Josephson effect in Nb/Au/YBCO heterojunctions

Author

Ovsyannikov, Gennady A. ; Komissinski, Philippe V. ; Il´ichev, Evgeni ; Kislinski, Yuli V. ; Ivanov, Zdravko G.

Author_Institution

Inst. of Radio Eng. & Electron., Acad. of Sci., Moscow, Russia

Volume

13

Issue

2

fYear

2003

fDate

6/1/2003 12:00:00 AM

Firstpage

881

Lastpage

884

Abstract

c-axis oriented and 11° tilted YBa₂Cu₃O_x (YBCO) thin films were deposited on [110] NdGaO₃ and (7 10 2) NdGaO₃ substrates correspondingly. Nb/Au/YBCO heterojunctions were fabricated using photolithography and ion beam milling. I-V curves of the heterojunctions based on tilted YBCO films showed zero bias anomaly conductance peak and large excess current. We observed the second harmonic (∝ sin 2φ) of superconducting current in Nb/Au/YBCO heterojunctions in c-axis oriented YBCO films, although sinusoidal superconducting current-phase relation has been measured for heterojunctions in tilted ones. The obtained results are explained by d±s symmetry of YBCO superconducting order parameter.

Keywords

Josephson effect; barium compounds; critical current density (superconductivity); gold; high-temperature superconductors; ion beam mixing; niobium; photolithography; superconducting thin films; type II superconductors; yttrium compounds; I-V curves; Josephson effect; Nb-Au-YBa₂Cu₃O₇; Nb/Au/YBCO heterojunctions; NdGaO₃; high temperature superconductor; ion beam milling; large excess current; photolithography; sinusoidal superconducting current-phase relation; superconducting order parameter; zero bias anomaly conductance peak; Gold; Heterojunctions; Ion beams; Josephson effect; Lithography; Milling; Niobium; Sputtering; Superconducting films; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2003.814077

Filename

1211745