DISPLACEMENT AND EMISSION CURRENTS FROM PLZT-8 65/35 AND PLZT-4/95/5 EXCITED BY A NEGATIVE VOLTAGE PULSE AT THE REAR ELECTRODE/

It is shown that nonprepoled PLZT ceramics, both in ferroelectric and antiferroelectric phase, emit intense current bursts when a negative e xciting voltage is applied to the rear surface of the cathode. The spo ntaneous polarization induced in the bulk by applying the field throug h the cathode disk, creates a sheet of negative charge on the diode bo undary of the ferroelectric. This, in turn, induces such a high electr ic field at the diode dielectric surface that electrons are ejected ou t from the ceramic surface into the vacuum. The coherent behaviour of the displacement and emitted current shows dearly that the emission is due to a variation of spontaneous polarization. A second effect gener ated by the application of the high voltage pulse at the rear side is the formation of a surface plasma. Applying a positive voltage to the anode, electrons are readily transferred through the diode gap.