MAGNETOCRYSTALLINE ANISOTROPY IN FERROMAGNETIC-FILMS

The magnetocrystalline anisotropy (MA) of ferromagnetic fcc Ni, fcc Co, and bcc Fe (001) slabs is calculated to second order in the spin-orbit coupling constant using realistic tight-binding models with parameters fitted to available first-principles electronic-structure calculations. Results for slabs with 1 - 17 atomic layers show that MA favors magnetization perpendicular to the slab for Fe but in-plane for Ni and Co, in agreement with experiment. Fluctuations in the MA as the thickness is varied indicate that surface MA is not purely of local origin in the surface atomic layer.