Positive curvature in the upper critical field of heavy fermion superconductors

L. E. De Long, D. Togliatti, G. W. Lehman, W. K. Kwok, G. W. Crabtree, K. G. Vandervoort, D. G. Hinks

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


New data on the upper critical magnetic field of single crystals of URu2Si2 show distinct upward curvature for the field H in the tetragonal basal plane, but not for fields along the tetragonal axis. The data for H<5 T can be explained as a result of the coupling of a multi-component superconducting order parameter with the magnetization of a spin-density wave. Alternatively, an empirical model succesfully applied to UPt3 and U6Fe provides an excellent fit of Hc2(T) for URu2Si2 over the entire experimental temperature (0.4 K ≤T≤1.5 K) and field (0≤H≤ 8 T) ranges. Our results imply that unconventional superconductivity may occur over a wide interval of electronic effective mass ratio 20 < m*/me < 200.

Original languageEnglish
Pages (from-to)499-503
Number of pages5
JournalPhysica B: Condensed Matter
Issue number1-3
StatePublished - Apr 1990

Bibliographical note

Funding Information:
’ Also at the University of Illinois, Chicago, with partial support from Division of Educational Programs, Argonne National Laboratory. * Research supported by a grant from Research Corporation. ‘Research supported by the US Department of Energy, Basic Energy Sciences-Materials Science under Contract #W-31.109.ENG-38.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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