First-principle study of spin transport property in $L1_0$-FePd(001)/graphene heterojunction

TL;DR

This study uses first-principles calculations to analyze spin transport in FePd/graphene heterojunctions, revealing high magnetoresistance ratios and robustness to interface displacements, advancing spintronics device design.

Contribution

It provides the first detailed theoretical prediction of spin-dependent transport properties in multilayer graphene-based FePd heterojunctions, highlighting their potential for spintronics applications.

Findings

Magnetoresistance ratio of 150-200% predicted.

Transport behavior shifts from tunneling to graphite $ ext{π}$-band with more graphene layers.

Spin transport remains robust despite interface displacements.

Abstract

In our previous work, we synthesized a metal/2D material heterointerface consisting of $L1_0$-ordered iron-palladium (FePd) and graphene (Gr) called FePd(001)/Gr. This system has been explored by both experimental measurements and theoretical calculations. In this study, we focus on a heterojunction composed of FePd and multilayer graphene referred to as FePd(001)/$m$-Gr/FePd(001), where $m$ represents the number of graphene layers. We perform first-principles calculations to predict their spin-dependent transport properties. The quantitative calculations of spin-resolved conductance and magnetoresistance (MR) ratio (150-200%) suggest that the proposed structure can function as a magnetic tunnel junction in spintronics applications. We also find that an increase in $m$ not only reduces conductance but also changes transport properties from the tunneling behavior to the graphite $\pi$-band-like behavior. Additionally, we investigate the spin-transfer torque-induced magnetization switching behavior of our \color{blue} junction structures \color{black} using micromagnetic simulations. Furthermore, we examine the impact of lateral displacements (``sliding'') at the interface and find that the spin transport properties remain robust despite these changes; this is the advantage of two-dimensional material hetero-interfaces over traditional insulating barrier layers such as MgO.