Magnetic properties of ZnO:V films formed by pulsed laser deposition with bias voltage application

Abstract

Magnetic properties of ZnO films doped with V atoms (a 3d transition metal) were investigated by fabricating specimens using pulsed laser deposition (PLD) with bias voltage application. Electron concentrations of the ZnO:V films were changed by two methods: one was to dope with conventional n-type and p-type impurities, and the other was to change native (donor-type) defect concentrations by applying bias voltages during the film deposition. In M-H curves, smaller magnetization was observed for the film with a low electron concentration (5×1016 cm−3) and it increased linearly with the applied magnetic field, while larger magnetization was observed for the film with a medium electron concentration (5×1018 cm−3) and it exhibited a saturation at about 3 kOe. The saturation magnetization had maximum values for the electron concentrations of 1×1018–5×1018 cm−3 for the films formed by using either dopant impurities or PLD bias voltages. Anomalous Hall effect measurement of the films showed that the convergence of the Hall resistivity occurred at the same magnetic field as where the saturation of the magnetization occurred in the M-H curve.