Magnetic EXAFS

The occurrence of a magnetic contribution in the EXAFS regime is a complex problem but interesting phenomenon since it is expected to contain unique information on the magnetic short-range order. Experimental studies of the small effects with sufficient high accuracy are required to provide the possibility of a reliable data analysis and interpretation. 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 theoretical 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 energies. Here we try to show, that by introduction of an additive spin-dependent part of the complex scattering amplitude for a spin-polarized outgoing photo-electron wave a reasonable interpretation of the experimental data is possible in a first approximation. The results of systematic measurements demonstrate the potential of this method to study magnetic and crystallographic structures and the low-energy exchange scattering process even in a quantitative manner.