Magnetic Structures of Iron Sulphide

The results of the first high-pressure neutron powder diffraction study of FeS, using the Paris-Edinburgh cell for sample pressure generation, are reported. Excellent agreement is obtained between the present and previously published troilite nuclear and magnetic structures. Data collected at 4.0 GPa for the MnP-type FeS phase II show that the transition to this phase is accompanied by a 90° magnetic moment reorientation, just as seen for FeS for T>TS~450 K at ambient pressure. The neutron data collected for the monoclinic FeS phase III at 9.0 GPa confirms a recent X-ray structure solution for this phase and the loss of magnetic order reported in 57Fe Mössbauer studies. [Iron sulphide, neutron diffraction, phase transitions, crystal structures, magnetic structures].