A Finemet-type alloy as a low-cost candidate for high-temperature magnetic refrigeration

Abstract

The refrigerant capacity (RC) of Fe68.5 Mo5 Si13.5 B9 Cu1 Nb3 alloy is studied. For the amorphous sample, RC=63 J kg-1 for an optimal reversible cycle with cold and hot ends at 328 K and 520 K, respectively, for a maximum applied field H=15 kOe. Nanocrystallization diminishes both the peak entropy change and RC of the material. Although the measured RC is smaller than for Gd5 Ge1.9 Si2 Fe0.1 (240 J kg-1 for H=50 kOe), the Mo-Finemet alloy is more than 20 times cheaper, the applied field employed is smaller, and the temperature span of the optimal cycle is increased. This makes this alloy a promising material for high-temperature refrigeration. © 2006 American Institute of Physics.