Polarization switching in ferroelectric cathodes

Abstract

A new mechanism of polarization switching and electron emission in ferroelectric cathodes is proposed. Surface flashover plasma of a ferroelectric origin was observed on a polar ferroelectric surface ͓D. Shur, G. Rosenman, and Ya. E. Krasik, Appl. Phys. Lett. 70, 574 ͑1997͔͒. Simultaneous measurements of switched charge and plasma density show that expanding surface plasma represents a dynamic switching electrode. Direct measurements of ion/electron emission currents and surface analysis implemented by different analytic tools indicate that electrons and ions from the surface plasma contribute to spontaneous polarization screening. The high energy of charged particles emitted from the surface plasma is ascribed to a high surface potential during polarization switching.

Pressure-induced switching in ferroelectrics: Phase-field modeling, electrochemistry, flexoelectric effect, and bulk vacancy dynamics

“…This has further stimulated studies of ferroelectric switching behaviors using rigid polarization (P = const) models 13,[31][32][33][34][35] and Landau-Ginzburg-Devonshire (LGD) theory based models in which polarization is defined from the minimum of corresponding free energy functional. 20,23,[36][37][38][39][40][41] However, in all these analyses, the driving force for the ferroelectric switching is the modification of electrostatic energy by applied electric field, i.e., elec f~ -PE where P is the polarization vector and E is the electric field, and mechanical response stems purely from piezoelectricity.…”

Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma

“…1, is similar to other setups for study of FPS. [1][2][3][4][5][6][7][8][9][10] The ferroelectric plasma source consists of a ferroelectric disc Operation of the FPS with probes was observed by Andor I-Star ® ICCD camera.…”

“…The principle of FPS operation is based on the ability of ferroelectric materials to build up substantial polarization charge in response to a driving pulse application. 1,2,3 The patterned structure of the front electrode induces a strong nonuniformity of the surface distribution of the polarization charge, which leads to substantial electric fields along the ceramic surface. At the edges of the patterned electrode, the electric field is sufficient for the field emission from triple junctions.…”

Ferroelectric Emission Cathodes for Low-Power Electric Propulsion

“…The non-e mitting surface of the ceramic is genera ll y covered with a solid conducting electrode, and the emitting surface is pal1ially covered by a conducting grid. FEE cathodes ha ve been driven by unipolar [5] or bipolar [6] appli ed pul ses. The postulated mechanisms for FEE include fast polarization reversa l [6] , triple point emission [7], and surface plasma extraction [8].…”

“…FEE cathodes ha ve been driven by unipolar [5] or bipolar [6] appli ed pul ses. The postulated mechanisms for FEE include fast polarization reversa l [6] , triple point emission [7], and surface plasma extraction [8]. FEE cathodes have been exami ned as cathodes for traveling wave tubes [9], gas spark switches, fl at panel displays [10] , and discharge lamps [I I] .…”