Thickness dependent physical properties of evaporated permalloy/GaAs(100) thin films

Abstract

Thermally evaporated Permalloy Ni80Fe20(Py) thin films on GaAs (100) substrates, for thickness ranging from 132 to 277 nm, are studied. The effect of Py thickness on their physical properties is examined. In order to determine their structure, microstructure, surface morphology, chemical compositions and electrical properties, the deposited Py films were analyzed by X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive X-ray analyzer (SEM-EDS), atomic force microscopy (AFM) and the Hall Effect measurement system (HMS-5300) tools. The obtained X-ray diffraction spectra showed that all samples crystallize in FCC structure with <111> preferred orientation. The grain size and lattice parameter increase with increasing thickness. SEM micrographs revealed very dense structure without micro-cracks and very fine spherical grain distribution. AFM images showed a very smooth surface for all deposited Py films. Electrical measurements revealed that the electrical resistivity and the magnetoresistance decrease with increasing film thickness, while mobility increases.