Ab-initio-calculations of the GMR-effect in Fe/V multilayers

TL;DR

This paper uses ab-initio calculations to analyze how different types of atomic disorder in Fe/V multilayers affect the giant magnetoresistance (GMR) effect, revealing cases of enhancement, reduction, and even inverse GMR.

Contribution

It introduces a self-consistent semi-empirical ab-initio approach to evaluate GMR in disordered multilayers with various impurity configurations.

Findings

Disorder can enhance or reduce GMR depending on impurity distribution.

Maximum GMR occurs with specific small group substitutions.

Inverse GMR observed with certain V atom substitutions.

Abstract

In a self-consistent semi-empirical numerical approach based on ab-initio-calculations for small samples, we evaluate the GMR effect for disordered (001)-(3--Fe/3--V)$_\infty$ multilayers by means of a Kubo formalism. We consider four different types of disorder arrangements: In case (i) and (ii), the disorder consists in the random interchange of some Fe and V atoms, respectively, at interface layers; in case (iii) in the formation of small groups of three substitutional Fe atoms in a V interface layer and a similar V group in a Fe layer at a different interface; and for case (iv) in the substitution of some V atoms in the innermost V layers by Fe. For cases (i) and (ii), depending on the distribution of the impurities, the GMR effect is enhanced or reduced by increasing disorder, in case (iii) the GMR effect is highest, whereas finally, in case (iv), a negative GMR is obtained (''inverse GMR'').