The crystal and magnetic structure of the magnetocaloric compound FeMnP0.5Si0.5

The crystal and magnetic structure of the magnetocaloric compound FeMnP0.5Si0.5 has been studied by means of neutron and X-ray powder diffraction. Single phase samples of nominal composition FeMnP0.5Si0.5 have been prepared by the drop synthesis method. The compound crystallizes in the Fe2P-type structure (P6¯2m) with the magnetic moments aligned along the a-axis. It is found that the Fe atoms are mainly situated in the tetrahedral 3g site while the Mn atoms prefer the pyramidal 3f position. The material is ferromagnetic (TC=382 K) and at 296 K the total magnetic moment is 4.4μB/f.u. It is shown that the magnetic moment in the 3f   site is larger (2.5μB) than in the 3g   site (1.9μB).

The magnetic structure of FeMnP0.5Si0.5 at 296 K. Revealed from refinements of neutron powder diffraction data.Figure optionsDownload as PowerPoint slideHighlights
► Single phase samples of the compound FeMnP0.5Si0.5 has been synthesized by the drop synthesis method.
► The crystal and magnetic structure was revealed from neutron powder diffraction data.
► The material was found to crystallize in the Fe2P-structure (P6¯2m).
► The magnetic moments are coordinated along the a  -axis with a total moment of 4.4μB.
► The large magnetic moments make FeMnP0.5Si0.5 useful in magnetocaloric applications.