Pulsed laser ablation of preferentially orientated ZnO:Co diluted magnetic semiconducting thin films on Si substrates

ZnO:Co thin films with room-temperature ferromagnetism have been synthesized on (001) Si substrates by pulsed laser deposition using a Zn0.95Co0.05O ceramic target. Single-phase wurtzite thin films with (002) preferential orientation were grown at 450°C in vacuum. There is no indication of Co nanocluster formation. However, copious edge dislocations appear to have formed during the film growth. A saturation magnetization of 1.04μB∕Co and a coercivity of 25Oe were obtained at room temperature. In addition to O vacancies, the Zn interstitial induced by edge dislocations may also contribute to the ferromagnetic properties in this oxide-diluted magnetic semiconductor.