Brillouin spectra of the solid electrolyte Li2SO4

Abstract
Brillouin spectra of single crystals of the solid electrolyte Li2SO4 were obtained for various crystal orientations in the temperature range 899–1120 K. The spectra contained one longitudinal component and at least one and sometimes both transverse components. The frequency shifts varied between 14.5 and 17.4 GHz for the longitudinal and between 4.1 and 9.0 GHz for the transverse component, the shift being strongly dependent on crystal orientation. The observed frequency shifts correspond to values of the elastic constants typical for plastic materials.