Magnetocaloric and Electrical Properties in Annealed Si-Doped Ni–Mn–In Heusler Alloy Ribbons

The magnetocaloric and electrical properties in annealed Si-doped Ni₄₈Mn₃₉In_13-xSi_x Heusler alloy ribbons with x=0-3 have been investigated. These ribbons crystallize in a partially ordered B2 phase structure. It was observed that both the martensitic structural transition T_M and the Curie temperature T_C of austenitic phase decrease with increasing Si contents. The small amount of Si in the In position modifies the peak value of positive magnetic entropy change ΔS_M for a magnetic field change H=50 kOe, which vary from 20.2 J·kg^-1·K^-1 for x=0 to 23.1 J·kg^-1·K^-1 for x=1 , and then decrease to 10.1 J·kg^-1·K^-1 for x=3. Meanwhile, the magnetoresistance associated with the martensitic transformation was found to be -45% for x=2 at T=192 K for a magnetic field change of 50 kOe.