The magnetocaloric effect and refrigeration capacity ͑RC͒ of Gd 55 Co 20 Al 25 and Gd 55 Ni 25 Al 20 bulk metallic glasses ͑BMGs͒ have been investigated. Large magnetic entropy changes ⌬S M of 11.2 and 10.8 J kg −1 K −1 and large RC values of 846 and 920 J kg −1 are obtained for Gd 55 Co 20 Al 25 and Gd 55 Ni 25 Al 20 , respectively, at a field change of 7 T. The RC value ͑640 J kg −1 at 5 T or 920 J kg −1 at 7 T͒ of Gd 55 Ni 25 Al 20 BMG is larger than that reported for all magnetocaloric materials, including crystalline and amorphous materials measured under the same conditions. The large RC value is due to the broad ⌬S M peak ͑more than 100 K͒, which is caused by the disordered structure of an amorphous material. The large ⌬S M and RC values make these Gd-based ternary BMGs attractive candidates for magnetic refrigeration applications.

Magnetic and magnetocaloric effects of (Mn1−xFex)5Ge3 compounds are studied systematically. The maximum of magnetic entropy changes of 8.01 J/kg K under an external field change of 5 T is obtained for (Mn0.9Fe0.1)5Ge3, which is the largest value in Mn5Ge3-based solid solutions. Moreover, the Fe substitution increases the refrigeration capacity (RC) value greatly. The largest RC value of 237 J/kg in (Mn0.8Fe0.2)5Ge3 even compares favorably to that of many well-known magnetic refrigeration materials. Thus the Fe-containing (Mn1−xFex)5Ge3 compounds are much-improved magnetic refrigerants for the application of room-temperature magnetic refrigeration. The increase of the RC value is probably resulted from the formation of magnetic nanostructure.