纳米复合永磁材料中软磁性相交换硬化的研究

Magnetic hardening of soft phase in nanocomposite permanent magnetic materials by exchange coupling

本文就纳米复合永磁材料中软磁相被交换硬化问题,从一维模型和三维模拟计算进行了分析研究.一维和三维各向异性样品研究表明,在相同微结构下,当硬磁相的各向异性降低时,除矫顽力降低外,在磁矩全部反转之前退磁曲线是一样的.因此,硬磁相各向异性的降低不会导致最大磁能积(BH)max增大和剩磁增加.对于三维各向同性样品的模拟计算表明,降低硬磁相的各向异性会使剩磁和(BH)max都明显降低.因此,增强硬磁相的各向异性并增大硬磁相晶粒尺寸是提高纳米复合永磁材料磁性能的一个有效方法.

In this work,the issue of magentic hardening of soft phase in nanocomposite permanent magnetic materials has been investigated using one-and three-dimensional models. For the same microstructure,it is found that the coercivity is decreased and the low-field demagnetization curve keeps unchanged when the anisotropy constant of magnetic hard phase is decreased in anisotropic one-or three-dimensional samples. Therefore,the drop in anisotropy of magnetic hard phase will not lead to the increase of remanence and maximum energy product （BH） max. According to the simulation results of isotropic three-dimension samples, both the remanence and （BH） max will be obviously decreased by the drop in anisotropy. As a result,enhancing the anisotropy and/or enlarging the grain size of magnetic hard phase is one of the means to improve the hard magnetic properties of nanocomposite permanent magnetic materials.