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SFINX Sintesi della relazione

Project ID: 505587
Finanziato nell'ambito di: FP6-NMP
Paese: United Kingdom

Final Report Summary - SFINX (Superconductivity - ferromagnetism interplay in nanostructured hybrid systems)

The aim of the SFINX project was to pursue a research into hybrid nanostructures which incorporate superconducting (S) and ferromagnetic (F) metal components. It performed a research into the fundamental electronic and magnetic phenomena occurring in superconductor and ferromagnetic-based hybrids as well as into dynamic and kinetic transport effects and into spin filtering.

The project achieved the following objectives:
- deployment of methods in order to grow and control aluminates (AlOx) as well as magnesium oxide (MgO) barriers between ferromagnetic and normal metal (N) or ferromagnetic superconductor structures. Theory which relates to magnetisation texture and magnetisation dynamics near the interface of ferromagnetic and normal metal or near the interface of two ferromagnetic metals was developed;
- creation of superconducting films of niobium (Nb) with embedded magnetic nanoclusters and study of the co-existence of superconductivity and ferromagnetism in S films. The project also managed to assess the influence of ferromagnetic cluster arrays on the critical current and temperature of the S film. Considering the depolarisation effect due to the non-colinearity of cluster polarisation, a theory was developed concerning the magnetic field dependence of resistivity of F materials on the polarisation state of clusters;
- development of a theoretical framework for the spin-dependent transport in superconducting spin valves, formulation of the theory of tunnelling of spin-polarised quasi-particles through a thin superconducting layer in F-S-F structures. It also achieved in manufacturing hybrid micro-circuits, including ring-shaped structures in order to study interference effects such as the Aharonov-Bohm effect and fork-shaped structures in order to study cross-correlation in current noise caused by Andreev reflection. A new type of a micro-cooler was created which is based on a series of S-N tunnel junctions and can be used to provide cooling from 4 Kelvin (K) to 100 microkelvin;
- considering the strong spin dependence of electron scattering on compositional disorder in a diluted ferromagnetic alloy the project developed a theory concerning the critical current in superconductor-ferromagnetic alloy-superconductor trilayers. It also developed a model and an efficient calculation method in order to describe the proximity effect in S-F heterostructures as well as it evaluated the Green functions, the density of states and the Josephson current which depend on the magnetic configuration of an S-F-S structure and, mainly, on its ferromagnetic texture. Finally, a superconducting spin-valve effect in niobate / copper nickel (Nb/CuNi) although it is rather weak.

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United Kingdom