Dependence of magnetisation and magnetocrystalline anisotropy on site distribution of alloying elements in RE-TM phases with ThMn12 structure

The effect of site disorder (originating from the presence of substitutional atoms) on intrinsic magnetic properties of intermetallic phases derived from the ThMn12-type crystal structure has been studied using the tight-binding linear-muffin-tin-orbital atomic-sphere approximation (TB-LMTO-ASA) method of density functional theory (DFT). The focus was put on the analysis of magnetisation and magnetocrystalline anisotropy in 42 inequivalent configurations that differed in their arrangements of the substitutional atoms. The first-order anisotropy constant K1 turns out to be far more sensitive to the site occupancy than the magnetisation M. Addition of light interstitial atoms B, C or N gives rise to much higher K1 values but the same range of scattering is retained. As the anisotropy constant K1 is strongly increased by interstitial atoms, the influence of the atomic disorder is less pronounced for these systems.