Voltage-controlled antiferromagnetism in magnetic tunnel junctions

TL;DR

This paper reports voltage-controlled manipulation of antiferromagnetic exchange bias in magnetic tunnel junctions, enabling electric field tuning of magnetic properties via interfacial effects, with potential applications in spintronic devices.

Contribution

It introduces a novel voltage-controlled exchange bias effect in magnetic tunnel junctions through interfacial antiferromagnetism, demonstrating electric field manipulation of magnetic states.

Findings

Exchange bias field can be controlled by magnetic fields at low temperatures.

Electric field applied to MgO barrier effectively manipulates exchange bias.

Interfacial Fe(Co)Ox plays a key role in the voltage-controlled effect.

Abstract

We demonstrate a voltage-controlled exchange bias effect in CoFeB/MgO/CoFeB magnetic tunnel junctions that is related to the interfacial Fe(Co)Ox formed between the CoFeB electrodes and the MgO barrier. The unique combination of interfacial antiferromagnetism, giant tunneling magnetoresistance, and sharp switching of the perpendicularly-magnetized CoFeB allows sensitive detection of the exchange bias. It is found that the exchange bias field can be isothermally controlled by magnetic fields at low temperatures. More importantly, the exchange bias can also be effectively manipulated by the electric field applied to the MgO barrier due to the voltage-controlled antiferromagnetic anisotropy in this system.