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Journal ArticleDOI: 10.1016/J.JALLCOM.2020.158216

Electrical features of ferroelectric (Ba0.83Ca0.17)TiO3 ceramics with diffused phase transition under pressure

05 Mar 2021-Journal of Alloys and Compounds (Elsevier)-Vol. 856, pp 158216
Abstract: Ferroelectric (Ba0.83Ca0.17)TiO3 ceramics was sintered by the solid state reaction method. The material was sintered in three steps that allowed remarkably modifying structure and electrical features important from an application point of view. Major tetragonal phase of the material was detected using X-ray diffraction study. The scanning electron microscope test showed fluctuation in chemical composition. The ferroelectric to paraelectric phase transition was diffused and markedly shifted to lower temperature, TC = 339 K, respectively to barium titanate. Moreover, it showed the pressure sensitivity dTC/dp = −37 K/GPa. These effects were attributed to local disorder both in Ba/Ca and Ti sublattices. The high magnitude dielectric permittivity, e′~1000–2000, was observed in 200–400 K temperature range. The net polarization, which was estimated from the pyroelectric effect, decreased from ~3 µC/cm2 to zero in ~100–400 K range. The ceramics displayed the piezoelectric coefficient, d33 = 58 pC/N, the spontaneous polarization, PS = 11–14 µC/cm2, the remnant polarization, PR~2 µC/cm2, the coercive field, EC~1.5–3 kV/cm, and the energy density storage efficiency factor, ξ ≈ 33%, at room temperature.

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Topics: Barium titanate (60%), Ferroelectricity (60%), Dielectric (57%) ... show more

7 results found

Journal ArticleDOI: 10.1016/J.APMT.2021.101125
Yameng Zhu1, Mengdan Guan1, Jin Wang1, Huixiang Sheng1  +5 moreInstitutions (2)
Abstract: Owing to the extraordinary optical properties, plasmonic nanostructures have been applied in many fields, particularly in triggering or accelerating chemical reactions. Because of the unique features of the surface plasmon, various inorganic nanomaterials, especially the ones with complex nanostructures, have been obtained with the assistance of plasmon excitation, producing nanocrystals that are difficult to fabricate by traditional methods. Writing up a comprehensive and timely review on this topic is essential to its further developments. This review summarizes the principle of plasmon excitation and its contribution in the growth, etching, and phase transition of inorganic nanocrystals. First, the excitation of surface plasmon is introduced, followed by the discussion of three effects, localization of electromagnetic field, excitation of hot carriers, and local heating, in plasmon-mediated transformation of nanocrystals. Then, the applications of surface plasmon in nanocrystal transformation are fully introduced in five categories, controlled growth of metal nanocrystals, controlled growth of oxide nanocrystals, growth of chiral nanostructures, site-selective etching of nanocrystals, and phase transition of nanocrystals. Finally, remaining challenges and future opportunities in this field are discussed. This review will benefit the fabrication of various-shaped inorganic nanocrystals and their applications in diverse fields.

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Topics: Surface plasmon (58%), Plasmon (57%)

3 Citations

Journal ArticleDOI: 10.1016/J.JHAZMAT.2021.126792
Abstract: Over more than three decades, the field of engineering of photocatalytic materials with unique properties and enhanced performance has received a huge attention. In this regard, different classes of materials were fabricated and used for different photocatalytic applications. Among these materials, recently multifunctional XTiO3 perovskites have drawn outstanding interest towards environmental remediation and energy conversion thanks to their unique structural, optical, physiochemical, electrical and thermal characteristics. XTiO3 perovskites are able to initiate different surface catalytic reactions. Under ultrasonic vibration or heating, XTiO3 perovskites can induce piezo-catalytic reactions due to the titling of their conduction and valence bands, resulting in the formation of separated charge carriers in the medium. In addition, under light irradiation, XTiO3 perovskites are considered as a new class of photocatalysts for environmental and energy related applications. Herein, we addressed the recent advances on variously synthesized, doped and formulated XTiO3 perovskite-type oxides showing piezo- and/or photocatalytic exploitation in environmental remediation and energy conversion. The control of structural crystallite size and phase, conductivity, morphology, oxygen vacancy control, doping agents and ratio has a significant role on the photocatalytic and piezocatalytic activities. The different piezo or/and photocatalytic processes mechanistic pathways towards varying applications were discussed. The current challenges facing these materials and future trends were addressed at the end of the review.

