Abstract Coercivity in rare-earth permanent magnets depends on the size and shape of magnetic grains. Recent experimental studies have revealed that, however, atomic scale structures around the grain-boundaries of magnets also play a crucial role to determine their coercivity. In this paper, we construct an effective spin model for the Nd2Fe14B structure based on first-principles calculations to describe atomistic magnetization dynamics of the magnetic grains, incorporating the information of the electronic states of the system. We find that the Nd ions located on the surfaces of the grains may have planar magnetic anisotropy, and that they can cause coercivity reduction.

中文翻译：

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在 Nd-Fe-B 磁铁中桥接原子磁性和矫顽力

摘要 稀土永磁体的矫顽力取决于磁粒的大小和形状。然而，最近的实验研究表明，磁铁晶界周围的原子尺度结构也对确定其矫顽力起着至关重要的作用。在本文中，我们基于第一性原理计算构建了 Nd2Fe14B 结构的有效自旋模型，以描述磁性颗粒的原子磁化动力学，并结合系统的电子状态信息。我们发现位于晶粒表面的 Nd 离子可能具有平面磁各向异性，它们会导致矫顽力降低。