Electron transport in a mesoscopic superconducting / ferromagnetic hybrid conductor

TL;DR

This study investigates how superconductivity in aluminum influences electron transport in a ferromagnetic cobalt conductor within a hybrid device, highlighting the role of interface transparency and magnetic domain structure.

Contribution

It provides experimental insights into the impact of superconducting aluminum on ferromagnetic cobalt conductors, emphasizing the importance of interface transparency and magnetic domains.

Findings

Superconductivity significantly reduces resistance in the ferromagnet when interface is transparent.

Resistance decrease depends on temperature, bias current, and magnetic field.

Magnetic domain structure affects electron transport asymmetry.

Abstract

We present electrical transport experiments performed on submicron hybrid devices made of a ferromagnetic conductor (Co) and a superconducting (Al) electrode. The sample was patterned in order to separate the contributions of the Co conductor and of the Co-Al interface. We observed a strong influence of the Al electrode superconductivity on the resistance of the Co conductor. This effect is large only when the interface is highly transparent. We characterized the dependence of the observed resistance decrease on temperature, bias current and magnetic field. As the differential resistance of the ferromagnet exhibits a non-trivial asymmetry, we claim that the magnetic domain structure plays an important role in the electron transport properties of superconducting / ferromagnetic conductors.