Investigation of the systematics of CMXD at the L_2,3 edges in (RE)₂Co₁₇

We have performed systematic investigations of the circular magnetic x-ray dichroism, i.e., the spin-dependent absorption of circularly polarized x rays at the L_2,3 edges of the 4f elements in the compound (RE) ₂Co₁₇. In all systems significant CMXD signals with relative large amplitudes of some percent have been found. It is expected, that the spin-dependent absorption profile reflects the spin-density of d-like unoccupied states at the Fermi level and thus contains information on the orientation of the 4f moment. The ratio of the CMXD signal at the L₂ and L₃ edges depends strongly on the angular momentum of the 4f core and indicates in case of Ce₂Co₁₇, that the 4f electrons are of itinerant character with almost quenched angular momentum, as theoretically expected for similar Ce systems.