ORBITAL AND SPIN MOMENTS IN URANIUM-COMPOUNDS FROM X-RAY MAGNETIC CIRCULAR-DICHROISM

The knowledge of the orbital (mu(L)) and spin (mu(S)) magnetic moments of a magnetic material is fundamental for the understanding of its ba sic properties. X-ray Magnetic Circular Dichroism (XMCD) at the uraniu m M-edges (3.5-3.8 keV) of a ferromagnet is a new tool which provides a direct and independent determination of mu(L) and mu(S) using sum ru les. Here we report on recent XMCD experiments performed on uranium co mpounds with different degree of hybridization USb0.5Te0.5 (localized) , UFe2 (strongly hybridized) and US (weakly hybridized). The results a re compared to those obtained from the analysis of the magnetic form f actor deduced from neutron scattering experiments. The importance of t he value assigned to the magnetic spin dipolar operator < T-2> is emph asized. (C) 1998 Elsevier Science S.A.