# Imaging anisotropic vortex dynamics in FeSe

## TL;DR

This paper investigates the anisotropic behavior of vortex pinning in FeSe using scanning SQUID susceptibility, revealing that vortices move easily along domain walls but are strongly pinned perpendicular to them, shedding light on vortex dynamics and nematicity.

## Contribution

It introduces a novel experimental approach combining local magnetic field application with vortex imaging to characterize anisotropic vortex pinning in FeSe.

## Key findings

- Vortices move easily along twin domain walls.
- Vortices are strongly pinned perpendicular to domain walls.
- Pinning anisotropy is linked to domain wall structures.

## Abstract

Strong vortex pinning in FeSe could be useful for technological applications and could provide clues about the coexistence of superconductivity and nematicity. To characterize the pinning of individual, isolated vortices, we simultaneously apply a local magnetic field and image the vortex motion with scanning SQUID susceptibility. We find that the pinning is highly anisotropic: the vortices move easily along directions that are parallel to the orientations of twin domain walls and pin strongly in a perpendicular direction. These results are consistent with a scenario in which the anisotropy arises from vortex pinning on domain walls and quantify the dynamics of individual vortex pinning in FeSe.