Raman spectroscopy of perovskite-type BaCexZr1-xO3 (0 ≤ x ≤ 1)

Polycrystalline samples of BaCexZr1-xO3 were prepared by solid state reaction. X-ray diffraction measurements show that all compounds are single-phase and XRD patterns can be indexed on the basis of the ideal perovskite structure. However, Raman data show that BaCexZr1-xO3 exhibits slight x-dependent distortions from the ideal perovskite structure. Indeed the evolution of Raman spectra of BaCexZr1-xO3, as x decreases at room temperature or as temperature increases for a given x value, is similar to the evolution of Raman spectra of BaCeO3 as temperature increases. These observations lead us to propose a phase diagram in the binary system BaCeO3-BaZrO3 based on the known structures of BaCeO3 (Pnma, Imma, R bar 3c, and Pm3m)