ac conductivity and dielectric relaxation studies in $AgI$-based fast ion conducting glasses

ac conductivity and dielectric relaxation in $AgI$-based fast ion conducting glasses have been examined in four systems: $AgI-Ag_2MoO_4$, $AgI-Ag_3AsO_4$, $AgI-AgPO_3$ and $AgI-Ag_20-V_2O_5$. Dielectric relaxation is examined using modulus formalism. Suitability of stretched exponential relaxation function has been investigated. Inverse relation has been found to exist between the stretching exponent and the structural unpinning number which characterizes fast ion conduction. Physical origin of correlated states, relevance of cluster-tissue model of glasses and the role of structural unpinning concept have been examined in the light of dielectric behavior of $AgI$-based glassy fast ion conductors