Quasielastic neutron scattering of hydrated BaZr_{0.90}A_{0.10}O_{2.95}   (A = Y and Sc)
  Proton motions in hydrated proton conducting perovskites BaZr_{0.90}A_{0.10}O_{2.95} (A = Y and Sc) have been investigated using quasielastic neutron scattering. The results reveal a localized motion on the ps time scale and with an activation energy of ~10-30 meV, in both materials. The temperature dependence of the total mean square displacement of the protons suggests an onset of this motion at a temperature of about 300 K. Comparison of the QENS results to density functional theory calculations suggests that for both materials this motion can be ascribed to intra-octahedral proton transfers occurring close to a dopant atom. The low activation energy, more than ten times lower than the activation energy for the macroscopic proton conductivity, suggests that this motion is not the rate-limiting process for the long-range proton diffusion, i.e. it is not linked to the two materials significantly different proton conductivities. 
M. Karlsson, A. Matic, D. Engberg, M.E. Bj\"orketun, M.M. Koza, I.   Ahmed, G. Wahnstr\"om, P. Berastegui, L. B\"orjesson an...