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

Abstract

Novel Gd 56− x Dy x Al 24Co 20 ( x = 0, 14, 17) bulk metallic glasses (BMGs) were prepared by copper mold casting. They exhibit magnetic entropy changes (Δ S M ) comparable to that of Gd 53Al 24Co 20Zr 3 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 Gd 56Al 24Co 20, Gd 42Dy 14Al 24Co 20, and Gd 39Dy 17Al 24Co 20 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 Δ S M 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.