Belozerov A S, Katanin A A, Anisimov V I
M. N. Miheev Institute of Metal Physics, Russian Academy of Sciences, 620108 Yekaterinburg, Russia.
Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia.
J Phys Condens Matter. 2020 Jun 19;32(38). doi: 10.1088/1361-648X/ab9566.
We study the electronic and magnetic properties of L1phase of FeNi, a perspective rare-earth-free permanent magnet, by using a combination of density functional and dynamical mean-field theory. Although L1FeNi has a slightly tetragonally distorted fcc lattice, we find that magnetic properties of its constituent Fe atoms resemble those in pure bcc Fe. In particular, our results indicate the presence of well-localized magnetic moments on Fe sites, which are formed due to Hund's exchange. At the same time, magnetism of Ni sites is much more itinerant. Similarly to pure bcc Fe, the self-energy of Fe 3d states is found to show the non-Fermi-liquid behavior. This can be explained by peculiarities of density of Fe 3d states, which has pronounced peaks near the Fermi level. Our study of local spin correlation function and momentum dependence of particle-hole bubble suggests that the magnetic exchange in this substance is expected to be of RKKY-type, with iron states providing local-moment contribution, and the states corresponding to nickel sites (including virtual hopping to iron sites) providing itinerant contribution.
我们运用密度泛函理论和动力学平均场理论相结合的方法，研究了有望成为无稀土永磁体的FeNi L1相的电子和磁性能。尽管L1-FeNi具有轻微四方畸变的面心立方晶格，但我们发现其组成的Fe原子的磁性能与纯体心立方Fe中的类似。特别是，我们的结果表明Fe位点上存在因洪德交换而形成的局域磁矩。同时，Ni位点的磁性更加巡游。与纯体心立方Fe类似，Fe 3d态的自能表现出非费米液体行为。这可以用Fe 3d态密度的特性来解释，其在费米能级附近有明显的峰值。我们对局部自旋关联函数以及粒子-空穴泡的动量依赖性的研究表明，这种物质中的磁交换预计为RKKY型，铁态提供局域矩贡献，而与镍位点对应的态（包括到铁位点的虚拟跃迁）提供巡游贡献。
