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Solid state refrigeration technology relies on the high-performance materials with remarkable caloric properties. Here, we demonstrate a large elastocaloric effect through stress-induced martensitic transformation in a Heusler-type Co50V35Ga14Ni1 polycrystalline alloy. By rapidly removing a moderate compressive stress of 400 MPa, a large adiabatic temperature change up to −12.1 K is achieved. Moreover, high cyclability of the elastocaloric effect with more than 4000 loading/unloading cycles is also obtained. With the combination of a large elastocaloric effect and good cyclability, Co-V-Ga based alloys hold great potential for environment-friendly solid-state refrigeration applications.

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The structures, martensitic transition, and magnetic and electronic properties of Mg8VxGa8−x (x = 2, 3, 4, 5, 6) Heusler alloys were investigated using first-principles calculations. The structures for the substitution of extra atoms for deficient atoms are not energetically favorable. The strength and quantity of the interatomic bonds determine the lowest energy structures of compounds. With the increase in x, the lattice constants do not change monotonously, which is related to the shifting of the accumulated electrons in the covalent bonds. The magnetic moments of extra V are antiparallel to that of V at the normal sites. In the process of tetragonal deformation, the magnetic moment of V is closely related to the distance from the other V atoms. The martensitic transition may occur in all of the compounds studied herein. The splitting of the V d orbital indicates that the transition is due to the structural Jahn-Teller effect.