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2 Citations

Journal ArticleDOI: 10.1080/01411594.2021.1940181
30 Jun 2021-Phase Transitions
Abstract: The present work is a demonstration of improved electrical and optical properties of barium zirconium titanate ceramic modified by the addition of Europium, i.e. Ba(1–x)Eu2x/3Zr0.05Ti0.95O3 (x = 0....

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Topics: Ceramic (59%), Europium (56%), Barium (53%)

Open access
30 Nov 2002-
Abstract: Fine-grained dielectric ceramics, i.e., of 0.2 µm grain diameter, were obtained using Ca-doped BaTiO3 powders consisting of particles 0.2 µm in diameter. The (Ba1-xCax)mTiO3 ceramics (x: 0–0.10, m: 1.003–1.009) showed a high dielectric constant and stable temperature dependence, which were provided by interfacial stress due to the grain boundary, even though the ceramics has no core-shell structure. The failure time under an accelerated life condition was remarkably improved with Ca doping, which may be caused by the decrease in BaTiO3 unit volume with Ca2+ at the Ba2+ lattice site, and Ca2+ acceptor ions at the Ti4+ site.

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Topics: Barium titanate (60%), Dielectric (56%), Ceramic (56%) ... show more

Journal ArticleDOI: 10.1016/J.CERAMINT.2021.07.038
Tianyi Zheng1, Han Zhao2, Yiqian Huang1, Chenyuan Gao1  +3 moreInstitutions (2)
Abstract: The piezoelectric nature of natural bone tissue makes the use of piezoelectric biomaterials in promoting bone regeneration to be a feasible and attractive strategy. Barium titanate (BaTiO3) is well-known for its high piezoelectricity and widely studied as bone repairing bioceramic, but its lacking of bioactive ions may compromise its contribution to osteogenesis. Calcium is the richest metallic element in bone mineral, and manganese is an important doping element for hydroxyapatite, therein, Ca2+ and Mn4+ were individually or co-doped into BaTiO3 nanofibers via sol-gel/electrospinning/calcination technique in this study. Compared to pure BaTiO3 nanofibers, though the piezoelectric coefficient (d33) of Ca2+ and/or Mn4+-doped BaTiO3 nanofibers decreased with increase in ion doping amount, it could maintain approx. 0.9–3.7 pC/N and comparable to that of native bone (0.7–2.3 pC/N) at an optimized content. Under the synergistic effect of the released bioactive ions and the material piezoelectricity, the BaTiO3 nanofibers co-doped with Mn4+ (2 mol%) and Ca2+ (10 mol%) (i.e., the sample 2Mn10Ca-BT) achieved the strongest capacity in enhancing the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs), while showing no cytotoxicity. In summary, bioactive ions-doped BaTiO3 nanofibers are promising scaffolds for bone tissue engineering, thanks to their acceptable biocompatibility, appropriate piezoelectricity, and improved osteogenic activity.

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Topics: Bone regeneration (60%), Nanofiber (56%), Barium titanate (51%) ... show more


74 results found

Journal ArticleDOI: 10.1107/S0567739476001551
Abstract: The effective ionic radii of Shannon & Prewitt [Acta Cryst. (1969), B25, 925-945] are revised to include more unusual oxidation states and coordinations. Revisions are based on new structural data, empirical bond strength-bond length relationships, and plots of (1) radii vs volume, (2) radii vs coordination number, and (3) radii vs oxidation state. Factors which affect radii additivity are polyhedral distortion, partial occupancy of cation sites, covalence, and metallic character. Mean Nb5+-O and Mo6+-O octahedral distances are linearly dependent on distortion. A decrease in cation occupancy increases mean Li+-O, Na+-O, and Ag+-O distances in a predictable manner. Covalence strongly shortens Fe2+-X, Co2+-X, Ni2+-X, Mn2+-X, Cu+-X, Ag+-X, and M-H- bonds as the electronegativity of X or M decreases. Smaller effects are seen for Zn2+-X, Cd2+-X, In2+-X, pb2+-X, and TI+-X. Bonds with delocalized electrons and therefore metallic character, e.g. Sm-S, V-S, and Re-O, are significantly shorter than similar bonds with localized electrons.

