Showing papers on "Ferroelectric ceramics published in 1975"
TL;DR: The highvoltage photo-emf seen in poled ferroelectric ceramics is explained as the result of light-induced carriers screening an internal field within the bulk of individual grains as discussed by the authors.
Abstract: The high-voltage photo-emf seen in poled ferroelectric ceramics is explained as the result of light-induced carriers screening an internal field within the bulk of individual grains. The internal field itself is explained as the result of the shielding by equilibrium carriers of the potential produced by the spontaneous polarization. Less-than-band-gap emf’s are produced across individual grains; these emf’s add in ceramics to produce the high-voltage photo-emf. A model yields the polarity and magnitude of the photo-emf, the dependence on temperature, remanent and spontaneous polarization, dielectric constant and grain size. The calculated and experimental results are in general agreement.
124 citations
TL;DR: In this paper, impact-loading techniques are used to investigate the electromechanical response of poled specimens of a ferroelectric ceramic, PZT 95/5, to long−duration shock pulses.
Abstract: Reproducible and predictable electrical pulses with peak powers of a few hundred kilowatts lasting for a few microseconds can be obtained from shock−wave compressed ferroelectrics. In this work, impact−loading techniques are used to investigate the electromechanical response of poled specimens of a ferroelectric ceramic, PZT 95/5, to long−duration shock pulses. The experiments are conducted in the normal mode in which the shock propagation vector is perpendicular to the remanent polarization. Current histories are obtained as a function of load resistance for a fixed shock amplitude of 1.4 GPa, and few additional experiments investigate the stress dependence of the electrical response. A simple, though specific, model is developed that gives good agreement with observed results. The extension of this model to other materials and shock−loading conditions is discussed.
111 citations
TL;DR: In this paper, the effects of the ferroelectric−to−paraelectric transformation and other factors are discussed for shock-loaded PZT materials, and it is shown that the dielectric breakdown of PZTs can be predicted from ambient and quasistatic−loading data using the concept of a critical particle energy.
Abstract: Recent investigations of dielectric breakdown of a poled ferroelectric ceramic suggest that the same mechanisms are acitve in shock−loading and ambient−condition experiments. Further work described here supported this view for PZT 65/35. Breakdown in shock−loaded specimens can be predicted from ambient and quasistatic−loading data using the concept of a critical particle energy. The effects of the ferroelectric−to−paraelectric transformation and other factors are discussed for shock−loaded PZT materials.
25 citations
TL;DR: In this article, the authors show that PSZT 70/30•6 exhibits a phase transformation near 0.3 GPa, which is similar to that of other ferroelectric ceramics.
Abstract: Projectile impact experiments were conducted on specimens of PSZT 70/30‐6. The shock‐wave‐induced depolarization of this material has an equilibration time of ?0.2 μsec which is similar to that of other ferroelectric ceramics. However, PSZT 70/30‐6 does not revert rapidly to a poled state upon unloading. Thus, a nearly constant voltage is produced in our axial‐mode experiments even though shock and release waves reverberate within the specimens. This interesting response of PSZT 70/30‐6 is likely caused by a phase transformation near 0.3 GPa.
15 citations
TL;DR: In this article, the optical transmittance and crystal-lattice distortion in hot-pressed La-doped Pb zirconate-titanate (PLZT) ferroelectric ceramics at the FE-AFE morphotropic phase boundary were studied.
Abstract: Optical transmittance and crystal-lattice distortion and their relation were studied in hot-pressed La-doped Pb zirconate-titanate (PLZT) ferroelectric ceramics at the ferroelectric-antiferroelectric morphotropic phase boundary. In the thermally annealed condition, the crystal system of PLZT at the FE-AFE morphotropic phase boundary was pseudotetragonal and similar to the antiferroelectric phase (AFEβ) appearing in Pb(Zr, Ti)O3 and (Pb, Sr)ZrO3. Optical transmittance and crystal-lattice distortion change monotonically with respect to the Zr/Ti ratio, and the optical transmittance increases approximately linearly with decreasing lattice distortion. In view of these relations and the temperature dependence of the optical transmittance, it is suggested that light scattering in PLZT ceramics is caused mainly by the variation in refractive index encountered as the light travels from one domain or grain into another.
10 citations