scholarly journals Hydrogen Peroxide-Assisted Hydrothermal Synthesis of BiFeO3 Microspheres and Their Dielectric Behavior

2020 ◽  
Vol 6 (3) ◽  
pp. 42
Author(s):  
Asad Syed ◽  
Ashoka Siddaramanna ◽  
Abdallah M. Elgorban ◽  
D. A. Hakeem ◽  
G. Nagaraju
Keyword(s):  
Dielectric Constant ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Dielectric Behavior ◽  
Pure Bifeo3 ◽  
Hydrothermal Route ◽  
Conventional Solid State Reaction ◽  
Uniform Size ◽  
Powder Xrd Analysis ◽  
Scanning Electron

Despite considerable efforts undertaken in a rapidly developing area of multiferroic research, synthesis of phase pure BiFeO3 is still a matter of intensive research. In this work, we report the shape-controlled synthesis of pure BiFeO3 microspheres via a facile hydrothermal route. The prepared BiFeO3 powder has been characterized using powder X-ray Diffraction (XRD), Differential Thermal analysis (DTA), Scanning Electron microscopy (SEM), and impedance spectroscopy. Powder XRD analysis confirms the formation of pure rhombohedrally distorted perovskite with R3c space group. Scanning electron micrograph revealed that the prepared BiFeO3 microspheres are nearly spherical in shape with uniform size distribution. The BiFeO3 microspheres exhibit a dielectric constant value of ~110 at 1000 KHz, which is higher than the BiFeO3 prepared by conventional solid-state reaction and sol–gel method. Variation of dielectric constant with temperature at different frequencies shows that the BiFeO3 has a dielectric anomaly of ferroelectric to paraelectric type at 1093 K and this phenomenon is well supported by TGA results.

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

scholarly journals KARAKTERISASI KAPASITOR BARIUM STRONTIUM TITANAT (BST) Ba0,75 Sr0,25 TiO3 , YANG DIBUAT MENGGUNAKAN METODE SOL-GEL

2019 ◽  
Vol 16 (1) ◽  
pp. 65
Author(s):  
Rahmi Dewi ◽  
Tiara Pertiwi ◽  
Krisman Krisman
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Impedance Spectroscopy ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Sol Gel ◽  
Barium Strontium ◽  
Scanning Electron

The thin film of Barium Strontium Titanate (BST) has been studied withcomposition ofby using sol-gel method that annealed in temperature of 600oC and 650oC. The thin film of BST is characterized by using Field Emission Scanning Electron Microscopy (FESEM) and an impedance spectroscopy. The results of  FESEM characterization for samples in temperature of 600oC and 650oC are 55.83 nm and 84.88 nm in thickness respectively. The result of impedance spectroscopy characterization given frequency values obtained by the impedance value of real and imaginary.The capacitance value at a frequency of 20 Hz from a thin film of BST in temperature of 600oC and 650oC are 69.36Fand138.70F. The dielectric constant of the thin film of BST in temperature of 600oC and 650oC are 22.17 dan 131.56 respectively.

Facile Electrospinning Preparation of Y3Al5O12 Nanobelts

2013 ◽  
Vol 448-453 ◽  
pp. 3041-3045
Author(s):  
Fei Bi ◽  
Xiang Ting Dong ◽  
Jin Xian Wang ◽  
Gui Xia Liu ◽  
Wen Sheng Yu
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Ftir Analysis ◽  
X Ray ◽  
Novel Structure ◽  
Group I ◽  
Sol Gel Process ◽  
Composite Nanobelts ◽  
Scanning Electron

PVP/[Y(NO3)3+Al (NO3)3] composite nanobelts were fabricated via electrospinning combined with sol-gel process and novel structure of Y3Al5O12(denoted as YAG for short) nanobelts have been obtained after calcination of the relevant composite nanobelts. The structural properties were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis indicated that the composite nanobelts were amorphous, and YAG nanobelts were cubic in structure with space group Ia3d. FTIR analysis manifested that pure YAG nanobelts were formed at 900oC. SEM analysis and histograms revealed that the width of the composite nanobelts and YAG nanobelts were 3.5 μm and 2.4 μm, and the thickness were 240 nm and 112 nm, respectively, under the 95% confidence level. The formation mechanism of YAG nanobelts was discussed in detail.

