Magnetocaloric effect in high Ni content Ni52Mn48-xInx alloys under low field change

Ni-rich Heusler alloys Ni52Mn48-xInx (x=15.5, 16 and 16.5) were prepared by the arc melting method. X-ray diffraction analysis revealed that the martensite has orthorhombic structure (S.G. Pmm2) at room temperature. The only alloy with x=15.5 has structural transmission from martensite to austenite without any magnetic transmission. The temperature dependence and the field dependence of the magnetization measurement indicated that the magnetization increased with the decreasing of the concerntration of Mn. The lesser the Mn atoms located in the In atom sites, the weaker the total AFM interaction in the system. Giant entropy changes ΔSM(T, H) were found in Ni52Mn48-xInx alloys with the maximum ΔSM value of 22.3 J kg K for the sample with x=16.5 at 270 K under the magnetic field change of 1.5 T. - Highlights: → Hight Ni content Heusler alloy Ni52Mn48-xInx (x=15.5, 16.0 and 16). → Marstensitic structural-magnetic transformation at room temperature. → Lesser Mn at In atomic site, higher magnetization and difference between marstensite and austenite. → Large magnetocaloric effect under low magnetic field change of 1.5 T.