Surface molecular relaxation in smectic C∗ phase as studied by dielectric spectroscopy

Abstract

The molecular relaxation process of a ferroelectric liquid crystal with a high tilt angle and a high spontaneous polarization in a homeotropically aligned cell has been studied by the dielectric relaxation method in the frequency range 10 Hz to 10 MHz. The measurements have been done using thin (3.5μm) cells with gold coated electrodes and samples aligned by a magnetic field. It has been observed that the molecular relaxation around the short axis of the molecule is detected in the chiral nematic and smectic C∗ phases. The surface molecular process is observed in the S∗_c phase down to nearly 6 to 7 K below the transition temperature of the N∗ to the S∗_c phase. The experimental results of the surface molecular process are analysed by theoretical calculations. The experimental results agree with the theoretical predictions.