Relaxation phenomena of a highly tilted ferroelectric liquid crystalline material (S)-(+)-4′-(3-pentanoyloxy prop-1-oxy)biphenyl-4-yl-4-(1-methylheptyloxy)benzoates

Abstract

Titled ferroelectric liquid crystalline material (in short, 4H3R) exhibits cholestric (N*), ferroelectric (SmC*) and hexatic (SmB*) phases, when it is cooled from isotropic liquid phase to crystal phase. Dielectric studies have been carried out in the frequency range of 1 Hz to 35 MHz under planar anchoring conditions of the molecules. The soft mode relaxation due to the amplitude fluctuation of the polarisation vector has appeared in the N* phase, whose relaxation frequencies decrease but dielectric strength marginally increases (~0.30–0.54) with decrease in the temperature. The Goldstone relaxation mode has appeared in SmC* phase with a constant relaxation frequency. The relaxation frequency of hexatic SmB* phase follows Arrhenius behaviour. The conductivity of the material is also measured in all the exhibited phases.

Keywords:

• ferroelectric liquid crystal
• dielectric permittivity and loss
• soft and Goldstone modes
• conductivity

Additional information

Funding

The work was supported by Department of Atomic Energy, Board of Research in Nuclear Sciences (DAE-BRNS), India, for financial assistance under a research grant number 2010/34/38. Avneesh Mishra thanks DAE-BRNS especially for a Senior Research Fellowship.