Ultrafast Switching in Synthetic Antiferromagnet with Bilayer Rare-Earth Transition-Metal Ferrimagnets

TL;DR

This paper demonstrates that a bilayer amorphous FeGd ferrimagnet synthetic antiferromagnet can undergo ultrafast, subpicosecond switching via laser pulses without external magnetic fields, with potential for skyrmion control and device applications.

Contribution

It introduces a novel bilayer synthetic antiferromagnet design enabling ultrafast laser-induced switching without magnetic fields, and demonstrates skyrmion state control within this structure.

Findings

Ultrafast switching achieved in bilayer FeGd ferrimagnets using laser pulses.

Skyrmion states can be switched ultrafast in the heterostructure.

The design allows individual layer control and potential for magnetic tunnel junctions.

Abstract

In spintronics, it is important to be able to manipulate magnetization rapidly and reliably. Several methods can control magnetization, such as by applying current pulses or magnetic fields. An applied current can reverse magnetization with nanosecond speed through the spin torque effect. For faster switching, subpicosecond switching with femtoseconds laser pulse has been achieved in amorphous rare-earth transition-metal ferrimagnets. In this study, we employed atomistic simulations to investigate ultrafast switching in a synthetic antiferromagnet with bilayer amorphous FeGd ferrimagnets. Using a two-temperature model, we demonstrated ultrafast switching in this synthetic antiferromagnet without external magnetic fields. Furthermore, we showed that if we initially stabilize a skyrmion in this heterostructure, the ultrafast laser can switch the skyrmion state using the same mechanism. Furthermore, this bilayer design allows the control of each ferrimagnetic layer individually and opens the possibility for a magnetic tunnel junction.