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Journal of Low Temperature Physics

, Volume 34, Issue 5–6, pp 569–583 | Cite as

Preparation of Nb3Ge films by chemical transport reaction and their critical properties

  • Gin-ichiro Oya
  • E. J. Saur
Article

Niobium-germanium films have been deposited on sapphire substrates at 900 ‡C by a chemical transport reaction method. The highest superconducting transition onset temperature T C,on of 22.4 K is observed for a nearly stoichiometric Nb3Ge film with the A15-type structure (thickness ~ 93.5 Μm). Lattice constants for the Nb3Ge phase formed in the Nb-Ge films with both T C,on above 22 K and T C,midpoint above 21 K are found to extend from 5.143 to 5.153 ». Deposition rates for the obtained films are in the range of 2–10 Μm/min. Critical current densities for the Nb3Ge film with the highest T C,on value are observed to be relatively low (~ 103 A/cm2 at 19 K at self-field). This is due to the coarse grain structure of the film or the low density of effectual pinning centers in the film. Field variations of the pinning forces operating in this film in magnetic fields both parallel to the film surface and perpendicular to the film surface are found to follow closely b1/2(1\s-b)2, to which the pinning force for flux pinning at the surface of normal regions, such as grain boundaries, film surfaces, etc., is proportional, and where b is the reduced magnetic induction (B/BC2).A small increase in J C at low fields is caused by the presence of a small amount of the Nb5Ge3 phase in a Nb3Ge film, and seems attributable to additional flux pinning on Nb5Ge3-phase particles in the film.

Keywords

Sapphire Film Surface Onset Temperature Field Variation Critical Current Density 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    J. R. Gavaler, Appl. Phys. Lett. 23, 480 (1973).Google Scholar
  2. 2.
    L. R. Testardi, J. H. Wernick, and W. A. Royer, Solid State Comm. 15, 1 (1974).Google Scholar
  3. 3.
    J. R. Gavaler, M. A. Janocko, and C. K. Jones, J. Appl. Phys. 45, 3009 (1974).Google Scholar
  4. 4.
    L. R. Testardi, R. L. Meek, J. M. Poate, W. A. Royer, A. R. Storm, and J. H. Wernick, Phys. Rev. B 11, 4304 (1975).Google Scholar
  5. 5.
    Y. Tarutani, M. Kudo, and S. Taguchi, Proc. ICEC 5, 477 (1975).Google Scholar
  6. 6.
    L. R. Newkirk, F. A. Valencia, and T. C. Wallace, J. Electrochem. Soc. 123, 425 (1974).Google Scholar
  7. 7.
    A. I. Braginski and G. W. Roland, Appl. Phys. Lett. 25, 762 (1976).Google Scholar
  8. 8.
    J. J. Engelhardt and G. W. Webb, Solid State Comm. 18, 837 (1976).Google Scholar
  9. 9.
    S. Foner, E. J. McNiff Jr., J. R. Gavaler, and M. A. Janocko, Phys. Lett. 47A, 485 (1974).Google Scholar
  10. 10.
    J. R. Gavaler, M. A. Janocko, A. I. Braginski, and G. W. Roland, IEEE Trans. Mag. MAG-11, 192 (1975).Google Scholar
  11. 11.
    H. Braun and E. Saur, Proc. ICEC 6, K13 (1976).Google Scholar
  12. 12.
    A. I. Braginski, J. R. Gavaler, G. W. Roland, M. R. Daniel, M. A. Janocko, and A. T. Santhanam, IEEE Trans. Mag. MAG-13, 300 (1977).Google Scholar
  13. 13.
    H. F. Braun, E. N. Haeussler, and E. J. Saur, IEEE Trans. Mag. MAG-13, 327 (1977).Google Scholar
  14. 14.
    R. V. Carlson, R. J. Bartlett, L. R. Newkirk, and F. A. Valencia, IEEE Trans. Mag. MAG-13, 648 (1977).Google Scholar
  15. 15.
    B. T. Matthias, T. H. Geballe, R. H. Willens, E. Corenzwit, and G. W. Hull Jr., Phys. Rev. 139, A1501 (1965).Google Scholar
  16. 16.
    L. R. Newkirk, F. A. Valencia, A. L. Giorgi, E. G. Szklarz, and T. C. Wallace, IEEE Trans. Mag. MAG-11, 221 (1975).Google Scholar
  17. 17.
    D. A. Rogowski and R. Roy, J. Appl. Phys. 47, 4635 (1976).Google Scholar
  18. 18.
    J. J. Hanak, K. Strater, and G. W. Cullen, RCA Rev. 25, 342 (1964).Google Scholar
  19. 19.
    A. R. Sweedler, D. E. Cox, S. Moehlecke, R. H. Jones, L. R. Newkirk, and F. A. Valencia, J. Low Temp. Phys. 24, 645 (1976).Google Scholar
  20. 20.
    T. Claeson, J. Ivarsson, and S. E. Rasmussen, J. Appl. Phys. 48, 3998 (1977).Google Scholar
  21. 21.
    W. A. Fietz and W. W. Webb, Phys. Rev. 178, 657 (1969).Google Scholar
  22. 22.
    E. J. Kramer, J. Appl. Phys. 44, 1360 (1973).Google Scholar
  23. 23.
    D. Dew-Hughes, Phil. Mag. 30, 293 (1974).Google Scholar
  24. 24.
    M. Durieux; in Progress in Low Temperature Physics, Vol. 6, C. J. Gorter, ed. (1970), p. 405.Google Scholar
  25. 25.
    H. R. Hart, Jr. and P. S. Swartz, Phys. Rev. 156, 403 (1967).Google Scholar

Copyright information

© Plenum Publishing Corporation 1979

Authors and Affiliations

  • Gin-ichiro Oya
    • 1
  • E. J. Saur
    • 1
  1. 1.Institute of Applied Physics, University of GiessenGiessenWest Germany

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