0000000000177812
AUTHOR
K. Laabidi
showing 3 related works from this author
Underdamped soft phonon in orthorhombic BaTiO3
1990
Abstract 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.
Indications of Two Separate Relaxators in the Subphonon Region of Tetragonal BaTiO 3
1994
Significant discrepancies were generally reported in the dynamics of BaTiO3 between results deduced from various experimental techniques. Here dielectric and quasi-elastic light scattering measurements are investigated on high-quality BaTiO3 crystals. We show that two relaxators have to be introduced below the soft-phonon frequency. A complete dielectric dispersion in a very wide frequency range is thus achieved which consistently relies the high-frequency dielectric results and the Raman data. There is also a qualitative agreement between our two-relaxator model and the dynamics which were deduced some time ago from EPR experiments.
Existence of two time scales in the phase transitions of BaTiO3
1991
Abstract We report new Raman scattering measurements in the tetragonal phase of a single domain BaTiO3 crystal. Data reveal the occurence of a large quasi elastic scattering. The Raman profile is analysed in terms of coexisting soft phonon and Debye relaxation.