Increased magnetocaloric response of FeMnNiGeSi high-entropy alloys

The search for high-entropy alloys (HEAs), a new class of materials, with high magnetocaloric performance can address the open question about their potential in functional applications. HEAs exist in a vast compositional space but magnetocaloric HEAs typically exhibit modest magnetocaloric response as they undergo second-order magnetic phase transitions. In this work, through a property-directed search approach, FeMnNiGeSi HEAs with varying Ge/Si ratio are found in the large HEA space to exhibit magnetostructural first-order phase transition. Isothermal entropy change as large as 13 J kg -1 K -1 (for 2.5T) is achieved, which is the largest reported to date for magnetocaloric HEAs. When compared to conventional high-performance magnetocaloric materials, our work is observed to be comparable to many of the conventional systems, closing the gap between magnetocaloric HEAs versus conventional magnetocaloric materials for the first time. This opens a new path for the search of functional materials with the optimal mechanical properties of HEAs. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Automated summary

The search for high-entropy alloys (HEAs) with high magnetocaloric performance has led to the discovery of FeMnNiGeSi HEAs with magnetostructural first-order phase transition, achieving the largest reported isothermal entropy change for magnetocaloric HEAs. The study demonstrates comparable performance to conventional high-performance magnetocaloric materials, bridging the gap between HEAs and conventional systems for the first time, opening up a new path for functional materials with optimal mechanical properties.