Heavy fermions in Kondo lattice compounds (invited)

Journal Article · Mon Apr 15 00:00:00 EST 1985 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.335212· OSTI ID:5785033

Steglich, F; Rauchschwalbe, U; Gottwick, U; Mayer, H M; Sparn, G; Grewe, N; Poppe, U; Franse, J J.M.

Even in the absence of both magnetic order and superconductivity, Ce-based Kondo lattice systems show distinct anomalies in the low-temperature specific heat and thermopower. These features can be understood, in the frame of a microscopic treatment of the asymmetric Anderson model, by taking into account the periodicity of the Ce sites. A substantial variation in the observed phenomena between CeAl/sub 3/ and normal (n) state CeCu/sub 2/Si/sub 2/ on the one hand as well as CeRu/sub 2/Si/sub 2/ and CeCu/sub 6/ on the other highlight the importance of realistic band structure calculations for the quasiparticles (''heavy fermions'') in these different compounds. The temperature dependence of the upper critical magnetic field B/sub c//sub 2/(T) for the heavy-fermion superconductor CeCu/sub 2/Si/sub 2/ (T/sub c/approx. =0.6 K) shows a flat maximum at approx.0.2 T/sub c/, which is ascribed to coherence-derived structure in the n-state quasiparticle density of states. A dc Josephson effect with a critical pair current of ordinary size is observed for the first time on a weak link between CeCu/sub 2/Si/sub 2/ and Al. This proves that CeCu/sub 2/Si/sub 2/ is a superconductor with dominant spin-singlet pairing. No Josephson effect can be found, however, between heavy-fermion superconducting UPt/sub 3/ and Al, Nb, or UPt/sub 3/ as counterelectrodes, in accord with a possible anisotropic (L > or = 1, S = 0 or 1) pairing in UPt/sub 3/.

• Research Organization: Institut fuer Festkoerperphysik, Technische Hochschule Darmstadt, D-6100 Darmstadt, Federal Republic of Germany
• OSTI ID: 5785033
• Journal Information: J. Appl. Phys.; (United States), Vol. 57:8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CERIUM ALLOYS
CRYSTAL MODELS
KONDO EFFECT
SUPERCONDUCTIVITY
THERMOELECTRICITY
RUTHENIUM ALLOYS
PLATINUM ALLOYS
URANIUM ALLOYS
ALUMINIUM ALLOYS
COPPER ALLOYS
SILICON ALLOYS
CRITICAL FIELD
JOSEPHSON JUNCTIONS
SPECIFIC HEAT
ACTINIDE ALLOYS
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRICITY
JUNCTIONS
MAGNETIC FIELDS
MATHEMATICAL MODELS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE EARTH ALLOYS
SUPERCONDUCTING JUNCTIONS
THERMODYNAMIC PROPERTIES
360104* - Metals & Alloys- Physical Properties
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Electronic
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