磁性纳米颗粒膜的微磁学模拟

Micromagnetics study of the magnetic nano-granular films

用微磁学方法对磁性纳米颗粒膜的磁特性进行了模拟,采用的模型是由122个磁性纳米颗粒组成的面心立方(fcc)结构体系.结果表明:在该体系中,偶极相互作用对体系的静态磁结构的影响显著,而交换相互作用的影响表现不明显.在此基础上,本文还采用有效媒质理论计算分析了磁性合金颗粒不同体积比时颗粒膜的磁谱和表征电磁参量发生显著变化的逾渗现象和逾渗阈值.并完成了对高磁损耗磁性纳米颗粒膜的材料设计.

The nano-granular magnetic films were investigated using the micromagnetics method in this paper. The nano-granular magnetic film model studied consisted of an aggregate of 122 spherical nano-granules with an fcc structure. The computational results showed that the effect of the dipolar interaction of the system on the static magnetic structure is remarkable, while the effect of exchange interaction is indistinc. The frequency dependent permeability spectra of granular films with different volume ratio of magnetic components were simulated and the percolation phenomena of nanostructural magnetic films were extensively analyzed. Thus, the percolation threshold of the system studied was obtained according to the effective medium theory. Furthermore, the design of nano-granular magnetic films with large magnetic losses were carried out.