Extending the scope and understanding of all-optical magnetization switching in Gd-based alloys by controlling the underlying temperature transients

TL;DR

This study investigates how controlling temperature transients via Cu layer thickness influences all-optical magnetization switching in Gd-based alloys, revealing limits set by multi-domain formation and demonstrating continuous reversal in specific compositions.

Contribution

It introduces a method to control temperature transients through Cu layer thickness to enhance understanding of all-optical switching in Gd alloys, highlighting the role of multi-domain formation.

Findings

Increasing Cu thickness enlarges multi-domain formation thresholds.

Multi-domain formation limits maximum fluence and pulse duration for switching.

Continuous magnetization reversal occurs before multi-domain formation in certain alloys.

Abstract

We use the thickness of Cu layers to control all-optical switching of magnetization in adjacent Gd$_{24}$(Fe$_9$0Co$_{10}$)$_{76}$ films. While increasing the Cu thickness from 5 to 900nm has no effect on the switching threshold, it significantly enlarges the fluence and pulse duration at which multiple domains emerge. Having shown that thermally activated multi-domain formation limits the maximum fluence and pulse duration for controlled switching, we demonstrate that continuous magnetization reversal precedes multi-domain formation in Gd$_{18}$Dy$_4$Co$_{78}$ films excited with fluences slightly larger than the multi-domain threshold.