Effect of Diffused Hydrogen on the Conductance of Fe/Mgo/Fe Magnetic Tunnel Junctions: Atomistic Simulation

TL;DR

This study uses atomistic simulations to show how hydrogen diffusion during fabrication distorts MgO barrier symmetry in Fe/MgO/Fe magnetic tunnel junctions, significantly reducing conductance and TMR.

Contribution

It provides a detailed atomistic analysis of hydrogen's detrimental impact on conductance and TMR in magnetic tunnel junctions using first-principles calculations.

Findings

Hydrogen diffusion distorts delta 1 symmetry in MgO.

Distortion reduces conductance and TMR.

Improved fabrication methods can mitigate these effects.

Abstract

In this work we have analysed the deterimental effect on conductance caused by diffusion of hydrogen atoms in interstitial voids during fabrication process of magnesium oxide barrier of an Fe MgO Fe magnetic tunnel junction, using first principle calculations. This diffusion of hydrogen atoms in interstitial voids in barrier disturbs a certain kind of symmetry possessed by magnesium oxide often termed as delta 1 state symmetry. Distortion in delta 1 state symmetry tempers the condutance through the magnetic tunnel junction specially in parallel configuration, which in turn reduces the Tunnelling Magneto Resistance TMR to large extent. Improved methods of fabrication can be used to counter such kind of problems which affect device operation.