Control of field- and current-driven magnetic domain wall motion by exchange-bias in Cr2O3/Co/Pt trilayers

TL;DR

This study demonstrates how exchange bias in Cr2O3/Co/Pt trilayers can effectively control magnetic domain wall motion driven by fields and currents, enabling potential advancements in spintronic device switching.

Contribution

It reveals the influence of exchange bias orientation on domain wall dynamics and shows stable control under high fields and current densities, advancing magnetic memory technology.

Findings

Exchange bias direction affects domain wall velocity and propagation.

Exchange bias remains stable under high external fields and current pulses.

Zero-field domain wall velocity can be modified by a factor of ten.

Abstract

We investigate the motion of magnetic domain walls driven by magnetic fields and current-driven spin-orbit torques in an exchange-biased system with perpendicular magnetization. We consider Cr2O3/Co/Pt trilayers as model system, in which the magnetization of the Co layer can be exchanged-biased out-of-plane or in-plane depending on the field cooling direction. In field-driven experiments, the in-plane exchange bias favors the propagation of the domain walls with internal magnetization parallel to the exchange bias field. In current-driven experiments, the domain walls propagate along the current direction, but the domain wall velocity increases and decreases symmetrically (anti-symmetrically) for both current polarities when the exchange bias is parallel (perpendicular) to the current line. At zero external field, the exchange bias modifies the velocity of current-driven domain wall motion by a factor of ten. We also find that the exchange bias remains stable under external fields up to 15 kOe and ns-long current pulses with current density up to 3.5x10^12 A/m^2. Our results demonstrate versatile control of the domain wall motion by exchange bias, which is relevant to achieve field-free switching of the magnetization in perpendicular systems and current-driven manipulation of domain walls velocity in spintronic devices.