Characterization of Josephson Junctions for the Elaboration of High-Tc SQUIDS

In this work we report the fabrication of superconductor loops, formed by an array of two Josephson junctions (JJ) in parallel. The JJ are based on YBa2Cu3O7-x epitaxial thin films deposited on SrTiO3 bicrystal substrates with misorientation angles of 24 degrees and 36.8 degrees. The epitaxial, c-axis oriented YBa2Cu3O7-x films were grown "in situ" by a high oxygen pressure de sputtering technique. For the fabrication of the superconductor loop a photolithographic method and a non-aqueous chemical etching were used. The superconducting properties of the superconductor loops were analyzed by measuring the current-voltage characteristics. The magnetic field dependence of the critical current I-c(B) and the I-V curves under microwave irradiation showed weak-link Josephson behavior. The dependence of I-c(B) shows an interference pattern due to the phase differences across the both junctions.