# Simultaneous Optical and Electrical Spin-Torque Magnetometry with Stroboscopic Detection of Spin-Precession Phase

## TL;DR

This paper introduces a method for simultaneous optical and electrical detection of spin precession phases in magnetic materials, enabling detailed characterization of spin-torque phenomena for advanced spintronic applications.

## Contribution

It presents a novel stroboscopic detection technique that measures spin precession phase and local spin-torque parameters using combined optical and electrical signals.

## Key findings

- Direct measurement of spin precession phase in Permalloy ferromagnetic resonance.
- Independent determination of spin Hall angle from electrical and optical signals.
- Spatial mapping of local spin-torque parameters and phase information.

## Abstract

Spin-based coherent information processing and encoding utilize the precession phase of spins in magnetic materials. However, the detection and manipulation of spin precession phases remain a major challenge for advanced spintronic functionalities. By using simultaneous electrical and optical detection, we demonstrate the direct measurement of the precession phase of Permalloy ferromagnetic resonance driven by the spin-orbit torques from adjacent heavy metals. The spin Hall angle of the heavy metals can be independently determined from concurrent electrical and optical signals. The stroboscopic optical detection also allows spatially measuring local spin-torque parameters and the induced ferromagnetic resonance with comprehensive amplitude and phase information. Our study offers a route towards future advanced characterizations of spin-torque oscillators, magnonic circuits, and tunnelling junctions, where measuring the current-induced spin dynamics of individual nanomagnets are required.