Anomalous hydrodynamic behaviors of smectic liquid crystals at low frequencies

We report the details of the measurements of the layer compression modulus B and the longitudinal viscosity \tildeη of several thermotropic smectic phases in the frequency range from 10 Hz to 1 kHz. We confirmed for smectic phases having liquidlike layers (including smectic-A, smectic-C and chiral smectic-C phases) that \tildeη has an anomalous frequency (ω) dependence of the type \tildeκ/ω predicted theoretically by Mazenko, Ramaswamy and Toner, and also by Katz and Lebedev. The temperature dependence of B and the strength of the anomalous viscosity \tildeκ were measured in detail, which revealed, in particular, that a close correlation exists between \tildeκ and B . We also found that, under an applied magnetic field, which tends to suppress the thermal fluctuations of smectic layers, \tildeκ decreases whereas B increases, a result which is consistent with the premise of the advocated theories.