Observation of pretransitional effect of virtual SmA-SmC^* transition

Abstract

Unusual temperature dependence of layer compression modulus B has been observed in the naphtalene-based liquid crystal mixture. This unusual softening of B appears in the vicinity of the boundary where the smectic-C phase vanishes. From X-ray and layer compression measurements in the various mixing ratios of this mixture, this unusual effect is attributed to the pretransitional effect of a virtual smectic-A-smectic-C phase transition point in the Sm-A phase, which no longer appears on the thermoequilibrium phase diagram.