DIELECTRIC PROPERTIES OF Ca2CuO3–CaCu2O3–CuO COMPOSITE CERAMICS

2013 ◽  
Vol 27 (06) ◽  
pp. 1350042 ◽  
Author(s):  
QING-SHOU LI ◽  
YUN-QIANG ZHANG ◽  
LI-BEN LI ◽  
GUO-ZHONG ZANG
Keyword(s):  
Dielectric Properties ◽  
Schottky Barrier ◽  
Dielectric Response ◽  
Oxygen Vacancies ◽  
Arrhenius Equation ◽  
Composite Ceramics ◽  
High Dielectric ◽  
Sintering Method ◽  
Very High ◽  
Barrier Model

The Ca 2 CuO 3– CaCu 2 O 3– CuO ceramics were synthesized by traditional solid-state sintering method. The complex dielectric response of the samples measured from 102–106 Hz and from 300–500 K reveals very high real part of ε > 104. The activation energy (being about 0.63 eV) calculated by the Arrhenius equation indicates that the oxygen vacancies may contribute to the high dielectric response. And the fitting to a Schottky barrier model of capacitance versus applied voltage suggests that the existence of Schottky barrier at the grain boundaries may be another important reason for the origination of good dielectric properties.

scholarly journals The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3230
Author(s):  
Theeranuch Nachaithong ◽  
Narong Chanlek ◽  
Pairot Moontragoon ◽  
Prasit Thongbai
Keyword(s):  
Dielectric Properties ◽  
Loss Tangent ◽  
Barrier Layer ◽  
Dielectric Response ◽  
High Resistivity ◽  
Low Loss ◽  
Rutile Tio2 ◽  
Complex Defect ◽  
Very High ◽  
Co Doped

(Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε′ » 36,105 and a low loss tangent of tanδ » 0.04 were achieved. The sample–electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped 2Nb2Ti complex defect. These two types of complex defects are far away from each other. Therefore, the electron-pinned defect dipoles cannot be considered the primary origins of the dielectric response in the CoNTO ceramics. Impedance spectroscopy shows that the CoNTO ceramics are electrically heterogeneous, comprised of insulating and semiconducting regions. Thus, the dielectric properties of the CoNTO ceramics are attributed to the interfacial polarization at the internal insulating layers with very high resistivity, giving rise to a low loss tangent.

Processing and the Microstructure of SrTiO3-Based Bl Capacitors using Pb(Fe, W)O3 Ferroelectrics

1989 ◽  
Vol 155 ◽  
Author(s):  
Makoto Kuwabara
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Grain Boundaries ◽  
Strontium Titanate ◽  
Barrier Layer ◽  
High Dielectric Constant ◽  
Ferroelectric Materials ◽  
New Type ◽  
High Dielectric ◽  
Very High

ABSTRACTA preliminary experiment was conducted to prepare semiconducting strontium titanate-based internal barrier layer capacitors with ferroelectric Pb(Fe, W)O3 forming insulating layers along the grain boundaries. Processing, microstructure and the dielectric properties of this new type of BL capacitors are described. The idea to obtain this type of BL capacitors with a very high dielectric constant may be realized when the ferroelectric materials can uniformly be diffused along the grain boundaries by using a more sophisticated processing of the second firing.

High dielectric response of 2D-polyaniline nanoflake based epoxy nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48421-48425 ◽  
Author(s):  
Meher Wan ◽  
Anoop K. Srivastava ◽  
Punit K. Dhawan ◽  
Raja Ram Yadav ◽  
Sudhindra B. Sant ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Epoxy Matrix ◽  
Dielectric Response ◽  
Two Dimensional ◽  
Epoxy Nanocomposites ◽  
High Dielectric

Nanocomposites of two dimensional nanoflake-like polyaniline fillers reinforced in an epoxy matrix have been synthesised and their dielectric properties have been investigated.

