DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF LEAD-FREE (Bi0.5Na0.5)0.94Ba0.06TiO3 + x%Ce2O3 + y%La2O3 + z%Y2O3 COMPOUNDS SYNTHESIZED BY SOL–GEL TECHNIQUE

2012 ◽  
Vol 02 (04) ◽  
pp. 1250022
Author(s):  
A. CHAOUCHI ◽  
M. SAIDI ◽  
S. D'ASTORG ◽  
M. RGUITI ◽  
C. COURTOIS
Keyword(s):  
Remanent Polarization ◽  
Piezoelectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric ◽  
Gel Technique ◽  
Tan Δ ◽  
High Dielectric ◽  
Dielectric And Piezoelectric Properties

( Bi 0.5 Na 0.5)0.94 Ba 0.06 TiO 3 + x% Ce 2 O 3 + y% La 2 O 3 + z% Y 2 O 3 compounds (named BNT–BT– x/y/z) were synthesized by a sol–gel technique, for (x,y,z) = (0,0,0), (0.25, 0.25, 0.25), (0.25, 0.5, 0.5), (0.5, 0.25, 0.25) and (0.5, 0.5, 0.25). The structural variation according to the different system compositions is investigated by X-ray diffraction analyses. The results shows that the addition of Ce2O3 , La2O3 or Y2O3 in BNT–BT system, do not modify the crystalline structure, and a rhombohedral–tetragonal morphotropic phase boundary is maintained for different dopant addition. The BNT–BT–x/y/z-based ceramics sintered at relatively low temperature (1100°C) exhibit a good densification ratio. The optimum dielectric and piezoelectric properties are obtained with the BNT–BT–0.5/0.25/0.25 composition. High dielectric properties at room temperature (εr > 1000) and low dielectric losses (tan δ < 4 × 10-2) are obtained for this composition. This compound exhibits a piezoelectric constant d33 of 95 pC/N, a good polarization behavior is observed with high remanent polarization Pr of 9.21 μC/cm2 and low value coercitive field Ec of 2.66 kV/mm.

Combinatorial Laser Processing Of Dielectric/Ferroelectric Thin and Thick Films

2002 ◽  
Vol 748 ◽  
Author(s):  
R. N. Das ◽  
C. Lew ◽  
I. Zergioti ◽  
M. O. Thompson ◽  
E. P. Giannelis
Keyword(s):  
Thin Films ◽  
Thermal Annealing ◽  
Laser Processing ◽  
Thick Films ◽  
Sol Gel ◽  
Phase Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric ◽  
High Dielectric

ABSTRACTA library of different crystalline sol-gel thin films with a composition of BaxTiyOz (where x = 1,2; y = 1,2,9 and z = 3, 7, 20) has been generated using variable multi-step laser and thermal annealing. Point by point X-ray diffraction characterization revealed the presence of high dielectric (BaTiO3) and low dielectric (Ba2Ti2O7 and Ba2Ti9O20) phases. Appropriate laser and thermal annealing controlled crystallinity, phase content, morphology and dielectric property of libraries. We have extended the process to BaTiO3 based thick-films and investigated the surface morphology of laser-annealed films.

Structural Characterization for Ceramic Pyrochlores of Bi-Zn-Nb-O

2018 ◽  
Vol 912 ◽  
pp. 16-20 ◽  
Author(s):  
Francisco Werley Cipriano Farias ◽  
Antonio Sidnel Gomes Alves ◽  
Yuri Mikael dos Santos Alves ◽  
Francisca Maria Martins Pereira ◽  
Maria das Dores Bandeira Barroso ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Ceramic Method ◽  
X Ray ◽  
Low Dielectric ◽  
Α Phase ◽  
Refinement Method ◽  
Tan Δ ◽  
High Dielectric

