Dipolar relaxation and the impedance of yttria-stabilised zirconia ceramic electrolyte

Equivalent circuit analysis of ac impedance data for yttria-stabilised zirconia ceramics shows evidence for dipole relaxation at intermediate frequencies in addition to the long range, oxide ion conduction. Dipoles, or larger clusters, arise from the association between substitutional Y3+ ions and oxide ion vacancies. Resistance values for dipole relaxation have similar activation energies to those associated with long range conduction through both bulk and grain boundaries, of approximately 1.1 eV, since both processes involve oxide ion migration.