High-resolution heat-capacity experiments on free-standing films of the liquid-crystal compound 3(10)OBC near the smectic-A–hexatic-B phase transition have been conducted. The hexatic-B phase has been found to propagate into the smectic-A phase through a series of layer transitions, each appearing to be continuous. Furthermore, the evolution of the layer-by-layer transitions is shown to be inconsistent with recent theory regarding the fluctuation-induced forces of the highly anisotropic smectic phases.

• Received 11 June 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.2090