Low-temperature dielectric relaxation peaks involving proton tunneling in Ba1-xNdxCeO3

An investigation of dielectric relaxation at relatively low-temperature (55 -225 K) of the protonic conductor Ba1-xNdxCeO3, for x = 0.05, has revealed a major dielectric relaxation peak, as well as an associated smaller peak, with characteristics that strongly suggest proton tunneling. In particular, the relaxation rate is almost constant between 55 and 85 K. The nature of the dipolar defect that can give rise to such a peak is considered. [S0163- 1829(99)50630-9].