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

Yurtseven H., Kilit E.

PHYSICS AND CHEMISTRY OF LIQUIDS, cilt.50, sa.3, ss.367-377, 2012 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 50 Konu: 3
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1080/00319104.2011.651209
  • Sayfa Sayıları: ss.367-377


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.