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Magnetization reversal process of anisotropic hot-deformed magnets observed by magneto-optical Kerr effect microscopy

Journal of Alloys and Compounds Vol.771, Pages 51-59

2019年1月15日(火)

Marko Soderžnik, Jiangnan Li, Lihua Liu, Hossein Sepehri-Amin, Tadakatsu Ohkubo, Noritsugu Sakuma, TetsuyaShoji, Akira Kato, Schrefl Thomas, Kazuhiro Hono ( https://doi.org/10.1016/j.jallcom.2018.08.231 )

Abstract

Magnetization reversals of hot-deformed (HD) and eutectic alloy diffusion processed hot-deformed (DPHD) magnet with the coercivities of 0.84 T and 2.21 T, respectively, have beeninvestigated by means of magneto-optic Kerr effect microscopy and micromagneticsimulations. In the HD magnet, magnetization reversal starts from misaligned coarse grainslocated at the interface of initial flakes. At a higher magnetic field, the reversed domains showcascade propagation in the vertical direction to the applied magnetic field (c-axis) through theexchange-coupled grains due to weak pinning. Although magnetization reversal also starts frommisaligned grains in DPHD magnet, magnetic domains propagate along the external magneticfield because of the stray filed from reversed grains and strong pinning to the lateral directiondue to the formation of non-ferromagnetic grain boundary phase hindering cascade domainwall propagation. Our micromagnetic simulation results indicate that the removal of misalignedgrains in the anisotropic hot-deformed magnets combined with the formation of non-ferromagnetic grain boundary phase are the key to develop higher coercivity anisotropic hot-deformed Nd-Fe-B magnets.



研究活動

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