Diverging Relaxation Times of Domain Wall Motion Indicating Glassy Dynamics in Ferroelastics

Single crystals of PbZrO3 and LaAlO3 have been studied by Dynamic Mechanical Analysis measurements in the low frequency range f = 0.02-50 Hz. The complex Young's modulus exhibits a quite rich behavior and depends strongly on the direction of the applied dynamic force. The low frequency elastic response in the [110]c-direction is dominated by domain wall motion, leading to a superelastic softening effect below Tc. With decreasing temperature this superelastic softening gradually disappears, due to an increasing relaxation time τDW of domain wall motion. For PbZrO3, τDW seems to diverge at a finite temperature TVF, indicating glassy behavior of domain freezing.

本研究针对锆酸铅（PbZrO3）与铝酸镧（LaAlO3）单晶体，在0.02~50 Hz的低频区间内开展了动态力学分析（Dynamic Mechanical Analysis）测试。复杨氏模量展现出极为丰富的变化特性，且与所施加动态力的方向密切相关。在[110]c晶向的低频弹性响应以畴壁运动为主要机制，会在低于Tc温度时产生超弹性软化效应。随着温度降低，畴壁运动的弛豫时间τDW逐渐增大，该超弹性软化效应也随之逐步消失。对于锆酸铅而言，τDW似乎会在有限温度TVF处发生发散，表明体系存在畴冻结的玻璃态行为。