PLZT透明陶瓷的微区组分调控及梯度设计与电光性能研究

Electro-Optical Properties of PLZT Transparent Ceramics with Composition Regulating in Micro-Regions and Gradient Designing

镧掺杂锆钛酸铅(PLZT)透明陶瓷因其优异的光学透明性和电光效应,在现代光通信和高能激光技术等领域具有重要应用前景。然而PLZT透明陶瓷的电光性能对环境温度变化非常敏感,增加了其在宽温度范围电光调制器中的应用难度。本文围绕PLZT(10/65/35)透明陶瓷开展了材料铁电、介电及电光性能随温度变化的相关研究,通过对关键掺杂离子La^(3+)含量的微区调控和构建一定分布梯度,改善材料的电光性能及其温度稳定性。通过传统氧气氛热压烧结获得系列纯钙钛矿相结构的PLZT陶瓷,材料显微结构均匀致密;所有样品均呈现良好的光学透过率(52%~60%,λ=632.8 nm);随着La^(3+)含量微量增加,PLZT陶瓷的介电峰谱弛豫性增大,同时微区La^(3+)组分波动性增强的0-3复合和2-2复合PLZT陶瓷的介电温谱谱峰显著展宽且介电常数峰值提高;随温度的升高,陶瓷样品的铁电电滞回线(P-E)中最大极化值(P_(max))、剩余极化值(P_(r))和矫顽力场强(E_(c))逐渐减小;0-3复合和2-2复合PLZT(10/65/35)陶瓷的铁电极化值P max比均匀混合PLZT(10/65/35)陶瓷明显提高,且其等效二次电光系数在弥散相变温区显著增加。

Lanthanide-doped lead zirconate titanate(PLZT)transparent ceramics have significant potential for application in modern optical communication and high energy laser technology due to their exceptional optical transparency and electro-optical effects.However,the electro-optical(E-O)properties of PLZT transparent ceramics are highly sensitive to changes of ambient temperature,which presents a significant challenge in their application in E-O modulators across a wide temperature range.The objective of this study was to investigate the effects of temperature on the ferroelectric,dielectric and E-O properties of PLZT(10/65/35)transparent ceramics,and optimize the material E-O properties and their temperature stability by regulating the distribution of the key doping element La^(3+)in micro regions.A series of PLZT ceramic samples with pure perovskite structures were obtained by a conventional hot-press sintering process in oxygen atmosphere.The resulting microstructures are uniform and dense,and the optical transmittances of the samples are 52%~60%at a wavelength of 632.8 nm.The broadened dielectric peaks of PLZT ceramics indicate the relaxation characteristics of the materials,and it is promoted as La^(3+)content increasing,and enhance obviously by the enlarged La^(3+)fluctuation in micro-regions in the 0-3 and 2-2 composite PLZT ceramics with a more broadened dielectric peak and higher dielectric constant.The ferroelectric hysteresis loops(P-E)of the PLZT ceramics all exhibit a gradual decrease in maximum polarization value(P_(max)),residual polarization value(P_(r)),and coercivity field strength(E_(c))with the temperature increasing.P max values of 0-3 and 2-2 composite PLZT(10/65/35)ceramics are obviously higher than that of the well-distributed PLZT(10/65/35)ceramics,and their equivalent secondary E-O coefficients are significantly increased near the temperature of diffuse phase transition.