Microheterogeneity and relaxation in 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 relaxor single crystals

Micro-Brillouin scattering has been applied to the observation of the microheterogeneity and the fast relaxation of 0.65 Pb(Mg1/3Nb2/3)O-3-0.35PbTiO(3) single crystals in various microareas with the size of 1-2 mu m. Cubic-tetragonal at TC-T and tetragonal-rhombohedral around TT-R transitions show different types of acoustic anomalies. It was found that local symmetry varies from one microarea to others below TC-T. Intense quasielastic scattering was observed below 250 degrees C; it is correlated with thermally activated fast relaxations of polar microregions. The results show that microheterogeneity and related dynamics of polar microregions are origins of relaxor phase transitions and are responsible for macroscopic properties like hypersonic damping. (C) 2000 American Institute of Physics. [S0003- 6951(00)00835-4].