High resolution powder neutron diffraction on the incommensurate magnetocaloric material MnZnSb

The domestic refrigerators that are currently in use are energy inefficient and require harmful gases to operate. A viable alternative cooling system is magnetic refrigeration, which require materials that exhibit the magnetocaloric effect. Recently, pronounced magnetocaloric properties have been observed in MnZnSb. This is reported to have a PbFCl-like structure with some ‘disorder’ that isn’t understood. We observe evidence of modulations and lowering of symmetry in diffraction patterns, but we require high resolution powder neutron diffraction to resolve it. The key objectives of the experiment are: 1) Determine the nuclear and magnetic structure of MnZnSb around the magnetic transition temperature (302K) to understand the magnetocaloric effect observed in this compound and 2) Determine the nuclear structure below a structural transition observed at 130K which hasn’t been reported.