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

Abstract

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° and 36.8°. The epitaxial, c‐axis oriented YBa2Cu3O7–x films were grown “in situ” by a high oxygen pressure dc 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 Ic(B) and the I–V curves under microwave irradiation showed weak‐link Josephson behavior. The dependence of Ic(B) shows an interference pattern due to the phase differences across the both junctions.