Analysis of the barrier in vertically-stacked interface-treated Josephson junctions

Author

Inoue, Masumi ; Yoshinaga, Yasuyuki ; Wakita, Kazuya ; Taniike, Koichiro ; Kimura, Taishi ; Fujimaki, Akira ; Hayakawa, Hisao

Author_Institution

Dept. of Quantum Eng., Nagoya Univ., Japan

Volume

15

Issue

2

fYear

2005

fDate

6/1/2005 12:00:00 AM

Firstpage

141

Lastpage

144

Abstract

The authors have investigated the structure and the composition of the barrier in YBCO vertically-stacked-type interface-treated Josephson junctions by TEM and TEM-EDS. The barrier was formed by the Ar ion milling of the base YBCO electrode surface and the subsequent annealing. For a sample treated with accelerating voltage (V_acc) of 1300 V, we observed Y₂O₃ phases in the barrier. In contrast, for a sample with V_acc=700 V, we could observe few Y₂O₃ phases. Our TEM observation suggested that junctions with higher J_c fabricated with lower V_acc would have thinner and more uniform barriers. In addition, the composition of the barrier was Y-rich and Cu-poor, and such deviation decreased with decreasing V_acc. These tendencies well correspond to the results for ramp-edge-type junctions reported so far.

Keywords

X-ray spectra; annealing; barium compounds; high-temperature superconductors; superconducting junction devices; transmission electron microscopy; yttrium compounds; 1300 V; 700 V; Ar ion milling; TEM observation; Y₂O₃; YBCO; YBa₂Cu₃O_7-x; accelerating voltage; annealing; barrier analysis; energy dispersive X-ray spectroscopy analysis; vertically-stacked interface-treated Josephson junctions; Argon; Circuits; Fabrication; High temperature superconductors; Josephson junctions; Niobium; Reproducibility of results; Spectroscopy; Superconducting films; Yttrium barium copper oxide; Barrier; Josephson junction; YBCO; vertically-stacked interface-treated junction;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2005.849718

Filename

1439596