Dielectric characteristics and phase transitions in Tl(InS2) 1 − x (FeSe2) x solid solutions

This paper reports on a study of the electrical conductivity and permittivity of Tl(InS_{2) 1−x} (FeSe_{2) x} crystals as functions of composition and temperature. It has been found that the permittivity decreases in magnitude, while the electrical conductivity increases with increasing x. Crystals Tl(InS_{2) 1−x} (FeSe_{2) x} have been observed to undergo a sequence of phase transitions characteristic of TlInS₂, which manifests itself in formation of anomalies in the σ = f(T) and ɛ = f(T) temperature dependences. It has been shown that as x increases, the phase transition temperatures decrease, while the temperature region within which the incommensurate phase persists broadens slightly.