Theory of Defect-Induced Crystal Field Perturbations in Rare-Earth Magnets
Theory of Defect-Induced Crystal Field Perturbations in Rare-Earth Magnets
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DOI：
10.1103/physrevlett.132.056703
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发表时间：
2024-01-31
影响因子：
8.6
通讯作者：
Staunton，Julie B.
中科院分区：
文献类型：
--
作者：
Patrick，Christopher E.;Huang，Yixuan;Staunton，Julie B.
我们提出了一个理论描述的单离子各向异性的稀土（RE）磁铁在点缺陷的存在。以RE-贫磁体类为原型，我们使用第一性原理计算来显示如何引入Ti替代扰动的晶体场，产生新的系数由于较低的对称性的RE环境。然后，我们证明，这些扰动可以非常有效地描述使用屏蔽点电荷模型。我们提供的各向异性能，可以直接实施原子自旋动力学模拟，这意味着这样的模拟可以进行任意排列的点缺陷的解析表达式。这里计算的显着的晶体场扰动表明，从结构的角度来看，是单相的样品仍然可以有一个显着变化的各向异性分布在原子水平上，如果有组成的障碍，这可能会影响本地化的磁性物体，如畴壁或skyrmions。
We present a theory describing the single-ion anisotropy of rare-earth (RE) magnets in the presence of point defects. Taking the RE-leanmagnet class as a prototype, we use first-principles calculations to show how the introduction of Ti substitutions intoperturbs the crystal field, generating new coefficients due to the lower symmetry of the RE environment. We then demonstrate that these perturbations can be described extremely efficiently using a screened point charge model. We provide analytical expressions for the anisotropy energy that can be straightforwardly implemented in atomistic spin dynamics simulations, meaning that such simulations can be carried out for an arbitrary arrangement of point defects. The significant crystal field perturbations calculated here demonstrate that a sample that is single phase from a structural point of view can nonetheless have a dramatically varying anisotropy profile at the atomistic level if there is compositional disorder, which may influence localized magnetic objects like domain walls or skyrmions.