Nonlinear Behaviors of Electroclinic and Dielectric Constants at the Smectic A-Smectic C* Phase Transition

The applied electric field dependences of the field-induced tilt angle and electric displacement are studied in the SmA phase of a ferroelectric liquid crystal. The electroclinic constant and nonlinear dielectric constants obtained from the measured data increase in their magnitude on approaching to the SmA-SmC* phase transition temperature. The temperature dependences of these constants are in a good agreement with those predicted by the phenomenological theory of Landau type for the phase transition, and the phenomenological parameters appearing in the theory can be determined from these constants.