论文标题
新近原子的表面磁各向异性对新近磁化磁体固体性的影响
The effect of the surface magnetic anisotropy of the neodymium atoms on the coercivity in the neodymium permanent magnet
论文作者
论文摘要
ND永久磁铁（nd $ _ {2} $ fe $ _ {14} $ b）是现代能源转换设备中使用的必不可少的材料。在有限温度下实现高强度是一个燃烧的问题。控制强制力的重要成分之一是磁性晶粒的表面特性。第一原理研究报告说，面对真空的第一个（001）表面层中的ND原子具有垂直于$ c $轴的平面各向异性，这可能会降低矫正率。着眼于表面各向异性对强制性的影响，我们通过使用反映使用随机Landau-lifshitz-gilbert方程方法的原子模型来检查零和有限温度下的固定性。我们研究了三种情况，其中表面层中的ND原子具有（1）无各向异性，（2）面内各向异性和（3）两种表面（001）和（100）表面的增强各向异性。我们发现，与零温度的情况相反，由于热波动效应，仅修饰第一表面层对有限温度下的矫正作用几乎没有影响。但是，几层的修饰会产生重大影响。我们讨论了强制性对温度，表面类型和修饰层深度的依赖性的细节，以及磁化逆转中域生长的特征。
The Nd permanent magnet (Nd$_{2}$Fe$_{14}$B) is an indispensable material used in modern energy conversion devices. The realization of high coercivity at finite temperatures is a burning issue. One of the important ingredients for controlling the coercive force is the surface property of magnetic grains. It has been reported by first-principles studies that the Nd atoms in the first (001) surface layer facing the vacuum have in-plane anisotropy perpendicular to the $c$ axis, which may decrease the coercivity. Focusing on the surface anisotropy effect on the coercivity, we examine the coercivity at zero and finite temperatures by using an atomistic model reflecting the lattice structure of the Nd magnet with a stochastic Landau-Lifshitz-Gilbert equation method. We study general three cases, in which the Nd atoms in surface layers have (1) no anisotropy, (2) in-plane anisotropy, and (3) reinforced anisotropy for two types of surfaces, (001) and (100) surfaces. We find that in contrast to the zero-temperature case, due to the thermal fluctuation effect, the modification of only the first surface layer has little effect on the coercivity at finite temperatures. However, the modification of a few layers results in significant effects. We discuss the details of the dependence of the coercivity on temperature, type of surface, and modified layer depth, and also the features of domain growth in magnetization reversal.
