We report extensive experimental data on electron emission from lead-z
irconate-titanate ferroelectric ceramics. A 1-2 MV/m pulse is applied
to a gridded ferroelectric cathode and diode currents of up to 120 A/c
m(2) are measured across an A-K gap of 5 X 10(-2) m, with the anode at
35 kV. Both the current and the anode voltage pulse duration may exte
nd to several microseconds. The. measurements extend previously report
ed data by nearly two orders of magnitude in the diode voltage and by
a factor of more than 3 in the diode spacing. Two major regimes of ope
ration were identified. In the first similar to 1 mu s the ferroelectr
ic cathode controls the electron how through the diode. Beyond this ti
me plasma effects dominate the current flow. The results are of import
ance to the development of novel cathodes for high current electron be
am generation. (C) 1998 American Institute of Physics. [S0021-8979(98)
06401-9].