Electrical and magnetic effect of transition metals in SnSb nanoalloy

Influence of incorporating transition metal impurities such as Fe, Co and Ni on the magnetic and electrical properties of SnSb alloy nanopowders synthesized by reductive co-precipitation is reported. Structural elucidation of all the samples by X-ray diffraction (XRD) confirms hexagonal structure and the morphological observations through scanning electron microscope (SEM) show a minimal particle size of 20 nm for the Co substituted SnSb sample, among all the other impurity incorporated samples. Compositional confirmation of Sn, Sb, Fe, Co, and Ni was made using EDAX. The X-ray photoelectron spectroscopy (XPS) is used to investigate the surface of SnSb and the change in surface activity due to the addition of transition metal impurities. The magnetic hysteresis studies indicate that SnSb and SnSb:Ni exhibit diamagnetic behaviour; while the Fe and Co incorporation resulted in ferromagnetic nature. The conductivity of SnSb:Fe, SnSb:Ni shows a semiconducting nature with negative temperature coefficient of resistance; whereas pure and Co substitution exhibit metallic behaviour with positive temperature coefficient of resistance. The switching of metallic to semiconducting regime is explained in this paper. Also an attempt has been made to correlate electrical and magnetic properties with the surface oxidation effect through XPS data.