Demagnetization Process of Nd-Fe-B Sintered and Ferrite Magnets

IF 1 4区工程技术 Q4 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEJ Transactions on Electrical and Electronic Engineering Pub Date : 2025-01-24 DOI:10.1002/tee.24264

Yutaka Matsuura

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Abstract

The magnetization reversal mechanism for Nd-Fe-B sintered and ferrite magnets was investigated using magnetic measurements and soft X-ray magnetic circular dichroism microscopy. In magnetization reversal, discrete reversals of crystal grains occurred first in the demagnetized field region, which was lower than the coercivity. In the next step, clusters of reversed grains were formed by reversals in crystal grains around the discrete reversed grains. For highly aligned magnets, the cluster sizes at the coercivity increased with decreasing temperature, and also varied with composition. The alignment and angular dependences of the coercivity varied with cluster size, which depended on the number of discrete magnetization reversal grains that occurred in the demagnetizing field that was lower than the coercivity. Hence, if the number of discrete reversal grains was large, the cluster size was small; conversely, if the number of discrete reversal grains was small, the cluster size was significant. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

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钕铁硼烧结铁氧体磁体的退磁过程

采用磁性测量和软x射线磁圆二色显微镜研究了钕铁硼烧结铁氧体和钕铁硼烧结磁体的磁化反转机理。在磁化反转中，晶粒的离散反转首先发生在退磁区，该区域比矫顽力小。在接下来的步骤中，通过在离散的反向晶粒周围的晶粒反转形成反向晶粒簇。对于高度排列的磁体，矫顽力处的团簇尺寸随温度的降低而增加，也随成分的变化而变化。矫顽力的取向和角度依赖关系随团簇尺寸的变化而变化，这取决于在低于矫顽力的退磁场中出现的离散磁化反转晶粒的数量。因此，离散反转颗粒数量越多，簇大小越小；相反，如果离散反转颗粒的数量较小，则簇大小显著。©2025日本电气工程师协会和Wiley期刊有限责任公司。

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来源期刊

IEEJ Transactions on Electrical and Electronic Engineering 工程技术-工程：电子与电气

CiteScore

2.70

自引率

10.00%

发文量

199

审稿时长

4.3 months

期刊介绍： IEEJ Transactions on Electrical and Electronic Engineering (hereinafter called TEEE ) publishes 6 times per year as an official journal of the Institute of Electrical Engineers of Japan (hereinafter "IEEJ"). This peer-reviewed journal contains original research papers and review articles on the most important and latest technological advances in core areas of Electrical and Electronic Engineering and in related disciplines. The journal also publishes short communications reporting on the results of the latest research activities TEEE ) aims to provide a new forum for IEEJ members in Japan as well as fellow researchers in Electrical and Electronic Engineering from around the world to exchange ideas and research findings.