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 Mn
_0.45
Fe
_0.55
NiSi
_1-y
Sn
_y
(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 (ΔS
_max
) of 8.64 Jkg
^-1
K
^-1
for a field change of 5 T. Hence, Mn
_0.45
Fe
_0.55
NiSi
_1-y
Sn
_y
alloys are promising candidates for low cost, near room temperature, magnetocaloric applications.