Dielectric properties of four room temperature ferroelectric and antiferroelectric multi-component liquid crystalline mixtures

ABSTRACT

Dielectric properties of four recently formulated room temperature multi-component liquid crystalline mixtures with paraelectric (SmA*), ferroelectric (SmC*) and antiferroelectric (SmC*_A) phases have been studied as a function of temperature and frequency. Under planer anchoring condition, dielectric spectroscopy revealed all the characteristic modes: low frequency P_L and high frequency P_H mode in SmC*_A phase, Goldstone mode (GM) in SmC* phase and soft mode (SM) in SmA* phase. Dielectric behaviour has also been studied under the application of DC bias electric field. With bias electric field, we have been able to study the soft mode dielectric behaviour in the SmC* phase. An unknown high frequency mode (X-mode) with and without bias is also observed in SmC* phase. Dielectric results are explained in the light of generalised Landau theory. The mixtures show very high soft mode electroclinic coefficient in the SmA* phase in addition to fast switching in SmC*_A and SmC* phases [30].

GRAPHICAL ABSTRACT

KEYWORDS:

• Room temperature AFLC-FLC mixture
• dielectric spectroscopy
• P_L mode
• P_H mode
• Goldstone mode
• soft mode
• Landau theory
• DC bias field

Acknowledgements

We are grateful to Professor Roman Dabrowski, MUT, Poland, for supplying the compounds.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thankfully acknowledge the financial support under Board of Research in Nuclear Sciences project [2010/37P/44/BRNS/1441].