Nanotube magnets
The scientists from IBM's TJ Watson Research Center in New York state see potential spintronic applications in nanotube-based heterostructures.
Previous nanotube research has concentrated on electronic conduction. "This is probably due to the relative paucity of nanometre-scale ferromagnetic building blocks," the scientists comments.
The initially spin-frustrated VnOx nanotube semiconductors become ferromagnetic through either electron (lithium from a commercial SAES Getter source) or hole (iodine vapour) doping. The magnetisation at 300K (room temperature) saturates at around 1kOe. The thermal behaviour of this saturation is typical of a ferromagnet with a Curie temperature (TC) of 500K. TC is where the material becomes non ferromagnetic.
The self-assembly is directed using dodecylamine (CnH2n+1NH2, with n=12), a surfactant molecule, with vanadium tri-isopropoxide (VO(iOPr)3) in ethanol.
