Studies on the dielectric properties and structural phase transition of K2SO4 crystal

Electrical complex impedance measurements were carried out on K2SO4 single crystal. The temperature and frequency dependence of electrical conductivity, dielectric constant, and the electrical modulus were determined. The increase in conductivity with rise in temperature showed the superionic nature of the sample in the high-temperature phase. The results also show that the temperature dependence of AC conductivity and conduction relaxation time approximately follows the Arrhenius relation. The activation energies and characteristic relaxation times were calculated. The AC conductivity as a function of frequency is well described by sigma(omega) = sigma(0) + A omega(s). Here sigma(0) is the DC conductivity, and s is the fitting parameter. Non-Debye dynamic conduction was observed in the sample crystal. The obtained values of s decrease with increasing temperature, from 1.27 to 0.61 and 0.43 to 0.28 in the room-temperature phase and in the high-temperature phase, respectively. This effect is attributed to the interaction of the mobile ions with the SO4 groups in the K2SO4 single crystal. (C) 2000 Elsevier Science Ltd. All rights reserved.