Phase transition and anisotropic conductivity in guanidine zinc sulfate crystals

The guanidine zinc sulfate [C(NH2)3]2Zn(SO4)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 100–106 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.