AbstractWe report nanometer-scale ordered arrays of cylindrical magnetic nanoparticles with low aspect ratio and ultra-high uniformity. Protracted anodization provides hexagonally ordered nanopores in amorphous Al2O3. For instance, pulsed electrochemical deposition grows Co particles of uniform length from the bottoms of these pores: these particles are polycrystalline and randomly oriented. The magnetism of the array is dominated by particle shape and by inter-particle magnetostatic interactions. A very clear transition of the anisotropy from perpendicular to in-plane is observed at a height to radius ratio of about 2. This pulse-reverse electrodeposition shows great promise for a reliable synthesis of uniform nanostructures of many metals.
Surface lattice resonances and magneto-optical response in magnetic nanoparticle arrays