Controlled synthesis, structure and magnetic properties of Fe1 − xNix alloy nanoparticles attached on carbon nanotubes

Fe1 − xNix alloy nanoparticles (x = 0.25, 0.50, 0.75), with diameters in the range of 12–15 nm were uniformly attached on the surface of carbon nanotubes by wet chemistry, which were characterized by transmission electron microscopy, high-resolution transmission electron microscopy and X-ray powder diffraction. When x = 0.25, fcc and bcc structure coexist obviously, while when x = 0.50, 0.75, most of Fe1 − xNix alloy nanoparticles have fcc structure. Fe1 − xNix alloy nanoparticles attached on carbon nanotubes have soft magnetic in nature, and the coercivity decreases with increasing Ni concentration and with decreasing the nanoparticles size, the saturation magnetization varies with the Ni concentration changes. These demonstrate that the chemical method here is promising for fabricating Fe–Ni alloy nanoparticles coated on carbon nanotubes for magnetic storage applications.