Grain boundary Josephson devices by YBaCuO films and 77 K operations

Author

Yamashita, T. ; Kawakami, A. ; Noge, S. ; Xu, W. ; Takata, M. ; Komatsu, T. ; Matusita, K.

Author_Institution

Nagaoka Univ. of Technol., Japan

Volume

25

Issue

2

fYear

1989

fDate

3/1/1989 12:00:00 AM

Firstpage

923

Lastpage

926

Abstract

Magnetron sputtering and screen printing methods were used to fabricate YBaCuO films with thicknesses of 5 to 30 μm. The annealing of the films at 1000°C gave abnormal grain growth. The grain size of the films was about 2 to 70 μm. With photolithography and razor cutting techniques, the films were formed into bridge-type Josephson junctions having a few grain boundaries in the bridge regions. In the devices, clear Shapiro steps and SQUID (superconducting quantum interference devices) patterns were observed at 77 K. The experiments showed that all currents flowing through grain boundaries are Josephson currents in YBaCuO polycrystalline films. Clear Josephson effects were observed in about 30% of the fabricated devices. Such devices may have high potential for high-frequency detectors and SQUID flux sensors operative at 77 K

Keywords

Josephson effect; barium compounds; grain boundaries; high-temperature superconductors; superconducting junction devices; superconducting thin films; yttrium compounds; 5 to 30 micron; 77 K; SQUID flux sensors; SQUID patterns; Shapiro steps; YBaCuO films; annealing; bridge-type Josephson junctions; grain boundary Josephson devices; grain growth; grain size; high temperature superconductor; high-frequency detectors; magnetron sputtering; photolithography; razor cutting; screen printing; thicknesses; Grain boundaries; Josephson effect; Josephson junctions; Magnetic devices; Magnetic flux; SQUIDs; Superconducting devices; Superconducting films; Superconducting magnets; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.92438

Filename

92438