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Lanthanum doped barium titanate materials with optimized properties for high capacity materials application

Boulos, Madona and Guillemet-Fritsch, Sophie and Nguyen, Manh Quan and Valdez-Nava, Zarel and Farenc, Jean and Durand, Bernard Lanthanum doped barium titanate materials with optimized properties for high capacity materials application. (2009) Silicates Industriels, 74 (1-2). 15-22. ISSN 0037-5225

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A series of lanthanum doped barium titanate, of formula Ba1-xLaxTi1-x/4O3 (0 ≤ x ≤ 0.138), were prepared and characterized. A soft chemistry technique, the coprecipitation method, was used to synthesize the powders. First, the oxalate precursors were obtained, starting from an aqueous solution containing TiCl3, BaCl2.2H2O and LaCl3.7H2O, coprecipitated with an alcoholic solution of oxalic acid. After calcination at 850°C, the oxide powders of composition Ba1-xLaxTi1-x/4O3 were obtained. The oxide powders crystallize in the cubic perovskite phase. SEM-FEG micrographs show that the powders are highly agglomerated. The size of the microcrystallites was estimated to 30 nm. Ceramics have been prepared by conventional sintering treatment (10 or 20 h at 1250°C or 1275°C). The ceramics are well densified without any abnormal grain growth. The Curie temperature (Tc) decreases linearly as the lanthanum content increases and, at the same time, an increase in the relative permittivity (εr) maximum at Tc occurs and reaches 10 000 in the most favourable case. This optimal composition is retained for possible applications.

Item Type:Article
Audience (journal):International peer-reviewed journal
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Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:14 Jun 2011 07:56

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