Neutron diffraction study of the incommensurate magnetic phase of Ni0.92Zn0.08Br2

Abstract
The magnetic structure of Ni0.92Zn0.08Br2 has been studied by single-crystal neutron diffraction as a function of temperature down to 4.2K and in magnetic fields along (110) up to 3 T. From TN=48.0+or-0.5K to TIC=21.0+or-0.5K the magnetic structure is a collinear easy-plane metamagnetic one like NiCl2. Below TIC it transforms to an incommensurate structure with a propagation length within the basal plane which decreases continuously with decreasing temperature, reaching 71+or-5 AA at 4.2K. Exploration of the scattering in the a*b* plane around (003/2) and (101/2) shows satellite structure best fitted to a ring, i.e. to a completely disordered propagation direction. The magnetic phase diagram has also been determined.