Spin valve Josephson junctions

Author

Bell, Christopher ; Burnell, Gavin ; Leung, Chi-Wah ; Tarte, Edward J. ; Blamire, Mark G.

Author_Institution

Mater. Sci. Dept., IRC in Supercond. & IRC Nanotechnol., Cambridge, UK

Volume

15

Issue

2

fYear

2005

fDate

6/1/2005 12:00:00 AM

Firstpage

908

Lastpage

911

Abstract

We are currently researching Nb-based Josephson junctions with magnetic barriers in which the magnetic character can be actively changed, with the final aim of producing a magnetically controllable π-junction. Pseudo-spin-valve Nb/Fe₂₀Ni₈₀/Cu/Co/Nb Josephson junctions have been grown by d.c. magnetron sputtering. As we have previously reported, the spin-valve magnetoresistance could be measured at high bias at 4.2 K. The zero field critical current of the junction could also be varied by preparing the spin valve in different remanent states. Jumps and smooth changes in the critical current were observed, in line with the changes in magnetoresistance. In this work we discuss the effect of varying the total barrier thicknesses on the change in the critical current, as well as varying the Co:Fe₂₀Ni₈₀ ratio.

Keywords

Permalloy; cobalt; copper; magnetoresistance; niobium; spin valves; sputter deposition; superconducting junction devices; 4.2 K; Josephson junctions; Nb-Fe₂₀Ni₈₀-Cu-Co-Nb; dc magnetron sputtering; magnetic barriers; magnetoresistive devices; pseudo-spin valve; remanent states; spin valve magnetoresistance; Critical current; Current measurement; Josephson junctions; Magnetic field measurement; Magnetoresistance; Spin valves; Superconducting epitaxial layers; Superconducting films; Superconducting magnets; Temperature; Josephson junctions; magnetoresistive devices;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2005.850112

Filename

1439786