Enhanced dielectric and non-ohmic properties in CaCu3Ti4O12/CaTiO3 nanocomposites prepared by a chemical combustion method

Jumpatam, Jutapol; Thongbai, Prasit

doi:10.1007/s10854-016-5358-8

Cited by 13 publications

(5 citation statements)

References 30 publications

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“…No possible impurity phase, e.g., CuO or SrTiO 3 , was observed. This observation is similar to those reported in the literature for the CCTO/CTO composites [20,21,26,28,32], which comprised of~66.7 mol% CCTO and~33.3 mol% CTO [18,28,29]. The nominal composition of CCTO/CTO can be written as Ca(Cu 2 Ca)Ti 4 O 12 , which is similar to that of CCTO.…”

Section: Resultssupporting

confidence: 89%

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

et al. 2021

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The microstructure, dielectric response, and nonlinear current-voltage properties of Sr2+-doped CaCu3Ti4O12/CaTiO3 (CCTO/CTO) ceramic composites, which were prepared by a solid-state reaction method using a single step from the starting nominal composition of CCTO/CTO/xSrO, were investigated. The CCTO and CTO phases were detected in the X-ray diffraction patterns. The lattice parameter increased with increasing Sr2+ doping concentration. The phase compositions of CCTO and CTO were confirmed by energy-dispersive X-ray spectroscopy with elemental mapping in the sintered ceramics. It can be confirmed that most of the Sr2+ ions substituted into the CTO phase, while some minor portion substituted into the CCTO phase. Furthermore, small segregation of Cu-rich was observed along the grain boundaries. The dielectric permittivity of the CCTO/CTO composite slightly decreased by doping with Sr2+, while the loss tangent was greatly reduced. Furthermore, the dielectric properties in a high-temperature range of the Sr2+-doped CCTO/CTO ceramic composites can be improved. Interestingly, the nonlinear electrical properties of the Sr2+-doped CCTO/CTO ceramic composites were significantly enhanced. The improved dielectric and nonlinear electrical properties of the Sr2+-doped CCTO/CTO ceramic composites were explained by the enhancement of the electrical properties of the internal interfaces.

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Section: Resultssupporting

confidence: 89%

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

et al. 2021

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“…To better evaluate the nonlinear J – E characteristics of the optimized CCTO–STO composite ceramic samples, we compare the E b and α values of the 0.9CCTO–0.1STO composite ceramics in the current study with those of other reported CCTO-based composite ceramics in previous literature studies. ,− , As depicted in Figure , it is evident that our composite ceramics (0.9CCTO–0.1STO sample) shows a superior breakdown field and nonlinear coefficient among the other reported CCTO-based composite ceramics, indicating the excellent nonlinear properties achieved in the CCTO–STO system in this work. Our results illustrate that the CCTO ceramics with doped STO can realize the super-high nonlinear performances, and the CCTO–STO composite ceramics could potentially become promising candidates for the applications in varistor devices.…”

Section: Results and Discussionmentioning

confidence: 87%

“…However, the unresolved challenges in the CCTO perovskite material are that it shows a relatively large dielectric loss and low electric breakdown field, which in electrical operations are undesired for practical applications. Most recently, it is demonstrated that optimizing the fabrication process, − substituting ions of the A-site and B-site, , and introducing a second phase − have been employed to tune electrical heterogeneity and the potential barrier layer based on the IBLC effect, and thereby, improving the dielectric and nonlinear properties of CCTO ceramics. The common notion is that the desired high permittivity, relatively low dielectric loss, as well as the high breakdown field strength of CCTO ceramics are difficult to balance simultaneously, and thus, achieving the optimized dielectric and nonlinear properties is still a huge challenge.…”

Section: Introductionmentioning

confidence: 99%

Excellent Capacitor–Varistor Properties in Lead-Free CaCu₃Ti₄O₁₂–SrTiO₃ System with a Wrinkle Structure via Interface Engineering

