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采用固相烧结法合成了单相巨介电常数氧化物CaCu3Ti4O12（CCTO）.用阻抗分析仪分析了10—420 K温度范围内的介电频谱和阻抗谱特性，并结合ZVIEW软件进行了模拟.结果表明：温度高于室温时，频谱出现两个明显的弛豫台阶，低频弛豫介电常数随温度升高而显著增大，表现出热离子极化特点；温度低于室温时，频谱表现出类德拜弛豫，且高、低平台介电常数值基本不随温度变化，表现出界面极化特点和较好的温度稳定性.频谱中依次出现的介电弛豫对应于阻抗谱中
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关键词:
- CaCu3Ti4O12 /
- 介电频谱 /
- 阻抗谱 /
- Cole-Cole半圆弧
Pure colossal dielectric constant oxide CaCu3Ti4O12 (CCTO) compound was prepared by traditional ceramic processing. Dielectric dispersion and complex impedances spectra were investigated using a impedance analyzer within a temperature range of 10—420 K. The data were simulated by “ZVIEW” software. The result indicates that there are two obvious relaxations in the dielectric dispersion spectra when the temperature is higher than room temperature and the dielectric constant increases remarkably with increasing temperatures at a low frequency, which indicates a thermal ionic polarization. However, the frequency spectra becomes similar to Debye-type relaxation when the temperature is lower than room temperature and the low-and high-frequency relaxation step almost keeps unchanged with temperature, which reveals a feature of interface polarization and considerable temperature stability for CCTO. The relaxation revealed in the frequency spectra corresponds to the three different semicircles revealed by the impedance spectra, which indicated there are three inhomogeneous regions or polarization processes in CCTO ceramics and the colossal dielectric constant mainly comes from the extrinsic polarization of these inhomogenities. The activation energies are found to be respectively 0.05 eV, 0.58 eV and 0.49eV for the three different polarization processes by simulating the impedance semicircles using an equivalent circuit.-
Keywords:
- CaCu3Ti4O12ceramic /
- dielectric frequency spectra /
- impedance spectra /
- Cole-Cole semicircles
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[9] ［9］Lunkenheimer P, Fichtl R, Ebbinghaus S G, Loidl A 2004 Phys. Rev. B 70 172102
[10] ］Sun D L, Wu A Y, Yin S T 2008 J. Am. Ceram. Soc .91 169
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[15] ］Adams T B, Sinclair D C, West A R 2006 J. Am. Ceram. Soc. 89 3129
[16] ］Shao S F, Zheng P, Zhang J L, Niu K X, Wang C L, Zhong W L 2006 Acta Phys. Sin. 58 523 (in Chinese) ［邵守福、郑鹏、张家良、钮效鹍、王春雷、钟维烈 2006 55 6661］
[17] ］He L, Neaton J B, Morrel H，Vanderbilt D 2002 Phys. Rev. B 65 21411
[18] ］Ni L, Chen X M 2007 Appl. Phys. Lett . 91 122905
[19] ］Yin G L, Li J Y, Li S T 2009 Acta Phys. Sin. 58 523 (in Chinese) ［尹桂来、李建英、李盛涛 2009 58 4219］
[20] ］Krzysztof S, Wolfgang S, Gustav B, Rainer W 2006 Nat. Mater. 5 312
[21] ］Li S T, Cheng P F, Zhao L, Li J Y 2009 Acta Phys. Sin. 58 523 (in Chinese) ［李盛涛、成鹏飞、赵雷、李建英 2009 58 523］
[22] ］Yang F X, Zhang D M, Deng Z W 2008 Acta Phys. Sin. 57 3840 (in Chinese) ［杨凤霞、张端明、邓宗伟等 2008 57 3840］
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[1] ［1］ Subramanian M A, Li D, Duan N, Reisner B A, Sleight A W 2000 J. Solid State Chem. 151 323
[2] ［2］Ramirez A P, Subramanian, Gardel M 2000 Solid State Commun. 115 217
[3] ［3］Homes C C, Vogt T, Shapiro S M, Wakimoto S, Ramirez A P 2001 Science 293 673
[4] ［4］Zhang J L, Zheng P, Wang C L, Zhao M L 2005 Appl. Phys. Lett. 87 142901
[5] ［5］Shao S F, Zhang J L, Zheng P, Zhong W L, Wang C L 2006 J. Appl. Phys. 99 084106
[6] ［6］Cao G H, Feng L X, Wang, C 2007 J. Phys. D: Appl. Phys. 40 2889
[7] ［7］Sinclair D C, Adams T A, Morrison F D, West A R 2002 Appl. Phys. Lett. 80 2153
[8] ［8］Adams T B, Sinclair D C, West A R 2002 Ade. Matter.18 1321
[9] ［9］Lunkenheimer P, Fichtl R, Ebbinghaus S G, Loidl A 2004 Phys. Rev. B 70 172102
[10] ］Sun D L, Wu A Y, Yin S T 2008 J. Am. Ceram. Soc .91 169
[11] ］Chung S Y, Kim I D, Kang S J L 2004 Nat. Mater. 3 774
[12] ］Adams T B, Sinclair D C, West A R 2006 Phys. Rev. B 73 094124
[13] ］Li J, Cho K, Wu N, Ignatiev A 2004 IEEE Trans. Dielectr. Elect. Insul. 11 534
[14] ］Zang G Z, Zhang J L, Zheng P, Wang J F, Wang C L 2005 J. Phys. D: Appl. Phys. 38 1824
[15] ］Adams T B, Sinclair D C, West A R 2006 J. Am. Ceram. Soc. 89 3129
[16] ］Shao S F, Zheng P, Zhang J L, Niu K X, Wang C L, Zhong W L 2006 Acta Phys. Sin. 58 523 (in Chinese) ［邵守福、郑鹏、张家良、钮效鹍、王春雷、钟维烈 2006 55 6661］
[17] ］He L, Neaton J B, Morrel H，Vanderbilt D 2002 Phys. Rev. B 65 21411
[18] ］Ni L, Chen X M 2007 Appl. Phys. Lett . 91 122905
[19] ］Yin G L, Li J Y, Li S T 2009 Acta Phys. Sin. 58 523 (in Chinese) ［尹桂来、李建英、李盛涛 2009 58 4219］
[20] ］Krzysztof S, Wolfgang S, Gustav B, Rainer W 2006 Nat. Mater. 5 312
[21] ］Li S T, Cheng P F, Zhao L, Li J Y 2009 Acta Phys. Sin. 58 523 (in Chinese) ［李盛涛、成鹏飞、赵雷、李建英 2009 58 523］
[22] ］Yang F X, Zhang D M, Deng Z W 2008 Acta Phys. Sin. 57 3840 (in Chinese) ［杨凤霞、张端明、邓宗伟等 2008 57 3840］
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