Measurement of the current-phase relation of superconductor/ferromagnet/ superconductor π Josephson junctions

S. M. Frolov, D. J. Van Harlingen, V. A. Oboznov, V. V. Bolginov, V. V. Ryazanov

Research output: Contribution to journalArticle

Abstract

We present measurements of the current-phase relation (CPR) of superconductor-ferromagnet-superconductor (SFS) Josephson junctions as a function of temperature. The CPR is determined by incorporating the junction into a superconducting loop coupled to a dc SQUID, allowing measurement of the junction phase difference. We find that the critical current of Nb-Cu 0.47Ni0.53-Nb Josephson junctions with barrier thickness ∼22 nm changes sign at T<Tπ∼2-4 K, indicating that the junction becomes a π Josephson junction. We find no evidence for second-order Josephson tunneling near Tπ in the CPR predicted by several theories.

Original languageEnglish (US)
Article number144505
Pages (from-to)144505-1-144505-5
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume70
Issue number14
DOIs
StatePublished - Oct 1 2004

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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