- 著者
- Sivasubramanian V. Tsukada S. Kojima S.
- 出版者
- American Institute of Physics
- 雑誌
- Journal of applied physics (ISSN:00218979)
- 巻号頁・発行日
- vol.105, no.1, pp.014108, 2009
- 被引用文献数
- 9 4
The temperature dependences of acoustic phonon mode and the central peak have been investigated in Pb[(In1/2Nb1/2)0.65Ti0.35]O3 single crystal by Brillouin scattering. Longitudinal acoustic phonon begins to show marked softening below the Burns temperature TB~700 K. The longitudinal acoustic phonon mode exhibits clear anomalies at the cubic-tetragonal phase transition temperature of 540 K and at the tetragonal-rhombohedral one of 460 K. Below 600 K, the relaxation time calculated from the phonon mode agrees well with that of the broad central peak, suggesting a coupling between the local polarization and strain fluctuations of polar nanoregions. This temperature has been identified as another characteristic temperature T* besides TB, where the formation of long-lived polar nanoregions accompanied by the local strain fields governs the relaxation dynamics.
- 著者
- Sivasubramanian V. Kojima S.
- 出版者
- American Physical Society
- 雑誌
- Physical review B (ISSN:10980121)
- 巻号頁・発行日
- vol.85, no.5, pp.054104, 2012-02
- 被引用文献数
- 20 7
Brillouin spectra measurements have been carried out from 800 to 100 K for Pb(Sc1/2Ta1/2)O3 in back-scattering geometry. The frequency of the longitudinal acoustic (LA) phonon begins to show marked softening followed by an increase in its width below the intermediate temperature T* = 450 K. The gradual increase in the width of the LA phonon below T* is attributed to the electrostrictive coupling between the local polarization and strain. The frequency of the LA phonon mode exhibits anomalous behavior around 295 K, the phase transition temperature. The width of the LA phonon exhibits a sharp Landau-Khalatnikov-like maximum at 295 K. A central peak begins to appear around T* and exhibits critical slowing down upon further cooling. The relaxation times calculated for the LA phonon and central peak indicate the order-disorder nature of the phase transition.