Martensitic transformation behaviors and magnetic properties of Ni-Mn-Ga rapidly quenched ribbons

In this paper, the phase transformation behaviors and structures of Ni₅₀Mn_28 + xGa_22 − x (x = 0, 1, 2, 3) alloys and ribbons as well as the magnetic properties of ribbons are discussed. Rapidly quenching process decreases the degree of order and introduces some internal stress, which influences the martensitic transformation temperatures of the ribbons. The structures of the ribbons become 7 M modulated, which is different from the 5 M modulated martensite of the corresponding bulk materials. Higher annealing temperature and annealing under magnetic field are all in favor of the magnetization of the ribbons, and this is related to the enhancement of orientation perpendicular to the surface of the ribbons.