Effect of sintering temperature and Cu-rich secondary phase on dielectric properties of microwave processed CaCu3Ti4O12 ceramics

Samanta, Buddhadev; Kumar, P.; Prakash, Chandra

doi:10.1080/00150193.2017.1369829

Cited by 15 publications

(13 citation statements)

References 29 publications

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“…DC gold sputtering was used for surface coating to avoid electron accumulation during FESEM study. This whole synthesis procedure was also reported in our previous work [1]. Abbreviations used for the samples are CCTO1, CCTO2, CCTO3 and CCTO4 in accordance with successive increase in the sintering temperature (from 1000 to 1075°C).…”

Section: Methodsmentioning

confidence: 80%

“…Co-K α (λ = 1.789010 Å) radiation (Bruker D8) was used for X-ray diffraction study. Structural refinement was carried out by Rietveld analysis using cubic CCTO with monoclinic CuO secondary phase, which was reported earlier [1]. Dielectric properties were previously studied [1] as a function of frequency (100 Hz to 1 MHz) and temperature (room temperature to 150°C).…”

Section: Methodsmentioning

confidence: 99%

“…Structural refinement was carried out by Rietveld analysis using cubic CCTO with monoclinic CuO secondary phase, which was reported earlier [1]. Dielectric properties were previously studied [1] as a function of frequency (100 Hz to 1 MHz) and temperature (room temperature to 150°C). In this present work, temperature dependance of dielectric properties was studied within the temperature range from room temperature to 300°C at four discrete frequencies (1, 10, 100 and 1000 kHz) using LCR meter (Hioki 3532-50, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…CaCu 3 Ti 4 O 12 (CCTO) shows an unusual variation of perovskite structure. Having pseudo perovskite crystal structure, CCTO has attracted considerable considerable interest due to its colossal dielectric permittivity at room temperature (≈ 10 4 -10 6 ), which remains almost constant over a wide temperature and frequency range [1][2][3][4]. Practical applications of CCTO based systems can enhance the performance and miniaturization of microelectronic devices by virtue of its excellent dielectric Microwave processing of ceramics is very attractive technique for material synthesis because of its advantages like very fast heating, increased densification, decreased sintering activation energy, improved microstructure, selective heating, non-contact heating, grain growth inhibition, energy and cost savings compared to conventional processing of electroceramics etc.…”

Section: Introductionmentioning

confidence: 99%

“…Practical applications of CCTO based systems can enhance the performance and miniaturization of microelectronic devices by virtue of its excellent dielectric Microwave processing of ceramics is very attractive technique for material synthesis because of its advantages like very fast heating, increased densification, decreased sintering activation energy, improved microstructure, selective heating, non-contact heating, grain growth inhibition, energy and cost savings compared to conventional processing of electroceramics etc. [1].…”

Section: Introductionmentioning

confidence: 99%

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Giant dielectric response in microwave processed CaCu3Ti4O12 ceramics: A correlation among microstructure, dielectric and impedance properties

Samanta

Nanda

Kumar

et al. 2019

PAC

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Polycrystalline CaCu 3 Ti 4 O 12 (CCTO) ceramics was synthesized by microwave assisted solid-state reaction. Effect of sintering at different temperatures on the crystal structure, dielectric and impedance properties was investigated in detail. Rietveld analysis of X-ray diffraction data identified that crystal structure was a mixture of cubic CCTO and monoclinic CuO phases. Lattice parameters and amount of CuO secondary phase were also estimated as a function of sintering temperature. Microstructural investigation confirmed the existance and successive increase of the melted phase near the grain boundary region with increasing temperature of sintering. Cu-rich nature of the melted phase was further confirmed by selective area EDX spectra. Dielectric and impedance properties were studied as a function of frequency (100 Hz to 1 MHz) and temperature (room temperature to 300°C). Improvement in dielectric properties as a function of sintering temperature (1000 to 1050°C) was explained in terms of reduction in grain boundary dimension due to the successive increase in Cu-rich melted phase. However, dielectric constant started falling when sintered at 1075°C, which may be accounted in terms of segregation of large amount of CuO phase after a certain temperature and hence a non-stoichiometry of Cu in CCTO lattice. Impedance data were modelled by equivalent electrical circuits to investigate different contributions of electrically heterogeneous systems. In addition, probable relaxation mechanism has been discussed on the basis of impedance and modulus data. Activation energies were calculated from different characterizations and a non-Debye-type relaxation phenomena were observed. In this work, an attempt is made to build up a correlation among synthesis procedure, sintering temperature, dielectric, impedance and microstructural properties.

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Section: Methodsmentioning

confidence: 80%

Section: Methodsmentioning

confidence: 99%