Determining the superconducting order parameter of UPt3 with Josephson junction interferometry

Strand, Joel D.

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https://hdl.handle.net/2142/15582 Copy

Description

Title

Determining the superconducting order parameter of UPt3 with Josephson junction interferometry

Author(s)

Strand, Joel D.

Issue Date

2010-05-14T20:51:19Z

Director of Research (if dissertation) or Advisor (if thesis)

Van Harlingen, Dale J.

Doctoral Committee Chair(s)

Cooper, S. Lance

Committee Member(s)

• Van Harlingen, Dale J.
• Stone, Michael
• Pitts, Kevin T.

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• UPt3
• Josephson junctions
• unconventional superconductivity
• Josephson interferometry
• superconducting order parameter

Abstract

We report evidence for a complex low-temperature superconducting phase in UPt3 that breaks time-reversal symmetry and exhibits a phase shift of Pi in the superconducting order parameter between the a- and b-axes. We also report evidence for nodes in the amplitude of the superconducting energy gap in the high-temperature phase of UPt3. These nodes occur 45 degrees between the a- and b-axes and fill in as an out-of-phase energy gap component develops. This evidence supports the E2u representation of the superconducting order parameter. These measurements were taken by fabricating Pb-Cu-UPt3 Josephson junctions on polished and as-grown surfaces of UPt3 single crystals. By measuring the critical current through the junctions and varying the applied magnetic field, temperature, and angle of the junctions, we obtained information on the phase and magnitude of the superconducting order parameter.

Graduation Semester

2010-5

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http://hdl.handle.net/2142/15582

Copyright and License Information

Copyright 2010 Joel D. Strand

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