Ordering and the nature of the spin flop phase transition in MnPS3

Powder diffraction patterns were measured on a high quality sample of manganese thiophosphate, MnPS 3 , at temperatures between 2 and 120 K and magnetic fields between 0 and 60 kOe. In zero field, the magnetic moments in MnPS 3 are collinear and normal to the ab planes. On applying a sufficiently large magnetic field along the normal to the ab plane, it was found that the moments flop towards the b axis, in agreement with a dipole-dipole interaction model for the anisotropy. The width of this transition was found to be greater than 20 kOe. No evidence for critical fluctuations was seen during the spin flop phase transition.