摘要
在制备 ０．９３ＰＭＮ－０．０７ＰＴ（ＰＭＮＴ）陶瓷时，让 ＭｇＯ过剩使Ｎ（Ｍｇ）：Ｎ（Ｎｂ）（原子比）为１：１，它与ＰＭＮ的极性微区［Ｐｂ２ＭｇＮｂ］中Ｍｇ和Ｎｂ的原于比相同．测试结果表明：与以往的ＰＭＮ－ＰＴ材料（ＰＴ的原子百分数小于 ３５％）的情况不同，在ＸＲＤ图中可观测到的铁电四方相；代表极性的 Ｎｂ－Ｏ－Ｎｂ的键振动，在Ｒａｍａｎ谱中强至可以与低温时ＰＭＮ中存在长程相关的Ｎｂ－Ｏ－Ｎｂ键的振动相比较，这说明ＰＭＮＴ中的长程相关性增大．由于高铅缺位的钉扎、自由场的存在等的影响，在介电常数峰温的低温侧存在另一准弛豫铁电－准铁电性转变（ｑＲＦＥ－ｑｎＦＥ： ｔｒａｎｓｉｔｉｏｎ）．
The 0. 93PMN-0. 07FF (PMNT) ceramic with high lead vacancies and 1:1 composition of Mg and Nb was prepared by wet chemical method. X-ray diffraction (XRD), Raman scattering technique, dielectric tempera-ture dependence measurements were used to characterize the ferroelectric properties of PMNT. It has been revealed that, a tetragonal phase was detected within the resolution of XRD, the polar vibration bond Nb - O - Nb is as strong as that in PMN at low temperature. It can be concluded that the long-range correlation of PMNT increases, a transition from quasi normal ferroelectric to quasi relaxor occurred near and below Tm' during heating due to the high lead vacancies.
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2001年第1期32-34,共3页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
广东省自然科学基金资助项目(A040105)
广州市科委重点资助项目(97-J-01-01)
