Fabrication of Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ thin film grain boundary junctions

Author

Ohbayashi, K. ; Fujii, H. ; Kuzuhara, A. ; Ohtsuki, T. ; Inoue, M. ; Fujimaki, A. ; Hayakawa, H.

Author_Institution

Res. & Dev. Center, NGK Spark Plug Co. Ltd., Nagoya, Japan

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

2816

Lastpage

2819

Abstract

As-grown high-quality superconducting thin films of the Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ were prepared by RF magnetron sputtering with a regulated shuttering technique. 2223 phase films with a 2201 phase buffer layer were deposited on MgO (100) substrates under rigorous control of the bismuth content and valence. As a source of bismuth, Bi(metal) and Bi/sub 2/Sr/sub 2/CuO/sub x/ targets were used. At the preparation no post-treatment steps were performed. The zero resistivity critical temperature of the as-grown film was 107.3 K. Using these films, Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ step-edge and bicrystal Josephson junctions were prepared. At step-edge junctions, Josephson current was observed up to 41 K, below this temperature I-V curves were RSJ-like. On the other hand, bicrystal junctions were fabricated,on the bicrystal MgO (100) substrate with a misorientation angle of 24/spl deg/. Typical RSJ model I-V curves were observed up to 60 K. The modulation depth goes up to 90%. I/sub c/R/sub n/ values were about 1.0 mV at 4.2 K.<>

Keywords

Josephson effect; bicrystals; bismuth compounds; calcium compounds; critical currents; grain boundaries; high-temperature superconductors; sputter deposition; strontium compounds; superconducting device testing; superconducting junction devices; superconducting thin films; superconducting transition temperature; 107.3 K; 2201 phase buffer layer; 2223 phase films; 4.2 to 60 K; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ thin film grain boundary junctions; I-V curves; I/sub c/R/sub n/ values; Josephson current; MgO; MgO (100) substrates; RF magnetron sputtering; RSJ-like characteristics; bicrystal Josephson junctions; critical currents; high-quality superconducting thin films; misorientation angle; modulation depth; regulated shuttering technique; step-edge junctions; zero resistivity critical temperature; Bismuth; Fabrication; Radio frequency; Sputtering; Strontium; Substrates; Superconducting films; Superconducting magnets; Superconducting thin films; Temperature;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.403177

Filename

403177