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

中文翻译：

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寻找最薄弱的环节：永磁体中的去磁场和磁化反转

摘要 永磁体的磁化反转是由反转畴的成核和扩展引起的。微磁理论提供了在磁体的复杂结构中定位磁化反转开始的位置的可能性。我们使用模型降阶方法计算 Nd2Fe14B 永磁体中局部成核场的图。考虑到数值微磁中的热波动，我们还可以量化由于热激活引起的矫顽场的减少。然而，如果没有表面损伤，矫顽场的主要减小是由软磁晶界相和取向错误引起的。