Effects of confinement and electric field on the dielectric behavior of smectic-C*α phase

Dielectric permittivity measurements are carried out to investigate the effects of confinement and electric field on a chiral smectic liquid crystal in the smectic-C*α (Sm-C*α) phase for various cell thicknesses. The Sm-A* -C*α transition temperature and the temperature range for which the Sm-C*α phase is stable decrease with decreasing cell thickness. On reducing the cell thickness, the surface-induced mode appears, as a result of the influence of the cell substrates. This increases the dielectric strength of the Sm-C*α phase. The distribution parameter of the relaxation process, α decreases significantly, and in the case of a thin cell, the decrease observed reflects a wide symmetric distribution of the relaxation process. On increasing the electric field, the dielectric strength decreases and the relaxation frequency increases in the Sm-C*α phase. These are explained by the 'helical fracture' model, originally proposed for the Sm-C* phase.