Anelastic and dielectric relaxation measurements in the protonic conductor Ba-3(Ca1.18Nb1.82)O9-delta

In order to study the local proton motion in complex perovskite-type protonic conductors anelastic and dielectric relaxation measurements have been carried out on the compound Ba-3(Ca1.18Nb1.82)O9-delta. Both techniques show spectra depending on the proton concentration. From the dielectric measurements an activation energy of E-a = 0.50 eV for the local reorientation of a proton-related defect can be derived. The observed anelastic spectra support the assumption that the same type of defect gives rise to an anelastic relaxation peak. The concentration dependence and comparison with long-range conductivity data are discussed.