Study of amorphous Co56Nb22Sn22 alloy prepared by mechanical alloying

The Co2NbSn Heusler phase has been extensively studied due to its structural and magnetic properties, mainly because it shows a martensitic transition at 250 K. An amorphous Co56Nb22Sn22 phase has been produced by mechanical alloying starting from the blended highly pure Co, Nb, Sn elemental metal powders with the Co2NbSn nominal composition. Its local atomic order has been compared with that present in the Co2NbSn compound. For that, the total radial distribution function RDF(r) was obtained by Fourier transforming the total structure factor S(K), derived from the measured X-ray diffraction (XRD) pattern. Magnetization measurements versus temperature shows pronounced irreversibility behavior below 48 K for external applied magnetic field of 20 Oe. A narrow hysteresis loop is observed for isothermal magnetization curve at 5 K for magnetic field between −0.3 T and 0.3 T. Its thermal properties such as crystallization temperature and activation energy, necessary to promote the amorphous–crystalline transformation, was also studied by differential scanning calorimetry measurements. A heat treated sample was investigated via XRD, and its pattern showed the Co2NbSn Heusler phase together with others unidentified minority phases.