弛豫铁电单晶微观结构与宏观性能的调控及其关联机制一直是凝聚态物理和材料学科领域的研究热点。本项目以Mn掺杂弛豫铁电单晶为对象，拟采用同步辐射、中子散射等手段开展多尺度极性结构及“缺陷偶极-极性纳米微区”和“缺陷偶极-相结构”跨尺度协同效应的研究。研究内容主要包括:1)实验观察多尺度极性结构特征；2)明确多尺度极性结构的外物理场演变规律；3)发展多尺度极性结构与性能调控方法；4)揭示“缺陷偶极-极性纳米微区”和“缺陷偶极-相结构”跨尺度协同效应及机理。项目开展以实验探索为重点，以构筑“后处理工艺-多尺度极性结构组态-宏观性能增益”的物理图像为主线，结合热力学和相场模拟，对多尺度极性结构的调控及其协同衍生的新奇物理效应进行深入研究。该项目研究不仅可以拓展复杂钙钛矿氧化物多尺度不均匀性结构和跨尺度协同效应的物理内涵，也为发展弛豫铁电单晶性能优化的后处理工艺以及电子器件应用奠定物理基础。

The manipulation of micro-structures, macro-properties and their correlation mechanism of relaxor ferroelectric single crystals has been a hot topic in the field of condense matter and material science. The present proposal is intended to investigate the multi-scale polar structures of Mn-doped PMN-PT and PIN-PMN-PT, i.e., defect dipole pair, polar nano region (PNR), domain structure and phase structure by synchrotron radiation, high resolution transmission electron microscope, neutron diffuse scattering, etc., and the cross-scale synergistic effects between defect dipole pair-PNR, defect dipole pair-phase structure. Four major issues will be addressed, including to: 1) experimentally observe the characteristics of multi-scale polar structures; 2) clarify evolution law of multi-scale polar structures in response to external physical fields; 3) develop methods for manipulation of multi-scale polar structures and properties; 4) reveal the underlying mechanism of cross-scale synergistic effect and the interaction of defect dipole pair-PNR, defect dipole pair-phase structure. This proposal will be mainly carried out in experiments, while simultaneously performed by some thermodynamic calculations and field phase modeling, in order to establish the physical link of “post-treatment process, configuration of multi-scale polar structure and macroscopic property”, and comprehensively study the manipulation of multi-scale polar structures and their interaction induced emergent phenomenon. This research and the promising results will not only deepen the connotation and extend the denotation of multi-scale polar heterogeneity of complex perovskites, but also provide physical basis to develop post-treatment process for properties optimization of relaxor ferroelectric single crystals and the related electronic device applications.