Effects of Cu stoichiometry on the micro structures, barrier-layer structures, electrical conduction, dielectric responses, and stability of CaCu3Ti4O12

被引：204

作者：

Fang, Tsang-Tse

Mei, Li-Then

Ho, Hei-Fong

机构：

[1] Natl Cheng Kung Univ, Dept Mat Sci & Engn, Tainan 70101, Taiwan

[2] Chang Jung Christian Univ, Dept Business Adm, Tainan 711, Taiwan

来源：

ACTA MATERIALIA | 2006年 / 54卷 / 10期

关键词：

electroceramics; dielectric; defects; electrical properties; microstructure;

D O I：

10.1016/j.actamat.2006.02.037

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The presence of Cu3+ ions in CaCu3Ti4O12 (CCTO) has been determined using X-ray photoelectron spectroscopy and the Cu deficiency of CCTO confirmed. Electron hopping between Cu2+ and Cu3+ is proposed as the origin of the semiconducting nature of CCTO. A new model of CCTO with Cu deficiency being fundamental for the development of a barrier-layer structure is proposed. The enhancement of the densification rate, the occurrence of discontinuous grain growth, and the increase of grain boundary resistivity are found to be related to the presence of Cu ions at grain boundaries. For samples of CaCu2.9Ti4O12, the lower dielectric constant can be attributed to the smaller grain boundary areas and the difficulty in the development or domains inside the fine grains. The dielectric responses of CaCu(2.9)Tri(4)O(12) and CaCu3.1Ti4O12 can also be described using a brick-layer model. Finally, CCTO is found to be unstable and gradually decomposes. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

引用

页码：2867 / 2875

页数：9

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