Ceramic pyrochlores, the basis of Bi2O3-ZnO-Nb2O5 (BZN), have dielectric properties of great interest, such a high dielectric constant (ε), a low dielectric loss tangent (tan δ) and a low coefficient of capacitance with temperature (TCC). The system has two main phases, Bi1,5ZnNb1,5O7 (α) and Bi2Zn0,67Nb1,33O7 (β) with cubic and orthorhombic crystal structures, and very different dielectric properties. The purpose of this article was to synthesize chemically homogeneous ceramic pyrochlores BZN-α and BZN-β, using the ceramic method in obtaining nanopowders and their characterizations by scanning electron microscopy (SEM), X-Ray Diffraction (XRD), and the Rietveld refinement method of the structures. The powders were weighed in stoichiometric proportions and calcined at 700 °C/2h, they were sintered at 900, 950 and 1000 °C/2h. A pure BZN-α phase was obtained, while the BZN-β has remained in phases as Bi5Nb3O15 and BiNbO4.

scholarly journals Calcination Effect on Structural Trasformation of Barium Titanite Ferroelectric Ceramic by Sol-Gel Method

2019 ◽  
Vol 9 (1) ◽  
pp. 5893-5896
Keyword(s):  
Glacial Acetic Acid ◽  
Sol Gel ◽  
Ferroelectric Ceramic ◽  
Tetrabutyl Titanate ◽  
Chemical Modifier ◽  
Barium Acetate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Scanning Electron

High purity barium titanate BaTiO3 was successfully synthesized by using the sol-gel technique. Barium acetate Ba(CH3COO)2 and tetrabutyl titanate, Ti(C4H9O)4 was dissolved moderately in the solvent of glacial acetic acid and ethanol was added as the chemical modifier. The synthesized BaTiO3 nanoparticle was calcined at the temperature range of 700 ºC to 1100 ºC. The powders were further characterized by X-ray diffraction and scanning electron microscopy (SEM). Fined BaTiO3 powders result indicates the phase of tetragonal structures and high crystallites of BaTiO3. It was observed that the crystallinity and particle size of BaTiO3 is greatly influenced by the calcination temperature.

scholarly journals Synthesis Photocatalytic and Antibacterial Activities of Nickle Doped Tio2 Nanoparticles

2018 ◽  
Vol 34 (6) ◽  
pp. 3140-3144
Author(s):  
Ritu Vershney ◽  
Komal Chelaramani ◽  
Arpan Bhardwaj ◽  
Nayma Siddiqui ◽  
Suresh Kumar Verma
Keyword(s):  
Photocatalytic Degradation ◽  
Tio2 Nanoparticles ◽  
Sol Gel ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
Zone Of Inhibition ◽  
Time Duration ◽  
X Ray ◽  
Gel Technique ◽  
Doped Titania

The synthesis of Ni doped titania (TiO2) nanoparticles were achieved via simple novel sol gel technique, in which Titanium-n-butoxide and NiCl2 were taken as precursors. Effect of different wt% of dopant in TiO2 was studied on photocatalytic degradation of Aniline blue and Toluidine Blue. The study suggested the increased photocatalytic degradation with increased time duration. The synthesized samples were analyzed by surface electron microscopy (SEM) and X-ray diffraction studies. The antibacterial activity was investigated against Gram-positive Staphylococcus aureus bacteriae. Studies revealed that on increasing the dopant concentration, the diameter of zone of inhibition also increased upto 1.5 wt%.

