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Non-locality and triplet superconductivity in S/F hybrid nanostructures

Objective

In Superconductor/Ferromagnet (S/F) bilayer and F/S/F/S/F multi-layer structures with ferromagnets with non- collinear magnetizations of the F layers, Fominov and Volkov [1, 2] have predicted that a triplet component (i.e. Cooper pairs with electron spins pointing in the same direction) generated artificially. This effect occurs at angles where the magnetization of the F layers is no parallel to each other. In addition to the realization of the triplet state in these types of S/F multi-layers, there is also the prediction of a transition from 0 to  phase shift between neighbouring S layers.

The possibility of switching between 0 and Â- junctions opens a whole new range of applications in super-conducting devices based on  triplet -junctions. The aim of the proposed research is to investigate these types of structures for different angles of magnetization of the F layers and verify the predicted induced triplet state superconductivity. Triplet  junction research is a very promising field with new applications in the field of super-conducting devices and quantum computing. The project here presented gives the possibility to realise these junctions with triplet pairing. A device which can switch from 0 to  junctions and from singlet to triplet state super-conductivity by applying external field would exhibit a functionality that is not possible using current S/F (singlet based)  -junctions. Finally we have designed an experiment to investigate non- locality of cooper pairs.

The main idea is to share the two electrons of a Cooper pair in two different magnetic domains and measure the Josephson current for the parallel and antiparallel configurations. We expect the Josephson critical current to be zero in the parallel configuration, and finite in the anti parallel one. [1] Ya. V. Fominov, A.A. Golubov, and M. Yu. Kupriyanov. JETP Lett. 77, No 9, 510, (2003) [2] A. F. Volkov, F.S. Bergeret, and K. B. Efetov, Phys. Rev. Lett. 90, 117006 (2003)

Call for proposal

FP6-2002-MOBILITY-5
See other projects for this call

Funding Scheme

EIF - Marie Curie actions-Intra-European Fellowships

Coordinator

LABORATOIRE DE PHYSIQUE DES SOLIDES D'ORSAY