Thakur, A. K. and Choudhary, A. and Kaur, S. and Bawa, S. S. and Biradar, A. M.
(2006)
A dielectric mode in electroclinic liquid crystals.
Journal of Applied Physics , 100 (3).
034104-1-034104-8.
ISSN 0021-8979
Abstract
The dielectric properties of electroclinic and ferroelectric liquid crystal materials have been investigated in the frequency range of 100 Hz - 10 MHz. A dielectric mode has been predicted in electroclinic liquid crystals near the transition temperature of Sm-C*-Sm-A phase. It has been observed that the investigated material has nonlayer shrinkage near the transition temperature of Sm-C*-Sm-A phase and shows anomalous behavior of dielectric spectra, tilt, and texture which is entirely different from the behavior of ferroelectric liquid crystals (FLCs). The dielectric relaxation frequency and tilt angle are almost constant with respect to temperature near the transition temperature under high bias field, which is characteristically different from FLCs. The high dielectric permittivity near T-c owing to the presence of mode contribution leads to the fact that there is an intralayer phason variation few degrees before transition. The mode has been named random mode due to its origin from randomization of tilt near T-c. Tilt randomization has been considered as an order parameter because in both the phases molecules are tilted but it is disordered in Sm-A phase making its intralayer polarization zero.
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