Mössbauer spectroscopy data showed that the Eu ions in SrCe0.9Eu0.1O3, annealed at 1273K in air and H, were present as Eu(III). The activation energy for oxide-ion conduction in Eu-doped samples was smaller than that in Yb-doped ones. This was attributed to a larger free volume, and a larger critical radius at the saddle-point. The transport number of oxide ions in SrCe0.9Eu0.1O3 increased with decreasing temperature, and became equal to unity at about 873K. The electrical conductivity of SrCe0.9Eu0.1O3 increased with increasing H partial pressure; thus indicating the occurrence of protonic conduction. The activation energy changed at about 1023K, and this was attributed to the evolution of water vapour.

Electrical Conduction in SrCeO3 Doped with Eu2O3. T.Tsuji, T.Nagano: Solid State Ionics, 2000, 136-137, 179-82