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

The magnetocaloric and electrical properties in annealed Si-doped Ni48Mn39In13-xSix 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 Delta S-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.