Analysis of the Order Parameters (Spontaneous Polarization and the Tilt Angle) and the Critical Field Close to the Smectic A-Smectic C* Transition in HDOBAMBC

作者：Yurtseven H^*; Eren D; Abdelal A

来源：Ferroelectrics, 2014, 467(1): 126-137.

DOI：10.1080/00150193.2014.932588

• Spontaneous polarization
• tilt angle
• critical electric field
• smectic A-smectic C* transition
• HDOBAMBC

We introduce a mean field model to describe the smectic A-smectic C* (AC*) transition in HDOBAMBC. Our mean field model considers a linear coupling between the spontaneous polarization (P-s) and the tilt angle (theta) in the presence of the electric field coupled to the spontaneous polarization. From our model, we derive the expression for P-s, theta and the critical field E-c as a function of temperature. The temperature dependences of the order parameters (spontaneous polarization P-s and the tilt angle theta) and the critical electric field E-c are analyzed using the experimental data from the literature according to power-law formulae close to the smectic A-smectic C* transition (T-c = 109.7 degrees C) in HDOBAMBC. From our analyses, we obtain the values of beta = 0.24 and phi = 0.42 for the critical exponent of the spontaneous polarization P-s and the tilt angle theta, respectively in HDOBAMBC. We also obtain from our analysis the values of delta = 0.46 and delta = 0.27 for the critical exponent of the critical electric field E-c away from the T-c (AC*) and close to the T-c (AC*), respectively in HDOBAMBC.
Our results indicate that a mean-field to tricritical crossover behaviour can occur in the ferroelectric liquid crystal of HDOBAMBC.

• 出版日期2014