Structural and dielectric properties of A- and B-sites doped CaCu3Ti4O12 ceramics

Thomas, Ajith; Abraham, K. E.; Thomas, Jini; Saban, K.V.

doi:10.1016/j.ceramint.2015.04.138

Cited by 34 publications

(9 citation statements)

References 23 publications

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“…The sintering process was seen to produce ceramics with relative density about 90%, the results are presented in Figure . The CC X T Y O ceramics present densification consistent with the values that are reported in the literature, where the highest densities can reach values up to 95% …”

Section: Resultssupporting

confidence: 88%

Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Gelfuso

Uribe

Thomazini

2018

Int J Applied Ceramic Tech

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The influence of the CuO-TiO 2 phase (CT) on dielectric properties of the CCTO ceramic was investigated. CaCu X Ti Y O 12 (CC X T Y O) powders were prepared based on the coprecipitated method, where 2.70 ≤ x ≤ 3.30 and 3.25 ≤ y ≤ 4.75. XRD patterns confirmed the presence of CCTO and also the secondary phases as CuO, TiO 2 , and CaTiO 3 for each sample and aided in its quantification. Scanning Electron Microscopy (SEM) shows secondary phases evolution in the grain boundaries, and its influence on size and morphology of the grains. Impedance spectroscopy measurements showed that the ceramics with lower amount of CuO and TiO 2 phases (CT/deficient ceramics) exhibited the highest ε′ values (2.1 × 10 4 at 1 kHz for CC 2.9 T 3.75 O ceramic). Also, CT/deficient ceramics showed lower tanδ values (0.090 at 1 kHz for CC 2.9 T 3.75 O ceramic) than ceramics prepared with excessive CuO-TiO 2 phase (0.241 at 1 kHz for CC 3.1 T 4.25 O ceramics). The deficiency of CuO and TiO 2 phases associated with high percentage of CCTO and CaTiO 3 phases resulted in ceramics with the higher ε′ values.

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Section: Resultssupporting

confidence: 88%

Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Gelfuso

Uribe

Thomazini

2018

Int J Applied Ceramic Tech

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“…From the figure it is observable that the sample is marked with a dense microstructure containing a uniform arrangement of grains with an average grain size of 3 μm. A notable reduction in the grain size compared to that of CCTO (50–100 μm) 21 is seen when the A ‐site is substituted with Sm. Lower porosity and better uniformity in grain size might have triggered the development of a dense ceramic that possesses a density of about 94.9% of that of the theoretical value.…”

Section: Resultsmentioning

confidence: 93%

Giant dielectric constant, dielectric relaxations, and tunable properties of Sm_2/3Cu₃Ti₄O₁₂ ceramics

Thomas¹,

George²,

Abraham³

et al. 2020

Int J Applied Ceramic Tech

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The polycrystalline Sm2/3Cu3Ti4O12 (SCTO) ceramics have been prepared by solid‐state reaction. The crystallinity of the compound has been investigated by Rietveld refinement which has revealed a cubic structure with space group Im3. It is observed that at low frequencies, SCTO ceramic exhibits tremendously high values of dielectric permittivity ε′, larger than 32,000, at room temperature. Two distinct, thermally triggered, dielectric relaxations have been noted. This mechanism has been confirmed through impedance analysis of the ceramics. The complex impedance plane shows three semicircles, which confirm the existence of two dielectric relaxations in SCTO ceramics. In general, the electrical as well as dielectric behavior of SCTO ceramics are seen to be reasonably analogous to those of CaCu3Ti4O12 (CCTO) ceramics. The emergence of the enormous dielectric constant in SCTO ceramic is accredited to the combined effect of polarization both at the sample‐electrode interface as well as at the insulating grain boundary interface. The SCTO ceramics are identical to the CCTO ceramics in their structure and composition and hence, as the above results indicate, the IBLC effect mechanism, originally put forward for CCTO ceramics, is furthermore plausible to account for the mammoth values of dielectric constant in SCTO ceramics.

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“…5. When Sn 4þ enters into the CTO lattice interstitially (12) Equations (9-12) would help to explain the non-ohmic response. However, we conclude that samples with low Sn 4þ substituted samples (x ¼ 0.1 and 0.2) may be solely governed by the defects reactions present in equations (4)e (8).…”

Section: Resultsmentioning

confidence: 99%

Dielectric and non-ohmic properties of Ca2Cu2Ti4-xSnxO12 (0.0 ≤ x ≤4.0) multiphasic ceramic composites

Cortés

Cotrim

Orrego

et al. 2018

Journal of Alloys and Compounds

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Multiphasic Sn 4þ substituted Ca 2 Cu 2 Ti 4-x Sn x O 12 (0.0 x 4.0) ceramic composites were prepared by solid-state reaction. Their crystalline structure, microstructure, dielectric and non-ohmic properties were investigated. The electric properties and the densification and grain growth mechanisms were strongly influenced by a mixture of multiple phases, as evidenced by X-ray diffraction (XRD). The materials with low Sn 4þ contents (x ¼ 0.1 and 0.2) presented giant dielectric permittivity values, 166381 and 140845 respectively. This should be associated to insulating grain boundaries with activation energies of 0.58 eV and 0.30 eV respectively, as well as conductive grains with activation energies of 0.04 eV and 0.08 eV. On the other hand, samples with higher ionic substitution (x ¼ 3.8, 3.9 and 4.0) revealed a new type of tinbased ceramic composites, which exhibit non-linear coefficients (a) of 3.0, 4.0 and 4.0, respectively. A new multiphase ceramic composites with high dielectric performance and non-ohmic properties are summarized.

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Structural and dielectric properties of A- and B-sites doped CaCu3Ti4O12 ceramics

Cited by 34 publications

References 23 publications

Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Giant dielectric constant, dielectric relaxations, and tunable properties of Sm_2/3Cu₃Ti₄O₁₂ ceramics

Dielectric and non-ohmic properties of Ca2Cu2Ti4-xSnxO12 (0.0 ≤ x ≤4.0) multiphasic ceramic composites

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Structural and dielectric properties of A- and B-sites doped CaCu3Ti4O12 ceramics

Cited by 34 publications

References 23 publications

Deficient or excessive CuO‐TiO2 phase influence on dielectric properties of CaCu3Ti4O12 ceramics

Deficient or excessive CuO‐TiO2 phase influence on dielectric properties of CaCu3Ti4O12 ceramics

Giant dielectric constant, dielectric relaxations, and tunable properties of Sm2/3Cu3Ti4O12 ceramics

Dielectric and non-ohmic properties of Ca2Cu2Ti4-xSnxO12 (0.0 ≤ x ≤4.0) multiphasic ceramic composites

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Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Deficient or excessive CuO‐TiO₂ phase influence on dielectric properties of CaCu₃Ti₄O₁₂ ceramics

Giant dielectric constant, dielectric relaxations, and tunable properties of Sm_2/3Cu₃Ti₄O₁₂ ceramics