6533b854fe1ef96bd12af21c

RESEARCH PRODUCT

Element-specific magnetic moments and spin-resolved density of states in CoFeMnZ(Z=Al, Ga; Si, Ge)

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Using circular dichroism in x-ray-absorption spectroscopy (XAS/XMCD), we determined element-specific magnetic moments and spin-resolved unoccupied densities of states (DOS) for Co, Fe, and Mn in the quaternary Heusler compounds CoFeMn$Z$ ($Z=\text{Al}$, Ga; Si, Ge). These compounds belong to a class of highly spin-polarized materials with cubic LiMgPdSn-type structure. Different structure models for the sublattice occupation leading to similar average magnetization values can be distinguished by comparison of element-specific moments with theory. We find that the compounds form similar structures, where Co, Fe, Mn, and $Z$ occupy the $X$, ${X}^{\ensuremath{'}}$, $Y$, and $Z$ sublattice of the related ${X}_{2}YZ$ $L{2}_{1}$-Heusler structure, for which half-metallic behavior was predicted. The unoccupied partial DOS as derived from the XAS/XMCD spectra for Co, Fe, and Mn are compared to theoretical results. A good agreement is found for Co and Fe, while Mn spectra reveal additional final-state effects (multiplets).