Correspondence between electro-optic properties and the raman scattering in oxydic perovskites

Abstract

The physical origin of the large electro-optical properties exhibited by the oxygen-octahedra ferroelectrics is discussed in relation with the dynamical properties, as determined by Raman and infrared spectroscopy. The largest electro-optic coefficient is shown to correspond to the symmetry of the most intense Raman peak. The soft polar optical phonon is pointed out to be dominant in the ionic displacements contribution of the electro-optic coefficient. The role of the oxygen polarizability in the soft mode mechanism, the Raman intensity as well as in the electro-optic effect is emphasized for the ABO₃ materials.