Ultrafast racetrack based on compensated Co/Gd-based synthetic ferrimagnet with all-optical switching

TL;DR

This paper demonstrates a synthetic ferrimagnetic multilayer system that enables ultrafast, energy-efficient all-optical switching and high-velocity domain wall motion, promising for advanced memory and logic devices.

Contribution

It introduces a [Co/Gd/Co/Gd] multilayer system that achieves both fast current-induced domain wall motion and all-optical switching across its composition range.

Findings

Domain wall velocities over 2000 m/s at room temperature

AOS present in full composition range of the multilayer

Transient Joule heating modeling explains CIDWM behavior

Abstract

Spin-orbitronics and single pulse all-optical switching (AOS) of magnetization are two major successes of the rapidly advancing field of nanomagnetism in recent years, with high potential for enabling novel, fast and energy-efficient memory and logic platforms. Fast current-induced domain wall motion (CIDWM) and single shot AOS have been individually demonstrated in different ferrimagnetic alloys. However, the stringent requirement for their composition control makes these alloys challenging materials for wafer-scale production. Here, we simultaneously demonstrate fast CIDWM and energy efficient AOS in a synthetic ferrimagnetic system based on multilayered [Co/Gd/Co/Gd]. We firstly show that AOS is present in its full composition range. We find that current-driven domain wall velocities over 2000 m/s at room temperature, achieved by compensating the total angular momentum through layer thickness tuning. Furthermore, analytical modeling of the CIDWM reveals that Joule heating needs to be treated transiently to properly describe the CIDWM for our sub-ns current pulses. Our studies establish [Co/Gd]-based synthetic ferrimagnets to be a unique materials platform for domain wall devices with access to ultrafast single pulse AOS.