  Ratchet devices allow turning an ac input signal into a dc output signal. A
ratchet device is set by moving particles driven by zero averages forces on
asymmetric potentials. Hybrid nanostructures combining artificially fabricated
spin-ice nanomagnet arrays with superconducting films have been identified as a
good choice to develop ratchet nanodevices. In our case, the asymmetric
potentials are provided by charged N\'eel walls located in the vertices of the
magnetic honeycomb array, whereas the role of moving particles is played by
superconducting vortices. We have experimentally obtained ratchet effect for
different spin ice I configurations and for vortex lattice moving parallel or
perpendicular to the magnetic easy axes. Remarkably, the ratchet magnitudes are
similar in all the experimental runs; i. e. different spin ice I configurations
and in both relevant directions of the vortex lattice motion. We have simulated
the interplay between vortex motion directions and a single asymmetric
potential. It turns out vortices interact with uneven asymmetric potentials,
when they move with trajectories crossing charged N\'eel walls with different
orientations. Moreover, the appropriate asymmetric pair potentials which
generate the local ratchet effect have been identified. In this rocking ratchet
the particles (vortices) on the move are interacting each other (vortex
lattice); therefore, the ratchet local effect turns into a global macroscopic
effect. In summary, this ratchet device benefits from interacting particles
moving in robust and topological protected type I spin ice landscapes.

Superconductivity