MAGNETIC EXAFS

The occurrence of a magnetic contribution in the EXAFS regime is a com plex problem but interesting phenomenon since it is expected to contai n unique information on the magnetic short-range order. Experimental s tudies of the small effects with sufficient high accuracy are required to provide the possibility of a reliable data analysis and interpreta tion. This is often hampered by the occurence of strong magnetic multi -electron effects and low-frequent atomic contributions as well as the strongly enhanced magnetic multiple scattering. Concerning the theore tical treatment problems arise, because the spin-dependency has to be included correctly and spin-orbit and exchange interaction have to be treated on the same level especially for higher photo-electron energie s. Here we try to show, that by introduction of an additive spin-depen dent part of the complex scattering amplitude for a spin-polarized out going photo-electron wave a reasonable interpretation of the experimen tal data is possible in a first approximation. The results of systemat ic measurements demonstrate the potential of this method to study magn etic and crystallographic structures and the low-energy exchange scatt ering process even in a quantitative manner.