Influence of Zr substitution on the electrical and dielectric properties of the Ce0.6-xZrxY0.4O2-δ solid solutions

The influence of Zr4+ substitutions on Ce0.6-xZrxY0.4O2-delta compositions with x = 0, 0.2, 0.4, and 0.6 are studied. Mechanical milling is used to prepare the samples and analyzed its electrical and dielectric properties. The bulk ionic conductivity decreases significantly with the substitution of Zr4+, whereas the grain boundary conductivity increases for x = 0.2, and thereafter decreases. With the increase in temperature, oxide ion conductivity increases which may be due to the separation of oxygen vacancies from the defect associates. Dielectric analysis exhibited the presence of two relaxation peaks due to the ionic conduction in the bulk and grain boundary at high and low frequencies. The energy needed for the dissociation of oxygen vacancies from the defect pairs and the migration energy for the movement of the oxide ions are calculated from the Arrhenius plot of temperature dependent tan delta maxima and the resonance frequencies of the relaxation peaks.