Mallinson J.C., IEEE Transactions on Magnetics, 36, 4, (2000); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Phys. Rev. B, 61, (2000); Kaka S., Russek S.E., Appl. Phys. Lett., 80, (2002)","","","Institute of Electrical and Electronics Engineers Inc.","Magnetics Society of the Institute of Electrical and Electronics Engineers","2003 IEEE International Magnetics Conference, Intermag 2003","30 March 2003 through 3 April 2003","Boston","114081","","0780376471; 978-078037647-2","","","English","Intermag - Program IEEE Int. Magn. Conf.","Conference paper","Final","","Scopus","2-s2.0-84949498069" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, Giorgio (7005370974); Mayergoyz, Isaak D. (35495971500); Serpico, Claudio (23013514800)","7005370974; 35495971500; 23013514800","Critical Fields and Pulse Durations for Precessional Switching of Thin Magnetic Films","2003","IEEE Transactions on Magnetics","39","5 II","","2504","2506","2","16","10.1109/TMAG.2003.816454","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0141953874&doi=10.1109%2fTMAG.2003.816454&partnerID=40&md5=d7ba670100bfa8f2162eeab94310153f","Ist. Elettrotecn. Naz. Galileo F., 10135 Turin, Italy; Department of Electrical Engineering, University of Maryland, College Park, MD 20742, United States; Department of Electrical Engineering, Univ. di Napoli Federico II, 80125 Naples, Italy","Bertotti G., Ist. Elettrotecn. Naz. Galileo F., 10135 Turin, Italy; Mayergoyz I.D., Department of Electrical Engineering, University of Maryland, College Park, MD 20742, United States; Serpico C., Department of Electrical Engineering, Univ. di Napoli Federico II, 80125 Naples, Italy","The precessional switching process of a uniformly magnetized thin film with in-plane anisotropy subject to pulsed magnetic fields applied in the film plane is analyzed. Critical fields required to achieve switching are studied for the case when the applied field is constant during the pulse duration and forms arbitrary angles with the hard axis. By using two integrals of magnetization motion, the explicit expressions for the critical field are derived. The formulas for durations of rectangular magnetic field pulses that guarantee the precessional switching of magnetization are presented as well.","Critical fields; Landau-Lifshitz-Gilbert (LLG) equation; Magnetization switching; Precessional switching","Magnetic anisotropy; Magnetic fields; Magnetization; Switching; Precessional switching; Magnetic thin films","","","","","MIUR-FIRB, (RBAU01B2T8); U.S. Department of Energy, USDOE","Manuscript received January 13, 2003. This work was supported in part by the U.S. Department of Energy and by the Italian MIUR-FIRB under Contract RBAU01B2T8. G. Bertotti is with the Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, 10135 Turin, Italy. I. D. Mayergoyz is with the Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742 USA. C. Serpico is with the Department of Electrical Engineering, Università di Napoli Federico II, 80125 Naples, Italy (email: serpico@unina.it). Digital Object Identifier 10.1109/TMAG.2003.816454","Schumacher H.W., Chappert C., Crozat P., Sousa R.C., Freitas P.P., Miltat J., Ferre J., Precessional magnetization reversal in microscopic spin valve cells, IEEE Trans. Magn., 38, pp. 2480-2483, (2002); Kaka S., Russek S.E., Precessional switching of submicrometer spin valves, Appl. Phys. Lett., 80, pp. 2958-2960, (2002); Bauer M., Fassbender J., Hillebrands B., Stamps R.L., Switching behaviour of a Stoner particle beyond the relaxation time limit, Phys. Rev. B, 61, pp. 3410-3416, (2000); Bertotti G., Mayergoyz I.D., Serpico C., D'Aquino M., Geometrical analysis of precessional switching and relaxation in uniformly magnetized bodies, IEEE Trans. Magn., 39, pp. 2501-2503, (2003); Porter D.G., Analytical determination of the LLG zero-damping critical switching field, IEEE Trans. Magn., 34, pp. 1663-1665, (1998)","G. Bertotti; Ist. Elettrotecn. Naz. Galileo F., 10135 Turin, Italy; email: serpico@unina.it","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0141953874" +"Khapikov A.","Khapikov, Andrci (6701650565)","6701650565","Classical spin as a nonlinear damped oscillator","2003","Digests of the Intermag Conference","","","","GR08","","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0141788962&partnerID=40&md5=4849f0f5fd40d97514ca5aab3d9bf51d","Read-Rite Corporation, Fremont, CA 94539, 44100 Osgood Road, United States","Khapikov A., Read-Rite Corporation, Fremont, CA 94539, 44100 Osgood Road, United States","The classical spin as a nonlinear damped oscillator was discussed. It was found that the damping was described by a single scalar Gilbert parameter indicating that in the linear approximation, this equation coincided with the linearized micromagnetic LLG equation. An expression for the one-dimensional energy barrier was also presented.","","Ferromagnetism; Magnetic anisotropy; Magnetic films; Magnetization; Magnetic noise; Oscillators (electronic)","","","","","","","Safonov V.L., Bertram H.N., Phys. Rev. B, 60, (2002); Smith N., J. Appl. Phys., 92, (2002)","","","","Magnetics Society of the IEEE","Intermag 2003: International Magnetics Conference","28 March 2003 through 3 April 2003","Boston, MA","61560","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0141788962" +"Deak J.G.","Deak, James G. (7005123422)","7005123422","Finite temperature micromagnetics and magnetic measurements of submicron patterned permalloy thin films","2003","Journal of Applied Physics","93","10 2","","6814","6816","2","5","10.1063/1.1555334","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0038314419&doi=10.1063%2f1.1555334&partnerID=40&md5=ed78b5b561c3d2e8428c91bc08701b86","Micron Technology, Inc., R and D, Boise, ID 83707, United States","Deak J.G., Micron Technology, Inc., R and D, Boise, ID 83707, United States","The necessity of stochastic micromagnetic simulation for accurate prediction of coercivity of submicron patterned thin films was discussed. The application of Landu-Lifshitz-Gilbert (LLG) equation was not sufficient for prediction of coercivity of the films. The importance of the second-order Heun scheme for the purpose was indicated by the direct comparison of measurements of the coercivity of arrays of submicron patterned thin films with simulation.","","Coercive force; Ferromagnetic materials; Magnetic fields; Magnetic variables measurement; Magnetization; Thermal effects; Micromagnetics; Magnetic thin films","","","","","","","Brown W.F. Jr., Micromagnetics, (1978); Mansuripur M., J. Appl. Phys., 63, (1988); Zhu J.-G., Bertram H.N., J. Appl. Phys., 63, (1988); Shi J., Li J., Tehrani S., J. Appl. Phys., 91, (2002); Rizzo N., Deherrera M., Janesky J., Engel B., Slaughter J., Tehrani S., Appl. Phys. Lett., 80, (2002); Cullity B.D., Introduction to Magnetic Materials, pp. 410-422, (1972); Brown W.F., Phys. Rev., 130, (1963); IEEE Trans. Magn., 15, (1979); Koch R.H., Deak J.G., Grinstein G., Appl. Phys. Lett., 75, (1999); Zhu J.-G., J. Appl. Phys., 91, (2002); Garcia-Palacios J.L., Lazaro F.J., Phys. Rev. B, 58, (1998); Scholz W., Schrefl T., Fidler J., J. Magn. Magn. Mater., 223, (2001); Donahue M.J., J. Appl. Phys., 83, (1998); McMichael R.D., Donahue M.J., Porter D.G., Eicke J., J. Appl. Phys., 89, (2001); Gonzalez R., Woods R., Digital Image Processing, (2002); Bhattacharyya M., Anthony T., Nickel J., Sharma M., Tran L., Walmsley R., IEEE Trans. Magn., 37, (2001); Grinstein G., Koch R.H.","J.G. Deak; Micron Technology, Inc., R and D, Boise, ID 83707, United States; email: jgdeak@micron.com","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-0038314419" +"Serpico C.; Bertotti G.; D'Aquino M.; Bonin R.; Mayergoyz I.D.","Serpico, C. (23013514800); Bertotti, G. (7005370974); D'Aquino, M. (9732823500); Bonin, R. (9736915400); Mayergoyz, I.D. (35495971500)","23013514800; 7005370974; 9732823500; 9736915400; 35495971500","Transient dynamics leading to self-oscillations in nanomagnets driven by spin-polarized currents","2005","IEEE Transactions on Magnetics","41","10","","3100","3102","2","4","10.1109/TMAG.2005.855235","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-27744547270&doi=10.1109%2fTMAG.2005.855235&partnerID=40&md5=7707df2a534c95b3e256cee2198e77ca","Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, 1-80125 Napoli, Italy; Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, 10135 Torino, Italy; Istituto Elettrotecnico Nazionale Galileo Ferraris, 1-10135 Torino, Italy; Politecnico di Torino, Torino 1-10129, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States","Serpico C., Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, 1-80125 Napoli, Italy; Bertotti G., Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, 10135 Torino, Italy; D'Aquino M., Dipartimento di Ingegneria Elettrica, Università degli Studi di Napoli Federico II, 1-80125 Napoli, Italy; Bonin R., Istituto Elettrotecnico Nazionale Galileo Ferraris, 1-10135 Torino, Italy, Politecnico di Torino, Torino 1-10129, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States","Magnetization dynamics in uniformly magnetized nanomagnets subject to spin-polarized currents is studied by Landau-Lifshitz-Gilbert (LLG) equation with a spin-transfer torque term. This kind of magnetic system may exhibit stationary states and self-oscillatory regimes. By using the fact that spin-transfer torque and Gilbert damping are small perturbations of the conservative LLG dynamics, the analysis of self-oscillations is carried out by an appropriate perturbation technique. Averaging technique is then used to derive an approximated model for the energy dynamics which enables one to study the transient leading to self-oscillatory regimes. The accuracy of the proposed analytical technique is tested by comparison with numerical solutions of the LLG equation. © 2005 IEEE.","Landau-Lifshitz-Gilbert (LLG) equation; Magnetization dynamics; Self-oscillations; Spin-transfer torque","Damping; Electric currents; Electromagnetic wave polarization; Magnetization; Oscillations; Perturbation techniques; Torque; Transients; Landau-Lifshtiz-Gilbert (LLG) equation; Magnetization dynamics; Self-oscillations; Spin-transfer torque; Magnets","","","","","MIUR-FIRB, (RBAU01B2T8)","This work was supported in part by the Italian MIUR-FIRB under Contract RBAU01B2T8 and in part by the ISI Lagrange Fellow Program.","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Rippard W.H., Et al., Phys. Rev. Lett., 92, (2004); Kiselev S.I., Et al., Nature, 425, (2003); Bertotti G., Et al., Phys Rev. Lett., 94, (2005); Perko L., Differential Equations and Dynamical Systems, (1996); Bertotti G., Et al., Phys. B, 343, (2004); Hancock H., Elliptic Integrals, (1917); Bertotti G., Et al., J. Appl. Phys., 95, (2004)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-27744547270" +"Bertotti G.; Mayergoyz I.D.; Serpico C.","Bertotti, G. (7005370974); Mayergoyz, I.D. (35495971500); Serpico, C. (23013514800)","7005370974; 35495971500; 23013514800","Spin-wave instabilities in Landau-Lifshitz-Gilbert