Tailoring tunnel magnetoresistance by ultrathin Cr and Co interlayers: A first-principles investigation of Fe/MgO/Fe junctions

TL;DR

This study uses first-principles calculations to explore how ultrathin Cr and Co interlayers affect the electronic structure and tunnel magnetoresistance in Fe/MgO/Fe junctions, revealing tunable magnetic and transport properties.

Contribution

It provides a detailed ab-initio analysis of how ultrathin Cr and Co interlayers modulate TMR and electronic properties in Fe/MgO/Fe junctions, offering insights for device optimization.

Findings

Cr interlayer thickness causes oscillations in TMR ratios.

Co interlayers influence interface resonances and electronic structure.

TMR can be tailored by adjusting interlayer thickness.

Abstract

We report on systematic ab-initio investigations of Co and Cr interlayers embedded in Fe(001)/MgO/Fe(001) magnetic tunnel junctions, focusing on the changes of the electronic structure and the transport properties with interlayer thickness. The results of spin-dependent ballistic transport calculations reveal options to specifically manipulate the tunnel magnetoresistance ratio. The resistance area products and the tunnel magnetoresistance ratios show a monotonous trend with distinct oscillations as a function of the Cr thickness. These modulations are directly addressed and interpreted by means of magnetic structures in the Cr films and by complex band structure effects. The characteristics for embedded Co interlayers are considerably influenced by interface resonances which are analyzed by the local electronic structure.