130. MAGNETO CALORIC PROPERTIES OF NANO-GRAINED NIMNSN HEUSLER ALLOY
Name: Dongwon Chun
Grad Year: 2016
Magnetocaloric material in which repeated magnetization and demagnetization by magnetic field causes the material to gradually cool, thus accomplishing refrigeration by purely magnetic means. NiMnSn Heusler based magnetocaloric alloy have received much attention because of both its large entropy change around the room temperature and low cost material. However, its magnetocaloric temperature region having large entropy change is narrow (4K at 3T) so that there is a limitation for the cooling system application. In this research, magnetocaloric properties of nano-grained NiMnSn alloy were investigated to evaluate the potential of this material as magnetic refrigerants. As shown in Fig. 1, nano sized NiMnSn particles were fabricated by the spark-erosion and followed by hot pressing to make nano grained NiMnSn pellets. The magnetic entropy change (ΔS), magnetocaloric temperature span and refrigerant capacity (RC) are evaluated indirectly from isotherm magnetization (M-H) curves with applying magnetic field up to 3T around room temperature. Results reveal nano-grained NiMnSn improves magnetocaloric temperature span and RC rather than NiMnSn bulk which is preferable for the refrigerator application.