Dielectric Relaxation Near the Transition Temperature of Sm C*-Sm A Phase in Electroclinic Liquid Crystal

Abstract

The dielectric relaxation processes of electroclinic liquid crystal material have been investigated in a thin (2.5 w m) planarly well aligned cells in the frequency range of 50 Hz to 10 MHz. The behaviour of Goldstone and Soft mode which comes due to phase fluctuation and tilt fluctuation of the molecules has been studied at different temperatures and different bias fields in Sm C* and Sm A phases. It has been observed that Goldstone mode appears in Sm C* phase and soft mode in Sm A phase. However, near the transition temperature of Sm C*-Sm A, the dielectric permittivity due to Goldstone mode and soft mode could not be separated. It is concluded and discussed that there is no sharp transition temperature of Sm C*-Sm A phase in electroclinic liquid crystal, due to the continuous decrease in the dielectric permittivity and increase in the relaxation frequency near the transition of Sm C* to Sm A phase.