Raman Spectrum of BaTiO₃

Abstract

Seven Raman lines of the tetragonal BaTiO₃ single crystals, excited by the Hg–c line, have been observed at 359, 416, 502, 513, 736, 823 and 1181 cm⁻¹ from the c-line. The three lines of higher frequencies are interpreted to be corresponding to the lattice vibrations of higher mode. A possible explanation of the four lines of lower frequencies is presented as corresponding to the fundamental modes of vibration in tetragonal BaTiO₃. A possibility is pointed out that the “ferroelectric mode” splits into two species, of which frequencies are near 340 cm⁻¹ and near 34 cm⁻¹, respectively. The Raman line located at 359 cm⁻¹ is interpreted to be corresponding to the former species.