Effect of La substitution on Electrical Properties of Highly Oriented Bi4Ti3O12 Films Prepared by Metalorganic Chemical Vapor Deposition
Effect of La substitution on Electrical Properties of Highly Oriented Bi4Ti3O12 Films Prepared by Metalorganic Chemical Vapor Deposition
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DOI：
10.1143/jjap.42.166
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发表时间：
2003-01
影响因子：
1.5
通讯作者：
T. Sakai;Takayuki Watanabe;H. Funakubo;K. Saito;M. Osada
中科院分区：
文献类型：
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作者：
T. Sakai;Takayuki Watanabe;H. Funakubo;K. Saito;M. Osada
采用外延生长的Bi4Ti3O12 （BIT）薄膜和具有(001)-、(118)-和（104）（014）取向的高取向（Bi3.25La0.75）Ti3O12 [BLT]薄膜研究了La取代对Bi4Ti3O12电学性能的影响。通过对不同取向薄膜的漏电流密度进行表征，发现La取代降低了a-b平面上的漏电流密度。根据(001)-取向和（118）取向薄膜的P-E迟滞特性，BLT薄膜沿C轴和a轴的自发极化（Ps）分别为3.5和38µC/cm2。它们比BIT膜小，分别为4.0和50µC/cm2。基于La优先取代伪钙钛矿层中Bi位的事实，广泛报道的多晶（Bi3.25La0.75）Ti3O12薄膜的大残余极化与伪钙钛矿层中缺陷配合物数量的减少有关，这些缺陷配合物可能抑制了畴运动。
The effect of La substitution on the electrical properties of Bi4Ti3O12 was investigated by using epitaxially grown Bi4Ti3O12 (BIT) films and highly oriented (Bi3.25La0.75)Ti3O12 [BLT] films with (001)-, (118)- and (104)(014)-orientations. By characterizing the leakage current density for films with different orientations, it was found that the leakage current density along the a–b plane was decreased by La substitution. The spontaneous polarization (Ps) of the BLT film evaluated from the P–E hysteresis properties of the (001)- and (118)-oriented films was 3.5 and 38 µC/cm2 along the c-axis and the a-axis, respectively. They were smaller than those of the BIT films: 4.0 and 50 µC/cm2. Based on the fact that La preferentially substitutes for the Bi site in the pseudoperovskite layer, the large remanent polarization widely reported for polycrystalline (Bi3.25La0.75)Ti3O12 films is related to the reduction of the number of defect complexes in the pseudoperovskite layer that possibly pin the domain motion.