Increased magnetocaloric response of FeMnNiGeSi high-entropy alloys

Abstract

The search for high-entropy alloys (HEAs), a new class of materials, with high magnetocaloric perfor- mance 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 ap- proach, FeMnNiGeSi HEAs with varying Ge/Si ratio are found in the large HEA space to exhibit magneto- structural 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 con- ventional systems, closing the gap between magnetocaloric HEAs versus conventional magnetocaloric ma- terials for the first time. This opens a new path for the search of functional materials with the optimal mechanical properties of HEAs.