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 but had a low contrast with the background substrate—they were just 0.6 nm high. Magnetic nanostructures can offer new possibilities for data storage, spintronics, and novel phenomena like magnetic bandgaps. (G. Myszkiewicz et al. , Appl. Phys. Lett. 85 , in press. E. te Sligte et al. , Appl. Phys. Lett. 85 , in press.)