Large magnetic entropy change in Ni–Mn–In–Sb alloys via directional solidification and calculated by first-principles calculations.

In this work, the magnetocaloric effect in Ni50Mn36In5Sb9 alloy was increased by more than 50% through directional solidification, and the magnetic entropy change increased to 36.2 J kg−1 K−1 under the field of 5 T. The calculated results of differential scanning calorimetry curves confirmed the enhanced entropy change, which also increased from 29.7 to 40.7 J kg−1 K−1. Moreover, first-principles calculations show that the surface formation energy along the L21 (220) plane is the lowest at room temperature, and it is easy to form and undergo martensitic transformation from the (220) crystal plane. Directional solidification causes the alloy to grow basically toward the (220) crystal plane, improve atomic ordering, reduce grain boundaries, and increase grain size. Thereby, the magnetic entropy change is enhanced. [ABSTRACT FROM AUTHOR]