Critical behaviour of the order parameters at the SmC* to SmA phase transition in a ferroelectric liquid crystal mixture

Abstract

Critical behaviour of the order parameters has been investigated in the ferroelectric liquid crystal mixture ZLI‐3654 in a 7.5 µm thick planar cell. The temperature dependence of the primary (tilt angle) and secondary (spontaneous polarisation) order parameters is considered. The critical exponent (β) has been evaluated from the fitting of the temperature dependence of the experimental data for both tilt angle and spontaneous polarisation. Experimental results are compared with the predictions of the de Gennes and Landau models.

Keywords:

• order parameter
• critical exponent
• ferroelectric liquid crystal mixture
• tilt angle
• spontaneous polarisation

Acknowledgements

The author wishes to thank E. Merck, Darmstadt, for providing the FLC sample. I sincerely thank the referee for his valuable advice and comments. The author is grateful to Prof. (Dr.) I. K. Bhat, Director, National Institute of Technology, Hamirpur for encouraging the research activities in the Institute.