Frequency comb in a macroscopic mechano-magnetic artificial spin ice

Artificial spin ices are metamaterials composed of interacting nanomagnets exhibiting frustration. Their resonant magnetization dynamics have been broadly investigated from fundamental and applied points of view. In this work, we realize a dynamically driven macroscopic mechano-magnetic artificial spin ice, or macro-ASI, where permanent magnets are allowed to rotate on specially designed hinges and exhibit natural resonance frequencies on the order of several Hertz. A nonlinear dynamical regime is achieved experimentally and well reproduced by numerical modelling. The modulation of the magnetic coupling leads to a frequency comb that manifests itself as an amplitude-phase modulation of the magnets' motion due to a metastable condition, i.e., a Hopf bifurcation. Our results not only demonstrate a striking similarity across different physical systems, but also suggest that the mechanism to enable nonlinear phenomena could be realized in nanoscale systems using microresonators decorated with magnetic materials to dynamically modulate their coupling.