scholarly journals Lattice strain driven dielectric insulation response of Sr1−xCaxBi2Nb2O9 ceramics

2016 ◽  
Vol 06 (03) ◽  
pp. 1650021
Author(s):  
Vaibhav Shrivastava
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Frequency ◽  
Room Temperature ◽  
Lattice Strain ◽  
Calcium Content ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Dielectric Insulation ◽  
Room Temperature Dielectric Constant

In this paper, effects of lattice strain on dielectric properties of Sr[Formula: see text]CaxBi2Nb2O9 ([Formula: see text]–0.5 in steps of 0.1) ceramics are reported. High frequency dipolar polarization is observed to increase for 10% calcium addition and suppresses thereafter on higher calcium concentrations. The dielectric loss values for all doped samples were lower compared to undoped one at frequencies beyond 1[Formula: see text]kHz. The sample with [Formula: see text] shows room temperature dielectric constant in the range (130[Formula: see text][Formula: see text][Formula: see text]12) over a wide frequency range from 50[Formula: see text]Hz to 1[Formula: see text]MHz also minimum dielectric loss among all other sample for the same frequency range. Remarkable increase in Curie temperature ([Formula: see text]) by 50[Formula: see text]C is recorded in the present work by increasing 10% calcium content in SBN compostion. All higher doped samples indicate increase in [Formula: see text] by further higher amount. In addition, dc conductivity of all samples is measured for all samples and increase in calcium content is observed to generate more insulating compositions compared to undoped SBN with higher intrinsic activation energies.

High Frequency Dielectric Response of the Ionic Liquid N-Methyl-N-ethylpyrrolidinium Dicyanamide

2007 ◽  
Vol 60 (1) ◽  
pp. 6 ◽  
Author(s):  
Simon Schrödle ◽  
Gary Annat ◽  
Douglas R. MacFarlane ◽  
Maria Forsyth ◽  
Richard Buchner ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
High Frequency ◽  
Dielectric Response ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Dielectric Relaxation Spectroscopy ◽  
Frequency Range ◽  
Fast Rotation

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.

Dielectric Properties of Sintered AIN

1989 ◽  
Vol 167 ◽  
Author(s):  
R. D. Harris ◽  
R. C. Enck ◽  
J. L. Fields
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Dc Resistivity ◽  
Thermally Activated ◽  
Exponential Factors ◽  
Ac Electrical Properties ◽  
Different Sources ◽  
Room Temperature Dielectric Constant ◽  
Product Literature

AbstractWe have initiated a study of the ac electrical properties (dielectric constant and dielectric loss) and the dc resistivity of sintered AIN. For this study, we have used samples purchased commercially as well as samples made by the Carborundum Company, a member of the BP Group. Variations are observed in the room temperature dielectric constant for AIN substrates obtained from different sources. The source-to-source range is from 8.5 to 8.7. This range is lower than the 8.8 to 9.2 that is generally reported in the product literature. Similar source-tosource variations in the room temperature dielectric loss are observed. All of the samples show thermally activated behavior in the dc resistivity. The activation energy observed for all of the samples is similar, EA ∼0.47 eV; however, different pre-exponential factors are apparent. As a result, there are large variations in the measured room temperature resistivities for samples from different sources.

Solid State Sintering and Microstructural Evolution on Wide Frequency Range Dielectric Responses of Mechanically Activated CaTiO3 Ceramics

2015 ◽  
Vol 1107 ◽  
pp. 38-44
Author(s):  
Wong Yick Jeng ◽  
Hassan Jumiah ◽  
Mansor Hashim
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sintering Temperature ◽  
Microstructural Analysis ◽  
High Energy ◽  
Wide Frequency Range ◽  
Milling Process ◽  
Frequency Range ◽  
Wide Range

The CaTiO3samples were prepared by high-energy ball milling process followed by sintering process from 1040 to 1200°C. X-ray diffraction (XRD), microstructural analysis, and dielectric properties over a wide range of frequency varying from 0.01 Hz to 1 GHz at room temperature were investigated. The formation of a single phase CaTiO3with orthorhombic structure was achieved at 1120°C and above. From a morphological point of view, sintering temperature promoted grain growth. Dielectric properties in the frequency range 0.01 Hz - 1 MHz revealed a relaxation-type process. Interfacial phenomena were the possible physical mechanisms that gave rise to these relaxation-type plots. Extending the frequencies above ~1 MHz yielded a frequency-independent characteristic of dielectric constant (ε'). These turned out to the relatively small dielectric loss (tan δ) values. The origin of the dielectric responses in the frequency range 1 MHz - 1 GHz was attributed to the domination of dipolar polarization. The grain size effect in sintered CaTiO3samples was prominent, notably in dielectric responses above ~1 MHz. Increase in sintering temperature remarkably led to an enhancement in dielectric constant values and reduction in dielectric loss values. Therefore, a significant correlation existed between microstructural features and dielectric properties.

