Spin mixing conductance in Cu-Ir dilute alloys

We have investigated the spin mixing conductance at the interface of Py and Cu-Ir dilute alloys by means of spin pumping and inverse spin Hall effect (ISHE) measurements for Cu-Ir. From systematic studies of the effective spin mixing conductance as a function of Ir concentration, we found that the interfacial spin mixing conductance g↑↓ was proportional to the Ir concentration. This result is consistent with a scenario based on the impurity-dependent density of states at the Fermi energy. From the ISHE measurements as a function of Ir concentration, we show that the mechanism of the spin Hall effect is skew scattering and that the spin Hall angle is comparable to the previously determined value by using the lateral spin valve structures.