Critical current density of YBa2Cu3O7-delta low-angle grain boundaries in self-field

A study has been perfomed on the superconducting critical current density J (c) flowing across low-angle grain boundaries in epitaxial thin films of YB a2Cu3O7-delta. The materials studied were dual grain boundary rings deposit ed on SrTiO3 and containing 2 degrees, 3 degrees, 5 degrees, and 7 degrees tilt boundaries. The current density in self-field was determined by magnet ometric methods at temperatures from 5 K to T-c. We conclude that at the hi gher temperatures of coated conductor applications, there is limited potent ial for improving J(c) by reducing the grain boundary angle below similar t o3 degrees. (C) 2001 American Institute of Physics.