Title :
YBa2Cu3O7-δ/Au/Nb sandwich geometry SNS weak links on c-axis oriented YBa2 Cu 3O7-δ
Author :
Foote, M.C. ; Hunt, B.D. ; Bajuk, L.J.
Author_Institution :
Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA, USA
fDate :
3/1/1991 12:00:00 AM
Abstract :
Sandwich geometry superconductor/normal metal/superconductor structures have been fabricated on LaAlO3 and cubic zirconia with laser-ablated, c-axis-oriented YBa2Cu3 O7-δ base electrodes, 100-600 Å of Au, and Nb counter electrodes, all formed in situ without breaking vacuum. Junctions range in size from 5 to 50 μm on a side. Four probe I-V measurements at 4.2 K show RnA products as low as 6×10 -9 Ωcm2 and critical current densities up to 5.2 kA/cm2. AC Josephson steps were observed with the application of 10-GHz radiation. The temperature dependence of Jc and the observation of the AC Josephson effect suggest that true supercurrents are present and that they do indeed represent the characteristics of the YBa2Cu3O7-δ/Au/Nb structure. The best results were obtained when the devices were annealed at ~450°C in O2 for 30 min after Au deposition
Keywords :
barium compounds; critical current density (superconductivity); gold; high-temperature superconductors; niobium; superconducting junction devices; type II superconductors; yttrium compounds; 100 to 600 Å; 30 min; 450 degC; 5 to 50 micron; AC Josephson effect; I-V measurements; SNS weak links; YBa2Cu3O7-δ-Au-Nb; critical current densities; high temperature superconductors; sandwich geometry; superconductor-normal metal-superconductor; supercurrents; temperature dependence; type II superconductors; Critical current density; Current measurement; Density measurement; Electrodes; Geometrical optics; Gold; Niobium; Probes; Radiation detectors; Temperature dependence;
Journal_Title :
Magnetics, IEEE Transactions on
