Oxidation-induced surface stress on texture development of thin films: The (001) FePt case

Abstract

Residual stress is an inevitable characteristic in all kinds of thin film materials. The incorporation of stress and physical properties may also be of importance as a stress-driven functional characteristics, particularly in the context of engineering texture and anisotropies in magnetic thin film materials. A mechanism explaining the (001) preferred orientation in the rapidly annealed FePt thin films is proposed on the basis of the experimental study of the oxidation-induced surface stress measurements. By adopting a grazing incidence anomalous x-ray diffraction based on synchrotron radiation, the depth-resolved stress distribution of the FePt films was investigated. A substantial in-plane tensile stress induced by surface oxidation was observed in the FePt thin films. The oxidation layer, with an appropriate thickness, maintains the accumulated tensile stress, thereby inducing the (001) preferred orientation in FePt. The surface stress relaxation was observed in the FePt films with the processes lacking oxygen or in a poor vacuum condition.