Mao

Wang

et al. 2020

ACS Appl. Mater. Interfaces

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Lead-free perovskite CaCu 3 Ti 4 O 12 (CCTO) dielectrics are extremely important candidates for capacitor−varistor dual-function materials. However, their overall success in applications is somewhat controlled by the longstanding issues such as relatively large dielectric loss and insufficiently high electric breakdown field. Herein, we report the success in the preparation of an optimized lead-free (1−x)CaCu 3 Ti 4 O 12 −xSrTiO 3 (CCTO− STO) composite system with improved dielectric and nonlinear properties via interface engineering. Interestingly, looking closer at the grain boundaries using transmission electron microscopy, it is found that an obvious interface region with a transition layer of a wrinkled structure is formed between the CCTO matrix phase and STO dopant phase. Significantly, all the composite ceramic samples present high permittivity in the order of about 10 3 to 10 4 , and the 0.9CCTO−0.1STO composite ceramic sample exhibits a lower dielectric loss of about 0.068 at room temperature and at 1 kHz. Excitingly, the optimized 0.9CCTO−0.1STO composite ceramic sample also exhibits a remarkably elevated breakdown field strength of about 14.03 kV/cm and a large nonlinear coefficient of about 16.11. The improvement in nonlinear properties with a high breakdown field strength and large nonlinear coefficient could be attributed to the interfacial effect in the composite structure, originating from the formation of the transition layer with a wrinkle structure at the interface between CCTO and STO phases. Such effects can result in great electrical heterogeneity caused by the higher resistance of the grain boundary and the enhanced potential barrier at the interface region. The new insights on the formation of the interfacial wrinkle structure near the phase boundaries of the CCTO−STO composite system and their effects on improvement of electrical properties can stimulate future research on lead-free CCTO−STO-based systems toward capacitor−varistor dual-function applications and may offer an effective way to design other lead-free dielectric materials as well.

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“…Although the origins of the giant dielectric response in CCTO ceramics have been thus unclear, improvement of dielectric properties and electrical response of this ceramic have been continuously achieved. − The first severe problem, namely, a high loss tangent (tan δ), has been addressed in several works. Improved preparation methods such as a wet chemical route, chemical combustion, modified solid state reaction, spark plasma sintering, and quick quenching were used to prepare high-performance CCTO ceramics. Additionally, substitution of metal ions into the CCTO lattice can also improve both the dielectric and nonlinear electrical properties of these materials.…”

Section: Introductionmentioning

confidence: 99%

Strongly Enhanced Dielectric Response and Structural Investigation of (Sr²⁺, Ge⁴⁺) Co-Doped CCTO Ceramics

et al. 2020

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A solid–state reaction method was used to prepare (Sr2+, Ge4+) co-doped CaCu3Ti4O12 ceramics. A single-phase of CaCu3Ti4O12 was detected in all the ceramics. An enormous evolution of grain growth in (Sr2+, Ge4+) co-doped CaCu3Ti4O12 ceramics was observed, which was due to a liquid phase sintering mechanism. Theoretical calculations showed that Ge dopant ions are more likely substituted in Cu sites rather than Ti sites. High dielectric permittivity, ∼69,889, with a low dielectric loss tangent, ∼0.038, was achieved in a Ca0.95Sr0.05Cu3Ti3.95Ge0.05O12 ceramic. Furthermore, dielectric permittivity at 1 kHz of this ceramic is more temperature-stable than that of the CaCu3Ti4O12 and Ca0.95Sr0.05Cu3Ti4O12 ceramics. The enhanced dielectric permittivity with reduced loss tangent in the co-doped ceramics originated from a metastable insulating phase created by a liquid phase sintering mechanism. The local insulating phase along the grain boundary layers can increase the grain boundary resistance as well as the conduction activation energy of the grain boundaries, resulting in a decreased dielectric loss tangent. An internal barrier layer capacitor model supports the origin of the giant dielectric properties in CaCu3Ti4O12-based ceramics by all results in this work.

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Enhanced dielectric and non-ohmic properties in CaCu3Ti4O12/CaTiO3 nanocomposites prepared by a chemical combustion method

Cited by 13 publications

References 30 publications

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

Excellent Capacitor–Varistor Properties in Lead-Free CaCu₃Ti₄O₁₂–SrTiO₃ System with a Wrinkle Structure via Interface Engineering

Strongly Enhanced Dielectric Response and Structural Investigation of (Sr²⁺, Ge⁴⁺) Co-Doped CCTO Ceramics

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Enhanced dielectric and non-ohmic properties in CaCu3Ti4O12/CaTiO3 nanocomposites prepared by a chemical combustion method

Cited by 13 publications

References 30 publications

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

Excellent Capacitor–Varistor Properties in Lead-Free CaCu3Ti4O12–SrTiO3 System with a Wrinkle Structure via Interface Engineering

Strongly Enhanced Dielectric Response and Structural Investigation of (Sr2+, Ge4+) Co-Doped CCTO Ceramics

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Product

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Excellent Capacitor–Varistor Properties in Lead-Free CaCu₃Ti₄O₁₂–SrTiO₃ System with a Wrinkle Structure via Interface Engineering

Strongly Enhanced Dielectric Response and Structural Investigation of (Sr²⁺, Ge⁴⁺) Co-Doped CCTO Ceramics