Martensitic transformation and inverse magnetocaloric effect in Ni-Mn-Ga-Co-Gd microwires

Ni–Mn-Ga-Co-Gd microwires were fabricated by the glass-coated melt spinning method, resulting in a bamboo-grained structure. In this paper, the magnetocaloric effect of Ni–Mn-Ga-Co-Gd microwires is mainly investigated, which is represented by the isothermal magnetic entropy change calculated using Maxwell equation. Specifically, Ni43Mn30Ga19.9Co7Gd0.1 microwires exhibit maximum entropy change of 11.09 J/kg·K under 5 T magnetic field, which is generally greater than that of the current Ni–Mn-Ga microwires. Additionally, Ni43Mn30Ga19.9Co7Gd0.1 microwires show the temperature corresponding to the greatest magnetic entropy change nearer to room temperature compared to other Ni–Mn-Ga microwires. Furthermore, the larger specific surface area of microwires will facilitate their application in the field of magnetic refrigeration.