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Searching the weakest link: Demagnetizing fields and magnetization reversal in permanent magnets

Scripta Materialia, Vol. 154, Pages 253-258

2018年9月1日(土)

Johann Fischbacher, Alexander Kovacs,Lukas Ex, J. Kuhnel, Eduard Mehofer, SepehriAmin Hossein, Tadakatsu Ohkubo, Kazuhiro Hono,Thomas Schrefl ( https://doi.org/10.1016/j.scriptamat.2017.11.020 )

Abstract

Magnetization reversal in permanent magnets occurs by the nucleation and expansion ofreversed domains. Micromagnetic theory offers the possibility to localize the spots within thecomplex structure of the magnet where magnetization reversal starts. We compute maps ofthe local nucleation field in a Nd2Fe14B permanent magnet using a model order reductionapproach. Considering thermal fluctuations in numerical micromagnetics we can also quantifythe reduction of the coercive field due to thermal activation. However, the major reduction ofthe coercive field is caused by the soft magnetic grain boundary phases and misorientation ifthere is no surface damage.


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文部科学省

文部科学省
元素戦略プロジェクト(活動紹介)
NIMS磁石パートナーシップ

元素戦略拠点

触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
高効率モーター用磁性材料技術研究組合
高効率モーター用 磁性材料技術研究組合