Journal of Low Temperature Physics

, Volume 66, Issue 3–4, pp 191–208 | Cite as

Anisotropy effects in tantalum, niobium, and vanadium down to the millikelvin temperature range

  • F. M. Sauerzopf
  • E. Moser
  • H. W. Weber
  • F. A. Schmidt


Experiments on the transition fields to the normal conducting state were made on single crystals of Ta, Nb, and V in the temperature range between 40 mK and the transition temperature. In tantalum results are presented on the thermodynamic quantitiesTc, μ0Hc(T),D(t), and γ in the clean limit and as a function of impurity concentration at low impurity levels (<0.15 at %). Special attention is paid to the phase transition between type I and type II superconductivity, which occurs at a certain conversion temperatureT*<Tc in materials with κ(Tc)<1/√2. This transition is found to be strongly anisotropic because of theHc2 anisotropy effect appearing in the type II superconducting state. It is shown that atT=0 no signs of type II superconductivity will appear for κ(Tc)⩽0.44, whereas type II superconductivity will be found in every crystal direction for κ(Tc)⩾0.50. The analysis ofHc2 anisotropy in Ta in terms of cubic harmonic functions demonstrates that the first anisotropic expansion coefficienta4 remains finite atT*, whereas the second,a6, vanishes when type II superconductivity disappears. No significant values of any higher order coefficient could be detected in Ta. For Nb and V the temperature dependence of the anisotropy coefficientsa4,a6,a8, anda10 was established in the entire temperature range. The diversity of results clearly indicates that different microscopic mechanisms contribute to the observedHc2 anisotropy effect in these materials.


Vanadium Niobium Harmonic Function Tantalum Superconducting State 
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.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    H. W. Weber, ed.,Anisotropy Effects in Superconductors (Plenum Press, New York, 1977).Google Scholar
  2. 2.
    P. C. Hohenberg and N. R. Werthamer,Phys. Rev. 153, 493 (1967).Google Scholar
  3. 3.
    H. Teichler,Phys. Stat. Sol. b 69, 501 (1975).Google Scholar
  4. 4.
    H. W. Pohl and H. Teichler,Phys. Stat. Sol. B 75, 205 (1976).Google Scholar
  5. 5.
    H. Teichler, inAnisotropy Effects in Superconductors, H. W. Weber, ed. (Plenum Press, New York, 1977), p. 7.Google Scholar
  6. 6.
    W. H. Butler,Phys. Rev. Lett. 44, 1516 (1980).Google Scholar
  7. 7.
    W. H. Butler, inSuperconductivity in d- and f-Band Metals, H. Suhl and M. B. Maple, eds. (Academic Press, New York, 1980), p. 443.Google Scholar
  8. 8.
    L. Niel, N. Giesinger, H. W. Weber, and E. Schachinger,Phys. Rev. B 32, 2976 (1985).Google Scholar
  9. 9.
    E. Seidl, H. W. Weber, and H. Teichler,J. Low Temp. Phys. 30, 273 (1978).Google Scholar
  10. 10.
    H. W. Weber, J. F. Sprona, and E. Seidl,Phys. Rev. Lett. 41, 1502 (1978).Google Scholar
  11. 11.
    J. F. Sporna, E. Seidl, and H. W. Weber,J. Low Temp. Phys. 37, 639 (1979).Google Scholar
  12. 12.
    E. Moser, E. Seidl, and H. W. Weber,J. Low Temp. Phys. 49, 585 (1982).Google Scholar
  13. 13.
    E. Moser, P. Hahn, E. Seidl, H. W. Weber, and E. Schachinger, inSuperconductivity in d- and f-Band Metals, W. Buckel and W. Weber, eds. (Kernforschungszentrum Karlsruhe, 1982), p. 519.Google Scholar
  14. 14.
    E. Moser, unpublished results (1982).Google Scholar
  15. 15.
    F. C. von der Lage and H. A. Bethe,Phys. Rev. 71, 612 (1947).Google Scholar
  16. 16.
    S. J. Williamson,Phys. Rev. B 2, 3545 (1970).Google Scholar
  17. 17.
    E. Fromm and E. Gebhardt,Gase und Kohlenstoff in Metallen (Springer-Verlag, Berlin, 1976).Google Scholar
  18. 18.
    O. N. Carlson, F. A. Schmidt, and D. G. Alexander,Met. Trans. 3, 1249 (1972).Google Scholar
  19. 19.
    F. M. Sauerzopf, E. Seidl, and H. W. Weber,J. Low Temp. Phys. 49, 249 (1982).Google Scholar
  20. 20.
    J. R. Clem,Ann. Phys. 40, 268 (1966).Google Scholar
  21. 21.
    D. Eckert and A. Junod, private communication.Google Scholar
  22. 22.
    B. B. Goodman,IBM J. Res. Dev. 6, 63 (1962).Google Scholar
  23. 23.
    L. P. Gor'kov,Sov. Phys. JETP 10, 998 (1960).Google Scholar
  24. 24.
    J. Auer and H. Ullmaier,Phys. Rev. B 7, 136 (1973).Google Scholar
  25. 25.
    E. Mayerhofer, F. M. Sauerzopf, and H. W. Weber, to be published.Google Scholar
  26. 26.
    U. Klein, private communication.Google Scholar
  27. 27.
    G. Eilenberger,Phys. Rev. 153, 584 (1967).Google Scholar
  28. 28.
    E. Helfand and N. R. Werthamer,Phys. Rev. Lett. 13, 686 (1964).Google Scholar
  29. 29.
    E. Helfand and N. R. Werthamer,Phys. Rev. 147, 288 (1966).Google Scholar
  30. 30.
    C. Laa, E. Seidl, and H. W. Weber, to be published.Google Scholar

Copyright information

© Plenum Publishing Corporation 1987

Authors and Affiliations

  • F. M. Sauerzopf
    • 1
  • E. Moser
    • 1
  • H. W. Weber
    • 1
  • F. A. Schmidt
    • 2
  1. 1.Atominstitut der Österreichischen UniversitätenViennaAustria
  2. 2.Materials Preparation CenterAmes LaboratoryAmes

Personalised recommendations