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

Abdelkefi, Helmi; Khemakhem, H.; Simon, A.; Darriet, Jacques

doi:10.1016/j.jallcom.2007.09.031

Cited by 15 publications

(7 citation statements)

References 9 publications

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“…On the other hand, (Ba x Na 1− x )(Ti x Nb 1− x )O 3 -BTNN compounds can present conventional or relaxor ferroelectric behaviors depending on the x amount in the solid solution [34,35,36]. Regarding the crystalline structure, BTNN compounds present a perovskite tetragonal symmetry for x < 0.30, a pseudo cubic symmetry for intermediate x values (0.30 ≤ x ≤ 0.70) and, with x increasing (0.70 ≤ x ≤ 0.88), the tetragonal symmetry emerges once again [14,37,38].…”

Section: Introductionmentioning

confidence: 99%

“…For higher x values, T m increases with x increasing. Moreover, an elevated dielectric constant is observed for the majority of the compounds, which is highest (ε′ max = 9500) for x = 0.90 [14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41]. Considering all these aspects, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Rather, the BTNN system relies on both very long calcining times (up to 15 h) and elevated sintering temperatures (reaching 1450 °C) [31,32,33,34,35,36,37]. This enhances the volatilization of the precursor oxides, making densification difficult and increasing the time needed for ceramic processing.…”

Section: Introductionmentioning

confidence: 99%

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Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

et al. 2016

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Lead free piezoelectric materials are being intensively investigated in order to substitute lead based ones, commonly used in many different applications. Among the most promising lead-free materials are those with modified NaNbO3, such as (K, Na)NbO3 (KNN) and (Ba, Na)(Ti, Nb)O3 (BTNN) families. From a ceramic processing point of view, high density single phase KNN and BTNN ceramics are very difficult to sinter due to the volatility of the alkaline elements, the narrow sintering temperature range and the anomalous grain growth. In this work, Spark Plasma Sintering (SPS) and high-energy ball milling (HEBM), following heat treatments (calcining and sintering), in oxidative (O2) atmosphere have been used to prepare single phase highly densified KNN (“pure” and Cu2+ or Li1+ doped), with theoretical densities ρth > 97% and BTNN ceramics (ρth ~ 90%), respectively. Using BTTN ceramics with a P4mm perovskite-like structure, we showed that by increasing the NaNbO3 content, the ferroelectric properties change from having a relaxor effect to an almost “normal” ferroelectric character, while the tetragonality and grain size increase and the shear piezoelectric coefficients (k15, g15 and d15) improve. For KNN ceramics, the results reveal that the values for remanent polarization as well as for most of the coercive field are quite similar among all compositions. These facts evidenced that Cu2+ may be incorporated into the A and/or B sites of the perovskite structure, having both hardening and softening effects.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

et al. 2016

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“…As ferroelectric material, barium titanate (BaTiO 3 ) has been paid more attention due to its high dielectric constant, ferroelectric activity, spontaneous polarization and nonlinear optical coefficients [1][2][3]. Not only for fundamental research but also for device applications, BaTiO 3 has great potential for technological applications in ferroelectricity, microelectronics and optoelectronics.…”

Section: Introductionmentioning

confidence: 99%

Structure and electrical properties of BaTiO3 prepared by sol–gel process

Chu

et al. 2009

Journal of Alloys and Compounds

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“…13 It is well-known that impurity or additive incorporation in BaTiO 3 in even quite small proportions may change the dielectric properties appreciably, e.g., Sb-doped BaTiO 3 4 and Ba 1¹x Na x Ti 1¹y Nb y O 3 . 5 On the other hand, perovskite BaMoO 3 is reported to be a good electrical conductor with resistivities in the range of 10100 ³ cm. 6 However, substitution of titanium by molybdenum in BaTiO 3 has, to our knowledge, not been reported.…”

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confidence: 99%

Synthesis and Crystal Structure of Cubic Perovskite-type BaMoxTi1−xO3 with x ≈ 0.175

Kataoka¹,

Kijima²,

HayakawaHiroshi³

et al. 2011

Chemistry Letters

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Single crystals of a novel solid-solution compound BaMo xTi 1¹x O 3 (x µ 0.175) in a BaTiO 3 and BaMoO 3 system were successfully grown by flux in Ar at 1423 K using the BaCO 3 B 2 O 3 system flux. The obtained crystals were black and rectangular with a maximum dimension of 0.2 © 0.2 © 0.3 mm 3 . The EDX and EPMA analyses confirmed the MoTi solid solution composition. Single-crystal X-ray structure analysis revealed the cubic perovskite structure, space group Pm 3m and the lattice parameters of a = 4.0112(6) ¡ and V = 64.54(3) ¡ 3 . The chemical composition and crystal structure were refined by the present structure refinement with the conventional values of R = 1.69% and wR = 1.89% using 156 independent observed reflections.Barium titanium oxide ceramics are important industrial materials. The perovskite BaTiO 3 and hexagonal BaTiO 3 have been extensively investigated because of their electric properties for use in dielectric and relaxor materials. 13 It is well-known that impurity or additive incorporation in BaTiO 3 in even quite small proportions may change the dielectric properties appreciably, e.g., Sb-doped BaTiO 3 4 and Ba 1¹x Na x Ti 1¹y Nb y O 3 . 5 On the other hand, perovskite BaMoO 3 is reported to be a good electrical conductor with resistivities in the range of 10100 ³ cm.6 However, substitution of titanium by molybdenum in BaTiO 3 has, to our knowledge, not been reported. In the present study, single crystals of the solid-solution compound BaMo xTi 1¹x O 3 with x µ 0.175 were successfully grown by flux, and the crystal structure was refined by single-crystal X-ray diffraction.Single crystals of BaMo x Ti 1¹x O 3 were synthesized by flux using a BaCO 3 B 2 O 3 system. The as-prepared Ba 2 Ti 13 O 22 powder 7 was mixed with BaCO 3 (99.9%) and B 2 O 3 (99.9%) in order to form a flux material with a nominal mass ratio of Ba 2 Ti 13 O 22 :BaCO 3 :B 2 O 3 = 1:5:5. The mixture was placed in Mo crucibles, heated in Ar at 1423 K for 10 h, and then cooled on standing. The products were easily separated from the frozen flux by rinsing the crucibles in hot water for several hours.The qualitative chemical composition of the products was investigated by scanning electron microscopyenergy dispersive X-ray analysis (SEM-EDX, JEOL JSM-5400) and electron probe microanalysis (EPMA, JEOL JXA-8100).Integrated intensity data were collected on a Rigaku AFC-7S four-circle diffractometer at 295 K using selected singlecrystal specimens. The electron density distribution was analyzed by the maximum entropy method (MEM) using the present single-crystal X-ray diffraction data with the PRIMA program. 8 The obtained three-dimensional electron density distributions were visualized with the VESTA program. 9Black single crystals of BaMo x Ti 1¹x O 3 with a maximum size of 0.2 © 0.2 © 0.3 mm 3 were grown in the frozen flux, as shown in Figure 1. The crystal surfaces were covered with the polycrystalline BaBO flux materials which were hardly removed by washing even using hot water. The good quality of the obtained rectangular cryst...

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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

Cited by 15 publications

References 9 publications

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

Structure and electrical properties of BaTiO3 prepared by sol–gel process

Synthesis and Crystal Structure of Cubic Perovskite-type BaMoxTi1−xO3 with x ≈ 0.175

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