Acoustic phonons in unfilled tetragonal tungsten-bronze crystals. (3rd October 2018)

• Record Type: Journal Article
• Authors: Buixaderas, E.; Bérešová, P.; Ondrejkovič, P.; Vaněk, P.; Savinov, M.; Bednyakov, P.; Dec, J.; Mareš, D.; Ševčík, M.; Landa, M.
• Is Part Of: Phase transitions. Volume 91:Number 9/10(2018)
• Page Start: 976
• Page End: 983
• Publication Date: 2018-10-03
• Subjects: Acoustic phonons -- tetragonal tungsten-bronzes -- piezoresponse-force microscopy -- ferroelectric domains; Phase transformations (Statistical physics) -- Periodicals; 530.47405
• DOI: 10.1080/01411594.2018.1499914
• Languages: English
• ISSNs: 0141-1594

Abstract

ABSTRACT: 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.