Superconductivity in uranium materials
Metallic uranium materials occupy an interesting niche that is intermediate between transition and f-electron materials. Uranium in different environments is able to span this entire range, with narrow d-bands replaced by f-bands when the U-U distances are close enough for direct f-orbital overlap (closer than the Hill spacing), and with localized f-electrons forming magnetically ordered materials in the other extreme of large U-U spacing. As the U-U spacing and, in compounds, the ligand atoms, change, an interesting continuum of physics develops connected with the changing f-character of the materials. Corresponding to changing U-U separation are large, but non-monotonic, changes of more than two orders of magnitude in the low-temperature electronic specific heat parameter /gamma/. This parameter is a measure of the electronic density of states at the Fermi level, and in the free-electron theory of metals as well as the Landau Fermi liquid, the magnetic susceptibility chi due to the conduction electrons is also proportional to the density of states at the Fermi level. It is useful to plot for various materials the measured /gamma/ versus the T /yields/ O K limiting chi to see how much the measured chi is present, so to speak, in /gamma/. The authors do this for most of the known uranium superconductors. The solid line plotted there is the free-electron expression relating /gamma/ and chi. For materials with anisotropic susceptibility, the horizontal span of values corresponds to the range of chi values.
- Research Organization:
- Los Alamos National Lab., NM (USA); Laboratorium fur Festkorperphysik, ETH-Honggerborg, Zurich (CH)
- OSTI ID:
- 5846568
- Journal Information:
- Int. J. Mod. Phys. B; (United States), Vol. 3:4
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
SUPERCONDUCTIVITY
CALCULATION METHODS
URANIUM
ANISOTROPY
BERYLLIUM ALLOYS
BORON
COUPLING
ELECTRON DENSITY
ELECTRON-HOLE COUPLING
ELECTRONS
ENTROPY
HOLES
IMPURITIES
LOW TEMPERATURE
MAGNETIC SUSCEPTIBILITY
ORBITAL MOMENTUM OPERATORS
PARAMETRIC ANALYSIS
PHASE TRANSFORMATIONS
SOLID-STATE PLASMA
SPECIFIC HEAT
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ACTINIDE ALLOYS
ACTINIDES
ALLOYS
ANGULAR MOMENTUM OPERATORS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
LEPTONS
MAGNETIC PROPERTIES
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METALS
PHYSICAL PROPERTIES
PLASMA
QUANTUM OPERATORS
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