Conductivity investigations of layered Mn<inf>2</inf>P<inf>2</inf>S<inf>6</inf> and Cu<inf>0.52</inf>Mn<inf>1.74</inf>P<inf>2</inf>S<inf>6</inf> crystals

Abstract

The dielectric properties of Mn ₂ P ₂ S ₆ and Cu _0.52 Mn _1.74 P ₂ S ₆ 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 (Mn ₂ P ₂ S ₆ ) and E _A /k= 0.81 eV (Cu _0.52 Mn _1.74 P ₂ S ₆ ). A suggestion is given that the electric conductivity in these crystals can be interpreted by electronic mechanism.