Dielectric relaxations in a room temperature ferroelectric liquid crystalmixture

Abstract

Dielectric properties of ferroelectric liquid crystalline mixture FLC-6980 and its anthraquinone dye (2% wt/wt) doped sample have been studied in SmC* and SmA phases in the frequency range from 100 Hz to 1 MHz in planar and homeotropic aligned cells. We observed the molecular relaxation mode in the homeotropically aligned cell at 33 °C at a frequency of 36 kHz in the SmC* phase. In the planar cells, goldstone and a new relaxation mode have been observed. A soft mode appeared in the vicinity of the SmC*-SmA transition. The dielectric increment, distribution parameter and relaxation frequency of these modes have been evaluated at different temperatures and bias voltages. Our results are in agreement with the extended Landau model.