Ab initio Calculations of the Magnetocrystalline Anisotropy in UAuSb_2 Ferromagnet

摘要

The paper presents results of ab initio calculations of the magnetocrystalline anisotropy of UAuSb_2, a strongly anisotropic ferromagnet below 36 K. The total energy of the unit cell of UAuSb_2 was calculated by two methods: the full potential linear muffin-tin orbitals method and by the full-potential local-orbital minimum basis band structure code. The computations were done for the following quantization directions in the tetragonal unit cell (orientations of the magnetization vector M): [010], [001], [011], [110], [111], and [11 1/2] . The anisotropic contribution to the total energy for various directions were fitted by the least-squares procedure to the expression for the magnetocrystalline energy suitable for tetragonal symmetry E_A = K(α_x~4 + α_y~4) + K_2α_z~2, where (α_x,α_y, α_z) is a unit vector along the direction of magnetization M. The band structure calculations predict the direction [111] as the easy axis of magnetization. Values of the calculated anisotropy constants at T = 0 are provided.