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Structural, electronic and magnetic properties of the Mn50Al46Ni4 alloy

2015; Elsevier BV; Volume: 401; Linguagem: Inglês

10.1016/j.jmmm.2015.11.011

1873-4766

Sever Mican, D. Benea, R. Hirian, Radu Cristian Gavrea, O. Isnard, V. Pop, M. Coldea,

Rare-earth and actinide compounds

The structural, electronic and magnetic behavior of the as-cast and annealed Mn50Al46Ni4 and Mn54Al46 alloys was investigated. It was found that annealing at 470 °C promotes the formation of the τ phase in both alloys, however, all of the prepared samples were phase mixtures. The τ phase was found along with the κ phase (CsCl-type structure) only in the Mn50Al46Ni4 alloy. M(T) curves show two transitions at 437 K and 634 K corresponding to the ferromagnetic κ and τ phases, respectively. A maximum τ phase content of 76 wt% for Mn54Al46 and 74 wt% for Mn50Al46Ni4 was found for the samples annealed at 470 °C for 6 h. Saturation magnetization values at 4 K of 112 Am2/Kg and 106 Am2/Kg were obtained for Mn54Al46 and Mn50Al46Ni4 respectively, in good agreement with the values reported in the literature. Band structure calculations show a preference for Ni to occupy the Mn 1a and 1c crystallographic sites, the calculated magnetic moments for Mn54Al46 and Mn50Al46Ni4 being in good agreement with the experiment. The electronic, structural and magnetic properties of these alloys are discussed as a function of composition and preparation route.