Impedance study of BICUVOX ceramics

The polycrystalline samples of Bi2V0.9Mg0.1O5.35 were synthesised. The conductivity of the samples with Pt electrodes was determined by non-linear least-squares analysis of the impedance spectra. The total conductivity of the samples exhibits Arrhenius-type dependence on temperature with two straight line sections. In the transition from one linear section to the other a time dependence of conductivity was observed. The conductivity decreases both on heating and cooling during several hours at constant temperature (between 665 and 680K and between 710 and 695K on heating and cooling respectively). During heating at temperatures between 685 and 790K the Arrhenius plot are not linear. It may be expected that a process of slow ordering/disordering of oxygen vacancies is responsible for this phenomenon.