Novel Synthesis and Magnetic Properties of PVP Capped Cobalt Nanostructures

Novel polyol methodologies (named as: route-1 and route-2) have been developed for synthesis of PVP capped nanostructured Co in organic (DMF) medium at lower temperature of 110oC. Co nanoparticles (nps) crystallize in hcp and fcc structures with average crystallite size of 16.4 nm and 37.1 nm, for route-1 and route-2, respectively. TEM micrographs show chain-like and nearly spherical nanostructures for Co nps synthesized via route-1 and route-2, respectively. We could obtain the maximum value of MS and Hc, i.e., 167 emu/g and 357 Oe, respectively, for nanostructured Co synthesized via route-1 at 100 K. Variations in saturation magnetizations (Ms) and coercivity (Hc) values have been explained mainly on the basis of fine particle size, shape, surface and altered crystal anisotropies.