High density nanostructured BaTiO3 ceramics obtained under extreme conditions

Alves, Marcos Fernando Soares; Gotardo, Ricardo Augusto Mascarello; Cótica, L. F.; Santos, I. A.; Nascimento, William Junior do; Garcia, D.; Eiras, J. A.

doi:10.1016/j.scriptamat.2012.02.044

Cited by 14 publications

(4 citation statements)

References 27 publications

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“…The absence of oxygen at high temperatures, and the presence of the argon flux, lead to the formation of oxygen vacancies at the ceramic grain boundaries (removal of surface oxygen ions by drag flow of argon) [25], and consequently, these vacancies tend to migrate to the entire grain (core) due to the elevated sintering temperature (1500 1C) used in this work. The vacancy migration, in a microscopic point of view, tends to affect the crystal lattice [25,26], global charge balance, crystal field, and consequently the valence state of the Eu ions in the garnet structure, since Al and Y ions are only found in the 3þ state at room temperature. This way, the coexistence of Eu 3 þ and Eu 2 þ ions in Eu:YAG ceramics is a direct consequence of the synthesis protocol for ceramics processing.…”

Section: Resultsmentioning

confidence: 99%

“…The results indicated that Cerium has assumed the Ce 3 þ valence state, while Eu ions had reached a mixed valence state, comprising the coexistence of Eu 2 þ and Eu 3 þ ions in the YAG host, as a direct consequence of the inert-gas flow sintering protocol. Ce:YAG and Eu:YAG powders were processed by high-energy ball milling by using optimized milling conditions as reported previously [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

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Processing and luminescence properties of Ce:Y3Al5O12 and Eu:Y3Al5O12 ceramics for white-light applications

et al. 2012

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Processing and luminescence properties of Ce:Y3Al5O12 and Eu:Y3Al5O12 ceramics for white-light applications

et al. 2012

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“…The studies related to the evolution of functional properties in BaTiO 3 dense structures when grain size reduces below 1 μm, attracted much interest in the last years . The dielectric constant of BaTiO 3 strongly depends on grain size (GS), and shows a maximum of ~5000 for grains in the range of 0.8–1 μm, which was attributed to critical changes in the domain structure.…”

Section: Introductionmentioning

confidence: 99%

Grain Size‐Dependent Properties of Dense Nanocrystalline Barium Titanate Ceramics

et al. 2012

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The grain size influence on the dielectric relaxation and nonlinear dielectric properties of BaTiO 3 ceramics with grain size in the range of (92Ä936) nm densified by Spark Plasma Sintering (SPS) from ultrafine powders were investigated. The progressive reduction of the Curie temperature and of the effective permittivity results from a combination of intrinsic size effects and low-permittivity grain boundary layer. A model of dielectric cylindrical cavities was employed in order to calculate intrinsic effective permittivity values in GHz range. An interesting feature is the presence of a thermally activated Debyelike relaxation in the ferroelectric state of ceramics with grain size above 300 nm, with activation energies of 0.45-0.49 eV, which seems to be related to the domain walls forced motion under the applied field. By diminishing grain size, a progressive reduction of the ferroelectric nonlinear character was obtained, reaching a macroscopic non-switching character and a linear permittivity versus field dependence for the finest ceramics (grain size of 90-100 nm) until very high values of the applied field. The observed behavior supports the idea of frozen polarization induced by pinning centers as due to a large number of grain boundaries and charged defects in the fine structures.

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“…Dense and crack-free BTO thin film was obtained from this method by finely controlling the solvent evaporation and pre-drying process. On the other hand, high-density nanostructured BTO ceramic was synthesized by Alves and co-workers [10] using an innovative processing route which involves high-energy ball-milling and spark plasma sintering. The as-prepared dense BTO thin film with high dielectric permittivity has shown potential application in multilayer capacitors.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

Liang

Wang

et al. 2016

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Dense and crack-free barium titanate (BaTiO3, BTO) thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet) deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film.

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High density nanostructured BaTiO3 ceramics obtained under extreme conditions

Cited by 14 publications

References 27 publications

Processing and luminescence properties of Ce:Y3Al5O12 and Eu:Y3Al5O12 ceramics for white-light applications

Processing and luminescence properties of Ce:Y3Al5O12 and Eu:Y3Al5O12 ceramics for white-light applications

Grain Size‐Dependent Properties of Dense Nanocrystalline Barium Titanate Ceramics

Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

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