Grain size effect on the dielectric and non-ohmic properties of CaCu3Ti4O12 ceramics prepared by the sol-gel process

Mao, Pu; Wang, Jiping; Liu, Shujuan; Zhang, Lixue; Zhao, Yingying; He, Liqiang

doi:10.1016/j.jallcom.2018.11.200

Cited by 93 publications

(52 citation statements)

References 42 publications

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“…The ε ′ values decrease with increasing number of (Li + , F − ) co‐dopant ions, which is similar to the behavior reported in Y 3+ ‐ and Sc 3+ ‐doped CCTO ceramics . However, this observation is unlike to that found in most other reports, in which the dielectric response of CCTO usually increases with increasing mean grain size . According to the Maxwell‐Wagner (M‐W) polarization model, the ε ′ is dependent on the capacitance at the GBs ( C gb ) .…”

Section: Resultssupporting

confidence: 80%

“…Recently, giant dielectric materials belonging to the family of ACu 3 Ti 4 O 12 compounds have generated considerable interest due to their potential applications for the miniaturization of microelectronic devices, for example, multilayer ceramic capacitors. CaCu 3 Ti 4 O 12 (CCTO) is a popular material among the ACu 3 Ti 4 O 12 compounds because it exhibits a very large dielectric permittivity ( ε ′ ~10 4 ) over a wide temperature range without a detectable phase transition in the temperature range of 35‐100 K . However, a structural phase transition occurred in CCTO ceramics at 726‐732 K .…”

Section: Introductionmentioning

confidence: 99%

“…However, many intrinsic effects that occur at the crystal structure level have been proposed to describe the unusual tremendous dielectric response . Interestingly, CCTO polycrystalline ceramics also show a nonlinear current‐voltage ( J ‐ E ) characteristic . According to the extrinsic model, the dielectric behavior from each point of view should be reasonably explained by the IBLC model, while the overall dielectric properties should be controlled by improving the electrical properties of the semiconducting and insulating phases.…”

Section: Introductionmentioning

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: Resultssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

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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“…Mao et al . have synthesized CCTO using calcium nitrate Ca(NO 3 ) 2 ⋅ 4H 2 O, copper nitrate Cu(NO 3 ) 2 ⋅ 3H 2 O, titanium isopropoxide (Ti(C 3 H 9 O) 4 , citric acid (C 6 H 8 O 7 ) and ethylene glycol (C 2 H 6 O 2 ) as starting materials.…”

Section: Synthesis Methodsmentioning

confidence: 99%

From Synthesis to Applications: Copper Calcium Titanate (CCTO) and its Magnetic and Photocatalytic Properties

et al. 2019

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Investigations focusing on electrical energy storage capacitors especially the dielectric ceramic capacitors for high energy storage density are attracting more and more attention in the recent years. Ceramic capacitors possess a faster charge‐discharge rate and improved mechanical and thermal properties compared with other energy storage devices such as batteries. The challenge is to obtain ceramic capacitors with outstanding mechanical, thermal and storage properties over large temperature and frequencies ranges. ABO 3 as a type of perovskites showed a strong piezoelectric, dielectric, pyroelectric, and electro‐optic properties useful as energy storage and environmental devices. CaCu 3 Ti 4 O 12 (CCTO) perovskite with cubic lattice (Im3 symmetry) was discovered to have a colossal dielectric constant (10 4 ) that is stable over a wide range of frequencies (10 Hz–1 MHz) and temperature independence (100–300 K). The origin of this high dielectric constant is not fully established, specially because it is the same for single crystal and thin films. In this review, the history of CCTO will be introduced. The synthesis and the sintering approaches, the dopant elements used as well as the applications of CCTO will be reported. In addition to dielectrical properties useful to energy storage devices; CCTO could serve as photocatalytic materials with a very good performance in visible light.

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“…This increased conductivity means that we have a greater amount of charge to polarize, thus resulting in a higher colossal permittivity. This helps explain how the large variation in growth conditions can change the permittivity . Critically, this result also explains the positive correlation between oxygen vacancy concentration and colossal permittivity…”

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confidence: 67%

The Fundamental Mechanism Behind Colossal Permittivity in Oxides

Taylor

Davies

et al. 2019

Advanced Materials

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Colossal permittivity materials exhibit extreme polarization in an applied electric field, providing applications in electronics and energy transmission. Understanding the atomic‐scale mechanism behind colossal permittivity remains a challenging task and is key to optimizing materials with this property. The fundamental mechanism of colossal permittivity is reported and, using CaCu3Ti4O12 as an example, it is attributed to the formation of an unusual metallic interface between the grain and grain boundary materials (CaCu3Ti4O12 and CuxO (x = 1, 2), respectively), not created by oxygen vacancies as is normally the case in oxide materials. This metallic layer around the grain forms confined shells of charge that pool on one side when under an applied field, which results in colossal permittivity. A route towards enhancing colossal permittivity is explained by means of manipulating the interface properties, as well as altering sample geometries. A methodology to artificially engineer colossal permittivity metamaterials is also shown.

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Grain size effect on the dielectric and non-ohmic properties of CaCu3Ti4O12 ceramics prepared by the sol-gel process

Cited by 93 publications

References 42 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

From Synthesis to Applications: Copper Calcium Titanate (CCTO) and its Magnetic and Photocatalytic Properties

The Fundamental Mechanism Behind Colossal Permittivity in Oxides

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Grain size effect on the dielectric and non-ohmic properties of CaCu3Ti4O12 ceramics prepared by the sol-gel process

Cited by 93 publications

References 42 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

From Synthesis to Applications: Copper Calcium Titanate (CCTO) and its Magnetic and Photocatalytic Properties

The Fundamental Mechanism Behind Colossal Permittivity in Oxides

Contact Info

Product

Resources

About

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