Acoustic phonon dynamics of Pb(Sc1/2Ta1/2)O3 ceramics studied by Brillouin scattering spectroscopy. (13th June 2019)

• Record Type: Journal Article
• Authors: Aso, Taro; Fujii, Yasuhiro; Koreeda, Akitoshi; Oh, Soo Han; Lee, Jeong Woo; Ko, Jae-Hyeon; Hong, Chang-Hyo; Jo, Wook
• Is Part Of: Japanese journal of applied physics. Volume 58:Number SG(2019)
• Publication Date: 2019-06-13
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/1347-4065/ab0bae
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: Brillouin spectra of highly-ordered Pb(Sc1/2 Ta1/2 )O3 (PST-O) and highly-disordered PST (PST-D) were measured over a wide temperature range. The frequency of the longitudinal acoustic (LA) phonon mode of PST-O showed a sharp anomaly corresponding to the sharp maxima of the dielectric permittivity, whereas that of PST-D exhibits a broad anomaly. The remarkable softening of LA phonon was observed below T * = 500 K, which indicates the occurrence of a piezoelectric coupling and/or electrostrictive coupling due to the appearance of non-centrosymmetric polar nanoregions below T *. The relaxation time of the LA phonon of PST-O shows a critical slowing down for order-disorder phase transition, while that of PST-D exhibits a stretched slowing down due to random electric fields related to B -site randomness.