Ionic conductivity studies on Mg stabilized zirconia by impedance spectroscopy

The high ionic conductivity of stabilized zirconia by substitutional doping of lower valent metal oxides (MgO, CaO, Y2O3, Sc2O3 etc.) found applications in fuel cells, gas sensors etc. The Mg stabilized zirconia has been synthesized by co-precipitation method. The formation of the compound has been confirmed by X-ray diffractogram (XRD) analysis. The electrical characterization is carried out using the impedance spectroscopy method in the frequency range of 50–5 MHz. The conductivity isotherm of the conductance spectra is falling onto one master curve, which suggests a temperature independent relaxation mechanism. The impedance analysis shows depressed semicircles, due to the bulk and grain boundary effects. The bulk and grain boundary resistance of the material has been extracted from the impedance analysis and it is found to be 7.3×104 Ω cm−1 and 2×105 Ω cm−1, respectively, at 773 K. The modulus peak maximum shifts to higher frequency with increase in temperature and broad nature of the peaks indicate the non-Debye nature of the material.