Advertisement

Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Superconductivity and phase stability of Nb3Ge

  • 87 Accesses

  • 42 Citations

Abstract

The A-15 phase of chemically vapor-deposited Nb3Ge has been investigated by annealing techniques in the temperature range 700–1450°C and by irradiation with high-energy neutrons (E>1 MeV). By x-ray diffraction analysis the samples were found to contain about 55 wt % of the A-15 phase, 35 wt % of tetragonal Nb5Ge3, and minor amounts of NbO2, NbO, and hexagonal Nb5Ge3. The superconducting transition temperatureT c and lattice parametera 0 of the A-15 phase have been measured as a function of annealing temperature and neutron irradiation.T c for the unirradiated sample remained above 19 K for long-term anneals in the temperature range 700–1000°C but decreased rapidly above 1000°C, reaching a limiting value of about 6 K at 1250°C, compared to the as-deposited value of about 20 K. The decrease inT c was accompanied by an increase ina 0 and an increase in the amount of tetragonal Nb5Ge3 to about 50 wt %. The observed decrease inT c was irreversible in that subsequent annealing at 1100°C did not result in any increase inT c or decrease ina 0 . Large depressions inT c were also observed in a sample irradiated with high-energy neutrons. The sample having aT c of about 21 K was found to exhibit no superconductivity to 1.5 K after exposure to a fluence of ∼5×1019 n/cm2. An increase ina 0 was also found as a function of neutron irradiation. However, in this case the effects were reversible in thatT c anda 0 of the irradiated sample could be restored to close to their original values by annealing in the 800–900°C range. The results are discussed in terms of stability of the A-15 phase and the effect of site-exchange disorder and composition on the superconducting properties and lattice parameters. It is concluded that the stoichiometric composition is metastable and upon annealing transforms to a stable, Nb-rich A-15 phase containing about 83 at % Nb with aT c of ∼6 K accompanied by precipitation of tetragonal Nb5Ge3.

This is a preview of subscription content, log in to check access.

References

  1. 1.

    B. T. Matthias,Phys. Rev. 97, 74 (1955).

  2. 2.

    R. H. Willens, T. H. Geballe, A. C. Goss, J. P. Maita, A. Nenth, G. W. Hull, and R. R. Soden,Solid State Commun. 7, 837 (1969).

  3. 3.

    G. W. Webb, L. J. Vieland, R. E. Miller, and A. Wicklund,Solid State Commun. 9, 1769 (1971).

  4. 4.

    J. R. Gavaler,Appl. Phys. Lett. 23, 480 (1973); L. Testardi, J. H. Wernick, and W. A. Roger,Solid State Commun. 15, 1 (1974).

  5. 5.

    J. R. Gavaler, M. A. Janocko, and C. K. Jones,J. Appl. Phys. 45, 3009 (1974).

  6. 6.

    L. R. Testardi, R. L. Meek, J. M. Poate, W. A. Royer, A. R. Storm, and J. H. Wernick,Phys. Rev. 11, 4304 (1975).

  7. 7.

    Y. Tarutani, M. Kudo, and S. Taguchi, inProc. ICEC5 477, IPC Science and Technology Press (1974).

  8. 8.

    H. Lutz, H. Wiesmann, Y. A. Bashkirov, O. F. Kammerer, M. Strongin, G. Warren, J. Roche, and D. H. Douglass, inProc. Int. Conf. Low Lying Lattice Vibrational Modes and their Relationship to Superconductivity and Ferroelectricity, San Juan, Puerto Rico, December 1975.

  9. 9.

    L. R. Newkirk, F. A. Valencia, A. L. Giorgi, E. G. Sklarz, and T. C. Wallace,IEEE Trans. Mag. MAG 11-2, 221 (1975); L. R. Newkirk, F. A. Valencia, and T. C. Wallace, inProc. Fifth Int. Conf. Chemical Vapor Deposition, London, England, September 1975.

  10. 10.

    G. W. Roland and A. I. Braginski, ICMC-CEC, Kingston, Ontario, Canada, July 22–25, 1975.

  11. 11.

    J. J. Engelhardt and G. W. Webb,Solid State Commun., to be published.

  12. 12.

    B. T. Matthias, T. H. Geballe, R. H. Willens, E. Corenzwit, and G. W. Hull, Jr.,Phys. Rev. 139, A1501 (1965).

  13. 13.

    S. Geller,Acta Cryst. 9, 885 (1956).

  14. 14.

    G. R. Johnson and D. H. Douglass,J. Low Temp. Phys. 14, 565 (1974).

  15. 15.

    J. H. Carpenter,J. Phys. Chem. 67, 2141 (1963).

  16. 16.

    T. B. Reed, H. C. Gatos, W. J. LaFleur, and J. T. Rody, inMetallurgy of Advanced Electronic Materials, G. E. Brock, ed. (Interscience, 1963), p. 71.

  17. 17.

    D. Dew-Hughes,Cryogenics 1975 (August), 435.

  18. 18.

    N. E. Alekseevskii, N. U. Ageev, and V. F. Shamrai,Isv. Akad. Nauk SSR, Neorgan. Mat. 2, 2156 (1966).

  19. 19.

    A. R. Sweedler and D. E. Cox,Phys. Rev. B 12, 147 (1975).

  20. 20.

    J. B. Nelson and D. P. Riley,Proc. Phys. Soc. Lond. 57, 160 (1945).

  21. 21.

    G. R. Johnson and D. H. Douglass,J. Low Temp. Phys. 14, 575 (1974).

  22. 22.

    R. Bett,Cryogenics 14, 361 (1974).

  23. 23.

    A. R. Sweedler, D. G. Schweitzer, and G. W. Webb,Phys. Rev. Lett. 33, 168 (1974); A. R. Sweedler, D. E. Cox, D. G. Schweitzer, and G. W. Webb,IEE Trans. Magnetics MAG-2, 163 (1975); A. R. Sweedler, D. E. Cox, and L. Newkirk,J. Electronic Materials, to be published.

  24. 24.

    V. M. Pan, V. I. Latysheva, and E. A. Shishkin, inPhysics and Metallurgy of Superconductors, E. M. Savitski and V. V. Baron, eds. (Consultants Bureau, New York, 1970), p. 179.

  25. 25.

    A. Muller,Z. Naturforsch. 25A, 1659 (1970).

  26. 26.

    B. Besslin, G. Ischenko, S. Klaumunzer, P. Muller, H. Neumuller, K. Schnetz, and H. Adrian,Phys. Lett. 53A, 49 (1975).

  27. 27.

    J. M. Poate, L. R. Testardi, A. R. Storm, and W. M. Augustyniak,Phys. Rev. Lett. 35, 1290 (1975).

Download references

Author information

Additional information

This work was performed under the auspices of the U.S. Energy Research and Development Administration.

By acceptance of the article, the publisher and/or recipient acknowledges the U.S. Government's right to retain a nonexclusive, royalty-free license in and to any copyright concerning this paper.

On leave from Universidade Estadual de Campinas, Brazil, supported by Conselho Nacional de Pesquisas.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sweedler, A.R., Cox, D.E., Moehlecke, S. et al. Superconductivity and phase stability of Nb3Ge. J Low Temp Phys 24, 645–661 (1976). https://doi.org/10.1007/BF00657172

Download citation

Keywords

  • Precipitation
  • Depression
  • Hexagonal
  • Diffraction Analysis
  • Phase Stability