A Novel Method to Detect Oxygen Vacancies in the Grain Boundaries of High-Tc Superconductors

ORAL

Abstract

A new diagnostic method is introduced (pressure-induced $J_{c}$ relaxation) which is capable of detecting oxygen vacancies in the grain boundaries of oxide superconductors. A series of bicrystalline rings of YBa$_{2}$Cu$_{3}$O$_{x}$ containing single [001]-tilt grain boundaries with mismatch angles from 0 to 31 degrees are studied. Even for samples with nearly optimal doping in the bulk, a significant oxygen deficiency in the grain boundary region is revealed. In addition, compressing the grain boundary region is found to lead to a considerable enhancement of the critical current density $J_{c}$.

*Research at Washington University supported by NSF grant DMR-0404505 and that at the Argonne National Labs by the U.S. Department of Energy, Basic Energy Sciences-Materials Sciences, under contract W-31-109-ENG-38.

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Authors

  • Takahiro Tomita

  • James S. Schilling

    • Department of Physics, Washington University, St. Louis, MO

  • Lihua Chen

  • Boyd W. Veal

    • Argonne National Laboratory

  • H. Claus

    • Materials Science Division, Argonne National Labs