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Journal of Superconductivity

, Volume 7, Issue 2, pp 361–365 | Cite as

Two-gap structure in Yb(Y)Ba2Cu3O7−x single crystals

  • B. A. Aminov
  • M. A. Hein
  • G. Müller
  • H. Piel
  • D. Wehler
  • Ya. G. Ponomarev
  • K. Rosner
  • K. Winzer
XII. Tunneling Spectroscopy; Josephson Effect

Abstract

Tunneling effects in YbBa2Cu3O7−x (YbBCO) and YbBa2Cu3O7−x (YBCO) single crystals have been investigated using an improved technique of break junction preparation. A two-gap structure with BCS-like density of states has been observed. The value of the “large” gap is in the range of 24–28 meV for YBCO (T c =85–90 K) and 29–30 meV for YbBCO (T c =87–90 K). A variation of the value of the “small” gap between 0.5 and 11 meV has been detected, even for the same crystal. As a possible explanation, two-band superconductivity, surface properties, or strong gap anisotropy will be discussed.

Key words

Tunneling spectroscopy high-Tc superconductors 

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Copyright information

© Plenum Publishing Corporation 1994

Authors and Affiliations

  • B. A. Aminov
    • 1
  • M. A. Hein
    • 1
  • G. Müller
    • 1
  • H. Piel
    • 1
  • D. Wehler
    • 1
  • Ya. G. Ponomarev
    • 2
  • K. Rosner
    • 3
  • K. Winzer
    • 3
  1. 1.Fachbereich PhysikUniversität WuppertalGermany
  2. 2.Physics DepartmentMoscow State UniversityRussia
  3. 3.1 Physikalisches InstitutPhysikalisches Universität GöttingenGermany

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