Andreev conductance of a domain wall

TL;DR

This paper demonstrates that the Andreev conductance at a superconductor-ferromagnet interface is significantly enhanced by the presence of domain walls, being proportional to their total length, which impacts electron tunneling behavior.

Contribution

It reveals the direct proportionality between Andreev conductance and the total length of domain walls at the interface, providing new insights into spin-dependent tunneling phenomena.

Findings

Andreev conductance increases with domain wall length

Domain walls enhance subgap current in SF interfaces

Conductance is proportional to total domain wall length

Abstract

At low temperatures, the transport through a superconductor-ferromagnet tunnel interface is due to tunneling of electrons in pairs. Exchange field of a monodomain ferromagnet aligns electron spins and suppresses the two electron tunneling. The presence of the domain walls at the SF interface strongly enhances the subgap current. The Andreev conductance is proven to be proportional to the total length of domain walls at the SF interface.