Optimization of Nanocomposite Materials for Permanent Magnets: Micromagnetic Simulations of the Effects of Intergrain Exchange and the Shapes of Hard Grains
Optimization of Nanocomposite Materials for Permanent Magnets: Micromagnetic Simulations of the Effects of Intergrain Exchange and the Shapes of Hard Grains
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DOI：
10.1103/physrevapplied.7.014011
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发表时间：
2017-01
影响因子：
4.6
通讯作者：
S. Erokhin;D. Berkov
中科院分区：
文献类型：
--
作者：
S. Erokhin;D. Berkov
在本文中，我们进行了详细的数值分析，在纳米复合磁性材料组成的硬磁颗粒（即，由具有高磁晶各向异性的材料制成的晶粒）嵌入到软磁相中。这种材料广泛用于生产永磁体，因为它们联合收割机高剩磁和大矫顽力。我们进行模拟的纳米复合材料与锶铁氧体作为硬相和铁或镍作为软相，集中我们的努力分析的影响（i）不完善的晶间交换和（ii）的非球形形状的硬晶粒。我们证明，在对比常见的信念，最大的能量产品实现不与一个完美的粒间交换系统，但这种交换大大削弱的材料。我们还表明，磁滞回线的主要参数-剩磁，矫顽力，和能量产品表现出非平凡的依赖于硬颗粒的形状，并提供详细的解释，我们的结果。在这项工作中获得的模拟预测开辟了新的途径，永磁体材料的优化。
In this paper, we perform a detailed numerical analysis of remagnetization processes in nanocomposite magnetic materials consisting of magnetically hard grains (i.e., grains made of a material with a high magnetocrystalline anisotropy) embedded into a magnetically soft phase. Such materials are widely used for the production of permanent magnets because they combine high remanence with large coercivity. We perform simulations of nanocomposites with Sr-ferrite as the hard phase and Fe or Ni as the soft phase, concentrating our efforts on analyzing the effects of (i) the imperfect intergrain exchange and (ii) the nonspherical shape of hard grains. We demonstrate that—in contrast to common belief—the maximal energy product is achieved not for systems with a perfect intergrain exchange, but for materials where this exchange is substantially weakened. We also show that the main parameters of the hysteresis loop— remanence, coercivity, and the energy product—exhibit nontrivial dependencies on the shape of hard grains and provide detailed explanations for our results. Simulation predictions obtained in this work open new ways for the optimization of materials for permanent magnets.