Structural and magnetic properties of a new and ordered quaternary alloy MnNiCuSb (SG: F4¯3m)

Abstract

a b s t r a c tWe have synthesized a new crystallographically ordered quaternary Heusler alloy, MnNiCuSb. The crystal structure of the alloy has been determined by Rietveld refinement of the powder X-ray diffraction data. This alloy crystallizes in the LiMgPdSb type structure with F43m space group. MnNiCuSb is a ferromagnet with a high T C $ 690 K and magnetic moment of 3.85 mB/f.u. Besides this we have also studied two other off-stoichiometric compositions; one Cu rich and the other Ni rich (MnNi 0.9 Cu 1.1 Sb and MnNi 1.1 Cu 0.9 Sb) which are also ferromagnets. It must be stressed that MnNiCuSb is one of the very few known, non-Fe containing quaternary Heusler alloys with 1:1:1:1 composition.