Real-time Hall-effect detection of current-induced magnetization dynamics in ferrimagnets

TL;DR

This paper introduces a time-resolved Hall effect measurement technique with sub-nanosecond resolution, enabling real-time investigation of current-induced magnetization dynamics in ferrimagnets, revealing distribution and delays in switching behavior.

Contribution

The authors develop a novel method for time-resolved Hall effect measurements during current pulses, allowing real-time analysis of magnetization reversal in ferrimagnets, which was not previously possible.

Findings

Current-induced switching in GdFeCo is temporally distributed with delays.

Switching speed is limited by activation delays despite high domain-wall velocity.

The technique can be applied to various current-induced phenomena and combined with other excitations.

Abstract

Measurements of the transverse Hall resistance are widely used to investigate electron transport, magnetization phenomena, and topological quantum states. Owing to the difficulty of probing transient changes of the transverse resistance, the vast majority of Hall effect experiments are carried out in stationary conditions using either dc or ac currents. Here we present an approach to perform time-resolved measurements of the transient Hall resistance during current-pulse injection with sub-nanosecond temporal resolution. We apply this technique to investigate in real-time the magnetization reversal caused by spin-orbit torques in ferrimagnetic GdFeCo dots. Single-shot Hall effect measurements show that the current-induced switching of GdFeCo is widely distributed in time and characterized by significant activation delays, which limit the total switching speed despite the high domain-wall velocity typical of ferrimagnets. Our method applies to a broad range of current-induced phenomena and can be combined with non-electrical excitations to perform pump-probe Hall effect measurements.