Single-shot optical precessional magnetization switching of Pt/Co/Pt ferromagnetic trilayers

TL;DR

This paper demonstrates single-shot optical magnetization switching in Pt/Co/Pt ferromagnetic trilayers using femtosecond laser pulses and magnetic fields, with insights from simulations and material modifications to enable faster and broader applicability.

Contribution

It introduces a method for optical magnetization switching in ferromagnetic trilayers and explores material modifications to enhance switching speed and control.

Findings

Switching occurs within a specific laser power window.

Adding a Cu layer accelerates anisotropy re-establishment.

Thermal anisotropy torque influences the switching process.

Abstract

Ultra-fast magnetization switching triggered by a single femtosecond laser pulse has gained significant attention over the last decade for its potential in low-power consumption, high-speed memory applications. However, this phenomenon has been primarily observed in Gd-based ferrimagnetic materials, which are unsuitable for storage due to their weak perpendicular magnetic anisotropy (PMA). In this work, we demonstrated that applying a single laser pulse and an in-plane magnetic field can facilitate magnetic switching in a Pt/Co/Pt ferromagnetic trilayers stack within a specific laser power window. To further understand this phenomenon, we introduce a Cu layer to accelerates the re-establishment time of the anisotropy field of Pt/Co/Pt trilayers, which leads to bullseye-patterned magnetic switching. We have mapped state diagrams for these phenomena, and through micromagnetic simulations, we have determined that these switchings are influenced by thermal anisotropy torque, which can be modulated through PMA. These findings indicate that single-shot optical precessional magnetization reversal is feasible in a broader range of materials, opening avenues for the development of optical-magnetic memory devices.