Debye-type relaxation in yittria stabilized zirconia

Dielectric relaxation and ac conductivity behavior were investigated for yittria stabilized zirconia (YSZ) compounds with yittria concentration varying from 8 to 12 mol%. Dielectric loss spectrum shows that two types of Debye-type relaxation exist for the YSZ materials with yittria concentration varying in the range of 10–12 mol%. Observed data indicates that both the Debye-type relaxation and ceramics/metallic interface polarization are responsible for very high relative dielectric constant in the low frequency and high temperature range. Debye-type peaks get suppressed due to the predominance of the dielectric loss; this dielectric loss is attributed to the loss current conductivity. Electric modulus spectrum shows that grain and grain boundary offer same capacitance to the ion conduction at high temperatures. The frequency range of dc conductivity extends to higher frequency side as temperature increases.