Relaxor ferroelectrics, which can exhibit exceptional electromechanical coupling, are some of the most important functional materials, with applications ranging from ultrasound imaging to actuators. Since their discovery, their complex nanoscale chemical and structural heterogeneity has made the origins of their electromechanical properties extremely difficult to understand. Here, we employ aberration-corrected scanning transmission electron microscopy to quantify various types of nanoscale heterogeneities and their connection to local polarization in the prototypical relaxor ferroelectric system Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃. We identify three main contributions that each depend on Ti content: chemical order, oxygen octahedral tilt and oxygen octahedral distortion. These heterogeneities are found to be spatially correlated with low-angle polar domain walls, indicating their role in disrupting long-range polarization and leading to nanoscale domain formation and the relaxor response. We further locate nanoscale regions of monoclinic-like distortion that correlate directly with Ti content and electromechanical performance. Through this approach, the connections between chemical heterogeneity, structural heterogeneity and local polarization are revealed, validating models that are needed to develop the next generation of relaxor ferroelectrics.

弛豫铁电体具有出色的机电耦合性能，是一些最重要的功能材料，其应用范围从超声成像到执行器。自发现以来，它们复杂的纳米级化学和结构异质性使其机电性质的起源变得极为难以理解。在这里，我们使用像差校正的扫描透射电子显微镜来量化各种类型的纳米级异质性及其与典型弛豫铁电体系Pb（Mg _1/3 Nb _2/3）O ₃ -PbTiO _3中的局部极化的关系。。我们确定了三个主要依赖于Ti含量的主要贡献：化学顺序，氧八面体倾斜和氧八面体变形。发现这些异质性与低角度极性畴壁在空间上相关，表明它们在破坏远程极化并导致纳米级畴形成和弛豫响应中的作用。我们进一步定位与钛含量和机电性能直接相关的单斜晶样变形的纳米级区域。通过这种方法，揭示了化学异质性，结构异质性和局部极化之间的联系，从而验证了开发下一代松弛铁电体所需的模型。