ELECTRON-EMISSION OF (PB, LA) (ZR, TI) O3 CERAMICS EXCITED BY AC (50 HZ) ELECTRIC-FIELD

AC field-excited electron emission from 5.1/65/35 and 10.4/64/36 PLZT ceramic samples is investigated. The electrons are emitted only during every second half-period of the applied ac electric field. In the diffuse phase transition regions, the intensity of the electron emission for 5.1/65/35 ceramic samples increases with temperature and decreases for 10.4/63/36 ones. The time distributions of electrons emitted during the emissively active field half-period are also different. The mechanism of this electron emission, based on electron tunnelling from a surface space-charge layer into vacuum is discussed.