Refractive index of ferroelectric Pb2ScTaO6 single crystals around the phase transition

A modified prism method has been used for the Refractive Index (RI) determination of lead scandium tantalate Pb2ScTaO6 (PST) single crystals with perovskite structure. The crystals are obtained by the High Temperature Solution Growth (HTSG) method. The RI values of PST crystalline prism are measured with error of ±2×10−3 in the temperature range 0–40°C. A jump around 15°C is observed in the temperature dependence of RI, which is explained by the presence of the diffuse paraelectric (PE)–ferroelectric (FE) phase transition. Transmission spectra (TS) in the same temperature range are presented.