Heavy-fermion systems

Journal Article · Mon Oct 01 00:00:00 EDT 1984 · Rev. Mod. Phys.; (United States)

DOI:https://doi.org/10.1103/RevModPhys.56.755· OSTI ID:6122248

Stewart, G R

Since the discovery by Steglich et al. (1979) of superconductivity in the high-effective-mass (approx.200m/sub e/) electrons in CeCu/sub 2/Si/sub 2/, the search for and characterization of such ''heavy-fermion'' systems has been a rapidly growing field of study. The eight heavy-fermion systems known to date include superconductors (CeCu/sub 2/Si/sub 2/, UBe/sub 13/, UPt/sub 3/), magnets (NpBe/sub 13/, U/sub 2/Zn/sub 17/, UCd/sub 11/), and materials in which no ordering is observed (CeAl/sub 3/, CeCu/sub 6/). These f-electron materials have, in comparison to normal metals, enormous specific heat ..gamma.. values (450--1600 mJ/mol K/sup 2/), large values of the low-temperature magnetic susceptibility chi (8--50 x 10/sup -3/ emu/mol G), maxima in the resistivity at low temperatures with large rho/sub max/ values (100--200 ..mu cap omega.. cm), and unusual temperature dependences of their specific heats below 10 K. The three heavy-fermion superconductors show such unusual behavior that the possibility of p-wave pairing of the superconducting electrons, rather than the usual BCS s-wave pairing, cannot be ruled out. This paper reviews the experimental results to date, to serve both as a status report and as a starting point for future research. Several correlations between properties are pointed out, including the observation that a low value of the Wilson ratio (approx.chi/..gamma..) appears to correlate with the occurrence of superconductivity.

• Research Organization: Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545
• OSTI ID: 6122248
• Journal Information: Rev. Mod. Phys.; (United States), Vol. 56:4
• Country of Publication: United States
• Language: English

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SPECIFIC HEAT
CERIUM SILICIDES
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ELECTRICAL PROPERTIES
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MASS
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PLATINUM METAL ALLOYS
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