Akademik Veri Yönetim Sistemi
PHYSICS AND CHEMISTRY OF LIQUIDS, cilt.50, sa.3, ss.367-377, 2012 (SCI-Expanded)
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.