Structural and Magnetic Properties of Fe-Al alloys: an Ab initio Studies

TL;DR

This study uses ab initio methods to analyze how the structural and magnetic properties of Fe-Al alloys change with aluminum content and structural order, providing insights into their lattice, elastic, and magnetic behaviors.

Contribution

It presents a comprehensive ab initio investigation of Fe-Al alloys' structural, elastic, and magnetic properties across different compositions and structures, including Curie temperature predictions.

Findings

Lattice constants increase with Al content.

Shear modulus decreases as Al content rises.

Curie temperatures vary across compositions.

Abstract

In the framework of density functional theory, the structural and magnetic properties of Fe$_{100-x}$Al$_x$ alloys (${5 \leq x \leq 25}$~at.\%) with the different structural order are investigated. Using the Korringa-Kohn-Rostoker Green's function method with a coherent potential approximation, the equilibrium lattice parameters, ground-state energy, and shear moduli for D0$_3$, B2, and A2 structures are calculated. For all structures, the optimized lattice constant increases while the shear modulus demonstrates a decreasing behavior with increasing Al content. The tetragonal magnetostriction constants are estimated by the torque method. The A2 and B2 structures provide a positive contribution to the tetragonal magnetostriction. With the help of Monte Carlo simulations of the Heisenberg model, the Curie temperatures are obtained in a wide concentration range.