dynamics","2001","Physica B: Condensed Matter","306","1-4","","106","111","5","3","10.1016/S0921-4526(01)00987-5","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0035576390&doi=10.1016%2fS0921-4526%2801%2900987-5&partnerID=40&md5=e125107ad856619c80a705b0e89b7766","Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, I-10125 Torino, Corso Massimo, D'Azeglio 42, Italy; Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; INFM, Department of Electrical Engineering, Università Di Napoli Federico II, I-80125 Napoli, via Claudio 21, Italy","Bertotti G., Istituto Elettrotecnico Nazionale (IEN) Galileo Ferraris, I-10125 Torino, Corso Massimo, D'Azeglio 42, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742, United States; Serpico C., INFM, Department of Electrical Engineering, Università Di Napoli Federico II, I-80125 Napoli, via Claudio 21, Italy","The stability of large rotationally invariant magnetization motions is analytically studied. By using the analytical form of rotationally invariant solutions of the Landau-Lifshitz-Gilbert (LLG) equation and by performing the perturbation analysis around these solutions, spin-wave instability conditions valid for arbitrary frequencies and amplitudes of the driving RF field are derived. It is demonstrated that sufficiently large magnetization motions are always stable with respect to spin-wave perturbations. It is also demonstrated that the occurrence of spin-wave instability of spatially uniform large scale magnetization dynamics may depend on history of its formation. © 2001 Elsevier Science B.V. All rights reserved.","Landau-Lifshitz-Gilbert equation; Spin-wave; Stability","Ferromagnetic resonance; Perturbation techniques; Radio waves; Spin waves; Magnetization","","","","","U.S. Department of Energy, USDOE","This work was supported by the US Department of Energy, Engineering Research Program.","Suhl H., Proc. IRE, 44, (1956); Suhl H., J. Phys. Chem. Solids, 1, (1957); Wigen P.E., Nonlinear Phenomena and Chaos in Magnetic Materials, (1994); Suhl H., Zhang X.Y., Phys. Rev. Lett., 57, (1986); McMichael R.D., Wigen P.E., Phys. Rev. Lett., 64, (1990); Bertotti G., Serpico C., Mayergoyz I.D., Phys. Rev. Lett., 86, (2001); Callen H.B., J. Phys. Chem. Solids, 4, (1958); Suhl H., IEEE Trans. Magn., 34, (1998); Arnold V.I., Mathematical Methods of Classical Mechanics, (1989); Seagle D.J., Charap S.H., Artman J.O., J. Appl. Phys., 57, (1985); Fetisov Y.K., Patton C.E., Sygonach V.T., IEEE Trans. Magn., 35, (1999)","G. Bertotti; IEN Galileo Ferraris, I-10125 Torino, Corso Massimo, D'Azeglio 42, Italy; email: bertotti@ien.it","","","","3th International Symposium on Hysteresis (HMM 2001)","23 May 2001 through 23 May 2001","Ashburn, VI","58904","09214526","","PHYBE","","English","Phys B Condens Matter","Conference paper","Final","","Scopus","2-s2.0-0035576390" +"Braselton J.P.; Abell M.L.; Braselton L.M.","Braselton, James P. (6603958372); Abell, Martha L. (7005343030); Braselton, Lorraine M. (6505959740)","6603958372; 7005343030; 6505959740","Schryer-Walker quasi-exact solutions to the Landau-Lifshitz-Gilbert equations","2001","Applied Mathematics and Computation","124","2","","151","167","16","0","10.1016/S0096-3003(00)00083-7","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-23644437157&doi=10.1016%2fS0096-3003%2800%2900083-7&partnerID=40&md5=ac1f99a24f7e5780121ecc444195cca0","Department of Mathematics and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P. O. Box 8093, United States","Braselton J.P., Department of Mathematics and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P. O. Box 8093, United States; Abell M.L., Department of Mathematics and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P. O. Box 8093, United States; Braselton L.M., Department of Mathematics and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P. O. Box 8093, United States","The Landau-Lifshitz-Gilbert (LLG) equations describe the dynamics of ferromagnets. Using various assumptions, several exact solutions to this nonlinear system are determined in Refs. [Phys. Rev. Lett. 65 (1990) 787; J.F. Dillon, Domains and domain walls, in: G.T. Rado, H. Suhl (Eds.), A Treatise on Modern Theory and Materials. Vol. 3: Magnetism, Academic Press, New York, 1963; J. Nonlinear Mech. 36(4) (2001) 571; J. Appl. Phys. 45 (1974) 5406; Phys. Rev. B 43 (1991) 5908]. This paper generalizes these previous results and develops several quasi-exact solutions. The accuracy of these quasi-exact solutions is illustrated in several examples. © 2001 Elsevier Science Inc. All rights reserved.","Landau-Lifshitz-Gilbert equations; Magnetization; Nonlinear system of partial differential equations; Partial differential equations (nonlinear system of)","Ferromagnetic materials; Magnetization; Nonlinear systems; Partial differential equations; Domain walls; Landau-Lifshitz-Gilbert (LLG) equations; Nonlinear equations","","","","","","","Broz J.S., Braun H.B., Brodbeck O., Baltensperger W., Helman J.S., Nucleation of magnetization reversal via creation of pairs of bloch walls, Phys. Rev. Lett., 65, pp. 787-789, (1990); Dillon J.F., Domains and domain walls, A Treatise on Modern Theory and Materials. Vol. 3: Magnetism, 3, (1963); Braselton J.P., Abell M.L., Braselton L.M., Generalized Walker solutions to the Landau-Lifshitz-Gilbert equations, J. Nonlinear Mech., 36, 4, (2001); Schryer N.L., Walker I.R., The motion of 180° domain walls in uniform dc magnetic fields, J. Appl. Phys., 45, pp. 5406-5421, (1974)","J.P. Braselton; Department of Mathematics and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P. O. Box 8093, United States; email: jimbras@gsvms2.cc.gasou.edu","","Elsevier Inc.","","","","","","00963003","","AMHCB","","English","Appl Math Comput","Article","Final","","Scopus","2-s2.0-23644437157" +"Greaves S.J.; Muraoka H.; Sugita Y.; Nakamura Y.","Greaves, S.J. (7006831295); Muraoka, H. (12756598400); Sugita, Y. (7202641233); Nakamura, Y. (55624471280)","7006831295; 12756598400; 7202641233; 55624471280","Thermal bit-writing dynamics in magneto-optic recording media","1999","Digests of the Intermag Conference","","","","GE","04","","0","10.1109/intmag.1999.837875","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0033299834&doi=10.1109%2fintmag.1999.837875&partnerID=40&md5=0245f091a9cab8253712747f7591b295","Tohoku Univ, Sendai, Japan","Greaves S.J., Tohoku Univ, Sendai, Japan; Muraoka H., Tohoku Univ, Sendai, Japan; Sugita Y., Tohoku Univ, Sendai, Japan; Nakamura Y., Tohoku Univ, Sendai, Japan","The magnetization reversal dynamics in perpendicular recording media were studied using a model based on the Landau-Lifshitz-Gilbert (LLG) equation. By assigning a discrete value of temperature to each individual cell in the model, the recording process in the magneto-optic media was successfully simulated.","","Computer simulation; Heat conduction; Magnetic fields; Magnetization; Magnetooptical effects; Mathematical models; Temperature; Curie temperature; Landau-Lifshitz-Gilbert equation; Magnetization reversal dynamics; Magnetooptic recording; Perpendicular recording; Thermal bit writing dynamics; Magnetic recording","","","","","","","","","","IEEE","","Proceedings of the 1999 IEEE International Magnetics Conference 'Digest of Intermag 99'","18 May 1999 through 21 May 1999","Kyongju, South Korea","55655","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0033299834" +"Samuel Jiang M.J.; Kaper H.G.; Leaf G.K.","Samuel Jiang, Magnets J. (14056962500); Kaper, Hans G. (7004080202); Leaf, Gary K. (56977264100)","14056962500; 7004080202; 56977264100","Hysteresis in layered spring","2001","Discrete and Continuous Dynamical Systems - Series B","1","2","","219","232","13","20","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-33746686374&partnerID=40&md5=94a5e3c7b9f90d8c2b37d4618d3a4c4a","Materials Science, Division Argonne National Laboratory, Argonne, IL GO-139, United States; Mathematics and Computer Science, Division Argonne National Laboratory, Argonne, IL C0439, United States; Mathematics and Computer Science, Division Argonne National Laboratory, Argonne, IL 60439, United States","Samuel Jiang M.J., Materials Science, Division Argonne National Laboratory, Argonne, IL GO-139, United States; Kaper H.G., Mathematics and Computer Science, Division Argonne National Laboratory, Argonne, IL C0439, United States; Leaf G.K., Mathematics and Computer Science, Division Argonne National Laboratory, Argonne, IL 60439, United States","This article addresses a problem of micromagnetics: the reversal of magnetic moments in layered spring magnets. A one-dimensional model is used of a film consisting of several atomic layers of a soft material on top of several atomic layers of a hard material. Each atomic layer is taken to be uniformly magnetized, and spatial inhomogeneities within an atomic layer are neglected. The state of such a system is described by a chain of magnetic spin vectors. Each spin vector-behaves like a spinning top driven locally by the effective magnetic field and subject to damping (Landau-Lifshitz-Gilbert equation). A numerical integration scheme for the LLG equation is presented that is unconditionally stable and preserves the magnitude of the magnetization vector at all times. The results of numerical investigations for a bilayer in a rotating in-plane magnetic field show hysteresis with a basic period of 2?r at moderate fields and hysteresis with a basic period of v at strong fields.","Hysteresis; Landau-lifshitz-gilbert equation; Micromagnetics; Spring magnets","","","","","","","","Kneller E.F., Hawig R., THE EXCHANGE-SPRING MAGNET: a NEW MATERIAL PRINCIPLE for PERMANENT MAGNETS, IEEE Trans. Mag., 27, pp. 3588-3600, (1991); Coey J.M.D., Skomski R., NEW MAGNETS from INTERSTITIAL INTERMETALLICS, Physica Scripta, T, 49, pp. 315-321, (1993); Skomski R., Coey J.M.D., GIANT ENERGY PRODUCT in NANOSTRUCTURED TWO-PHASE MAGNETS, Phys. Rev. B, 48, pp. 15812-15816, (1993); Fischer R., Leinewebber T., Kronmuller H., FUNDAMENTAL MAGNETIZATION PROCESSES in NANOSCALED COMPOSITE PERMANENT MAGNETS, Phys. Rev. B, 57, pp. 10723-10732, (1998); Fullerton E.E., Jiang J.S., Sowers C.H., Pearson J.E., Bader S.D., STRUCTURE and MAGNETIC PROPERTIES of EXCHANGE-SPRING SM-CO/CO SUPERLATTICES, Appl. Phys. Lett., 72, pp. 380-382, (1998); Jiang J.S., Fullerton E.E., Sowers C.H., Inomata A., Bader S.D., Shapiro A.J., Shull R.D., Gornakov V.S., Nikitenko V.I., ""Spring magnet films,"" IEEE Trans. Magn., 35, pp. 3229-3234, (2000); Landau L., Lifshitz E., ON the THEORY of MAGNETIC PERMEABILITY in FERROMAGNETIC BODIES, Physik. Z. Soviet Union, 8, pp. 153-169, (1935); Gilbert T.L., A LAGRANGIAN FORMULATION of GYROMAGNETIC EQUATION of the MAGNETIZATION FIELD, Phys. Rev., 100, (1955); Fidler J., Schrefl T., MICROMAGNETIC MODELING-THE CURRENT STATE of the ART, J. Phys. D: Appl. Phys., 33, (2000); David S., Parkin S.S.P., Fullerton E.E., Platt C., Berkowitz A., Jiang J.S., D.bader S., FIELD DEPENDENT REVERSAL MODES in EXCHANGE-SPRING THIN FILMS from ROTATIONAL HYSTERESIS ANALYSIS, J. Appl. Phys.; Shull R.D., Shapiro A.J., Gornakov V.S., Nikitenko V.I., Jiang J.S., Kaper H.G., Leaf G.K., Bader S.D., SPIN SPRING BEHAVIOR in EXCHANGE COUPLED SOFT and HIGIICOERCIVITY HARD FERROMAGNETS, J. Appl. Phys. (To Appear).; Jiang J.S., Kaper H.G., Leaf G.K., NUMERICAL SIMULATIONS of MAGNETIC REVERSAL in LAYERED SPRING MAGNETS, ANL/MCS-TM-247, Argprine National Laboratory; January, (2001); Bertram H.N., ""Theory of Magnetic Recording,"" Cambridge University Press, (1994); Nigam N., EFFICIENT MICROMAGNETIC CALCULATIONS, Third SIAM Conf. on Mathematical Aspects of Materials Science, Philadelphia, Pennsylvania; May, (2000); Weinan E., Wang X.P., NUMERICAL METHODS for the LANDAU-LIFSHITZ EQUATION, SIAM J. Numer. Anal, (To Appear).","","","","","","","","","15313492","","","","English","Discrete Contin. Dyn. Syst. Ser. B","Article","Final","","Scopus","2-s2.0-33746686374" +"Suess D.; Schrefl T.; Fidler J.","Suess, D. (7004076065); Schrefl, T. (7005780657); Fidler, J. (35601590600)","7004076065; 7005780657; 35601590600","Reversal modes, thermal stability and exchange length in perpendicular recording media","2001","IEEE Transactions on Magnetics","37","4 I","","1664","1666","2","22","10.1109/20.950931","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0035386551&doi=10.1109%2f20.950931&partnerID=40&md5=d0f8302c0b6a802387e88ac7aa5b557e","Inst. of Applied and Tech. Physics, Vienna University of Technology, A-1040 Vienna, Wiedner Hauptstr. 