Effect of synthesis methods on magnetocaloric properties of Co-based Heusler-type alloys

Abstract

We evaluated the effect of fabrication methods such as arc melting, suction casting, spark plasma sintering and melt spinning on the magnetocaloric properties, i.e., magnetization, magnetic entropy change, and relative cooling power, of Co-based Heusler-type alloys having a high Curie temperature (> 700 K). We also investigated entropy changes caused by phase transformation. Magnetic entropy change in the amorphous ribbon synthesized by melt spinning is much larger than that in the crystal sample within the high-temperature range. Moreover, unlike crystalline samples, both direct and inverse magnetocaloric effects were observed in the amorphous ribbons. Magnetocaloric properties of amorphous ribbon samples were superior to those of the other samples at temperatures above 745 K. The amorphous ribbon of the Co85.5Sn4.5Zr10 alloy showed about 1.5 times stronger MCE that of the amorphous Co(85.5)Sn(4.5)Zf(10) alloy.