Characterization and impedance study of Ba2CeZrO6 double perovskite

Double perovskite oxide Ba2CeZrO6 is synthesized by sol-gel technique for the first time. The X-ray diffraction pattern at room temperature show that the sample exists in single phase and crystallizes in cubic structure with space group The lattice parameter is found to be 0.8635 nm. A scanning electron micrograph image of the Ba2CeZrO6 sample show uniform distribution of grains size ranging from 2.4 to 3 mu m. EDAX spectra showed that Ba2CeZrO6 sample contains only Ba, Ce, Zr and O elements which are closer to stoichiometric ratio. Fourier transform infrared spectra of Ba2CeZrO6 showed the peaks observed corresponds to CeO6 and ZrO6 octahedra indicates the formation of double perovskite structure. The tolerance factor (t) of Ba2CeZrO6 sample is 0.90 suggests unit cell has a small distortion from ideal cubic structure. Frequency (100 Hz-5 MHz) dependent impedance spectroscopy studies were carried out at different temperatures ranging from room temperature to 400 A degrees C. The decrease in impedance (Z), relaxation time (tau) and grain, grain boundary resistance and increase in conductivity with increase in temperature shows the semiconducting nature of the Ba2CeZrO6 sample. Nyquist analysis showed the contribution of grain and grain boundary resistances for the relaxation process in Ba2CeZrO6 sample. The relaxation mechanism in the sample is found to be independent of temperature. The activation energy of Ba2CeZrO6 sample is found to be 0.38 eV.