Multi-principal rare-earth Gd-Tb-Dy-Ho-Er alloys with high magnetocaloric performance near room temperature

Abstract

Magnetocaloric materials with enhanced magnetocaloric effect and high magnetic transition temperature are crucial for magnetic refrigeration, a novel cooling technology featuring high energy efficiency, low noise and superb environmental friendliness. In this study, a series of Gdx(TbDyHoEr)1-x (x=0.2–0.9) rare-earth alloys with a single-phase HCP (hexgonal-close-packed) structure, were developed utilizing a multi-principal element alloying strategy. It was found that the Gd0.8(TbDyHoEr)0.2 alloy exhibits a high magnetic transition temperature (i.e., ∼268 K), and concurrently enhanced magnetocaloric properties with a maximum magnetic entropy change value of 10.53 J kg−1 K−1 under a field change of 5 T and a refrigerant capacity value of 751.8 J kg−1. Notably, for these multi-principal element alloys, the maximum magnetic entropy change is essentially linearly correlated with the configuration entropy of mixing while the magnetic transition temperature scales with the de Gennes factor, which can be interpreted as a manifestation of ideal solid solutions. This work provides important implications for designing high-performance magnetocaloric materials for magnetic refrigeration.