Transverse ratchet effect and superconducting vortices: Simulation and experiment

TL;DR

This paper investigates a transverse ratchet effect in superconducting vortices within Nb/Ni hybrid films, combining experimental measurements and numerical simulations to understand vortex motion under ac currents.

Contribution

It demonstrates the first combined experimental and simulation study of the transverse ratchet effect in superconductor/ferromagnet hybrids, highlighting the role of intrinsic pinning.

Findings

Measured a transverse ratchet voltage in Nb/Ni hybrid films.

Simulations replicate the experimental effect using Langevin dynamics.

Intrinsic pinning is fundamental to the ratchet mechanism.

Abstract

A transverse ratchet effect has been measured in magnetic/superconducting hybrid films fabricated by electron beam lithography and magnetron sputtering techniques. The samples are Nb films grown on top of an array of Ni nanotriangles. Injecting an ac current parallel to the triangle reflection symmetry axis yields an output dc voltage perpendicular to the current, due to a net motion of flux vortices in the superconductor. The effect is reproduced by numerical simulations of vortices as Langevin particles with realistic parameters. Simulations provide an intuitive picture of the ratchet mechanism, revealing the fundamental role played by the random intrinsic pinning of the superconductor.