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Preparation of Zn0.90Co0.10O Thin Films by r. f. Magnetron Sputtering

Musa M. Can ,  Tezer Fırat ,  Şadan Özcan 

Hacettepe University (HU), Ankara 06800, Turkey


In this work, Zn0.90Co0.10O diluted magnetic semiconductors (DMS) synthesized by mechanical milling and thermal treatment. The formation of solid state reaction was monitored by differential thermal and thermo gravimetric methods (DT-TGA). Substitution of Co+2 ions with Zn+2 host atoms in ZnO lattice had been analyzed by using X-Ray Diffractometer (XRD), Fourier Transform Infrared (FT-IR) and X-Ray Photo Spectroscopy (XPS). Additionally, the impurity phases such as CoO, Co3O4 and ZnCo2O4 or Co clusters have not been detected in the samples. However, in the samples, about 1% tungsten (W) impurity from the mortar of the mill was observed in the form of ZnWO4 .

The prepared Zn0.90Co0.10O semiconductors pressed under a force of 25tons to form 2inch diameter target. Then, by using this target, thin films were grown on sapphire (α-Al2O3) substrate that is ordered in (0001) direction. The structural studies have been done by XRD, Energy Dispersive X-Ray Spectrometry (EDS) and XPS. It is found that ZnO single crystal with (0002) orientation, coherent to the substrate structure, has been obtained. XPS results have shown that there is ~15.6eV energy difference between Co2p1/2 and Co2p3/2. This proves that Zn atoms were replaced by Co atoms in the host ZnO matrix due to this energy difference. XPS results demonstrated that the grown ZnO single crystal film does not have impurity phases such as CoO and Co3O4.  Also Co clusters have not been observed and homogeneity of Co atoms in the lattice has been shown.  The magnetic behavior of the thin films was studied using a vibrating sample magnetometer (VSM).  Magnetic field versus magnetization measurements in field range of ±2 T at 10K and 300K temperatures, and temperature versus magnetization measurements between 10K and 300K in 10kOe applied magnetic field was performed. In the light of the results obtained, the suitability of Zn0.90Co0.10O diluted magnetic semiconductors for the spintronic applications were investigated.


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Presentation: Poster at E-MRS Fall Meeting 2009, Symposium E, by Musa M. Can
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-11 14:31
Revised:   2009-06-07 00:48