J. Phys. II France 1 (1991) 797-803
Dielectric method for determining the electrical critical field in ferroelectric liquid crystalsA. Levstik1, Z. Kutnjak1, B. Zeks1, S. Dumrongrattana2 and C. C. Huang2
1 J. Stefan Institute, University of Ljubljana, 61111 Ljubljana, Jamova 39, Yugoslavia
2 School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 U.S.A.
(Received 14 January 1991, accepted 27 March 1991)
Both the electrical field and the dielectric constant ( ) associated with the Goldstone mode in the ferroelectric liquid crystals are related to the helical pitch. A direct relation between these two physical quantities is established. We have calculated the electrical critical field for both DOBAMBC and DOBA-1-MPC compound from the measured temperature variation of and polarization without any adjustable parameter. Just below the transition temperature region, the results obtained agree qualitatively with the experimental data. Away from the transition temperature, there exist systematic deviations.
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