Colossal permittivity in titanium dioxide ceramics modified by tantalum and trivalent elements

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• 作者：Zhenwei Li^a ; Jiagang Wu^a ; ^{msewujg@scu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; ^{wujiagang0208@163.com" class="auth_mail" title="E-mail the corresponding author} ; Dingquan Xiao^a ; Jianguo Zhu^a ; Wenjuan Wu^b
• 关键词：TiO2 ceramic ; Tantalum and trivalent elements ; Colossal permittivity
• 刊名：Acta Materialia
• 出版年：2016
• 出版时间：15 January 2016
• 年：2016
• 卷：103
• 期：Complete
• 页码：243-251
• 全文大小：5439 K

文摘

Colossal permittivity (CP) materials continue to attract significant interest for their applications in high-performance capacitors and scaling advances in electronic devices. However, the unbalanced developments of their dielectric constants, dielectric losses, and stabilities still hinder practical applications. In this study, we attained a colossal permittivity (ε_r = 10⁴∼10⁵, 1 kHz) in a series of new titanium dioxide (i.e., (A_0.5Ta_0.5)_xTi_1−xO₂, where A = Al, Sm, Bi, Fe, In, Dy, Ga, Gd, Yb, or Sc) ceramics containing Ta and trivalent elements that is comparable or superior to the previously reported results in In and Nb co-doped ceramics. In addition, a low dielectric loss (tan δ∼5.4%, 1 kHz) was achieved in the ceramics by tailoring the types of trivalent elements used; such a ceramic also shows relatively good dielectric properties with regard to frequency (10²∼10⁶ Hz) and temperature (−150–200 °C) stabilities. The formation of defect-dipole clusters (e.g., ${\text{Al}}^{3+}{\mathrm{V}}_{\mathrm{O}}^{··}{\text{Ti}}^{3+}$ and Ta⁵⁺Ti³⁺A_Ti${\text{Ta}}^{5+}{\text{Ti}}^{3+}{\mathrm{A}}_{\text{Ti}}$ (A = Ti³⁺/Al³⁺/Ti⁴⁺)) induced by Ta and trivalent elements should be responsible for the observed enhancements in dielectric properties. We believe that TiO₂-based ceramics are one of the most promising candidates in the field of electronic and energy-storage devices.