High spin-wave propagation length consistent with low damping in a metallic ferromagnet

We report ultra-low intrinsic magnetic damping in Co25Fe75 heterostructures, reaching the low 10E−4 regime at room temperature. By using a broadband ferromagnetic resonance technique, we extracted the dynamic magnetic properties of several Co25Fe75-based heterostructures with varying ferromagnetic layer thickness. By estimating the eddy current contribution to damping, measuring radiative damping and spin pumping effects, we extrapolated an intrinsic damping of α0 ≤ 3.05 × 10E−4. Furthermore, using Brillouin light scattering microscopy we measured spin-wave propagation lengths of up to (21 ± 1) μm in a 26 nm thick Co25 Fe75 heterostructure at room temperature, which is in excellent agreement with the measured damping.