Guided vortex motion in superconductors with a square antidot lattice

TL;DR

This study investigates how a square antidot lattice in a superconducting film causes anisotropic vortex motion, revealing directional dependence and temperature effects on vortex mobility.

Contribution

It demonstrates the influence of a square antidot lattice on vortex motion, showing anisotropic mobility and directional vortex displacement in superconductors.

Findings

Vortex velocity modulus depends on angle with lower mobility along diagonals.

Vortex displacement aligns with principal axes, causing velocity-force misalignment.

Anisotropic vortex motion diminishes near the normal state.

Abstract

We have measured the in-plane anisotropy of the vortex mobility in a thin Pb film with a square array of antidots. The Lorentz force, acting on the vortices, was rotated by adding two perpendicular currents and keeping the amplitude of the net current constant. One set of voltage probes was used to detect the vortex motion. We show that the pinning landscape provided by the square antidot lattice influences the vortex motion in two different ways. First, the modulus of the vortex velocity becomes angular dependent with a lower mobility along the diagonals of the pinning array. Second, the vortex displacement is preferentially parallel to the principal axes of the underlying pinning lattice, giving rise to a misalignment between the vortex velocity and the applied Lorentz force. We show that this anisotropic vortex motion is temperature dependent and progressively fades out when approaching the normal state.