Electrical Properties of the Mixed Bismuth Layer-Structured Bi7Ti4NbO21 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 255-258 ◽  
Author(s):  
Lina Zhang ◽  
Guo Rong Li ◽  
Su Chuan Zhao ◽  
Liao Ying Zheng ◽  
Qing Rui Yin
Keyword(s):  
Remanent Polarization ◽  
Piezoelectric Coefficient ◽  
Hysteresis Loops ◽  
Test System ◽  
Orthorhombic Symmetry ◽  
Thermal Dependence ◽  
Paraelectric Phase Transition ◽  
Two Phase ◽  
Conventional Solid State Reaction ◽  
X Ray

A mixed bismuth layer-structured compound, Bi7Ti4NbO21, has been prepared by the conventional solid state reaction. It showed an orthorhombic symmetry with a = 5.4428, b = 5.4043 and c = 29.041 Å by X-ray powder diffraction analysis. The hysteresis loops as a function of temperature were observed with a standardized ferroelectric test system. The remanent polarization and the coercive field of the material at 140°C were 14.06 µC/cm2 and 78.6 kV/cm, respectively. Thermal dependence of dielectric permittivity showed two-phase transitions at around 670°C and 845°C, which were also investigated by TSC and DSC. Finally, piezoelectric properties were obtained with a piezoelectric coefficient d33 = 10 pC/N. It was observed that Bi7Ti4NbO21 underwent a ferroelectric–paraelectric phase transition at 845°C by depolarization experiments.

Synthesis of Modified K0.5Na0.5NbO3 Powder by Molten-Salt Technique

2017 ◽  
Vol 728 ◽  
pp. 160-165
Author(s):  
Thanatep Phatungthane ◽  
Buagun Samran ◽  
Gobwute Rujijanagul
Keyword(s):  
Molten Salt ◽  
Calcination Temperature ◽  
Perovskite Phase ◽  
Orthorhombic Symmetry ◽  
Molten Salt Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Fine Grain ◽  
Pure Perovskite Phase

In the present work, the molten-salt method was applied to synthesize 0.948K0.5Na0.5NbO3–0.052LiSbO3 powder for the first time. Characteristics of the powder were investigated. Based on X-ray diffraction technique, pure perovskite phase was observed at a calcination temperature of 700 oC which is lower than that required by the conventional solid-state reaction technique for ∼200 oC. Raman spectroscopy technique showed that the powder had an orthorhombic symmetry which consistent with the X-ray diffraction results. The powder exhibited very fine grain with narrow size distribution. Particle size of the obtained powders increased with increasing calcination temperature. Therefore, the molten-salt method is a simple and effective method to synthesize 0.948K0.5Na0.5NbO3 – 0.052LiSbO3 powder.

Influence of Bi-site Substitution on the Ferroelectricity of the Aurivillius Compound Bi2SrNb2O9

1998 ◽  
Vol 13 (9) ◽  
pp. 2565-2571 ◽  
Author(s):  
P. Durán-Martín- ◽  
A. Castro ◽  
P. Millán ◽  
B. Jiménez
Keyword(s):  
Dielectric Constant ◽  
Electric Conductivity ◽  
Remanent Polarization ◽  
Hysteresis Loops ◽  
Relaxor Behavior ◽  
Paraelectric Phase Transition ◽  
Thermally Activated ◽  
Coupling Factors ◽  
Higher Temperature ◽  
First Time

