Breakdown of the resistor model of CPP-GMR in magnetic multilayered nanostructures

TL;DR

This paper investigates how the order of layers in magnetic multilayer nanostructures affects the CPP-GMR ratio, revealing that layer order influences magneto-transport properties and their disorder dependence, with effects diminishing at high disorder levels.

Contribution

It demonstrates that layer order significantly impacts CPP-GMR ratios and their disorder dependence, using a tight-binding model and Landauer-Buttiker formalism.

Findings

GMR ratio depends on layer order in multilayer structures.

Disorder sensitivity varies with layer configuration.

High disorder levels restore Boltzmann approach results.

Abstract

We study the effect on CPP GMR of changing the order of the layers in a multilayer. Using a tight-binding simple cubic two band model (s-d), magneto-transport properties are calculated in the zero-temperature, zero-bias limit, within the Landauer-Buttiker formalism. We demonstrate that for layers of different thicknesses formed from a single magnetic metal and multilayers formed from two magnetic metals, the GMR ratio and its dependence on disorder is sensitive to the order of the layers. This effect disappears in the limit of large disorder, where the results of the widely-used Boltzmann approach to transport are restored.