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Theoretical study of the ferromagnetism in UNi sub 2

Journal Article · · Physical Review, B: Condensed Matter; (United States)
;  [1];  [2];  [1]
  1. Condensed Matter Theory Group, Department of Physics, University of Uppsala, Box 530, S-75121 Uppsala (Sweden)
  2. Commission of the European Communities, European Institute for Transuranium Elements, Postfach 2340, D-7500 Karlsruhe (Germany)

Electronic-structure calculations for the ferromagnet UNi{sub 2} in the hexagonal MgZn{sub 2} structure ({ital C}14) are reported. In this treatment the uranium 5{ital f} electrons are considered as itinerant and are included in the self-consistent local-density calculations on the same footing as the other valence electrons. By adding the spin-orbit interaction and orbital polarization to the Hamiltonian, a substantial cancellation between the spin and orbital moments on the uranium atom is obtained. This is in good qualitative agreement with neutron-scattering experiments and can only be achieved by inclusion of the orbital polarization. From fixed-moment calculations, where the total magnetic moment is chosen to agree with data, a good agreement with the experimental uranium form factor is obtained. We emphasize the contribution of the 6{ital d} electrons to the uranium magnetic form factor for small {ital Q} vectors, which in fact gives rise to a substantial improvement of the agreement with data when compared to an unconstrained fit where only 5{ital f} contributions to the uranium magnetic density are taken into account. The magnetism in UNi{sub 2} is found to be driven by the uranium atoms, in contrast to the related system UFe{sub 2} in which it is caused by the iron atoms.

OSTI ID:
6259830
Journal Information:
Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:17; ISSN 0163-1829; ISSN PRBMD
Country of Publication:
United States
Language:
English