Ab initio exchange interactions and magnetic properties of Gd2Fe17 iron sublattice: rhombohedral vs. hexagonal phases

TL;DR

This study uses ab initio calculations to analyze the electronic structure and magnetic interactions in Gd2Fe17, revealing phase-dependent exchange interactions and accurately predicting Curie temperatures and magnetic moments.

Contribution

It provides the first ab initio determination of exchange interactions in Gd2Fe17 for both rhombohedral and hexagonal phases, linking electronic structure to magnetic properties.

Findings

Ferromagnetic direct exchange in first coordination sphere

Antiferromagnetic indirect exchange in second coordination sphere

Calculated Curie temperatures match experimental data

Abstract

In the framework of the LSDA+U method electronic structure and magnetic properties of the intermetallic compound Gd2Fe17 for both rhombohedral and hexagonal phases have been calculated. On top of that, ab initio exchange interaction parameters within the Fe sublattice for all present nearest and some next nearest Fe ions have been obtained. It was found that for the first coordination sphere direct exchange interaction is ferromagnetic. For the second coordination sphere indirect exchange interaction is observed to be weaker and of antiferromagnetic type. Employing the theoretical values of exchange parameters Curie temperatures Tc of both hexagonal and rhombohedral phases of Gd2Fe17 within Weiss mean-field theory were estimated. Obtained values of Tc and its increase going from the hexagonal to rhombohedral crystal structure of Gd2Fe17 agree well with experiment. Also for both structures LSDA+U computed values of total magnetic moment coincide with experimental ones.