Conductivity Injection and Extraction in Polycrystalline Barium Titanate

Abstract

Direct current electric fields applied to polycrystalline barium titanate cause slow changes with time of current, potential distribution, and coloration. At temperatures between 250° to 300°C and with several thousand volts/cm applied, the current increases initially, then decreases, and then increases again. An analysis of the potential distribution indicates injection of a high conductivity region from the cathode, whereby the field at the cathode is decreased and the field at the anode is increased, followed by injection of a low conductivity region from the anode which travels to the cathode, causing a high field at the cathode and renewed injection of high conductivity from the cathode. Drift mobilities for the low conductivity region have been estimated.