Single-shot multi-level all-optical magnetization switching mediated by spin-polarized hot electron transport

TL;DR

This paper demonstrates a novel single-pulse all-optical magnetization switching method in multilayer magnetic structures, utilizing spin-polarized hot electrons to deterministically control magnetic states for potential ultrafast data storage applications.

Contribution

It introduces a new approach for single-pulse all-optical switching of ferromagnetic layers mediated by spin-polarized hot electrons in multilayer structures, expanding beyond GdFeCo-based materials.

Findings

Successful single-pulse switching of Co/Pt multilayers.

Control of magnetic states via spin-polarized hot electrons.

Potential for multi-bit optical magnetic recording.

Abstract

All-optical ultrafast magnetization switching in magnetic material thin film without the assistance of an applied external magnetic field is being explored for future ultrafast and energy-efficient magnetic storage and memories. It has been shown that femto-second light pulses induce magnetization reversal in a large variety of magnetic materials. However, so far, only GdFeCo-based ferrimagnetic thin films exhibit magnetization switching via a single optical pulse. Here we demonstrate the single-pulse switching of Co/Pt multilayers within a magnetic spin-valve structure ([Co/Pt] / Cu / GdFeCo) and further show that the four possible magnetic configurations of the spin valve can be accessed using a sequence of single femto-second light pulses. Our experimental study reveals that the magnetization final state of the ferromagnetic [Co/Pt] layer is determined by spin-polarized hot electrons generated by the light pulse interactions with the GdFeCo layer. This work provides a new approach to deterministically switch ferromagnetic layers and a pathway to engineering materials for opto-magnetic multi-bit recording.