Electrical and thermal studies in the commensurate incommensurate phase region of (NH4)2ZnCl4 single crystal

DC electrical conductivity for a virgin and poled annealed (NH4)(2)ZnCl4 b-axis single crystal shows a defect controlled property. A Schottky mechanism is a probable mechanism of conduction in regions of strong structural transitions. The rise of conductivity in the incommensurate and paraelectric phases is linked to an increase in discommensurations density. The activation energies (DeltaE) in the three phases region were calculated. DTA measurements shows that the crystal is stable up to 200 degreesC and the phase transition temperatures were observed at 42, 94.8 and 137 degreesC. The effective activation energy (E-e) was obtained using Kissinger and Mahadevan equations. It was found to be equal to 0.49 eV. This correlates with the value obtained through DC conductivity. (C) 2002 Published by Elsevier Science Ltd.