Electrical conductivity and phase transition studies on K2SO4 crystals

Abstract The electrical conductivity measurements on single crystals of K 2 SO 4 have been carried out in the temperature range from 300 to 800°C. The bulk ionic conductivity along the three principal crystallographic axes has been determined by means of complex impedance formalism. The ionic conductivity in the low-temperature β phase follows closely the classical Arrhenius law up to around 540°C, which is some 50°C below the β → α transition temperature ( T c ). From 540°C, the slope of the conductivity curve increases up to T c and is attributed to the existence of a pretransitional region, in which significant rotational disorder of sulfate ions is present. The thermal hysteresis of theα ↔ β transition and the conductivity anisotropies are discussed. The dielectric properties and the conductivity relaxation studies by means of electric modulus formalism are also discussed.