Fast polarization mechanisms in the uniaxial tungsten-bronze relaxor strontium barium niobate SBN-81

0484342 - FZÚ 2018 RIV GB eng J - Článek v odborném periodiku
Buixaderas, Elena - Kadlec, Christelle - Kempa, Martin - Bovtun, Viktor - Savinov, Maxim - Bednyakov, Petr - Hlinka, Jiří - Dec, J.
Fast polarization mechanisms in the uniaxial tungsten-bronze relaxor strontium barium niobate SBN-81.
Scientific Reports. Roč. 7, Dec (2017), s. 1-11, č. článku 18034. ISSN 2045-2322. E-ISSN 2045-2322
Grant CEP: GA ČR GA16-09142S; GA MŠMT(CZ) LD15014
Institucionální podpora: RVO:68378271
Klíčová slova: relaxor * tungsten-bronzes * dielectric response * phonons * broad-band spectroscopy
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 4.122, rok: 2017

The high-frequency dielectric response of the uniaxial strontium barium niobate crystals with 81% of Sr has been studied from 1 kHz to 30 THz along the polar c axis by means of several techniques (far infrared, time domain terahertz, high-frequency and low-frequency dielectric spectroscopies) in a wide temperature interval 20-600 K. Relaxor properties were observed in the complex dielectric response and four main excitations were ascertained below the phonon frequencies. These fast polarization mechanisms take place at THz, GHz and MHz ranges and show different temperature evolution. The central mode excitation in the THz range, related to anharmonic dynamics of cations, slightly softens from high temperatures and then hardens below T similar to 400 K. Below the phase transition (at T similar to 330 K) an additional microwave excitation appears near 10 GHz related to micro domain wall oscillations. The strongest relaxation appears in the GHz range and slows down on cooling according to the Arrhenius law.
Trvalý link: http://hdl.handle.net/11104/0279495