title: Characterization of the smectic-A-hexatic-B transition in 650BC by adiabatic scanning calorimetry.
abstract: We investigated the smectic-A-hexatic-B (SmA-HexB) transition in the liquid-crystal n-hexyl-4'-n-pentyloxybiphenyl-4-carboxilate (650BC) with adiabatic scanning calorimetry. We were able to prove in a direct way that this transition is indeed very weakly first order, as was already suggested in the literature. The latent heat at the transition was determined to be deltaHL = 0.04 +/- 0.02 J/g. Our experiments confirm the high value for the heat capacity critical exponent earlier reported, yielding alpha = 0.64 +/- 0.05.
authors.affiliation: Laboratorium voor Akoestiek en Thermische Fysica, Departement Natuurkunde en Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium. Bert.VanRoie@fys.kuleuven.ac.be
authors.forename: B
authors.initials: B
authors.lastname: Van Roie
authors.forename: K
authors.initials: K
authors.lastname: Denolf
authors.forename: G
authors.initials: G
authors.lastname: Pitsi
authors.forename: J
authors.initials: J
authors.lastname: Thoen