THE SPECIFIC-HEAT AND CRITICAL-BEHAVIOR OF VBR2, A HEISENBERG-ANTIFERROMAGNET WITH CHIRAL-SYMMETRY

We present high-resolution measurements of the specific heal, C, of th e Heisenberg antiferromagnet VBr2 With layered-triangular lattice in t he temperature range between 1.5 and 35 K and in fields up to 6 T The critical exponent alpha extracted from C has been obtained as alpha = 0.30 +/- 0.05. This value is fully consistent with the theoretically e xpected exponent of alpha = 0.24 +/- 0.08 for three-dimensional Heisen berg systems with chiral symmetry.