Electron spin resonance of vanadium-oxide nanotubes

Vanadium-oxide nanotubes, synthesized through hydrothermal treatment of a vanadium oxide-alkylamine composite, were studied by means of electron spin resonance (ESR). The ESR spectra were composed of a broad Lorentzian line superposed by a hyperfine structure, from which the uniaxial g-tensor and the hyperfine coupling tensor were obtained both for the nanotube and the composite. The eight-line hyperfine splitting structure appears to indicate that the 3d electrons of the V ⁴⁺ nuclei interact with only one vanadium nucleus and, thus, are strongly localized. The hyperfine splitting in the nanotubes was much greater than it was in the V ₂O ₅ single crystal, which is apparently ascribable to the curvature of the vanadium-oxide layers.