Broadband Dielectric Spectroscopy of Ferroelectric Liquid Crystal

Different smectic-phase transition temperatures have been observed from the study of the temperature dependence of dielectric strength and relaxation frequency. The phase transition temperatures (crystalline to isotropic phases) have also been observed from the temperature-dependent symmetric and asymmetric shape parameters of the relaxation function and also the DC conductivity obtained from the fitting procedure. We have obtained the chiral smectic C–smectic X (SmC * –SmX) phase transition temperature very precisely from Arrhenius' plot of the relaxation frequency. In a planar-aligned cell, four relaxation processes have been observed in both the SmX and SmC * phases. The three symmetric modes are the Goldstone mode, domain mode, and molecular mode. The other asymmetric mode (X-mode) observed in the present measurement may be related to the interaction of dipoles of the ferroelectric liquid crystals being affected by the surface of the cell. In the SmA phase, we have observed two relaxation modes: the molecular mode (symmetric) and X-mode (asymmetric).