Spin dynamics of FeGa$_{3-x}$Ge$_x$ studied by Electron Spin Resonance

TL;DR

This study investigates how electron doping via Ge substitution influences the spin dynamics and emergence of itinerant ferromagnetism in FeGa$_{3-x}$Ge$_x$ using Electron Spin Resonance, revealing the evolution of magnetic properties.

Contribution

It provides the first ESR analysis of FeGa$_{3-x}$Ge$_x$, demonstrating ESR as an effective method to study itinerant magnetism in doped intermetallic semiconductors.

Findings

ESR signal indicates pre-formed magnetic moments in undoped FeGa$_{3}$

Itinerant magnetism affects ESR properties below 40 K with Ge doping

High-temperature ESR signal remains unchanged regardless of Ge content

Abstract

The intermetallic semiconductor FeGa$_{3}$ acquires itinerant ferromagnetism upon electron doping by a partial replacement of Ga with Ge. We studied the electron spin resonance (ESR) of high-quality single crystals of FeGa$_{3-x}$Ge$_x$ for $x$ from 0 up to 0.162 where ferromagnetic order is observed. For $x = 0$ we observed a well-defined ESR signal, indicating the presence of pre-formed magnetic moments in the semiconducting phase. Upon Ge doping the occurrence of itinerant magnetism clearly affects the ESR properties below $\approx 40$~K whereas at higher temperatures an ESR signal as seen in FeGa$_{3}$ prevails independent on the Ge-content. The present results show that the ESR of FeGa$_{3-x}$Ge$_x$ is an appropriate and direct tool to investigate the evolution of 3d-based itinerant magnetism.