The alternating-current conductivity and dielectric relaxation properties of silver selenomolybdate glasses, yAgI–(1–y){MAg2O–F[0.4SeO3–0.6MoO3]} with various dopant salt concentrations (y = 20 to 80%) were investigated. The direct-current conductivity was found to increase by more than 2 orders of magnitude with increasing AgI concentration. The variation of conductivity with AgI concentration was rationalized by considering a so-called, mixed cluster tissue to amorphous AgI aggregate, model for glass structure. The presence of positional disorder of Ag+ ions in the AgI aggregate region was found to be responsible for the observed enhancement in ionic conduction and also to the variation of conductivity with AgI concentration. The alternating-current conductivity was frequency independent at low frequencies and follows an apparent power law, σ ωn at the high-frequency region. The observed dispersion in conductivity with frequency was attributed to the high probability for the correlated forward–backward hopping of mobile ions in the high-frequency region. The temperature dependence of alternating-current conductivity at fixed frequencies was analyzed by using a bi-exponential law with 2 distinct activation energies. The origin of the 2 activation energies observed in the alternating-current conductivity was explained in the light of the jump relaxation model. The electrical modulus which describes the dielectric relaxation behavior of the glasses was fitted to a stretched exponential, and it obeyed time-temperature superposition.

Conductivity Relaxation and Ion Transport Processes in Glassy Electrolytes. N.Baskaran: Journal of Applied Physics, 2002, 92[2], 825-33