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Critical current of YBa(2)Cu(3)O(7-delta) low-angle grain boundaries.
J H Durrell1, M J Hogg, F Kahlmann
1University of Cambridge, Department of Materials Science and Metallurgy, Pembroke Street, Cambridge CB2 3QZ, United Kingdom. jhd25@cam.ac.uk
Physical Review Letters
|July 15, 2003
Summary
Measurements on Yttrium Barium Copper Oxide (YBa2Cu3O7-delta) thin films reveal critical current suppression when magnetic fields align with grain boundaries. A flux cutting model accurately describes this behavior in applied fields above 1 Tesla.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Superconductivity
Background:
- High-temperature superconductors like Yttrium Barium Copper Oxide (YBa2Cu3O7-delta) are crucial for advanced technologies.
- Understanding grain boundary behavior is key to optimizing superconducting properties in thin films.
Purpose of the Study:
- To investigate the angular dependence of transport critical current in YBa2Cu3O7-delta thin films.
- To analyze the effect of magnetic field orientation on single grain boundaries.
Main Methods:
- Transport critical current measurements were conducted on 5-degree [001]-tilt YBa2Cu3O7-delta single grain boundaries.
- The magnetic field was rotated in the plane of the film (phi) to study angular variations.
Main Results:
- Critical current (j(c)) is significantly suppressed when the magnetic field is within a specific angle (phi(k)) of the grain boundary.
- Above 1 Tesla, the grain boundary's behavior is dominated by the bulk grains outside this angular range.
- The observed angular dependence of j(c) in the suppressed region aligns with predictions from a flux cutting model.
Conclusions:
- The study demonstrates a clear angular dependence of critical current in YBa2Cu3O7-delta grain boundaries under magnetic fields.
- A flux cutting model effectively explains the suppression of critical current when the magnetic field is near the grain boundary plane.