We have studied magnetocaloric and elastocaloric properties of a Ni-Mn-Sn(Cu) metamagnetic shape-memory alloy undergoing a magneto-structural transition (martensitic type) close to room temperature. Changes of entropy have been induced by isothermally applying both mechanical (uniaxial stress) and magnetic fields. These entropy changes have been, respectively, estimated from dilatometric measurements giving the length of the sample as a function of temperature at selected applied forces and magnetic fields and from magnetization measurements as a function of temperature at selected applied magnetic fields. Our results indicate that the elastocaloric effect is conventional and occurs in two steps which reflect the interplay between the martensitic and the incipient magnetic transitions. By contrast, the magnetocaloric effect is inverse and occurs in a single step that encompasses the effect arising from both transitions.

Heusler alloy ${\mathrm{Mn}}_{50}{\mathrm{Ni}}_{40}{\mathrm{In}}_{10}$ was produced as preferentially textured ribbon flakes by melt spinning, finding the existence of martensitic-austenic transformation with both phases exhibiting ferromagnetic ordering. A microcrystalline three-layered microstructure of ordered columnar grains grown perpendicularly to ribbon plane was formed between two thin layers of smaller grains. The characteristic temperatures of the martensitic transformation were $M_S=213\mathrm{K}$ , $M_f=173\mathrm{K}$ , $A_S=222\mathrm{K}$ , and $A_f=243\mathrm{K}$ . Austenite phase shows a cubic $L{2}_1$ structure ($a=0.6013\left(3\right)\mathrm{nm}$ at $298\mathrm{K}$ and a Curie point of $311\mathrm{K}$ ), transforming into a modulated fourteen-layer modulation monoclinic martensite.

Magnetic refrigeration based on the magnetocaloric effect (MCE) may provide an energy-efficient and environment-friendly alternative to the conventional gas compression/expansion cooling technology. For potential applications, low-cost and high-performance magnetic refrigerants are in great need. Here, we demonstrate that giant MCE can be achieved in annealed Ni₅₂Mn₂₆Ga₂₂ ribbons with magneto-multistructural transformation. It yields a maximum magnetic entropy change of −30.0 J kg⁻¹ K⁻¹ at the magnetic field change of 5 T, being almost three times as that of initial melt-spun ribbons and comparable to or even superior to that of polycrystalline bulk alloys.

We determined the magnetic entropy change and refrigerant capacity of melt spun ${\mathrm{Ni}}_{50.3}{\mathrm{Mn}}_{35.5}{\mathrm{Sn}}_{14.4}$ ribbons around both the structural and the magnetic transitions for a field of $20\mathrm{kOe}$ . The maximum entropy changes at the structural and magnetic transitions were of 4.1 and $-1.1\mathrm{J}{\mathrm{kg}}^{-1}{\mathrm{K}}^{-1}$ . Ribbons studied show a larger refrigerant capacity around the magnetic transition $\left(46\mathrm{J}{\mathrm{kg}}^{-1}\right)$ than around the structural transition $\left(26\mathrm{J}{\mathrm{kg}}^{-1}\right)$ , suggesting that the temperature range at the magnetic transition is more adequate for a refrigerant cycle than that at the structural transition.