Muon-spin rotation (μSR) study of the temperature dependence of the London penetration depth in copper oxide superconductors

• Published in: Physica. C, Superconductivity Superconductivity, 1991-12, Vol.185, p.1089-1090
• Main Authors: Keller, H., Kündig, W., Savić, I.M., Simmler, H., Stäuble-pümpin, B., Warden, M., Zech, D., Zimmermann, P., Kaldis, E., Karpinski, J., Rusiecki, S., Brewer, J.H., Riseman, T.M., Schneider, J.W., Maeno, Y., Rossel, C.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Properties of type I and type II superconductors; Superconductivity
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/0921-4534(91)91768-Y

A μSR study of the temperature dependence of the London penetration depth λ in sintered samples of YBa 2Cu 3O z (with various oxygen contents x), YBa 2Cu 4O 8 and Bi 2Sr 2CaCu 2O 8 is presented. It is found that the temperature behavior of λ of all these cuprate superconductors is consistent with conventional s-wave pairing. However, there are significant differences concerning the exact temperature dependence of λ in these materials. In YBa 2Cu 3O z with high x, the behavior of λ( T) is well described by the two-fluid model (strong coupling), whereas λ( T) in YBa 2Cu 3O z with low x, YBa 2Cu 4O 8 and Bi 2Sr 2CaCu 2O 8 is in better agreement with weak-coupling BCS theory. Possible reasons for the different temperature behavior of λ in these materials are discussed.