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Underdamped soft phonon in orthorhombic BaTiO3

1990; Elsevier BV; Volume: 76; Issue: 6 Linguagem: Inglês

10.1016/0038-1098(90)90623-j

1879-2766

K. Laabidi, M.D. Fontana, B. Jannot,

Photorefractive and Nonlinear Optics

Raman scattering measurements are reported in orthorhombic phase and through the orthorhombic-rhombohedral transition of BaTiO3. Spectra reveal the presence of an underdamped low frequency phonon which slightly softens with decreasing temperature and abruptly stiffens at the transition to the rhombohedral phase. Results are discussed in comparison with isomorphous KNbO3 and tetragonal BaTiO3 and are interpreted as due to a dominant displacive mechanism.