scholarly journals STRUCTURAL AND DIELECTRIC PROPERTIES OF GLASSES IN THE SYSTEM TeO2–CaCu3Ti4O12

2012 ◽  
Vol 02 (04) ◽  
pp. 1250020 ◽  
Author(s):  
P. THOMAS ◽  
K. B. R. VARMA
Keyword(s):  
Dielectric Constant ◽  
Electric Modulus ◽  
Differential Scanning Calorimetric ◽  
Frequency Range ◽  
Low Loss ◽  
Modulus Formalism ◽  
X Ray ◽  
Dielectric Constant And Loss ◽  
Frequency Independent ◽  
Electric Modulus Formalism

The glasses in the system (100 - x) TeO2 –x CaCu3Ti4O12 , (x = 0.25 mol. % to 3 mol.%) were fabricated. The color varied from olive green to brown as the CaCu3Ti4O12 (CCTO) content increased in TeO2 matrix. The X-ray powder diffraction and differential scanning calorimetric analyses that were carried out on the as-quenched samples confirmed their amorphous and glassy nature respectively. The dielectric constant and loss in the 100 Hz–1 MHz frequency range were monitored as a function of temperature (50–400°C). The dielectric constant [Formula: see text] and the loss (D) increased as the CCTO content increased in TeO2 at all the frequencies and temperatures under investigation. Further, the [Formula: see text] and D were found to be frequency-independent in the 50–200°C temperature range. The value obtained for the loss at 1 MHz was 0.0019 which was typical of low loss materials, and exhibited near constant loss (NCL) in the 100 Hz–1 MHz frequency range. The electrical relaxation was rationalized using the electric modulus formalism. These glasses may be of considerable interest as substrates for high frequency circuit elements in conventional semiconductor industries owing to their high thermal stability.

Heteroepitaxial Growth of Ba0.5Sr0.5TiO3/SrRuO3 on YSZ/Si by Off-Axis Sputtering

1994 ◽  
Vol 361 ◽  
Author(s):  
S.Y. Hou ◽  
J. Kwo ◽  
R.K. Watts ◽  
J.-Y. Cheng ◽  
R.J. Cava ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Degree Of Crystallinity ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Dielectric Constant And Loss ◽  
Bst Films ◽  
High Degree ◽  
Room Temperature Dielectric Constant

ABSTRACTWe demonstrate an epitaxial heterostructure of Ba0.5Sr0.5 TiO3/SrRuO3/YSZ on Si for potential charge storage applications. The dielectric Ba0.5Sr0.5TiO3 (BST) and conductive oxide SrRuO3 are both grown (110) oriented on YSZ (100) buffered Si by 90° off-axis sputtering. These films showed a high degree of crystallinity with minimal interdiffusion at the interfaces as examined by X-ray diffraction, Rutherford backscattering spectroscopy, and cross-section transmission electron microscopy. The in-plane epitaxial alignment of the films is BST/SRO 〈111〉 // YSZ 〈110〉 with a four-fold degeneracy. The dielectric constant and loss tangent of the epi-BST films are 360 and 0.01 at 10 kHz. The leakage current density is < 4×10∼−7 A/cm2 at 1 V. The room temperature dielectric constant (ε) of the BST films shows a roll-off in the 1–10 MHz range. This is attributed to the existence of a series resistance in the measurement circuit, which likely arises from the SrRuO3 electrode.

Preparation and Characterization of Ce-Doped Ba0.2Sr0.8TiO3 Ferroelectric Ceramics

2010 ◽  
Vol 97-101 ◽  
pp. 1091-1096
Author(s):  
Dong Fang Han ◽  
Qun Tang ◽  
Qing Meng Zhang ◽  
Lei Wang ◽  
Ju Du
Keyword(s):  
Dielectric Constant ◽  
Xrd Analysis ◽  
Ferroelectric Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Property ◽  
Dielectric Constant And Loss ◽  
Ce Content ◽  
Doping Ratio

The structure and property of Ce-doped Ba0.2Sr0.8TiO3 (BST) were investigated as a function of Ce content. The density experiment results confirmed that increasing the Ce doping ratio caused the decrease in shrinkage factor of BST in the sintering procedure. Additionally, both Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) analysis showed that the grain size of Ce-doped BST was dependent on the Ce content. Further more, the dielectric constant and dielectric loss had a curve relationship with increasing Ce content. The improvement of the electrical properties of Ce doping BST may be related to the decrease in the concentration of oxygen vacancies. According to the research, the diameter of grain, the dielectric constant and loss factor of the 1mol% Ce-doped Ba0.2Sr0.8TiO3 were 500nm, 365.8 and 0.0063, respectively.

Prediction of Electrical Properties of Plain-Weave Fabric Composites for Printed Wiring Board Design

1993 ◽  
Vol 115 (2) ◽  
pp. 219-224 ◽  
Author(s):  
R. K. Agarwal ◽  
A. Dasgupta
Keyword(s):  
Dielectric Constant ◽  
Loss Tangent ◽  
Effective Properties ◽  
Mechanistic Model ◽  
Three Dimensional ◽  
Unit Cell ◽  
Woven Fabric ◽  
Effective Dielectric Constant ◽  
Low Loss ◽  
Dielectric Constant And Loss

A mechanistic model is presented for predicting the effective dielectric constant and loss tangent of woven-fabric reinforced composites with low-loss constituents. A two-scale asymptotic homogenization scheme is used to predict the orthotropic effective properties. A three-dimensional unit-cell enclosing the characteristic periodic repeat pattern in the fabric weave is isolated and modeled mathematically. Electrostatic boundary value problems (BVP’s) are formulated in the unit-cell and are solved analytically to predict effective dielectric constant of the composite, using three-dimensional series-parallel reactance nets. Results are also verified numerically, using finite element methods. The effective dielectric constant and the effective loss tangent are then obtained, analogous to mechanical viscoelastic problems for low-loss materials. The predicted dielectric constant and loss tangent are compared with experimental results for E-glass/epoxy laminates. Frequency dependence of the effective dielectric constant and loss tangent is obtained from the corresponding behavior of the constituent materials. Trade-off studies are conducted to investigate the effect of the constituent material properties on orthotropic effective dielectric permittivity.

