Ferromagnetic-Alloy Phases Near the Compositions Ni2MnIn, Ni2MnGa, Co2MnGa, Pd2MnSb, and PdMnSb

Abstract

In a search for further examples of Heusler-type alloys, ferromagnetic alloys were found near the composition Ni2MnIn, Ni2MnGa, Co2MnGa, Pd2MnSb, and PdMnSb. The first four alloys are tentatively identified as having the L21(Heusler)-type structure; PdMnSb, the Cl1-type structure. Previous work has indicated that ferromagnetism in these types of alloys is associated with Mn-Mn distances in the range 4.17–4.37 A. The present work indicates that ferromagnetism persists with Mn-Mn distances as small as 4.08 A (Co2MnGa) and as large as 4.42 A (PdMnSb); and that ferromagnetism disappears if the Mn-Mn distances become too large. Pd2MnSb, with Mn-Mn distance 4.55 A, is only feebly magnetic at room temperature.