Guided vortex motion in a ferromagnet-superconductor bilayer

TL;DR

This study investigates how vortex motion in a ferromagnet-superconductor bilayer is guided by anisotropic pinning landscapes, revealing angle-dependent critical currents and signs of coherent vortex flow near magnetic domain walls.

Contribution

It demonstrates the influence of anisotropic pinning on vortex dynamics in ferromagnet-superconductor bilayers, highlighting angle-dependent effects and coherence signatures.

Findings

Critical current and flux flow resistance depend elliptically on the strip angle.

Guided vortex motion occurs at different angles relative to twin lines.

Coherent vortex motion signatures are observed near magnetic domain walls.

Abstract

Vortex motion in ferromagnetic-superconducting bilayers constituted by thin YBa$_2$Cu$_3$O$_{7-\delta}$ film deposited on the top of thin manganite La$_{0.67}$Sr$_{0.33}$MnO$_3$ film has been investigated. Both films were deposited on uniformly twinned single-crystalline substrates and patterned into strips directed at different angles to the twin lines pattern. These conditions lead to the guided vortex motion at different angles to the periodic pinning potential. It has been established that critical current and flux flow resistance in such an anisotropic pinning landscape-scale follow the elliptic dependence on the angle of the direction of the strip. For vortex flow at the directions close to the perpendicular to magnetic domain walls, signatures of the coherence in the vortex motion have been observed.