Asymmetric weak-pinning superconducting channels: vortex ratchets

TL;DR

This paper demonstrates how asymmetric weak-pinning superconducting channels can control vortex motion, showing a vortex ratchet effect with asymmetric responses influenced by magnetic field and driving force.

Contribution

The study introduces asymmetric weak-pinning channels in superconductors to induce and analyze vortex ratchet effects, highlighting the role of channel shape in vortex dynamics.

Findings

Asymmetric channels produce a significant vortex ratchet effect.

Vortex motion shows asymmetry in depinning and flux flow.

The effect depends on magnetic field and driving force amplitude.

Abstract

The controlled motion of objects through narrow channels is important in many fields. We have fabricated asymmetric weak-pinning channels in a superconducting thin-film strip for controlling the dynamics of vortices. The lack of pinning allows the vortices to move through the channels with the dominant interaction determined by the shape of the channel walls. We present measurements of vortex dynamics in the channels and compare these with similar measurements on a set of uniform-width channels. While the uniform-width channels exhibit a symmetric response for both directions through the channel, the vortex motion through the asymmetric channels is quite different, with substantial asymmetries in both the static depinning and dynamic flux flow. This vortex ratchet effect has a rich dependence on magnetic field and driving force amplitude.