8-10, Austria","Suess D., Inst. of Applied and Tech. Physics, Vienna University of Technology, A-1040 Vienna, Wiedner Hauptstr. 8-10, Austria; Schrefl T., Inst. of Applied and Tech. Physics, Vienna University of Technology, A-1040 Vienna, Wiedner Hauptstr. 8-10, Austria; Fidler J., Inst. of Applied and Tech. Physics, Vienna University of Technology, A-1040 Vienna, Wiedner Hauptstr. 8-10, Austria","Micromagnetic simulations are performed to investigate the reversal process and the thermal stability of a grain of a typical perpendicular recording media (Co-Cr). The integration of the LLG equation yields that the reversal process changes slowly and steadily from coherent rotation to nucleation with increasing column length. The region between homogeneous rotation and nucleation becomes smaller and is shifted to smaller column lengths if the damping constant is reduced from α = 1 to α = 0.02. In the weakly damped case very fast switching modes exist if the switching field is only slightly larger than the coercive field. In this small regime the switching time increases with higher switching fields. Using solutions of LLG simulations, energy barriers between the two stable states at zero field are estimated. For column lengths larger than 30 nm the energy barrier for inhomogeneous reversal processes are smaller than for coherent rotation.","Energy barriers; Fast switching; Micromagnetics; Perpendicular recording; Thermal stability","Coercive force; Computer simulation; Damping; Magnetization; Nucleation; Switching; Thermodynamic stability; Micromagnetic simulations; Magnetic recording","","","","","Austrian Science Fund, FWF, (P13260, Y132-PHY)","Manuscript received October 13, 2000. This work was supported by the Austrian Science Fund (P13260 and Y132-PHY). D. Suess is with the Institute of Applied and Technical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna, Austria (e-mail: suess@magnet.atp.tuwien.ac.at). T. Schrefl (e-mail: thomas.schrefl@tuwien.ac.at). J. Fidler (e-mail: fidler@email.tuwien.ac.at). Publisher Item Identifier S 0018-9464(01)07298-3.","Richter H.J., Recent advances in the recording physics of thin-film media, J. Phys. D: Appl. Phys., 32, pp. 147-168, (1999); Fidier J., Schrefl T., Micromagnetic modeling-the current state of the art, J. Phys. D, 33, 15, pp. 135-156, (2000); Mills G., Jonson H., Quantum and thermal effects in H2 dissociative adsorption: Evaluation of free energy barriers in multidimensional quantum systems, Phys. Rev. Lett., 72, 7, pp. 1124-1127, (1994); Braun H.B., Nucleation in ferromagnetic nanowires-magnetostatics and topology, J. Appl. Phys., 85, pp. 6172-6174, (1999)","D. Suess; Inst. of Applied and Tech. Physics, Vienna University of Technology, A-1040 Vienna, Wiedner Hauptstr. 8-10, Austria; email: suess@magnet.atp.tuwien.ac.at","","Institute of Electrical and Electronics Engineers Inc.","","8th Joint Magnetism and Magnetic Materials -International Magnetic Conference- (MMM-Intermag)","7 January 2001 through 11 January 2001","San Antonio, TX","58692","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-0035386551" +"Liu J.F.; Vora P.; Walmer M.H.; Kottcamp E.; Bauser S.A.; Higgins A.; Liu S.","Liu, J.F. (57196293855); Vora, P. (9247982600); Walmer, M.H. (6603709054); Kottcamp, E. (8608124600); Bauser, S.A. (6506679944); Higgins, A. (9247982700); Liu, S. (7409456959)","57196293855; 9247982600; 6603709054; 8608124600; 6506679944; 9247982700; 7409456959","Microstructure and magnetic properties of sintered NdFeB magnets with improved impact toughness","2005","Journal of Applied Physics","97","10","10H101","","","","42","10.1063/1.1847215","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944449400&doi=10.1063%2f1.1847215&partnerID=40&md5=fb77c1beb260388cd0468d9e2920cf06","Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; University of Dayton, Dayton, OH 45469, 300 College Park, United States","Liu J.F., Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; Vora P., Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; Walmer M.H., Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; Kottcamp E., Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; Bauser S.A., University of Dayton, Dayton, OH 45469, 300 College Park, United States; Higgins A., University of Dayton, Dayton, OH 45469, 300 College Park, United States; Liu S., University of Dayton, Dayton, OH 45469, 300 College Park, United States","An effort to increase the impact toughness of Nd-Fe-B sintered magnets by adding small amounts of Al, Nd, Ga, Cu, and Nb was successful. No significant compromise to magnetic properties occurred. Based on this work, a series of sintered Nd-Fe-B magnets with improved toughness was developed, which we call ToughNEO™. Small precipitates, which may contribute to the improvement of toughness, were observed using scanning electron microscope for all samples with improved toughness. Tumbling and drilling tests further verified the improved toughness of these developed ToughNEO™ magnets. © 2005 American Institute of Physics.","","Computer simulation; Data storage equipment; Magnetic materials; Rotation; Signal to noise ratio; White noise; Landau-Lifshitz-Gilbert (LLG) equation; Micromagnetic simulation; Soft underlayer (SUL); Thermal fluctuations; Magnetic recording","","","","","Office of Naval Research, ONR","The financial support for this study by the Office of Naval Research (ONR) is gratefully acknowledged.","Liu J.F., McGinnis K., Kottcomp E., Walmer M.H., Bauser S., Higgins A., Liu S., 18th International Workshop on High Performance Magnets and Their Applications, (2004); Liu S., Cao D., Leese R., Bauser S., Kuhl G.E., Liu J.F., Walmer M.H., Kottcamp E., Proceedings of the 17th International Workshop on RE Magnets and Their Applications, pp. 360-371, (2002); Withey P.A., Kennett H.M., Bowen P., Harris I.R., IEEE Trans. Magn., 26, (1990); Horton J.A., Wright J.L., Herchenroeder J.W., IEEE Trans. Magn., 32, (1996); De Groot C.H., Buschow K.H.J., De Boer F.R., De Kort K., J. Appl. Phys., 83, (1998)","Electron Energy Corporation, Landisville, PA 17538, 924 Links Avenue, United States; email: jfl@electronenergy.com","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-20944449400" +"Nakatani R.; Takahashi N.; Yoshida T.; Yamamoto M.","Nakatani, Ryoichi (7005234924); Takahashi, Noritsugu (55454980800); Yoshida, Tetsuo (55700666200); Yamamoto, Masahiko (57297230700)","7005234924; 55454980800; 55700666200; 57297230700","Magnetic states and magnetization processes of Ni-Fe/Hf annular dots as candidates of non-volatile memory cells","2002","Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers","41","12","","7359","7366","7","5","10.1143/jjap.41.7359","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0036994907&doi=10.1143%2fjjap.41.7359&partnerID=40&md5=2d4862b48c81e3172c888f7d6088d357","Dept. Mat. Science and Engineering, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan","Nakatani R., Dept. Mat. Science and Engineering, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan; Takahashi N., Dept. Mat. Science and Engineering, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan; Yoshida T., Dept. Mat. Science and Engineering, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan; Yamamoto M., Dept. Mat. Science and Engineering, Graduate School of Engineering, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan","We have investigated Ni-Fe/Hf annular dots that have closed magnetic circuits as candidates of non-volatile magnetic memory cells. The shapes of the annular dots are circular, square and triangular. We have also investigated ordinary circular, square and triangular dots for comparison. The circular annular dots and the triangular annular dots have the vortical magnetic configurations whose magnetizations are along the sides of the annular dots. On the other hand, the circular dots have the vortex configurations whose cores are at the center of the circular dots. The square annular dots, the square dots and the triangular dots have complicated domain structures. The images of magnetic force microscopy (MFM) for the magnetic dots coincide with the magnetic configurations of 20-50 Oe computed using the Landau-Lifshitz-Gilbert (LLG) equation.","Domain structure; Magnetic annular dot; Magnetic configuration; Magnetic memory; Magnetic state","Magnetic circuits; Magnetic domains; Microscopic examination; Annular dots; Magnetization","","","","","","","Tehrani S., Slaughter J.M., Chen E., Durlam M., Shi J., Deherrera M., IEEE Trans. Magn., 35, (1999); Zhu J., Zheng Y., Prinz G.A., J. Appl. Phys., 87, (2000); Rothman J., Klaui M., Lopez-Diaz L., Vaz C.A.F., Bleloch A., Bland J.A.C., Cui Z., Speaks S., Phys. Rev. Lett., 86, (2001); Nakatani R., Hoshino K., Noguchi S., Sugita Y., Jpn. J. Appl. Phys., 33, (1994); Shinjo T., Okuno T., Hassdorf R., Shigeto K., Ono T., Science, 289, (2000); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Tricker D.M., Phys. Rev. Lett., 83, (1999); Guslienko K.Yu., Novosad V., Otani Y., Shima H., Fukamichi K., Appl. Phys. Lett., 78, (2001); Cowburn R.P., Koltsov D.K., Adeyeye A.O., Welland M.E., Europhys. Lett., 48, (1999)","","","Japan Society of Applied Physics","","","","","","00214922","","JAPND","","English","Jpn J Appl Phys Part 1 Regul Pap Short Note Rev Pap","Article","Final","","Scopus","2-s2.0-0036994907" +"Bertotti G.; Serpico C.; Mayergoyz I.D.; Bonin R.; Magni A.; D'Aquino M.","Bertotti, G. (7005370974); Serpico, C. (23013514800); Mayergoyz, I.D. (35495971500); Bonin, R. (9736915400); Magni, A. (7007060492); D'Aquino, M. (9732823500)","7005370974; 