Fabrication of Porous LSCF-SDC Carbonates Composite Cathode for Solid Oxide Fuel Cell (SOFC) Applications

2011 ◽  
Vol 471-472 ◽  
pp. 179-184 ◽  
Author(s):  
Raharjo Jarot ◽  
Andanastuti Muchtar ◽  
Wan Ramli Wan Daud ◽  
Norhamidi Muhamad ◽  
Edy Herianto Majlan
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Composite Cathode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Composite Cathodes ◽  
Gel Technique ◽  
Optimum Porosity ◽  
Cold Pressed

Composite cathodes made of perovskite La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and SDC carbonates (SDC-(Li/Na)2CO3) were investigated in relation to their structure, morphology, thermal expansion coefficient and porosity. As a first step, the LSCF powder was prepared by sol-gel technique. This was followed by the preparation of the LSCF-SDC carbonates composite cathode by mixing the LSCF with SDC-(Li/Na)2CO3 electrolyte via solid state reaction in various compositions, i.e. 30, 40 and 50 wt.%, namely 70LSCF-30SDC7030, 60LSCF-40SDC7030 and 50LSCF-50SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 3.39-7.42 m2/g and particle size of 0.56-0.66µm. The powder consists of two distinct phases, i.e. LSCF and SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). Increasing the amount of the SDC-(Li/Na)2CO3 electrolyte in the composite cathode was found to bring the thermal expansion of the cathode closer to that of the electrolyte. The cathode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.98%) was achieved for samples with SDC-(Li/Na)2CO3 content of 30-50% sintered at 600oC and cold pressed at 37 MPa.

Effects of Barium Substitution on the Structure and Properties of PSZT Piezoelectric Ceramics

2010 ◽  
Vol 650 ◽  
pp. 103-108
Author(s):  
Yu Hua Feng ◽  
Tie Zheng Pan ◽  
Xiang Qian Shen ◽  
Hao Jie Song ◽  
Li Ping Guo
Keyword(s):  
Curie Temperature ◽  
Structural Changes ◽  
Piezoelectric Properties ◽  
Relative Dielectric Constant ◽  
Piezoelectric Ceramics ◽  
X Ray Diffraction ◽  
Piezoelectric Strain ◽  
High Dielectric ◽  
Dielectric And Piezoelectric Properties ◽  
Piezoelectric Strain Constant

Piezoelectric ceramics with appropriate curie temperatures and high dielectric and piezoelectric performances are attractive for formations of ceramic/polymer piezoelectric composites. The PSZT ceramics with compositions of 0.98Pb1.0-xBaxTi0.48Zr0.52O3-0.02PbSbO3 (x=0.14~0.24) have been prepared by a conventional solid reaction process. The ceramic structures are analyzed by X-ray diffraction and the barium substitution leads to structural changes of the tetragonal and rhombohedral phases which constitute the perovskite PSZT ceramics, and lattice distortions. The curie temperature almost linearly decreases from 226 °C to 141 °C corresponding the barium content increases from 0.14 to 0.24 in the ceramics. The dielectric and piezoelectric properties are largely influenced by the barium substitution and when the barium content at vicinity of 0.22, the piezoelectric strain constant d33 exhibits a dramatic change. It is found that as the barium content around 0.22, the PSZT ceramic specimen is characterized with a low curie temperature Tc=156 °C, and satisfied dielectric and piezoelectric properties with the relative dielectric constant εr=5873, dielectric loss factor tanδ=0.0387, piezoelectric strain constant d33=578 pC/N.

Ferroelectric PTCR Films for Photonic Crystal Gas Sensor

2006 ◽  
Vol 952 ◽  
Author(s):  
J. RaviPrakash ◽  
Susan Trolier-McKinstry ◽  
Jing-Gong Cheng ◽  
Mark McNeal ◽  
Anton Greenwald ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Electric Fields ◽  
Remanent Polarization ◽  
Sol Gel ◽  
Mems Devices ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ptcr Effect ◽  
La Doped ◽  
Room Temperature Dielectric Constant

