Phase transitions investigation by Raman spectroscopy in highly diluted KTN crystals

Single crystals of potassium tantalate niobate, KTa1−xNbxO3 (KTNx, x = 0.45, 0.50, and 0.55), were synthesized by the top-seeded solution growth method. The Raman scattering technique is used to investigate the sequence of phase transitions undergone by KTNx crystals. We discuss what features in the phonon spectrum are associated to each phase transition.

► The sequence of phase transitions of highly diluted KTNx single crystals was investigated by Raman scattering technique.
► The C–T and T–O phase transitions are straightforwardly observed and discussed.
► The O–R phase transition is characterized by changes in the slope (dν/dT) and of the intensity ratio of the modes appearing in the 500–600 cm−1 spectral region.