Realization of room temperature ferromagnetism in Zn1−xCrxO thin films grown by RF magnetron sputtering

Chromium doped zinc oxide (ZnO:Cr) films have been deposited onto sapphire substrates by RF magnetron sputtering. The effects of different chromium concentrations (5, 15 and 30 mol%) on structural, morphological and magnetic properties have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM), respectively. According to X-ray diffraction the films are preferentially oriented along (0 0 2) diffraction plane and maintain its wurtzite structure by the addition of Cr even for higher concentration. The FWHM is found to increase initially and it saturates for 15 and 30% of Cr concentration. AFM images reveal that the surface roughness of the films is exponentially decreased upon the addition of Cr. VSM measurement indicates the realization of ferromagnetism at room temperature for the films corresponding to 15 and 30 mol% Cr doped ZnO which suggesting that the sufficient number of Cr ions incorporated to induce the magnetic moment.