Spin and orbital moments in actinide compounds

B. Lebech, M. Wulff, G.H. Lander

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    Abstract

    The extended spatial distribution of both the transition-metal 3d electrons and the actinide 5f electrons results in a strong interaction between these electron states when the relevant elements are alloyed. A particular interesting feature of this hybridization, which is predicted by single-electron band-structure calculations, is that the orbital moments of the actinide 5f electrons are considerably reduced from the values anticipated by a simple application of Hund's rules. To test these ideas, and thus to obtain a measure of the hybridization, we have performed a series of neutron scattering experiments designed to determine the magnetic moments at the actinide and transition-metal sublattice sites in compounds such as UFe2, NpCo2, and PuFe2 and to separate the spin and orbital components at the actinide sites. The results show, indeed, that the ratio of the orbital to spin moment is reduced as compared to the free-ion expectations. In addition there is qualitative agreement with theory, although the latter predicts values of both components that are larger than those found by experiment. Because L and S are opposed in the light actinides, and L is usually greater than S, the reduction of L can result in a situation for which L - S congruent-to O. This almost occurs in UFe2. However, neutrons are capable of observing the individual components at finite wave vector (Q), although the total component (observed at Q = 0) may indeed be close to zero.
    Original languageEnglish
    JournalJournal of Applied Physics
    Volume69
    Issue number8
    Pages (from-to)5891-5896
    ISSN0021-8979
    DOIs
    Publication statusPublished - 1991
    Event35th Annual Conference on Magnetism and Magnetic Materials - San Diego, CA, United States
    Duration: 29 Oct 19901 Nov 1990

    Conference

    Conference35th Annual Conference on Magnetism and Magnetic Materials
    CountryUnited States
    CitySan Diego, CA
    Period29/10/199001/11/1990

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