Hybrid spin Hall nano-oscillators based on ferromagnetic metal/ferrimagnetic insulator heterostructures

Spin-Hall nano-oscillators (SHNO) are one of the potential devices to achieve current controlled GHz frequency signals in nanoscale devices for neuromorphic computing and creating Ising systems. Traditional SHNO devices, which are usually made of transition metals, exhibit low emission power and high threshold current and are hard to couple from each other. Here we demonstrate a new type of hybrid SHNO based on a permalloy ferromagnetic-metal nanowire and low-damping ferrimagnetic insulator thin films of lithium aluminum ferrite. We associate the improved characteristics (e.g., a lower threshold current and higher output power) of such hybrid SHNO with the simultaneous excitation of both magnetic layers. We further find that the presence of the ferrimagnetic insulator enhances the auto-oscillation amplitude of spin-wave edge modes, consistent with our micromagnetic modeling. This hybrid SHNO expands spintronic applications, providing new means of coupling multiple SHNOs for neuromorphic computing and advancing magnonics.