Temperature dependence Raman spectroscopic studies of Pb(Yb0.5Ta0.5)O3

The lead-based complex perovskite Pb(Yb0.5Ta0.5)O3, exhibiting long-range B-site cation ordering has been studied by Raman spectroscopy. The investigation has been performed as a function of temperature ranging from 250 K to a lower temperature 10 K in the spectral range 1020–20 cm−1. The spectra are analyzed through the characteristic parameters: peak position and line width of phonon modes. Significant decrease in the asymmetric phonon line broadening with noticeable shift of the peak positions and appearance of new modes in the Raman spectra at low temperature have been observed. The local distortion in the lattice has been enhanced substantially at low temperature. The splitting of the F2g modes suggests that the orthorhombic phase is stabilized at low temperature. The two F2g modes (60 and 518 cm−1) show soft mode behavior.