YIG/CoFeB Bilayer Magnonic Isolator

We demonstrate a magnonic isolator based on a bilayer structure of yttrium iron garnet (YIG) and cobalt iron boron (CoFeB). The bilayer exhibits pronounced nonreciprocal spin-wave propagation, enabled by dipolar coupling and the magnetic properties of the two layers. The YIG layer provides low damping and efficient spin-wave propagation, whereas the CoFeB layer introduces strong magnetic anisotropy, critical for achieving the isolator functionality. Experimental results, supported by numerical simulations, show unidirectional propagation of magneto-static surface spin waves, significantly suppressing backscattered waves. This behavior was confirmed through wavevector-resolved and microfocused Brillouin light scattering measurements and is supported by numerical simulations. The developed YIG/SiO$_{2}$/CoFeB bilayer magnonic isolator demonstrates the feasibility of leveraging nonreciprocal spin-wave dynamics for functional magnonic devices, paving the way for energy-efficient, wave-based signal processing technologies.