The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba0.70Sr0.30TiO3 ceramics

Stanculescu, R.; Ciomaga, Cristina Elena; Horchidan, Nadejda; Galassi, Carmen; Tufescu, Florin Mihai; Mitoşeriu, Liliana

doi:10.1016/j.ceramint.2015.08.141

Cited by 16 publications

(7 citation statements)

References 41 publications

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“…Tunability (25 %) close to ours has been achieved in a BST-1%Mn-4%MgO ceramic [28], but at a higher electric field (1 kV/mm) and with slightly higher losses (tand = 5.10 -3 ). Other comparisons can be made [29][30][31] which show that our tunability and dielectric loss values are located among the best reported up to now, so demonstrating that the novel STLT materials constitute effective ferroelectric compositions, moreover without the need of a doping or a combination with a dielectric compound.…”

Section: Discussionsupporting

confidence: 54%

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Marlec

Paven

Cheviré

et al. 2018

Journal of the European Ceramic Society

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The present study reveals the ferroelectric nature of the novel (Sr 2 Ta 2 O 7 ) 100-x (La 2 Ti 2 O 7 ) x layered perovskite materials and highlights a large variation of their permittivity under electric fields associated with very low dielectric loss in the radio-frequency range. More precisely, an ideal solid solution has been evidenced within the composition range 0 ≤ x ≤ 5 with lattice parameters and cell volume varying linearly with x. The relative permittivity also depends on the composition and reaches a maximum value (365 @10kHz, RT), associated with a high tunability (17.6 % @0.38 kV/mm) with very low dielectric loss lower than 2.10 -3 . Variation of the relative permittivity as a function of the temperature is also demonstrated, with the existence of a temperature maximum, increasing with the composition. Polarization-electric field (P-E) measurements feature hysteresis loops for compositions x ≥ 1.85, in conjunction with current peaks in the I-E curves originating from ferroelectric domains switching.Keywords : perovskiteferroelectrictunability -Sr 2 Ta 2 O 7 -La 2 Ti 2 O 7

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Section: Discussionsupporting

confidence: 54%

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Marlec

Paven

Cheviré

et al. 2018

Journal of the European Ceramic Society

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“…A continuous reduction in the saturation and remnant polarization ( P s and P r ) and of the loop area and rectangularity factor P r / P s , with increasing the porosity level, is noticed (Table ). Thus, the porosity of the ceramic samples affects the nonlinear ferroelectric response . The decrease in polarization can be easily understood first of all by considering the presence of the air pores, which are regions characterized by zero ferroelectric polarization.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, the porosity of the ceramic samples affects the nonlinear ferroelectric response. [36][37][38] The decrease in polarization can be easily understood first of all by considering the presence of the air pores, which are regions characterized by zero ferroelectric polarization. However, it is observed that this polarization reduction is not proportional with the reduction in the material density and other effects should be considered.…”

Section: Microstructure and Phase Characteristicsmentioning

confidence: 99%

Porosity‐dependent properties of Nb‐doped Pb(Zr,Ti)O₃ ceramics

et al. 2016

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In the present work, it is shown how the controlled porosity can be exploited to obtain a compromise between a reduced permittivity down to a few hundreds and maintaining a high tunability level as in the dense material, to fulfill requirements for tunable applications. Nb‐doped Pb(Zr,Ti)O3 ceramics with porosity in the range 5%‐30% have been prepared by direct sintering method. X‐ray diffraction analysis and Rietveld refinement indicated a co‐existence of tetragonal and monoclinic phases in the porous ceramics. Dielectric properties revealed a gradual reduction in permittivity when increasing the porosity level, while maintaining low dielectric losses below 3%. The ferroelectric switching behavior is also influenced by the porosity level: a continuous reduction in the saturation and remnant polarization is observed with increasing porosity. The nonlinear dielectric properties of all the investigated ceramics preserve a high level of tunability in comparison with one of the dense material, irrespective of the porosity level, while zero field permittivity was decreased below 1000. An optimum behavior is found for the ceramic sample with 25% porosity, which shows a high tunability, smaller losses, and moderate dielectric constant (ε ~600).

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“…The effect of the annealing process on oxygen vacancies and related electrical inhomogeneity in porous and dense barium strontium ceramics was recently discussed [25,26]. The final properties are influenced by the localization of oxygen vacancies at the grain boundaries and/ or within the grains and their diffusion pathway during the annealing.…”

Section: Introductionmentioning

confidence: 99%

Fast re-oxidation kinetics and conduction pathway in Spark Plasma Sintered ferroelectric ceramics

Legallais

Fourcade

Chung

et al. 2018

Journal of the European Ceramic Society

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The re-oxidation kinetics of BaTiO3 ceramics sintered by Spark Plasma Sintering (SPS) was investigated using in-situ impedance spectroscopy. Thanks to the flexibility of the SPS process, the grain size of the dense ceramics was tuned from 0.5m to 10m. The reoxidation kinetics are found to be very fast regardless of the grain size and a full re-oxidation of the ceramics are achieved after 20 hours of exposure to an ambient environment at only 600°C. The residual density of charge carriers is reduced when using finer starting powders.SPS ceramics made with micrometer size grains demonstrate a residual charge-carrier density that is one tenth that of ceramics made from 10µm particles. Grain-boundary conduction is dominant through fine-grain SPS ceramics. This latter feature is similar to BaTiO3 sintered using the conventional route with 10m size grain. Finally, the critical grain size for optimal dielectric permittivity is found to shift from 0.7m in standard ceramics to 1.5m in SPS ceramics.

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The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba0.70Sr0.30TiO3 ceramics

Cited by 16 publications

References 41 publications

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Porosity‐dependent properties of Nb‐doped Pb(Zr,Ti)O₃ ceramics

Fast re-oxidation kinetics and conduction pathway in Spark Plasma Sintered ferroelectric ceramics

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The influence of post-sintering re-oxidation treatment on dielectric response of dense and porous Ba0.70Sr0.30TiO3 ceramics

Cited by 16 publications

References 41 publications

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Ferroelectricity and high tunability in novel strontium and tantalum based layered perovskite materials

Porosity‐dependent properties of Nb‐doped Pb(Zr,Ti)O3 ceramics

Fast re-oxidation kinetics and conduction pathway in Spark Plasma Sintered ferroelectric ceramics

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Product

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Porosity‐dependent properties of Nb‐doped Pb(Zr,Ti)O₃ ceramics