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

• Published in: Journal of magnetism and magnetic materials 2011-03, Vol.323 (6), p.829-832
• Main Authors: Lu, J.J., Lin, T.C., Tsai, S.Y., Mo, T.S., Gan, K.J.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diluted magnetic semiconductor; Electrical properties of specific thin films; Electrical resistance; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; EXAFS; Ferromagnetism; Halls; Ii-vi semiconductors; Magnetic measurement; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Magnetic semiconductors; Magnetron sputtering; Nickel; Physics; Studies of specific magnetic materials; Wurtzite; X-rays; Zinc oxide
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2010.11.025

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 0.39μB/Ni, respectively. The bound-magnetic-polaron mediated exchange is proposed to be the possible mechanism for the room-temperature ferromagnetism in this work. ► Both XRD and XAS results indicated that Ni2+ ions replace Zn2+ ions substitutionally in the host matrix. ► The Zn1−xNixO films with x=0.06 and 0.11 revealed room-temperature ferromagnetism. ► 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.