Nanowires of iron

Nanowires of iron have been fabricated using atom-optics techniques. An atom in a light field of an appropriate wavelength will acquire an electric dipole moment, which in turn can interact with the light field. Only a few atomic species have been amenable to such coupling, and now iron—a ferro-magnet—has joined the list. Two independent groups, both in the Netherlands, sent a collimated beam of iron atoms into an optical standing-wave pattern, in which the atoms were preferentially drawn into either the minima or the maxima. Thus positioned, the atoms were deposited onto a substrate. The image here (from the group at Radboud University in Nij-megen) shows 95-nm-wide wires, each about 8 nm high. A full array of 8600 iron lines, about 400 µm long, was grown in a half hour. With a better-collimated atom beam, the Eindhoven University of Technology group grew iron wires that were only 50 nm wide...