3D distribution of magnetic CoNi alloy nanoparticles electrodeposited on vertically aligned MWCNT showing exceptional coercive field

• Functionalization of vertical aligned carbon nanotubes to favor electrodeposition.
• Electrodeposition of magnetic nanoparticles maintaining aligned carbon nanotubes.
• 3D distribution of CoNi nanoparticles on carbon nanotubes.
• Electrochemical control of size and crystalline structure of CoNi nanoparticles.
• Hcp CoNi nanoparticles (70 nm) in carbon nanotubes showing exceptional coercivity.

A novel, fast and simple method to achieve a 3D distribution of CoNi nanoparticles (NPs) by electrochemical deposition on vertically aligned multiwall carbon nanotubes is described. Alignment is maintained during the electrodeposition. This method allows to easily obtain magnetic anchored, no aggregation, nanoparticles spatially distributed almost homogenously in a thick 3D structure (10 µm). Potential and charge of deposition condition size, composition and crystalline structure of the CoNi NPs and then the magnetic properties of the NPs/CNTs structures. The structures with hcp CoNi NPs of around 70 nm obtained at low deposition potentials present an exceptional high coercive magnetic field (higher than 1 kOe), never previously found for CoNi NPs. Structures with hcp+fcc CoNi NPs present lower coercivity, which corresponds to the lower magnetic anisotropy of the fcc crystalline phase.

Figure optionsDownload as PowerPoint slide