RKKY interaction between extended magnetic defect lines in graphene

TL;DR

This paper investigates how the RKKY interaction in graphene changes when magnetic impurities are extended into lines, revealing increased interaction range and reduced effective dimensionality, with implications for spintronic devices.

Contribution

It introduces a combined analytic and numerical approach to study the impact of defect dimensionality on RKKY interactions in graphene, highlighting the effects of extended impurity lines.

Findings

Extended impurity lines increase the interaction range.

Moving from point impurities to lines reduces effective dimensionality.

Results suggest enhanced spintronic device performance.

Abstract

Of fundamental interest in the field of spintronics is the mechanism of indirect exchange coupling between magnetic impurities embedded in metallic hosts. A range of physical features, such as magnetotransport and overall magnetic moment formation, are predicated upon this magnetic coupling, often referred to as the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. Recent theoretical studies on the RKKY in graphene have been motivated by possible spintronic applications of magnetically doped graphene systems. In this work a combination of analytic and numerical techniques are used to examine the effects of defect dimensionality on such an interaction. We show, in a mathematically transparent manner, that moving from single magnetic impurities to extended lines of impurities effectively reduces the dimensionality of the system and increases the range of the interaction. This has important consequences for the spintronic application of magnetically-doped and we illustrate this with a simple magnetoresistance device.