Influence of Co and Ni addition on the magnetocaloric effect in Fe88-2xCoxNixZr7B4Cu1 soft magnetic amorphous alloys

We have studied the magnetocaloric effect in a series of Fe88-2xCoxNixZr7B4Cu1 alloys. The partial substitution of Fe by Co and Ni leads to a monotonic increase in the Curie temperature (T-C) of the alloys from 287 K for x=0 to 626 K for x=11. The maximum magnetic entropy change (Delta S-pk(M)) at an applied field of 1.5 T, shows a value of 1.98 J K-1 kg(-1) for x=8.25. The refrigerant capacity (RC) has maximum values near 166 J kg(-1) (for x=0 and 2.75). These values place the present series of alloys among the best magnetic refrigerant materials, with an RC similar to 40% larger than Gd5Si2Ge1.9Fe0.1 and similar to 15% larger than Fe-based amorphous alloys. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3427439]