Multiple peaks in the angular and field dependence of the critical currents in Nb-47wt%Ti/Cu multilayers

Author

Kadyrov, E. ; Cooley, L.D. ; Gurevich, A. ; Lee, P.J. ; Larbalestier, D.C.

Author_Institution

Appl. Supercond. Center, Wisconsin Univ., Madison, WI, USA

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

1205

Lastpage

1208

Abstract

The effect of Nb-Ti layer thickness d/sub s/ on the angular and field dependencies of J/sub c/ in Nb-47wt.% Ti/Cu multilayers was investigated. J/sub c/ exhibits several peaks in the field and angular dependencies for superconductor and pin layer thickness comparable to the coherence and proximity lengths. The shape of the J/sub c/(B) curve strongly depends on the thickness of Nb-Ti layer. A single peak is present for d/sub s/>10 nm and multiple peaks (two and three) are observed in a sample with d/sub s/=10 nm. The low field peak is temperature independent, while the high-field peaks have a pronounced temperature dependence. We suggest that a crossover between dominant pinning mechanisms and orientational transitions in the vortex lattice is responsible for the observed behavior of J/sub c/(B).

Keywords

copper; critical current density (superconductivity); flux pinning; flux-line lattice; niobium alloys; proximity effect (superconductivity); superconducting superlattices; titanium alloys; type II superconductors; 10 nm; Nb-Ti/Cu multilayers; NbTi-Cu; angular dependence; critical currents; dominant pinning mechanisms; field dependence; multiple peaks; orientational transitions; pin layer thickness; vortex lattice; Copper; Critical current; Flux pinning; Lattices; Nonhomogeneous media; Shape; Superconducting devices; Superconducting epitaxial layers; Superconducting filaments and wires; Temperature dependence;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.620725

Filename

620725