The effect of pressure in the crystal and magnetic structure of FeWO4

The temperature dependence of the structural and magnetic properties of wolframite-type FeWO(4 )was studied in situ by high-pressure neutron diffraction. Neutron diffraction measurements were performed with the XtremeD instrument at the Institut Laue-Langevin up to a maximum pressure of 8.7(4) GPa and a minimum temperature of 30.0(5) K. The diffraction data were analyzed via Rietveld refinements. We found that despite producing a contraction of 5% of the volume, the maximum pressure applied in this study does not modify the Shubnikov space group below magnetic order. However, the orientation of magnetic moments and the Neel temperature are slightly modified with the pressure, which is expected according to the preexistent understanding of magnetism in wolframites. We also determined a pressure-volume equation of state of FeWO4 at 300 K, which is compared with previous x-ray diffraction studies and density-functional theory calculations.