LIQUID-LIKE MODEL FOR THE ULTRASONIC-ATTENUATION IN SUPERIONIC CONDUCTORS - APPLICATION TO ALPHA-AG2TE

Based on the assumption that mechanisms of energy dissipation in superionic conductors and in liquids are similar in a microscopic scale, a new model for the ultrasonic attenuation in superionic conductors has been presented. The theoretical results of Rice and Allnatt for the dense fluids are used to express the viscosity and thermal conductivity in superionic conductors. The cage sublattice is considered by in-troducing a heavy ion mass, which conveniently characterizes immobile lattice ions when the system is observed from the viewpoint of the liquid theory. The model has been applied to superionic conductor α-Ag2Te to obtain the coefficients of viscosity and of ultrasonic attenuation, and the results showed that the model was sufficiently promising. According to this model, the main mechanism for the ultrasonic attenuation is the hard core collisions between the mobile ions and the surrounding lattice ions. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.