Acoustic phonons in unfilled tetragonal tungsten-bronze crystals

0494887 - FZÚ 2019 RIV GB eng J - Journal Article
Buixaderas, Elena - Bérešová, Pavla - Ondrejkovič, Petr - Vaněk, Přemysl - Savinov, Maxim - Bednyakov, Petr - Dec, J. - Mareš, David - Ševčík, Martin - Landa, Michal
Acoustic phonons in unfilled tetragonal tungsten-bronze crystals.
Phase Transitions. Roč. 91, č. 9-10 (2018), s. 976-983. ISSN 0141-1594. E-ISSN 1029-0338
R&D Projects: GA ČR GA16-09142S
Institutional support: RVO:68378271 ; RVO:61388998
Keywords : phonons * tetragonal tungsten-bronzes
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.026, year: 2018

We have studied several unfilled tetragonal tungsten-bronze crystals (SBN-35, CBN-28, CBN-30, CBN-32) by differential scanning calorimetry, Brillouin spectroscopy and piezoresponse-force microscopy. The Brillouin backscattering configuration in the c-plates revealed the longitudinal acoustic phonon, which has a frequency near 50 GHz and displays softening when approaching the phase transition in all crystals. The ferroelectric domain structure and the domain size are dependent on the Sr/Ba or Ca/Ba ratios, and on the occupation rate in the channels as shown by the piezoresponse-force microscopy images. A splitting of the longitudinal acoustic phonon was found in SBN-35 in the multidomain sample, but poling of the crystal removed this splitting and just left the phonon with higher frequency.

Permanent Link: http://hdl.handle.net/11104/0287935