Mechanical relaxation in a ternary silver borate below the glass transition temperature and corresponding features of the electrical response

Mechanical spectroscopy allows the investigation of the relaxation processes, associated with the hopping of mobile ions occurring in ionic glasses well below their glass transition temperature. In the present work we study the properties of the secondary mechanical relaxation in the fast ion conducting glass (AgI)x[(Ag2O)·n(B2O3)]1−x with n = 2 and x = 0.6 as revealed by ultrasonic measurements at MHz frequencies in a wide temperature range. We analyze the results in comparison with the features observed performing broadband dielectric measurements on the same materials. The electric response is discussed in terms of complex electric modulus. This formalism allows us to point out interesting analogies with the ultrasonic results.