Superionic conductivity of (TlGaSe$_{2}$)$_{1-x}$(TlInS$_{2}$)$_{x}$ solid solutions

Samples of (TlGaSe$_{2}$)$_{1-x}$(TlInS$_{2}$)$_{x}$ solid solutions are synthesized. The frequency dependences (2 $\times$ 10$^1$–10$^6$ Hz) of components of the total complex impedance are studied by the impedance spectroscopy technique and relaxation processes are investigated depending on the composition of the (TlGaSe$_{2}$)$_{1-x}$(TlInS$_{2}$)$_{x}$ solid solution in the solubility region ($x$ = 0–0.4). Corresponding diagrams on the ($Z$"–$Z$') complex plane are analyzed using the equivalent substitutional circuit method. An anomaly in the temperature dependence of the electrical conductivity, which manifests itself in an abrupt increase in the conductivity, is found for the studied (TlGaSe$_{2}$)$_{1-x}$(TlInS$_{2}$)$_{x}$ solid solution at 400 K. This peculiarity is associated with the phase transition into the superionic state.