Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
TT: Fachverband Tiefe Temperaturen
TT 48: Superconductivity: Heterostructures, Andreev Scattering, Proximity Effect, Vortices
TT 48.8: Talk
Friday, March 30, 2012, 11:30–11:45, H 2053
Characterization and electronic transport properties of nanostructured Pb/Fe point contacts — •Jörg Gramich1, Gernot Goll1, Christoph Sürgers2, and Hilbert v. Löhneysen1,2 — 1DFG-Centrum für Funktionelle Nanostrukturen, KIT Karlsruhe — 2Physikalisches Institut, KIT Karlsruhe
We experimentally investigate the spin-polarized transport through nanostructured Pb/Fe point contacts at low temperatures. All samples are produced by in-situ evaporation of the metals on either side of a Si3N4 membrane with a nanostructured hole, resulting in clean metal interfaces. A direct measurement of the nanocontact size allows for the first time a comparison with theoretical models for contact-size estimates of heterocontacts. The ballistic transport regime for contacts with high Knudsen ratio is demonstrated by features in the spectra such as phonon peaks and the critical pair-breaking current of Pb. The spin polarization P of the current through the superconductor-ferromagnet contact is determined by means of Andreev reflection at the S/F interface. The observed systematic dependence on the contact radius a and superconducting transition temperature Tc is compared to previous measurements on Al/Fe nanocontacts.