STRONG FINAL-STATE EFFECTS IN L-2,L-3 XMCD OF IONIC RARE-EARTH MATERIALS

The L-23 XMCD spectra of rare earth insulating systems show line shape s that look like a derivative of the near-edge XAS spectra. This line shape is shown to be due to intra-atomic final state Coulomb interacti ons between the 2p --> 5d excited photoelectron and the magnetically a ligned 4f shell. An atomic multiplet calculation starting from a 4f (N )5d(0) initial state gives good agreement with the observed line shape s. The experimental fact that the temperature dependence of the XMCD f ollows that of the 4f moment supports such a local description. Furthe rmore, an analysis in terms of spectral moments based on the 5d(0) ass umption yields sum rules for the first moments of the edges that expla in the trends in literature data for metallic systems.