钛酸钡中极化团簇的特征弛豫时间随温度的变化规律

Temperature dependence of relaxation time for polarization clusters in BaTiO_3 near T_C

BaTiO3中存在极化团簇已经被大量实验所证明,并且极化团簇的空间、时间信息以及随温度的演化信息对介电性质有着重要影响。因此探测BaTiO3中极化团簇的相关信息对于理解其功能和揭示相变机理具有重要意义。本实验利用光子相关谱方法,在精确温控的条件下,观测到BaTiO3中300nm周期长程极化团簇微秒量级的特征弛豫时间τc,并揭示了该时间在TC附近4K温度范围内变化的细节特征。实验表明光子关联谱是研究铁电动力学的有效方法。

A number of experiments have proved that polarization clusters exists in BaTiO3 and excellent properties of BaTiO3 are related to a great extent with spatiotemporal information of polarzition clusters. The measurement of temporal state is essential to discuss the characteristics of the polarization clusters and to recognize the nature of the ferroelectric phase transition. In our experiment, the 300 nm long range polarization clusters in BaTiO3 were found to be dynamic with characteristic relaxation time （re） of several microseconds by Photon Correlation Spectroscopy （PCS）. The evolution details of the relaxation time were also revealed clearly in the vicinity of Tc,. It has proved that PCS is an effective method for the probing of dynamic process among ferroelectrics.