Vortex rectification effects in films with periodic asymmetric pinning

TL;DR

This study investigates vortex transport in an aluminum film with asymmetric antidots, revealing pronounced voltage rectification effects and behaviors akin to inertia ratchets, supported by experimental data and underdamped model calculations.

Contribution

It demonstrates that vortex rectification in asymmetric pinning landscapes exhibits underdamped dynamics, differing from standard models, and provides a theoretical fit to experimental results.

Findings

Pronounced voltage rectification effects observed.

Vortex behavior resembles inertia ratchets.

Underdamped model accurately fits experimental data.

Abstract

We study the transport of vortices excited by an ac current in an Al film with an array of nanoengineered asymmetric antidots. The vortex response to the ac current is investigated by detailed measurements of the voltage output as a function of ac current amplitude, magnetic field and temperature. The measurements revealed pronounced voltage rectification effects which are mainly characterized by the two critical depinning forces of the asymmetric potential. The shape of the net dc voltage as a function of the excitation amplitude indicates that our vortex ratchet behaves in a way very different from standard overdamped models. Rather, as demonstrated by the observed output signal, the repinning force, necessary to stop vortex motion, is considerably smaller than the depinning force, resembling the behavior of the so-called inertia ratchets. Calculations based on an underdamped ratchet model provide a very good fit to the experimental data.