Current limiting and negative differential resistance in indium oxide based ceramics

Abstract

Abstract.Indium oxide based ceramics with bismuth oxide addition were sintered in air in the temperature range 800-1300 ºC. Current-voltage characteristics of In 2 O 3 -Bi 2 O 3 ceramics sintered at different temperatures are weakly nonlinear. After an additional heat treatment in air at about 200 ºC samples sintered at a temperature within the narrow range of about 1050-1100 ºC exhibit a current-limiting effect accompanied by low-frequency current oscillations. It is shown that the observed electrical properties are controlled by the grain-boundary barriers and the heat treatment in air at 200 ºC leads to the decrease in the barrier height. Electrical measurements, scanning electron microscopy and X-ray photoelectron spectroscopy results suggest that the current-limiting effect observed in In 2 O 3 -Bi 2 O 3 may be explained in terms of a modified barrier model; the observed current-limiting effect is the result of an increase of barrier height with increasing electric field, due to additional oxygen absorption. It is found that In 2 O 3 -Bi 2 O 3 -Co 3 O 4 -Cr 2 O 3 ceramic exhibits current-voltage characteristics with negative differential resistance due to Joule micro heating.

ize Effects in Electrical Properties of Carbon-Polypropylene Composites

“…Electric properties of polymeric composite materials can be varied in rather wide limits. This is one of their advantages in comparison with traditional inhomogeneous materials that are used as the element base of modern electronics, such as condenser [1,2], varistor [3,4], and posistor ceramics [5][6][7][8][9]. As a result, polymer composites with different characteristics can be obtained on the basis of the same initial substances.…”