Coupled Magnetic and Structural Transitions in Fe-Doped MnNiSi Compounds

In this paper, we obtained a ferromagnetic (FM) Mn_0.36Fe_0.6Ni_0.98Si compound in which magnetic and structural transitions are coupled together. By combining Fe doping and Mn depletion, the magnetostructural coupling was realized, with a magnetostructural transition happening at 337 K from paramagnetic hexagonal phase to FM orthorhombic phase. The magnetocaloric effect was measured across the transition, showing a wide temperature span and a zero magnetic hysteresis loss. The maximum values of magnetic entropy change and refrigeration capacity near reverse martensitic transition (~367 K) are -2.52 J kg^-1 K^-1 and 108 J kg^-1, respectively, under a field change of ΔH = 0 ~ 50 kOe.