Strong dependence of the Fe thin-film magnetic anisotropy on the Si(111) substrate preparation

We report on the influence of the Si(111) surface preparation on both the structural and the magnetic properties of iron thin films grown onto them. Two different substrate preparation procedures were used, in one of which the substrate was purposely oxidized. The surface analysis was performed by using atomic force and scanning tunneling microscopies, and the magnetic behavior of the films was observed by magneto-optic Kerr effect polarimetry. A strong relationship between the substrate preparation procedure, morphology, and the magnetic response of the iron films was found. A phenomenological model was used to interpret the experimental magnetization data and to derive the anisotropy parameters for both types of Fe samples. It was found that the magnetic response of the film grown onto the oxidized substrate is dominated by the uniaxial anisotropy originated from the substrate topology (a terracelike structure); the behavior of the other film, grown onto the unoxidized substrate, is determined by both c...