Structure of the OH− stretching vibrational band in SrxBa1−xNb2O6

Abstract

The stretching mode of the hydroxyl ions in SrxBa1−xNb2O6 crystals with x=0.38 to 0.79 has been measured by the Fourier transform infrared spectroscopy technique. The main absorption band at about 3493 cm−1 is accompanied by a shoulder on the low energy side. The shape of the shoulder depends strongly on the Sr/Ba ratio of the crystal which allows a rough estimation of the composition. The main absorption band including the shoulder has been decomposed using Lorentzian and Gaussian curves and the parameters of three components have been determined. The components are attributed to OH− transitions in different cation environments strongly depending on the crystal composition. The temperature dependence of the OH− absorption band is approximately linear in the 20–200 °C range and does not show any peculiarities at the phase transition temperature.