a UFR Faculté des Sciences, Laboratoire d'Etudes Physiques des Matériaux, BP 6759, Université d'Orléans, 45067, Orléans Cedex 2, France
b Centre de Recherches sur la Physique des Hautes Températures, CNRS, 45071, Orléans, France
Abstract:
A Brillouin investigation in CsHSeO4 has been performed over the temperature range 20–165 °C which includes two phase transitions, in particular the transition to the superionic phase near Ts = 129 °C. We observed strong discontinuities for elastic constants C11, C22 and C33 at Ts and a broadening of the Brillouin lines above Ts. The results are discussed on the basis of a linear coupling between strains and mobile protons.