scholarly journals Enhanced dielectric properties with a significantly reduced loss tangent in (Mg2+, Al3+) co-doped CaCu3Ti4O12 ceramics: DFT and experimental investigations

RSC Advances ◽  
2021 ◽  
Vol 11 (40) ◽  
pp. 25038-25046
Author(s):  
Jakkree Boonlakhorn ◽  
Jedsada Manyam ◽  
Sriprajak Krongsuk ◽  
Prasit Thongbai ◽  
Pornjuk Srepusharawoot
Keyword(s):  
Dielectric Properties ◽  
Liquid Phase ◽  
Loss Tangent ◽  
Liquid Phase Sintering ◽  
Experimental Investigations ◽  
Low Loss ◽  
High Dielectric Permittivity ◽  
High Dielectric ◽  
Very High ◽  
Co Doped

Mg and Al atoms preferentially occupy Cu sites, creating liquid-phase sintering decomposition at grain boundary layers. This results in very high dielectric permittivity and a low loss tangent of the CaCu2.95Mg0.05Ti3.95Al0.05O12 ceramic.

Effects of Potassium Fluoride Salt Additive on the Sintering Temperature and Dielectric Properties of BaFe0.5Nb0.5O3 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 885-888 ◽  
Author(s):  
Uraiwan Intatha ◽  
K. Sathitada ◽  
Sukum Eitssayeam ◽  
Kamonpan Pengpat ◽  
Gobwute Rujijanagul ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Wide Temperature Range ◽  
Sintering Temperature ◽  
Potassium Fluoride ◽  
Fluoride Salt ◽  
Temperature Range ◽  
High Dielectric ◽  
Very High ◽  
Diffuse Phase

BaFe0.5Nb0.5O3 (BFN) exhibits very high dielectric constant over a wide temperature range. However, these materials normally require high-temperature sintering to achieve a maximum densification. The aim of this study is to determine the effect of potassium fluoride salt on the sintering and dielectric properties of BFN ceramics. The results show that KF additive lower the sintering temperature by 100-200°C without affecting the formation of BFN phase. Ceramics doped with 1% KF show optimum densities of about 95% of the theoretical value when sintered at 1300°C. The addition of fluoride salt in the BFN ceramics causes very broad dielectric constant curves over a wide temperature range indicating the diffuse phase transition characteristic. Furthermore, this addition also reduces in the dielectric loss when compared with pure BFN ceramics

Dielectric Properties of TiO2-NiO Ceramics and Its Response Mechanism

2007 ◽  
Vol 280-283 ◽  
pp. 115-118
Author(s):  
Jian Fei Wang ◽  
Yuan Hua Lin ◽  
Yu Chen ◽  
Lei Jiang ◽  
Ce Wen Nan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Response Mechanism ◽  
Composite Ceramics ◽  
Conventional Solid State Reaction ◽  
High Dielectric

NiO-NiTiO3 composite ceramics were prepared by the conventional solid state reaction process and dielectric properties were investigated as a function of frequency and temperature. The results indicate that all samples showed high dielectric constant ~103 at 0.1 kHz, but a remarkable decrease of the dielectric loss appeared when the volume fraction of NiTiO3 phase reached 42.4%. Relaxor-like peaks were observed in the temperature dependence of the dielectric constant with ceramics having low composition of NiTiO3 phase (≤21.2%). The possible response mechanism associated with the microstructure and the associated defects of the composites was discussed.

