Spin polarized current and Andreev transmission in planar superconducting-ferromagnetic Nb-Ni junctions

TL;DR

This paper investigates spin-polarized tunneling and Andreev reflection in Nb/Ni superconducting-ferromagnetic junctions, using experimental measurements and three modeling approaches to understand current polarization and barrier structure.

Contribution

It introduces a simple quasiclassical model to accurately extract current polarization without an external magnetic field in Nb/Ni junctions.

Findings

Successful fitting of experimental data with the quasiclassical model

Extraction of current polarization without magnetic field

Insights into the microscopic barrier structure

Abstract

We have measured and modeled, using three different approaches, the tunneling current in a Nb/NbxOy/Ni planar tunnel junction. The experimental data could be fitted and the correct current polarization could be extracted using a simple quasiclassical model, even in the absence of an applied magnetic field. We also discuss the microscopic structure of the barrier.