Superstructures and superconductivity

Journal Article · Fri Apr 02 00:00:00 EST 1993 · Science (Washington, D.C.); (United States)

DOI:https://doi.org/10.1126/science.260.5104.38· OSTI ID:6400334

Fisk, Z; Aeppli, G

Heavy fermion materials - so named because their conduction electrons behave as though they had extra mass - are like the cuprates in that they exhibit unusual superconducting properties. By the time the cuprates had been discovered, a good understanding of these materials was in hand. Unlike theories of high-[Tc] superconductivity, however, ideas about heavy fermions have not been the subject of great controversy. Thus, most of the effort in this backwater of condensed matter physics has focused on certain details of the behavior of one particularly well-studied compounds, UPt[sub 3]. The cause for sustained interest was that the process of developing ever more elaborate explanations for ever more elaborate experiments did not seem to converage. A recent paper by Midgley et al. reporting modulations in the crystal lattice of UPt[sub 3] suggests that theory and experiment might finally converge in a way that, while it does not threaten the broad understanding of heavy fermion systems, involves a degree of freedom ignored until now even in the face of past experience with elemental metallic uranium. Their transmission electron micrograph evidence for the existence of an incommensurate lattice modulation in UPt[sub 3] implicates this modulation as a probable source of the double superconducting transitions. Remarkably, the superconducting and magnetic coherence lengths, and the now discovered modulation period, are all of the same magnitude. For some time people have felt that stacking faults might be relevant to the properties of UPt[sub 3], but these new results are distinct from this. What Midgley et al. suggest is that the complicated superconducting phase diagram of UPt[sub 3] derives from the internal strain field caused by the modulation, and that this strain field lifts the degeneracy associated with unconventional pairing.

• OSTI ID: 6400334
• Journal Information: Science (Washington, D.C.); (United States), Vol. 260:5104; ISSN 0036-8075
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
PLATINUM ALLOYS
SUPERCONDUCTIVITY
TYPE-II SUPERCONDUCTORS
CRYSTAL STRUCTURE
URANIUM ALLOYS
ANISOTROPY
ELECTRONS
INTERMETALLIC COMPOUNDS
MAGNETIC MOMENTS
MASS
ACTINIDE ALLOYS
ALLOYS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
SUPERCONDUCTORS
360107* - Metals & Alloys- Superconducting Properties- (1992-)