Preparation and Properties of Si3N4-BaTiO3 Composite Ceramics

2018 ◽  
Vol 281 ◽  
pp. 646-651
Author(s):  
Ping Ping Zhang ◽  
Jing Man ◽  
Hong Sheng Wang ◽  
Qi Hong Wei ◽  
Ying Gai ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Materials ◽  
Composite Ceramics ◽  
Pure Matrix ◽  
Constant E ◽  
Power Content ◽  
Mechanical Performances ◽  
High Dielectric Materials ◽  
High Dielectric ◽  
Gas Pressure Sintering

Si3N4-BaTiO3 composite ceramics, a type of high dielectric materials applied in the multifunction radome, were prepared by gas pressure-sintering method. The influences of BaTiO3 power content on the mechanical performances, dielectric properties and microstructure of Si3N4-BaTiO3 composite ceramics were investigated. The results showed that the sintering density, the elastic modulus and the flexural strength of Si3N4-BaTiO3 composite ceramics all firstly increased and then decreased along with the increase of BaTiO3 power in sample. Meanwhile, Relationship between BaTiO3 power content and dielectric properties of Si3N4-BaTiO3 composite ceramics within the frequency range of 8.2–12.4 GHz (X-band) was studied. The average of dielectric constant e of Si3N4-BaTiO3 composite ceramics increased from 7.33 to 9.98 and the average of dielectric loss tand increased from 2.8 ´ 10-3 to 0.0168 when the content of BaTiO3 power increased from 0 to 25 wt.%. The increase of the dielectric properties of Si3N4–BaTiO3 composite ceramics were attributed to the electronic and molecular polarization at interface between Si3N4 and BaTiO3, compared with the pure matrix Si3N4.

Dielectric Response of Ceramic-Polymer Composite with High Permittivity

2008 ◽  
Vol 1134 ◽  
Author(s):  
Xiaobing Shan ◽  
Lin Zhang ◽  
Pei-xuan Wu ◽  
Canran Xu ◽  
Zhong-Yang Cheng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Response ◽  
Casting Method ◽  
Uniform Size ◽  
Layer Composite ◽  
Solution Casting Method ◽  
High Dielectric ◽  
High Flexibility ◽  
Sintering Method ◽  
Nano Size

AbstractBased on solution casting method, a ceramic [CaCu3Ti4O12 (CCTO)]-Polymer [P(VDF-TrFE)] composite with flexibility has been synthesized and its dielectric response has been studied. The CCTO ceramic powders were prepared by traditional sintering method and were milled with a relative uniform size. The dielectric properties of these films with micro-size and nano-size CCTO particle, as well as different polymer matrixes were determined. The process was optimized by hot pressing and surface modification to achieve high dielectric constant. A dielectric constant about 175 for one layer composite with high flexibility using silane coupling agent was obtained at 1 kHz at room temperature.

scholarly journals Experimental Characterization of Dielectric Properties in Fluid Saturated Artificial Shales

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Roman Beloborodov ◽  
Marina Pervukhina ◽  
Tongcheng Han ◽  
Matthew Josh
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Data Interpretation ◽  
Dielectric Anisotropy ◽  
Geomechanical Properties ◽  
High Dielectric ◽  
Rock Microstructure

High dielectric contrast between water and hydrocarbons provides a useful method for distinguishing between producible layers of reservoir rocks and surrounding media. Dielectric response at high frequencies is related to the moisture content of rocks. Correlations between the dielectric permittivity and specific surface area can be used for the estimation of elastic and geomechanical properties of rocks. Knowledge of dielectric loss-factor and relaxation frequency in shales is critical for the design of techniques for effective hydrocarbon extraction and production from unconventional reservoirs. Although applicability of dielectric measurements is intriguing, the data interpretation is very challenging due to many factors influencing the dielectric response. For instance, dielectric permittivity is determined by mineralogical composition of solid fraction, volumetric content and composition of saturating fluid, rock microstructure and geometrical features of its solid components and pore space, temperature, and pressure. In this experimental study, we investigate the frequency dependent dielectric properties of artificial shale rocks prepared from silt-clay mixtures via mechanical compaction. Samples are prepared with various clay contents and pore fluids of different salinity and cation compositions. Measurements of dielectric properties are conducted in two orientations to investigate the dielectric anisotropy as the samples acquire strongly oriented microstructures during the compaction process.

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