Europhys. Lett.
Volume 68, Number 3, November 2004
Page(s) 447 - 452
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 09 October 2004
Europhys. Lett., 68 (3), pp. 447-452 (2004)
DOI: 10.1209/epl/i2004-10210-x

Magnetic-field-induced supercurrent enhancement in hybrid superconductor/magnet metal structures

V. N. Krivoruchko

Donetsk Physics & Technology Institute NASU R. Luxemburg Str., 72, Donetsk-114, 83114 Ukraine

received 27 April 2004; accepted in final form 3 September 2004
published online 9 October 2004

The dc transport properties of the (S/M)I(M/S) tunnel structure -proximity coupled superconductor (S) and magnetic (M) layers separated by an insulator (I)- in a parallel magnetic field have been investigated. We choose for the M metal the one in which the effective magnetic interaction, whether it arises from direct exchange interaction or due to configuration mixing, aligns spins of the conducting electrons antiparallel to the localized spins of magnetic ions. For tunnel structures under consideration, we predict that there are the conditions when the destructive action of the internal and applied magnetic fields on Cooper pairs is weakened and the increase of the applied magnetic field causes the field-induced enhancement of the tunnel critical current. The experimental realization of the novel interesting effect of the interplay between superconducting and magnetic orders is also discussed.

74.78.Fk - Multilayers, superlattices, heterostructures.
74.50.+r - Tunneling phenomena; point contacts, weak links, Josephson effects.
75.70.Cn - Magnetic properties of interfaces (multilayers, superlattices, heterostructures).

© EDP Sciences 2004