Raman and XPS Studies for Ba_1-xEu_xTiO₃ Synthesized by High Pressure and Temperature

Abstract

A series of perovskite oxides of Ba_1-xEu_xTiO₃ (x=0. 0, 0. 1, 0. 2, 0. 3, 0. 4) were synthesized under 4. 0GPa and at 1090°C. The samples with x=0. 0 and 0. 1 are mixed phase of cubic and tetragonal, whereas those with x=0. 2, 0. 3 and 0. 4 are single phases. The structural transformation from tetragonal to cubic was observed at x=0. 3. Raman spectra of BaTiO₃ exhibited four bands which is consistent with tetragonal structure. For x=0. 2 and 0. 4 samples, only one band at low frequency was observed. XPS and EPR measurements indicated that Eu and Ti ions were in mixed valence.