Voltage-current characteristics of vanadium dioxide based ceramics

Voltage-current characteristics of VO2 and V2O5–P2O5 glasses based ceramics with an addition of copper has been studied. The voltage-current characteristics are of S-type and have behaviour, which is typical for materials on the basis of vanadium dioxide. At some voltage the switching takes place and in a ceramic sample is formed the channel of electrical current. The VO2 crystallites in this channel are in a metallic phase. The analytical expression for a voltage-current characteristic of a ceramic sample with the cylindrical channel of electrical current is obtained. The effective electrical conductivity and effective thermal conduction of vanadium dioxide based ceramics are increasing, the switching voltage is decreasing at increase of the content of copper additive. The probable reason of that is increase of amount of electrical and thermal bonds between VO2 crystal grains through inclusions of copper, and also the decrease of a porosity of ceramics.