Enhancing All-Optical Switching of Magnetization by He Ion Irradiation

TL;DR

This paper demonstrates that He ion irradiation enhances all-optical switching in Co/Gd ferrimagnets by intermixing layers, reducing the energy threshold and enabling improved control for spintronic applications.

Contribution

It introduces a novel method of using He ion irradiation to enhance AOS in synthetic ferrimagnets by interfacial intermixing, supported by simulations and experiments.

Findings

AOS threshold fluence reduced by nearly 30% with He ion irradiation.

Intermixing of magnetic layers verified both experimentally and through simulations.

He ion irradiation provides a controllable way to engineer AOS properties.

Abstract

All-optical switching (AOS) of magnetization by a single femtosecond laser pulse in Co/Gd based synthetic ferrimagnets is the fastest magnetization switching process. On the other hand, He ion irradiation has become a promising tool for interface engineering of spintronic material platforms, giving rise to significant modification of magnetic properties. In this paper, we explore the use of He ion irradiation to enhance single pulse AOS of Co/Gd bilayer-based synthetic ferrimagnets. The intermixing of the constituent magnetic layers by He ion irradiation was both numerically simulated and experimentally verified. We theoretically modelled the effects of intermixing on AOS using the layered microscopic 3-temperature model and found that AOS is enhanced significantly by breaking the pristine Co/Gd interface through intermixing. Following this notion, we studied the threshold fluence of AOS as a function of He ion irradiation fluence. We found that the AOS threshold fluence can be reduced by almost 30%. Our study reveals the control of AOS by He ion irradiation, which opens up an industrially compatible approach for local AOS engineering.