Electrooptic Measurement in the Vicinity of SmA-SmC_α ^* Phase Transition of an Antiferroelectric Liquid Crystal

Abstract

Electrooptic measurements have been performed around the SmA-SmC α * phase transition point in an antiferroelectric liquid crystal 4-(1-methyl-heptyloxycarbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate (MHPOBC). The first-order electrooptic response was continuous with a small slope change at the SmA to SmC α * transition point in the temperature dependence curve, while the second-order electrooptic response exhibited an anomalous increase near the transition point. We present a simple theory and demonstrate that this anomaly originates in the pretransitional fluctuations. The frequency dispersion of the electrooptic response is also presented.