COERCIVITY MECHANISM OF SINTERED PR17FE75B8 AND PR17FE53B30 PERMANENT-MAGNETS
COERCIVITY MECHANISM OF SINTERED PR17FE75B8 AND PR17FE53B30 PERMANENT-MAGNETS
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DOI：
10.1103/physrevb.50.3849
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发表时间：
1994-08-01
影响因子：
3.7
通讯作者：
ROSSIGNOL, MF
中科院分区：
文献类型：
--
作者：
KOU, XC;KRONMULLER, H;ROSSIGNOL, MF
两个矫顽力模型，Givord等人发展的唯象模型。和Kronmuler等人提出的微磁模型，分析了Pr17Fe75B8和Pr17Fe53B30烧结永磁体的矫顽场随温度的变化规律。并对这两种模型进行了总体比较。微磁模型考虑了颗粒间的错位和颗粒表面的各向异性缺陷。基于该模型的分析表明，Pr17Fe75B8和Pr17Fe53B30烧结永磁体的矫顽力受晶核机制控制，晶核机制优先发生在晶面，此时磁各向异性减小，局部退磁场最大。发现了微磁参数与N(Jeff)之间的简单比例关系。此外，该模型还可以估算颗粒间的磁耦合效应。唯象模型考虑了成核区的几何效应、区壁能扰动的影响和热激活效应。基于该模型的分析表明，反转磁畴的扩展优先发生在磁化壁能较低的区域，且尖峰状反转磁畴在能量上是有利的。研究表明，当成核过程主导磁化反转过程，且颗粒间的磁耦合较弱时，唯象模型与微磁模型近似对应。
Two coercivity models, a phenomenological model developed by Givord el al. and a micromagnetic model developed by Kronmuller et al., have been used to analyze the temperature dependence of the coercive field of sintered Pr17Fe75B8 and Pr17Fe53B30 permanent magnets. A general comparison of these two models is made. The micromagnetic model takes into account the misalignment of grains and the anisotropy imperfections at the grain surface. From the analysis based on this model it follows that the coercivity in sintered Pr17Fe75B8 and Pr17Fe53B30 permanent magnets is controlled by a nucleation mechanism occurring preferentially in the grain surface where the magnetic anisotropy is reduced and the local demagnetizing field is the highest. A simple proportional relationship between the micromagnetic parameters and N(eff) is found. In addition, the effect of magnetic coupling among grains can be estimated with this model. The phenomenological model takes into account the geometrical effect of nucleated domains, the effect of the disturbance of domain-wall energy, and the thermal activation. From the analysis based on this model, it follows that the expansion of reversed domains takes place preferentially in regions where the domain-wall energy is reduced and where a spikelike reversed domain is energetically favorable. It is demonstrated in the present investigation that the phenomenological model corresponds approximately to the micromagnetic model when the nucleation process dominates the magnetization reversal process and the magnetic coupling between grains is weak.