Depth selective investigations of magnetic multilayers by X-ray resonant magnetic reflectivity

We have measured and analyzed the X-ray resonant Bragg reflectivity spectra from BCC [Fe/Co](n) superstructure near the L-2,L-3 absorption edges of iron. The developed general computer code for the reflectivity calculations from arbitrary anisotropic multilayers allows us to test the different approaches to the treatment of the Bragg reflectivity spectra. We have proved that the observed asymmetry of the spectrum shape at the first-order Bragg peak for the right and left circular polarizations is predominantly caused by the magnetization of the central part of iron layers. The influence of interfaces is almost negligible. The fit of the energy dependence of the integral intensity of the Bragg reflection for the [Fe-6/Co-6](50) sample gives the value of the magnetic moment of Fe atoms in the central parts of Fe layers similar to 2.6 mu(B), that is larger than the volume value. (C) 2005 Elsevier B. V. All rights reserved.