23013514800; 35495971500; 9736915400; 7007060492; 9732823500","Magnetization self-oscillations induced by spin-polarized currents","2005","IEEE Transactions on Magnetics","41","10","","2574","2576","2","5","10.1109/TMAG.2005.854661","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-27744527353&doi=10.1109%2fTMAG.2005.854661&partnerID=40&md5=0ffabe3ffe2990a5dff05a8c557c2b2e","IEN Galileo Ferraris, INRIM, I-10135 Torino, Italy; Dipartimento di Ingegneria Elettrica, Università di Napoli Federico II, I-80125 Napoli, Italy; Department of Electrical and Computer Engineering, UMIACS, University of Maryland, College Park, MD 20742, United States; Politecnico di Torino, I-10129 Torino, Italy","Bertotti G., IEN Galileo Ferraris, INRIM, I-10135 Torino, Italy; Serpico C., Dipartimento di Ingegneria Elettrica, Università di Napoli Federico II, I-80125 Napoli, Italy; Mayergoyz I.D., Department of Electrical and Computer Engineering, UMIACS, University of Maryland, College Park, MD 20742, United States; Bonin R., IEN Galileo Ferraris, INRIM, I-10135 Torino, Italy, Politecnico di Torino, I-10129 Torino, Italy; Magni A., IEN Galileo Ferraris, INRIM, I-10135 Torino, Italy; D'Aquino M., Dipartimento di Ingegneria Elettrica, Università di Napoli Federico II, I-80125 Napoli, Italy","The effect of a spin-polarized current on magnetization dynamics is described by the Landau-Lifshitz-Gilbert (LLG) equation with the addition of Slonczewski spin-transfer term. Detailed predictions about the existence, position, and stability of magnetization self-oscillations induced by the spin-polarized current are obtained by an analytical perturbative method for different levels of current injection and externally applied field. The two cases of opposite direction of current flow are discussed. © 2005 IEEE.","Bifurcation theory; Landau-Lifshitz-Gilbert equation; Spin-torque effect","Bifurcation (mathematics); Electric currents; Perturbation techniques; Landau-Lifshitz-Gilbert (LLG) equation; Spin-torque effect; Magnetization","","","","","MIUR-FIRB, (RBAU01B2T8); U.S. Department of Energy, USDOE; Indian Statistical Institute, ISI","This work was supported by MIUR-FIRB Contract RBAU01B2T8, by ISI Lagrange Fellow Program, and by the U.S. Department of Energy.","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Berger L., Phys. Rev. B, 54, (1996); Katine J.A., Et al., Phys. Rev. Lett., 84, (2000); Kiselev S.I., Et al., Nature, 425, (2003); Rippard W.H., Et al., Phys. Rev. Lett., 92, (2004); Perko L., Differential Equations and Dynamical Systems, (1996); Bertotti G., Et al., Physica B, 343, (2004)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-27744527353" +"Serpico C.; D'Aquino M.; Bertotti G.; Mayergoyz I.D.","Serpico, C. (23013514800); D'Aquino, M. (9732823500); Bertotti, G. (7005370974); Mayergoyz, I.D. (35495971500)","23013514800; 9732823500; 7005370974; 35495971500","Analytical approach to current-driven self-oscillations in Landau-Lifshitz-Gilbert dynamics","2005","Journal of Magnetism and Magnetic Materials","290-291 PART 1","","","502","505","3","27","10.1016/j.jmmm.2004.11.512","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944347531&doi=10.1016%2fj.jmmm.2004.11.512&partnerID=40&md5=ae23a27b0f3abc3601d28355286d0673","Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; Ist. Elettrotecn. Naz. Galileo F., I-10135 Torino, Strada delle Cacce, 91, Italy; Dept. of Elec. and Comp. Engineering, University of Maryland, College Park, MD 20742, United States","Serpico C., Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; D'Aquino M., Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; Bertotti G., Ist. Elettrotecn. Naz. Galileo F., I-10135 Torino, Strada delle Cacce, 91, Italy; Mayergoyz I.D., Dept. of Elec. and Comp. Engineering, University of Maryland, College Park, MD 20742, United States","Nonlinear magnetization dynamics in uniformly magnetized bodies subject to spin-polarized current, is described by Landau-Lifshitz-Gilbert (LLG) equation with an additional spin-transfer torque term. The resulting magnetization dynamics may exhibit self-oscillatory regimes, i.e. limit cycles. By using the fact that spin-transfer torque and Gilbert damping are small perturbations of the conservative LLG dynamics, the analysis of limit cycles is carried out by an appropriate perturbation method known as Melnikov-function technique. The technique is then applied to the analysis of a typical current-driven switching process in magnetic thin film. Analytical formulas for frequency, amplitude of limit cycles in function of the injected current are derived along with critical values of current which characterized the switching process. Finally, the accuracy of the perturbative technique is tested by comparing analytical results with numerical solutions. © 2004 Published by Elsevier B.V.","Laundau-Lifshitz-Gilbert equation; Limit cycles; Magnetization dynamics; Spin-transfer torque","Current density; Damping; Integration; Magnetic storage; Magnetic thin films; Perturbation techniques; Torque; Laundau-Lifshitz-Gilbert equation; Limit cycles; Magnetization dynamics; Spin-transfer torque; Magnetization","","","","","MIUR-FIRB, (RBAU01B2T8)","This work is supported by Italian MIUR-FIRB Contract no. RBAU01B2T8.","Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Sun J.Z., J. Magn. Magn. Mater., 202, (1999); Kiselev S.I., Et al., Nature, 425, (2003); Grollier J., Phys. Rev. B, 67, (2003); Bertotti G., Mayergoyz I.D., Serpico C., Physica B, 343, (2004); Perko L., Differential Equations and Dynamical Systems, (1996)","Department of Electrical Engineering, University of Napoli Federico II, I-80125, via Claudio 21, Italy; email: serpico@unina.it","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-14944347531" +"Braselton J.P.; Abell M.L.; Braselton L.M.","Braselton, James P. (6603958372); Abell, Martha L. (7005343030); Braselton, Lorraine M. (6505959740)","6603958372; 7005343030; 6505959740","Generalized Walker solutions to the Landau-Lifshitz-Gilbert equations","2001","International Journal of Non-Linear Mechanics","36","4","","571","579","8","5","10.1016/S0020-7462(00)00034-2","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0035372793&doi=10.1016%2fS0020-7462%2800%2900034-2&partnerID=40&md5=03b0cfaed617532762917ff54f99d223","Dept. of Math. and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P.O. Box 8093, United States","Braselton J.P., Dept. of Math. and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P.O. Box 8093, United States; Abell M.L., Dept. of Math. and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P.O. Box 8093, United States; Braselton L.M., Dept. of Math. and Computer Science, Georgia Southern University, Statesboro, GA 30460-8093, P.O. Box 8093, United States","By assuming that φ = φ0 is fixed, exact solutions to the LLG equations can be found. Graphs of M indicate that the vectors align as expected of the behavior of ferromagnets. Graphs of θ(x,t) and w(x,t) are useful in visualizing that energy peaks occur along the boundary of the region where the magnetization is constant.","","Computational complexity; Differential equations; Dynamics; Theorem proving; Vectors; Landau-Lifshitz-Gilbert equations; Walker solutions; Ferromagnetic materials","","","","","","","Broz J.S., Braun H.B., Brodbeck O., Baltensperger W., Helman J.S., Nucleation of magnetization reversal via creation of pairs of Bloch walls, Phys. Rev. Lett., 65, pp. 787-789, (1990); Dillon J.F., Domains and Domain Walls, Magnetism, 3, (1963); Helman J.S., Braun H.B., Broz J.S., Baltensperger W., General solution of the Landau-Lifshitz-Gilbert equations linearized around a Bloch wall, Phys. Rev. B, 43, pp. 5908-5914, (1991); Schryer N.L., Walker L.R., The motion of 180° domian walls in uniform dc magnetic fields, J. Appl. Phys., 45, pp. 5406-5421, (1974)","","","Elsevier Science Ltd","","","","","","00207462","","IJNMA","","English","Int J Non Linear Mech","Article","Final","","Scopus","2-s2.0-0035372793" +"Giuffrida C.; Ragusa C.; Repetto M.","Giuffrida, Cinzia (8313824400); Ragusa, Carlo (6603386642); Repetto, Maurizio (7102465243)","8313824400; 6603386642; 7102465243","Magnetization dynamics in metallic thin films by finite formulation","2005","Journal of Magnetism and Magnetic Materials","290-291 PART 1","","","475","478","3","0","10.1016/j.jmmm.2004.11.578","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-14944353456&doi=10.1016%2fj.jmmm.2004.11.578&partnerID=40&md5=8db06d6d5c7882153bd8a6a487cb6589","Politecnico Di Torino, I-10129, Torino, Corso Duca degli Abruzzi 24, Italy","Giuffrida C., Politecnico Di Torino, I-10129, Torino, Corso Duca degli Abruzzi 24, Italy; Ragusa C., Politecnico Di Torino, I-10129, Torino, Corso Duca degli Abruzzi 24, Italy; Repetto M., Politecnico Di Torino, I-10129, Torino, Corso Duca degli Abruzzi 24, Italy","We propose a method for the numerical solution of micromagnetic equation in a metallic thin film, including eddy currents and exchange fields, where all spatial components of magnetizations and effective fields are considered as a function of the film depth. This problem requires the solution of Landau-Lifshitz-Gilbert equation, governing magnetization dynamics, coupled to Maxwell equations for electromagnetic fields: for this purpose finite formulation of electromagnetic field has been used. Magnetization dynamics regarding different applied field patterns are discussed. © 2004 Elsevier B.V. All rights reserved.","Eddy current; Micromagnetic calculation; Numerical simulation; Thin films","Computer simulation; Eddy currents; Electromagnetic field effects; Integration; Magnetization; Maxwell equations; Thin films; Finite formulation of electromagnetic fields (FFEF); Landau-Lifshitz-Gilbert (LLG) equation; Magnetization dynamics; Micromagnetic calculation; Metallic films","","","","","","","Brown W.F., Micromagnetics, (1963); Tonti E., IEEE Trans. Magn., 38, (2002); Bertotti G., Serpico C., Mayergoyz I., Phys. Rev. Lett., 86, (2001); Magni A., Et al., Physica B, 306, (2001); Bertotti G., Et al., J. Appl. Phys., 91, (2002)","C. Giuffrida; Politecnico Di Torino, I-10129, Torino, Corso Duca degli Abruzzi 24, Italy; email: cinzia.giuffrida@polito.it","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-14944353456" +"Miyashita E.; Taguchi R.; Funabashi N.; Tamaki T.; Okuda H.","Miyashita, Eiichi (7004694330); Taguchi, Ryo (36948685100); Funabashi, Nobuhiko (7003826900); Tamaki, Takahiko (7202609924); Okuda, Haruo (7202093306)","7004694330; 36948685100; 7003826900; 7202609924; 7202093306","Effects of the exchange stiffness constant and the distribution on the recording characteristics of perpendicular media","2002","Digests of the Intermag Conference","","","","EQ04","","","1","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0036914030&partnerID=40&md5=27521b77588f30a35ca5daade8a662b6","NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan","Miyashita E., NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan; Taguchi R., NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan; Funabashi N., NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan; Tamaki T., NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan; Okuda H., NHK Sci. and Tech. Research Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan","The effects of the exchange stiffness constant and the distribution on the recording characteristics of perpendicular media were discussed. A micromagnetic simulation based on the LLG equation was performed. Signal and noise increased with higher Aex but the signal to noise ratio (SNR) of the media was maximum at Aex = 0.05 [× 10-6 erg/cm]. The relationship of the cluster size and the exchange stiffness in the AC erased state was also investigated.","","Computer simulation; Magnetic domains; Magnetic materials; Magnetization; Signal to noise ratio; Exchage stiffness constant; Magnetic recording","","","","","","","","E. Miyashita; NHK Sci. and Technical Res. Labs., Tokyo 157-8510, 1-10-11 Kinuta, Setagaya-ku, Japan; email: miyasita@strl.nhk.or.jp","","","IEEE","2002 IEEE International Magnetics Conference-2002 IEEE INTERMAG","28 April 2002 through 2 May 2002","Amsterdam","60350","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-0036914030" +"Guo J.; Jalil M.B.A.","Guo, Jie (55709457700); Jalil, Mansoor Bin Abdul (7006821429)","55709457700; 7006821429","Combined ballistic and diffusive model of spin-polarized current-induced magnetization switching in pseudo-spin-valve structure","2005","Physical Review B - Condensed Matter and Materials Physics","71","22","224408","","","","18","10.1103/PhysRevB.71.224408","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-28344442967&doi=10.1103%2fPhysRevB.71.224408&partnerID=40&md5=a5fa003269084a9885edbd045dfb2fdb","Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore","Guo J., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore; Jalil M.B.A., Information Storage Materials Laboratory, Electrical and Computer Engineering Department, National University of Singapore, Singapore 117576, 4 Engineering Drive 3, Singapore","We present a theoretical model of spin transport and spin transfer in a Co Cu Co pseudo-spin-valve (PSV) structure, which combines ballistic spin injection across the interfaces of the PSV, and diffusive spin relaxation within the free Co layer. The ballistic spin injection model considers spin-differential transmission and reflection probabilities at the two Co-Cu interfaces, and the effect of multiple reflections at the interfaces. This ballistic process causes the incident spin current at the spacer-free Co interface to undergo spin rotation and to be reduced to a fraction of the spin current in the pinned Co layer. There are two contributions to the spin transfer to the free Co layer, i.e., (a) the fraction of the incident spin current which is ""absorbed"" at the interface in order to conserve spin momentum at the interface (neglected in previous purely diffusive models) and (b) spin relaxation of the transverse spin accumulation, due to a combination of spin scattering and precession. The magnitudes of these two components are calculated based on typical experimental parameters, and the switching fields due to spin torques in the in-plane and out-of-plane directions are derived by considering a modified Landau-Lifshitz-Gilbert (LLG) equation. Based on known values of switching magnetic fields of Co Cu Co PSV, the calculated critical current density ranges from 2.5to 8.2×107Acm-2, in agreement with observed values in current-induced magnetization switching experiments. © 2005 The American Physical Society.","","","","","","","","","Berger L., Phys. Rev. B, 54, (1996); Slonczewski J.C., J. Magn. Magn. Mater., 159, (1996); Tsoi M., Jansen A.G.M., Bass J., Chiang W.-C., Seck M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, (1998); Kelly D., Wegrowe J.-E., Truong T.-K., Hoffer X., Guittienne P., Ansermet J.-P., Phys. Rev. B, 68, (2003); Katine J.A., Albert F.J., Buhrman R.A., Myers E.B., Ralph D.C., Phys. Rev. Lett., 84, (2000); Albert F.J., Emley N.C., Myers E.B., Ralph D.C., Buhrman R.A., Phys. Rev. Lett., 89, (2002); Oezyilmaz B., Kent A.D., Monsma D., Sun J.Z., Rooks M.J., Koch R.H., Phys. Rev. Lett., 91, (2003); Fuchs G.D., Emley N.C., Krivorotov I.N., Braganca P.M., Ryan E.M., Kiselev S.I., Sankey J.C., Ralph D.C., Buhrman R.A., Katine J.A., Appl. Phys. Lett., 85, (2004); Slonczewski J.C., J. Magn. Magn. Mater., 195, (1999); Stiles M.D., Zangwill A., J. Appl. Phys., 91, (2002); Heide C., Zilberman P.E., Elliott R.J., Phys. Rev. B, 63, (2001); Zhang S., Levy P.M., Fert A., Phys. Rev. Lett., 88, (2002); Shpiro A., Levy P.M., Zhang S., Phys. Rev. B, 67, (2003); Stiles M.D., J. Appl. Phys., 79, (1996); Castano F.J., Hao Y., Hwang M., Ross C.A., Vogeli B., Smith H.I., Haratani S., Appl. Phys. Lett., 79, (2001); Albert F.J., Katine J.A., Buhrman R.A., Ralph D.C., Appl. Phys. Lett., 77, (2000)","","","","","","","","","1550235X","","PRBMD","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","","Scopus","2-s2.0-28344442967" +"Humphrey F.B.; Redjdal M.","Humphrey, F.B. (7006179177); Redjdal, M. (6603923518)","7006179177; 6603923518","Domain wall structure in bulk magnetic materials","1994","Journal of Magnetism and Magnetic Materials","133","1-3","","11","15","4","8","10.1016/0304-8853(94)90476-6","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0028424750&doi=10.1016%2f0304-8853%2894%2990476-6&partnerID=40&md5=abbbbfdb4d887aa255e095b530718b47","Boston University, Dept. of ECS Engineering, Boston, MA 02215, 44 Cummington St, United States","Humphrey F.B., Boston University, Dept. of ECS Engineering, Boston, MA 02215, 44 Cummington St, United States; Redjdal M., Boston University, Dept. of ECS Engineering, Boston, MA 02215, 44 Cummington St, United States","A cross section of a wall in 10 μm thick material with Permalloy characteristics has been simulated on the massively parallel Thinking Machine system CM2 using direct integration of the LLG equation. A Cartesian lattice of 256 nodes representing 20 μm normal to the wall and 128 nodes in thickness was used. The expected stray-field-free structure was found with a vortex that extends nearly 10 μm from the Bloch wall center. The Bloch wall itself was well formed over 80% of the thickness with two thin Néel-like surface walls of opposite chirality. The Néel caps were wide and very asymmetric. If a width definition of 10%-10% of the wall normal magnetization is used, the width is 8.3 μm. The vortex is large and only on one side of the wall extending 10 μm to the edge of the simulation with as much as 10° tilt of the magnetization away from the easy axis. The width of the Bloch wall in the sample center was 15% smaller than that predicted by the classic wall width. © 1994.","","Artificial intelligence; Computer simulation; Integration; Magnetic fields; Magnetic materials; Magnetization; Mathematical models; Parallel processing systems; Bloch wall; Cartesian lattice; Domain wall structure; Landau Lifshitz Gilbert equation; Magnetic vortex; Neel-like surface wall; Permalloy; Stray field free surface; Thinking Machine system CM2; Magnetic domains","","","","","Ballistic Missile DefenseO rgani-zation/InnovativSec iencea nd TechnologyO ffice; Center for Space MicroelectronicTse chnology; Office of AdvancedC onceptsa nd Technology; National Aeronautics and Space Administration, NASA","Acknowledgement. The research describedi n this paperw as performed(i n part) for the Center for Space MicroelectronicTse chnology,Je t Propulsion Laboratory, CaliforniaI nstituteo f Technologya, nd was sponsored (in part) by the Ballistic Missile DefenseO rgani-zation/InnovativSec iencea nd TechnologyO ffice, and the National Aeronauticsa nd Space Administration, Office of AdvancedC onceptsa nd Technology.","Kittel, Rev. Mod. Phys., 21, (1949); Scheinfein, Unguris, Blue, Coakley, Price, Celotta, Ryan, Phys. Rev. B, 43, (1991); Scheinfein, Unguris, Price, Celotta, J. Appl. Phys., 67, (1990); Shir, J. Appl. Phys., 49, (1978); Patterson, Giles, Humphrey, J. Appl. Phys., 69, (1991); Bagneres, Humphrey, IEEE Trans. Magn., 28, (1992); LaBonte, J. Appl. Phys., 40, (1969); Yuan, Bertram, J. Appl. Phys., 73, (1993); Giles, Kotiuga, Humphrey, J. Appl. Phys., 67, (1990); Scheinfein, Unguris, Celotta, Price, Phys. Rev. Lett., 63, (1989); Schafer, Ho, Yamasaki, Hubert, Humphrey, IEEE Trans. Magn., 27, (1991); Hockney, Meth. Comput. Phys., 9, (1970); Eastwood, Brownrigg, J. Comput. Phys., 32, (1979); Hubert, Theorie der Domänenwäde in geordneten Medien, (1974); Aharoni, Jakubovics, Phys. Rev. B, 43, (1991)","F.B. Humphrey; Boston University, Dept. of ECS Engineering, Boston, MA 02215, 44 Cummington St, United States; email: FBH@BUENGA.BU.EDU","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","All Open Access; Hybrid Gold Open Access","Scopus","2-s2.0-0028424750" +"Yilgin R.; Oogane M.; Yakata S.; Ando Y.; Miyazaki T.","Yilgin, Resul (9244881300); Oogane, Mikihiko (9733080100); Yakata, Stoshi (13612865000); Ando, Yasuo (7401803498); Miyazaki, Terunobu (8547213500)","9244881300; 9733080100; 13612865000; 7401803498; 8547213500","Intrinsic Gilbert damping constant in Co2MnAl Heusler alloy films","2005","IEEE Transactions on Magnetics","41","10","","2799","2801","2","35","10.1109/TMAG.2005.854832","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-27744601673&doi=10.1109%2fTMAG.2005.854832&partnerID=40&md5=047fcaa452e2fa0fd9809cef593cd2db","Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan","Yilgin R., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Oogane M., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Yakata S., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Ando Y., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan; Miyazaki T., Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan","Intrinsic α-damping constants of Co2MnAl Heusler alloy films prepared by magnetron sputtering were investigated. After deposition of Co2MnAl films, the films were annealed at 200-400°C to control the crystal structure and the atomic order between Co, Mn, and Al sites. Ferromagnetic resonance (FMR) technique was used to obtain α values of Co2MnAl films in this study. Out-of-plane angular dependences of the resonance field (HR) and line width (ΔHpp) of FMR spectra were measured and fitted using the Landau-Lifshitz-Gilbert (LLG) equation. The authors were able to fit all experimental results well because of the lack of inhomogeneities in prepared Co2MnAl films. The α-damping constants obtained from the fitting results decreased with increasing annealing temperature and showed a minimum value of 0.007 at 300°C. It was found that a degree of B2 structure order can sensitively affect α-damping constants of Co2MnAl films. © 2005 IEEE.","Ferromagnetic resonance (FMR); Heusler alloy; Linewidth; Resonance field; α-Gilbert damping constant","Annealing; Crystal structure; Damping; Deposition; Ferrimagnetic resonance; Magnetron sputtering; Thermal effects; Thin films; Heusler alloy; Linewidth; Resonance