Electron emission from PZT ferroelectric cathodes under strong accelerating field

Summary form only given. We have studied emission characteristics of a PZT ferroelectric cathode under influence of a strong accelerating field by varying triggering conditions. The beam current pulse reveals a rising and a steady phase. In the rising phase, the time variation of the beam current is found to be linearly dependent on both the trigger voltage and the diode voltage at the time when the current starts. In the steady phase, the beam current becomes irrelevant to the trigger voltage. The beam current follows to three halves power of the diode voltage, which indicates the dominant emission process is a field emission. Same experiments have been repeated using two kinds of PZT materials, LZT-2 and APC850, with the same cathode geometry. The perveances of the electron guns differ by more than 100%. The difference of the emitted electron is found to be related to the difference of frequency characteristics of the materials, which implies that the electron emission is possibly caused by the domain oscillation in the vicinity of vacuum-ferroelectric-metal triple-junction. The experimental results provide a key-point, which may lead to a more complete understanding of electron emission from ferroelectric materials.