A Review on the Regulation of Magnetic Transitions and the Related Magnetocaloric Properties in Ni-Mn-Co-Sn Alloys

In Ni-Mn-X (X =In, Sn, Sb) ferromagnetic shape memory alloys, a ferromagnetic transition from paramagnetic to ferromagnetic austenite and a martensitic transformation from ferromagnetic austenite to weak magnetic martensite occur in some particular composition ranges, in which abundant physical properties have been observed by the abrupt change of magnetization and resistivity around their transition temperatures in these alloys. Therefore, tuning the martensitic transformation temperature (TM) and enlarging the working-temperature interval for Ni-Mn-X (X=In, Sn, Sb) alloys, are of great importance. In the present paper, we will focus on the effect of external factors, including pre-deformation, annealing, and high pressure annealing, on the magnetic transitions and the related magnetocaloric properties in Ni-Mn-Co-Sn ferromagnetic shape memory alloys. Our approaches and the main results in this particular field will be reviewed.