Abstract
In our research, the first important goal was to prepare highly ordered array structures. Then, we used the above array structures as the template to prepare the nanoarray and nanoporous array structures with the electrodeposition process that has the advantages of being simple and low cost. First, we prepared the polystyrene (PS) sub-micron particles of different sizes (250nm, 320nm, 400nm, 440nm) by means of the emulsifier-free emulsion polymerization and the highly ordered PS opal arrays by means of the vertical deposition. Second, the above mentioned PS opal array was treated as the initial template to prepare the low conductive polypyrrole (PPy) inversed opal network array with the plating polymerization and thermal treatment for un-doping the PPy. Furthermore, by means of anodization, the starting material, aluminum, was etched at different intensities of voltage and different concentrations of electrolyte and was transformed into highly ordered hexagonal pattern templates. Two different pore sizes, 20 and 50 nm, anodized alumina oxide membranes were prepared. Following, under the assistance of the 440nm pore size PPy inversed opal we prepare the metal tin opal array in advance after plating, and transform it to the porous tin oxide opal array by means of the anodization. The pore size is a range from 20nm to 40nm and the porous tin oxide opal has the high specific surface area (196 m2g-1). We then prepared three kinds of permalloy structures. They were the opal, inversed opal, and nanorod array structures. We discussed the magnetic properties of the three types of permalloy structures. The plating-synthesized permalloys possessed anisotropic shapes. The results showed that the coercivity gradually increased as the characteristic length of the arrays decreased in all different structures. Among the three different array structures, the nanorod array exhibited the highest coercivity intensity because of its high aspect ratio. As for the inverse opal array, it showed lower coercivity intensity because of the influence of domain wall pinning effect. The opal array possessed the lowest coercivity due to its large characteristic length scale similar to that of the bulk film material. Hence, one can vary the structure of permalloy to make it possess different magnetic properties because of the shape anisotropy of the structure.