Shape controlled synthesis of iron-cobalt alloy magnetic nanoparticles using soft template method

Fe_xCo_1 − x alloy nanoparticles of spherical (x = 0.25, 0.68, 0.85), hollow spherical (x = 0.60) and sheet like (x = 0.60) shapes were prepared at room temperature by reduction of iron chloride tetrahydrate and cobalt chloride hexahydrate with sodium borohydride, using N-Cetyl-N,N,N-trimethyl ammonium bromide (CTAB)/water/hexanol system as soft template. The size and shapes of nanostructures were found to depend on the concentrations of CTAB and hexanol in water. Composition and shape dependence of magnetic properties of spherical, hollow spherical and sheet like Fe_xCo_1 − x alloy nanostructures were discussed. The highest saturation magnetization of 235 emu/g with a coercivity of 160 Oe was obtained for spherical Fe_0.68Co_0.32 nanoparticles.