Title :
Development of ramp-edge SNS junctions using highly stable normal-metal barrier materials
Author :
Jia, Q.X. ; Fan, Y. ; Kwon, C. ; Mombourquette, C. ; Reagor, D. ; Cantor, R. ; Zhou, J.P. ; Gim, Y. ; Jones, C. ; McDevitt, J.T. ; Goodenough, J.B.
Author_Institution :
Supercond. Technol. Center, Los Alamos Nat. Lab., NM, USA
fDate :
6/1/1999 12:00:00 AM
Abstract :
By using a cation-modified and corrosion-resistant compound of (Pr/sub y/Gd/sub 0.6-y/)Ca/sub 0.4/Ba/sub 1.6/La/sub 0.4/Cu/sub 3/O/sub 7/ (y=0.4, 0.5, and 0.6) as normal-metal barrier materials, high-temperature superconducting Josephson junctions have been fabricated in a ramp-edge superconductor/normal-metal/superconductor (SNS) configuration. We have tuned the Pr substitution level in order to achieve the optimal electrical resistivity of the barrier layer for high-performance SNS junctions. The junctions fabricated with these normal-metal barriers show well-defined RSJ-like current vs voltage characteristics at liquid-nitrogen temperature. The junction performance is mainly controlled by the N-layer instead of the interface. We have also fabricated dc superconducting quantum interference devices based on ramp-edge SNS technology with these normal-metal barriers. The ratio of peak-to-peak voltage modulation of the superconducting quantum interference devices to the I/sub c/R/sub n/ product is more than 30%.
Keywords :
Josephson effect; SQUIDs; barium compounds; calcium compounds; gadolinium compounds; high-temperature superconductors; lanthanum compounds; praseodymium compounds; superconductor-normal-superconductor devices; (Pr/sub y/Gd/sub 0.6-y/)Ca/sub 0.4/Ba/sub 1.6/La/sub 0.4/Cu/sub 3/O/sub 7/; (PrGd)/sub 0.6/Ca/sub 0.4/Ba/sub 1.6/La/sub 0.4/Cu/sub 3/O/sub 7/; DC SQUID; Josephson junction; RSJ model; current-voltage characteristics; electrical resistivity; high temperature superconductor; normal metal barrier; ramp-edge SNS junction; Chemical technology; Electrodes; High temperature superconductors; Josephson junctions; SQUIDs; Superconducting devices; Superconducting epitaxial layers; Superconducting materials; Voltage; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
