Ni-Mn-Sn ferromagnetic shape memory alloys (FSMAs) have promise for application in efficient solid-state refrigeration. However, the simultaneous achievement of giant magnetocaloric effect (MCE) and excellent mechanical properties and high working temperature in these materials is always the challenge. Computation-guided materials design techniques provide an efficient way to design and identify new magnetocaloric materials. Herein, a new strategy of multidoping is presented. First, we conduct a detailed and comprehensive first-principles study and predict that Ni-Mn-Sn FSMAs with co-doping 6.25 atom % Cu and 6.25-12.5 atom % Co can realize the multiobjective optimization of magnetocaloric material. Then, it is confirmed by experiment and we report on Ni40Co8Mn37Sn9Cu6 FSMA exhibiting a large magnetic entropy change (34.8 J/(kg K)) of a large value in the prevalent MCE materials at high temperature (∼344 K) and whose compression stress and strain (∼1072.0 MPa and ∼11.9%) are both the largest among Ni-Mn-based MCE materials. Notably, the effect of Co and Cu doping is not simply stacked because they play opposite roles in Curie temperature (TC) and martensitic transformation temperature (TM). So, achieving the balance of their effect to combine their merits in a very narrow window is the key step. This approach of multielement doping holds promise to be extended to other magnetocaloric materials to enhance their multiple properties simultaneously.
Keywords: Ni−Mn−Sn alloy; high temperature; magnetocaloric effect; mechanical properties; multielement doping.