ELECTRONIC STRUCTURE AND MAGNETIC PROPERTIES OF HEUSLER ALLOYS MMnSb (M = Ni, Pd, Pt)

The energy, charge, and spin characteristics of the MMnSb (M = Ni, Pd, Pt) alloys have been obtained using band calculations in the framework of the full-potential linearized augmented plane-wave (FLAPW) model. The obtained data show that, owing to an increase of the covalent atomic interaction, the cohesive energies monotonically increase along the alloy series PdMnSb-NiMnSb-PtMnSb, with the indicated alloys being ferromagnetically ordered and characterized by the enhanced localization of magnetic moments at the manganese atoms. It is found that the main contribution to the formation of magnetic moments in the alloys is made by 3d-electrons of the manganese atoms. The dominant role is played by electrons on the t(2g)-orbital, and the less one by electrons on the e(g)-orbital. The contribution of the s- and p-electrons of Mn atoms and the electrons of other atoms to the formation of magnetic moments of the examined alloys is found to be small.