Distinct spin glass behavior and excellent magnetocaloric effect in Er20Dy20Co20Al20RE20 (RE = Gd, Tb and Tm) high-entropy bulk metallic glasses

The Er20Dy20Co20Al20RE20 (RE = Gd, Tb and Tm) high-entropy bulk metallic glasses (HE BMGs) with tunable magnetocaloric properties were prepared successfully. As a result, a spin glass behavior was observed below 50 K in this HE BMG system. In addition, we found that the Curie temperature (TC) can be easily tuned from 13 to 43 K by alloying different rare earth (RE) elements, following a good de Gennes factor dependence. The peak of magnetic entropy change |ΔSMmax| for Gd-, Tb- and Tm-containing glassy alloy under a magnetic field of 5 T is 9.1, 8.6 and 11.9 J kg−1K−1, respectively, which leads to obtain the maximum refrigerant capacity (RC) of 619, 525, and 405 J kg−1 for the Er20Dy20Co20Al20RE20 (RE = Gd, Tb and Tm) HE BMGs, respectively. The glass-forming ability (GFA), TC, ΔSM and RC can be widely tuned by alloying different RE elements. These results suggest that these HE BMGs are promising magnetic refrigerants at low temperature in the future.