Microscopic origin of the magnetocrystalline anisotropy energy of ferromagnetic-semiconductor multilayers

Results of a detailed study of the spin-orbit-induced electronic magnetocrystalline anisotropy energy (MAE) of Fe/GaAs (001) ferromagnetic-semiconductor multilayers using the first-principles spin-polarized relativistic (SPR) linear-muffin-tin-orbital (LMTO) method are presented. For a further analysis, the spin-orbit-induced orbital moments have been calculated in a spin-resolved way, in addition. This allowed to check the relationship between the MAE and the orbital moments suggested by Bruno and van der Laan. According to that relationship, the microscopic origin of the electronic MAE of these multilayers is mainly due (similar to 80%) to a delicate rearrangement of the occupations of certain 3d minority spin levels at the interface Fe layers.