Specific-heat critical behavior of CsMnBr sub 3 and holmium: Two tests of chiral universality

Specific-heat ({ital C}{sub {ital p}}) measurements have been made near the {ital H}=0 phase transition in CsMnBr{sub 3}, an {ital XY} stacked triangular antiferromagnet, and Ho, a helical antiferromagnet. Previous neutron-scattering experiments indicate both to be prime candidates for chiral universality. {ital C}{sub {ital p}} vs {ital T} data for CsMnBr{sub 3} yield {alpha}=0.39{plus minus}0.09, in agreement with Monte Carlo results; however, data for Ho show quite a different behavior.