Very slow hysteresis loops in ferroelectric liquid crystals

Abstract

We report an optical technique for quantitative studies of switching processes in ferrolectric liquid crystals. The molecular reorientational changes are directly recorded as a function of the exciting electric field. Therefore similar and complementary information to that obtained by means of the polarization current measurements can be deduced. The method is specially designed for very low frequency regimes (≤0.1 Hz) where it has the advantage over the polarization technique of being free from spurious conductive and capacitive contributions. The performing features of the method are illustrated by studying the switching process of a 9 μm thick sample of DOBAMBC under a triangular wave of 0.03 Hz.