Probing the chiral domain structure and dynamics in SR2RUO4 with nanoscale Josephson junctions

Bahr, Daniel

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https://hdl.handle.net/2142/26013 Copy

Description

Title

Probing the chiral domain structure and dynamics in SR2RUO4 with nanoscale Josephson junctions

Author(s)

Bahr, Daniel

Issue Date

2011-08-25T22:08:54Z

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

Van Harlingen, Dale J.

Doctoral Committee Chair(s)

Bezryadin, Alexey

Committee Member(s)

• Van Harlingen, Dale J.
• Fradkin, Eduardo H.
• Chemla, Yann R.

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Sr2RuO4
• chiral domains
• Josephson Interferometry
• Josephson Junctions

Abstract

Previous work on Sr2RuO4 has shown that the superconducting state is unconventional with an order parameter symmetry of px ipy. Measurements using Josephson Interferometry have shown evidence for chiral order parameter domains on the order of 1 m in size. To further search for signatures of these domains we have fabricated Josephson junctions on clean Sr2RuO4 single crystals (Tc=1.5 K) ranging from 500 nm to 4 m wide. Using an applied magnetic eld, we modulated the critical current of the junctions to make phasesensitive measurements of the order parameter of the p-wave superconductor. We observed critical current characteristics consistent with single and multiple domains being present in the junctions. We also observed hysteresis e ects in the junctions similar to previous experimental and theoretical work. We explored eld cooling e ects in the junctions that showed possible domain wall movement along the face of the junction. We also observed switches in the critical current that are not described currently by known theory and could be an indication of vertically oriented domains. We found that our smallest (500 nm) junctions consistently showed characteristics consistent with single domain junctions and that our results are consistent with 1 u m domains.

Graduation Semester

2011-08

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http://hdl.handle.net/2142/26013

Copyright and License Information

Copyright 2011 Daniel Bahr

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