Reconfigurable Dipolar Spin-Wave Coupling in a Bilateral Yttrium Iron Garnet Structure

We report on the coupling of spin waves propagating as guided modes of yttrium iron garnet stripes. Three stripes are placed parallel to each other and separated by gaps that are small enough to pro-vide nearest-neighbor coupling. We term this geometry "bilateral stripes." The origin of the coupling is the long-ranging dynamic, stray (dipole) field of the precessing magnetization vector. We propose con-trolling characteristics of this coupling through variation of the static magnetization angle with respect to the main axes of the geometry. We verified the functionality of the proposed magnonic coupler with a micromagnetic simulation of spin-wave propagation along the bilateral stripes. The micromag-netic numerical simulation yielded spectra of transmission of spin waves through the device prototype. Analysis of those spectra revealed that the bilateral stripes can be used as a functional unit in planar magnonic networks-they can be employed as a directional coupler, spin-wave multiplexer, or microwave power divider. Using Brillouin light scattering spectroscopy, we experimentally demonstrated spin-wave transport along the bilateral stripes. We were able to control the spin-wave routing between the stripes ("magnetic channels") by varying the angle of the bias magnetic field.