Inverse spin Hall effect in ITO/YIG exited by spin pumping and spin Seebeck experiments

Spin currents, which are excited in indium tin oxide (ITO)/yttrium iron garnet (YIG) by the methods of spin pumping and spin Seebeck effect, are investigated through the inverse spin Hall effect (ISHE). It is demonstrated that the ISHE voltage can be generated in ITO by spin pumping under both in-plane and out-of-plane magnetization configurations. Moreover, it is observed that the enhancement of spin Hall angle and interfacial spin mixing conductance can be achieved by an appropriate annealing process. However, the ISHE voltage is hardly seen in the presence of a longitudinal temperature gradient. The absence of the longitudinal spin Seebeck effect can be ascribed to the almost equal thermal conductivity of ITO and YIG and specific interface structure, or to the large negative temperature dependent spin mixing conductance.