Tailoring of the c-axis orientation and magnetic anisotropy in electrodeposited Co nanowires

The magnetic properties of arrays of electrodeposited Co nanowires have been studied by ferromagnetic resonance as a function of the electrolytic bath acidity and the plating current intensity. It is observed that by adjusting the pH or the plating current it is possible to find appropriate electrolyte-deposition conditions which lead to the deposition of Co nanowires with a c-axis orientation either parallel or perpendicular to the wires. At relatively high plating currents, systems containing a dominant fraction of grains having the c-axis oriented perpendicular to the wires are favoured. Such wires show a significant decrease of the effective anisotropy due to the competition between the magnetocrystalline and the shape anisotropy that can be as low as 4.3 kOe. In contrast, at low plating currents the c-axis is aligned parallel to the wires and an effective anisotropy field, that can be as high as 12 kOe, is observed.