Tuning the dynamic behavior of a bicomponent artificial spin ice*

Artificial spin ices (ASI) are magnetic metamaterials initially designed to mimic the frustrated behavior of crystalline spin ice systems such as pyrochlore crystals. They show complex magnetic ordering and can exhibit exotic phase diagrams. Unlike their crystalline counterparts, the ASI geometry can be designed and the state of their constituent elements can be directly probed. Recent studies have focused on their dynamics at high frequencies (GHz to tens of GHz), as they can be used as magnonic metamaterials to modify the spin-wave properties by creating band gaps in the resonance spectra. Previous works have shown that different geometries produce unique dynamic spectra. Here, we performed angular-dependent broadband ferromagnetic resonance measurements on a square ASI composed of different materials for each sublattice (NiFe and FeCo). Our experiments show that the interaction between the sublattices results in unique spectra attributed to the sublattices. By performing micromagnetic simulations, we identify the modes observed in the experiment. Our results show that the interaction in the ASI can be tuned not only by the geometry of the lattice, but also by the proper choice of the materials.