Synthesis, morphology, and magnetic properties of NiCo/carbon nanocomposites

Depending on the Ni:Co molar ratio, composites of NiCo/carbon nanorods and NiCo/carbon nanotubes can be synthesized through catalytic decomposition of benzene at 500 degrees C over NiCo nanoparticles derived from sol-gel synthesis followed by hydrogen reduction. According to x-ray diffraction results, the average grain size of NiCo31 is 11.2 nm, whereas that of NiCo13 and NiCo22 is 24.9 nm. Field-emission scanning electron microscopic and high-resolution transmission electron microscopic images reveal that over NiCo13 and NiCo22, the carbon nanomaterials are mainly in the form of nanorods, whereas over NiCo31, they are in the form of nanotubes. The composites of carbon and NiCo alloy are highly stable in air and show soft magnetic property and almost equal coercivity. It is observed that the saturation magnetization is affected by the composition of NiCo alloy.