Imaging spontaneous currents in superconducting arrays of π-junctions

Nature Physics

Volumn 4, Issue 1, 2008, Pages 32-36

  Frolov, Sergey M ^a   Stoutimore, Micah J A ^a   Crane, Trevis A ^a   Van Harlingen, Dale J ^a   Oboznov, Vladimir A ^b   Ryazanov, Valery V ^b   Ruosi, Adele ^c   Granata, Carmine ^d   Russo, Maurizio ^d  

^a United States of America   (United States)

^b INSTITUTE OF SOLID STATE PHYSICS   (Russian Federation)

^c INFM   (Italy)

^d CNR   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

GROUND STATE; JOSEPHSON JUNCTION DEVICES; QUANTUM COMPUTERS; QUANTUM INTERFERENCE DEVICES; SQUIDS; SUPERCONDUCTING MATERIALS;

GROUND-STATE PHASE; LOWEST ENERGY STATE; PERSISTENT CURRENTS; SUPERCONDUCTING ARRAYS; SUPERCONDUCTING LOOPS; SUPERCONDUCTING NETWORKS; ZERO FIELD CURRENTS; ZERO MAGNETIC FIELDS;

X-Y MODEL;

EID: 37749043050     PISSN: 17452473     EISSN: 17452481     Source Type: Journal    
DOI: 10.1038/nphys780     Document Type: Article

References (24)

1. Josephson, B. D. Possible new effects in superconductive tunneling. Phys. Lett. 1, 251-253 (1962).
2. Bulaevskii, L. N., Kuzii, V. V. & Sobyanin, A. A Superconducting system with weak coupling to a current in the ground state. JETP Lett. 25, 290-294 (1977).
3. Ryazanov, V. V. et al. Coupling of two superconductors through a ferromagnet: evidence for a π-junction. Phys. Rev. Lett. 86, 2427-2430 (2001).
4. Baselmans, J. J. A., Morpurgo, A. F., van Wees, B. & Klapwijk, T. M. Reversing the direction of supercurrent in a controllable Josephson junction. Nature 397, 43-45 (1999).
5. vam Dam, J. A., Nazarov, Y. V., Bakkers, E. P. A. M., De Franceschi, S. & Kouwenhoven, L. P. Supercurrent reversal in quantum dots. Nature 442, 667-670 (2006).
6. Della Rocca, M. L., Aprili, M., Kontos, T., Gomez, A. & Spathis, P. Ferromagnetic 0-π junctions as dassical spins. Phys. Rev. Lett. 94, 197003 (2005).
7. Vu, L. N. & Van Harlingen, D. J. Design and implementation of a scanning SQUID microscope. IEEE Trans. Appl. Supercond. 3, 1918-1921 (1993).
8. Korshunov, S. E. Phase transitions in two-dimensional systems with continuous degeneracy. Phys.-Uspekhi 49, 225-262 (2006).
9. Leo, C. D. & Rotoli, G. Paramagnetic and diamagnetic states in two-dimensional Josephson-junction arrays. Phys. Rev. Lett. 89, 167001 (2002).
10. Ioffe, L. B., Geshkenbdn, V. B., Fdgelman, M. V., Fauchere, A. L. & Blatter, G. Environmentally decoupled sds-wave Josephson junctions for quantum computing. Nature 398, 679-681 (1999).
11. Fulde, P. & Ferrell, R. A. Superconductivity in a strong spin-exchange field. Phys. Rev. 135, A550-A563 (1964).
12. Larkin, A I. & Ovchinnikov, Y. N. Inhomogeneous state of superconductors. Sov. Phys. JETP 20, 762-769 (1965).
13. de Jong, M. J. & Beenaker, C. W. J. Andreev reflection in ferromagnet-super conductor junctions. Phys. Rev. Lett. 74, 1657 (1995).
14. Buzdin, A. I. Proximity effects in superconductor-ferromagnet heterostructures. Rev. Mod. Phys. 77, 935-976 (2005).
15. Oboznov, V. A., Bolginov, V. V., Feofanov, A. K., Ryazanov, V. V. & Buzdin, A. I. Thickness dependence of the Josephson ground states of superconductor-ferromagnet-super conductor junctions. Phys. Rev. Lett. 96, 197003 (2006).
16. Yamashita, T., Tanikawa, K., Takahashi, S. & Maekawa, S. Superconducting π qubit with a ferromagnetic Josephson junction. Phys. Rev. Lett. 95, 097001 (2005).
17. Ustinov, A. V. & Kaplunenko, V. K. Rapid single-flux quantum logic using π-shifters. J. Appl. Phys. 94, 5405-5407 (2003).
18. Fominov, Y. V., Golubov, A. A. & Kupriyanov, M. Y. Decoherence due to nodal quasiparticles in d-wave qubits. JETP Lett. 77, 587-591 (2003).
19. Weides, M. et al. High quality ferromagnetic 0 and π Josephson tunnel junctions. Appl. Phys. Lett. 89, 122511 (2006).
20. Hilgenkamp, H. et al. Ordering and manipulation of the magnetic moments in large-scale superconducting π-loop arrays. Nature 442, 50-53 (2003).
21. x2-y2 symmetry. Rev. Mod. Phys. 67, 515-535 (1995).
22. Frolov, S. M., Van Harlingen, D. J., Oboznov, V. A., Bolginov, V. V. & Ryazanov, V. V. Measurement of the current-phase relation of superconductor/ferromagnet/superconductor π Josephson junctions. Phys. Rev. B 70, 144505 (2004).
23. Ryazanov, V. V., Oboznov, V. A., Veretennikov, A. V. & Rusanov, A. Y. Intrinsically frustrated superconducting array of superconductor-ferromagnet- superconductor π junctions. Phys. Rev. B 65, 020501 (2001).
24. Frolov, S. M., Van Harlingen, D. J., Bolginov, V. V., Oboznov, V. A. & Ryazanov, V. V. Josephson interferometry and Shapiro step measurements of superconductor-ferromagnet-superconductor 0-π junctions. Phys. Rev. B 74, 020503 (2006).