Critical behaviour of the dielectric constant for the smectic AC* transition under the electric field in ferroelectric liquid crystals


YURTSEVEN H. H. , Kilit E.

PHYSICS AND CHEMISTRY OF LIQUIDS, vol.50, no.3, pp.367-377, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 3
  • Publication Date: 2012
  • Doi Number: 10.1080/00319104.2011.651209
  • Title of Journal : PHYSICS AND CHEMISTRY OF LIQUIDS
  • Page Numbers: pp.367-377

Abstract

The temperature dependencies of the dielectric constant and the tilt angle (order parameter) are calculated under the electric field for the smectic A-smectic C* (AC*) transition in 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl (A7). The dielectric constant is fitted to the experimental data by using our mean field model with the biquadratic coupling between the spontaneous polarisation P and the tilt angle theta. Our results show that the mean field model with the P-2 theta(2) coupling describes satisfactorily the observed behaviour of the AC* transition in A7. It is indicated here that a first-order AC* transition occurring at low electric fields changes its character towards a second order as the electric field increases in A7.