%0 Journal Article %T A central peak in light scattering from the relaxor-type ferroelectric Na 1/2Bi 1/2TiO 3 %+ Université d'Orléans (UO) %+ Centre National de la Recherche Scientifique (CNRS) %A Siny, I. G. %A Husson, E. %A Beny, J. M. %A Lushnikov, S. G. %A Rogacheva, E. A. %A Syrnikov, P. P. %< avec comité de lecture %@ 0921-4526 %J Physica B: Condensed Matter %I Elsevier %V 293 %P 382-389 %8 2001 %D 2001 %Z 2001PhyB..293..382S %R 10.1016/S0921-4526(00)00549-4 %Z Sciences of the Universe [physics]Journal articles %X A complex perovskite-type single crystal Na 1/2Bi 1/2TiO 3 (NBT) has been studied by Raman scattering. A broad central component has been revealed to analyze the temperature dependence of its intensity and width for the first time. The central component has features of a relaxation mode with the highest intensity in the intertransition region, so it arises from a critical light scattering on fluctuations of two coupled order parameters. The correlations between the central component behaviour, acoustic anomalies and dielectric response as well as their relation to a model with competing interactions are discussed. It is suggested that the broad central peak component in light scattering is characteristic of the relaxor-type ferroelectrics with a sequence of phase transformation irrespective of whether transitions are really observed as in NBT or whether transitions are frustrated under normal conditions as in PbMg 1/3Nb 2/3O 3 (PMN). %G English %L insu-03618069 %U https://insu.hal.science/insu-03618069 %~ INSU %~ CNRS %~ UNIV-ORLEANS