Composition-controlled synthesis, structure and magnetic properties of ternary FexCoyNi100−x−y alloys attached on carbon nanotubes

FexCoyNi100−x−y alloy nanoparticles with controllable compositions attached on the surface of carbon nanotubes (CNTs) were synthesized using an easy two-step route including adsorption and reduction processes. The nanocomposites have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy-disperse X-ray spectroscopy (EDS) and vibrating sample magnetometer (VSM). The effect of the alloy composition on microstructure and magnetic properties of ternary FeCoNi alloys attached on carbon nanotubes have been studied. During the nominal composition range (x = 21, 24, 33, 37, 46 and y = 60, 46, 48, 48, 35), FexCoyNi100−x−y alloy nanoparticles attached on CNTs are quasi-spherical, fcc–bcc dual phase, and the coercivity (Hc) and saturation magnetization (Ms) vary with the alloy composition. The Hc of FexCoyNi100−x−y alloy nanoparticles attached on CNTs decreases and Ms increases with increasing Fe content. These demonstrate that the two-step route is promising for fabricating alloy nanoparticles attached on CNTs for magnetic storage and ultra high-density magnetic recording applications.