Abstract :
We have investigated the behavior of the Li1.43Cs0.57SO4 single-crystal Raman spectra and dielectric permittivity as a function of temperature. It was observed that the crystal, which is an occupationally disordered system, with orthorhombic C2v2 structure at room temperature, undergoes a phase transition at 230 K. In the new phase the SO4 tetrahedra remain in two non-equivalent sites and there is no evidence of the doubling of the unit cell.
