摘要
在ＫＤＰ、ＴＧＳ中，Ｔｃ附近分别观测到两个内耗（Ｑ－１）和介电损耗（Ｄ）峰，在ＬＮＰＰ中观测到相应的两个内耗峰，Ｐ１峰起源于二级相变的涨落效应，而Ｐ２与畴有关．考虑到Ｔｃ附近序参量以及由之而引起的畴界密度和畴界运动的粘滞系数随温度的显著变化，计算了与畴界运动有关的内耗和介电损耗，并和实验结果进行了比较．在弛豫铁电体ＰＭＮ—ＰＴ中，Ｔｃ以下也观测到相应于Ｐ２峰的内耗和介电损耗峰，考虑到畴界运动和其它一些因素。
Two internal friction (Q-1') and dielectric (D) peaks (P1, P2) for KDP, TGS and two Q-1 peaks for LNPP were investigated. P1 is attributed to fluctuations near a 2nd-order phase transition and P2 is related to domain walls (DWs). Taken into account the temperature dependence of the density and the viscosity of DWs as well as the order parameter and the interaction between DWs,Q-1 and D due to the viscous motion of DWs were calculated and compared with the experimental data in the kHz range. Q-1 and D peaks were also measured in the relaxor ferroelectric PMN-PT for various frequencies. A qualitative analysis based on DWs and other factors for the peaks is suggested.
出处
《材料研究学报》
EI
CAS
CSCD
1994年第1期2-10,共9页
Chinese Journal of Materials Research
关键词
内耗
介电损耗
铁电体
相变
domain wall
internal friction
dielectric loss
ferroelectrics
phase transition (PT)
