Mechanical relaxation peaks were studied in the proton conductors, SrCe1-xYbxO3 and SrZr1-xYbxO3, where x was equal to 0.025, 0.05 or 0.1. The spectra consisted of superposed peaks which were attributed to defect clusters that contained both protons and dopant atoms. These peaks were situated near to 0C at a typical measurement frequency of 300Hz. In the case of SrCe1-xYbxO3, another relaxation contribution appeared near to 100C. This was attributed to O vacancies near to a dopant atom. Average activation energies of 0.5 and 0.8eV were deduced for proton-related and for O vacancy-related local diffusion jumps, respectively.

L.Zimmermann, H.G.Bohn, W.Schilling, E.Syskakis: Solid State Ionics, 1995, 77, 163-6