Phase transition and anisotropic conductivity in guanidine zinc sulfate crystals

The guanidine zinc sulfate [C(NH 2) 3] 2Zn(SO 4) 2 – abbreviated as GZS – crystal was grown and characterized by the calorimetric and dielectric investigations. Basing on the specific heat measurements the second order structural phase transition at temperature of about 178 K was found. The anisotropic ionic conductivity of GZS was observed in the complex dielectric measurements performed in wide temperature and frequency ranges: 140–320 K and 10 0–10 6 Hz, respectively. The activation energy of the conduction process measured along [110] direction varies from 0.43 eV in low temperature to 0.28 eV in high temperature phase. The activation energy in the [001] direction in the high temperature phase equals to 0.43 eV. The low frequency dielectric relaxation process of activation type in GZS crystals was found. ► Guanidine zinc sulfate [C(NH 2) 3] 2Zn(SO 4) 2 crystal grown from water solution. ► Second order structural phase transition at temperature 178 K determined by calorimetric method. ► Low freqency dielectric relaxation. ► Activation energy of the anisotropic ionic conductivity changes at phase transition temperature.