Feasibility of biepitaxial YBa2Cu3O7-x Josephson junctions for fundamental studies and potential circuit implementation

We present various concepts and experimental procedures to produce biepitaxial, YBa2Cu3O7-x grain-boundary Josephson junctions. The device properties have an interesting phenomenology, related in part to the possible influence of ``pi loops.'' The performance of our junctions and superconducting quantum interference devices indicates significant improvement in the biepitaxial technique. Further, we propose methods for fabricating circuits in which 0 and pi loops are controllably located on the same chip.