Abrikosov vortices in SF bilayers

TL;DR

This paper analyzes the behavior of supercurrents around Abrikosov vortices in superconductor-ferromagnet bilayers, revealing controllable current reversal effects due to interface transparency and exchange fields.

Contribution

It provides analytical solutions for supercurrent distributions in SF bilayers and uncovers the controllable reversal of supercurrent direction around vortices.

Findings

Supercurrent reversal can occur in F layers compared to S layers.

Reversal is controllable via interface transparency and exchange field.

Phase shift between singlet and triplet components causes the effect.

Abstract

We study the spatial distribution of supercurrent circulated around an Abrikosov vortex in an SF bilayer in perpendicular magnetic field. Within the dirty limit regime and circular cell approximation for the vortex lattice, we derive the conditions when the Usadel equations the F layer can be solved analytically. Using the obtained solutions, we demonstrate the possibility of reversal of direction of proximity induced supercurrents around the vortex in the F layer compared to that in the S-layer. The direction of currents can be controlled either by varying transparency of the SF interface or by changing an exchange field in a ferromagnet. We argue that the origin of this effect is due the phase shift between singlet and triplet order parameter components induced in the F-layer. Possible ways of experimental detection of the predicted effect are discussed.