Ultrasonic spectra of the (AgI)x(AgPO3)1−x systems in the temperature range below Tg

An ultrasonic study (15–65 MHz) of the loss characteristic in superionic glasses (AgI)x(AgPO3)1−x was carried out in the 1–350 K temperature range. The loss behaviour is characterized at high temperatures by a broad peak due to the thermally activated relaxation of Ag+ ions, which are weakly bonded and mobile in the glassy network. The low temperature spectrum region can also be characterized by thermal relaxation processes, however with activation energies which are lower than those related to the Ag+ diffusion. The whole spectrum was fitted by two Gaussian-like distributions of relaxation times and such an analysis permits us to obtain some parameters connected with the microscopic structure.