Effect of Sintering Temperature on the Magnetocaloric Effect of Ni-Mn-In/Tb-Dy-Fe Composites

In this study, the (Ni50Mn34.75In15.25)0.9/(Tb0.3Dy0.7Fe1.92)0.1 composites were prepared by spark plasma sintering method, and the influence of different sintering temperatures on the magnetocaloric effect of the composites was studied. For the composite sintered at 923 K, the adiabatic temperature change at a 1.5-T magnetic field is as high as - 2.8 K, and the effective refrigeration capacity at a 5-T magnetic field reaches up to 190 Jkg-1. This is attributed to the fact that internal stresses generated by the magnetostriction of the Tb0.3Dy0.7Fe1.92 particles assist in the magnetic field-driven inverse martensitic transformation and reduce the critical field for phase transition. As the sintering temperature increases to 1023 K, the thermoelastic martensitic transformation characteristic of the composite disappears, which is attributed to the generation of more Fe-rich and In-poor phases in the composite.