Interface-engineered voltage-driven magnetic tunnel junctions with ultra-low-energy magnetization switching

TL;DR

This paper demonstrates ultra-low-energy, voltage-driven magnetization switching in magnetic tunnel junctions achieved through interface engineering with iridium doping, promising for next-generation low-power spintronic memory devices.

Contribution

The study introduces a remote doping technique to precisely control iridium concentration at the interface, enabling highly energy-efficient switching in nanoscale MTJs with high TMR.

Findings

Switching energy as low as 3.5 fJ per bit.

TMR ratio up to 160% after high-temperature annealing.

Operation in sub-nanosecond regime.

Abstract

Electric-field control of spin states offers a promising route to ultra-low-power, ultra-fast magnetization switching in spintronic devices such as magnetic tunnel junctions (MTJs). Recent progress in modulating spin-orbit interactions at the interfaces between 3d transition-metal ferromagnets and dielectric layers has underscored the role of atomic-scale heavy-metal doping in optimizing device performance. Here, we experimentally demonstrate highly energy-efficient, voltage-driven magnetization switching in MTJs exhibiting large tunnel magnetoresistance (TMR), enabled by a remote doping technique that precisely controls the iridium (Ir) concentration near the MgO-CoFeB interface in the free layer. Our devices achieve a switching energy of only 3.5 fJ per bit for nanoscale MTJs operating in the sub-nanosecond regime, while maintaining a TMR ratio up to 160 percent after 400 C post-annealing. These findings establish a viable pathway toward scalable, ultra-low-power nonvolatile memory, positioning voltage-driven MTJs as strong contenders for next-generation magnetoresistive random-access memory (MRAM) and other emerging spintronic applications.