Magnetocaloric Properties of Melt-Spun Fe–Ni–Mn–Ga Ribbons

The effects of Ni substitution for Fe on phase constitutions, Curie temperature, and magnetocaloric properties of melt-spun Fe- Ni Mn Ga ( 0, 1, 3, 5 and 7) ribbons have been investigated. X-ray diffraction results show that the main phase in the Fe- Ni Mn Ga (-) alloy changed with the increase of Ni content from FCC structure for into B2 structure for-. Besides, the magnetic phase exhibits phase transition of ferromagnetic into paramagnetic state with increasing temperature for the samples with B2-type structure. The Curie temperature of these ribbons varies in the temperature range of- K. The peak values of the maximal magnetic entropy change,-, are about- Jkg/K for Ni-substituted ribbons at a maximum applied field of 30 kOe. On the other hand, the relatively broader temperature range at the half maximum of peak ( K), low-cost and nontoxic elements make Fe–Ni–Mn–Ga-based ribbons the promising candidates for magnetic refrigeration applications close to room temperature. Index Terms—Heusler alloy, magnetocaloric properties, melt-spun ribbon. I