Fabrication and characteristics of ordered Ni nanostructures on glass by anodization and direct current electrodeposition

A novel process for fabrication of metal nanostructure arrays directly on glass substrates is described. An aluminum film was sputter-deposited on a glass substrate coated with a tin-doped indium oxide (ITO) film. The films were then anodically oxidized to obtain a porous alumina template, with pore diameters ranging from 5 to 150 nm, which was used as a template-electrode in a direct current electrodeposition to fabricate various nickel nanowires (diameter 18-180 nm, 0.5-2.6 mum long) in the nanopores. The porous alumina films not only define the dimensions of the nanowires but also influence the crystalline orientation. The magnetic hysteresis measurement showed that the Ni nanowire arrays have significant magnetic anisotropy proportional to their aspect ratios. The coercivity (H-c) and the squareness (M-r/M-s) perpendicular to the substrates were 1025 Oe and 0.74 for the Ni nanowires of diameter 50 nm (1.8 mum), and 830 Oe and 0.94 for the Ni nanowires of diameter 18 nm (1.2 mum), respectively.