Local moments in Mn-based Heusler alloys and their electronic structures

In this article we present a detailed study of the electronic structure fro m various Mn-based Heusler alloys using x-ray photoelectron spectroscopy (X PS) and x-ray emission spectroscopy (XES) techniques. Performing the measur ements on the Mn-2p core levels as well as on the valence-band states we ar rive at a more or less complete description of the electronic and magnetic properties of these compounds. The experimental Mn-2p spectra have been com pared with fully relativistic photoemission calculations, which are based o n the solution of the spin-polarized Dirac equation. The almost constant ex change splitting of about 0.35 eV, measured between the different Mn-2p sub levels is explainable in terms of the local magnetic moment at the Mn site. Moreover a strong relationship between the magnetization direction and the line shapes of the calculated Mn-2p core-level spectra has been revealed f rom our analysis. Depending on the atomic number of the Z element we obtain from XES experiments an increasing localization of the Mn-3d states. Also the interatomic distances in the different alloys seem to play an important rule in this process. To support this result we performed in addition vale nce-band measurements by applying XP. These data, which agree very well wit h the corresponding x-ray emission spectra are quantitatively reproduced fr om first-principle electronic structure calculations. [S0163-1829(99)09233- 4].