Thermodynamical, electrical and electro-optical studies of a room temperature tri-component antiferroelectric liquid crystalline material

Abstract

Thermodynamic and electric studies show the wide room temperature range antiferroelectric SmC*_a (91.1 to −20.0 ºC) phase in addition to narrow temperature range paraelectric SmA* (∼2.1 ºC) and ferroelectric SmC* (∼4.3 ºC) phases in thestudied antiferroelectric material. Frequency-dependent dielectric studies show five different relaxation modes appearing in SmA*, SmC* and SmC*_a phases under the planar anchoring condition of the molecules. The ferroelectric SmC* to paraelectric SmA* transition temperature has been found to be 97.3 ºC using Curie–Weiss law. The dielectric response of SmC*_a phase exhibits three relaxation modes in addition to Goldstone mode in SmC* phase and soft mode in SmA* phase. Polarizations, switching time and rotational viscosity have also been determined. Maximum value of polarization (P) is ∼300 nC/cm². Switching time is the order of few milliseconds.

Keywords:

• soft and Goldstone modes
• spontaneous polarization
• relaxation frequency
• dielectric strength

Acknowledgements

One of us, Avneesh Mishra, thanks DAE-BRNS especially for a Junior Research Fellowship under the project.

Additional information

Funding

We thank Department of Atomic Energy, Board of Research in Nuclear Sciences (DAE-BRNS) for financial assistance [grant number 2010/34/38/BRNS2038].