Size Dependence of Current Spin Polarization Through Superconductor/Ferromagnet Nanocontacts

TL;DR

This study investigates how the spin polarization of current through superconductor/ferromagnet nanocontacts varies with contact size, revealing a decrease in polarization linked to spin-orbit scattering effects.

Contribution

It provides experimental evidence of size-dependent spin polarization reduction and connects density-of-states with transport polarization in nanostructured contacts.

Findings

Spin polarization decreases as contact resistance decreases.

Spin-orbit scattering reduces spin polarization.

Transport polarization correlates with density-of-states.

Abstract

The spin polarization P of the transport current through the interface between superconducting Al and ferromagnetic Fe is determined by means of Andreev reflection at nanostructured point contacts. We observe a systematic decrease of P with decreasing contact resistance. Our data provide evidence for the reduction of P by spin-orbit scattering and thus establish a link between density-of-states and transport spin polarizations.