ELECTROCLINIC EFFECT IN A LIQUID-CRYSTAL WITH CHIRAL NEMATIC AND SMECTIC-A PHASES

The electroclinic effect is studied in a compound that presents a chiral nematic-smectic- A phase sequence. The induced tilt angles are measured as a function of the applied electric fields in both phases. A strong deviation from the linear relationship between the tilt and the applied field is observed, especially in the case of the smectic- A phase. In addition, detailed measurements of the critical behavior of the electroclinic effect at the nematic-smectic- A phase transition are presented. The results are analyzed in the framework of the available theoretical models. Other possible alternatives that could account for the behavior observed at the transition are discussed qualitatively.