An invisible non-volatile solid-state memory

TL;DR

This paper introduces a novel non-volatile solid-state memory that uses electric control of magnetic states in FeRh heterostructures, offering high stability, low energy use, and resistance to external magnetic perturbations.

Contribution

It demonstrates electrically controlled switching between ferromagnetic and antiferromagnetic states in FeRh, enabling a stable, non-volatile, magnetoelectric memory device.

Findings

Electric fields can toggle magnetic states in FeRh heterostructures.

The memory states are stable and insensitive to external magnetic fields.

The device operates with low energy dissipation.

Abstract

Information technologies require entangling data stability with encryption for a next generation of secure data storage. Current magnetic memories, ranging from low-density stripes up to high-density hard drives, can ultimately be detected using routinely available probes or manipulated by external magnetic perturbations. Antiferromagnetic resistors feature unrivalled robustness but the stable resistive states reported scarcely differ by more than a fraction of a percent at room temperature. Here we show that the metamagnetic (ferromagnetic to antiferromagnetic) transition in intermetallic Fe0.50Rh0.50 can be electrically controlled in a magnetoelectric heterostructure to reveal or cloak a given ferromagnetic state. From an aligned ferromagnetic phase, magnetic states are frozen into the antiferromagnetic phase by the application of an electric field, thus eliminating the stray field and likewise making it insensitive to external magnetic field. Application of a reverse electric field reverts the antiferromagnetic state to the original ferromagnetic state. Our work demonstrates the building blocks of a feasible, extremely stable, non-volatile, electrically addressable, low-energy dissipation, magnetoelectric multiferroic memory.