Circular Magnetic X-Ray Dichroism at the<i>K</i>-Absorption Edge in Fe–Ni Alloys

Abstract

The first systematic measurements of circular magnetic X-ray dichroism (CMXD) effects at the K -edge in 3 d -transition metal alloys have been made in Fe–Ni alloy over a wide composition range. It has been found that the CMXD spectrum at the Fe K -edge is similar to that at the Ni K -edge in each alloy, indicating that the CMXD spectra at the K -edge mainly reflect an itinerant character of 4 p -states. The features of the CMXD spectra correspond to those of X-ray absorption near-edge structure (XANES) spectra, reflecting the change of crystal structure. The signal intensities around the absorption edge energy, E 0 , have strong Ni concentration dependence, suggesting a close relationship between the CMXD effects around E 0 and the spin polarization of 3 d -states.