Charge and spin dynamics in VO2 nanorods

Electrical conductivity and photoconductivity measurements were carried out on vanadium dioxide (VO2) nanorods prepared by the hydrothermal treatment of vanadium pentoxide gels. While the structural properties of the nanorods resembled those of the Cr-doped VO2, the charge and spin dynamics appears to resemble those of the Nb-doped VO2. The magnetic and (photo)electrical properties of the nanorods can be understood in terms of localization of itinerant electrons giving rise to a spin-polarized (S=3/2) V4+ pair, dominant at higher temperatures, or to a (S=1) V3+ ion out of a V4+ ion pair, dominant at lower temperatures.