Dielectric Properties of Eu-Doped CaCu_lus-plus">3Ti_lus-plus">4O_lus-plus">12 with Different Compensation Mechanisms

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• 作者：Jun-Wei Liu ; Da-Yong Lu ; Xin-Yu Yu…
• 关键词：CaCu3Ti4O12 ; Compensate doping ; Carrier localization ; Oxygen vacancy
• 刊名：Acta Metallurgica Sinica (English Letters)
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：30
• 期：2
• 页码：97-103
• 全文大小：
• 刊物主题：Metallic Materials; Spectroscopy/Spectrometry; Organometallic Chemistry; Tribology, Corrosion and Coatings; Nanotechnology; Characterization and Evaluation of Materials;
• 出版者：The Chinese Society for Metals
• ISSN：2194-1289
• 卷排序：30

文摘

To get a better understanding of the influence of rare-earth element doping, CaCu₃Ti₄O₁₂ (CCTO) samples with a partial substitution of Ca with Eu with different compensation mechanisms were designed and prepared by solid-state reaction. All the ceramics were single phase, while the dielectric constants and thermally activated energy values for dielectric relaxation in Eu-doped ceramics were both lower than those of CCTO. Ca_0.875Eu_0.1Cu₃Ti₄O₁₂ (CECT1) exhibited a slight decrease in both the permittivity and electric resistance of grain boundaries compared with CCTO, while Ca_0.85Eu_0.1Cu₃Ti₄O₁₂ (CECT2) underwent a sharp decrease in permittivity associated with an abnormally large resistance. The different dielectric behavior indicates that the dielectric properties of CCTO are sensitive to the valence states of cations and defects. The variation of permittivity is related to the localization of carriers, which, according to the XPS results, should be caused by the presence of oxygen vacancies. The formation of defect complexes between cations and oxygen vacancies leads to the increase in resistance and prevents the hopping between Cu+ and Cu2+, which is an important source of the polarization in grain boundaries.