Evaluation of vortex pinning across low angle grain boundary in YBa_2Cu_3O_7 film

摘要

Vortex pinning potential across a 5° tilt low angle grain boundary (GB) was evaluated by measuring angular dependences of critical current density in a bicrystal YBa_2Cu_3O_7 film under the variable Lorentz force configuration. Trapping angles of the GB depend on directions in the GB plane (70°-80° and 15°-45° for the c-axis direction and the ab plane one, respectively), due to anisotropic pinning of GB dislocations. Pinning potential across a GB is as large as that of heavy ion irradiated columnar defects, indicating that density and distribution of GBs should be controlled to improve vortex pinning in coated conductors.