Structural and Magnetic Properties of Zn1-xFexO Thin Films Synthesized by RF Magnetron Sputtering

Abstract

This study reports the structural and the magnetic properties of Zn1-xFexO (ZnFeO) films with Fe composition ratios of 0.03 - 0.07. High-quality Zn1-xFexO thin films with a mean thickness of 500 nm were fabricated on alpha-sapphire (0001) substrates by RF magnetron sputtering. The structures of the ZnFeO thin films were examined using various techniques. X-ray diffraction revealed the films to have a well-ordered wurtzite structure without any extra phases. However, the ZnO (0002) diffraction peak shifted gradually from 2 theta = 34.378 degrees to 34.142 degrees with increasing Fe concentration from 0.03 to 0.07. This corresponds to a lattice constant increase of 0.035 angstrom. X-ray photoelectron spectroscopy (XPS) measurements were employed to characterize the valence state of the Fe ions in the films. The XPS revealed the coexistence of Fe3+ and Fe2+ ions in the films. The DC-magnetization measurements demonstrated that the ZnFeO films were ferromagnetic at 5 K.