Electron beam irradiation was utilized to fabricate planar Josephson junctions in Y1Ba2Cu3O7 thin films. After the micron-size bridges had been fabricated by way of standard optical lithography, they were modified using a well focused nanometer STEM probe with beam energy within the range of 80 - 120 keV. Modified junctions exhibit a two-step normal/superconductor transition. We attribute the lower transition temperature, which is of the order of 77 K, to the transition of the damaged region. Shapiro steps under applied microwave radiation of the frequency 10-15 GHz, as well as oscillation of the critical current in a magnetic field were observed up to 70 K. A comparison with the RSJ model is made and a possible damage mechanism is discussed.
|Number of pages||4|
|Journal||Physica C: Superconductivity and its applications|
|State||Published - 20 Apr 1993|