Effect of Yttrium Doping in Barium Zirconium Titanate Ceramics: A Structural, Impedance, and Modulus Spectroscopy Study

Badapanda, T.; Cavalcante, L. S.; Luz, Geraldo E.; Batista, N. C.; Anwar, Shahid; Longo, Elson

doi:10.1007/s11661-013-1770-3

Cited by 26 publications

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References 47 publications

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“…As an example, Fig. 36 The final refined parameters are listed in Table 1. The refinement proceeded using the structural data of Li 5 La 3 Sb 2 O 12 given by Cussen and Yip as an initial model.…”

Section: Resultsmentioning

confidence: 99%

“…For the Li 6 CaLaEuSb 2 O 12 sample, the R-values of the Rietveld refinement were 5.43%, 6.95%, 3.96%, 2.54% and 2.14, respectively; this indicated that the quality of the structural refinement is acceptable. 36 The final refined parameters are listed in Table 1. As seen from the Table 1, the Li 6 CaLaEuSb 2 O 12 crystal has the lattice parameters of a = b = c = 12.65 Å, and the calculated unit cell volume (V = 2024.28 Å 3 ) is slightly smaller than that of pure Li 5 La 3 Sb 2 O 12 (V = 2126.78 Å 3 ) crystal 37 because the effective ionic radius of Eu 3+ (r = 1.07 Å) is smaller than that of La 3+ (r = 1.16 Å).…”

Section: Resultsmentioning

confidence: 99%

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Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes

et al. 2015

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To alleviate the issues of low thermal stability and high correlated color temperature, exploring an inorganic color converter with both yellow-and red-emissions to replace the conventional resin/silicone-based phosphor converter for obtaining high-power warm white light-emitting diodes is highly desired. In this study, a series of garnet-based Li 6 CaLa 2À2x Eu 2x Sb 2 O 12 (x = 0.1-1.0) red phosphors have been successfully synthesized by a conventional high-temperature solid-state method. The microstructure and luminescence properties were systematically investigated by X-ray diffraction, emission/excitation spectra, luminescence lifetimes and temperature-dependent decays. The as-synthesized phosphors exhibited a highly efficient red luminescence at 611 nm corresponding to the 5 D 0 -7 F 2 electric dipole transition of Eu 3+ , and the luminescence monotonously enhanced as the Eu 3+ content was increased to 100 mol%. The absence of concentration quenching was ascribed to the large Eu 3+ -Eu 3+ distance (7.048-7.105 Å) and subsequently the hindering of unwanted energy migration among them in the Li 6 CaLa 2 Sb 2 O 12 crystalline lattice. Impressively, the Li 6 CaLaEuSb 2 O 12 phosphor showed an excellent thermal stability with only 9.7% emission loss when the recording temperature was increased from 293 K to 553 K. To evaluate the suitability of Li 6 CaLa 2 Sb 2 O 12 :Eu 3+ as a red converter, both the garnet-based Y 3 Al 5 O 12 :Ce 3+ yellow and Li 6 CaLa 2 Sb 2 O 12 :Eu 3+ red phosphor co-doped glass ceramics were successfully fabricated by a low-temperature co-sintering technique.Importantly, the adverse energy transfers between Ce 3+ and Eu 3+ were efficiently suppressed due to the spatial separation of Ce 3+ in Y 3 Al 5 O 12 and Eu 3+ in Li 6 CaLa 2 Sb 2 O 12 in the crystal lattice. As a consequence, the quantum yield of the glass ceramic reached as high as 89.3%, and the constructed white light-emitting diode exhibited an optimal luminous efficacy of 101 lm W À1 , a correlated color temperature of 5449 K and a color rendering index of 73.7. It is expected that the developed Li 6 CaLa 2À2x Eu 2x Sb 2 O 12 red phosphors and the related glass ceramics should have potential applications in high-power warm white light-emitting diodes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes

et al. 2015

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“…The [110] peak of BYT0.002 and BYT0.005 samples seemed to remain at the same position as of pure BT within the range of instrumental errors. However, the peak was clearly shifting towards higher 2θ values for BYT0.01 and BYT0.03 samples (Figure (ii)) . The substitution of yttrium at barium site leads to the distortion of lattice structure because of its smaller ionic radius.…”

Section: Resultsmentioning

confidence: 93%

Modulating the Effect of Yttrium Doping on the Structural and Dielectric Properties of Barium Titanate

