Ferromagnetism in nanotubes controlled by electron/hole doping

Spintronics requires fabrication of magnetic nanostructures, therefore we synthesized a distinctly structured open-net layered-wall vanadium oxide (VO_x) nanotubes, using the, so called, ´chimie douce´ techniques. We discovered that these nanotubes can be easily spin-tuned by charge doping. By adding either electrons (e.g. doping with lithium) or holes (e.g. doping with iodine) to this multiband strongly correlated system, we found that the initially spin-frustrated nanotubes develop a nearly identical nonlinear ferromagnetic spin response. Based on complex structure of VO_x nanotubes, we developed a model explaining how either electron (Li) or hole (I) doping can produce an identical magnetic response in such layered low-dimensional objects.