Ceramics based on the composition Bi2SrNb2O9 with isomorphic substitutions of cations in the Bi2O22+ and the perovskite layers, Bi2−xTexSr1−xNa(K)xNb2O9, have been prepared by solid state reaction. The ferroelectricity of this Aurivillius type structure has been studied. Dielectric measurements as a function of the temperature show a low temperature maximum in the dielectric constant that would correspond to a ferro-;paraelectric phase transition. The temperature of this maximum increases when the radius of the ion that substitutes Sr for decreases. A second maximum in the dielectric constant is found at higher temperature possibly corresponding to a relaxor ferroelectric. Measurements of remanent polarization as a function of the temperature seem to confirm the relaxor behavior, because the polarization disappears at temperatures between the two maxima of the dielectric constant. Saturated hysteresis loops are obtained for all the substituted samples at temperatures above 300 °C. Ferroelectric parameters such as the polarization, coercive field, and coupling factors of the BSN family compounds were obtained for the first time. The ac electric conductivity shows anomalies at temperatures close to those where the remanent polarization disappears. Activation energies calculated from measurements of dc electric conductivity, impedance arcs, and dielectric modulus data may be associated with thermally activated oxygen vacancies.

scholarly journals Critical temperature below the Curie temperature of ferroelectric ceramics PZT

2021 ◽  
pp. 2150006
Author(s):  
D. V. Kuzenko
Keyword(s):  
Critical Temperature ◽  
Curie Temperature ◽  
Lead Zirconate Titanate ◽  
Remanent Polarization ◽  
Lead Zirconate ◽  
Ferroelectric Ceramics ◽  
Paraelectric Phase Transition ◽  
X Ray ◽  
Temperature Range ◽  
Temperature Dependences

The article presents the results of research the pre-transitional features of the behavior of solid solutions based on lead zirconate-titanate. The presence of a “special” critical temperature [Formula: see text] on the temperature dependences of the permittivity [Formula: see text] and the remanent polarization [Formula: see text], preceding the temperature of the paraelectric phase transition at the Curie temperature [Formula: see text], is noted. In the temperature range [Formula: see text], the [Formula: see text] dependence obeys a power law. In the temperature range [Formula: see text], this law is not fulfilled. The results of X-ray experiments make it possible to associate this behavior with reversible disordering at [Formula: see text] of an ordered domain structure formed during the polarization of piezoelectric ceramics and with its irreversible disordering in the temperature range [Formula: see text]. This is due to the appearance of internal mechanical stresses in a polycrystalline ferroelectric due to irreversible depolarization of the samples at temperatures [Formula: see text].

Rietveld refinement X-ray powder data of Pr0.7Ba0.3MnO3

2003 ◽  
Vol 18 (1) ◽  
pp. 29-31
Author(s):  
M. Ellouze ◽  
W. Boujelben ◽  
H. Fuess
Keyword(s):  
Solid State ◽  
Rietveld Refinement ◽  
Solid State Reaction ◽  
Rietveld Method ◽  
Xrd Analysis ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Space Group ◽  
X Ray

Powder X-ray diffraction (XRD) data were collected for Pr0.7Ba0.3MnO3. This sample was prepared using the conventional solid state reaction by mixing Pr6O11, Mn2O3, and BaCO3 up to 99.9% purity at 1400 °C in air for 60 h. XRD analysis using the Rietveld method was carried out and it was found that this manganite sample has orthorhombic symmetry with Pnma space group. The lattice parameters are found to be a=5.4900 Å, b=7.7578 Å, and c=5.5227 Å.

Effects of B2O3 doping on the dielectric and piezoelectric properties of (K,Na,Li)NbO3-BaZrO3-(Bi,Na)TiO3 ceramics

2021 ◽  
Author(s):  
Nan Wei ◽  
Tomoaki KARAKI ◽  
Tadashi Fujii
Keyword(s):  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
X Ray ◽  
High Relative Density ◽  
Dielectric And Piezoelectric Properties

Abstract (K,Na,Li)NbO3-BaZrO3-(Bi,Na)TiO3-x B2O3 (abbreviated as KNLN-BZ-BNT-x B2O3) ceramics were prepared by conventional solid state reaction method. The effects of B2O3 content on dielectric and piezoelectric properties of the KNLN-BZ-BNT ceramics have been studied. Based on the identification by X-ray diffraction (XRD), all the samples show a two-phase coexistence zone consisting of rhombohedral (R) and tetragonal (T) phases. For the ceramics with x = 0.5 wt%, the sintering temperature was observed to reduce from 1200 oC to 940 oC, while the samples maintained a high relative density around 97%. Because of the high densification and large grain size, the dielectric and piezoelectric properties were improved. As a result, the ceramics with x = 0.5 wt% sintered at 940 oC exhibited good properties of d 33 = 197 pC/N, k p= 0.29, tan δ = 0.029 and ε r = 1889, together with a Curie temperature (T C) of 222 oC.

