弛豫铁电体铌镁酸铅/钛酸铅陶瓷的内耗及其界面动力学性能

Origin of the Internal Friction Peak and Dynamics of Phase Interfaces in Relaxor Ferroelectric PMN-15PT

采用动态力学分析仪研究了弛豫铁电体铌镁酸铅/钛酸铅(PMN-15PT)陶瓷在室温附近的内耗峰随振幅、频率及升温速率变化的规律,并用界面动力学模型分析了PMN-15PT中极化微区的界面动力学特性.结果表明,PMN-15PT的内耗峰与其极化微区的界面运动有关.界面动力学模型能够描述PMN-15PT内耗峰的升温速率及其频率效应,所对应的界面为具有较小回复系数的软界面,且与其他微米级材料的硬界面有所不同.

The dynamic dissipation behaviors of boundaries of polar nanoregions（PNRs） in PMN-15PT ceramics were investigated via internal friction and modulus measurements.An internal friction peak depended strongly on the variation rate of temperature θ and applied vibrating frequency f was observed in the temperature range of relaxor ferroelectrics.The nature of the internal friction peak was suggested to be associated with the dynamic process of the motion of PNRs＇ boundaries driven by the variation of temperature and the feature of PNRs＇ boundaries could be described by the dissipation function model proposed for the phase interface dynamics of first-order phase transition.By comparison to other kinds of ceramic samples with normal sized phase interface,it was found that the interface of PNRs is a class of soft interface with small dynamic restoring coefficient and weak interaction between the interfaces and applied driven field.