Interlayer exchange coupling modulated all-optical magnetic switching in synthetic ferrimagnetic heterostructures

Abstract

All-optical magnetic switching in ferromagnetic thin films reveals an unprecedented route to manipulate magnetic configurations for future ultrafast and energy-efficient magnetic storage. In this study, the relationship between the all-optical magnetic switching and interlayer exchange coupling was investigated in a [Co/Pt]n/Ru/GdFeCo synthetic ferrimagnetic heterostructure. While a thermal demagnetization is dominant in a single GdFeCo alloy film after laser sweep, the magneto-optical interaction transits to a clear all-optical magnetic switching after GdFeCo film being exchange coupled with a [Co/Pt]n multilayer. Meanwhile, the established interlayer exchange coupling can also significantly increase the optical-induced magnetization switching ratio in [Co/Pt]n multilayer after single-pulse laser illumination. A threshold interlayer exchange coupling strength of ∼0.31 erg cm−2 was confirmed for achieving a deterministic (∼90%) optical-induced magnetization switching ratio after multi-pulse laser illumination. This study demonstrates a clear correlation between interlayer exchange coupling and all-optical magnetic switching, offering a promising engineering pathway for high density all-optical magnetic recording.