Structure, Morphology and Magnetization of Fe-Pd Thin Films

Abstract

Several Fe100−xPdx thin films with x = 24–35 have been investigated to understand their structural, morphological and magnetic properties. The lattice spacing d111 obtained from the X-ray diffraction peaks shows a gradual increase with increasing x and this behaviour is attributed to the increasing substitution of Pd with larger atomic radius. While the atomic force microscopy images on selected samples showed surface roughness in the range 2–4 nm the scanning electron microscopy image of a Fe71Pd29 sample showed slightly dark and bright regions due to the large undulations of the surface of the films. We presume that these undulations are due to shape memory twin variants. In-plane magnetization measurements were carried out on selected films in applied magnetic fields up to 30 kOe. For three samples, the saturation magnetization is about 1300 emu/cc whereas for the Fe71Pd29 film it is about 950 emu/cc. The remanence ratio of the films is approximately in the range 50–70%. The behaviour of coercivity of our samples is believed to be due to grain size effect that generally plays a predominant role in thin films with nanometer size grains.