The influence of temperature hysteresis at metal-semiconductor phase transition on current-voltage characteristic of VO sub(2)-based ceramics

The current-voltage characteristics of ceramics (wt%) 80VO sub(2)-15VPG-5Cu and 45VO sub(2)-15VPG-5Cu-35SnO sub(2) were investigated (VPG-vanadium phosphate glass). After switching to high electric current, these characteristics show a hysteresis loop in the electric current increase-decrease cycle. The cause of hysteresis is the different phase transition temperatures in VO sub(2) crystallites for transition from semiconductor phase to metallic phase and for the reverse transition. The distinction of phase transition temperatures leads to the different equilibrium temperatures in the filament of the metallic VO sub(2) phase, when 'electric current increases and decreases. As the result, different power dissipated by electric current in ceramics sample is necessary for ensuring thermal equilibrium in the filament. This is the reason why current-voltage characteristic registered at electric current increase do not coincide with characteristic registered at electric current decrease.