Gd–Dy–Al–Co bulk metallic glasses with large magnetic entropy change and refrigeration capacity

Novel Gd56−xDyxAl24Co20 (x = 0, 14, 17) bulk metallic glasses (BMGs) were prepared by copper mold casting. They exhibit magnetic entropy changes (ΔSM) comparable to that of Gd53Al24Co20Zr3 BMG and crystalline Gd. Moreover, these glassy alloys have broad entropy change peaks, resulting in the refrigeration capacities of 751.4 J kg−1, 702.8 J kg−1, and 682.3 J kg−1 for Gd56Al24Co20, Gd42Dy14Al24Co20, and Gd39Dy17Al24Co20 at 5 Tesla. The large magnetocaloric effect makes these BMGs attractive candidates as magnetic refrigerant in temperature range of 50–140 K. It is also found that the Curie temperature of this kind of metallic glass linearly declines with the increase of Dy. The ΔSM of metallic glasses reaches maximum at certain content of Dy. These findings are expected to provide a meaningful guidance for the composition design of rare earth based glassy alloys for refrigeration application.