Near room-temperature magnetocaloric effect in amorphous FeSc alloys: the effect of minor Co additions

The fabrication and magnetocaloric effect studies of Fe90-xCoxSc10 (x = 1, 3, 5 and 7) amorphous alloys are reported herein. The addition of Co content can not only tune the Curie temperature of these alloys to room temperature, but also simultaneously increase the maximum value of the magnetic entropy change (−ΔSMpk). The −ΔSMpk is 1.40 J/kg K at ΔH = 1.5 T (ΔH: magnetic field change) with x = 7. The maximum refrigerant capacity (RC) is 191.9 J/kg at ΔH = 1.5 T with x = 3, which is higher than that of most of Fe-based amorphous alloys so far discovered. Increasing the ΔH to 2 T, the RC values of these alloys can reach as high as 265.2 J/kg, which is comparable to those detected in crystalline Gd and Gd5Si2Ge2. Enhanced RC values observed in these alloys promise them to be good candidates for near room-temperature magnetic refrigerants.