Phase transition in superionic AgΛ8HgSΛ2IΛ6

Electric acoustic properties and structural parameters of Ag8HgS2I6 crystals have been studied. The conducted investigations of temperature dependences of damping α and velocity of longitu idal supersound Vn have revealed that in the region of activation energy alteration temperature the maximum α and minimum V take place, that manifests itself both during sample temperature increase or decrease. It has been assumed on the basis of the obtained experimental data that a phase transition occurs in Ag8HgS2I6 compound in the vicinity of the temperature of 235 K, that may be conditioned by the change of population of allowed positions in a disordered cation sublattice