Specific-heat critical behavior of CsMnBr3 and holmium: Two tests of chiral universality

Specific-heat (Cp) measurements have been made near the H=0 phase transition in CsMnBr3, an XY stacked triangular antiferromagnet, and Ho, a helical antiferromagnet. Previous neutron-scattering experiments indicate both to be prime candidates for chiral universality. Cp vs T data for CsMnBr3 yield α=0.39±0.09, in agreement with Monte Carlo results; however, data for Ho show quite a different behavior.