Spin transport parameters in Ni 80 Fe 20 / Ru and Ni 80 Fe 20 / Ta bilayers

We present a systematic study of the spin transport properties in two different bilayer systems, Ni80Fe20/Ru and Ni80Fe20/Ta, combining ferromagnetic resonance (FMR) and inverse spin Hall effect (ISHE) voltage measurements. We have estimated the effective spin mixing conductance gl by analyzing the permalloy (Py) thickness dependence of the FMR linewidth obtaining gl = (3.8 0.7) x 10(15) cm(-2) and gl = (1.3 0.4) x 10(15) cm(-2) for Py/Ru and Py/Ta, respectively. Analyzing the Ta thickness dependence of the ISHE voltage, we have been able to extract the spin diffusion length, Asp = 1.5 0.5 nm, and spin Hall angle, OsH = -0.03 0.01, of Ta. From the two series of Py/Ta bilayers with thickness variation of ferromagnetic and nonmagnetic layers, respectively we demonstrate a path to estimate the spin diffusion length from the experimental data, independent of the spin Hall angle and the microwave field amplitude.