Non-Ohmic conduction in tin dioxide based varistor ceramics

Current limiting and negative differential resistance in indium oxide based ceramics

“…The current limiting effect observed in the In 2 O 3 -Bi 2 O 3 ceramics studied here is markedly different from the electrical properties of ZnO-Bi 2 O 3 -based [20,22] or SnO 2 -Bi 2 O 3 -based ceramics [21,23,24], which exhibit the varistor effect. In both groups of materials the grain-boundary barriers play the main role in the conduction process.…”

“…Earlier currentvoltage characteristics with switching or negative differential resistance were observed in various nonoxide and oxide systems (see, for example [34,35]). …”

“…In both groups of materials the grain-boundary barriers play the main role in the conduction process. The varistor effect in ZnO-based and SnO 2 -based materials is related to the lowering of the barrier height with increase in electric field [30][31][32][33][34]. But perhaps the feature of barriers to be decreased (in varistor ceramics) or increased (in ceramics with current limiting behaviour) with the application of voltage depends on the specific impurities at the grain boundaries.…”

“…Indium oxide exhibits n-type conduction and is widely used for the preparation of transparent electrodes for optoelectronic devices [13][14][15] and gas-sensors [16][17][18]. However, it is well known that the addition of bismuth oxide (Bi 2 O 3 ) improves the sintering and promotes an increase in the nonlinearity coefficient in zinc oxide based and tin dioxide based varistor ceramics [19][20][21][22][23][24]. This suggests that bismuth oxide addition may also induce non-ohmic behavior in indium oxide ceramics.…”

Non-ohmic conduction in tin dioxide based ceramics with copper addition

“…Quite high non-ohmic conduction was also observed in tin dioxide (SnO 2 ) based ceramics [3,4]. This observation means that ZnO ceramics are not unique materials with highly nonlinear current-voltage characteristics.…”