The Raman spectrum of pure and barium doped lead germanate

Abstract
Observations of the Raman spectra of Pb5-x Ba x Ge3O11 show that for 0<X ≤ 0.4 while there are small changes in relative intensities and increased broadening of all the modes, the frequencies and number of both the lattice and internal modes do not appear to be substantially altered in comparison to those of the pure material. The temperature dependence of the ferroelectric soft A-mode however is dramatically affected, even for small X and this is accompanied by a much reduced transition temperature.