Polarization Switching of and Electron Emission from Lead Lanthanum Zirconate Titanate Ceramics

Abstract

This paper focuses on understanding the influence of ma‐terial properties on the complicated ferroelectric (FE) emis‐sion process. Three different compositions in the lead lan‐thanum zirconate titanate (PLZT) system were chosen for study, based on their widely different dielectric and ferro‐electric properties: antiferroelectric (AFE) 2/95/5, “nor‐mal” ferroelectric 8/65/35, and nonferroelectric 15/65/35. Repeatable emission was obtained from the 2/95/5 compo‐sition, which could also be modulated at high frequency (200 kHz). The fast AFE ⇆ FE phase transition is respon‐sible for the FE emission properties of this material, which is supported by the relationship between the switching cur‐rent and the emission current. Comparatively, FE emission from the 8/65/35 composition degraded rapidly, which was attributed to decreases in the remanent polarization. No emission signal was detected from the 15/65/35 composi‐tion, because no switching activity occurs, which can be interpreted as additional evidence that electron emission from the previously mentioned two compositions was in‐deed a FE emission process.