Fig 1. Typical SEM images of the fracture cross section [(a) and (c)] and free surface [(b) and (d)] for the melt-spun [(a) and (b)] and annealed [(c) and (d)] MnNi0.82Fe0.18Ge ribbons.

Fig. 2. XRD patterns recorded at RT for melt-spun and annealed MnNi1-xFexGe (x = 0.15 (a), 0.18 (b)) ribbons. Hklh and hklo denote the Miller indices of the hex. Ni2In-type and orth. TiNiSi-type structure, respectively.

Fig. 3. DSC curves of the melt-spun [(a) and (c)] and annealed [(b) and (d)] ribbons for the x = 0.15 [(a) and (b)] and x = 0.18 [(c) and (d)] ribbons with the heating and cooling rates of 10 K min-1. Arrows indicate the temperature evolution direction.

Fig. 4. M(T) curves measured at μ0H = 0.1 T (square symbols), 0.5 T (triangle symbols), and 0.9 T (circle symbols) applied fields on cooling and heating for melt-spun MnNi1-xFexGe (x = 0.15 (a), 0.18 (b)) ribbons. The inset indicates the M(T) curves under 0.9 T measured continuously for three cycles.

Fig. 5. M(T) curves measured under the field of μ0H = 0.9 T on heating before (diamond symbols) and after (circle symbols) annealing for x = 0.15 (a) and x = 0.18 (b) ribbons. The insets present M(T) curves upon heating and cooling processes around Tt for annealed ribbons.

Fig. 6. Isothermal M(H) curves measured near Tt with field-up and field-down processes for annealed x = 0.15 [(a) and (c)] and x = 0.18 [(b) and (d)] ribbons upon heating [(a) and (b)] and cooling [(c) and (d)]. The insets indicate the magnetic phase graphs derived from the respective M(H) curves in these figures. The arrows denote the evolution of magnetic phases.

Fig. 7. ΔS(T) curves under the field change of ΔH = 0—3 T for x = 0.15 (circle symbols) and x = 0.18 (triangle symbols) ribbons in the heating (open symbols) and cooling (solid symbols) runs. The inset denotes the temperature dependence of magnetic hysteresis for x = 0.15 (open diamond symbols) and x = 0.18 (solid triangle symbols) ribbons upon cooling process.

Fig. 8. M(H) loops measured at several temperatures near Tt upon cooling for x = 0.15 (a) and x = 0.18 (b) ribbons. The insets on the bottom-right corner of these figures indicate the enlarged view of M(H) loops in the first quadrant. The inset of lower-left corner of (a) denote the enlarged view of M(H) loops in the third quadrant.

Fig. 9. Typical SEM images of the fracture cross section (a) and free surface (b) for annealed Mn0.96Fe0.04NiGe ribbons.

Fig. 10. XRD spectra recorded at RT for annealed Mn0.96Fe0.04NiGe ribbons. Hklh and hklo denote the Miller indices of the hex. Ni2In-type and orth. TiNiSi-type structure, respectively.

Fig. 11. Heating and cooling DSC curves of annealed Mn0.96Fe0.04NiGe ribbons with the rates of 10 K min-1. Arrows indicate the evolution of temperature.

Fig. 12. M(T) curves measured at applied fields of μ0H = 0.1 T (a), 0.3 T (b), 1.0 T (c) and 2.5 T (d) on heating for annealed Mn0.96Fe0.04NiGe ribbons. The insets of (a) and (d) indicate the M(T) curves measured upon heating and cooling.

Fig. 13. (a) M(H) curves measured by adopting loop method and (b) -ΔS(T) curves under the field change of ΔH = 0—1 (square symbols), 2 (circle symbols), 3 (upper triangle symbols), 4 (lower triangle symbols), and 5 T(left triangle symbols) for Mn0.96Fe0.04NiGe ribbons. The inset of (a) denote the temperature dependence of magnetic hysteresis.