fields; α-Gilbert damping constant; Cobalt alloys","","","","","Universal Low-Power Spin Memory; Ministry of Education, Culture, Sports, Science and Technology, MEXT; New Energy and Industrial Technology Development Organization, NEDO","This work was supported by the IT-program of Research Revolution 2002 (RR2002) “Development of Universal Low-Power Spin Memory,” Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan, and the NEDO Grant Program.","Webster P.J., J. Phys. Chem. Solids, 32, pp. 1221-1231, (1971); Pickett W.E., Moodera J.S., Half metallic magnets, Phys. Today, 54, 5, pp. 39-44, (2001); Mizukami S., Ando Y., Miyazaki T., The study on ferromagnetic resonance linewidth for NM/80NiFe/NM (NM = Cu, Ta, Pd and Pt) films, Jpn. J. Appl. Phys., 40, 2 A, pp. 580-585, (2001); Miura Y., Nagao K., Shirai M., Atomic disorder effects on half-metallicity of the full-Heusler alloys Co2(Cr1-xFex)Al: A first-principles study, Phy. Rev. B, 69, (2004); Gilbert T.L., A Lagrangian formulation of gyromagnetic equation of the magnetization field, Phys. Rev., 100, (1955); Chikazumi S., Phys. Magn., (1964); Mizukami S., Ando Y., Miyazaki T., Phys. Rev. B, 66, (2002); Heinrich B., Fraitova D., Kambersky V., Phys. Stat. Solid., 23, (1967); Kambersky V., On the Landau-Lifshitz relaxation in ferromagnetic metals, Can. J. Phys., 48, pp. 2906-2911, (1970)","","","Institute of Electrical and Electronics Engineers Inc.","","","","","","00189464","","IEMGA","","English","IEEE Trans Magn","Article","Final","","Scopus","2-s2.0-27744601673" +"Mitsumata C.; Shimoe O.","Mitsumata, C. (6603204999); Shimoe, O. (23032224000)","6603204999; 23032224000","Instability analysis of SAL-biased magnetoresistive heads using rotational applied field","1997","Journal of Applied Physics","81","8 PART 2B","","4884","4886","2","0","10.1063/1.364866","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-6144238272&doi=10.1063%2f1.364866&partnerID=40&md5=554df797261e104f208cf616d5df084a","Magnetic Electron. Mat. Res. Lab., Hitachi Metals, Limited, Moka, Tochigi 321-43, Japan","Mitsumata C., Magnetic Electron. Mat. Res. Lab., Hitachi Metals, Limited, Moka, Tochigi 321-43, Japan; Shimoe O., Magnetic Electron. Mat. Res. Lab., Hitachi Metals, Limited, Moka, Tochigi 321-43, Japan","Magnetoresistive (MR) head achieves high areal density in a magnetic recording system due to high sensitivity of the magnetic field. The high sensitivity of MR sensor, however, potentially causes an instability of readback signals. This instability appears as a variation of the output wave form during alternating reading and writing processes. In this study, MR heads were measured by a new technique that used rotational applied field. This technique is intended for checking the stability of magnetic domains against the arbitrary direction of the magnetic field. As a result, deviations of transfer curves for the MR sensor correlated to variations of the output voltage. This deviation seems to be caused by the Barkhausen jump in MR sensors. In order to analyze the Barkhausen jump, a simulation using the Landau-Lifshitz-Gilbert (LLG) equation was carried out. A calculated transfer curve of the MR sensor was similar to a measured curve, and it included two different origins of the Barkhausen jump. The first type of jump happened in the MR film. A rotational applied field generated domain walls in the active region of the MR film. The second type of jump occurred in the soft adjacent layer (SAL) film. The appearance of vortex domain walls, changed the bias field from the SAL film, and then it forced a bias state variation in the MR film. The first type and second type of Barkhausen jump showed 0.05 and 0.01 Ω resistance change, respectively. But, in reducing the MR sensor height, the Barkhausen jump was suppressed, even in the case of a small domain stabilizing bias field. © 1997 American Institute of Physics.","","","","","","","","","Yuan S.W., Et al., IEEE Trans. Magn., MAG-31, (1995); Yuan S.W., Bertram H.N., IEEE Trans. Magn., MAG-29, (1993); Mitsumata C., Et al., IEEE Trans. Magn., MAG-31, (1995); Zhu J.-G., O'Connor D.J., IEEE Trans. Magn., MAG-32, (1996)","","","American Institute of Physics Inc.","","","","","","00218979","","JAPIA","","English","J Appl Phys","Article","Final","","Scopus","2-s2.0-6144238272" +"Hrkac G.; Kirschner M.; Dorfbauer F.; Suess D.; Ertl O.; Fidler J.; Schrefl T.","Hrkac, G. (9732912400); Kirschner, M. (9733642800); Dorfbauer, F. (8212208900); Suess, D. (7004076065); Ertl, O. (9732451000); Fidler, J. (35601590600); Schrefl, T. (7005780657)","9732912400; 9733642800; 8212208900; 7004076065; 9732451000; 35601590600; 7005780657","Three-dimensional micromagnetic finite element simulations including eddy currents","2005","Journal of Applied Physics","97","10","10E311","","","","30","10.1063/1.1852211","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944436228&doi=10.1063%2f1.1852211&partnerID=40&md5=c5b42667b28ae018abd8750ed66dca54","Vienna University of Technology, Vienna, 1040, Austria; Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Sheffield S1 3JD, Mappin Street, United Kingdom","Hrkac G., Vienna University of Technology, Vienna, 1040, Austria; Kirschner M., Vienna University of Technology, Vienna, 1040, Austria; Dorfbauer F., Vienna University of Technology, Vienna, 1040, Austria; Suess D., Vienna University of Technology, Vienna, 1040, Austria; Ertl O., Vienna University of Technology, Vienna, 1040, Austria; Fidler J., Vienna University of Technology, Vienna, 1040, Austria; Schrefl T., Department of Engineering Materials, University of Sheffield, Sir Robert Hadfield Building, Sheffield S1 3JD, Mappin Street, United Kingdom","We developed a micromagnetic eddy current method that allows arbitrary geometries, requires no mesh outside the ferromagnet, and uses a stable integration scheme. We simultaneously solve the Landau-Lifshitz-Gilbert equation and the quasistatic Maxwell equations using a hybrid finite element/boundary element method (FEM/BEM). The eddy current field is directly calculated from the space time behavior of the magnetization rate of change. The boundary conditions of the eddy current field at infinity are taken into account using a FEM/BEM scheme. The resulting system of differential algebraic equations is solved using a backward differentiation method. © 2005 American Institute of Physics.","","Approximation theory; Boundary conditions; Boundary element method; Computer simulation; Damping; Differential equations; Eddy currents; Ferromagnetic materials; Finite element method; Integration; Magnetization; Maxwell equations; Damping constant; Landau-Lifshitz-Gilbert (LLG) equations; Magnetization rate; Quasistatic approximation; Magnetism","","","","","Austrian Science Fund, FWF"," This project was supported by the Austrian Science Fund (Grant No. Y132-N02). ","Della Torre E., Eicke J., IEEE Trans. Magn., 33, (1997); Sandler G.M., Bertram H.N., J. Appl. Phys., 81, (1997); Kalimov A., Vaznov S., Voronina T., IEEE Trans. Magn., 33, (1997); Serpico C., Mayergoyz I.D., Bertotti G., IEEE Trans. Magn., 37, (2001); Bertotti G., Hysteresis in Magnetism, pp. 91-102, (1998); Koehler T.R., Physica B, 233, (1997); Brown P.N., Hindmarsh A.C., Petzold L.R., SIAM J. Sci. Comput. (USA), 19, (1998); Brown P.N., Hindmarsh A.C., Petzold L.R., SIAM J. Sci. Comput. (USA), 15, (1994); Torres L., Lopez-Diaz L., Martinez E., Alejos O., Physica B, 343, (2004)","G. Hrkac; Vienna University of Technology, Vienna, 1040, Austria; email: hrkac@magnet.atp.tuwien.ac.at","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","","Scopus","2-s2.0-20944436228" +"Gibbons M.R.","Gibbons, Matthew R. (22947187200)","22947187200","Micromagnetic simulation using the dynamic alternating direction implicit method","1998","Journal of Magnetism and Magnetic Materials","186","3","","389","401","12","26","10.1016/S0304-8853(98)00105-X","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-0032474662&doi=10.1016%2fS0304-8853%2898%2900105-X&partnerID=40&md5=7cc26c02758f881a663348c98b22ee31","Lawrence Livermore Natl. Laboratory, Livermore, CA 94550, 7000 East Ave., L-395, United States","Gibbons M.R., Lawrence Livermore Natl. Laboratory, Livermore, CA 94550, 7000 East Ave., L-395, United States","We have developed a 3-D micromagnetic algorithm using finite-differences and the iterative matrix solution method, dynamic alternating direction implicit (DADI), for the magnetostatic potential equation. As in previous work, the magnetization is integrated in time toward equilibrium with the Landau-Lifshitz-Gilbert (LLG) equation. We have found that only one iteration of DADI is needed for each time step of the LLG equation. The resulting algorithm has relatively short computation times even for simulations with linearly permeable structures of various shapes. In addition to the magnetostatic field the effective H-field includes exchange coupling, crystalline anisotropy, interlayer exchange coupling, and current-induced fields allowing the simulation of a wide range of devices. © 1998 Elsevier Science B.V. All rights reserved.","Magnetoresistive head simulation; Micromagnetic simulation; Spin-valves","Algorithms; Computational complexity; Computer simulation; Finite difference method; Integration; Iterative methods; Magnetic anisotropy; Magnetization; Magnetoresistance; Matrix algebra; Dynamic alternating direction implicit (DADI) method; Landau-Lifshitz-Gilbert (LLG) equation; Micromagnetic simulation; Magnetostatics","","","","","U.S. Department of Energy, USDOE; Lawrence Livermore National Laboratory, LLNL, (W-7405-ENG-48)","The author thanks D. Hewett, C. Cerjan, and R. Spencer for assistance in beginning this work and useful discussions. This work was performed under the auspices of the United States Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-ENG-48.","Brown W.F., Micromagnetics, (1963); Aharoni A., Introduction to the Theory of Ferromagnetism, (1996); Koehler T.R., Fredkin D.R., IEEE Trans. Magn., 28, 2, (1992); Berkov D.V., Ramstock K., Hubert A., Phys. Stat. Sol. (A), 137, (1993); Labonte A.E., J. Appl. Phys., 40, 6, (1969); Scheinfein M.R., Blue J.L., J. Appl. Phys., 69, 11, (1991); Yuan S.W., Bertram H.N., Phys. Rev. B, 44, 22, (1991); Fredkin D.R., Koehler T.R., IEEE Trans. Magn., 26, 2, (1990); Koehler T.R., IEEE Trans. Magn., 30, 6, (1994); Yuan S.W., Bertram H.N., Bhattacharyya N.K., IEEE Trans. Magn., 30, 2, (1994); Bhattacharyya M.K., Gill H.S., Hesterman V.W., Compumag Digest, (1989); Doss S., Miller K., SIAM J. Numer. Anal., 16, (1979); Kittel C., Gait J.K., Solid State Phys., 3, (1956); Baibich M.N., Broto J.M., Fert A., Van Nguyen Dau F., Petroff F., Etienne P., Creuzet B., Frederick A., Chazelas J., Phys. Rev. Lett., 61, (1988); Binash G., Grunberg P., Saurenback F., Zinn W., Phys. Rev. B, 39, (1989); Hathaway K.B., Ultrathin Magnetic Structures II, (1994); Hewett D.W., Larson D.J., Doss S., J. Comput. Phys., 101, (1992); Douglas J., Numer. Math., 4, (1962); Nakatani Y., Uesaka Y., Hayashi N., Jpn. J. Appl. Phys., 