High temperature Raman scattering study of ferroelastic lead phosphate single crystal

Abstract In this study, we have carried out the Raman scattering measurement on the pure ferroelastic Pb3(PO4)2 single crystal at the temperature from the room temperature up to 300 The lowest-frequency mode at 41 cm−1 at ambient temperature observed in vertical polarization/perpendicular-polarized (VH) scattering geometry shows slight softening up to the ferroelastic Curie temperature, Tc  = 182 and disappeared above this temperature, while in parallel polarization (VV) geometry, this lowest mode did not fully disappear above 182 The modes at 140 cm−1, 159 cm−1, and 184 cm−1 are merged into one broad peak above 182