Strain effects in high temperature superconductors investigated with magneto-optical imaging

D. C. Van der Laan, H. J.N. Van Eck, B. Ten Haken, H. H.J. Ten Kate, J. Schwartz

Research output: Contribution to journalConference article

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Abstract

In order to determine the influence of intermediate deformation steps on the mechanical behavior of Bi-based tapes, the effect of longitudinal applied strain is investigated by means of magneto-optical imaging. The strain is applied in a helium flow-cryostat. Cracks appear soon after the critical current in Bi-based tapes is degraded. All filaments form multiple cracks that grow into tape-wide cracks, running from one filament to the next. The crack location is not caused by stress concentrations in the matrix, but by the mechanically weak colony boundaries. Because of the absence of intermediate rolling steps in the production of Bi2Sr2CaCu2Ox tapes, a different crack structure is observed compared to Bi2Sr2Ca2Cu2Ox tapes. The relation between the critical current and the formation of cracks is studied. The degradation in critical current before the critical strain is reached may be caused by microcracks that remain undetected by magneto-optical imaging. The influence of strain on the microstructure of YBa2Cu3Ox coated conductors is also investigated with magneto-optical imaging. The formation of cracks is believed to be determined by the nickel substrate and related to the Ni-grain size.

Original languageEnglish (US)
Pages (from-to)3534-3539
Number of pages6
JournalIEEE Transactions on Applied Superconductivity
Volume13
Issue number2 III
DOIs
Publication statusPublished - Jun 1 2003
Event2002 Applied Superconductivity Conference - Houston, TX, United States
Duration: Aug 4 2002Aug 9 2002

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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