Vanadium dioxide nanobelts: Hydrothermal synthesis and magnetic properties

VO2 (B) nanobelts were prepared by a hydrothermal method at 180 degrees C using V2O5 center dot nH(2)O sol and H2C2O4 center dot 2H(2)O as starting agents. The obtained nanobelts have diameters ranging from 50 to 100 nm in width, 20-30 nm in thickness with lengths up to 1.5 mu m. Measurements of the static magnetic susceptibility provide evidence for two phase transitions at T-1 = 225 K and T-2 = 290 K, respectively. Below T-1, the data suggest the presence quasi-free as well as of strongly antiferromagnetic correlated spins associated to V4+-ions. (C) 2010 Elsevier Ltd. All rights reserved.