28, (1989); Birdsall C.K., Langdon A.B., Plasma Physics Via Computer Simulation, (1985); Scheinfein M.R., Et al., Phys. Rev. B, 43, 4, (1991); Aharoni A., J. Appl. Phys., 39, 2, (1968); Anthony T.C., Brug J.A., Zhang S., IEEE Trans. Magn., 30, (1994); Dieny B., Speriosu V.S., Parkin S.S.P., Gurney B.A., Wilhoit D.R., Mauri D., Phys. Rev. B, 43, (1991); Heim D.E., Fontana R.E. Jr., Tsang C., Speriosu V.S., Gurney B.A., Williams M.L., IEEE Trans. Magn., 30, (1994); Yuan S.W., Bertram H.N., J. Appl. Phys., 75, 10, (1994); Jones R.E., Mee C.D., Tsang C., Recording Heads, Magnetic Recording Technology, (1996); Kanai H., Et al., IEEE Trans. Magn., 31, (1995); Fredkin D.R., Koehler T.R., J. Appl. Phys., 67, 9, (1990); Kools J.C.S., IEEE Trans. Magn., 32, 4, (1996); Hewett D.W., J. Comput. Phys., (1997)","","","Elsevier","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Article","Final","","Scopus","2-s2.0-0032474662" +"Asada H.; Ii H.; Yamasaki J.; Takezawa M.; Koyanagi T.","Asada, H. (7203075175); Ii, H. (57062423600); Yamasaki, J. (7006278022); Takezawa, M. (7005864857); Koyanagi, T. (7201472432)","7203075175; 57062423600; 7006278022; 7005864857; 7201472432","Micromagnetic study of domain-wall pinning characteristics with grooves in thin films","2005","Journal of Applied Physics","97","10","10E317","","","","4","10.1063/1.1857652","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-20944443150&doi=10.1063%2f1.1857652&partnerID=40&md5=99626f9ead049b7c024124ca88fbe92f","Department of Symbiotic Environmental System Engineering, Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, 2-16-1 Tokiwadai, Japan; Department of Applied Science for Integrated System Engineering, Graduate School of Engineering, Kyushu Institute of Technology, Tobata-ku, Kitakyushu 804-8550, 1-1 Sensui-cho, Japan","Asada H., Department of Symbiotic Environmental System Engineering, Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, 2-16-1 Tokiwadai, Japan; Ii H., Department of Symbiotic Environmental System Engineering, Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, 2-16-1 Tokiwadai, Japan; Yamasaki J., Department of Applied Science for Integrated System Engineering, Graduate School of Engineering, Kyushu Institute of Technology, Tobata-ku, Kitakyushu 804-8550, 1-1 Sensui-cho, Japan; Takezawa M., Department of Applied Science for Integrated System Engineering, Graduate School of Engineering, Kyushu Institute of Technology, Tobata-ku, Kitakyushu 804-8550, 1-1 Sensui-cho, Japan; Koyanagi T., Department of Symbiotic Environmental System Engineering, Graduate School of Science and Engineering, Yamaguchi University, Ube 755-8611, 2-16-1 Tokiwadai, Japan","The pinning characteristics of a 180° domain wall with grooves are investigated using the micromagnetic simulation. The depinning fields required to pull the wall out of the grooved region were strongly related to the pinning characteristics at each step edge. The depinning field difference between the wall movement directions was improved by the increase of the lower depinning field compared to that with the steplike thickness change. It was also found that the depinning fields for various groove widths were almost constant and the wall displacement was further suppressed by the narrower groove having the vertical edge. © 2005 American Institute of Physics.","","Boundary conditions; Computer simulation; Magnetic anisotropy; Magnetic domains; Magnetic field effects; Magnetism; Sensors; Domain-wall pinning; Film thickness; Landau-Lifshitz-Gilbert (LLG) equations; Micromagnetic simulation; Thin films","","","","","","","Klein D., Engemann J., J. Magn. Magn. Mater., 45, (1984); Suzuki T., Et al., IEEE Trans. Magn., 22, (1986); Ise K., Nakamura Y., J. Magn. Soc. Jpn., 15, (1991); Asada H., Hyodo Y., Yamasaki J., Takezawa M., Koyanagi T., IEEE Trans. Magn., 40, (2004); Konishi S., Matsuyama K., Yoshimatsu N., Sakai K., IEEE Trans. Magn., 24, (1988); Ronan G., Matsuyama K., Fujita E., Ohbo M., Kubota S., Konishi S., IEEE Trans. Magn., 21, (1985); Asada H., Matsuyama K., Gamachi M., Taniguchi K., J. Appl. Phys., 75, (1994)","","","","","","","","","00218979","","JAPIA","","English","J Appl Phys","Conference paper","Final","All Open Access; Green Open Access","Scopus","2-s2.0-20944443150" +"Nawate M.; Honda S.; Tanaka H.","Nawate, Masahiko (7003418386); Honda, Shigeo (7402362231); Tanaka, Hiroshi (55866798300)","7003418386; 7402362231; 55866798300","Domain wall confinement with thin film edges","2005","Journal of Magnetism and Magnetic Materials","287","SPEC. ISS.","","392","396","4","0","10.1016/j.jmmm.2004.10.065","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-12344304165&doi=10.1016%2fj.jmmm.2004.10.065&partnerID=40&md5=07f07a873865582366354de8d3310e35","Dept. Electronics and Contr. Syst., Shimane University, Matsue 690-8504, Nishikawatsu 1060, Japan","Nawate M., Dept. Electronics and Contr. Syst., Shimane University, Matsue 690-8504, Nishikawatsu 1060, Japan; Honda S., Dept. Electronics and Contr. Syst., Shimane University, Matsue 690-8504, Nishikawatsu 1060, Japan; Tanaka H., Dept. Electronics and Contr. Syst., Shimane University, Matsue 690-8504, Nishikawatsu 1060, Japan","Magnetization distribution has been calculated for nanocontacts consisting of two films contacted at their edges by means of a micromagnetic framework using the Laudau-Lifshitz-Gilbert formula. Two types of junctions, crossing edges (X-type) and overlapped corner (C-type) of films, are considered. In the X-type configuration, the domain wall between two films having head-to-head or tail-to-tail magnetization direction is confined when the film thickness is lowered to 4 nm. If the small-size bridge is introduced to the junction area, the wall confinement is slightly enhanced. On the other hand, for the C-type junction the domain wall width decreases with increasing film thickness. These configurations can be potential candidates for the ballistic magnetoresistance sensor which can be manufactured using thin films. © 2004 Elsevier B.V. All rights reserved.","Domain wall confinement; Film edge; LLG equation; Micromagnetics; Nanocontact","Electric conductance; Electrodeposition; Electron scattering; Magnetic domains; Magnetic heads; Magnetic recording; Magnetization; Magnetoresistance; Domain wall confinement; Film edge; LLG equation; Micromagnetics; Nanocontacts; Magnetic thin films","","","","","Shimane Industrial Promotion Foundation; Inamori Foundation","The authors are grateful to T. Hosokawa for calculations with OOMMF. They also thank Dr. M. Donahue of NIST for useful advices to construct calculation models. This work was supported by grants from The Inamori Foundation and Shimane Industrial Promotion Foundation. ","Garcia N., Munoz M., Zhao Y.-W., Phys. Rev. Lett., 82, (1999); Chopra H.D., Hua S.Z., Phys. Rev. B, 66, (2002); Tatara G., Zhao Y.-W., Munoz M., Garcia N., Phys. Rev. Lett., 83, (1999); Tatara G., J. Phys. Soc. Japan, 69, (2000); Landauer R., IBM J. Res. & Dev., 1, (1957); Nawate M., Shinohara K., Honda S., Tanaka H., Trans. Mat. Res. Soc. Jpn; Bruno P., Phys. Rev. Lett., 83, (1999)","M. Nawate; Dept. Electronics and Contr. Syst., Shimane University, Matsue 690-8504, Nishikawatsu 1060, Japan; email: nawate@ecs.shimane-u.ac.jp","","","","","","","","03048853","","JMMMD","","English","J Magn Magn Mater","Conference paper","Final","","Scopus","2-s2.0-12344304165" +"Shimatsu T.; Greaves S.J.; Muramatsu K.; Watanabe I.; Muraoka H.; Sugita Y.; Nakamura Y.","Shimatsu, T. (7006499203); Greaves, S.J. (7006831295); Muramatsu, K. (36822179200); Watanabe, I. (7402438308); Muraoka, H. (12756598400); Sugita, Y. (7202641233); Nakamura, Y. (55624471280)","7006499203; 7006831295; 36822179200; 7402438308; 12756598400; 7202641233; 55624471280","Experimental and theoretical analysis of rotational hysteresis loss in CoCrTa perpendicular recording media","2000","Digests of the Intermag Conference","","","","EB","04","","0","","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-17144437672&partnerID=40&md5=78d97e93e3aca2740193d7b033ce0541","Tohoku Univ, Sendai, Japan","Shimatsu T., Tohoku Univ, Sendai, Japan; Greaves S.J., Tohoku Univ, Sendai, Japan; Muramatsu K., Tohoku Univ, Sendai, Japan; Watanabe I., Tohoku Univ, Sendai, Japan; Muraoka H., Tohoku Univ, Sendai, Japan; Sugita Y., Tohoku Univ, Sendai, Japan; Nakamura Y., Tohoku Univ, Sendai, Japan","The value of rotational hysteresis loss (Wr) was measured for various CoCrTa perpendicular media. It was shown that Wr and the hysteresis integral Rh are dependent on the perpendicular anisotropy and the strength of intergranular exchange coupling. Simulated result using a model based on the Landau-Lifshitz-Gilbert (LLG) equation were compared with the experimental results.","","Computer simulation; Magnetic field effects; Magnetic heads; Magnetic hysteresis; Magnetic recording; Magnetic variables measurement; Magnetization; Mathematical models; Numerical methods; X ray diffraction analysis; Cobalt chromium tantalum alloys; Hysteresis loss; Intergranular exchange; Structural properties; Cobalt alloys","","","","","","","","","","IEEE","IEEE","2000 IEEE International Magnetics Conference-2000 IEEE INTERMAG","9 April 2000 through 13 April 2000","Toronto, Ont, Can","57511","00746843","","DICOD","","English","Dig Intermag Conf","Conference paper","Final","","Scopus","2-s2.0-17144437672" +"Khapikov A.","Khapikov, A. (6701650565)","6701650565","Classical spin as a nonlinear damped oscillator","2003","Intermag 2003 - Program of the 2003 IEEE International Magnetics Conference","","","1230858","","","","0","10.1109/INTMAG.2003.1230858","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-84949504291&doi=10.1109%2fINTMAG.2003.1230858&partnerID=40&md5=56d4e3fb9a2eadd064e7671c88b93723","Read-Rite Corporation, 44100 Osgood Road, Fremont, 94539, CA, United States","Khapikov A., Read-Rite Corporation, 44100 Osgood Road, Fremont, 94539, CA, United States","In this paper, the aim of our article is to describe an exact transformation of the nonlinear damped Landau-Lifshitz-Gilbert (LLG) equation written in the most general form to a system of nonlinear damped oscillators. We demonstrate that the micromagnetic and oscillatory approaches are completely equivalent. We also show how the transformed LLG equation can be applied to find the energy barrier for thermally induced magnetization reversal in two cases: an anisotropic magnetic particle in an arbitrary magnetic field and two classical anisotropic exchange-coupled spins. © 2003 IEEE.","Anisotropic magnetoresistance; Damping; Energy barrier; Magnetic fields; Magnetic particles; Magnetization; Micromagnetics; Nonlinear dynamical systems; Nonlinear equations; Oscillators","Anisotropy; Damping; Dynamical systems; Energy barriers; Enhanced magnetoresistance; Magnetic fields; Magnetism; Magnetization; Magnetization reversal; Mathematical transformations; Nonlinear dynamical systems; Oscillators (electronic); Oscillators (mechanical); Anisotropic exchange; Classical spin; Damped