Wide temperature window of magnetostructural transition achieved in Mn0.4Fe0.6NiSi1−xGax by a two-step isostructural alloying process

Abstract

A new approach has been proposed in this work, which provides an effective way for tuning the structural transition in MM’X systems with relatively high transition temperature. With this method, a temperature window as wide as 275 K for the magnetostructural transition has been achieved in the MnNiSi alloy system. The maximum magnetic entropy change of the system is as high as 13.3 J/kgK, which, together with the large temperature window, enables the Mn0.4Fe0.6NiSi1−xGax system to be a promising candidate for magnetic refrigerant applications.

Influence of magnetic field, chemical pressure and hydrostatic pressure on the structural and magnetocaloric properties of the Mn–Ni–Ge system

“…However, the preparation of powder for XRD measurement induces stresses in the material influencing the transition temperature of the compound. Similar observations have also been reported by Chen et al [45] for the Mn-Fe-Ni-Si system with Ga substitution and Scheerbaum et al [46] for Ni-Co-Al Heusler alloy. The other samples transform below room temperature and for this reason only show reflections of the hexagonal high temperature phase in figure 5(a).…”

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

“…The RCP values for Mn 0.45 Fe 0.55 NiSi 1−y Sn y obtained by product of FWHM and the S max value were 116, 79, 133, and 156 Jkg −1 for y = 0.12, 0.14, 0.16, and 0.18, respectively. The RCP values are comparable with other MnNiSi-based alloys, e.g., Mn 0.4 Fe 0.6 NiSi 0.96 Ga 0.04 (136 Jkg −1 ) [24] and (MnNiSi) 0.62 (CoNiGe) 0.38 (169 Jkg −1 ) [43].…”

“…Hence, two alloying elements are needed to obtain magnetostructural coupling near room temperature for MnNiSi-based alloys. MST near room temperature occurred in MnNiSi-based systems such as MnNiSi-FeNiGe [17], MnNiSi-FeCoGe [18], MnNiSi-MnFeGe [19], MnNiSi-Fe 2 Ge [20], [21], MnNiSi-CoNiGe [22], (Mn, Fe) Ni (Si, Al) [23], (Mn, Fe) Ni (Si, Ga) [24], and (MnNiSi) 1−x (Co 2 Ge) x [25]. Mn has been substituted by Fe; Co and Si by Al, Ga, and Ge.…”