Magnetism in Co$_{1-{\rm x}}$Fe$_{\rm x}$Sb$_{3}$ skutterudites from density functional theory

TL;DR

This study uses density functional theory and Monte Carlo simulations to explore how Fe doping induces ferromagnetism in CoSb3 skutterudites, revealing a threshold Fe concentration for magnetic order and its electronic origin.

Contribution

It provides the first detailed theoretical analysis of magnetic properties in Co$_{1-{ m x}}$Fe$_{ m x}$Sb$_{3}$, identifying the Fe concentration threshold for ferromagnetism and its electronic mechanism.

Findings

Ferromagnetism appears when Fe concentration exceeds 0.125-0.25.

Curie temperature reaches up to 70 K for FeSb$_{3}$.

Ferromagnetism is driven by a Stoner instability due to high density of states at the Fermi level.

Abstract

We have investigated the electronic and magnetic properties of Co$_{1-{\rm x}}$Fe$_{\rm x}$Sb$_{3}$ skutterudites from density functional theory and Monte Carlo simulations. We find that above a certain threshold in the Fe concentration, somewhere between x=0.125 and x=0.25, Co$_{1-{\rm x}}$Fe$_{\rm x}$Sb$_{3}$ is ferromagnetic with an atomic moment which increases asymptotically towards about 1 $\mu_{B}$/Fe and a non-zero Curie temperature which reaches 70 K for FeSb$_{3}$. Ferromagnetism is favored due to a Stoner instability in the electronic structure, where a large density of states at the Fermi-level makes it favorable to form the ferromagnetic ground state.