Dielectric relaxations in a liquid crystal with helicoidal dipole ordering

Abstract

We have measured the dielectric relaxations of a ferroelectric liquid crystal in a very large interval of frequency : from 25 Hz to 600 MHz with the electric field parallel or perpendicular to the layer planes. We found two relaxations in the isotropic phase, four in the Sm A phase and seven in the Sm C* phase. We give a satisfactory assignment of these relaxations using theoretical calculations, if we suppose that some molecular dipoles participate to the dipole ordering while others do not.