Macroscopic polarization in the nominally ergodic relaxor state of lead magnesium niobate
Macroscopic polarization in the nominally ergodic relaxor state of lead magnesium niobate
复制标题
DOI：
10.1063/5.0018243
复制
发表时间：
2020-09
影响因子：
4
通讯作者：
L. Riemer;K. Chu;Yang Li;H. Uršič;A. Bell;B. Dkhil;Dragan Damjanovic
中科院分区：
文献类型：
--
作者：
L. Riemer;K. Chu;Yang Li;H. Uršič;A. Bell;B. Dkhil;Dragan Damjanovic
研究了Pb（Mg 1/3 Nb 2/3）O3（PMN）晶体和陶瓷的宏观极性及其对外电场和温度的动态响应。动态热释电测量提供了持久的宏观极性的样品的证据。低于和高于极化样品的Burns温度的退火实验将这种极性与极性纳米实体及其动力学的存在相关联。宏观极化反转所需的直流电场强度类似于动态非线性介电常数达到最大值时的交流场的振幅。因此，上述最大值与极性纳米实体的重取向有关。结果质疑存在一个遍历状态的PMN低于伯恩斯温度。
Macroscopic polarity and its dynamic response to external electric fields and temperature in the nominally ergodic relaxor phase of pristine lead magnesium niobate crystals and ceramics, Pb(Mg1/3Nb2/3)O3 (PMN), were investigated. Dynamic pyroelectric measurements provide evidence for persistent macroscopic polarity of the samples. Annealing experiments below and above Burns temperature of polarized samples relate this polarity to the presence of polar nano-entities and their dynamics. The dc electric field strength required for macroscopic polarization reversal is similar to the amplitude of the ac field where dynamic nonlinear dielectric permittivity reaches its maximum. Consequently, the aforementioned maximum is related to the reorientation of polar nano-entities. The results question the existence of an ergodic state in PMN below Burns temperature.