Origin and properties of the gap in the half-ferromagnetic Heusler alloys

By I. Galanakis, P. Dederichs, N. Papanikolaou. 2002

586 citations recorded by the source corpus.

We study the origin of the gap and the role of chemical composition in the half-ferromagnetic Heusler alloys using the full-potential screened Korringa-Kohn-Rostoker method. In the paramagnetic phase the C1 b compounds, like NiMnSb, present a gap. Systems with 18 valence electrons, Z t , per unit cell, like CoTiSb, are semiconductors, but when Z,> 18, antibonding states are also populated, thus the paramagnetic phase becomes unstable and the half-ferromagnetic one is stabilized. The minority occupied bands accommodate a total of nine electrons and the total magnetic moment per unit cell in μ B is just the difference between Z, and 2 ×9. While the substitution of the transition metal atoms may preserve the half-ferromagnetic character, substituting the sp atom results in a practically rigid shift of the bands and the loss of half-metallicity. Finally we show that expanding or contracting the lattice parameter by 2% preserves the minority-spin gap.

Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/3e081b58ac35f225c49457bd21d8f8f19e5844a6

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Citations in the corpus

Heusler 4.0: Tunable Materials (2016, methodology): “Further half-metallic ferrimagnetic Mn2VZ-Heusler compounds were predicted by DFT based computations (37, 38, 39).”
First principles design of spintronics materials (2016, background): “Half Heusler alloys can be HMFs when they obey the rule of Mt = Zt − 18, such as in the case of the NiYSb and CoYSb compounds, where Y accounts for V, Cr, and Mn [50].”
Half-metallic ferromagnets: From band structure to many-body effects (2007, methodology): “Several explanations of the band gap have been given in terms of a Ni-Mn interaction only (Galanakis et al., 2002a).”