Calculation of the Dielectric Constant as a Function of Temperature Near the Smectic AC* Phase Transition in Ferroelectric Liquid Crystals

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

“…From the temperature dependence of the spontaneous polarisation at constant electric fields, the dielectric susceptibility P was evaluated as a function of temperature for the AC* transition in ferroelectric liquid crystals [17]. In this study, we evaluate the temperature dependence of the inverse dielectric constant À1 for constant electric fields, according to Equation (7), where the transition temperature T o depends on the electric field.…”

“…in our earlier study [17]. Using the free energy in the same form as Equation (1) with the additional electric-field energy term EP, the dielectric susceptibility was obtained as [17]…”

“…Using the experimental data [26], we have calculated the temperature dependence of the spontaneous polarisation for A7 [3] and the concentration dependence of a binary mixture of A7 þ C7 [20] in our earlier studies. Recently, we have calculated the temperature dependence of the polarisation and tilt angle [16] and dielectric constant [17] at various electric fields in A7. Also, close to the smectic A-isotropic liquid transition (AI), we have analysed the experimental " ?…”

“…These bilinear coupling P [10,11] and the biquadratic coupling P 2 2 [12][13][14][15] between the spontaneous polarisation P and the tilt angle have been considered in the mean field models for various liquid crystalline systems. Regarding the biquadratic P 2 2 coupling, we have studied the mean field models for the AC* transition in A7 [3,16,17], in binary mixtures [18][19][20][21][22] and also for the C* phase of SCE9 and SCE10 [23].…”

Analysis of the Dielectric Constant as a Function of Temperature at Constant Electric Fields for the Smectic A-Smectic G Transition in A6

“…A bilinear coupling between the spontaneous polarization and the tilt angle (Pθ coupling) [5,7] and the biquadratic coupling (P 2 θ 2 coupling) [3,4] have been considered in the mean field models mainly for the smectic AC (or AC * ) transitions. We have also studied the AC or AC * transitions using the biquadratic [14][15][16][17][18] and both the bilinear and biquadratic couplings [19,20] in our earlier studies.…”