Spin waves in insulating materials such as Yttrium Iron Garnet (YIG) can be used for signal propagation and processing using the spin of the electrons rather than transport of their charge. Planar YIG films can be integrated with silicon technology to realize devices such as tunable filters, frequency selective limiters, and signal-to-noise enhancers. However, such films suffer from spin-wave damping, which limits their use in such applications. Here, we show that spin currents in topological insulators (TI) can be used to reduce spin-wave damping. TI supports surface spin currents, potentially making it an efficient source of antidamping torque. We show that in a YIG/Bi2Se3 bilayer, the spin-wave damping rate can be reduced by 60% at a current density of 8×105A/cm2. Furthermore, we show that the damping reduction has a strong dependence on spin-wave frequency and we demonstrate that this dependence arises from nonlinear magnon scattering.
ASJC Scopus subject areas
- Physics and Astronomy(all)