Study of the Bend Elastic Constant near a Smectic-A—Nematic Phase Transition

Abstract

The temperature dependence of the bend elastic constant of N-$p$-cyanobenzilidene-$p-n$-octyloxyaniline near the smectic-$A$—nematic transition temperature $T_c$ is found to obey the power law ${(T-{T_c}^{*})}^{-{\gamma }_3}$ with classical values for ${\gamma }_3$ in purer samples. Deviations from this value are discussed. Scanning calorimetry indicates that for purer samples the transition is either weakly first order or a $\lambda$ transition.