Selective electronic excitations in nearly half-metallic Heusler alloy NiFeMnSn—A Raman spectroscopic study

摘要: Half-metallic ferromagnetic full Heusler alloy NiFeMnSn is a promising material in spintronic device fabrication as it carries high spin polarization and high Curie temperature (T c= 405 K). Understanding electronic excitations in a spin-polarized band structure is essential for the further use of this material in spin-based devices and to optimize the spin-dependent electronic structure in related compounds. In this Letter, we report electronic Raman scattering of NiFeMnSn with spectral signatures at a higher wavenumber than expected from the calculated phonon modes of the system. Temperature-dependent Raman spectroscopy demonstrates a non-monotonic behavior of the Raman shift with temperature across T c. The orbital resolved electronic density of states and electronic band structure for both spin channels of the system, as obtained from the first principles density functional theory calculations, suggest that …