Phase transitions and magnetic properties of Ni(Co)-Mn-Al melt-spun ribbons

We have studied the influence of Cobalt addition on phase transition temperatures and magnetic properties of melt-spun ribbons of Ni50−xCoxMn31+yAl19−y (x = 0-10, y = 0-3) magnetic shape memory alloys. It was found that addition of Co has a marked influence on the magnetic properties as well as martensitic transformation temperature of the ribbons. Specifically, as compared to a weakly magnetic Co-free (x, y = 0) sample, the Ni50−xCoxMn31+yAl19−y (x = 5, 10) ribbons demonstrate ferromagnetic properties. The Ni45Co5Mn32Al18 sample was found to exhibit a well-defined metamagnetic transformation. Thus, our results can be considered as a successful development of metamagnetic shape memory ribbon in the Ni(Co)-Mn-Al system.