Evaluation of Spin Hall Angle and Spin Diffusion Length by Using Spin Current-Induced Ferromagnetic Resonance

We experimentally demonstrate the thickness dependence of the spin current-induced ferromagnetic resonance in Ni80Fe20/nonmagnetic (Pt,Pd) bilayer thin films. The spectrum shape depends on the Ni80Fe20 layer thickness, due to extrinsic excitation in addition to the spin Hall effect. Detailed analysis of the thickness dependence of the spectrum, both for Ni80Fe20 and nonmagnetic layers, provides the spin Hall angle (Pt: 0.022±0.004, Pd: 0.008±0.002) and spin diffusion length (Pt: 1.2±0.06 nm, Pd: 2.0±0.09 nm).