J. Phys. II France
Volume 1, Numéro 2, February 1991
Page(s) 171 - 180
DOI: 10.1051/jp2:1991153
J. Phys. II France 1 (1991) 171-180

Dielectric studies of Goldstone mode and soft mode in the vicinity of the A-C $^\star$ transition

S. M. Khened, S. Krishna Prasad, B. Shivkumar and B. K. Sadashiva

Raman Research Institute, Bangalore 560080, India

(Received 6 August 1990, accepted in final form 5 November 1990)

We report the results of dielectric studies on three ferroelectric liquid crystals exhibiting the A-C $^\star$ transition. Two relaxation modes viz., the soft mode and the Goldstone mode have been observed in the frequency domain covered. Careful measurements have allowed us to observe the soft mode relaxation in the C $^\star$ phase, even in the absence of a bias field, over a larger temperature range than in any previous study. The results are discussed in the light of the predictions of the generalised mean-field model.

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