Temperature dependence of the penetration depth in Sr2RuO4: evidence for nodes in the gap function

• Published in: Physical review letters Vol. 85; no. 22; pp. 4775 - 4778
• Main Authors: Bonalde, I, I, Yanoff, BD, Salamon, MB, Van Harlingen DJ, Chia, EM, Mao, ZQ, Maeno, Y
• Format: Journal Article
• Language: English
• Published: United States 27-11-2000
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.85.4775

We report measurements of the magnetic penetration depth in single crystals of Sr2RuO4 down to 0.04 K using a tunnel-diode based, self-inductive technique. We observe a power law temperature dependence below 0.8 K, with no sign of a second phase transition nor of a crossover predicted for a multiband superconductor. A power law dependence suggests that the gap function has nodes, inconsistent with candidate p-wave states. We argue that nonlocal effects, rather than impurity scattering, can explain the observed T2 dependence instead of the T-linear behavior expected for line nodes.