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

doi:10.1103/PhysRevB.70.144505

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

Physics

Research output: Contribution to journal › Article › peer-review

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 _0.47Ni_0.53-Nb Josephson junctions with barrier thickness ∼22 nm changes sign at T<T_π∼2-4 K, indicating that the junction becomes a π Josephson junction. We find no evidence for second-order Josephson tunneling near T_π in the CPR predicted by several theories.

Original language	English (US)
Article number	144505
Pages (from-to)	144505-1-144505-5
Journal	Physical Review B - Condensed Matter and Materials Physics
Volume	70
Issue number	14
DOIs	https://doi.org/10.1103/PhysRevB.70.144505
State	Published - Oct 2004

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

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10.1103/PhysRevB.70.144505

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@article{eea7ef2d7a15453ea9c335c457a3ab60,

title = "Measurement of the current-phase relation of superconductor/ferromagnet/ superconductor π Josephson junctions",

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 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.",

author = "Frolov, {S. M.} and {Van Harlingen}, {D. J.} and Oboznov, {V. A.} and Bolginov, {V. V.} and Ryazanov, {V. V.}",

note = "Funding Information: We thank Marco Aprili and Alexander Golubov for useful discussions. Work supported by the National Science Foundation Grant No. EIA-01-21568 and by the U.S. Civilian Research and Development Foundation (CRDF) Grant No. RP1-2413-CG-02. We also acknowledge extensive use of the Microfabrication Facility of the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign.",

year = "2004",

month = oct,

doi = "10.1103/PhysRevB.70.144505",

language = "English (US)",

volume = "70",

pages = "144505--1--144505--5",

journal = "Physical Review B - Condensed Matter and Materials Physics",

issn = "0163-1829",

publisher = "American Institute of Physics",

number = "14",

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TY - JOUR

T1 - Measurement of the current-phase relation of superconductor/ferromagnet/ superconductor π Josephson junctions

AU - Frolov, S. M.

AU - Van Harlingen, D. J.

AU - Oboznov, V. A.

AU - Bolginov, V. V.

AU - Ryazanov, V. V.

N1 - Funding Information: We thank Marco Aprili and Alexander Golubov for useful discussions. Work supported by the National Science Foundation Grant No. EIA-01-21568 and by the U.S. Civilian Research and Development Foundation (CRDF) Grant No. RP1-2413-CG-02. We also acknowledge extensive use of the Microfabrication Facility of the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign.

PY - 2004/10

Y1 - 2004/10

N2 - 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 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.

AB - 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 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.

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U2 - 10.1103/PhysRevB.70.144505

DO - 10.1103/PhysRevB.70.144505

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JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

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ER -

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

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