Raman shift of rare earth cobalt oxides

RCoO₃(R=La, Ce, Pr, Nd, Sm, Eu, Gd and Dy) perovskites prepared using the solid-state reaction method were examined by Raman spectroscopy. The Raman active Phonons in the RCoO3 perovskites crystallized in cubic symmetry for RCoO₃ (R=La, Ce, Pr and Nd) and orthorhombic symmetry for RCoO₃ (R=Sm, Eu, Gd, and Dy) were reported. The Raman spectra of RCoO₃ perovskites were strongly dependent on the ionic radius of the rare earth elements, and the frequency shift of the most intense modes of the orthorhombic samples were correlated with some structural parameters such as Co-O bond distances, ionic radius of the rare earth elements and John-Teller distortion. It is clear that Raman spectroscopy has the advantage of being very sensitive to structure distortion and oxygen motion.