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Author Cornelius, A. L. ♦ Arko, A. J. ♦ Sarrao, J. L. ♦ Thompson, J. D. ♦ Hundley, M. F. ♦ Booth, C. H. ♦ Harrison, N. ♦ Oppeneer, P. M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ FERMI LEVEL ♦ ELECTRIC CONDUCTIVITY ♦ TIN ALLOYS ♦ URANIUM ALLOYS ♦ GALLIUM ALLOYS ♦ ALUMINIUM ALLOYS ♦ MAGNETIZATION ♦ SPECIFIC HEAT ♦ ANTIFERROMAGNETIC MATERIALS ♦ MAGNETIC FIELDS ♦ MAGNETIC MOMENTS ♦ DE HAAS-VAN ALPHEN EFFECT ♦ BAND THEORY
Abstract We have performed measurements of the specific heat and resistivity in static magnetic fields up to 12 T, as well as magnetic measurements in a static field of 0.1 T and in pulsed fields up to 50 T on high-quality UX{sub 3} (X=Ga, Al, and Sn) single crystals. The behavior of the electronic specific heat coefficients in applied field {gamma}(B) either remains nearly constant or increases as {ital B} increases and is inconsistent with the expectations of the single-impurity model. For UGa{sub 3}, different de Haas{endash}van Alphen (dHvA) frequencies are observed above and below a magnetic transition at a field B{sub M}{approximately}12 T at T{approximately}0.5 K, indicating that a major reconstruction of the Fermi surface occurs. Neither USn{sub 3} nor UAl{sub 3} exhibited a magnetic transition in fields to 50 T, and only a single weak dHvA frequency was observed in these compounds. The difference between the behavior of the UX{sub 3} compounds can be attributed to the degree of hybridization of the 5f orbitals with the conduction electron orbitals. UGa{sub 3} behaves as an itinerant 5f-electron system, while UAl{sub 3} has a tendency to localization, but is still relatively delocalized. USn{sub 3} is a heavy fermion compound. Concurrent to our experimental investigations we have performed calculations of the energy band structures of the three compounds. Owing to the delocalized 5f behavior of UGa{sub 3}, and also of UAl{sub 3}, we find that an itinerant, energy band approach explains the dHvA frequencies of antiferromagnetic UGa{sub 3} and paramagnetic UAl{sub 3} reasonably well. For UGa{sub 3} an unusual sensitivity of the magnetic moment to the magnetic structure and the lattice parameter occurs, providing evidence that UGa{sub 3} is an unique example of an itinerant uranium-based antiferromagnet. thinsp {copyright} {ital 1999} {ital The American Physical Society}
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-06-01
Publisher Place United States
Journal Physical Review, B: Condensed Matter
Volume Number 59
Issue Number 22


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