Electron Tunneling into Superconducting Bismuth-Copper Oxide Systems

  • Toshikazu Ekino
  • Jun Akimitsu


The energy gaps of the polycrystal1ine Bi-Sr-Ca-Cu-O and Bi-Sr-Cu-O superconductors have been measured by means of the point-contact tunneling technique. We find that the energy gaps at T=OK are 2Δ=76-81meV in Bi2Sr2Ca1Cu2Oy(Tc=76K), 91–100meV in Bi2Sr2Ca2Cu3Oy(Tc=105K) and 3.0–3.5meV in Bi2Sr2Cu1Oy (Tc=6.5K). Temperature variations of these energy gaps are also extracted. The ratios 2Δ/kTc are 11.6–12.4 for Bi2Sr2Ca1Cu2Oy, 10.0–11.0 for Bi2Sr2Ca2Cu3Oy, extremely larger than BCS value. 2Δ/kTc of Bi2Sr2Cu1Oy is 5.4–6.2, larger than those of the usual strong coupling superconductors. These results give the information about the difference of the pairing nature on the superconducting state between these materials which have multiple Cu02 layers or a single CuO2 layer between the SrO layers.


Superconducting State Electron Tunneling High Bias Region Cu02 Layer Copper Oxide System 
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. Maeda, Y. Tanaka, M. Fukutomi and T. Asano, Jpn. J. Appl. Phys. 27, L209(1988).ADSCrossRefGoogle Scholar
  2. 2.
    C. Michel, M. Herview, M.M. Borel, A. Gradin, F. Deslandes, J. Provost and B. Raveau, Z. Phys. B68, 421(1987).ADSCrossRefGoogle Scholar
  3. 3.
    J. Akimitsu, A. Yamazaki, H. Sawa and H. Fujiki, Jpn. J. Appl. Phys. 26, L2080(1987).ADSCrossRefGoogle Scholar
  4. 4.
    P.W. Anderson, Science 235, 1196(1987).ADSCrossRefGoogle Scholar
  5. 5.
    CM. Varma, S. Schmidt-Rink and E. Abrahams, Solid State Commun. 62, 681(1987).ADSCrossRefGoogle Scholar
  6. 6.
    See for example, Novel Superconductivity, edited by S. A. Wolf and V. Z. Kresin (Plenum, New York, 1987).Google Scholar
  7. 7.
    M. Naito, D.P.E. Smith, M.D. Kirk, B. Oh, M.R. Hahn, K. Char, D.B. Mitzi, J.Z. Sun, D.J. Webb, M.R. Beasley, O. Fischer, T.H. Geballe, R.H. Hammomd, A. Kapitulnik and C.F. Quate, Phys. Rev. B35, 7228(1987).ADSGoogle Scholar
  8. 8.
    I. Iguchi, H. Watanabe, Y. Kasai, T. Mochiku, A. Sugishita and E. Yamaka, Jpn. J. Appl. Phys. 26, L645(1987).ADSCrossRefGoogle Scholar
  9. 9.
    T. Ekino, J. Akimitsu, Y. Mastuda and M. Sato, Solid State Commun. 63, 41(1987).ADSCrossRefGoogle Scholar
  10. 10.
    R.C. Dynes, V. Narayanamurti and J.P. Garno, Phys. Rev. Lett. 41, 1509(1978).ADSCrossRefGoogle Scholar
  11. 11.
    T. Ekino, J. Akimitsu, M. Sato and S. Hosoya, Solid State Commun. 62, 535(1987).ADSCrossRefGoogle Scholar
  12. 12.
    T. Ekino and J. Akimitsu, Jpn. J. Appl. Phys. 26, L452(I987).ADSCrossRefGoogle Scholar

Copyright information

© Springer Japan 1989

Authors and Affiliations

  • Toshikazu Ekino
    • 1
  • Jun Akimitsu
    • 1
  1. 1.Department of PhysicsAoyama-Gakuin UniversitySetagaya-ku, Tokyo, 157Japan

Personalised recommendations