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Topics: Ionic radius (55%), Lanthanide contraction (53%), Electronegativity (51%)

46,405 Citations

Open accessBook
06 Oct 1977-
Abstract: The book develops the modern theory of ferroelectricity in terms of soft modes and lattice dynamics and also describes modern techniques of measurement, including X-ray, optic, and neutron scattering, infra-red absorption, and magnetic resonance. It includes a discussion of the related phenomena of antiferroelectricity, pyroelectricity, and ferroelasticity and seconds on domains, thin films, ceramics, and polymers, leading on to a comprehensive survey of potential and actual device capabilities for pyroelectric detection, memories, display, and modulation. It should provide an authoritative account for those engaged in research or graduate ferroelectric or pyroelectric devices.

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Topics: Antiferroelectricity (54%), Ferroelasticity (52%), Ferroelectricity (51%)

4,806 Citations

Journal ArticleDOI: 10.1038/NATURE03028
04 Nov 2004-Nature
Abstract: Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300 picocoulombs per newton (pC N(-1)), and texturing the material leads to a peak d33 of 416 pC N(-1). The textured material also exhibits temperature-independent field-induced strain characteristics.

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Topics: Ceramic (54%), Piezoelectricity (52%), Potassium niobate (50%)

4,295 Citations

Journal ArticleDOI: 10.1111/J.1551-2916.2009.03061.X
Jürgen Rödel1, Wook Jo1, Klaus T. P. Seifert1, Eva-Maria Anton1  +2 moreInstitutions (2)
Abstract: A large body of work has been reported in the last 5 years on the development of lead-free piezoceramics in the quest to replace lead–zirconate–titanate (PZT) as the main material for electromechanical devices such as actuators, sensors, and transducers. In specific but narrow application ranges the new materials appear adequate, but are not yet suited to replace PZT on a broader basis. In this paper, general guidelines for the development of lead-free piezoelectric ceramics are presented. Suitable chemical elements are selected first on the basis of cost and toxicity as well as ionic polarizability. Different crystal structures with these elements are then considered based on simple concepts, and a variety of phase diagrams are described with attractive morphotropic phase boundaries, yielding good piezoelectric properties. Finally, lessons from density functional theory are reviewed and used to adjust our understanding based on the simpler concepts. Equipped with these guidelines ranging from atom to phase diagram, the current development stage in lead-free piezoceramics is then critically assessed.

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2,271 Citations

Journal ArticleDOI: 10.1007/S10832-007-9047-0
Thomas R. Shrout1, Shujun Zhang1Institutions (1)
Abstract: Investigations in the development of lead-free piezoelectric ceramics have recently claimed comparable properties to the lead-based ferroelectric perovskites, represented by Pb(Zr,Ti)O3, or PZT In this work, the scientific and technical impact of these materials is contrasted with the various families of “soft” and “hard” PZTs On the scientific front, the intrinsic nature of the dielectric and piezoelectric properties are presented in relation to their respective Curie temperatures (T C) and the existence of a morphotropic phase boundary (MPB) Analogous to PZT, enhanced properties are noted for MPB compositions in the (Na,Bi)TiO3-BaTiO3 and ternary system with (K,Bi)TiO3, but offer properties significantly lower The consequences of a ferroelectric to antiferroelectric transition well below T C further limits their usefulness Though comparable with respect to T C, the high levels of piezoelectricity reported in the (K,Na)NbO3 family are the result of enhanced polarizability associated with the orthorhombic-tetragonal polymorphic phase transition being compositionally shifted downward As expected, the properties are strongly temperature dependent, while degradation occurs through the thermal cycling between the two distinct ferroelectric domain states Extrinsic contributions arising from domains and domain wall mobility were determined using high field strain and polarization measurements The concept of “soft” and “hard” lead-free piezoelectrics were discussed in relation to donor and acceptor modified PZTs, respectively Technologically, the lead-free materials are discussed in relation to general applications, including sensors, actuators and ultrasound transducers

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Topics: Ferroelectricity (54%), Piezoelectricity (52%), Dielectric (51%) ... show more

1,367 Citations