Control of grain boundary in alumina doped CCTO showing colossal permittivity by core-shell approach

Almeida-Didry, Sonia De; Nomel, Meledje Martin; Autret-Lambert, Cécile; Honstettre, Christophe; Lucas, Anthony; Pacreau, François; Gervais, F.

doi:10.1016/j.jeurceramsoc.2018.03.003

Cited by 89 publications

(59 citation statements)

References 13 publications

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“…The (Li + , F − ) co‐dopants may play a primary role in the enlarged grain sizes. Such grain growth may be attributed to liquid‐phase sintering behavior, which is usually reported in CCTO ceramics . The low‐temperature eutectic liquid phase for CuO–TiO 2 occurs at approximately 919°C, and the low melting point of LiF (~846°C) is likely the primary source of the liquid phase during sintering.…”

Section: Resultsmentioning

confidence: 83%

“…Such grain growth may be attributed to liquid-phase sintering behavior, which is usually reported in CCTO ceramics. 10,11,14,33,36,38 The low-temperature eutectic liquid phase for CuO-TiO 2 occurs at approximately 919°C, 10,39 and the low melting point of LiF (~846°C) 40 is likely the primary source of the liquid phase during sintering. During the sintering process, charges diffuse more easily across the liquid phase than in the solid phase, giving rise to fast grain growth in the (Li + , F − ) co-doped CCTO ceramics.…”

Section: Resultsmentioning

confidence: 99%

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Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics

et al. 2019

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Giant dielectric behavior and electrical properties of monovalent cation/anion (Li+, F−) co‐doped CaCu3Ti4O12 ceramics prepared by a solid‐state reaction route were systematically investigated. Substitution of Li+ and F− led to a significantly enlarged mean grain size. A reduced loss tangent (tanδ ~0.06) with the retainment of an ultra‐high dielectric permittivity (ε′ ~7.7‐8.8 × 104) was achieved in the co‐doped ceramics, while the breakdown electric field and nonlinear coefficient of CaCu3Ti4O12 ceramics were increased by co‐doping with (Li+, F−). The variations in nonlinear electrical properties and giant dielectric response, as well as the dielectric relaxation, were well explained by the Maxwell‐Wagner polarization model for an electrically heterogeneous microstructure, in which a Schottky barrier height at the grain boundaries (GBs) was formed. ε′ was closely correlated to the GB capacitance. Significantly decreased tanδ value and enhanced nonlinear properties were related to a significant increase in the GB resistance, which was attributed to the significantly increased potential barrier height and conduction activation energy at the GBs. The semiconducting nature of the grains was also studied using X‐ray photoelectron spectroscopy and found to originate from the presence of Cu+ and Ti3+ ions.

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Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics

et al. 2019

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“…This is in agreement with results of this work. Sonia De Almeida-Didry et al [33] studied alumina doped CCTO prepared by the core-shell approach and they found that the grain boundaries of CCTO materials play a key role in the huge permittivity by controlling the density of grain boundaries. They demonstrated that core-shell design is an efficient technique to obtain a high dielectric constant, which shows obvious performance improvement.…”

Section: Resultsmentioning

confidence: 99%

Zn-Doped Calcium Copper Titanate Synthesized via Rapid Laser Sintering of Sol-Gel Derived Precursors

Huang

Qiao

et al. 2020

Nanomaterials

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Zn-doped calcium copper titanate (CCTO) was successfully synthesized by rapid laser sintering of sol-gel derived precursors without the conventional long-time heat treatment. The structural, morphological, and crystalline properties were characterized, and the performances of dielectrics and impedance were measured and discussed. The X-ray diffractometer results show that Zn-doped CCTO is polycrystalline in a cubic structure, according to the doping ratio of Ca(Cu2Zn)Ti4O12. Electron microscopy showed that Zn-doped CCTO has a denser microstructure with better uniformness with shrunken interplanar spacing of 2.598 nm for the plane (220). Comparing with undoped CCTO, the permittivity almost remains unchanged in the range of 102–106 Hz, demonstrating good stability on frequency. The electrical mechanism was investigated and is discussed through the impedance spectroscopy analysis. The resistance of grain and grain boundary decreases with rising temperature. Activation energies for the grain boundaries for Zn- doped CCTO were calculated from the slope for the relationship of ln σ versus 1/T and were found to be 0.605 eV, smaller than undoped CCTO. This synthesis route may be an efficient and convenient approach to limit excessive waste of resources.

