Electrical conductivity relaxation in thin-film yttria-stabilized zirconia

We report on complex admittance measurements on ${\mathrm{ZrO}}_{\mathrm{2}}{\mathrm{:Y}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{3}}$ (YSZ) thin films in the parallel plate geometry. Highly textured YSZ thin films, grown by rf sputtering, allow measuring complex admittance free of the effect of charge blocking at grain boundaries. We have examined low-temperature (close to room temperature) regime dominated by association of oxygen vacancies. Complex admittance analyzed in terms of the modulus formalism supplies information on correlation effects in ion motion and allows obtaining an association energy for the oxygen vacancies of 0.45 eV, in agreement with previous theoretical calculations.