Title :
Stacked series arrays of high-T/sub c/ trilayer Josephson junctions
Author :
Eckstein, J.N. ; Bozovic, I. ; Virshup, G.F. ; Ono, R.H. ; Benz, S.P.
Author_Institution :
E.L. Ginzton Res. Center, Varian Associates Inc., Palo Alto, CA, USA
fDate :
6/1/1995 12:00:00 AM
Abstract :
We report on the properties of stacked series arrays of trilayer Josephson junctions grown by atomic layer-by-layer molecular beam epitaxy. Trilayer Josephson junctions oriented so that the current travels in the c-axis direction have been described previously. Series arrays are made by placing more than one barrier layer in the Ba/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/-based, (2212), epitaxial structure. Single molecular layers of 2212 doped with Dy to reduce the local carrier concentration are used as barriers, and are placed very close to each other, e.g., separated by only a few molecular layers of the superconducting phase. Phase locking of a.c. Josephson currents has been observed. The critical current density of such junctions has been observed to be very uniform on wafers that are free of second phase defects, and operation up to 60 K has been obtained.<>
Keywords :
Josephson effect; barium compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; molecular beam epitaxial growth; strontium compounds; superconducting epitaxial layers; 60 K; AC Josephson currents; Ba/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/:Dy; Dy doped 2212 phase; atomic layer-by-layer molecular beam epitaxy; barrier layers; carrier concentration; critical current density; high-T/sub c/ trilayer Josephson junctions; phase locking; second phase defects; single molecular layers; stacked series arrays; Atomic beams; Atomic layer deposition; Conductivity; Electrons; Josephson junctions; Molecular beam epitaxial growth; Superconducting devices; Superconducting epitaxial layers; Superconducting materials; Superconducting transition temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
