Mechanical relaxation measurements in the protonic conductors SrCeO3 and SrZrO3

Abstract

Several mechanical relaxation peaks have been observed in the ceramic proton conductors SrCe1 - xYbxO3 - α and SrZr1 - xYbxO3 - α (x = 0.025, 0.05, 0.1). The spectra consist of a superposition of peaks which can be attributed to defect clusters containing both protons and dopant atoms. These peaks are positioned near 0 °C for a typical measuring frequency of 300 Hz. For the cerates another relaxation contribution shows up near 100 °C. This can be related to oxygen vacancies near a dopant atom. Average activation energies of 0.5 eV for the proton related and 0.8 eV for the oxygen vacancy related local diffusion jumps are derived. © 1995.