Decomposition in Ni-Co-Mn-In functional Heusler alloys and its effect on shell-ferromagnetic and magnetocaloric effects

Ni-Co-Mn-In Heusler-based compounds are interesting for their magnetocaloric properties and have been widely investigated for this purpose. For Co compositions more than 5 at% in (${\mathrm{Ni}}_{100\ensuremath{-}x}{\mathrm{Co}}_x{)}₅₀{\mathrm{Mn}}_25+y{\mathrm{In}}_{25\ensuremath{-}y}$ the material is no longer single phase, and for $y<25$, shell-ferromagnetic precipitation occurs. Our study is twofold: First we study here the shell-ferromagnetic properties of these systems and show that their ferromagnetic exchange can be strengthened by introducing Co into the precipitate. Second, we further show that both the multiphase character and shell-ferromagnetic precipitation have strong implications on the magnetocaloric properties.