Giant magnetocaloric effect in melt-spun Ni-Mn-Ga ribbons with magneto-multistructural transformation

Magnetic refrigeration based on the magnetocaloric effect (MCE) may provide an energy-efficient and environment-friendly alternative to the conventional gas compression/expansion cooling technology. For potential applications, low-cost and high-performance magnetic refrigerants are in great need. Here, we demonstrate that giant MCE can be achieved in annealed Ni52Mn26Ga22 ribbons with magneto-multistructural transformation. It yields a maximum magnetic entropy change of −30.0 J kg−1 K−1 at the magnetic field change of 5 T, being almost three times as that of initial melt-spun ribbons and comparable to or even superior to that of polycrystalline bulk alloys.