ABSTRACTWe examined lanthanum doped lead barium titanate films for temperature measurements of photonic crystal - MEMS devices. Films were deposited by sol-gel techniques and crystallized in air above 650°C. X-ray diffraction spectra consistent with the perovskite structure were detected. The room temperature dielectric constant was ∼570 at 10 kHz of La-doped (0.3 mol%) Pb0.3Ba0.7TiO3 films. These films had a remanent polarization of ∼20μC/cm2 and a coercive field of 145 kV/cm. The leakage current density was ∼ 2×10−7 amps/cm2 at 100 kV/cm field. The resistivity of the films extracted from the linear region of the I-V data (electric fields in excess of 100 kV/cm) measured as a function of temperature shows an increase in resistivity at temperatures above Tc (120°C for BaTiO3 and 240°C for Pb0.3Ba0.7TiO3) of the film consistent with positive coefficient of resistance (PTCR) effect. However, the change in resistance was small when compared to bulk samples of similar compositions.

scholarly journals Effect of TeO2 addition on the dielectric properties of CaCu3Ti4O12 ceramics derived from the oxalate precursor route

2013 ◽  
Vol 03 (04) ◽  
pp. 1350028 ◽  
Author(s):  
P. Thomas ◽  
K. B. R. Varma
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Practical Applications ◽  
Low Dielectric ◽  
Precursor Route ◽  
Tan Δ

CaCu 3 Ti 4 O 12 (CCTO) ceramics which has perovskite structure gained considerable attention due to its giant permittivity. But it has high tan δ (0.1 at 1 kHz) at room temperature, which needs to be minimized to the level of practical applications. Hence, TeO 2 which is a good glass former has been deliberately added to CCTO nanoceramic (derived from the oxalate precursor route) to explore the possibility of reducing the dielectric loss while maintaining the high permittivity. The structural, morphological and dielectric properties of the pure CCTO and TeO 2 added ceramics were studied using X-ray diffraction, Scanning Electron Microscope along with Energy Dispersive X-ray Analysis (EDX), spectroscopy and Impedance analyzer. For the 2.0 wt.% TeO 2 added ceramics, there is a remarkable difference in the microstructural features as compared to that of pure CCTO ceramics. This sample exhibited permittivity values as high as 7387 at 10 KHz and low dielectric loss value of 0.037 at 10 kHz, which can be exploited for the high frequency capacitors application.

Microstructure and Electrical Properties of Lead-Free (Na0.5K0.5)NbO3 - Bi0.5(Na0.97K0.03)0.5TiO3 Ceramics

2013 ◽  
Vol 368-370 ◽  
pp. 760-763
Author(s):  
Chun Huy Wang ◽  
Ming Qiu Wei
Keyword(s):  
Electrical Properties ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dense Microstructure ◽  
Dielectric And Piezoelectric Properties ◽  
Thickness Mode

(Na0.5K0.5)NbO3 with Bi0.5(Na0.97K0.03)0.5TiO3 with x≤0.05 has been prepared by the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all the Bi(Na0.97K0.03)TiO3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution with a perovskite structure. A morphotropic phase boundary (MPB) between orthorhombic (O) and rhombohedral (R) was found at the composition 0.98(Na0.5K0.5)NbO3-0.02Bi0.5(Na0.97K0.03)0.5TiO3 [abbreviated as 0.98NKN-0.02BNKT] with correspondingly enhanced dielectric and piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.33 and 0.49, respectively, after sintering at 1100 oC for 3 h. The ratio of the thickness coupling coefficient to the planar coupling coefficient is 1.48. With suitable Bi0.5(Na0.97K0.03)0.5TiO3 concentration, a dense microstructure and good electrical properties are obtained.

Thick PLZT Films Grown by Sol-gel for Optical Device Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
M. Linnik ◽  
O. Wilson ◽  
A. Christou
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Phase Modulator ◽  
X Ray Diffraction ◽  
X Ray ◽  
Device Applications ◽  
Gel Technique ◽  
Scanning Electron

AbstractThe preparation and characterization of thick PLZT films for spatial phase modulator applications are reported. Films were fabricated on LSCO/LAO substrates by a sol-gel technique using multiple heat-treatment parameters. The crystal quality of PLZT 9/65/35 films was investigated by X-ray diffraction and scanning electron microscopy.

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