Conductivity investigations of layered Mn2P2S6 and Cu0.52Mn1.74P2S6 crystals

Abstract

The dielectric properties of Mn₂P₂S₆ and Cu_0.52Mn_1.74P₂S₆ crystals were investigated in broad frequency (20 Hz-1 MHz) and temperature range (100 K-430 K). No anomaly in temperature dependence of complex dielectric permittivity indicating the polar phase transition can be detected in measured temperature range. The dielectric properties of presented crystals are mainly caused by high conductivity. The frequency spectra of conductivity obey the Almond-West power law. The activation energy of conductivity was found to be E_A/k= 0.82 eV (Mn₂P₂S₆) and E_A/k= 0.81 eV (Cu_0.52Mn_1.74P₂S₆). A suggestion is given that the electric conductivity in these crystals can be interpreted by electronic mechanism.