Effect of defect on the nonlinear and dielectric property of Ca(1–)Sr Cu3Ti4O12 ceramics synthesized by sol–gel process

Li, Tao; Liu, Dewei; Hirata, Dai; Xiang, Huiwen; Chen, Zhenping; He, H. F.; Chen, Zhiquan

doi:10.1016/j.jallcom.2014.02.076

Cited by 29 publications

(5 citation statements)

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“…As reported by Moura et al, the band gap of CCTO decreased and consequently an increase in the PL emission is noted with the increase of Zr 4+ doping, producing shortrange distortion in the perovskite structure due to the formation of [TiO 5 /TiO 6 ] cluster [37]. Some studies analyzed the substitution of Ca 2+ by Sr 2+ in the CCTO [35,38], but few studies have emphasized the role of partial and total substitutions of the Cu 2+ ions. The changes in the PL property of the CCTO phase with the partial and total substitution of Cu 2+ by Sr +2 in the presence of SCTO phase have been reported by a small number of authors [39][40][41].…”

Section: Introductionmentioning

confidence: 92%

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Orrego

Cortés

Amoresi

et al. 2018

Ceramics International

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Sr 2+ modified CaSr x Cu 3-x Ti 4 O 12 ceramic powders with x = ranging from 0.00 to 3.00 were prepared by solidstate reaction. The effects of Sr 2+ CCTO powders were evaluated by X-ray diffraction (XRD) with Rietveld refinement revealing a mixture of multiple phases. The Raman spectroscopy analysis pointed out that Sr 2+ addition produces an emission in the blue region, associated to TiO 6 clusters. Optical properties by means of PL analysis showed emission near to blue region for the samples with x = 0.00, x = 0.15, x = 0.30, corresponding to oxygen vacancies. The emission in the violet region is associated to deep defects while emission in the other samples is linked to shallow defects typical of disordered crystalline structures. Less prominent emission in the green region with the increase of Sr 2+ corresponds to less self-trapped charges, less interaction between electron and hole, and donor-acceptor recombination.

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Section: Introductionmentioning

confidence: 92%

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Orrego

Cortés

Amoresi

et al. 2018

Ceramics International

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“…The decrease of τ 2 and the increase of I 2 indicate that Cr 2 O 3 with high melting point can effectively reduce the volume of cation vacancy group in CuFeO 2 lattice, but increase the vacancy concentration. The mean lifetime τ m mainly reflects the total defect condition near the positron annihilation sites including the delocalized annihilation process in free and trapped states, which can be calculated in light of the formula [38]:…”

Section: Pals Analysismentioning

confidence: 99%

Regulation of Cr³⁺ doping on the defect characteristics and magnetic order in the CuFe_1-xCr_xO₂ ceramics

Sun

et al. 2021

Journal of Asian Ceramic Societies

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The defect characteristic and magnetic properties of CuFe 1-x Cr x O 2 (x = 0.0-0.4) compounds have been investigated in detail. The results demonstrate that Cr 3+ ions enter into the CuFeO 2 lattice sites and induce local lattice contraction but do not change the valance state of Cu + and Fe 3+ ions. We calculate the positron annihilation lifetime in the bulk and vacancy defect trapping states by the atomic superposition method in 3 × 3 × 1 CuFeO 2 super-cell. Combined with theoretical calculation results, the positron annihilation results indicate that the positrons are mainly annihilated in vacancy clusters in CuFe 1-x Cr x O 2 . The substitution of Cr 3 + for Fe 3+ ions decreases the open volume and increases the concentration of vacancy defects but does not change the integral defect surroundings at annihilation sites. Magnetization measurements manifest that doping with Cr 3+ reduces the antiferromagnetic transition temperature and promotes the formation of short-range magnetic correlation. Meanwhile, the enhanced short-range magnetic correlation in Cr 3+ -doped CuFeO 2 is more readily driven by thermal activation energy and a faster dynamic behavior can be seen in time windows.

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“…Among the Sr-CCTO specimens reported by Xue et al [33], Sr-CCTO-2, with Sr doping concentration of 10%, exhibited the highest permittivity and the lowest nonlinear coefficient. In a study by Li et al [15] the dielectric properties demonstrated that, with dopant weight % ≤ 0.15, Sr doping in CCTO not only increased dielectric permittivity but also reduced dielectric loss; however, it also reduced the dependence on frequency at low frequencies. In addition, we have taken different particle size of starting ingredients for the preparation of CSCTO-15.…”

Section: Introductionmentioning

confidence: 99%

Structural, electrical and dielectric characteristics of strontium-modified CaCu3Ti4O12

2018

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In order to produce an ultra-high dielectric constant and low loss factor in a polycrystalline material of Sr +2-modified (concentration 15%) CaCu 3 Ti 4 O 12 (i.e., Ca 0.85 Sr 0.15 Cu 3 Ti 4 O 12 , abbreviated as CSCTO-15) was prepared using a cost-effective solid-state reaction technique. Structural analysis using Rietveld refinement of the X-ray diffraction data has confirmed that the sample crystallizes in a cubic system with space group symmetry of Im3. Morphological/microstructural analysis of the natural surface of a pellet shows dense grain growth, with clearly visible grain boundaries. The dielectric relaxation mechanism of CSCTO-15 has been revealed by the detailed study of frequency-and temperature-dependent dielectric parameters (ε r and tan δ). Analysis of the frequency and temperature dependence of impedance and related parameters, collected by a complex impedance spectroscopic technique, has provided and estimated the contributions of grain, grain boundaries and electrode in the electrical process in the material. The activation energy at high temperatures has been calculated from the temperature-dependent ac conductivity plots at selected frequencies.

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Effect of defect on the nonlinear and dielectric property of Ca(1–)Sr Cu3Ti4O12 ceramics synthesized by sol–gel process

Cited by 29 publications

References 29 publications

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Regulation of Cr³⁺ doping on the defect characteristics and magnetic order in the CuFe_1-xCr_xO₂ ceramics

Structural, electrical and dielectric characteristics of strontium-modified CaCu3Ti4O12

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Effect of defect on the nonlinear and dielectric property of Ca(1–)Sr Cu3Ti4O12 ceramics synthesized by sol–gel process

Cited by 29 publications

References 29 publications

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Photoluminescence behavior on Sr 2+ modified CaCu 3 Ti 4 O 12 based ceramics

Regulation of Cr3+ doping on the defect characteristics and magnetic order in the CuFe1-xCrxO2 ceramics

Structural, electrical and dielectric characteristics of strontium-modified CaCu3Ti4O12

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Product

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Regulation of Cr³⁺ doping on the defect characteristics and magnetic order in the CuFe_1-xCr_xO₂ ceramics