Dielectric-relaxation study of alkylcyanobiphenyl liquid crystals using time-domain spectroscopy

Abstract

Time-domain spectroscopy is used to study the complex permittivity of two types of liquid crystals: heptylcyanobiphenyl (7CB) and octylcyanobiphenyl (8CB). The variation of the dominant relaxation frequency values of both 7CB and 8CB as a function of temperature are very similar, showing no influence of the smectic structure in 8CB. The experimental relaxation measurements in the nematic phase agree qualitatively with the existing theory.