Vanadium dioxide nanobelts: Hydrothermal synthesis and magnetic properties

Abstract VO 2 (B) nanobelts were prepared by a hydrothermal method at 180 °C using V 2 O 5 · n H 2 O sol and H 2 C 2 O 4 ·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 μm. 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 V 4+ -ions.