FIELD DEPENDENCE OF THE STATIC SOFT MODE SUSCEPTIBILITY AT THE SmA-SmC* PHASE TRANSITION

Abstract

Two multicomponent liquid crystal mixtures showing the second order smectic A - ferroelectric smectic C* phase transition and high spontaneous polarization in the chiral smectic C* phase have been studied with an aim to understand the field behaviour of the soft mode susceptibility maximum at the transition. Both the shift of the temperature and the field induced decrease in the height of the susceptibility maximum were shown to be controlled by the bδ⁴ term in the classical Landau expansion. From these dependences the tilt-polarization coupling constants at the phase transition have been calculated to be in agreement with the values found from independent measurements of the tilt angle and polarization for the same mixtures.