Enhancement of ferromagnetic properties in Zn_1-xCo_xO by additional Cu doping

Cu-doped ZnO samples were fabricated by the solid-state reaction method for enhancing high-temperature ferromagnetism in the samples. The crystal structures of the samples were characterized using 2θ-θ x-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that small amount of additional Cu doping would create appropriate amount of carriers, thereby enhancing magnetization. The bulk ZnO samples exhibited obvious ferromagnetic ordering above room temperature with additional amount of Cu doping. The results of x-ray and EDX mapping, shows that the Co is homogeneous distribution in the ZnO samples.