A Study of TaO Nanopillars with Ni Tips Prepared by Porous Anodic Alumina Through-Mask Anodization.

The paper discusses the formation of TaO pillars with Ni tips during thin porous anodic alumina through-mask anodization on Si/SiO substrates. The tantalum nanopillars were formed through porous masks in electrolytes of phosphoric and oxalic acid. The Ni tips on the TaO pillars were formed via vacuum evaporation through the porous mask. The morphology, structure, and magnetic properties at 4.2 and 300 K of the TaO nanopillars with Ni tips have been studied using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The main mechanism of the formation of the TaO pillars during through-mask anodization was revealed. The superparamagnetic behavior of the magnetic hysteresis loop of the TaO nanopillars with Ni tips was observed. Such nanostructures can be used to develop novel functional nanomaterials for magnetic, electronic, biomedical, and optical nano-scale devices.