Zn1-xCoxO Diluted Magnetic Semiconductor Bulk Prepared by Hot Pressing

Zn1-xCoxO diluted magnetic semiconductor bulks were prepared by hot pressing. Mixed powders of pure ZnO and CoO were compacted under pressure of 10 MPa at the temperature of 1 073 K. Then the samples were annealed in vacuum at the temperature from 673 K to 873 K for 10 h. The crystal structure and magnetic properties of Zn1-xCoxO bulks have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of zinc and cobalt in the samples. The results showed that Zn1-xCoxO samples had c-axis oriented wurtzite symmetry, neither cobalt or cobalt oxide phase was found in the samples if x was less than 0.15. Zn and Co existed in Zn0.9Co0.1O sample in Zn2+ and Co2+ states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Co-doped ZnO samples. The saturation magnetization and the coercivity of Zn0.9Co0.1O sample, observed in the M-H curve, were about 0.20 emu/g and 200 Oe, respectively.