# Spin-Orbit-Torque Driven Propagating Spin Waves

## TL;DR

This paper demonstrates that perpendicular magnetic anisotropy enables efficient generation of tunable propagating spin waves via spin-orbit torque, extending the capabilities of spin Hall nano-oscillators for nanomagnonics and neuromorphic computing.

## Contribution

It introduces a method to generate propagating spin waves using SOT in magnetic nano-constrictions with perpendicular magnetic anisotropy, surpassing previous localized modes.

## Key findings

- Propagation of spin waves achieved above the SW gap.
- Frequency of auto-oscillations is tunable by field and current.
- Extends the functionality of SHNOs for long-range data transfer.

## Abstract

Spin-orbit torque (SOT) can drive sustained spin wave (SW) auto-oscillations in a class of emerging microwave devices known as spin Hall nano-oscillators (SHNOs), which have highly non-linear properties governing robust mutual synchronization at frequencies directly amenable to high-speed neuromorphic computing. However, all demonstrations have relied on localized SW modes interacting through dipolar coupling and/or direct exchange. As nanomagnonics requires propagating SWs for data transfer, and additional computational functionality can be achieved using SW interference, SOT driven propagating SWs would be highly advantageous. Here, we demonstrate how perpendicular magnetic anisotropy can raise the frequency of SOT driven auto-oscillations in magnetic nano-constrictions well above the SW gap, resulting in the efficient generation of field and current tunable propagating SWs. Our demonstration greatly extends the functionality and design freedom of SHNOs enabling long range SOT driven SW propagation for nanomagnonics, SW logic, and neuro-morphic computing, directly compatible with CMOS technology.