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

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

2361

Lastpage

2364

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;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233427

Filename

233427