Electrical Relaxation Studies in Fluorite Oxides

1988 ◽  
Vol 135 ◽  
Author(s):  
Partho Sarkar ◽  
Patrick S. Nicholson
Keyword(s):  
Solid Solutions ◽  
Oxygen Vacancies ◽  
Electric Modulus ◽  
Dopant Concentration ◽  
Low Frequency ◽  
Relaxation Processes ◽  
Modulus Formalism ◽  
Free Oxygen ◽  
Range Migration ◽  
Electric Modulus Formalism

AbstractElectric relaxation in CeO2-M203 (M34 sY3+, La3+) solid solutions has been investigated as a function of temperature (373K-673K) using the electric modulus formalism in the frequency range 5 to 107Hz. Two relaxation processes are observed in dilute solid solutions. The low frequency process is identified as a long range migration of free oxygen-vacancies (Process A) and the high frequency process is due to reorientation relaxation of the (MceVo) charged associates (Process B). The relaxation process is analysed using a non-exponential decay function, ø(t)=exp[-(t/τo)B] for O<β≤1, of the electric field. The observed activation enthalpy minimum as a function of dopant concentration for the Process A is explained using the concept of incomplete dissociation of oxygen-vacancies from (MceVo) defect associates and the formation of higher-order defect clusters at higher mole% M203.

Achieving Ceramic-like RF Capacitor Requirements with Organic-based Materials

2010 ◽  
Vol 2010 (1) ◽  
pp. 000072-000075 ◽  
Author(s):  
Jin-Hyun Hwang ◽  
John Andresakis ◽  
Bob Carter ◽  
Yuji Kageyama ◽  
Fujio Kuwako
Keyword(s):  
Dielectric Constant ◽  
Form Factor ◽  
High Dielectric Constant ◽  
High Volume ◽  
Electrical Performance ◽  
Frequency Range ◽  
Large Area ◽  
Low Loss ◽  
Capacitance Variation ◽  
High Dielectric

New and novel organic-based composite materials for the use of embedded RF capacitors have been developed to address the important material issues by means of functional filler and resin chemistry. Combining different fillers with appropriate chemistries, the net composite can be made thermally stable while retaining the high dielectric constant and low loss. These composites attained dielectric constant of above 7 without compromising the quality factor in GHz frequency range. In addition, measurement of capacitance variation as a function of temperature (TCC) showed flatter TCC profile, resulting in TCC of ±30 ppm/°C over the temperature range −55°C to 125°C. It can be incorporated into organic chip package and, unlike ceramic-based LTCC they can utilize large area processing that is typical, and available in high volume manufacturing. This material is formulated for RF module designers to successfully implement embedded RF capacitors into their organic chip package designs and thus improve form factor, electrical performance and possibly reduce overall costs.

Low Loss LTCC Ag System for 5G Applications

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000105-000111
Author(s):  
Ellen Tormey ◽  
Chao Ma ◽  
John Maloney ◽  
Bradford Smith ◽  
Sid Sridharan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Frequency ◽  
Lower Cost ◽  
Low Dielectric Constant ◽  
Low Latency ◽  
Frequency Range ◽  
Low Loss ◽  
Green Tape ◽  
Low Dielectric ◽  
Wireless Telecommunications

Abstract Low dielectric constant/low loss LTCC materials have drawn much attention with the emergence of 5G wireless telecommunications. LTCC offers unique properties in the millimeter wave frequency range. The low dielectric constant and dielectric loss enable low latency devices with enhanced performance. To meet the market demands of higher performance and lower cost, Ferro has developed a new M7 LTCC/Ag cofireable system suitable for antenna in 5G and other high frequency applications. M7 LTCC ceramic green tape and cofireable Ag conductors have been developed and tested. Properties of the LTCC/Ag system are included herein including high frequency dielectric properties.

TRANSPORT PROPERTIES OF THERMALLY EVAPORATED In2Se3 THIN FILMS

2009 ◽  
Vol 16 (05) ◽  
pp. 723-729 ◽  
Author(s):  
D. NITHYAPRAKASH ◽  
B. PUNITHAVENI ◽  
J. CHANDRASEKARAN
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Ac Conductivity ◽  
Thermal Evaporation ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Cbh Model ◽  
X Ray ◽  
Correlated Barrier Hopping ◽  
Tan Δ

Thin films of In2Se3 were prepared by thermal evaporation. X-ray diffraction indicated that the as-grown films were amorphous in nature and became polycrystalline γ-In2Se3 films after annealing. The ac conductivity and dielectric properties of In2Se3 films have been investigated in the frequency range 100 Hz–100 kHz. The ac conductivity σ ac is found to be proportional to ωn where n < 1. The temperature dependence of both ac conductivity and the parameter n is reasonably well interpreted by the correlated barrier hopping (CBH) model. The values of dielectric constant ε and loss tangent tan δ were found to increase with frequency and temperature. The ac conductivity of the films was found to be hopping mechanism. In I–V characteristic for different field and temperature were studied and it has been found that the conduction process is Poole–Frenkel type.

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