Abstract
Negative resistance, conductive switching and memory effect are found in a-ferric oxide ceramics con-taining several kinds of oxide, ZnO, Bi2O3, CuO, etc. Same effects are also found in pure a-ferric oxide ceramics. It has been considered, therefore, that these effects are caused only by the nature of the system Fe-O, and these contained impurities play only subsidiary role such. as changing the equilibrium pressure of oxygen in the specimen.
Currents both in conductive state ("on-state") and in resistive state ("off-state") flow through the filamentary conductive path grown by electrical "forming". Current-voltage characteristics depend on the surrounding temperature and partial pressure of oxygen, but no electrode effect is found.
The mechanisms of electrical conduction have not been understood sufficiently, but the formation of filamentary conductive path has been found experimentaly. It seems that chemisorbed oxygen at the formed filament plays a great part to these characteristics of switching and memory effect. (Received August 8, 1974)
