Features of Raman spectra in barium titanate pressed powder

Raman spectra in barium titanate powder under non-hydrostatic pressures are presented. The relationship between the pressure (up to 11 GPa) and the shift and the width of E(TO)-phonon line has been established. It has been found that under the action of uniaxial pressure a new Raman peak arises in the vicinity of 100 cm⁻¹. It is shown that the Raman shift and width of both peaks increase depending on the applied pressure. These Raman lines broadening may be associated with an increase of the concentration of defect states in the volume of the sample. (paper)