Our paper studying the spin wave excitation in ferromagnetic insulators by a spin Hall current is published on Physical Review B 88, 184403 (2013).
In this paper, we study a Pt|YIG bilayer structure (see the figure on the right), where a charge current J_c induces a spin Hall current J_stt, which exerts spin-transfer torque on the YIG magnetization, and excites spin waves. In this paper, we developed a self-consistent theory that takes into account the spin diffusion in Pt, and the spin wave dynamics in YIG with the spin pumping and dipole-dipole interaction considered. We found that both spin-transfer torque and spin pumping affect the surface spin wave modes strongly, and the easy-axis surface anisotropy induces a new type of surface spin wave which reduces the excitation threshold current and enhances the excitation power.
This work was carried out in collaboration with Dr. Yan Zhou from The University of Hong Kong, Dr. Hujun Jiao and Mr. Yan-ting Chen from TU Delft, as well as Prof. Gerrit Bauer from Tohoku University.