Thermal Hysteresis Accompanying Incommensurate-Commensurate Phase Transition in Mixed Crystals (K1-xCsx)2ZnCl4

The mixed crystal (K_1-xCs_x)₂ZnCl₄ with x = 0, 0.001, 0.01, 0.1, and 0.2 with optical quality has been grown by the Czochralski method. Using the Atomic Absorption Spectroscopy (AAS) and Energy Dispersive Spectroscopy (EDS), we determined the amount of Cs ion included in the mixed crystal. By using of DTA and DSC, we observed the change of T_c and T_i. The thermal hysteresis in the dielectric constants show strong dependence on the thermal process and on the amount of impurity which are explained by the influence of the thermal process and impurity, respectively on the creation, annihilation, and growth of discommensuration (DC).