Temperature dependence of the penetration depth in the unconventional superconductor Sr2RuO4

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, λ(T), at very low temperatures. I report on measurements of λ(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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Yanoff, Brian David

Contributors dc:contributor

• Van Harlingen, Dale J.

• strontium ruthenate
• superconductors

Statement dc:rights

• ©2000 Brian David Yanoff

Language dc:language

en

Identifier

4328660

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/31304