NdFeB/α-Fe纳米复合永磁材料矫顽力的微磁学模拟

假定弱磁晶间相和结构缺陷在纳米复合永磁材料的硬-硬、硬-软、软-软晶粒间均匀分布,且二者在不同晶粒间的性质和厚度均相同。研究了这类材料的矫顽力机理及其晶间相对材料矫顽力的影响。结果表明,软-软、软-硬、硬-软、硬-硬晶粒间均存在畴壁位移的钉扎场,而材料的矫顽力由硬-硬晶粒边界畴壁位移的钉扎场决定,且材料矫顽力随着晶相厚度d的增大而增大,而随着晶间相各向异性常数K1(0)的增大而减小。当K1(0)为0.8Kh(Kh为硬磁性相正常的磁晶各向异性常数),d在1~2nm范围内变动时,材料的矫顽力与实验结果符合得很好。

Micromagnetic simulation on coercivity of NdFeB/α-Fe nanocomposite permanent magnetic material

Suppose that the weak magnetic intergranular phase and structure defects distribute uniformly between the hard-hard, hard-soft, soft-soft inter-grain for nanocomposite permanent magnetic material, and their properties and thickness are the same between different grains. Thus material coercivity mechanism and the effects of intergranular phase on coercivity are investigated in this paper. The results indicate that the pinning fields of domain wall displacement exist between hard-hard, hard-soft, and soft-soft inter-grain. However, the coercivity of material is determined by the domain wall displacement pinning fields of hard-hard inter-grain. Coercivity increases with increasing intergranular phase thickness d, but decreases with increasing intergranular phase anisotropy constant K1(0). When K1(0) is 0.8Kh (Kh is normal magnetic crystal anisotropy constant of hard magnetic phase) and d changes between 1nm and 2nm, the coercivity of material accords well with experiment results.