Optical and dielectric investigations on the electroclinic effect exhibited by a ferroelectric liquid crystal with high spontaneous polarization

Abstract

The electroclinic effect in the smectic A phase of 4-(3-methyl-2-chlorobutanoyloxy)-4'-heptyloxybiphenyl has been investigated. Values up to 10° are obtained for the induced tilt angle, which is proportional to the applied d.c. field. The amplitude of the tilt angle modulation shows exactly the same dependence on temperature and frequency as the dielectric constant which indicates a linear coupling between the tilt angle and the polarization. The relaxation frequency increases linearly with temperature from 0.4 MHz at the S_A—S∗_C transition to 3.5 MHz near the S_A-I clearing point. Optical switching times below 0.5 μs were established.