Dielectric Properties of PMN/CB/CIIR Composites

2009 ◽  
Vol 66 ◽  
pp. 234-237 ◽  
Author(s):  
Hao Yan ◽  
Zhi Xiong Huang ◽  
Yan Bing Wang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Carbon Black ◽  
Lead Titanate ◽  
High Frequency ◽  
Dielectric Constants ◽  
Frequency Range ◽  
Magnesium Niobate ◽  
Chlorobutyl Rubber

The Magnesium Niobate-Lead Titanate (PMN) / conductive carbon black (CB)/ chlorobutyl rubber(CIIR) composites were prepared by blending-vulcanization method, and the dielectric properties were studied. The results showed that the dielectric constant and dielectric loss of composites increased nonlinearly when increasing the content of PMN or CB. From the curve of dielectric constant vs frequency, it is obtained that in the frequency range from 103 to 106 Hz, the dielectric constant of PMN/CB/CIIR composites decreased with the frequency increasing and the dielectric constants are more stable under high frequency.

Characterization and dielectric properties of sodium fluoride doped talc

Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Firing Temperature ◽  
Room Temperature ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Detailed Characterization ◽  
Circuit Element

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.

Dielectric Properties of Na2O Doped Cao-B2O3-SiO2 System Glass-Ceramics

2013 ◽  
Vol 750-752 ◽  
pp. 492-496
Author(s):  
Peng Fei Wei
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sintering Temperature ◽  
Glass Ceramics ◽  
Wide Frequency Range ◽  
Microwave Properties ◽  
Low Dielectric Constant ◽  
Frequency Range ◽  
Low Dielectric

The behavior of dielectric and microwave properties against sintering temperature was been carried out on CaO-B2O3-SiO2glass-ceramics with Na2O addition by XRD and SEM. The results show that 0.5 wt.% Na2O addition is advantageous to improve the dielectric and microwave properties due to increasing the major crystalline CaSiO3. With further increasing Na2O content, α-SiO2is the predominant crystalline phase instead of CaSiO3. The CBS glass-ceramics with 0.5 wt.% Na2O sintered at 875°C has a bulk density of 2.51g·cm-3, and which possesses good dielectric properties:εr=6.2,tanδ=1.9×10-3(10 MHz) and low dielectric constant below 2×10-3over a wide frequency range. The proposed dielectrics can find applications in microwave devices, which require low dielectric loss and low dielectric constant.

Thermally stabilized bismaleimide–triazine resin composites for 10-GHz level high-frequency application

2017 ◽  
Vol 30 (7) ◽  
pp. 833-839 ◽  
Author(s):  
Jie Yang ◽  
Xin Mao ◽  
Lirong Du ◽  
Bo Wu ◽  
Fangfang Zhang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Frequency ◽  
Decomposition Temperature ◽  
Resin Composites ◽  
Frequency Range ◽  
Initial Decomposition Temperature ◽  
Curing Reaction ◽  
High Frequency Application ◽  
The Stability

A hybrid cured resin with excellent dielectric and thermal properties was prepared with bismaleimide–triazine (BT) resin modified with 2,2′-diallylbisphenol A (DBA). The thermal and dielectric properties of the resin were investigated, and the effect of DBA concentration on the curing reaction was determined. Results indicated that DBA significantly influenced the curing reaction and the properties of the cured product. The modified BT resins exhibited outstanding thermal stability (initial decomposition temperature was over 400°C), although the stability was slightly lower than that of pure BT resins. The dielectric constant and dielectric loss of the cured resin decreased when DBA was introduced into the BT resins. Moreover, the fabricated resins showed dielectric constant of 2.91–3.07 and dielectric loss lower than 0.0057 under the testing high-frequency range of 1 GHz to 15 GHz. Overall, the BT resins modified by DBA display great potential to be applied in high frequency field.

