Influences of Oxygen Partial Pressure on the Cu Metal Clustering and Room Ferromagnetism of the (In0.89Fe0.06Cu0.05)2O3 Films

Abstract

The influences of oxygen partial pressure on the local structure, magnetic, and transport properties of (In0.89Fe0.06Cu0.05)2O3 films deposited by different Ar–O2 flow rate (10:0, 10:0.4, and 10:3.0) were studied systematically by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), Hall effect, room temperature (RT) magnetic measurements, and first-principles calculations. The detailed structural analyses indicate that the doped Fe atoms substitute for In3+ sites of the In2O3 lattices with +2 and +3 mixture valences for all the films. However, the majority of codoped Cu atoms form the Cu metal clusters in the film deposited at oxygen flow rate of 0 sccm. With increasing oxygen partial pressure, the Cu metal clusters completely disappear and all the Cu atoms are incorporated substitutionally into the In2O3 lattices at In sites. All the films exhibit intrinsic RT ferromagnetism, and Mott variable range hopping (VRH) transport behavior. The saturation magneti...