Broadband dielectric investigations of indium rich CuInP2S6layered crystals

Abstract

Results on dielectric properties of layered indium rich CuIn 1+δ P 2 S 6 crystals are presented. At low frequencies and high temperatures, the dielectric spectra are strongly influenced by the high ionic conductivity with the activation energy corresponding to 6815 K (0.587 eV). The high-frequency part of the dielectric spectra is determined by the relaxational soft mode. The critical slowing down and Debye-type dispersion show an order―disorder type of the ferrielectric phase transition at 330 K, which is substantially higher than for pure CuInP 2 S 6 . The high ferrielectric phase transition temperature suggests an idea that a frustrated ordering should appears in indium sublattice at low temperatures. Indeed, at low temperatures the complex dielectric permittivity exhibits behaviour typical for dipolar glasses.