Title :
New techniques for fabricating step-edge junctions for high-T/sub c/ SQUIDs on MgO substrates
Author :
Foley, C.P. ; Dart, D.L. ; Katsaros, A. ; Savvides, N. ; James, M. ; Macfarlane, J.C. ; Scheepers, N. ; Sloggett, G.J.
Author_Institution :
CSIRO Div. of Appl. Phys. Lab., Sydney, NSW, Australia
fDate :
3/1/1993 12:00:00 AM
Abstract :
The authors describe two methods used to produce step-edge junctions on MgO substrates suitable for superconducting quantum interference devices (SQUIDs). In both processes a titanium mask has been used to produce a straight, well-defined step which assists in minimizing the occurrence of multiple junctions. They describe two ion-milling processes which produce differently connected step-edge junctions as indicated by scanning electron microscope (SEM) micrographs, and I-V and I/sub C/-B characteristics. Predictable relationships between the ratio of the film thickness to step height and the junction critical-current density are demonstrated; these enable the creation of step-edge junctions with appropriate values of I/sub C/ for particular SQUID designs.<>
Keywords :
Josephson effect; SQUIDs; barium compounds; critical current density (superconductivity); grain boundaries; high-temperature superconductors; scanning electron microscope examination of materials; superconducting thin films; yttrium compounds; 77 K; I-V characteristics; Josephson junction; MgO substrates; SEM micrographs; SQUID designs; Ti mask; YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin films; critical-current density; film thickness; grain boundary junction; high temperature superconductor; ion-milling processes; scanning electron microscope; step height; step-edge junctions; superconducting quantum interference devices; weak links; Critical current; Etching; Grain boundaries; Ion beams; Josephson junctions; Milling machines; Radio frequency; SQUIDs; Substrates; Superconducting films;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
