Ferromagnetic Thin Films with Single-Ion Uniaxial Surface Anisotropy

Abstract

A ferromagnetic thin film with single-ion uniaxial surface anisotropy is studied using Green's function technique for the whole range of anisotropy strength. Allowing that the surface anisotropy on both sides of the film is different in strength, the layer magnetization and the Curie temperature are calculated as a function of the anisotropy of the substrate side by fixing the free-surface anisotropy at a strong or weak value. The results show that, for the case with strong free-surface anisotropy, the thermodynamic behavior of the film is driven by the free-surface, while for the case with weak anisotropy on both sides, it is mainly determined by inner layers.