Kumar

Thakur

Luthra

2018

Physica Status Solidi (a)

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In this paper, the influence of yttrium doping on the structural, dielectric, and piezoelectric properties of Ba1−1.5xYxTiO3 (x = 0–0.03) is investigated. The samples are synthesized using solid‐state route (SSR). The synthesized materials are analyzed by X‐ray diffraction (XRD), which indicated the formation of crystalline materials exhibiting tetragonal phase. The samples with composition x = 0.005 and 0.01 are denser relative to other samples. The dielectric constant and loss tangent are measured in the temperature range −30 to 250 °C for different frequencies. The dielectric constant increases upto x = 0.005 (7555 at 1 kHz) and decreases thereafter. The shifts in the transition temperature (Tc) are corroborated with differential scanning calorimetry (DSC) studies. The electron paramagnetic resonance (EPR) data reveals that yttrium occupied Ti‐site after a certain limit of dissolution at Ba‐site. Modified Curie‐Weiss law was employed to study the extent of diffusivity. The effects of Y doping on morphology are investigated using scanning electron microscopy. The maximum remanence value (2Pr) and piezoelectric coefficient (d33) are 8.178 μC cm−2 and 116 pC/N respectively for x = 0.005 doping composition. A correlated behavior of optimum values is observed in density, dielectric constant, and piezoelectric coefficient which can be exploited for various applications.

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“…The two semicircular arcs observed within the studied temperature range, with their centers below the real axis, are indicative of non-Debye type relaxation. Such behavior can be correlated to various factors, such as grain orientation, grain boundaries, stress-strain phenomena and atomic defect distribution [54,55]. The semicircle at a higher frequency is ascribed to the grain (bulk) contribution and that at a lower frequency to the grain boundary contribution.…”

Section: Resultsmentioning

confidence: 99%

Influence of samarium and iron substitution on structural and electrical properties of barium zirconate titanate solid solutions

Kaur

Singh

2019

Journal of Asian Ceramic Societies

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Solid solutions of (x)SmFeO 3 -(1-x)Ba(Zr 0.05 Ti 0.95 )O 3 : x = 0, 0.21, 0.22 and 0.23 were synthesized by the solid-state reaction route. Le-Bail analysis of the X-ray diffraction data and Raman spectra revealed the presence of the tetragonal phase (P4mm space group 99). The remnant polarization (P r ) was~4.08 µC/cm 2 and 1.04 µC/cm 2 for x= 0 and x= 0.21, respectively, while lossy loops were observed for x≥ 0.22. Canting of the antiferromagnetic spins and ferromagnetic exchange mechanism was responsible for the ferromagnetic feature in the samples. An increase in remnant magnetization (M r ) was observed with increases in x. The Nyquist plots revealed the existence of grain and grain boundaries in the overall impedance. Separation of the normalized plots of impedance (Z˝) and modulus (M˝) spectra indicated localized motion of the charge carriers in the sample. The Maxwell-Wagner model fits very well in the lowfrequency region (10 5 Hz). The ac conductivity obeyed the Universal Jonscher's Power law. The variations in the exponent n suggest that the conduction mechanism conforms to the small polaron hopping mechanism.

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Effect of Yttrium Doping in Barium Zirconium Titanate Ceramics: A Structural, Impedance, and Modulus Spectroscopy Study

Cited by 26 publications

References 47 publications

Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes

Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes

Modulating the Effect of Yttrium Doping on the Structural and Dielectric Properties of Barium Titanate

Influence of samarium and iron substitution on structural and electrical properties of barium zirconate titanate solid solutions

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Effect of Yttrium Doping in Barium Zirconium Titanate Ceramics: A Structural, Impedance, and Modulus Spectroscopy Study

Cited by 26 publications

References 47 publications

Garnet-based Li6CaLa2Sb2O12:Eu3+red phosphors: a potential color-converting material for warm white light-emitting diodes

Garnet-based Li6CaLa2Sb2O12:Eu3+red phosphors: a potential color-converting material for warm white light-emitting diodes

Modulating the Effect of Yttrium Doping on the Structural and Dielectric Properties of Barium Titanate

Influence of samarium and iron substitution on structural and electrical properties of barium zirconate titanate solid solutions

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Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes

Garnet-based Li₆CaLa₂Sb₂O₁₂:Eu³⁺red phosphors: a potential color-converting material for warm white light-emitting diodes