Spin waves with large decay length and few 100 nm wavelengths in thin yttrium iron garnet grown at the wafer scale

Using conventional coplanar waveguides (CPWs), we excited spin waves with a wavelength λ down to 310 nm in a 200 nm thin yttrium iron garnet film grown by liquid phase epitaxy. Spin-wave transmission was detected between CPWs that we separated by up to 2 mm. For magnetostatic surface spin waves, we found a large nonreciprocity of 0.9 and a high group velocity vg of up to 5.4 km/s. The extracted decay length ld amounted to 0.86 mm. Small λ, high vg, and large ld are key figures of merit when aiming at non-charged based signal transmission and logic devices with spin waves.