Dielectric, magnetic and structural properties of Co doped CeO2 powders

Bulk samples of Ce1-xCoxO2 (x = 0.00 to 0.05) are prepared using solid state reaction technique. X-ray diffraction (XRD) results show a continuous decrease in the unit cell volume of Co doped CeO2 samples which indicates the substitutional doping of Co into the CeO2 lattice up to the doping concentration of x = 0.05. Field emission scanning electron microscopy (FESEM) images depict the formation of close packed particles of unusual morphology of size of 1-3 mu m. X-ray absorption spectroscopy (XAS) at Ce M5,4 edge and Co L3,2 edge confirm the presence of Ce4+ and Co2+ ions, respectively. O K edge XAS conveys modification in electronic structure properties via formation of oxygen ion vacancies upon Co doping concentrations. Our results show that the observed large dielectric constants (epsilon ' and epsilon") and room temperature ferromagnetism are the intrinsic properties of the Co doped CeO2, which may offer this material in dielectric and magnetic devices applications.