Neutron scattering has been used to measure the critical behaviour of the sublattice magnetization, M, and the gap in the spin wave energies at the Brillouin zone centre, E-0, for a single crystal of the quasi-2D antiferromagnet, MnPS3. The system was previously believed to be a good example of a Heisenberg-like antiferromagnet, however, the critical behaviour over most of the temperature range is more representative of an XY-like system. Just below the Neel temperature, there appears to be a cross-over to 3D critical behaviour. This signature is seen in the temperature dependences of both M and E-0. The nature of the anisotropy, which appears to be the final obstacle to a full understanding of the critical properties of MnPS3, is discussed. (c) 2006 Elsevier B.V. All rights reserved.
Henrik Moodysson Rønnow, Jonathan White
Bruce Normand, Ying Chen, Sheng Xu, Shuo Li, Xiaoyu Xu, Zeyu Wang, Weiqiang Yu