Phase transformations in barium-strontium niobate SBN-50 in the temperature range from 80 K to 700 K according to Raman spectroscopy data

The lattice dynamics of the Sr 0.5 Ba Nb 2 O 6 (SBN-50) ceramic was studied using Raman spectroscopy in temperature range 80-700 K with a step 10 K. analysis spectra ν=50-1000 cm -1 revealed features dependence behavior optical modes frequencies associated displacement Ba, and atoms from their average positions crystal lattice, which is macroscopic phase transition paraelectric to ferroelectric vicinity 390 It shown that anomalies at T~565 on dependences frequency line half-width corresponding oscillations NbO octahedron can be caused by presence polar nanoregions SBN-50. When sample cooled 80 K, recorded spectra, indicating occurrence structural 190 reasons for patterns are discussed. Keywords: ferroelectric, scattering, SBN, tetragonal tungsten bronze.