Origin of low-temperature magnetic ordering in Ga1-xMnxN

TL;DR

This study investigates the low-temperature magnetic ordering in Ga1-xMnxN using advanced magnetometry, theoretical modeling, and simulations to understand the magnetic interactions and validate computational methods.

Contribution

It provides detailed experimental data on Curie temperatures and interprets these results through theoretical and simulation frameworks, advancing understanding of magnetic interactions in dilute magnetic insulators.

Findings

Curie temperature varies with Mn concentration

Ferromagnetic superexchange identified as key interaction

Benchmarking of ab initio methods against experimental data

Abstract

By employing highly sensitive millikelvin SQUID magnetometry, the magnitude of the Curie temperature as a function of the Mn concentration x is determined for thoroughly characterized Ga1-xMnxN. The interpretation of the results in the frame of tight binding theory and of Monte Carlo simulations, allows us to assign the spin interaction to ferromagnetic superexchange and to benchmark the accuracy of state-of-the-art ab initio methods in predicting the magnetic characteristics of dilute magnetic insulators.