Fig. 4. Decay length and damping parameter associated with the propagation of spin excitations.

a Amplitude spectra of self-inductance ∣ΔL₁₁∣ and mutual inductance ∣ΔL₂₁∣ measured in the SkX state at 25 K and +25 mT, whose ratio gives the decay rate of spin excitation amplitude during the propagation. b, c Magnetic field dependence of decay length l and damping parameter α measured at 25 K. d, e Temperature dependence of decay length and damping parameter for various spin excitation modes.