Fabrication and characterization of YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary Josephson junctions on [110] NdGaO/sub 3/ bicrystal and single-twin substrates

Author

Schulz, H. ; Poppe, U. ; Klein, N. ; Urban, K. ; Divin, Y.Y. ; Kotelyanskii, I.M.

Author_Institution

Forschungszentrum Julich GmbH, Germany

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

3009

Lastpage

3012

Abstract

To meet the requirements of high-frequency applications, we have fabricated YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary junctions on 2/spl times/12/spl deg/ [110] NdGaO/sub 3/ bicrystal substrates. Compared to reference junctions made on (100) SrTiO/sub 3/ bicrystals, the specific resistances R/sub n/A of the junctions on NdGaO/sub 3/ were usually several times higher. Furthermore, they showed RSJ-like behavior in a more limited temperature range, which might be due to weak links in the YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin film formed on twin boundaries of the NdGaO/sub 3/ bicrystal substrate. The electrical properties of these additional weak links have been studied by preparing YBa/sub 2/Cu/sub 3/O/sub 7-x/ thin-film bridges crossing a single twin boundary of a NdGaO/sub 3/ substrate. The critical current densities j/sub c/ were found to be on the order of 1/spl times/10/sup 6/ A/cm/sup 2/. Therefore, even for the smallest twin boundary junctions, a pronounced flux-flow-behavior is observed.

Keywords

Josephson effect; barium compounds; bicrystals; critical current density (superconductivity); flux flow; grain boundaries; high-temperature superconductors; neodymium compounds; superconducting thin films; twin boundaries; yttrium compounds; NdGaO/sub 3/; RSJ model; YBa/sub 2/Cu/sub 3/O/sub 7-x/ grain-boundary Josephson junction; YBa/sub 2/Cu/sub 3/O/sub 7/; critical current density; fabrication; flux flow; high-frequency application; specific resistance; thin film bridge; twin boundary; weak link; Bridge circuits; Etching; Fabrication; Grain boundaries; Ion beams; Josephson junctions; Plasma temperature; Sputtering; Substrates; Transistors;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.621957

Filename

621957