Electrical properties of K₂ZnCl₄ crystals pure and doped with Co²⁺ ions between 300 and 500 K

Physics Department, Faculty of Science, Assiut University Assiut, Egypt

Corresponding author: abulfadl@aun.eun.eg

Received: 25 June 1998
Revised: 22 March 1999
Accepted: 22 March 1999
Published online: 15 June 1999

Abstract

The dielectric constant ε and the electrical conductivity σ were measured of crystalline plates cut perpendicular to the a-, b-, and c-axes from K₂ZnCl₄ (KZC) crystals, pure and doped with Co²⁺ ions, in the temperature range from 300 to 500 K. A pronounced broad peaks exists at the commensurate-incommensurate phase transition temperature (T_c1). A thermal hysteresis of about 10 K is observed for the transition during heating and cooling processes. The J-E characteristics along the crystallographic axes were measured below and above T_c1. Conductivity anomalies were observed at T_c1. The results of electrical conductivity temperature measurements were analyzed and the activation energies of conduction at different temperature regions have been evaluated. The mechanism of the electrical conduction of the various phases and the anomaly at the transition point was discussed.