Magnetic states of C-doped Ni_43.75Co_6.25Mn_37.5In_12.5Heusler alloys

Abstract

Abstract. In this study, we present the results of first principles calculations of structural and magnetic equilibrium states of carbon doped Ni1.75Co0.25Mn1.5In0.5 Heusler alloy. The pseudopotential method within spin-polarized generalized gradient approximation is used. Different distributions of Mn, In and C atoms as well as different spin reference states are discussed by using a supercell approach. The ferromagnetic cubic austenite with substitution of C for Mn is found to be energetically stable. The addition of carbon has promoted the martensitic transformation from a ferromagnetic cubic structure to a ferrimagnetic tetragonal structure with c/a ratio of 1.35.