Abstract
Frequency dependences of the dielectric constant (εr′) were investigated for the perovskite-type oxide BaCe0.9Y0.1O3-δ, which is a typical proton conductor. Numerical calculation of the frequency dependence of εr′ clarified that the large εr′ originated from the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. The Debye-type polarizations which originated from the dopant-vacancy associates, (YCe′-VO••)• were depressed under wet Ar atmosphere. Therefore, it can be speculated that the proton may occur according to the following equilibrium equation: H2O+VO••⇔2H•+OO×.
