Raman scattering and infrared spectroscopy of chemically substituted Sr(2)LnTaO(6) (Ln = Lanthanides, Y, and In) double perovskites

Abstract

Sr(2)LnTaO(6) (Ln = lanthanides, Y, and In) ceramics were prepared by a solid-state route, and their vibrational phonon modes were investigated using Raman and infrared (IR) spectroscopic techniques. Lorentzian lines were used to fit the Raman spectra, which showed 24 bands in perfect agreement with theoretical calculations. The IR spectra were fitted with a four-parameter semiquantum model, and the results showed 17 bands for the materials. The position and width of the phonon modes were determined and correlated to the ionic radii for the different atoms substituted in the B'-site. It was verified that all materials belong to the monoclinic P2(1)/n (C-2h(5)) structure.