Tunnel magnetoresistance in scandium nitride magnetic tunnel junctions using first principles

TL;DR

This paper investigates scandium nitride as a potential tunnel barrier in magnetic tunnel junctions, demonstrating high tunnel magnetoresistance and low resistance-area product through first-principles simulations, offering a promising alternative to magnesium oxide.

Contribution

It introduces scandium nitride as a novel tunnel barrier material with advantageous properties for magnetic tunnel junctions, addressing variability and high current challenges.

Findings

High tunnel magnetoresistance via symmetry filtering

Low wavefunction decay rates in Fe/ScN/Fe junctions

Potential for reduced device variability and degradation

Abstract

The magnetic tunnel junction is a cornerstone of spintronic devices and circuits, providing the main way to convert between magnetic and electrical information. In state-of-the-art magnetic tunnel junctions, magnesium oxide is used as the tunnel barrier between magnetic electrodes, providing a uniquely large tunnel magnetoresistance at room temperature. However, the wide bandgap and band alignment of magnesium oxide-iron systems increases the resistance-area product and causes challenges of device-to-device variability and tunnel barrier degradation under high current. Here, we study using first principles narrower-bandgap scandium nitride tunneling properties and transport in magnetic tunnel junctions in comparison to magnesium oxide. These simulations demonstrate a high tunnel magnetoresistance in Fe/ScN/Fe MTJs via {\Delta}_1 and {\Delta}_2' symmetry filtering with low wavefunction decay rates, allowing a low resistance-area product. The results show that scandium nitride could be a new tunnel barrier material for magnetic tunnel junction devices to overcome variability and current-injection challenges.