Micromagnetic study of electrical-field-assisted magnetization switching in MTJ devices

TL;DR

This paper presents a comprehensive micromagnetic analysis of electric-field-assisted magnetization switching in MgO-based MTJ devices, revealing complex nucleation processes like vortex formation that enable lower current densities.

Contribution

It provides the first full micromagnetic simulation of electric-field-assisted switching, extending beyond previous macrospin models and demonstrating complex nucleation mechanisms.

Findings

Switching involves complex nucleation, including vortex formation.

Electric-field assistance enables lower switching current densities.

Micromagnetic simulations reveal detailed switching dynamics.

Abstract

Perpendicular MgO-based Magnetic Tunnel Junctions are optimal candidates as building block of Spin Transfer Torque (STT) magnetoresistive memories. However, up to now, the only STT is not enough to achieve switching current density below 106 A/cm2. A recent work [Wang et al., Nature Mater., vol. 11, pp 64-68, Jan. 2012] has experimentally demonstrated the possibility to perform magnetization switching assisted by an electric-field at ultra-low current density. Theoretically, this switching has been studied by using a macrospin approach only. Here, we show a full micromagnetic study. We found that the switching occurs via a complex nucleation process including the nucleation of magnetic vortexes.