RAMAN AND DIELECTRIC SPECTRA OF CaCu3Ti3.9O12 CERAMICS
RAMAN AND DIELECTRIC SPECTRA OF CaCu3Ti3.9O12 CERAMICS
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DOI：
10.1080/10584580802089023
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发表时间：
2008-06
影响因子：
0.7
通讯作者：
Kai-Hao Chen;Yong Wu;Jing Liao;Jian-Hong Liao;Jingsong Zhu
中科院分区：
文献类型：
--
作者：
Kai-Hao Chen;Yong Wu;Jing Liao;Jian-Hong Liao;Jingsong Zhu
摘要为了研究高介电CaCu3Ti4.0O12（CCTO 39）陶瓷的物理成因，采用传统的固相反应法制备了缺钛CaCu3Ti3.9O12（CCTO 39）陶瓷。拉曼光谱表明，Fg（3）模的阻尼，即O-Ti-O反伸缩运动，在CCTO 39中比在CCTO 39中更高，并且表明反伸缩运动在CCTO 39样品中可能过阻尼。介电谱表明，在150 K以上，相对介电常数ε′从CCTO的ε 105降低到CCTO 39的ε 103，在最低温度下，相对介电常数ε ′从CCTO的ε 220降低到CCTO 39的ε 140。耗散峰被抑制了10倍。它们的特征弛豫频率可能不服从阿克里先乌斯定律，而是一种试探性的关系。实验结果表明，介电弛豫与Ti离子和缺陷的相互关联运动有关。
ABSTRACT To investigate the physical origin of high dielectric CaCu3Ti4.0O12 (CCTO), we have prepared the Ti-deficiency CaCu3Ti3.9O12 (CCTO39) ceramics, using the traditional solid state reaction method. Raman spectroscopy shows the damping of Fg(3) mode, i.e. the O-Ti-O antistretching motion, is higher in CCTO39 than in CCTO and suggests that the antistretching motion may be over damped in the CCTO39 samples. The dielectric spectrum presents that, the relative dielectric constant, ε′, reduces from ∼ 105 (CCTO) to ∼ 103 (CCTO39) above 150 K, and at the lowest temperature it reduces from ∼ 220 (CCTO) to ∼ 140 (CCTO39). The dissipation peaks are 10-foldly depressed. Their characteristic relaxation frequencies may not obey the Arrhenius law but a tentative relation. All the experiments suggest that the dielectric relaxation is related to the mutually correlated motion of Ti ions and defects.