Jump of tunneling magnetoresistance in magnetic nanocontacts with mismatched cross section

TL;DR

This study investigates how mismatched cross sections in magnetic nanocontacts cause a sharp decrease in tunneling magnetoresistance due to electron density distribution differences, impacting TMR device design.

Contribution

It reveals the effect of cross-sectional mismatch on TMR magnitude and explains it through electron density distribution differences, informing nanodevice design.

Findings

Sharp TMR drop with cross section mismatch

Electron density distribution differs for spin states

Design considerations for TMR-based nanodevices

Abstract

We have studied the influence of the transverse size of a magnetic tunnel nanojunction on the magnitude of the magnetoresistance. During modeling, the size of the right contact was fixed, while the size of the left one gradually changed until they coincided. We found a sharp drop in the tunneling magnetoresistance (TMR) in nanocontacts with mismatched cross section. This can be explained by the peculiarities of the spatial distribution of the electron density, which is different for majority and minority-spin states. The discovered effect must be taken into account in the design of TMR-based nanodevices.