ChemInform Abstract: Two‐Dimensional Superdegeneracy and Structure—Magnetism Correlations in Strong Ferromagnet, Mn₂Ga₅.

Abstract

5 . -The title compound is synthesized from the elements by a self-flux route (700°C, 10 h) and by solid state reaction (500°C, 10 d). The samples are characterized by single crystal XRD, magnetic measurements, and electronic band structure calculations employing FPLO, LMTO, and extended Hueckel tight-binding methods. The compound crystallizes in the tetragonal space group P4/mbm with Z = 2. The structure exhibits a three-dimensional Ga network made up of two crystallographically different types of Ga atoms. Mn2Ga5 exhibits a saturated magnetic moment of 2.71 µB per formula unit with TC ≈ 450 K. The nonmagnetic electronic structure of Mn2Ga5 reveals remarkably flat degenerate (superdegenerate) bands in the vicinity of the Fermi level. The resulting high density of states at the Fermi level is consistent with the Stoner condition for the observed itinerant electron ferromagnetism. -(KIM, S.-H.; BOSTROEM, M.; SEO*, D.-K.; J.