scholarly journals Bi2O3-Modified Ceramics Based on BaTiO3 Powder Synthesized in Water Vapor

Inorganics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 8 ◽  
Author(s):  
Anastasia Kholodkova ◽  
Aleksey Smirnov ◽  
Marina Danchevskaya ◽  
Yurii Ivakin ◽  
Galina Muravieva ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Water Vapor ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Frequency Range ◽  
Batio3 Powder ◽  
Strength Determination ◽  
Water Vapor Atmosphere ◽  
Room Temperature Dielectric Constant

Bi2O3 was investigated in the role of a modifier for BaTiO3 powder synthesized in a water vapor atmosphere at 200 °C and 1.55 MPa. Modification was aimed at increasing the sinterability of the powder as well as improving the structural and dielectric properties of the obtained ceramics. The morphology and phase contents of the synthesized BaTiO3 powder were controlled by the methods of SEM and XRD. Properties of pure and Bi-doped BaTiO3 ceramics were comprehensively studied by XRD, SEM, dielectric spectroscopy, and standard approaches for density and mechanical strength determination. Doping with Bi2O3 favored BaTiO3 ceramic densification and strengthening. The room-temperature dielectric constant and the loss tangent of Bi-doped BaTiO3 were shown to stabilize within the frequency range of 20 Hz to 2 MHz compared to non-doped material. The drop of dielectric constant between room temperature and Curie point was significantly reduced after Bi2O3 addition to BaTiO3. Bi2O3 appeared to be an effective modifier for BaTiO3 ceramics produced from non-stoichiometric powder synthesized in water vapor.

Influence of CuO Additive on Density and Dielectric Properties of Ba(Zr0.05Ti0.95)O3 Ceramics Prepared by Molten Salt Method

2020 ◽  
Vol 302 ◽  
pp. 115-121
Author(s):  
Chompoonuch Warangkanagool
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Molten Salt ◽  
Room Temperature ◽  
Molten Salt Method ◽  
Distilled Water ◽  
Fluid Medium ◽  
Lcr Meter ◽  
Room Temperature Dielectric Constant

In this research, the Ba(Zr0.05Ti0.95)O3 powders were prepared by molten salt method. The powders were calcined at 600-1100°C for 3 h with heating rate of 5°C/min. The BZT powders were synthesized by molten salt method to reduce the calcination temperature by up to 300°C. The sintering procedure was carried out at 1250°C for 2 h with a heating/cooling rate of 5°C/min. Phase formation and microstructure were examined by XRD and SEM, respectively. The influence of the CuO additive on density and dielectric properties were investigated. The density of the sintered samples was measured by Archimedes method with distilled water as the fluid medium. Dielectric properties were examined by LCR meter. The BZT+2.0 mol% CuO ceramic sintered at 1250°C showed the highest density of 5.76 g/cm3, and the room temperature dielectric constant and dielectric loss at 1 kHz were 2687 and 0.01, respectively.

Dielectric and impedance spectroscopy of K+-doped MgAl2O4 nanoparticles

2018 ◽  
Vol 32 (15) ◽  
pp. 1850189
Author(s):  
Javed Ahmad ◽  
S. H. Bukhari ◽  
M. Qadeer Awan ◽  
M. Ehsan Mazhar ◽  
A. R. Makhdoom
Keyword(s):  
Dielectric Constant ◽  
Impedance Spectroscopy ◽  
High Frequency ◽  
Dielectric Response ◽  
Room Temperature ◽  
Parent Compound ◽  
Low Frequency ◽  
Space Charge Polarization ◽  
Relaxation Phenomena ◽  
Frequency Range

In this study, the dielectric response of Potassium (K[Formula: see text])-doped magnesium aluminates nanoparticles (Mg[Formula: see text]K[Formula: see text]Al2O4, x = 0.0, 0.25, 0.5, 0.75, 1.0) have been investigated as a function of frequency (20 Hz to 2 MHz) at room-temperature. Interestingly, the behavior of dielectric constant indicated the ionic or space charge polarization in the low-frequency range and it remains almost constant at high frequency. However, the value of conductivity increases at higher frequencies which is consistent with the previously reported results for the parent compound MgAl2O4. Moreover, the Cole–Cole plots represent various relaxation phenomena reflecting the existence of grain (boundaries) resistance effects.

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