Barium titanate is a classical ferroelectric material that exhibits a jump-like behavior in the order parameter, spontaneous polarization, near the temperature of its transition to the paraelectric phase. This serves as a textbook example of a first-order phase transition, marked by the coexistence of polar and non-polar phase regions. Despite compelling evidence of the gradual phase transformation across Curie temperature (T_c) and partial retention of ferroelectric properties above T_c, the microscopic mechanisms of the phase retention remain unclear. Current study explains temperature anomalies in the macroscopic characteristics of polycrystalline barium titanate by employing complementary macroscopic and local techniques. Our findings reveal that retention of the polar phase regions is driven by the charged defects, which act as the origin of the spatially non-uniform internal electric fields. The insights from this research offer a deeper understanding of the fundamental mechanisms governing ferroelectric behavior and open new possibilities for tailoring materials with phase coexistence for a wide range of technological applications.

中文翻译：

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多晶铁电 BaTiO3 中极性纳米区域的扩散介电行为和保留的介尺度机制


钛酸钡是一种经典的铁电材料，在阶次参数（自发极化）中表现出跳跃状行为，接近其向顺电相转变的温度。这是一阶相变的教科书式示例，其标志是极性和非极性相区域共存。尽管有令人信服的证据表明，在居里温度 （T_c） 范围内逐渐发生相变，并且在 T_c 以上部分保留了铁电特性，但相保持的微观机制仍不清楚。目前的研究通过采用互补的宏观和局部技术来解释多晶钛酸钡宏观特性中的温度异常。我们的研究结果表明，极性相区域的保留是由带电缺陷驱动的，这些缺陷是空间上不均匀的内部电场的来源。这项研究的见解提供了对控制铁电行为的基本机制的更深入理解，并为为广泛的技术应用定制具有相位共存的材料开辟了新的可能性。