Magnetostructural transition and magnetocaloric effect in thermally annealed Mn0.5Fe0.5NiSi0.945Al0.055 melt-spun ribbons

Abstract Were fabricated melt-spun ribbons of the quinary alloy Mn0.5Fe0.5NiSi0.945Al0.055. After an annealing time of 4 hours at temperatures between 1073 K and 1223 K, samples underwent a martensitic-like magnetostructural transformation around room temperature from a paramagnetic Ni2In-type hexagonal structure to a ferromagnetic TiNiSi-type one. The phase transformation practically remained unchanged with the annealing temperature, whereas the first cooling process induced a massive cracking in the samples. In comparison to the reported in literature for bulk alloys, the melt-spun ribbons showed a lower maximum magnetic field-induced entropy change but a well-broader working temperature range. A relatively low magnetic hysteresis loss was obtained across the martensitic transformation.