X-ray2pphotoelectron andLαresonant x-ray emission spectra of the3dmetals inNi2MnZ(Z=In,Sn,Sb)Heusler alloys

Abstract

Magnetic and chemical bonding effects in Heusler alloys ${\mathrm{Ni}}_{2}\mathrm{Mn}\mathrm{In}$, ${\mathrm{Ni}}_{2}\mathrm{Mn}\mathrm{Sn}$, and ${\mathrm{Ni}}_{2}\mathrm{Mn}\mathrm{Sb}$ were studied by soft x-ray spectroscopy. Exchange splitting detected in Mn $2p$ core-level x-ray photoelectron spectra and an increase of the Mn ${L}_{\ensuremath{\beta}}∕{L}_{\ensuremath{\alpha}}$ intensity ratio in nonresonant x-ray emission spectra show that atomic magnetic moment at Mn is higher than that of pure metal. Spin polarized density of states calculations and comparative analysis of Mn and Ni ${L}_{\ensuremath{\alpha}}$ resonant x-ray emission spectra (RXES) demonstrate that the spin splitting in Mn $3d$ shell is larger than in Ni $3d$ shell. The $d\text{\ensuremath{-}}d$ transitions observed in ${L}_{\ensuremath{\alpha}}$ RXES of Mn and Ni are suggested to be more intensive for Mn than for Ni valence electrons when initiated by off-resonant excitations. Experimental findings are supported by photoelectron spectra calculations and developed two-step model of resonant x-ray emission. The interplay between Mn ${L}_{\ensuremath{\alpha}}$ RXES and calculated magnetic moments of Mn atoms in alloys as a function of the type of $Z$ element is discussed.