Structure stability driven large magnetocaloric response in Ni-Co-Mn-In-Si Heusler alloy

Ni-Mn-In Heusler alloys have received considerable attention in the field of magnetic refrigeration owing to their eco-friendliness and large magnetocaloric (MC) response. In this paper, samples of Ni45Co5Mn37In12Si1 thus heat-treated for 0 h and 15 h have prepared by means of arc-melting followed by quenching. X-ray diffraction analysis confirms L2(1)-type crystal structure and stabilization of austenite phase at room temperature. FE-SEM equipped with EDS reveals the surface morphology and elemental composition of 15 h heat-treated Ni45Co5Mn37In12Si1 alloy with well-distinguished larger grains and a dendritic structure. Thermomagnetic measurements of 15 h heat-treated Ni45Co5Mn37In12Si1 shows the magnetostructural transition T-C(M) at the temperature of similar to 262 K and Curie temperature of austenite, T-C(A) was found to be above similar to 396 K with increase in the annealing time. Metamagnetic behavior and magnetic hysteresis are seen in isothermal magnetization curves. Interestingly, a large change in magnetic entropy Delta S-M similar to 9.3 J kg(-1) K-1 was obtained with refrigeration capacity (RC) of similar to 416.6 J kg(-1) under an applied field change of 5T with a broad temperature window of similar to 86 K for Ni45Co5Mn37In12Si1 alloy thus annealed for 15 h which makes it to be suitable for magnetic refrigeration applications.

Automated summary

Ni-Mn-In Heusler alloys have attracted considerable attention in magnetic refrigeration due to their eco-friendliness and large magnetocaloric response. This study found that the Ni45Co5Mn37In12Si1 alloy, heat-treated for 15 hours, exhibited larger grains and a dendritic structure, along with a significant change in magnetic entropy and refrigeration capacity, making it suitable for magnetic refrigeration applications.