Enhancement of the martensitic transformation and magnetocaloric effect of Ni-Mn-V-Sn ribbons by annealing treatment

Abstract

The rapidly solidified Ni41.98Mn42.97V2.08Sn12.97 ribbons are prepared by the melt‐spinning technique. The microstructure, martensitic transformation (MT), and magnetocaloric effect of the ribbons are greatly affected by annealing treatment. The equiaxed crystallized grains with the relatively homogeneous size distribution are observed for these ribbons. After annealing, the grain size becomes obviously large, the lattice constants decreases, and the exchange bias effect gets improved. The MT temperatures increase obviously for the annealed ribbons. Large magnetic entropy change (ΔS) is obtained in the annealed Ni–Mn–V–Sn ribbons. The peak values of ΔS in the annealed ribbons are 41.6 and −2.3 J kg−1 K−1 in the vicinity of MT temperature and Curie temperature of austenite, respectively, for the field change of 30 kOe.

Magnetoresistance and exchange bias in high Mn content melt-spun Mn 46 Ni 42 Sn 11 Sb 1 alloy ribbon

“…[1] Later, there were several research groups which studied the magnetic properties and magnetoresistance (MR) in both NiMnSn and NiMnIn alloys. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In 2006, giant MR (50%) was obtained in Ni 50 Mn 34 In 16 alloys in a magnetic field of 1 T, [2] while the Ni 50 Mn 36 Sn 14 got the same level (50%) in magnetic fields up to 17 T. [3] Even though a larger MR can be obtained in the NiMnIn than that in NiMnSn alloys, the necessity to the success of commercial use lies in the low-cost materials being available. By comparing the price of nickel and manganese, a high manganese content of alloy composition can effectively reduce the production cost.…”