scholarly journals Dielectric Properties of the System GdCo1-xFexO3Synthesized by Chemical Route (x = 0.10, 0.20)

2006 ◽  
Vol 3 (4) ◽  
pp. 313-328
Author(s):  
K. D. Mandal ◽  
L. Behera
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Chemical Method ◽  
Perovskite Oxides ◽  
Space Charge Polarization ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Chemical Route ◽  
Scanning Electron

The perovskite oxides GdCo1-xFexO3(x = 0.10, 0.20) were prepared by chemical method. The dielectric behavior of compositions with x = 0.10 and 0.20 in the system GdCo1-xFexO3was studied in the temperature range 300-500 K. It is observed that dielectric constant increases with increasing Fe2+ions concentration. The frequency dependence of dielectric constant in these materials indicates that space charge polarization contributes significantly to their observed dielectric parameters. A uniform distribution of grains is observed from the microstructure by Scanning electron microscopy.

scholarly journals Fabrication and Superhydrophobic Property of ZnO Micro/Nanocrystals via a Hydrothermal Route

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chunmei Xiao ◽  
Jing Yan ◽  
Taohai Li
Keyword(s):  
Large Scale ◽  
Hydrothermal Process ◽  
Hydrothermal Route ◽  
One Pot ◽  
Uniform Size ◽  
Water Contact ◽  
X Ray ◽  
Superhydrophobic Property ◽  
Surface Modified ◽  
Scanning Electron

Superhydrophobic ZnO micro/nanocrystals were fabricated on a large scale using a facile one-pot hydrothermal process successfully. The morphologies and chemical composition of as-synthesized ZnO were investigated by the scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The morphology of ZnO products changed from uniform size microrods to flower-like micronanostructures, when the temperature changed from 120°C to 180°C. The morphology of ZnO was strongly affected by the pH. The wettability of the as-synthesized ZnO micro/nanocrystals was studied by measuring water contact angle (CA). The largest static CA for water is 167°, which is closely related to both the ZnO micro/nanostructure and chemical modification. Furthermore, the as-prepared ZnO surface showed superhydrophobicity for some corrosive liquids such as basic and acidic aqueous solutions. The CAs of the surface modified with ZnO prepared at 160°C were over 155° in the range of pH = 1–13.

Preparation and Properties of CCTO-BCTO Ceramics with Ultrahigh Dielectric Constant

2013 ◽  
Vol 760-762 ◽  
pp. 705-708
Author(s):  
La Chen ◽  
Wei Li ◽  
Zhao Xian Xiong ◽  
Chun Xiao Song ◽  
Hong Qiu
Keyword(s):  
Electron Microscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
X Ray Diffraction ◽  
Optimum Amount ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Impedance Characteristics ◽  
Lcr Meter ◽  
Scanning Electron

Ceramics of (1-x)CaCu3Ti4O12-xBi2/3Cu3Ti4O12, i.e., CCTO-BCTO, with x=0, 0.01, 0.1 and 0.25, respectively, were prepared via the conventional solid-state reaction. The phase structure of the ceramics was identified by X-ray diffraction. The microstructure of the sample was observed with scanning electron microscopy. Dielectric properties and impedance spectroscopy were measured using a LCR Meter, in which 0.9CCTO-0.1BCTO displayed highest dielectric constant (584108) and lowest dielectric loss (0.42) at 1kHz among the four kinds of specimens. Based on series of experimental results, an optimum amount of x was able to improve the dielectric properties of CCTO-BCTO, through adjusting the impedance characteristics of the grain and grain boundary.

scholarly journals Undoped and Eu3+ Doped Magnesium-Aluminium Layered Double Hydroxides: Peculiarities of Intercalation of Organic Anions and Investigation of Luminescence Properties

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 736 ◽  
Author(s):  
Aurelija Smalenskaite ◽  
Lina Pavasaryte ◽  
Thomas Yang ◽  
Aivaras Kareiva
Keyword(s):  
Layered Double Hydroxides ◽  
Organic Anion ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Guests ◽  
Double Hydroxides ◽  
Scanning Electron

