Study of fractal dynamics in relaxor ferroelectrics

众所周知，弛豫体在很宽的温度范围内表现出很大的介电响应，但其物理起源仍然不清楚。在本研究中，我们利用宽带光散射技术来阐明弛豫体的介观尺度动力学，特别关注单晶样品中的分形与其大介电响应之间的关系。因此，我们发现大多数弛豫体都表现出自相似的准弹性光散射现象，这直接表明了单晶基质内部存在着分形（真实的空间中的自相似结构）。我们还发现，它是由极性纳米区域的集群组成的分形。我们指出，极性纳米区域团簇的分形动力学可以解释驰豫剂的介电响应。

Relaxors are well known to exhibit large dielectric response in a wide range of temperature, but its physical origin is still not clear. In this research, we used broadband light scattering technique to elucidate the meso-scale dynamics in relaxors, paying special attention on the relationship between the fractal in single crystalline samples and thier large dielectric responses. Consequently, we have found that most relaxors exhibit self-similar quasielastic light scattering phenomenon, which directlly indicate the existens of fractals (self-similar structure in real space) inside the single crystalline matrix. We also found that that it was the clusters of polar nano-regions that consists the fracal. We pointed out that the fractal dynamics of the polar nano-region clusters could account for the dielectric responses of relaxors.