Critical current density of YBa2Cu3O7-δ 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 YBa2Cu3O7-delta. The materials studied were dual grain boundary rings deposited on SrTiO3 and containing 2 degrees, 3 degrees, 5 degrees, and 7 degrees tilt boundaries. The current density in self-field was determined by magnetometric methods at temperatures from 5 K to T-c. We conclude that at the higher temperatures of coated conductor applications, there is limited potential for improving J(c) by reducing the grain boundary angle below similar to3 degrees. (C) 2001 American Institute of Physics.