Atomic magnetic moment and X-ray photoelectron spectra of Fe-based crystalline and amorphous alloys

X-ray photoelectron spectra of the valence band and Fe 2p(3/2) and 3s core levels have been measured both for polycrystalline Fe-Cr alloys and amorphous Fe-B alloys. The 3s-multiplet splitting has been used to estimate the local magnetic moment of Fe atoms. To explain the observed concentration dependence of the magnetic moment, the calculations of the electronic structure and the magnetic moment of the Fe atoms were performed in the framework of the tight-binding coherent potential approximation. Results of the calculations agree with the experimental concentration dependence of the magnetic moment of Fe atoms, This dependence of the atomic magnetic moment on a boron concentration for amorphous Fe-B alloys obeys the Slater-Pauling rule on going from 15.5 to 19.5 at.% but shows a slight deviation from this linear behaviour at about 15 at.%. For Fe-Cr, alloys the atomic magnetic moment is almost constant for differences of components concentration in agreement with X-ray photoemission spectroscopy measurements, whereas the average magnetic moment of the alloy decreases almost linearly with increasing Cr concentration. The difference in concentration dependence of the atomic magnetic moment is explained in terms of a charge transfer between s, p and d bands which is found to be larger for the amorphous Fe-B alloys than for the polycrystalline Fe-Cr alloys.