Influence of Roughness and Disorder on Tunneling Magnetoresistance

TL;DR

This study quantitatively examines how interface roughness and disorder influence the tunneling magnetoresistance in FeCo vacuum magnetic tunnel junctions, revealing significant effects on spin transport and TMR.

Contribution

It provides a parameter-free electronic structure analysis of how roughness and disorder affect TMR in magnetic tunnel junctions, highlighting their impact.

Findings

Surface roughness strongly reduces TMR.

Disorder in leads also suppresses TMR, but less than roughness.

Ideal systems predict high TMR, but real imperfections diminish this.

Abstract

A systematic, quantitative study of the effect of interface roughness and disorder on the magnetoresistance of FeCo$|$vacuum$|$FeCo magnetic tunnel junctions is presented based upon parameter-free electronic structure calculations. Surface roughness is found to have a very strong effect on the spin-polarized transport while that of disorder in the leads (leads consisting of a substitutional alloy) is weaker but still sufficient to suppress the huge tunneling magneto-resistance (TMR) predicted for ideal systems.