Determining Key Spin-Orbitronic Parameters via Propagating Spin Waves

International audienceWe characterize spin-wave propagation and its modification by an electrical current in permalloy(Py)/Pt bilayers with Py thickness between 4 and 20 nm. First, we analyze the frequency nonreciprocity of surface spin waves and extract from it the interfacial Dzyaloshinskii-Moriya interaction constant D s accounting for an additional contribution due to asymmetric surface anisotropies. Second, we measure the spin-wave relaxation rate and deduce from it the Py/Pt spin-mixing conductance g ↑↓ eff. Last, applying a dc electrical current, we extract the spin Hall conductivity σ SH from the change of spin-wave relaxation rate due to the spin Hall spin-transfer torque. We obtain a consistent picture of the spin-wave propagation data for different film thicknesses using a single set of parameters D s = 0.25 pJ/m, g ↑↓ eff = 3.2 × 10 19 m −2 and σ SH = 4 × 10 5 S/m