YBCO Thin Film DC-SQUIDs with Step-edge Josephson Junctions

  • P. Seidel
  • F. Schmidl
  • H. Schneidwind
  • L. Dörrer
  • M. Darula


YBa2Cu3O7−x thin film DC-SQUIDs using step-edge Josephson junctions are prepared by laser ablation and sputtering on (100) SrTiO3 substrates. There is a strong dependence of critical current on the ratio of step height to film thickness. Ion beam etching of the contact region allows changes of parameters of the junctions thus giving possibilities to optimize the SQUID parameters. The properties of step-edge junction SQUIDs are discussed within the frame of a RCSJ model using arrays of junctions in series closed in a superconducting loop instead of single junctions. It is shown that the behaviour of such a network SQUID is different to the usual two junction SQUID. These differences like a hysteresis in the voltage-flux characteristics and an intrinsic telegraph-like noise show the limitations of step-edge junction SQUIDs.


Critical Current Josephson Junction Single Junction Superconducting Loop External Magnetic Flux 


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Copyright information

© Springer-Verlag Tokyo 1994

Authors and Affiliations

  • P. Seidel
    • 1
  • F. Schmidl
    • 1
  • H. Schneidwind
    • 1
  • L. Dörrer
    • 1
  • M. Darula
    • 1
    • 2
  1. 1.Institut für FestkörperphysikFriedrich-Schiller-Universität JenaJenaGermany
  2. 2.Institute of Electrical EngineeringSlovak Academy of SciencesBratislavaSlovak Republic

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