Emergence of competing magnetic interactions induced by Ge doping in the semiconductor FeGa3

TL;DR

This study investigates how Ge doping alters the magnetic properties of FeGa3, revealing a transition from diamagnetic to ferromagnetic states and the influence of dopant distribution on magnetic interactions.

Contribution

It combines theoretical and experimental approaches to elucidate the magnetic evolution in Ge-doped FeGa3, highlighting the role of dopant concentration and distribution.

Findings

Localized magnetic moments at low Ge concentrations

Emergence of delocalized magnetic behavior with increased doping

Dopant distribution influences magnetic interactions, including antiferromagnetism

Abstract

FeGa$_3$ is an unusual intermetallic semiconductor that presents intriguing magnetic responses to the tuning of its electronic properties. When doped with Ge, the system evolves from diamagnetic to paramagnetic to ferromagnetic ground states that are not well understood. In this work, we have performed a joint theoretical and experimental study of FeGa$_{3-x}$Ge$_x$ using Density Functional Theory and magnetic susceptibility measurements. For low Ge concentrations we observe the formation of localized moments on some Fe atoms and, as the dopant concentration increases, a more delocalized magnetic behavior emerges. The magnetic configuration strongly depends on the dopant distribution, leading even to the appearance of antiferromagnetic interactions in certain configurations.