Temperature study of (SrAl 0.5Ta 0.5O 3) 1− x− y:(LaAlO 3) x:(CaAl 0.5Ta 0.5O 3) y mixed perovskite crystals by Raman spectroscopy

Abstract

Temperature Raman scattering study were carried out for three component SAT 1− x− y :LA x :CAT y crystals with two different compositions. The low and high temperature investigations have been performed for SAT 0.5:LA 0.125:CAT 0.375 and SAT 0.24:LA 0.06:CAT 0.7 crystals in the spectral range 80–1000 cm −1. The Raman spectra obtained at room temperature for both crystals are different in the range of external F 2g(1) and internal bending F 2g(2) vibrational modes. During temperature study of SAT 0.5:LA 0.125:CAT 0.375 and SAT 0.24:LA 0.06:CAT 0.7 crystals, double and triple structure of F 2g(1) mode has been observed in the whole temperature range. Double and triple structure of internal F 2g(2) mode was observed for SAT 0.5:LA 0.125:CAT 0.375 and SAT 0.24:LA 0.06:CAT 0.7 crystals, respectively. However, one mode character of F 2g(2) mode was stated for SAT 0.5:LA 0.125:CAT 0.375 crystal at 630 K. A monotonous temperature changes in bands position for investigated crystals confirm both, stable character of static distortions and luck of any structural phase transition in these crystals in temperature range studied.