Observation of Andreev-Saint-James reflections in nano-scale planar superconductor to ferromagnet contacts

We fabricated nanoscale ferromagnetic (F) Nickel/superconducting (S) indium junctions which show that spin polarization effects on the contact conductance can be observed in a planar geometry. The data demonstrate that the Andreev-Saint-James [Sov. Phys. JETP 19, 1228 (1964) and J. Phys. (Paris) 25, 899 (1964)] electron-hole reflections at the F/S interface, which are sensitive to the polarization of the F side, dominate the conductance of the contact at low bias. The simplicity of fabrication makes these junctions appealing for use in multiterminal SF structures. (c) 2008 American Institute of Physics.