The diffusivity of protons in Sc3+-doped single crystals was determined by using infra-red absorption techniques at temperatures ranging from 400 to 750C. The proton diffusion coefficient was evaluated by making sudden changes in the H2O partial pressure or by changing between H+ and D+ vapor. It was found that the proton diffusivity which was estimated for these monocrystals was lower than that reported for ceramic samples. The activation energy for proton diffusion which was deduced by using the first method above was larger than that for ceramic samples. On the basis of these results, it was suggested that the defect concentration or distribution in ceramic grains might be different to that in monocrystals.

H.Yugami, Y.Shibayama, T.Hattori, M.Ishigame: Solid State Ionics, 1995, 79, 171-6