4F ORBITAL AND SPIN MAGNETISM IN CERIUM INTERMETALLIC COMPOUNDS STUDIED BY MAGNETIC CIRCULAR X-RAY DICHROISM

Magnetic circular x-ray dichroism experiments at the M4,5 absorption e dges of cerium in the intermetallic compounds CeCuSi, CeRh3B2, and CeF e2 are reported. By applying general sum rules, it is shown that these experiments are able to yield both the magnitude and the direction of the 4f magnetic moment on Ce. An estimation of the orbital contributi on to those 4f moments is given. Our experiments demonstrate the exist ence of a 4f magnetic moment on Ce in CeFe2 and confirm the extreme se nsitivity of the 4f orbital contribution to the degree of localization of the 4f electrons. This 4f orbital contribution is significantly hi gher than the one predicted from spin-resolved band-structure calculat ions.