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

TL;DR

This paper introduces a hybrid spin Hall nano-oscillator combining ferromagnetic metal and ferrimagnetic insulator, achieving improved oscillation properties for advanced spintronic applications like neuromorphic computing.

Contribution

The study demonstrates a novel hybrid SHNO using permalloy and lithium aluminum ferrite, enhancing auto-oscillation amplitude and spin-precession volume compared to traditional devices.

Findings

Enhanced auto-oscillation amplitude due to ferrimagnetic insulator

Larger spin-precession angles and volumes achieved

Potential for improved neuromorphic and magnonic applications

Abstract

Spin-Hall nano-oscillators (SHNOs) are promising spintronic devices to realize current controlled GHz frequency signals in nanoscale devices for neuromorphic computing and creating Ising systems. However, traditional SHNOs -- devices based on transition metals -- have high auto-oscillation threshold currents as well as low quality factors and output powers. Here we demonstrate a new type of hybrid SHNO based on a permalloy (Py) ferromagnetic-metal nanowire and low-damping ferrimagnetic insulator, in the form of epitaxial lithium aluminum ferrite (LAFO) thin films. The superior characteristics of such SHNOs are associated with the excitation of larger spin-precession angles and volumes. 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, including providing new means of coupling multiple SHNOs for neuromorphic computing and advancing magnonics.