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“…Secondly, the tanδ is reduced by enhancing the heterogeneity between grains and grain boundaries. Some ions, such as Zr 4+ [12][13][14], Al 3+ [15], Mg 2+ [16], Zn 2+ [9], Sr 2+ [17]and rare earth ions [18][19][20], are introduced into the lattice structure to successfully reduce the internal conductivity of the grains as well as to increase the R gb , achieving lower the tanδ of the ceramic. In addition, smaller tanδ and larger ε r are also obtained in CCTO ceramics by the doping of binary elements, such as Y 3+ and Mg 2+ [21], Zr 4+ and Nb 5+ [22], Al 3+ and Ta 5+ [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of ZrO2 Doping on the Microstructure and Dielectric Properties of Ca0.97Y0.03Cu3Ti4-xZrxO12 Ceramics

WEI

Zhang

et al. 2021

Preprint

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Dielectric properties of CaCu3Ti4O12 (CCTO) ceramics were studied by doping amount of Zr4+ donor on the basis of doping Y3+ donor. Ca0.97Y0.03Cu3Ti4-xZrxO12 (x=0, 0.005, 0.010, 0.015, CYCTZO) ceramics were prepared by reaction sintering method, and the phase structure, microstructure and dielectric properties of the ceramics were studied. The single phase CCTO was detected in all ceramic samples. SEM images of samples showed a high density and uniform-sized microstructure, and the average grain sizes of the ceramics was reduced with increasing content of Zr4+ donor. Interestingly, the dielectric constant (εr) was increased significantly while the dielectric loss tangent (tanδ) was decreased with the suitable doping amount of Zr4+. CYCTZO ceramics with x=0.010 exhibited a relatively high εr value of 1.02×105 at 1kHz. Meanwhile, the improved grain boundaries response and dielectric properties were closely related to the strengthened grain boundaries resistance (Rgb). The present results indicate that the εr was improved and the tanδ was reduced by doping Zr4+ donors in Ca0.97Y0.03Cu3Ti4O12 (CYCTO) ceramics and explained that the electrical properties were closely related to the electrical heterogeneity of ceramic grains and grain boundaries.

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Control of grain boundary in alumina doped CCTO showing colossal permittivity by core-shell approach

Cited by 89 publications

References 13 publications

Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics

Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics

Zn-Doped Calcium Copper Titanate Synthesized via Rapid Laser Sintering of Sol-Gel Derived Precursors

Effect of ZrO2 Doping on the Microstructure and Dielectric Properties of Ca0.97Y0.03Cu3Ti4-xZrxO12 Ceramics

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Control of grain boundary in alumina doped CCTO showing colossal permittivity by core-shell approach

Cited by 89 publications

References 13 publications

Giant dielectric behavior of monovalent cation/anion (Li+, F−) co‐doped CaCu3Ti4O12 ceramics

Giant dielectric behavior of monovalent cation/anion (Li+, F−) co‐doped CaCu3Ti4O12 ceramics

Zn-Doped Calcium Copper Titanate Synthesized via Rapid Laser Sintering of Sol-Gel Derived Precursors

Effect of ZrO2 Doping on the Microstructure and Dielectric Properties of Ca0.97Y0.03Cu3Ti4-xZrxO12 Ceramics

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Product

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Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics

Giant dielectric behavior of monovalent cation/anion (Li⁺, F⁻) co‐doped CaCu₃Ti₄O₁₂ ceramics