Experimental ratchet effect in superconducting films with periodic arrays of asymmetric potentials

TL;DR

This study demonstrates a vortex lattice ratchet effect in superconducting Nb films with nanometric Ni triangle arrays, showing how asymmetric pinning potentials induce a net dc-voltage under ac current, influenced by geometry, temperature, and vortex density.

Contribution

First experimental observation of vortex ratchet effect in superconducting films with engineered asymmetric pinning arrays, analyzing various influencing factors.

Findings

Ratchet effect produces measurable dc-voltage under ac current.

Array geometry and temperature significantly affect the ratchet efficiency.

Vortex density modulates the magnitude of the ratchet response.

Abstract

A vortex lattice ratchet effect has been investigated in Nb films grown on arrays of nanometric Ni triangles, which induce periodic asymmetric pinning potentials. The vortex lattice motion yields a net dc-voltage when an ac driving current is applied to the sample and the vortex lattice moves through the field of asymmetric potentials. This ratchet effect is studied taking into account the array geometry, the temperature, the number of vortices per unit cell of the array and the applied ac currents.