Influence of fabrication conditions on giant magnetocaloric effect of Ni–Mn–Sn ribbons

Abstract

The magnetocaloric effect of Ni50Mn50−xSnx ribbons (x = 11–15) prepared by using melt-spinning and subsequent annealing has been investigated. The x-ray diffraction data of specimens show that all the samples are partially crystallized with Ni2MnSn phase. The magnetic transitions of these ribbons strongly depend on Sn-concentration and annealing process. Particularly, the antiferromagnetic–ferromagnetic transition is just observed at a narrow range of the Sn-concentration (x = 12–14). The positive magnetic entropy changes occurring at the transition temperature of the antiferromagnetic phase are quite large, |ΔSm|max = 5.7 J kg−1 K−1 (for x = 13) with external magnetic field change ΔH = 12 kOe. Besides that, the negative magnetic entropy changes take place near Curie temperature and their magnitude is also large, |ΔSm|max = 1.9 J kg−1 K−1 (for x = 13). The obtained results indicate that Ni50Mn50−xSnx ribbons are good candidates for magnetic refrigeration application at room temperature.