Active Control of Dipole-Exchange Coupled Magnon Modes in Nanoscale Bicomponent Magnonic Crystals

Bicomponent magnonic crystals (BMCs) are metasurfaces formed using two dissimilar materials, which offer a richer manipulation of spin waves and promising spin-wave based computation, communication, and signal processing. Here, the intricate interplay of spin dynamics between two different materials Co50Fe50 and Ni80Fe20 forming a BMC is exploited experimentally. Optimally engineered interface leads to interelement exchange coupling combined with the long-range dipolar coupling as confirmed by micromagnetic simulations. These couplings have been further tuned by systematic variation of the filling fraction of Co50Fe50 and Ni80Fe20 in the BMC. Moreover, the characteristic properties of spin wave spectra are found to be highly sensitive to the bias-field strength. Further numerical simulations based on experimentally determined parameters demonstrate long-distance and high-speed spin-wave propagation in such BMCs controlled by the filling fraction and offer a diode-like on/off mechanism determined by the applied magnetic field strength. These observations will lead to the development of high-speed reconfigurable magnonic devices controlled by external parameters.