The permittivity and the conductivity of Ba-hollandite Ba_1.16M_2.32Ti_5.68O₁₆ (M = Al, Ga) observed by dielectric spectroscopy

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• 作者：V. Aubin-Chevaldonnet ; J.C. Badot ; D. Caurant
• 关键词：Hollandite ; Dielectric spectroscopy ; Barium ion conductivity ; Permittivity
• 刊名：Solid State Ionics
• 出版年：2007
• 期刊代码：96_01672738
• 类别：ch
• 出版时间：31 July 2007
• 卷：178
• 期：21-22
• 页码：1274-1281
• 文件大小：985 K

摘要

Broadband dielectric and resistivity spectra of sintered Ba_1.16Al_2.32Ti_5.68O₁₆ and Ba_1.16Ga_2.32Ti_5.68O₁₆ hollandites were recorded in a frequency range 40–1.1 × 10⁸ Hz at temperatures varying between 320 and 440 K. All the data are presented in the form of complex permittivity and resistivity diagrams in order to obtain respectively the lattice permittivity and the thermal behaviour of the ionic conductivity with respect to the nature and the dielectric polarizabilities of the ionic species in hollandites. A dielectric relaxation was observed depending on the hollandite type and the temperature. A tentative assignment of this relaxation to physical mechanisms is proposed: thermal activated hopping and on-site large amplitude fluctuations of Ba²⁺ ions.