Energy-efficient domain wall motion governed by the interplay of helicity-dependent optical effect and spin-orbit torque

TL;DR

This paper demonstrates a method to reduce the current density needed for domain wall motion in magnetic wires by combining helicity-dependent optical effects with spin-orbit torque, enabling low-power spintronic devices.

Contribution

It introduces a novel approach combining optical helicity effects with spin-orbit torque to control domain walls, reducing power consumption in spintronic devices.

Findings

Helicity-dependent domain wall motion can be achieved with laser pulses.

Threshold current density is reduced by over 50%.

An optoelectronic logic-in-memory device was demonstrated.

Abstract

Spin-orbit torque provides a powerful means of manipulating domain walls along magnetic wires. However, the current density required for domain wall motion is still too high to realize low power devices. Here we experimentally demonstrate helicity-dependent domain wall motion by combining synchronized femtosecond laser pulses and short current pulses in Co/Ni/Co ultra-thin film wires with perpendicular magnetization. Domain wall can remain pinned under one laser circular helicity while depinned by the opposite circular helicity. Thanks to the all-optical helicity-dependent effect, the threshold current density due to spin-orbit torque can be reduced by more than 50%. Based on this joint effect combining spin-orbit torque and helicity-dependent laser pulses, an optoelectronic logic-in-memory device has been experimentally demonstrated. This work enables a new class of low power spintronic-photonic devices beyond the conventional approach of all-optical switching or all-current switching for data storage.