ABDELKEFI, Helmi; KHEMAKHEM, Hamadi; DARRIET, Jacques; SIMON, Annie

doi:10.1016/j.jallcom.2007.09.031

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ABDELKEFI, Helmi
Laboratoire des Matériaux Ferroélectriques [LMF]

KHEMAKHEM, Hamadi
Laboratoire des Matériaux Ferroélectriques [LMF]

DARRIET, Jacques
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

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Journal of Alloys and Compounds. 2008, vol. 463, n° 1-2, p. 423-427

Elsevier

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The Ba0.985Na0.015Ti0.985Nb0.015O3, Ba0.6Na0.4Ti0.6Nb0.4O3 and Ba0.3Na0.7Ti0.3Nb0.7O3 compositions of the (1 − x) BaTiO3–xNaNbO3 (BTNNx) system have been studied by X-ray diffraction and by measurements of dielectric properties. The specimens with composition BTNN (x = 0.015, 0.40 and 0.70) have been refined by the JANA program from X-ray powder diffraction data. Ceramic samples with composition (1 − x) BaTiO3 + xNaNbO3 (where x = 0.015, 0.40 and 0.70) were prepared by calcinations from appropriate mixture of BaCO3, TiO2, Na2CO3 and Nb2O5. The calcined powder was sintered at temperature range 1200–1400 °C. As the composition x increased from 0.015 (and 0.70), the ferroelectric ceramics (x = 0.015, FE) with tetragonal phase changed to the ferroelectric relaxors (RFE, x = 0.40). RFE ceramics showed a peculiar diffuse phase transition and dielectric relaxation at the low temperature (down to 180 K) due to a frustration between RFE and FE state. These ceramics present the classical ferroelectric character when 0 ≤ x < 0.075 and 0.55 < x ≤ 1 and relaxor character when 0.075 ≤ x ≤ 0.55.< Réduire

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X-ray

Dielectric

Ferroelectric

Ceramics

Relaxor behaviour

Lead-free

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X-ray diffraction study of Ba0.985Na0.015Ti0.985Nb0.015O3, Ba0.6Na0.4Ti0.6Nb0.4O3 and Ba0.3Na0.7Ti0.3Nb0.7O3 compositions

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