Highly ordered magnetic Ni nanotubules (see Figure) have been successfully prepared. Electrodeposition in the pores of an alumina membrane modified with an organoamine as pore‐wall modifying agent results in a perfectly ordered array of such metal nanotubules tens of micrometers long. These metal nanotubules with open ends could be employed for the creation of materials with special magnetic, optical, or electrical properties.

Metallic nanowires protected from oxidation and corrosion by a sheath of polyaniline have been prepared in arrays on an alumina membrane support. The cobalt wire/polyaniline tubule nanocomposite structures (see Figure), which are produced by using the polyaniline tubules as a template for the growth of the metal wires, have potential in applications such as magnetic antenna materials.

Cobalt‐filled carbon nanotube composites (see Figure) with a high metal‐filling ratio can be prepared by a simple and effective method. The length, diameter, and structure of the metal‐filled nanotubes and the wall thickness of the plain carbon nanotubes can be easily controlled by the template used and synthesis conditions. Magnetic measurements reveal that the array of cobalt‐filled carbon nanotubes exhibits enhanced coercivities in comparision to that of bulk Co.

An array of single crystal CdS nanowires has been fabricated in the pores of an alumina membrane by sol–gel synthesis. The CdS crystals have a hexagonal structure, which is verified by electron diffraction. As CdS is an important semiconducting material this synthesis may prove very useful for the fabrication of nanosized semiconducting structures. The Figure shows a scanning electron microscopy image of the nanowires.

An array of nickel nanowires enveloped in polyaniline nanotubules was prepared by the “second-order-template” method. As the first step, an array of the polyaniline nanotubules was synthesized in the pores of an alumina membrane, then nickel nanowires were fabricated by electrochemical deposition of the nickel into the polyaniline nanotubules. The composite nanostructure was characterized by x-ray powder diffraction, and scanning electron micrography. Its magnetic properties were measured by a vibrating sample magnetometer. The coercivity and remanence are of high anisotropy with a maximum at θ=90° (parallel to the nanowires).

Zirconia nanotubules, filled with crystalline cobalt rods (see Figure), were prepared in a reaction sequence of sol–gel crystallization of ZrO2 from zirconyl chloride octahydrate around a template of commercial porous anodic alumina, followed by electrodeposition of cobalt from CoSO4 solution and template removal with 6 N NaOH. The composite shows uniaxial magnetic anisotropy and a coercivity exceeding that of bulk cobalt.