Interstitial Fe-Cr alloys: Tuning of magnetism by nanoscale structural control and by implantation of nonmagnetic atoms

TL;DR

This study uses density functional theory to explore how nanoscale structural control and nonmagnetic atom implantation can tune the magnetic properties of Fe-Cr alloys, with potential applications in spintronics and durable stainless steels.

Contribution

It demonstrates that atomic relaxation creates stable configurations with enhanced magnetism, controllable by nonmagnetic impurities, advancing alloy design for magnetic applications.

Findings

Formation of stable atomic configurations with parallel Fe chains

Magnetic polarization can be externally controlled by nitrogen inclusion

Potential use in spintronic devices and durable stainless steels

Abstract

Using the density functional theory, we perform a full atomic relaxation of the bulk ferrite with 12.5%-concentration of monoatomic interstitial Cr periodically located at the edges of the bcc Fe$_\alpha$ cell. We show that structural relaxation in such artificially engineered alloys leads to significant atomic displacements and results in the formation of novel highly stable configurations with parallel chains of octahedrically arranged Fe. The enhanced magnetic polarization in the low-symmetry metallic state of this type of alloys can be externally controlled by additional inclusion of nonmagnetic impurities like nitrogen. We discuss possible applications of generated interstitial alloys in spintronic devices and propose to consider them as a basis of novel durable types of stainless steels.