Unit-cell symmetries and Raman spectra of calcium- and neodymium-doped barium cerate proton-conducting ceramic electrolytes

Abstract

Combined X-ray powder diffraction and Raman spectroscopic investigations of the systems BaCe_1–xCa_xO_3–x and BaCe_1–xNd_xO_3–α at ambient temperature are presented. X-Ray studies involving in-depth investigation of diffraction profiles show that the unit cell (a crystal average) is truly orthorhombic throughout the composition ranges of both systems. The Raman spectra for BaCe _1–xCa_xO_3–α are similar to that for BaCeO₃ itself, indicating little distortion of the structure when calcium is dopant. A feature at around 610 cm^–1 in the spectra for BaCe_1–xNd_xO_3–α and not evident in the spectra of Ca-doped samples, is associated with modes involving the rare-earth-metal dopant.