A Study Of Anisotropy Of Plzt Transparent Electrically Induced Light Scattering Ceramics Prepared By Hot-press Sintering Method

The lanthanum modified lead zirconate titanate (PLZT) ceramics is a function material with excellent intercoupling properties between electricity, magnetism, light, force and heat.Especially it occupies both high transmittance (>70%) and unique electro-optic effects which include the excellent electrically controlled birefrigent effect and the unique electrically induced light scattering effect. With the development of modern laser technology, people have higher demand of light shielding, light attenuation etc. Without using the polarizer, the optical element based on PLZT electric-induced light scattering effect is expected to be applied in high-speed optical modulator, to meet the requirements of the modern laser technology application.But the PLZT ceramics' electrically induced light scattering behavior is greatly influenced by the composition, hot-press and inner stress, etc. Beginning with the compositions, we studied the physical anisotropy and the annealing effect of PLZT ceramics systematically by hot-press sintering and annealing treatment.A series of PLZT (X/70/30, X=7.45, 7.51, 7.57, 7.63) transparent ceramics were prepared by the hot-press sintering techniques to study their anisotropy in different direction. We studied their physical properties of PLZT ceramics systematically. Lanthanum elements effectively promoted grain growth and the increasing transmittance; PLZT ceramics exhibited more serious structure distortion with small tetragonality and small cell volume in parallel direction.Moreover, the lager resistance resulted in the smaller mean grain size in the process of sintering in parallel direction. PLZT ceramics shown more stable and excellent electrically induced light scattering effect though smaller transmittance in parallel direction.PLZT (X/70/30, X=7.45, 7.54, 7.63) transparent ceramics with dense and uniform microstructures were prepared to study their annealing effects based on the study of anisotropy.With the annealing treatment, the remnant polarization (Pr) and coercive electric field (Ec) of PLZT ceramics decreased pronouncedly. Especially, for PLZT (7.63/70/30) ceramic, the double slim hysteresis loops with anti-ferroelectric phase occurred. The annealing treatment observably decreased the electrically induced strain. Due to the optical and electro-optic sensitivities of PLZT ceramics to the annealing treatment, annealing treatment is defined into rapid and slow annealing treatment, respectively, based on the cooling rate. The transmittances of PLZT ceramics were enhanced by the annealing treatment, especially slow annealing treatment. Moreover, the electrically induced light scattering effect was improved by the annealing treatment, and even the PLZT (7.63/70/30) ceramic shown the different electrically induced light scattering behavior, that is, the transmittance reached its maximum and held the maximum and perfect symmetry in a wide electric field.