High resolution x-ray measurements on smectic cliquid crystal mixtures

Abstract

We report on high resolution x-ray measurements of two commercial ferroelectric liquid crystal mixtures. Both materials show a second order smectic A* to smectic C* phase transition. The measured tilt angle, Φ_p was fitted to the power law expression Φ_p = Φ o^{t −β} (with the reduced temperature, t = (T_c - T)/T_C; T_C is the smectic A to smectic C* phase transition temperature), giving β = 0.31 ± 0.02 for one and β = 0.33 ± 0.03 for the other mixture. We discuss the discrepancy between the x-ray tilt angles and those obtained by conventional optical methods.