Hartree–Fock study of orbital magnetic moments in 3 d and 5 f magnets and X‐ray magnetic circular dichroism

The spin ( M s ) and orbital magnetic moments ( M o ) of the uranium 5 f state in the ferromagnetic compound uranium sulfide (US) and of the cobalt 3 d state in various transition‐metal superlattices are calculated on the basis of a tight‐binding model, in which the intra‐atomic f – f or d – d multipole interaction is taken into account using the Hartree–Fock (HF) approximation. The parameters in the model are determined on the basis of available first‐principles calculations. For US, the calculated ratio M o / M s and magnetic circular dichroism spectrum for U M 4,5 absorption are in good agreement with the experimental results. Inclusion of the expectation values of the spin‐off‐diagonal operators in addition to the number operators in the 5 f state is found to be crucially important when describing the 5 f magnetic state. A difference in enhancement of M o of the Co atom between the Co/Pd and Co/Cu superlattices is discussed on the basis of a semi‐quantitative calculation, assuming ferromagnetism.