Heavy-fermion systems

Journal Article · Mon Oct 01 04:00:00 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), Journal Name: Rev. Mod. Phys.; (United States) Vol. 56:4; ISSN RMPHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTINIDE ALLOYS
ALLOYS
BCS THEORY
BERYLLIUM ALLOYS
CADMIUM A
CERIUM COMPOUNDS
CERIUM SILICIDES
COPPER COMPOUNDS
COPPER SILICIDES
CORRELATIONS
CRITICAL FIELD
DOCUMENT TYPES
EFFECTIVE MASS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETORESISTANCE
MASS
PHYSICAL PROPERTIES
PLATINUM ALLOYS
PLATINUM METAL ALLOYS
RARE EARTH COMPOUNDS
REVIEWS
SILICIDES
SILICON COMPOUNDS
SPECIFIC HEAT
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
URANIUM ALLOYS
ZINC ALLOYS