Dynamics of mesoscopic polarization in the uniaxial tetragonal tungsten bronze (Sr.sub.x./sub.Bai.sub.1-x./sub.)Nb.sub.2./sub.O.sub.6./sub.

0517757 - FZÚ 2020 RIV US eng J - Journal Article
Buixaderas, Elena - Kempa, Martin - Svirskas, Š. - Kadlec, Christelle - Bovtun, Viktor - Savinov, Maxim - Pasciak, Marek - Dec, J.
Dynamics of mesoscopic polarization in the uniaxial tetragonal tungsten bronze (Sr_xBai_1-x)Nb₂O₆.
Physical Review B. Roč. 100, č. 18 (2019), s. 1-11, č. článku 184113. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA ČR GA16-09142S; GA MŠMT(CZ) EF16_019/0000760
Grant - others:OP VVV - SOLID21(XE) CZ.02.1.01/0.0/0.0/16_019/0000760
Institutional support: RVO:68378271
Keywords : tetragonal tungsten-bronzes * polarization * dielectric response * relaxors
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.575, year: 2019
Method of publishing: Limited access
https://doi.org/10.1103/physrevb.100.184113

The high-frequency dielectric behaviour of uniaxial tungsten-bronze strontium barium niobate crystals with various Sr/Ba ratios, including both ferroelectric and relaxor compositions, have been studied in a broad frequency range (10^4 to 10^13 Hz) and temperature interval 100–500 K in order to thoroughly understand the evolution of the relaxation dynamics across the ferroelectric phase transition. The dielectric response along the polar axis consists of three relaxations corresponding to polarization mechanisms related to several correlation lengths of mesoscopic order. All of them show dissimilar behaviors with temperature, pointing out to their distinct nature. A temperature dependent central mode at THz frequencies and a relaxation above 10 GHz are accompanied by the slowing down of a relaxation in the MHz range. This response reveals the complex mechanism of the phase transition and supports the coexistence of displacive and order-disorder scenarios.

Permanent Link: http://hdl.handle.net/11104/0303041