Structures, dielectric and ferroelectric properties of Sr2-xCaxNaNb5O15lead-free ceramics

Wei, Lingling; Yang, Zupei; Han, Xiaokun; Li, Zhaohu

doi:10.1557/jmr.2012.32

Cited by 24 publications

(12 citation statements)

References 15 publications

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“…In this structure mono or divalent cations can be accommodated at the A-sites (A 1 and A 2 ), tri or pentavalent cations at octahedral sites (B 1 and B 2 ) and C-site is generally have small ions or empty. It is expected that the substitutions of varieties of cations at the A and B sites change the crystal structure and physical properties of materials significantly due to their different atomic/ionic size and charge distribution [11][12][13][14][15]. Most of the TB structure belongs to tetragonal or orthorhombic structure with small distortion of multiple perovskites.…”

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confidence: 99%

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀

Das

Sutar

Pati³

et al. 2014

Ferroelectrics

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The polycrystalline sample of a new tungsten bronze ferroelectric vanadate, Li 2 Pb 2 La 2 W 2 Ti 4 V 4 O 30 , was prepared at a relatively low temperature using a mixedoxide technique. The formation of the material under the reported conditions has been confirmed by an X-ray diffraction technique. A preliminary structural analysis exhibits orthorhombic crystal structure of the material at room temperature. Studies of dielectric properties (ε, tanδ) of the above compound as a function of temperature (273-600K) at frequencies 10, 100, 1000 KHz exhibits a ferroelectric phase transition of diffuse type. The electrical properties of the material have been studied using ac impedance spectroscopy technique. Detailed studies of impedance and related parameters exhibit that the electrical properties of the material are strongly dependent on temperature, and bear a good correlation with its microstructures. The temperature dependence of electrical relaxation phenomenon in the materials has been observed. The bulk resistance, evaluated from complex impedance spectra, is found to decrease with rise in temperature, exhibiting a typical negative temperature co-efficient of resistance (NTCR) -type behavior similar to that of semiconductors. A small contribution of grain boundary effect was also observed. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation. The ac conductivity spectra exhibit a typical signature of an ionic conducting system, and are found to obey Jonscher's universal power law.

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confidence: 99%

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀

Das

Sutar

Pati³

et al. 2014

Ferroelectrics

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“…The ambiguity in the literature as to space groups for SNN may in part relate to structural variations associated with different synthesis conditions. In a further example of the uncertainties in indexing diffraction patterns, a recent study of Ca 2+ modified SNN reports a tetragonal phase for SNN with no Ca 2+ substitution, changing to orthorhombic with increasing levels of Ca 2+ substitution [24,27]. Verification of the true crystal system of SNN produced in our laboratory must await a detailed future study using electron and neutron diffraction.…”

Section: Resultsmentioning

confidence: 91%

PersonalitySensing: A Multi-View Multi-Task Learning Approach for Personality Detection based on Smartphone Usage

Gao

Song

et al. 2020

Proceedings of the 28th ACM International Conference on Multimedia

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High relative permittivity, ε r , over a very wide temperature range, -65°C to 325°C, is presented for ceramics designed to be compatible with base metal electrode multilayer capacitor manufacturing processes. We report a ≥ 300°C potential Class II capacitor material free from Bi or Pb ions, developed by doping Sr 2 NaNb 5 O 15 with Ca 2+ ,Y 3+ and Zr 4+ ions, according to the formulation Sr 2-2z Ca z Y z NaNb 5-z Zr z O 15 . For sample composition z = 0.025, ε r values are 1565 ± 15 % (1 kHz) from -65°C to 325°C. At a slightly higher level of doping, z = 0.05, ε r values are 1310 ± 10 % from -65°C to 300°C. Values of the dielectric loss tangent, tanδ are ≤ 0.025 from −60°C to 290°C, for z = 0.025, with tanδ increasing to 0.035 at 325°C. Microstructural analyses exclude core-shell mechanisms being responsible for the flattening of the ε r -T response.

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“…The perovskite-type NSN phase was also detected using powder X-ray and neutron diffraction in 'filled' TB Sr 2 NaNb 5 O 15 ceramics [21]. Torres-Pardo et al showed that the 'filled' TB SCNN compounds were easily contaminated by the perovskite-type Na 0.5 Sr 0.25 NbO 3 phase due to the solid solution limit [21,22]. According to Fig.…”

Section: Resultsmentioning

confidence: 99%

“…have shown that the ceramics with x = 0.15 showed better electrical properties and had application prospects in lead-free electronic components [15,22]. In this work, The phase structure of the prepared ceramics samples was characterized using Xray diffraction (XRD; D/max-2200, Rigaku, Japan, Cu Kα) with a scanning step of 0.02° over a 2θ range of 20-60°.…”

Section: Studies Involving the Effects Of Sr/ca Ratio On Electrical Pmentioning

confidence: 99%

Electrical and transparent properties induced by structural modulation in (Sr0.925Ca0.075)2.5–0.5Na Nb5O15 ceramics

Yang

Hao

et al. 2017

Journal of the European Ceramic Society

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The effects of Na + concentration on the microstructural, dielectric, ferroelectric and transparent properties of (Sr 0.925 Ca 0.075) 2.5−0.5x Na x Nb 5 O 15 (SCNN; 0.4 ≤ x ≤ 1.0) ceramics prepared using a conventional solid-state reaction method were investigated. X-ray diffraction results showed that the phase structure transitioned from tetragonal to orthorhombic tungsten bronze along with the structural type changing from 'unfilled' to 'filled' state. The NbO 6 octahedron became more distorted and had higher interaction strength when introducing Na + in A-sites to decrease the structural vacancies, leading to the improvement of dielectric and ferroelectric properties. The dielectric spectra of all specimens showed two broad dielectric anomalies: a hightemperature anomaly (the ferroelectric phase transition) and a low-temperature anomaly caused by the subtle structural effects in 'unfilled' SCNN ceramics, which evolved into the ferroelastic phase transition in 'filled' SCNN ceramics.

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Structures, dielectric and ferroelectric properties of Sr_2-xCa_xNaNb₅O₁₅lead-free ceramics

Abstract: Abstract

Cited by 24 publications

References 15 publications

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀

PersonalitySensing: A Multi-View Multi-Task Learning Approach for Personality Detection based on Smartphone Usage

Electrical and transparent properties induced by structural modulation in (Sr0.925Ca0.075)2.5–0.5Na Nb5O15 ceramics

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Structures, dielectric and ferroelectric properties of Sr2-xCaxNaNb5O15lead-free ceramics

Abstract: Abstract

Cited by 24 publications

References 15 publications

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li2Pb2La2W2Ti4V4O30

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li2Pb2La2W2Ti4V4O30

PersonalitySensing: A Multi-View Multi-Task Learning Approach for Personality Detection based on Smartphone Usage

Electrical and transparent properties induced by structural modulation in (Sr0.925Ca0.075)2.5–0.5Na Nb5O15 ceramics

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Structures, dielectric and ferroelectric properties of Sr_2-xCa_xNaNb₅O₁₅lead-free ceramics

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀

Structural and Electrical Properties of Complex Tungsten Bronze Ferroelectrics ; Li₂Pb₂La₂W₂Ti₄V₄O₃₀