Efficient All-Optical Helicity Dependent Switching of Spins in a Pt/Co/Pt Film by a Dual-Pulse Excitation

Kihiro T Yamada,Sergey Semin,Theo Rasing,Sergiu Ruta,Andrei Kirilyuk,Fuyuki Ando,Alexey V Kimel,Tian Li,Teruo Ono,Kiran Horabail Prabhakara

doi:10.3389/fnano.2022.765848

Abstract

All-optical helicity dependent switching (AO-HDS), deterministic control of magnetization by circularly polarized laser pulses, allows to efficiently manipulate spins without the need of a magnetic field. However, AO-HDS in ferromagnetic metals so far requires many laser pulses for fully switching their magnetic states. Using a combination of a short, 90-fs linearly polarized pulse and a subsequent longer, 3-ps circularly polarized pulse, we demonstrate that the number of pulses for full magnetization reversal can be reduced to four pulse pairs in a single stack of Pt/Co/Pt. The obtained results suggest that the dual-pulse approach is a potential route towards realizing efficient AO-HDS in ferromagnetic metals.

Highlights

IntroductionThe explosive growth of big data and artificial intelligence demands faster and more energyefficient ways to manipulate and store data (Beyond CMOS, 2018; Manipatruni et al, 2018; Dieny et al, 2020)
Pt/Co/Pt systems are relevant for testing the dual-pulse approach because they are typical candidates for spintronic devices (Brataas et al, 2012) as well as for all-optical helicity dependent switching (Lambert et al, 2014; Hadri et al, 2016a; Hadri et al, 2016b; Medapalli et al, 2017; Parlak et al, 2018; Quessab et al, 2018; Chakravarty et al, 2019; Kichin et al, 2019; Cheng et al, 2020)
We have demonstrated that a dual-pulse method can drastically reduce the pulse number required for All-optical helicity dependent switching (AO-HDS) in a Pt/Co/Pt multilayer

Summary

Introduction

The explosive growth of big data and artificial intelligence demands faster and more energyefficient ways to manipulate and store data (Beyond CMOS, 2018; Manipatruni et al, 2018; Dieny et al, 2020). One approach is to use current-induced torque (Brataas et al, 2012; Dieny et al, 2020) to switch magnetization, as in spin-transfer torque magnetic random access memories (Apalkov et al, 2016). Another potential route is to use an ultrashort laser pulse (Kirilyuk et al, 2010; Kimel and Li., 2019). Even though the leading part of all-optical magnetization switching has been ferrimagnets, represented by GdFeCo (Stanciu et al, 2007; Vahaplar et al, 2009; Ostler et al, 2011; Radu et al, 2011; Khorsand et al, 2012; Mangin et al, 2014), cutting-edge magnetic media consist of ferromagnets (Kryder et al, 2008; Apalkov et al, 2016) This is the reason why alloptical switching in ferromagnets attracts great attention. AO-HDS generally requires at least tens and usually hundreds of laser pulses for full switching (Kichin et al, 2019)

Objectives

Methods

Results

Discussion

Conclusion