Giant dielectric constant response in a copper-titanate
Giant dielectric constant response in a copper-titanate
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DOI：
10.1016/s0038-1098(00)00182-4
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发表时间：
2000-01-01
影响因子：
2.1
通讯作者：
Shapiro, SM
中科院分区：
文献类型：
--
作者：
Ramirez, AP;Subramanian, MA;Shapiro, SM
我们描述了一种材料，立方CaCu 3 Ti4 O 12，它表现出大的介电响应，温度依赖性，其中还没有看到，据我们所知，在任何现有的材料。该化合物具有与10（4）[1]类似的低频介电常数，其在100-400 K的温度范围内仅微弱变化。然而，在类似于100 K的T以下，λ的值突然减少100倍。X射线衍射和热力学数据反对铁电性的解释，即局部偶极矩的集体排序。低频介电响应以及拉曼散射数据表明存在高度极化弛豫模式的特征间隙能量为28毫电子伏。(C)2000爱思唯尔科技有限公司版权所有。
We describe a material, cubic CaCu3Ti4O12, which exhibits a large dielectric response, the temperature-dependence of which has not been seen, to our knowledge, in any existing material. This compound possesses a low-frequency dielectric constant, epsilon similar to 10(4) [1], which is only weakly varying in the temperature range 100-400 K. Below T similar to 100 K, however, there is an abrupt 100-fold reduction in the value of epsilon. X-ray diffraction and thermodynamic data argue against an explanation in terms of ferroelectricity, i.e. the collective ordering of local dipole moments. Both the low-frequency dielectric response as well as Raman scattering data suggest the existence of highly polarizable relaxational modes with a characteristic gap energy of 28 meV. (C) 2000 Elsevier Science Ltd. All rights reserved.