Dipole-induced vortex ratchets in superconducting films with arrays of micromagnets

TL;DR

This paper explores how periodic arrays of micromagnets in superconducting films induce vortex ratchet effects and vortex-antivortex patterns, affecting transport properties through magnetic dipole interactions.

Contribution

It experimentally demonstrates the vortex ratchet effect induced by magnetic dipoles in superconducting films with engineered magnetic textures.

Findings

Ratchet effect observed with ac drive in superconducting films.

Magnetic textures produce vortex-antivortex patterns.

Transport properties are influenced by magnetic dipole interactions.

Abstract

We investigate the transport properties of superconducting films with periodic arrays of in-plane magnetized micromagnets. Two different magnetic textures are studied: a square array of magnetic bars and a close-packed array of triangular microrings. As confirmed by MFM imaging, the magnetic state of both systems can be adjusted to produce arrays of almost point-like magnetic dipoles. By carrying out transport measurements with ac drive, we observed experimentally a recently predicted ratchet effect induced by the interaction between superconducting vortices and the magnetic dipoles. Moreover, we find that these magnetic textures produce vortex-antivortex patterns, which have a crucial role on the transport properties of this hybrid system.