High-throughput design of all-d-metal Heusler alloys for magnetocaloric applications

TL;DR

This study employs high-throughput density functional theory to identify and analyze all-d-metal Heusler alloys with promising mechanical and magnetocaloric properties, advancing materials for energy-efficient cooling and shape memory devices.

Contribution

It introduces a comprehensive computational screening of all-d-metal Heusler alloys, revealing their preferred structures, mechanical robustness, and potential for magnetocaloric applications, which was previously unexplored.

Findings

Identified 686 (meta)stable all-d-metal Heusler compounds.

Discovered the inverse Heusler structure is favored with small electronegativity differences.

Found 49 compounds with potential for magnetocaloric and shape memory applications.

Abstract

Due to their versatile composition and customizable properties, A$_2$BC Heusler alloys have found applications in magnetic refrigeration, magnetic shape memory effects, permanent magnets, and spintronic devices. The discovery of all-$d$-metal Heusler alloys with improved mechanical properties compared to those containing main group elements, presents an opportunity to engineer Heuslers alloys for energy-related applications. Using high-throughput density functional theory calculations, we screened magnetic all-$d$-metal Heusler compounds and identified 686 (meta)stable compounds. Our detailed analysis revealed that the inverse Heusler structure is preferred when the electronegativity difference between the A and B/C atoms is small, contrary to conventional Heusler alloys. Additionally, our calculations of Pugh ratios and Cauchy pressures demonstrated that ductile and metallic bonding are widespread in all-$d$-metal Heuslers, supporting their enhanced mechanical behaviour. We identified 49 compounds with a double-well energy surface based on Bain path calculations and magnetic ground states, indicating their potential as candidates for magnetocaloric and shape memory applications. Furthermore, by calculating the free energies, we propose that 11 compounds exhibit structural phase transitions, and propose isostructural substitution to enhance the magnetocaloric effect.