Structural, Dielectric and Ferroelectric Studies of Tungsten Substituted Barium Strontium Titanate

Devi, Sheela; Jha, A. K.

doi:10.1080/00150191003709347

Cited by 10 publications

(5 citation statements)

References 21 publications

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“…In order to preserve the electrical neutrality of the unit cell, compensation mechanisms are activated, which are involved in creating V Ti , V Ba , V O vacancies. Literature reports indicate that, for low concentrations of lanthanum, neutrality of the crystal lattice is achieved by generating oxygen vacancies, which confirms the pale blue color of the obtained samples [11,[24][25][26].…”

Section: Dielectric Propertiessupporting

confidence: 80%

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

et al. 2020

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This paper describes the properties of a lead-free ceramic material based on barium titanate, designed for the construction of ultracapacitors and sensors used in mechatronic systems. The admixture of lanthanum (La3+) served as a modifier. The ceramic powders were obtained by the solid phase reaction method (conventional method—mixed oxides method—MOM). Technological conditions of the synthesis process were determined on the basis of thermal analysis. The obtained samples are characterized, at room temperature (Tr < TC), by a single-phase tetragonal structure and a P4mm space group. Properly developed large grains (d = 5 µm) contributed to the increase in electric permittivity, the maximum value of which is at the level of εm ≈ 112,000, as well as to a strong decrease in specific resistance in the ferroelectric phase, whereas above the Curie temperature, by creating a potential barrier at their boundaries, there was a a rapid increase in resistivity. The temperature coefficient of resistance of the obtained posistor is 10.53%/K. The electrical properties of the obtained ceramics were examined using impedance spectroscopy. In order to analyze the obtained results, a method of comparing the behavior of the real object and its replacement system in a specific frequency region was used, whereas the Kramer–-Kroning (K–K) test was used to determine the consistency of the measured data. The proper selection of the stoichiometry and synthesis conditions resulted in the creation of an appropriate concentration of donor levels and oxygen gaps, which in turn resulted in a significant increase in the value of electrical permittivity, with small values of the angle of dielectric loss tangent. This fact predisposes the discussed material for certain applications (in the construction of ultracapacitors, among others).

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Section: Dielectric Propertiessupporting

confidence: 80%

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

et al. 2020

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“…The decrease in the value of the dielectric constant upon further addition of Pb is due to porosity present in the samples. Apart from this, a substantial shift in the value of T c from 120°C for pure BaTiO 3 to 170°C for Ba 0.80 Pb 0.20 TiO 3 was also noted, which was more than that seen with any other dopant used [29,[33][34][35][36][37][38][39][40][41] (refer to Table 2).…”

Section: Resultsmentioning

confidence: 90%

Significant improvement in Curie temperature and piezoelectric properties of BaTiO₃with minimum Pb addition

Butee

Kambale

Ghorpade

et al. 2019

Journal of Asian Ceramic Societies

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Dense Ba 1-x Pb x TiO 3 (x = 0-0.20) samples (>90% TD) were fabricated through a solid-state reaction route involving wet ball milling for 24 h and calcination at 1150°C for 4 h, followed by sintering at 1300°C for 4 h. XRD results for all the samples revealed a tetragonal perovskite (P4mm) crystal structure. Increased substitution of Pb caused monotonic growth in the tetragonality character of the perovskite phase. Although, the value of ε r ʹ dropped from an initial value of 3000 for x = 0 (pure BaTiO 3) to 400 for x = 0.20 samples, the losses (tanδ) interestingly declined almost to half. A substantial increase in the Curie temperature from 120°C for x = 0°C to 180°C for x = 0.15 samples was noted. P-E loop analysis revealed an increase in the saturation polarization by almost 1.5 times, moreover, in the remnant polarization by six times with Pb-substitution. The d 33 values demonstrated an increase from 95 pC/N for pure BaTiO 3 samples to 220 pC/N for x = 0.15 samples.

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“…9. The dielectric constant e' of materials have four different polarization contributions: space charge polarization, dipolar polarization, ionic polarization and electronic polarization [88]. At lower frequency (1 Hz-1 kHz) and at intermediate frequency (1-100 kHz) ranges space charge polarization and dipolar polarization are dominated, respectively.…”

Section: Sem Image Analysesmentioning

confidence: 99%

Structural refinement, Raman spectroscopy, optical and electrical properties of (Ba1−xSrx)MoO4 ceramics

Ghosh

Rout

Tiwari

et al. 2015

J Mater Sci: Mater Electron

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In this paper, structural refinement, Raman spectroscopy, optical and electrical properties of barium strontium molybdate [(Ba 1-x Sr x )MoO 4 ] ceramics with different (x) contents (x = 0; 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; and 1) were synthesized by the solid state reaction method. These ceramics were structurally characterized by X-ray diffraction (XRD), Rietveld refinement, and micro-Raman spectroscopy. The shape of the grains for these ceramics was observed by means of scanning electron microscopy (SEM) images. The optical properties were investigated using ultraviolet-visible (UV-Vis) absorption spectroscopy and photoluminescence (PL) measurements. The dielectric and ferroelectric properties were analyzed by permittivity (e r ), loss tangent (tan d) and polarization versus electric field (P-E) hysteresis loop. XRD patterns, Rietveld refinement, and micro-Raman spectra showed that all ceramics are monophasic with a scheelite-type tetragonal structure. A decreased of lattice parameters and unit cell volume was observed with the increase of Sr 2? ions into BaMoO 4 lattice. Rietveld data were employed to model the [BaO 8 ], [SrO 8 ] and [MoO 4 ] clusters in the tetragonal lattices. The SEM images indicate that increased x content promotes a decrease in the grain size and modifications in the shape. UV-Vis spectra indicated a decrease in the optical band gap values with an increase in x content in the (Ba 1-x Sr x )MoO 4 ceramics. PL emissions exhibit a non-linear behavior to increase or decrease with the increase of Sr 2? ions in the tetragonal lattices, when excited by a wavelength of 350 nm. The P-E decreases along with slim hysteresis loop towards higher Sr 2? ions concentration. These effects are correlated with decrease in lattice parameters and c/a ratio in this tetragonal lattice. The microwave dielectric constant and quality factor were measured using the method proposed by Hakki-Coleman. Temperature coefficient and quality factor of these materials were measured by vector network analyzer.

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Structural, Dielectric and Ferroelectric Studies of Tungsten Substituted Barium Strontium Titanate

Cited by 10 publications

References 21 publications

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

Significant improvement in Curie temperature and piezoelectric properties of BaTiO₃with minimum Pb addition

Structural refinement, Raman spectroscopy, optical and electrical properties of (Ba1−xSrx)MoO4 ceramics

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Structural, Dielectric and Ferroelectric Studies of Tungsten Substituted Barium Strontium Titanate

Cited by 10 publications

References 21 publications

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

Chemical and Physical Properties of the BLT4 Ultra Capacitor—A Suitable Material for Ultracapacitors

Significant improvement in Curie temperature and piezoelectric properties of BaTiO3with minimum Pb addition

Structural refinement, Raman spectroscopy, optical and electrical properties of (Ba1−xSrx)MoO4 ceramics

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Significant improvement in Curie temperature and piezoelectric properties of BaTiO₃with minimum Pb addition