Title :
Hysteretic YBa/sub 2/Cu/sub 3/O/sub 7- delta /-Au- YBa/sub 2/Cu/sub 3/O/sub 7-/ delta proximity effect Josephson junctions
Author :
Kirk, K.J. ; Donaldson, G.B. ; Bowman, R.M. ; Cochran, A. ; Edwards, J.A. ; Chew, N.G. ; Satchell, J.S.
Author_Institution :
Dept. of Phys. & Appl. Phys., Strathclyde Univ., Glasgow, UK
fDate :
3/1/1993 12:00:00 AM
Abstract :
The superconducting proximity effect can be used to produce Josephson junctions in high-temperature superconducting structures with a normal conducting carrier. The authors describe work on edge-microbridge junctions made by defining 10-30- mu m-wide Au bridges to link the upper and lower layers of a YBa/sub 2/Cu/sub 3/O/sub 7- delta /Y/sub 2/O/sub 3/-YBa/sub 2/Cu/sub 3/O/sub 7- delta / trilayer. The structures are patterned by photolithography and ion milling from multilayers grown in situ by electron-beam evaporation. The best junctions operate up to around 20 K, exhibit hysteresis in their current-voltage characteristics, and have an I/sub c/R/sub N/ (critical-current normal-resistance product) greater than 200 mu V at 4.2 K. With a 400-nm-long microbridge, the maximum junction T/sub c/ observed was 25 K, and the largest I/sub c/R/sub N/ product at 4.2 K was 400 mu V.<>
Keywords :
Josephson effect; X-ray diffraction examination of materials; barium compounds; critical current density (superconductivity); electron beam deposition; high-temperature superconductors; photolithography; proximity effect; superconducting junction devices; superconducting thin films; yttrium compounds; 10 to 30 micron; 25 K; 4.2 K; 400 muV; 400 nm; Au bridges; SNS junction; X-ray diffraction; YBa/sub 2/Cu/sub 3/O/sub 7- delta /-Y/sub 2/O/sub 3/-YBa/sub 2/Cu/sub 3/O/sub 7- delta / hysteretic junction; critical-current normal-resistance product; current-voltage characteristics; edge-microbridge junctions; electron-beam evaporation; high-temperature superconducting structures; hysteresis; ion milling; normal conducting carrier; patterning; photolithography; proximity effect Josephson junctions; Bridges; Gold; High temperature superconductors; Hysteresis; Josephson junctions; Lithography; Milling; Nonhomogeneous media; Proximity effect; Superconducting epitaxial layers;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
