MAGNETIC CIRCULAR X-RAY DICHROISM SPECTRA AT L-2,L-3 EDGES OF RARE-EARTH COMPOUNDS

We report a systematic interpretation of the trend observed in the mag netic circular X-ray dichroism (MCXD) at the L-2,L-3 edges for the ent ire series of rare-earth elements. It is shown that the MCXD spectra c onsisting mainly of the electric dipole transition are dominated by th e enhancement of the dipole matrix element as well as by the polarizat ion effect of the 5d ground state, both of which are due to the 4f-5d exchange interaction. A complemental contribution from the electric qu adrupole transition is found to be appreciable, by reproducing the exp erimental spectra as a superposition of both contributions. (C) 1998 E lsevier Science B.V. All rights reserved.