XPS and Raman scattering studies of room temperature ferromagnetic ZnO : Cu

ZnO and Cu-doped ZnO nanocrystals have been synthesized by a sol-gel method. The nanocrystals have been investigated by XRD and all the particles are found to show the wurtzite structure. X-ray photoelectron spectroscopy and Raman scattering results provide evidence that Cu ions are mainly in the divalent state and incorporated into the ZnO lattice at Zn2+ sites. Magnetic measurements reveal that the as-grown Zn0.9894Cu0.0106O nanocrystals exhibit room temperature ferromagnetic behaviour with the saturation magnetization of 0.0053 emu g-1 and the Curie temperature above 300 K.