Zn_1−xCo _xO diluted magnetic semiconductor bulk prepared by hot pressing

Abstract

Zn_1−xCo _xO 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 Zn_1−xCo _xO 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 Zn_1−xCo _xO 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 Zn_0.9Co_0.1O 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 Zn_0.9Co_0.1O sample, observed in the M-H curve, were about 0.20 emu/g and 200 Oe, respectively.

Keywords

hot pressing / diluted magnetic semiconductors / Zn_1−xCo _xO

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