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

We investigated the effect of synthesis methods on the magnetic entropy change and magnetocaloric property. The amorphous ribbons were observed not only inverse but also typical phase transition contrary to the crystalline samples. Also, the magnetic entropy change of Zr including amorphous ribbon was nine times higher than that of crystalline samples. Therefore, controlling of production methods and selection of optimized composition are important to obtain enhanced magnetocaloric materials. [Display omitted] •The Co-based Heusler alloys with high Curie temperature were produced by various methods.•The Zr including amorphous ribbon was improved the magnetocaloric property.•The amorphous ribbons were indicated not only inverse but also typical phase transition.•The controlling of production methods and selection of optimized composition are important. 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 Co85.5Sn4.5Hf10 alloy.