oscillators; Landau-Lifshitz-Gilbert equations; LLG equation; Magnetic particle; Micromagnetics; Thermally induced; Nonlinear equations","","","","","","","Safonov V.L., Bertram H.N., Phys. Rev. B, 60, (2002); Smith N., J. Appl. Phys., 92, (2002)","","","Institute of Electrical and Electronics Engineers Inc.","Magnetics Society of the Institute of Electrical and Electronics Engineers","2003 IEEE International Magnetics Conference, Intermag 2003","30 March 2003 through 3 April 2003","Boston","114081","","0780376471; 978-078037647-2","","","English","Intermag - Program IEEE Int. Magn. Conf.","Conference paper","Final","","Scopus","2-s2.0-84949504291" +"Wegrowe J.","Wegrowe, J. (7004315688)","7004315688","Thermokinetic approach of the generalized Landau-Lifshitz-Gilbert equation with spin-polarized current","2000","Physical Review B - Condensed Matter and Materials Physics","62","2","","1067","1074","7","72","10.1103/PhysRevB.62.1067","https://scopus.unalproxy.elogim.com/inward/record.uri?eid=2-s2.0-7644229909&doi=10.1103%2fPhysRevB.62.1067&partnerID=40&md5=ecfc7ee401232a867894152d7c739671","Institut de Physique Expérimentale, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland","Wegrowe J., Institut de Physique Expérimentale, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland","In order to describe the recently observed effect of current induced magnetization reversal in magnetic nanostructures, the thermokinetic theory is applied to a metallic ferromagnet in contact with a reservoir of spin-polarized conduction electrons. The spin-flip relaxation of the conduction electrons is described thermodynamically as a chemical reaction. In the two-current approximation, the diffusion equation of the chemical potential, the giant magnetoresistance at the interface and and the usual Landau-Lifshitz-Gilbert (LLG) equation is obtained from the entropy variation in the absence of current. The description of the conservation laws, including spin dependent scattering and spin injection leads to the derivation of a generalized LLG equation. The equation is applied to the measurements obtained on single magnetic Ni nanowires. © 2000 The American Physical Society.","","","","","","","","","Baibich M., Broto J., Fert A., Nguyen Van Dau F., Petroff F., Phys. Rev. Lett., 61, (1988); Binash G., Grunberg P., Saurenbach F., Zinn W., Phys. Rev. B, 39, (1989); Berger L., J. Appl. Phys., 55, (1984); Berger L., Phys. Rev. B, 54, (1996); Berger L., J. Appl. Phys., 81, (1997); Slonczewski C., J. Magn. Magn. Mater., 159, (1996); Slonczewski C., J. Magn. Magn. Mater., 195, (1999); Jones B., Phys. Rev. B, 57, (1998); Freitas P., Berger L., J. Appl. Phys., 57, (1985); Berger L., J. Appl. Phys., 63, (1988); Salhi E., Berger L., J. Appl. Phys., 76, (1994); Tsoi M., Jansen A., Bass J., Seck M., Tsoi V., Wyder P., Phys. Rev. Lett., 80, (1998); Sun J., J. Magn. Magn. Mater., 202, (1999); Myers E., Ralph D., Katine J., Louie R., Buhrman R., Science, 285, (1999); Kelly D., Jaccard Y., Europhys. Lett., 45, (1999); Gruber C., Eur. J. Phys., 20, (1999); Johnson M., Silsbee R., Phys. Rev. Lett., 55, (1985); Johnson M., Silsbee R., Phys. Rev. B, 35, (1987); Smith A., Janak J., Adler R., Electronic Conduction in Solids, Physical and Quantum Electronics Series, (1967); Prigogine I., Introduction to Thermodynamics of Irreversible Processes, (1962); Levy P., Zhang S., Phys. Rev. Lett., 79, (1997); van Hoof J., Schep K., Brataas A., Kelly P., Bauer G., Phys. Rev. B, 59, (1999); Brataas A., Tatara G., Bauer G., Phys. Rev. B, 60, (1999); Brataas A., Tatara G., Bauer G., Philos. Mag. B, 78, (1998); Hirsch J., Phys. Rev. Lett., 83, (1999); Fert A., Cambell I., J. Phys. F, 6, (1996); van Son P., van Kampen H., Wyder P., Phys. Rev. Lett., 58, (1987); Zhang S., Levy P., Fert A., Phys. Rev. B, 45, (1992); Valet T., Fert A., Phys. Rev. B, 48, (1993); Wongsam M., Chanterell R., J. Magn. Magn. Mater., 152, (1996); Gilbert T., Phys. Rev., 100, (1955); Suhl H., IEEE Trans. Magn., 34, (1998); Brown W., Micromagnetics, (1963); Aharoni A., J. Appl. Phys., 10, (1959); Kelly D., Franck A., Gilbert S., Phys. Rev. Lett., 82, (1999); Gilbert S., Scarani V., Kelly D., Doudin B., IEEE Trans. Magn., 34, (1998); Piraux L., Dubois S., Marchal C., Beuken J., Filipozzi L., Despres J., Ounadjela K., Fert A., J. Magn. Magn. Mater., 156, (1996); Coffey W., Crothers D., Dormann J., Kennedy E., Wernsdorfer W., Phys. Rev. Lett., 80, (1998); Wernsdordfer W., Et al., Phys. Rev. Lett., 77, (1996); Wernsdordfer W., Phys. Rev. B, 55, (1997); Kambersky V., Can. J. Phys., 48, (1970); Kambersky V., Czech. J. Phys., Sect. B, 22, (1971)","","","","","","","","","10980121","","","","English","Phys. Rev. B Condens. Matter Mater. Phys.","Article","Final","All Open Access; Green Open Access","Scopus","2-s2.0-7644229909" diff --git a/src/bibx/builders/scopus_csv.py b/src/bibx/builders/scopus_csv.py index 49e771e..074bcd3 100644 --- a/src/bibx/builders/scopus_csv.py +++ b/src/bibx/builders/scopus_csv.py @@ -1,15 +1,28 @@ """CSV based builder for Scopus data.""" import csv -from typing import Annotated, TextIO +import logging +from collections.abc import Generator +from typing import Annotated, Optional, TextIO from pydantic import BaseModel, Field from pydantic.functional_validators import BeforeValidator +from bibx.article import Article from bibx.collection import Collection from .base import CollectionBuilder +logger = logging.getLogger(__name__) + + +def _str_or_none(value: Optional[str]) -> Optional[str]: + return value if value else None + + +def _split_str(value: Optional[str]) -> list[str]: + return value.strip().split("; ") if value else [] + class Row(BaseModel): """Row model for Scopus CSV data.""" @@ -17,10 +30,52 @@ class Row(BaseModel): authors: Annotated[ list[str], Field(validation_alias='"Authors"'), - BeforeValidator(lambda x: x.strip().split("; ")), + BeforeValidator(_split_str), ] - title: Annotated[str, Field(validation_alias="Title")] year: Annotated[int, Field(validation_alias="Year")] + title: Annotated[str, Field(validation_alias="Title")] + journal: Annotated[str, Field(validation_alias="Abbreviated Source Title")] + volume: Annotated[ + Optional[str], + Field(validation_alias="Volume"), + BeforeValidator(_str_or_none), + ] + issue: Annotated[ + Optional[str], + Field(validation_alias="Issue"), + BeforeValidator(_str_or_none), + ] + page: Annotated[ + Optional[str], + Field(validation_alias="Page start"), + BeforeValidator(_str_or_none), + ] + doi: Annotated[ + Optional[str], + Field(validation_alias="DOI"), + BeforeValidator(_str_or_none), + ] + cited_by: Annotated[ + Optional[int], + Field(validation_alias="Cited by"), + BeforeValidator(_str_or_none), + ] + references: Annotated[ + list[str], + Field(validation_alias="References"), + BeforeValidator(lambda x: x.split("); ")), + ] + author_keywords: Annotated[ + list[str], + Field(validation_alias="Author Keywords"), + BeforeValidator(_split_str), + ] + index_keywords: Annotated[ + list[str], + Field(validation_alias="Index Keywords"), + BeforeValidator(_split_str), + ] + source: Annotated[str, Field(validation_alias="Source")] class ScopusCsvCollectionBuilder(CollectionBuilder): @@ -33,10 +88,58 @@ def __init__(self, *files: TextIO) -> None: def build(self) -> Collection: """Build the collection.""" + articles = self._articles_from_files() + return Collection(articles=Collection.deduplicate_articles(list(articles))) + + def _articles_from_files(self) -> Generator[Article]: for file in self._files: - reader = csv.DictReader(file) - print(reader.fieldnames) - for row in reader: - datum = Row.model_validate(row) - print(datum.model_dump_json(indent=2)) - return Collection(articles=[]) + yield from self._parse_file(file) + + def _parse_file(self, file: TextIO) -> Generator[Article]: + reader = csv.DictReader(file) + for row in reader: + datum = Row.model_validate(row) + yield ( + Article( + label="", + ids=set(), + title=datum.title, + authors=datum.authors, + year=datum.year, + journal=datum.journal, + volume=datum.volume, + issue=datum.issue, + page=datum.page, + doi=datum.doi, + times_cited=datum.cited_by, + references=list( + filter( + None, + [ + self._article_from_reference(ref) + for ref in datum.references + ], + ) + ), + keywords=list(set(datum.author_keywords + datum.index_keywords)), + sources={datum.source}, + ) + .add_simple_id() + .set_simple_label() + ) + + def _article_from_reference(self, reference: str) -> Optional[Article]: + try: + *authors, journal, issue, year = reference.split(", ") + _year = int(year.lstrip("(").rstrip(")")) + return Article( + label=reference, + ids={reference}, + authors=authors, + year=_year, + journal=journal, + issue=issue, + ).add_simple_id() + except ValueError: + logger.debug("error parsing reference: %s", reference) + return None From f3a335fd92771867d6204566e6543c994a27e583 Mon Sep 17 00:00:00 2001 From: Oscar Arbelaez Date: Sat, 15 Feb 2025 18:46:07 +0000 Subject: [PATCH 3/5] Add functional test --- tests/builders/test_scopus_csv.py | 8 ++++++++ 1 file changed, 8 insertions(+) create mode 100644 tests/builders/test_scopus_csv.py diff --git a/tests/builders/test_scopus_csv.py b/tests/builders/test_scopus_csv.py new file mode 100644 index 0000000..8f4fe28 --- /dev/null +++ b/tests/builders/test_scopus_csv.py @@ -0,0 +1,8 @@ +from bibx import read_scopus_csv + + +def test_scopus_csv() -> None: + """Test the ScopusCSVBuilder class.""" + with open("docs/examples/scopus.csv") as file: + collection = read_scopus_csv(file) + assert collection is not None From c22426ec09f4de50b0634e928923c293b4f60187 Mon Sep 17 00:00:00 2001 From: Oscar Arbelaez Date: Sun, 16 Feb 2025 12:11:52 +0000 Subject: [PATCH 4/5] Split on ; in the end --- src/bibx/builders/scopus_csv.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/bibx/builders/scopus_csv.py b/src/bibx/builders/scopus_csv.py index 074bcd3..66a5d9e 100644 --- a/src/bibx/builders/scopus_csv.py +++ b/src/bibx/builders/scopus_csv.py @@ -63,7 +63,7 @@ class Row(BaseModel): references: Annotated[ list[str], Field(validation_alias="References"), - BeforeValidator(lambda x: x.split("); ")), + BeforeValidator(_split_str), ] author_keywords: Annotated[ list[str], From 0fd70ae66c5491fee5e802d44acc6b5cb20df087 Mon Sep 17 00:00:00 2001 From: Oscar Arbelaez Date: Sun, 16 Feb 2025 12:12:07 +0000 Subject: [PATCH 5/5] Add verbose option to the cli --- src/bibx/cli.py | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/bibx/cli.py b/src/bibx/cli.py index 97074e4..ad391e9 100644 --- a/src/bibx/cli.py +++ b/src/bibx/cli.py @@ -1,5 +1,6 @@ import logging from enum import Enum +from typing import Annotated import networkx as nx import typer @@ -19,6 +20,17 @@ app = typer.Typer() +@app.callback() +def main( + verbose: Annotated[ # noqa: FBT002 + bool, typer.Option("--verbose", "-v", help="Enable verbose logging.") + ] = False, +) -> None: + """BibX is a command-line tool for parsing bibliographic data.""" + if verbose: + logging.basicConfig(level=logging.DEBUG) + + class Format(Enum): """Supported formats."""