Structural, magnetic and transport properties of Ni-doped ZnO films

In this work, Ni-doped ZnO (Zn1-xNixO, x=0, 0.03, 0.06, 0.11) films were prepared using magnetron sputtering. X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), temperature dependence electrical resistance, Hall and magnetic measurements were utilized in order to study the properties of the Ni-doped ZnO films. XRD and XAS results indicate that all the samples have a ZnO wurtzite structure and Ni atoms incorporated into ZnO host matrix without forming any secondary phase. The Hall and electrical resistance measurements revealed that the resistivity increased by Ni doping, and all the Ni-doped ZnO films exhibited n-type semiconducting behavior. The magnetic measurements showed that for the samples with x=0.06 and 0.11 are room-temperature ferromagnetic having a saturation magnetization of 0.33 and 0.39 mu(B)/Ni, respectively. The bound-magnetic-polaron mediated exchange is proposed to be the possible mechanism for the room-temperature ferromagnetism in this work. (C) 2010 Elsevier B.V. All rights reserved.