Quantitative High‐Dynamic‐Range Electron Diffraction of Polar Nanodomains in Pb2ScTaO6

Highly B‐site ordered Pb2ScTaO6 crystals are studied as a function of temperature via dielectric spectroscopy and in situ high‐dynamic‐range electron diffraction. The degree of ordering is examined on the local and macroscopic scale and is determined to be 76%. Novel analysis of the electron diffraction patterns provides structural information with two types of antiferroelectric displacements determined to be present in the polar structure. It is then found that a low‐temperature transition occurs on cooling at ≈210 K that is not present on heating. This phenomenon is discussed in terms of the freezing of dynamic polar nanodomains where a high density of domain walls creates a metastable state. Highly ordered Pb2ScTaO6 (a relaxor‐like material containing dynamic polar nanodomains at room temperature) is studied using dielectric spectroscopy, X‐ray diffraction, and in situ transmission electron microscopy. Novel intensity analysis of high‐dynamic‐range electron diffraction patterns is used to determine the picometer‐scale structural fluctuations that form a metastable state on cooling.