Effect of Sb-doping on martensitic transformation and magnetocaloric effect in Mn-rich Mn₅₀Ni₄₀Sn_10-xSb_x (x=1, 2, 3, and 4) alloys

We investigate the influence of Sb-doping on the martensitic transformation and magnetocaloric effect in Mn₅₀Ni₄₀Sn_10-xSb_x (x=1, 2, 3, and 4) alloys. All the prepared samples exhibit a B2-type structure with the space group Fm3m at room temperature. The substitution of Sb increases the valence electron concentration and decreases the unit cell volume. As a result, the magnetostructural transformation shifts rapidly towards higher temperatures as x increases. The changes in magnetic entropy under different magnetic field variations are explored around this transformation. The isothermal magnetization curves exhibit typical metamagnetic behavior, indicating that the magnetostructural transformation can be induced by a magnetic field. The tunable martensitic transformation and magnetic entropy changes suggest that Mn₅₀Ni₄₀Sn_10-xSb_x alloys are attractive candidates for applications in solid-state refrigeration.