# Decoupling Magnetic and Electric Field Control in Magneto-Ionic Materials for Energy-Efficient Brain-Inspired Memory Devices

## TL;DR

This paper introduces a new magneto-ionic material that controls magnetization using only voltage, enabling energy-efficient brain-like memory devices.

## Contribution

A novel strategy in CoFeN decouples electric and magnetic field control, eliminating the need for external magnetic fields.

## Key findings

- Voltage alone can control remnant magnetization through ion migration and magnetic interactions.
- The system mimics synaptic behaviors like potentiation and depression without magnetic fields.
- Synaptic weights depend on both electric and magnetic history after the field is removed.

## Abstract

Magneto-ionic materials, which enable nonvolatile control
of magnetism
through voltage-driven ion migration, are emerging as promising candidates
for neuromorphic computing. Unlike conventional memristors, these
systems allow dual actuation by both electric and magnetic fields,
providing a broader range of functional capabilities. The reliance
on voltage rather than current significantly reduces Joule heating
and enhances the energy efficiency. However, the general need for
external magnetic fields to modulate the voltage-induced magnetic
response remains a key limitation, undermining the full energy-saving
potential of these systems. In this work, we present a magneto-ionic
strategy in CoFeN that fully decouples the electric and magnetic field
requirements. By taking advantage of a planar N3– ion migration and the ferromagnetic exchange interactions between
preexisting and newly generated CoFe magnetic regions, we achieve
remanent-state magnetization control solely through applied voltage.
The system exhibits behaviors reminiscent of neuromorphic-inspired
functionalities, such as synaptic potentiation and depression, while
also exhibiting a cumulative voltage-driven increase in magnetization
in the absence of a magnetic field. Once the magnetic field is switched
off, synaptic weight remains influenced by both the sample’s
magnetic and electric history. By eliminating the need for magnetic
fields, our approach contributes to reduce energy consumption, offering
a more efficient pathway for brain-inspired magneto-ionic devices.