Magnetic bond-order potential for iron-cobalt alloys

TL;DR

This paper introduces a new analytic bond-order potential for iron-cobalt alloys that accurately models magnetic and structural properties, enabling large-scale atomistic simulations with high efficiency.

Contribution

The paper presents a novel bond-order potential fitted to DFT data, capturing magnetic effects and phase stability in Fe-Co alloys for large-scale simulations.

Findings

Accurately predicts structural stability and elastic constants.

Reproduces DFT phase stability and magnetic effects.

Suitable for simulations with millions of atoms.

Abstract

For large-scale atomistic simulations of magnetic materials, the interplay of atomic and magnetic degrees of freedom needs to be described with high computational efficiency. Here we present an analytic bond-order potential (BOP) for iron-cobalt, an interatomic potential based on a coarse-grained description of the electronic structure. We fitted BOP parameters to magnetic and non-magnetic density-functional theory (DFT) calculations of Fe, Co, and Fe-Co bulk phases. Our BOP captures the electronic structure of magnetic and non-magnetic Fe-Co phases. It provides accurate predictions of structural stability, elastic constants, phonons, point and planar defects, and structural transformations. It also reproduces the DFT-predicted sequence of stable ordered phases peculiar to Fe-Co and the stabilization of B2 against disordered phases by magnetism. Our Fe-Co BOP is suitable for atomistic simulations with thousands and millions of atoms.