Dielectric Relaxations of Y-Doped ZrO2 Single Crystal

Frequency dependences of dielectric constant (εr′) for 9 mol% Y2O3 doped ZrO2 (YSZ) single crystal which is a typical oxide-ion conductor was successfully explained by the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. Three kinds of Debye-type polarizations were observed at fairly high temperatures. The two polarizations were ascribed to defect associates, (YZr′-VO••)•, which were observed in the tan δ spectra. The third polarization in the high frequency region was ascribed to a long range migration of oxygen vacancy, which was observed in the M″ spectra. The σac dispersion was also explained by the Debye-type polarizations.