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Evidence for unpinned magnetic flux vortices above theI ctransition in the 2223-phase high-T csuperconductor

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Abstract

A similarity in the dc voltage-current (V-I) curves for both direct and alternating transport currents is used to propose that unpinned flux vortices are generated above theI ctransition for dc transport currents, when Abrikosov flux vortices begin to penetrate the superconductor. Two methods can be used to give a dc voltage drop for an ac transport current: (1) if there is a slight dc offset voltage in the ac current which favors vortex loop collapse as in a traditional dcI ctest, or (2) if an asymmetric transverse magnetic field is present which favors vortex loop collapse for current in one direction over the reverse direction.

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References

  1. 1.

    W. J. Carr,AC Loss and Macroscopic Theory of Superconductors (Gordon and Breach, New York, 1983), pp. 34–35.

  2. 2.

    R. Kleineret al, Phys. Rev. Lett. 68, 2394 (1992).

  3. 3.

    H. A. Blackstead,J. Supercond. 5, 67 (1992).

  4. 4.

    L. Miu,Phys. Rev. B 45, 8142 (1992).

  5. 5.

    E. G. Zwartzet al., Can. J. Phys. 67, 614 (1989).

  6. 6.

    R. Meisels, S. Bungre, and A. D. Caplin,J. Less-Comman Met. 151, 83 (1989).

  7. 7.

    W. Neuhaus and K. Winzer,Cryogenics 32, 357 (1992).

  8. 8.

    B. Loberg, J. Niska, and P. Rubin,Appl. Supercond. 1, 1757 (1993).

  9. 9.

    L. F. Goodrich and S. L. Bray,Cryogenics 30, 667 (1990).

  10. 10.

    B. Loberg, J. Niska, P. Rubin, and R. Gustafsson,Cryogenics 33, 475 (1993).

  11. 11.

    R. Job and M. Rosenberg,Supercond. Sci. Technol. 5, 7 (1992).

  12. 12.

    F. B. Silsbee,J. Wash. Acad. Sci. 6, 597 (1916).

  13. 13.

    S. Zannella, L. Jansak, K. Salama, and V. Selvamanickam,Cryogenics 33, 31 (1993).

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Niska, J., Loberg, B. Evidence for unpinned magnetic flux vortices above theI ctransition in the 2223-phase high-T csuperconductor. J Supercond 6, 255–259 (1993). https://doi.org/10.1007/BF00626266

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Key words

  • Flux vortices
  • superconductors
  • transport critical currents
  • 2223 phase
  • 50-Hz ac currents