The Mg3/Al and Mg3/Al0.99Eu0.01 layered double hydroxides (LDHs) were fabricated using a sol-gel chemistry approach and intercalated with different anions through ion exchange procedure. The influence of the origin of organic anion (oxalate, laurate, malonate, succinate, tartrate, benzoate, 1,3,5-benzentricarboxylate (BTC), 4-methylbenzoate (MB), 4-dimethylaminobenzoate (DMB) and 4-biphenylacetonate (BPhAc)) on the evolution of the chemical composition of the inorganic-organic LDHs system has been investigated. The obtained results indicated that the type and arrangement of organic guests between layers of the LDHs influence Eu3+ luminescence in the synthesized different hybrid inorganic–organic matrixes. For the characterization of synthesis products X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS), and scanning electron microscopy (SEM), were used.

Investigation of Low Temperature Sintering of Low Voltage Varistor Based on TiO2

2014 ◽  
Vol 852 ◽  
pp. 12-16 ◽  
Author(s):  
De Jun Lan ◽  
Shu Quan Wan
Keyword(s):  
Dielectric Constant ◽  
Low Temperature ◽  
Room Temperature ◽  
Low Voltage ◽  
Structural Characteristics ◽  
Nonlinear Coefficient ◽  
Xrd Analysis ◽  
Low Temperature Sintering ◽  
Powder Xrd Analysis ◽  
Room Temperature Dielectric Constant

Low temperature sintering of TiO2-base varistor was systematically investigated through doing with V2O5 and B-Si glass. Pellets prepared could be densely sintered from 1273 to 1473K. The highest relative density, 94.6%, was found in the sample sintered at 1433K. According to I-V plots of ceramic pellets, the nonlinear coefficient α and breakdown voltage V1mA were obtained and found to be α=2~5 and V1mA=15~30V. The room temperature dielectric constant was very large, high as to about 20000. Powder XRD analysis has shown the desirable macro-structural characteristics of these compacts.

Effect of CaO Dopant on the Dielectric Properties of NiO

2013 ◽  
Vol 789 ◽  
pp. 138-142
Author(s):  
Sharifah Aishah Syed Salim ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad
Keyword(s):  
Electron Microscopy ◽  
Dielectric Constant ◽  
Phase Identification ◽  
Dielectric Analysis ◽  
Frequency Range ◽  
Conventional Solid State Reaction ◽  
Impedance Analyzer ◽  
Microstructural Observation ◽  
Ca Ions ◽  
Scanning Electron

CaxNi1-xO was prepared by conventional solid state reaction. The properties of undoped and CaO doped NiO ceramics have been studied. The raw mixture of CaO and NiO were ball milled for 24 hours. The samples were calcined at 1000°C for 2 hours, pressed into pellet shape at 200 MPa and sintered at 1300°C for 4 hours. The sintered samples were subjected to XRD, Scanning Electron Microscopy (SEM) and Impedance Analyzer for phase identification, microstructural observation and dielectric analysis. The grains size becomes larger with the increment of dopant amount. Enhanced dielectric constant was observed for all Ca doped NiO at the frequency range from 100 Hz to 1 MHz. The dielectric constant of sintered CaxNi1-xO decreased with an increasing frequency. The result indicates that Ca ions have effectively changed the properties of NiO.

A Study on the Preparation of Nano-Crystalline Barium Titanate Powder by a Sol-Gel Method

2007 ◽  
Vol 121-123 ◽  
pp. 53-56 ◽  
Author(s):  
J. Azadmanjiri ◽  
Hojjatollah K. Salehani ◽  
A. Dehghan Hamedan ◽  
M. Sadeghi
Keyword(s):  
Crystallite Size ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
Impedance Analyzer ◽  
X Ray ◽  
Nano Crystalline ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Scanning Electron

In this work, high purity BaTiO3 (BT) nano-powders by a sol-gel process was prepared with Ba(NO3)2 and Ti(C4H9O)4 materials in order to acquire uniform size grains. The effects of the crystallinity, microstructure of BT nano-powders calcined at different temperatures and dielectric properties of the ceramics were investigated by XRD, SEM and impedance analyzer, respectively. Scanning electron microscopy and X-ray diffraction investigation revealed cubic plates and crystallite size. The results revealed that crystallite size and calcination temperature of BT and influence on the dielectric constant.

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