Separating read and write units in multiferroic devices

TL;DR

This paper proposes a novel method to separate read and write units in multiferroic devices, enhancing energy efficiency and magnetoresistance by magnetically coupling nanomagnets with free layers.

Contribution

It introduces a magnetic dipole coupling approach to address material selection issues in multiferroic heterostructures, improving device performance.

Findings

Magnetic dipole coupling enables separate read/write units.

The design leads to a superior energy-delay product.

Thermal fluctuations are considered in the magnetization dynamics.

Abstract

Strain-mediated multiferroic composites, i.e., piezoelectric-magnetostrictive heterostructures, hold profound promise for energy-efficient computing in beyond Moore's law era. While reading a bit of information stored in the magnetostrictive nanomagnets using a magnetic tunnel junction (MTJ), a material selection issue crops up since magnetostrictive materials in general cannot be utilized as the free layer of the MTJ. This is an important issue since we need to achieve a high magnetoresistance for technological applications. We show here that magnetically coupling the magnetostrictive nanomagnet and the free layer e.g., utilizing the magnetic dipole coupling between them can circumvent this issue. By solving stochastic Landau-Lifshitz-Gilbert equation of magnetization dynamics in the presence of room-temperature thermal fluctuations, we show that such design can eventually lead to a superior energy-delay product.