Soft Mode Dielectric Relaxation Under the Influence of Bias Electric Field of a Ferroelectric Liquid Crystal Mixture

Abstract

Temperature dependent soft mode part of the complex dielectric constant has been measured as a function of bias electric field both in the smectic C* and smectic A* phases for a ferroelectrc liquid crystal (FLC) mixture. From the experimental data, soft mode relaxation frequency and dielectric strength have been determined both in smectic C* and smectic A* phases. In smectic A* phase, relaxation frequency and inverse of dielectric stmngth of the FLC mixture does not follow the Curie-Weiss law. The critical exponent for the studied FLC mixture is 1.43. Dielectric results shows a dependence of soft mode dielectric strength and relaxation frequency with bias field near the tmudion temperature in smectic A* phase to an extent of 1°C above the transition tanperature and above 1°C bias field does not have any effect on relaxation frequency and dielectric strength It is observed that relexation frequency increases with increasing bias field while the compounding dielectric strength decreases.