The Resistive Transition of Inhomogeneous Superconductors : Effects of “Mild” Granularity, Dimensionality, Gaussian Fluctuations and Critical Behaviour

  • P. Peyral
  • C. Lebeau
  • J. Rosenblatt
  • A. Raboutou
Part of the NATO ASI Series book series (NSSB, volume 222)

Abstract

Early studies of granular superconducting films1,2 showed that as long as the electronic mean-free-path ℓ was limited by the grain size a, little or no effect on the superconducting properties could be observed, while the normal-state-resistivity ρN was metallic, that is, dρN/dT > 0. Only when the apparent ℓ < a and dρN/dT < 0, indicating that insulating tunnelling barriers developed between grains, the critical temperature decreased and the resistive transition broadened dramatically1. We have shown that this broadening could be described in the case of weakly coupled grains with a ≫ ξ(T) (the Ginzburg-Landau coherence length) as a double transition3:the grains first become individually superconducting at a temperature Tcs and then the complex vectors representing the superconducting order parameter in each grain reach a coherent state when they become phase-ordered in the complex plane at a temperature Tc < Tcs. This is just the analogue of a paramagnetic-ferromagnetic XY phase transition4, where the phase- dependent intergranular coupling energy J ≃ kBTc plays the role of the exchange integral. Granularity becomes relevant in the superconducting state when J < Ec, the single-grain condensation energy in the normal state, when ρN ≫ ρGN, where ρb and ρGN are the barrier and grain contributions to ρN = ρb + ρGN.

Keywords

Epoxy Coherence 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    G. Deutscher, H. Fenichel, M. Gershenson, E. Grünbaum and Z. Ovadyahu, J. Low Temp. Phys. 10: 231 (1973).Google Scholar
  2. 2.
    B. Abeles and J.J. Hanak, Phys. Lett. 34A: 165 (1971).Google Scholar
  3. 3.
    P. Pellan, G. Dousselin, H. Cortès and J. Rosenblatt, Sol. State Comm. 11: 427 (1972).Google Scholar
  4. 4.
    J. Rosenblatt, A. Raboutou and P. Pellan, in “Low Temperature Physics LT14”, Vol.2, page 361, M. Krusius and M. Vuorio, ed. American Elsevier, New York (1975).Google Scholar
  5. 5.
    V. Ambegaokar and A. Baratoff, Phys. Rev. Lett. 10: 486 (1963).Google Scholar
  6. 6.
    L.G. Azlamazov and A.I. Larkin, Fiz. Tverd. Tela. 10:1104(1968) (Engl. transi. Sov. Phys. Sol. State 10:875(1968)) and Phys. Lett. 26A: 238 (1968).Google Scholar
  7. 7.
    W.E. Lawrence and S. Doniach in “Low Temperature Physics LT12”, page 361, E. Kanda, ed., Keigaku, Tokyo (1970).Google Scholar
  8. 8.
    P.P. Freitas, C.C. Tsuei and T.S. Plaskett, Phys. Rev. B36: 388 (1987);Google Scholar
  9. B. Oh, K. Char, A.D. Kent, M. Naito, M.R. Beasley, T.H. Geballe, R.H. Hammond, A. Kapitulnik and J.M. Graybeal, Phys. Rev. B37: 7861 (1988);Google Scholar
  10. Y. Matsuda, T. Hirai and S. Komiyama, Sol. State Comm. 68: 103 (1988).Google Scholar
  11. 9.
    J. Kirtley, Y. Imry and P.K. Hansma, J. Low Temp. Phys. 17: 247 (1974).Google Scholar
  12. 10.
    R.E. Glover III, Chapter 7, in “Progress in Low Temperature Physics VI”, C.J. Gorter ed., North-Holland, Amsterdam (1970).Google Scholar
  13. 11.
    C. Lebeau, J. Rosenblatt, A. Raboutou and P. Peyral, Europhys. Lett., 1: 313 (1986)Google Scholar
  14. P. Peyral, A. Raboutou, C. Lebeau and J. Rosenblatt, J. Phys. C: Sol. State Phys. 20: L155 (1987).Google Scholar

Copyright information

© Springer Science+Business Media New York 1990

Authors and Affiliations

  • P. Peyral
    • 1
  • C. Lebeau
    • 1
  • J. Rosenblatt
    • 1
  • A. Raboutou
    • 1
  1. 1.Laboratoire de Physique des SolidesURA 786 au CNRS INSARennes CedexFrance

Personalised recommendations