X-ray 2p photoelectron and L-alpha resonant x-ray emission spectra of the 3d metals in Ni(2)MnZ (Z=In,Sn,Sb) Heusler alloys

Abstract

Magnetic and chemical bonding effects in Heusler alloys Ni2MnIn, Ni2MnSn, and Ni2MnSb 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-beta/L-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-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-d transitions observed in L-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-alpha RXES and calculated magnetic moments of Mn atoms in alloys as a function of the type of Z element is discussed.