Influence of magnetic entropy on stability and thermodynamic properties of Laves phase Fe2Mo from first principles

TL;DR

This study uses first-principles calculations to analyze how magnetic entropy influences the stability and thermodynamic properties of Fe2Mo Laves phase, emphasizing the importance of magnetic contributions for accurate predictions.

Contribution

A new method for determining thermal expansion paths is proposed, integrating magnetic entropy into thermodynamic stability analysis of Fe2Mo.

Findings

Magnetic entropy significantly affects the stability predictions of Fe2Mo.

The proposed method simplifies thermal expansion calculations to a one-dimensional problem.

Results agree with experimental data, validating the approach.

Abstract

The thermodynamic and physical properties of the Laves phase Fe2Mo have been investigated using the finite-temperature quantum mechanical calculations within the frame of the density functional theory (DFT). All relevant free energy contributions including electronic, vibrational and magnetic excitations are considered. The quasi-harmonic Debye - Gruneisen theory is used. In this work, a new method of searching a thermal expansion path of compounds is proposed. It allows to reduce the problem to a one-dimensional case and minimize the free energy in one variable, in volume. The heat capacity, thermal expansion, elastic constants and bulk modulus are modelled. The calculated results analyzed and are in an agreement with the available experimental data. It is shown that magnetic entropy must be considered on equal footing with vibrational and electronic energies to reliably predict stability of Fe2Mo.