Abstract
The effects of La3+ partial substitution for Ba2+ on crystal structure and dielectric properties were investigated for modification of Ba5LaTi3Ta7O30 ceramics. When the substitution x > 0.6, the sintering temperature obviously decreased. Superstructure peaks were observed for more La3+ substitution (x ≥ 2.4). The stability of the tetragonal tungsten bronze phase was discussed with electronegativity difference and tolerance factor. Lattice parameters decreased at first, and then slightly increased; while axial ratio decreased with increasing La content. Dielectric constant slightly increased when x < 1.2, then gradually declined with the increase of La substitutions for Ba. Dielectric loss was very low except x = 2.4. Temperature coefficient of dielectric constant (at 1 MHz) was remarkably improved. The variation of dielectric properties was discussed from the change of crystal structure as well as the effects of vacancies at A-sites and superstructure.
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Acknowledgements
The present work was supported by Fujian Science Fund for Young Scholars (No.2005J012), and Fuzhou University Science Foundation (No.XJY0413, No. 2005-XY-01).
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Zheng, X.H., Zhou, X.H. Crystal structure and dielectric properties of La3+ substituted Ba5LaTi3Ta7O30 ceramics. J Mater Sci: Mater Electron 17, 987–991 (2006). https://doi.org/10.1007/s10854-006-9007-5
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DOI: https://doi.org/10.1007/s10854-006-9007-5