Study of structure and magnetic properties of Ni-doped ZnO-based DMSs

Zn1−xNix  O (x=0.01x=0.01, 0.02 and 0.05) powders were prepared by a sol–gel method. We have studied the structure and magnetic properties of the samples by using X-ray diffraction (XRD), Raman scattering, superconducting quantum interference device (SQUID) and extended X-ray absorption fine structure (EXAFS). The SQUID results showed that all the samples exhibit ferromagnetism above room temperature. From the XRD spectra of the samples, it was obvious that there had no second phase while the Ni-doped concentration was lower than 5 at%. Raman spectra showed an additional band, which is related to the vibration of Ni dopant. The EXAFS was used for the Ni K-edge to probe the local structures of the Ni dopant in ZnO, which show that Ni dopant was substituted for Zn atoms position up to 5 at% Ni concentration.