Copious electron emission from PLZT ceramics with a high zirconium concentration

Gundel, Hartmut; Riege, H.; Wilson, E. J. N.; Handerek, J.; Zioutas, K.

doi:10.1080/00150198908007895

Cited by 108 publications

(39 citation statements)

References 16 publications

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“…Strong electron emission from ferroelectric (FE) materials, stimulated either by short electric field pulses (field direction from the emitting surface of the cathode towards the rear surface) or by laser light pulses or by a combined electrical-optical stimulation has been observed and studied since 1987 [1][2][3][4][5][6] at CERN. Emission with ferroelectric cathodes but with opposite direction of the exciting field is presently under investigation in many laboratories [7][8][9][10][11][12][13].…”

Section: -Introductionmentioning

confidence: 99%

“…When the spontaneous polarization P s within the material is directed towards the front electrode [the positive end {+} towards the grid electrode], the excitation of the sample is normally made by applying a negative HV pulse on the rear electrode [1][2][3]. The prepoling process creates, in addition to the spontaneous polarization P s , a space charge polarization P SC , due to the induced migration of defects (oxygen and lead vacancies) to the external surfaces.…”

Section: -Introductionmentioning

confidence: 99%

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Electron emission from ferroelectric/antiferroelectric cathodes excited by short high-voltage pulses

Benedek

Boscolo

Handerek

et al. 1997

Journal of Applied Physics

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Un-prepoled Lead Zirconate Titanate Lanthanum doped-PLZT ferroelectric cathodes have emitted intense current pulses under the action of a high voltage pulse of typically 8 kV/cm for PLZT of 8/65/35 composition and 25 kV/cm for PLZT of 4/95/5 composition. In the experiments described in this paper, the exciting electric field applied to the sample is directed from the rear surface towards the emitting surface. The resulting emission is due to an initial field emission from the metal of the grid deposited over the emitting surface with the consequent plasma formation and the switching of ferroelectric domains. These electrons may be emitted directly from the crystal or from the plasma. This emission requires the material in ferroelectric phase. In fact, PLZT cathodes of the 8/65/35 type, that is with high Titanium content, showing ferroelectric-paraelectric phase sequence, emit at room temperature, while PLZT cathodes of the 4/95/5 type, that is with low Titanium content, having antiferro-ferro-paraelectric phase sequence, emit strongly at a temperature higher than 130°C.

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Section: -Introductionmentioning

confidence: 99%

Section: -Introductionmentioning

confidence: 99%

Electron emission from ferroelectric/antiferroelectric cathodes excited by short high-voltage pulses

Benedek

Boscolo

Handerek

et al. 1997

Journal of Applied Physics

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“…1). The charge separation can be induced by applying a fast temperature rise [2], a mechanical pressure pulse (formerly used in fire lighters), a laser pulse [5] or a high-voltage (HV) pulse [3], [4], and [6] to the FE sample. With all these different excitation methods a fast change (switching) of the spontaneous FE polarization P s is induced, which is equivalent to the momentary appearance of high surface charge densities.…”

Section: Basic Features Of Fe Emissionmentioning

confidence: 99%

“…3), determine the field distribution on the emitting surface before and after polarization switching [15]. Therefore the electrodes must be matched to thick [3] and thin-film FE samples differently. Important parameters are FE porosity and surface roughness: if the surface is too smooth the electrodes adhere badly, if it is not well polished or etched, the field enhancement at holes or scratches may lead to sample perforation by the applied HV pulses.…”

Section: Technological Aspectsmentioning

confidence: 99%

“…Only a few of them could be examined more carefully and are dealt with below. The choice of the FE cathode material, the preparation methods, and the geometry of samples and excitation electrodes described in earlier references [3], [4], and [7], though not optimized, favoured strong FE emission. The density of switchable FE domains is very sensitive to heat treatments during the material production and sample preparation processes.…”

Section: Technological Aspectsmentioning

confidence: 99%

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Ferroelectric electron emission: Principles and technology

Riege¹

1997

Applied Surface Science

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The spontaneous electrical polarization of ferroelectric materials can be changed either by reversal or by phase transition from a ferroelectric into a non-ferroelectric state or vice versa. If spontaneous polarization changes are induced with fast heat, mechanical pressure, laser or electric field pulses on a submicrosecond time scale, strong uncompensated surface charge densities and related polarization fields are generated, which may lead to the intense selfemission of electrons from the negatively charged free surface areas of the ferroelectric sample. Hence, electron guns can be built with extraction-field-free ferroelectric cathodes, which may be easily separated from the high-field regions of post-accelerating gap structures. The intensity, the energy, the temporal and spatial distribution, and the repetitition rate of the emitted electron beams can be controlled within wide limits via the excitation pulses and external focusing and accelerating electromagnetic fields. The technological advantages and difficulties of ferroelectric cathodes during production and in practical operation are identified and discussed. A new design of electron guns with ferroelectric cathodes is described. Experience with a few applications of ferroelectric electron emission is reported and suggestions for further applications are made.

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