Electrical properties of n-type BaTiO/sub 3/ ceramics with respect to its current-limiting effect

Electrical properties of n-type BaTiOa ceramics are reported at moderate temperatures in the range 350-470 K. The positive temperature coefficient of resistance (PTC) effect was studied under an electrical field in the range of 0.4-125 V/mm. The current-limiting effect of the material was studied by measuring the static current density (i) vs electrical field (E) under both ac and dc conditions. The response time to limit a high dc current was measured. A strong dependence of PTC effect on the applied electrical field was observed. The implication of such dependence on the observed current-limiting behaviour is discussed. The maximum electrical field which could be applied to the material was found to be limited by a thermal crack effect.