Measurements of Polarization Switching in LiNbO3-type ZnSnO3/ZnO Nanocomposite Thin Films

2015 ◽  
Vol 1729 ◽  
pp. 111-116 ◽  
Author(s):  
Devajyoti Mukherjee ◽  
Mahesh Hordagoda ◽  
Corisa Kons ◽  
Anuja Datta ◽  
Sarath Witanachchi ◽  
...  
Keyword(s):  
Remanent Polarization ◽  
Hysteresis Loops ◽  
Polarization Switching ◽  
Nanocomposite Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polarization Measurements ◽  
Si Substrates ◽  
Nanocomposite Thin Films ◽  
Free Material

ABSTRACTWe report the measurements of ferroelectricity in LiNbO3 (LN)-type ZnSnO3 /ZnO nanocomposite thick films deposited on Pt-Si substrates using a novel combined chemical/physical technique. Phase-pure LN-type ZnSnO3 nanorods (NRs) were first synthesized using a low temperature solvothermal process and characterized in detail using X-ray diffraction, electron microscopy and Raman spectroscopy. The prototype device for polarization measurements was fabricated by depositing the as-prepared LN-type ZnSnO3 NRs onto conducting Pt-Si substrates (also served as bottom electrodes). A dielectric filler-layer of polycrystalline ZnO was deposited on top using pulsed laser deposition to fabricate LN-type ZnSnO3 /ZnO nanocomposite films. Polarization measurements of the Pt/ZnSnO3+ZnO/Pt nanocomposite capacitors at 300K showed indication of polarization switching in the hysteresis loops with a remanent polarization (Pr) of 13 μC/cm2 at a low applied voltage of 8 V. The work provides information on the coherent design of future FE memory devices based on the emerging non-toxic Pb-free material LN-ZnSnO3.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

scholarly journals Revisiting the Bøggild Intergrowth in Iridescent Labradorite Feldspars: Ordering, Kinetics, and Phase Equilibria

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Shiyun Jin ◽  
Huifang Xu ◽  
Seungyeol Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Phase Region ◽  
Two Phase ◽  
Subsolidus Phase ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The enigmatic Bøggild intergrowth in iridescent labradorite crystals was revisited in light of recent work on the incommensurately modulated structures in the intermediated plagioclase. Five igneous samples and one metamorphic labradorite sample with various compositions and lamellar thicknesses were studied in this paper. The lamellar textures were characterized with conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The compositions of individual lamellae were analyzed with high-resolution energy-dispersive X-ray spectroscopy (EDS) mapping and atom probe tomography (APT). The average structure states of the studied samples were also compared with single-crystal X-ray diffraction data (SC-XRD). The Na-rich lamellae have a composition of An44–48, and the Ca-rich lamellae range from An56 to An63. Significant differences between the lamellar compositions of different samples were observed. The compositions of the Bøggild intergrowth do not only depend on the bulk compositions, but also on the thermal history of the host rock. The implications on the subsolidus phase relationships of the plagioclase feldspar solid solution are discussed. The results cannot be explained by a regular symmetrical solvus such as the Bøggild gap, but they support an inclined two-phase region that closes at low temperature.

scholarly journals Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3790
Author(s):  
Yongzheng Ji ◽  
Tsuyoshi Honma ◽  
Takayuki Komatsu
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Ion Conductivity ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Time ◽  
Lower Activation

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

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