Electrical properties of YBCO/Ca-YBCO/YBCO trilayer Josephson junctions using c-axis oriented films

Author

Wang, J.Q. ; Muruyama, M. ; Ota, T. ; Terai, H. ; Inoue, M. ; Fujimaki, Akira ; Hayakawa, H.

Author_Institution

Dept. of Electron., Nagoya Univ., Japan

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

2948

Lastpage

2951

Abstract

We have studied electrical properties of YBCO/Y/sub 0.7/Ca/sub 0.3/Ba/sub 2/Cu/sub 3/O/sub 7-x/ (Ca-YBCO)/YBCO trilayer junctions using c-axis oriented films. The Ca-YBCO films used here are the overdoped version of YBCO and show transition temperatures around 55 K. All of the junctions show RSJ-like current-voltage characteristics in a certain temperature range, though the range decreases with the Ca-YBCO interlayer thickness. For an applied magnetic field, the junctions show Fraunhofer pattern, indicating a Josephson coupling through the interlayers. The normal resistance of the junctions is proportional to the thickness of the interlayer, suggesting little interface resistance. The exponential dependence of the critical current on temperature and that on the interlayer thickness mean that the junctions behave as SNS junctions. These experimental results imply the proximity effect along c-axis in high temperature superconductors.

Keywords

Josephson effect; barium compounds; calcium compounds; high-temperature superconductors; superconducting thin films; yttrium compounds; Fraunhofer pattern; RSJ model; SNS junction; YBCO/Ca-YBCO/YBCO trilayer Josephson junction; YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 0.7/Ca/sub 0.3/Ba/sub 2/Cu/sub 3/O/sub 7/-YBa/sub 2/Cu/sub 3/O/sub 7/; c-axis oriented film; critical current; current-voltage characteristics; electrical properties; high temperature superconductor; magnetic field; normal resistance; overdoped YBCO interlayer; transition temperature; Couplings; Critical current; Current-voltage characteristics; Magnetic fields; Magnetic films; Proximity effect; Superconducting transition temperature; Temperature dependence; Temperature distribution; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.621928

Filename

621928