Anisotropic MagnetoMemristance

TL;DR

This paper introduces anisotropic magneto-memristance (AMM), a durable, GHz-frequency memristive effect in ferromagnetic layers driven by current-induced torque and anisotropic magnetoresistance, promising advancements in magnetic memory devices.

Contribution

It demonstrates the emergence of GHz-range memristance in single ferromagnetic layers through analytical and numerical methods, linking it to magnetization topology.

Findings

Single-layer ferromagnetic devices can exhibit GHz memristance.

The effect is driven by Zhang-Li torque and anisotropic magnetoresistance.

Micromagnetic simulations confirm analytical predictions.

Abstract

In the last decade, nanoscale resistive devices with memory have been the subject of intense study because of their possible use in brain-inspired computing. However, operational endurance is one of the limiting factors in the adoption of such technology. For this reason, we discuss the emergence of current-induced memristance in magnetic materials, known for their durability. We show analytically and numerically that a single ferromagnetic layer can possess GHz memristance, due to a combination of two factors: a current-induced transfer of angular momentum (Zhang-Li torque) and the anisotropic magnetoresistance (AMR). We term the resulting effect the anisotropic magneto-memristance (AMM). We connect the AMM to the topology of the magnetization state, within a simple model of a 1-dimensional annulus-shaped magnetic layer, confirming the analytical results with micromagnetic simulations for permalloy. Our results open a new path towards the realization of single-layer magnetic memristive devices operating at GHz frequencies.