Effect of the hexatic-B temperature range on the nature of the smectic-Ahexatic-B phase transition

High-resolution heat-capacity measurements have been carried out on several pure compounds and binary mixtures in the homologous series of n-alkyl-4-n-decyloxybiphenyl-4-carboxylate. The measured smectic-Ahexatic-B heat-capacity anomalies can be fitted to a power law over two decades in the reduced temperature with a large value for the critical exponent (=0.60). The value of ± remains fairly constant when the hexatic-B phase temperature range varies from 0.8 to 22 K.