Temperature dependences of spin-diffusion lengths of Cu and Ru layers

Ferromagnetic resonance (FMR) was measured in Cu/Ni80Fe20/normal-metal: NM (d)/Pt, Cu/Ni80Fe20/NM (d) films with various d values to clarify the temperature dependence of spin-diffusion length induced by the precession of magnetization on Gilbert damping. The films were fabricated by rf magnetron sputtering. The out-of-plane angular dependences of FMR resonance field and linewidth were analyzed using a Landau-Lifshitz-Gilbert equation, and the Gilbert damping parameter G of NiFe was obtained. The obtained spin-diffusion lengths lambda(SD) were 350 and 950 nm at 300 and 4.5 K, respectively. The spin-flip probability of the Cu layer was obtained using the temperature dependence of FMR linewidth. These results were then compared with the calculated data of the temperature dependence of spin-diffusion length.