Temperature Dependence of the Penetration Depth in the Unconventional Superconductor Strontium Ruthenate

Yanoff, Brian David

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https://hdl.handle.net/2142/80684 Copy

Description

Title

Temperature Dependence of the Penetration Depth in the Unconventional Superconductor Strontium Ruthenate

Author(s)

Yanoff, Brian David

Issue Date

2000

Doctoral Committee Chair(s)

Van Harlingen, Dale J.

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Physics, Condensed Matter

Language

eng

Abstract

We have constructed a high resolution tunnel-diode oscillator based measurement system suitable for measuring the temperature dependence of the magnetic penetration depth of superconductors, lambda(T), at very low temperatures. I report on measurements of lambda(T) in high quality single crystals of the perovskite superconductor Sr2RuO4 down to 0.04 K. We observe quadratic temperature dependence at low temperatures. There is no sign of the crossover or second phase transition predicted for a multi-band superconductor. We argue that power law behavior is consistent with an energy gap with nodes, and discuss how the observed quadratic dependence can arise from several possible mechanisms. We propose that non-local effects may be more important in determining the temperature dependence than impurity scattering, and are sufficient to explain the deviation from the linear behavior expected for local superconductors with line nodes. These results are inconsistent with the candidate p-wave states predicted by leading theories.

Graduation Semester

2000

Type of Resource

text

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http://hdl.handle.net/2142/80684

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