Dynamics of Central Peaks in the Brillouin Scattering Spectra of Relaxor Ferroelectrics
High-resolution Brillouin scattering technique was applied to study the dynamics of central peaks (CPs) in two relaxor ferroelectric systems, PLZT-x/65/35 ceramics and PMN-33%PT  single crystals, respectively. It was found that CPs appear very close to an intermediate temperature, Td, for both type of specimens. The temperature dependence of CPs was attributed to the appearance and subsequent growth of polar nanoregions (PNRs) intrinsic to relaxor materials.
Tadashi Takenaka, Hajime Haneda, Kazumi Kato, Masasuke Takata and Kazuo Shinozaki
G. Shabbir and S. Kojima, "Dynamics of Central Peaks in the Brillouin Scattering Spectra of Relaxor Ferroelectrics", Key Engineering Materials, Vols. 421-422, pp. 403-406, 2010