铁电/反铁电相界附近(Pb,La)(Zr,Sn,Ti)O3陶瓷的相结构及相变行为研究

Investigations on the phase structures and phase transition behaviors of dielectric materials are of great significance for the analysis of its properties and the design of functional materials. (Pb,La)(Zr,Sn,Ti)O3 (PLZST)ceramics is a typical ferroelectric(FE)/antiferroelectric(AFE) material. Some phase transitions and pyroelectric responses, which are sensitive to composition and external fields, have just been reported in PLZST with composition near FE/AFE phase boundary. But the physical mechanism is still unknown. In this project, the dielectric, ferroelectric, and pyroelectric properties as well as the microstructures of PLZST ceramics with different phase structures under variable external fields were planned to be investigated further. Its phase diagram near the FE/AFE phase boundary will be established accordingly. The influence of composition and external fields on the phase boundary, the coexistence area of FE and AFE phases, and the pyroelectric responses will be studied. The dynamic hysteresis scaling behaviors accompanying with the FE/AFE phase transitions under different temperature and electric fields will be studied systematically. The phase states and domain structures will be observed by in-situ measurements. The dynamic processes of phase transitions and the polarization switching behaviors will be understood furtherly, which might be albe to uncover the origins of the excellent pyroelectric properties. Some theoretical basis for the thorough understanding of phase transition effects and mechanisms in ferroelectric materials can be summarized through this study. The results of this project are also meaningful for the design and application of FE/AFE materials.

铁电材料相结构及相变行为的研究对其物理性质分析和功能材料设计具有重要意义。研究发现，典型的铁电/反铁电材料- - (Pb,La)(Zr,Sn,Ti)O3(PLZST)陶瓷在铁电/反铁电相界附近存在对组成和外场很敏感的相变行为和热释电性能，但其内在机制尚不明确。本项目拟在前期工作的基础上，进一步研究不同相结构的PLZST陶瓷在外场作用下的介电、铁电和热释电性能，结合结构分析确定其铁电/反铁电相界附近的相图，阐明组成和外场对铁电/反铁电相界、两相共存区域、相变效应的影响规律；通过系统研究温度和电场作用下铁电/反铁电相变的动态电滞回线标度行为，结合原位测试分析场致相变中的微观结构变化，深入剖析相变的动态过程及其中的极化翻转机制，揭示优异热释电性能的起源。本项目的研究结果将为深入认识铁电材料的相变效应及微观机制提供理论依据，并为铁电/反铁电材料的设计提供技术指导，具有重要的科学意义和应用价值。

铁电材料相结构及相变行为的研究对其物理性质分析和功能材料设计具有重要意义。本项目以典型的铁电/反铁电材料——(Pb,La)(Zr,Sn,Ti)O3(PLZST)陶瓷为研究对象，深入研究了其在铁电/反铁电相界附近的相变行为和热释电性能。通过研究不同相结构的PLZST陶瓷在外场作用下的介电、铁电和热释电性能，结合结构分析确定了其铁电/反铁电相界附近的相图，阐明了组成和外场对铁电/反铁电相界、两相共存区域、相变效应的影响规律；研究了温度和电场作用下铁电/反铁电相变的动态电滞回线标度行为，深入剖析了相变的动态过程及其中的极化翻转机制；研究了不同陶瓷的热释电性能，分析并揭示了其热释电响应机制。本项目的研究结果有利于加深对铁电材料相变效应的认识，并可为铁电/反铁电材料的设计提供技术指导。