Magnetocaloric Properties of Low-Cost Fe and Sn Substituted MnNiSi-Based Alloys Exhibiting a Magnetostructural Transition Near Room Temperature

The magnetocaloric properties of rare-earth free Mn0.45Fe0.55NiSi1-ySny (y = 0.12, 0.14, 0.16, and 0.18) alloys were studied. The raw material cost is significantly lower than the counterpart alloys containing Ge or Ga. Sn substitution reduced the Curie temperature (T-c) from 343 K (for y = 0.12) to 248 K (for y = 0.18), offering a wide range of working temperatures near room temperature. The alloys exhibited a training effect. The first-order transition weakened as the Sn content increased from 0.12 to 0.18. Interestingly, magnetostructural transformation was observed near room temperature for y = 0.14, with a maximum entropy change (Delta S-max) of 8.64 Jkg(-1)K(-1) for a field change of 5 T. Hence, Mn0.45Fe0.55NiSi1-ySny alloys are promising candidates for low cost, near room temperature, magnetocaloric applications.