Emission from ferroelectric cathodes versus temperature and the relevant physics

We show that electron emission from a relaxer ferroelectric cathode varies with the temperature as the dielectric constant. Consequently, there is no variation when the material makes the antiferroparaelectric phase transitio n. In addition, we have found that the emission increases with the polariza bility of the material. The emission is originated by an induced change of the normal and/or spontaneous polarization. The maximum efficiency of the p rocess, that is the ratio between the emitted charge of energetic electrons and the charge supplied to the sample by the excitation pulse, resulted in about 20%. The good emission of energetic electrons from a ceramic cathode at few hundred degrees temperature, makes this kind of cathode a proper el ectron injector for ion sources. (C) 2001 American Institute of Physics.