High-field magnetic structure and critical phenomena in MnWO4

The magnetic structure of the high-held phase HF in MnWO4 was resolved by single-crystal neutron diffraction at 14.5 T and 2.5 K. It is a spin-flop phase with the same magnetic unit cell as the magnetic ground state, but the magnetic moments switched perpendicular to the applied field. The temperature dependence of the propagation vector for the intermediate, incommensurate phase indicates that the coexistence point of HF, the intermediate phase, and the paramagnetic region might be a Lifshitz-point. (C) 2000 Elsevier Science B.V. All rights reserved.