Fabrication and Characterization of 45o a-axis tilt grain boundary YBa2Cu3O7-x Josephson junctions and dc SQUIDs

YBa(2)Cu(3)O(7-x)., junctions and de SQUIDs have been realized by employing 45 degrees axis tilt grain boundaries through a fabrication procedure based on the biepitaxial technique, YBa(2)Cu(3)O(7-x)., grows mainly oriented (103) on SrTiO(3) and (001) on the MgO seed layer, A wide characterization of the tilt junctions and SQUID properties has been carried out. High values of the I(C)R(N) quality factor and of the magnetic flux-to-voltage transfer parameter have been obtained. The observed phenomenology confirms differences from the one typical of 45 degrees c-asis tilt grain boundary junctions and gives important information on the nature of the current steps appearing at finite voltages in the current-voltage characteristics. These devices could also have some impact on esperiments designed to study the symmetry of the order parameter, exploiting their microstructure and anisotropic properties. A maximum speed of Josephson vortices as calculated from the voltage step values, of the order of 2 10(6) m/sec is obtained, which encourages high frequency applications.