Study of the O K-edge XANES of Cobalt-doped ZnO diluted magnetic semiconductors

Abstract

Cobalt-doped ZnO samples were prepared by both sol-gel and magnetron sputtering methods, respectively. Co atoms have incorporated into the ZnO lattice and located at the substitutional sites of the Zn atoms in all samples, while the sol-gel prepared Zn1-xCoxO samples show paramagnetism and the sputtering prepared CoyZn1-yO samples appear ferromagnetism. The calculated O K-edge X-ray absorption near edge structure (XANES) can commendably reproduce all of the peaks observed in CoyZn1-yO samples when one Zn interstitial atom (Zn i) nears the central O atom. Compared with the magnetic properties, it is shown that the Zn interstitial atoms play a key role to the observed ferromagnetism in CoyZn1-yO samples. © 2009 IOP Publishing Ltd.