Investigation of the protonic conduction in Sm doped BaCeO3

In the present work the structural and electrical properties of samarium-doped barium cerate perovskites of BaCe1−xSmxO3−δ formula (with x = 0–0.2), prepared by following the solid state reaction method, are investigated. The crystal structure and microstructure of the samples is determined by employing the techniques of X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). According to the XRD analysis at 0 ≤ x ≤ 0.2 the formed continuous series of BaCe1−xSmxO3−δ solid solutions have the structure of cubic perovskite with orthorhombic distortions. It was found that the relative density of the samples is ∼87% for 0.02 < x < 0.05 and ∼94% for 0.05 < x < 0.25. It was also found that the highest conductivity is observed for x = 0.15. Finally, the thermal expansion of BaCe1−xSmxO3−δ (x = 0–0.2) is studied and the thermal expansion coefficients for the high temperature region are calculated.