a-axis tilt grain boundaries for YBa2Cu3O7-x Superconducting Quantum Interferometers

Superconducting quantum interference devices (SQUIDs) have been fabricated using YBa2Cu3O72x @100# 45°-tilt grain-boundary Josephson junctions based on a controllable biepitaxial technique. These devices are characterized by large characteristic voltages, desirable magnetic-flux-to-voltage transfer parameters and low flux noise. An energy resolution of 1.6310230 J/Hz at liquid helium has been measured, which is the lowest value reported for biepitaxial SQUIDs. These junctions exhibit a phenomenology different from traditional @001# 45°-tilt biepitaxials probably due to the absence of p junctions. The performance of the presented SQUIDs demonstrates that significant improvements in the biepitaxial technique are possible, and the resulting devices have potential for applications