Study on the SmA-SmC_α^* Phase Transition by Means of Nonlinear Dielectric Measurements

Abstract

We have performed precise measurements of the third-order dielectric constant in an antiferroelectric liquid crystal MHPOCBC. In the vicinity of the SmA-SmC phase transition point, an anomalous increase of it was observed. We have developed a Landau theory taking into account the pretransitional fluctuations and show that the fluctuation can contribute to the third-order response. The anomalous behavior near the transition point was discussed on the basis of the theoretical results.