Computational screening of magnetocaloric alloys

Abstract

An exciting development over the past few decades has been the use of high-throughput computational screening as a means of identifying promising candidate materials for a variety of structural or functional properties. Experimentally, it is often found that the highest-performing materials contain substantial atomic site disorder. These are frequently overlooked in high-throughput computational searches however, due to difficulties in dealing with materials that do not possess simple, well-defined crystallographic unit cells. Here we demonstrate that the screening of magnetocaloric materials with the help of the density functional theory-based magnetic deformation proxy can be extended to systems with atomic site disorder. This is accomplished by thermodynamic averaging of the magnetic deformation for ordered supercells across a solid solution. We show that the highly non-monotonic magnetocaloric properties of the disordered solid solutions Mn(Co1−xFex)Ge and (Mn1−xNix)CoGe are successfully captured using this method. arXiv:1911.12218v2 [cond-mat.mtrl-sci]

Structural changes upon magnetic ordering in magnetocaloric AlFe2B2

“…4 A survey of magnetocalorics based on density functional theory calculations has established a broad correlation between magnetostructural coupling (approximated using magnetic deformation calculations) and MCE in materials with both first-order and continuous transitions. 11,12,19,20 This work made the prediction that AlFe 2 B 2 , among some other materials with strong magnetocaloric effects observed at continuous magnetic transitions, would display strong magnetostructural coupling when investigated experimentally. AlFe 2 B 2 was first isolated and its crystal structure solved by Jeitschko in 1969.…”

Evolution of noncollinear magnetism in magnetocaloric MnPtGa

“…It has been suggested that promising candidate materials for magnetic refrigeration via the magnetocaloric effect can be evaluated through a computational proxy known as magnetic deformation, or Σ M [9,10]. This proxy is a predictor of the strength of magnetostructural coupling in a given material calculated using density functional theory (DFT).…”

Designing of magnetic MAB phases for energy applications

“…We suspect such compounds can exhibit signicant DS M upon second order phase transition at the corresponding Curie temperature, which will be saved for detailed investigation in the future. Additionally, isostructural doping can be applied to improve the magnetocaloric performance 80 or to ne tune the magnetostructural or metamagnetic transitions, 81 which enables further design of magnetocaloric materials with optimal performance.…”