Magnetism Matters: Modelling Atomic Arrangements in Multicomponent Alloys
Date:
Contributed talk at the 43rd CCP5 Annual General Meeting.
Abstract
Understanding the nature of atomic short-range order (ASRO) in multicomponent alloys, such as medium- and high-entropy alloys, is crucial for predictive modelling of their physical properties. Frequently, studies examining the phase stability of these complex solid solutions use supercell calculations with energies evaluated via density functional theory, either to study atomic arrangements directly or to train interatomic potentials for subsequent atomistic modelling. Often, these DFT calculations are spin-polarised and allow magnetic moments to form and magnetic order to emerge between elements such as Fe, Co, Ni, and Mn. However, experimentally, it is common to anneal these materials at temperatures well above their Curie temperature, where the magnetic state is, in fact, paramagnetic. Here, we present results from an all-electron, first-principles, Landau-type linear response theory [1,2], and show that treatment of magnetism can have significant impact on the nature of predicted atomic arrangements and the temperature at which ordered structures emerge in these materials. We study the prototypical family of high-entropy alloys, CrMnFeCoNi and its derivatives, and show how competition between various ordered structures has its origins in treatment of the materials’ magnetic state [3]. Our computationally efficient approach for modelling atomic arrangements in multicomponent alloys can be used to generate supercell configurations with physically motivated ASRO for use in subsequent analyses of materials properties, and for use in training datasets for interatomic potentials.
References
[1] C. D. Woodgate, J. B. Staunton, Phys. Rev. B, 105, 115124 (2022).
[2] C. D. Woodgate, J. B. Staunton, Phys. Rev. Mater. 7, 013801 (2023).
[3] C. D. Woodgate, D. Hedlund, L. H. Lewis, J. B. Staunton, Phys. Rev. Mater. 7, 053801 (2023).