Theoretical modelling of magnetic and magnetocaloric properties in rare-earth high-entropy compounds: Insights from Gd0.2Tb0.2Dy0.2Ho0.2Er0.2Al2

In this study, we investigate the magnetic and magnetocaloric properties of the high-entropy compound (HECs) Gd₀.₂Tb₀.₂Dy₀.₂Ho₀.₂Er₀.₂Al₂, focusing on the complex interactions between rare-earth sublattices. Our multi-sublattice Hamiltonian model considers crystalline electric field interactions, Zeeman effect for the five rare-earth sublattices and the exchange interaction among combinations of rare-earth ions. Intra- and inter-sublattice exchange interactions were adjusted based on parent RAl₂ compounds and pseudo-binary R₁₋ₓR’ₓAl₂ (with R and R’ corresponding to rare-earth elements) materials to match the Curie temperature and magnetocaloric behavior. Our theoretical model shows good agreement with experimental data. The easy magnetization direction was determined to be along the 〈111〉 axis. We also compared the magnetocaloric performance of the HECs with simulated composites. This study suggests that HECs based on RAl₂ compounds have potential for optimizing magnetocaloric behavior, particularly in low-temperature cooling applications.