Phase separation and its effect on the magnetic entropy change profile in an amorphous Gd48Co50Nb2 alloy

In the present work, we studied the microstructure, thermal and magnetic properties of a Gd48Co50Nb2 amorphous ribbon for the purpose of revealing the mechanism of the table-like magnetic entropy change (−ΔSm) profile of the ribbon. It was found that the amorphous ribbon was fully amorphous with only short-range orders. The two-step magnetic phase transitions indicate that there are two amorphous phases in the Gd48Co50Nb2 amorphous ribbon. The table-like −ΔSm profile of the Gd48Co50Nb2 amorphous ribbon is supposed to be due to the superposition of two −ΔSm peaks corresponding to two separated amorphous phases with different magnetic properties. The amorphous ribbon is expected to be a good candidate for magnetic refrigerant because of its high maximum −ΔSm and high effective refrigeration capacity of the specific table-like −ΔSm profile.