Contributions of magnetic properties in epitaxial copper-doped ZnO
Abstract
Diluted magnetic semiconductors have great potential in applications for biological detection and spintronics. However, the origin of magnetism is complex and it is of significant importance to clarify the contributions from various origins. We prepared epitaxial copper-doped ZnO films and investigated the origin of ferromagnetism by combining various characterization methods. The results show that, with nominal Cu concentrations of up to 7.3 at.%, the Cu atoms substitute for the Zn atoms and form strong covalence bonds (CuZn–O), which show a property commensurate with that of the Zn–O bonds in the ZnO host. With further increases in Cu concentrations, the substitutional CuZn effect is obscured, and the [CuZnO4] clusters, regulated by the wurtzite ZnO host, segregate into CuO phase after