Critical scattering from paramagnetic CsMnBr3: An XY antiferromagnet with chiral degeneracy

We have measured the frequency-integrated critical scattering of neutrons from CsMnBr3. Below TN = 8.3 K, CsMnBr3 is a stacked, XY-line antiferromagnet on a triangular lattice. Analysis of the scattering shows the critical exponents γ and v to be 1.01 ± 0.8 and 0.54 ± 0.03 respectively. These values agree well with recent predictions by Kawamura in which the symmetry of the order parameter characterizes the universality class.