Impedance spectroscopy of Li2CO3 doped (Ba,Sr)TiO3 ceramic

Ham, Yong-Su; Koh, Jung‐Hyuk

doi:10.1016/j.solidstatesciences.2012.10.011

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…For peak 2 of the as‐sintered MWS samples, E a = 0.77 eV, consistent with Bi‐doped SrTiO 3 ceramics at the same temperature range, which was believed to attribute to the hopping of the electrons from the double ionization of oxygen vacancies or

V_{normalO}^{∙ ∙}

— related defect associations (like Ti 4+ /Ti 3+ ‐

V_{normalO}^{∙ ∙}

) . In perovskite structure materials, oxygen vacancies are easily created by oxygen loss from the crystal lattice due to the reducing atmosphere or high temperature (≥1350°C) during the sintering process, according to

{normalO}_{normalO} = \frac{1}{2} {normalO}_{2} + {V_{normalO}}^{∙} + e^{'}

{normalO}_{normalO} = \frac{1}{2} {normalO}_{2} + V_{O}^{∙ ∙} + 2 e^{'}

where

V_{normalO}^{∙}

and

V_{normalO}^{∙ ∙}

represent the oxygen vacancies carrying one and two excess positive charges, respectively.…”

Section: Resultssupporting

confidence: 59%

“…11(a)], being described as bulk response, as the sum of contributions from grains and grain boundaries (i.e., R bulk = R g + R gb , C bulk = C g + C gb ). The annealed sample can be simulated by an equivalent circuit consisting of two parallel R-C elements connected in series, related to the individual contribution from the grains and grain boundaries, 40,41 as shown in the inset 2 of Fig. 11(b).…”

Section: (3) Analysis On Annealing Effect Considering the Role Of Modmentioning

confidence: 99%

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Improved Energy Storage Properties Accompanied by Enhanced Interface Polarization in Annealed Microwave‐Sintered BST

et al. 2015

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Microwave‐sintering (MWS) technique was employed to fabricate dense (Ba0.4Sr0.6)TiO3 (BST) ceramics. With respect to the high dielectric loss at room temperature, induced by the formation of oxygen defects during the MWS under vacuum atmosphere (−60 kPa), the as‐sintered samples were thermally annealed in air to reduce tanδ and recover the insulating performance. Accompanied by the decreased tanδ, the energy storage properties for annealed MWS BST were optimized, with increasing energy density (γ) from 0.77 to 1.15 J/cm3 and energy efficiency (η) from 60% to 82%. The lower oxygen vacancy concentrations were believed to account for the enhanced insulating characteristics of grain boundaries and contribute to the improved properties after annealing. Electrical characterization of grain and grain boundary by impedance spectroscopy demonstrated that the annealing preferentially modified the grain boundary. In addition, resistances extracted from the high temperature impedance analysis were found to be inadequate for evaluating the electrical characteristics of materials affected by extrinsic mechanisms, such as the interfacial polarization. For comparison, annealing effect on energy storage properties were also discussed for conventionally sintered BST.

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V_{normalO}^{∙ ∙}

— related defect associations (like Ti 4+ /Ti 3+ ‐

V_{normalO}^{∙ ∙}

{normalO}_{normalO} = \frac{1}{2} {normalO}_{2} + {V_{normalO}}^{∙} + e^{'}

{normalO}_{normalO} = \frac{1}{2} {normalO}_{2} + V_{O}^{∙ ∙} + 2 e^{'}

where

V_{normalO}^{∙}

and

V_{normalO}^{∙ ∙}

represent the oxygen vacancies carrying one and two excess positive charges, respectively.…”

Section: Resultssupporting

confidence: 59%

Section: (3) Analysis On Annealing Effect Considering the Role Of Modmentioning

confidence: 99%

Improved Energy Storage Properties Accompanied by Enhanced Interface Polarization in Annealed Microwave‐Sintered BST

et al. 2015

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“…The dielectric properties of ferroelectric ceramics could be significantly modified by doping, by forming solid solutions or composites with other materials [14][15][16][17][18][19][20][21]. The ''dilution'' of their dielectric constant and minimization of the dielectric loss of BST-based materials can be achieved by adding amounts of non-ferroelectric dielectrics.…”

Section: Introductionmentioning

confidence: 99%

Study of the role of porosity on the functional properties of (Ba,Sr)TiO 3 ceramics

Stanculescu

Ciomaga

Padurariu

et al. 2015

Journal of Alloys and Compounds

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“…Sintering of BaTiO 3 -based dielectrics, including BST, is an intriguing topic of practical importance [7,8]. A variety of strategies have been employed to lower the sintering temperature of BST ceramics, such as adopting highly sinter-active BST powders synthesized by wet chemical routes as the starting powders [9,10], preparing the ceramics using novel sintering techniques [11,12] and adding sintering aids [13][14][15][16][17][18][19][20][21][22]. Among these strategies, adding sintering aids is the most convenient and commonly-used method.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, lithium additives are more effective in enhancing the sintering properties of BST ceramics. For example, adding small amounts of Li 2 CO 3 (1-5 wt%) into BST could lower the sintering temperature down to ~900 °C [19][20][21][22]. The low-temperature densification of Li 2 CO 3added BST ceramics suggests the presence of a liquid-phase during the sintering.…”

Section: Introductionmentioning

confidence: 99%

Enhanced sintering and nonlinear dielectric properties of Ba0.6Sr0.4TiO3 ceramics with a small amount of lithium additive

Zhang

Xie

et al. 2019

SCI SINTER

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The powders with the nominal compositions of Ba0.6Sr0.4TiO3+x wt.% Li2CO3 (x=0 and x=1.0) were synthesized by a citrate precursor method. The sintering behavior, structure and dielectric properties of the ceramic specimens were investigated. Compared with the lithium-free specimen (x=0), the lithium-added specimen (x=1.0) showed appreciably enhanced sintering properties, achieving a relative density of 96.0% after sintering at 900?C. The enhanced sintering properties were related to a liquid-phase sintering mechanism. The origin of the liquid-phase was explained. The effects of the liquid-phase on the densification progress of the lithium-added specimen in different sintering stages were elucidated. The lithium addition was found to be beneficial to the nonlinear dielectric properties. The ceramic specimen with x=1.0 exhibited a figure-of-merit of 106 under a bias electric field of 20 kV/cm, higher by ~60% than the value (67) for the specimen with x=0.

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Impedance spectroscopy of Li2CO3 doped (Ba,Sr)TiO3 ceramic

Cited by 11 publications

References 11 publications

Improved Energy Storage Properties Accompanied by Enhanced Interface Polarization in Annealed Microwave‐Sintered BST

Improved Energy Storage Properties Accompanied by Enhanced Interface Polarization in Annealed Microwave‐Sintered BST

Study of the role of porosity on the functional properties of (Ba,Sr)TiO 3 ceramics

Enhanced sintering and nonlinear dielectric properties of Ba0.6Sr0.4TiO3 ceramics with a small amount of lithium additive

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