Dielectric behavior of a quaternary composite (RE, BT, MnO2, CaO) in the band (DC–2 GHz)

2018 ◽  
Vol 84 (1) ◽  
pp. 10201 ◽  
Author(s):  
Mounir Bouchaour ◽  
Juan Pablo Martínez Jiménez ◽  
Nacerdine Bouzit ◽  
Nacerdine Bourouba
Keyword(s):  
Atmospheric Pressure ◽  
Room Temperature ◽  
Volume Fraction ◽  
Low Frequency ◽  
Wide Band ◽  
Dielectric Behavior ◽  
Resin Matrix ◽  
Ternary Composite ◽  
Dielectric Characterization

The main objective of this paper is to study the dielectric behavior of a quaternary composite, made from a mixture of barium titanate (BT), manganese dioxide (MnO2) and calcium oxide (CaO) in the same epoxy resin matrix (RE) maintained at 70% by volume fraction, while those of the other constituents are variable and completing each other in a way to achieve the remaining proportion, i.e. 30%. Random mixtures are made at room temperature and under atmospheric pressure. A dielectric characterization of this mixture type was performed by time-domain spectroscopy (TDS) over a frequency wide band (DC–2 GHz). This has been carried out to illustrate the effect of two oxides (MnO2 and CaO) simultaneously at low frequency (500 MHz), in the presence of (BT), on the composite dielectric behavior. This has led consequently to make a comparison between the present acquired results and those of the ternary composite, where (MnO2) and (CaO) act separately. The results obtained so far in this study allowed us to check the validity of the modified Lichtenecker law (MLL)-based predictive model in the quaternary composite case. The interest of this study lies on applications of these materials in microelectronics circuits and absorber materials in telecommunication domain.

scholarly journals Electrical and Dielectric Characterization of Bi12GeO20Prepared by Modified Pechini Method

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
C. G. P. Moraes ◽  
F. A. A. Jesus ◽  
Z. S. Macedo
Keyword(s):  
Volume Fraction ◽  
Pechini Method ◽  
Dark Conductivity ◽  
High Frequencies ◽  
Dielectric Characterization ◽  
Calcination Temperatures ◽  
Grain Sizes ◽  
Synthesis Parameters ◽  
Modified Pechini Method

Bismuth germanate (Bi12GeO20) ceramics were produced using modified Pechini route, and the synthesis parameters, crystalline phases, microstructure, and sintering conditions were investigated.Bi12GeO20powders with submicrometric particle sizes were investigated for calcination temperatures from 400 to 600°C, with soaking times of 1 h and 5 h. Controlling the synthesis parameters, dense ceramics with two different grain sizes of 3.4 ± 0.5 µm and 5.7 ± 0.8 µm could be produced after sintering at 750°C/1 h. The electric and dielectric properties of these ceramics were determined by impedance spectroscopy (IS). From the results, it was concluded that the dielectric permittivity measured at high frequencies is insensitive to the grain size, while the AC dark conductivity presents a noticeable dependency on this feature. This behaviour was discussed on the basis of a Maxwell-Wagner interfacial relaxation, whose intensity depends directly on the volume fraction of grain boundaries in the sample.

Characterization of a ruthenium/titania catalyst for selective methanation at room temperature and atmospheric pressure

Langmuir ◽  
1991 ◽  
Vol 7 (11) ◽  
pp. 2642-2648 ◽  
Author(s):  
K. Ravindranathan. Thampi ◽  
L. Lucarelli ◽  
John. Kiwi
Keyword(s):  
Atmospheric Pressure ◽  
Room Temperature

Characterization of SiC Implanted with B or Al Using Thermal Admittance Spectroscopy

2002 ◽  
Vol 719 ◽  
Author(s):  
S.R. Smith ◽  
M.A. Capano ◽  
A.O. Evwaraye
Keyword(s):  
Thermal Activation ◽  
Room Temperature ◽  
Schottky Diodes ◽  
Low Frequency ◽  
Energy Shift ◽  
Shallow Donor ◽  
Admittance Spectroscopy ◽  
Capacitance Voltage ◽  
Dopant Atoms

AbstractWe have measured the thermal activation energies of electrically active defects in 4H- and 6H-SiC implanted with either Al or B ions, using Thermal Admittance Spectroscopy. The net acceptor concentrations were monitored using room temperature low frequency Capacitance-Voltage measurements. The substrates were n/n+ epilayers. The implantations plus annealing produced p-type layers that were acceptable for characterization. The specimens were annealed in Ar at 1600 ° C, after which Ni Schottky diodes were fabricated on the specimens. Annealing times were 5, 15, 30, and 60 min. In some of the specimens, a shallow level was found that did not correspond to known levels. As the annealing progressed, energy shifts were noted for some of the detected levels. In some specimens, the implanted p-type impurity and the n-type residual dopants in the substrate were simultaneously detected. Measurements of electrically active ptype species were compared to “control” specimens implanted with Ar. From this comparison, we conclude that at least one shallow donor level is introduced into the bandgap by the implantation process, and is not annealed out. The defects associated with the implantation may affect actual device performance of diodes by destabilizing the lattice occupation of the implanted dopant atoms (energy shift with annealing), and act as lifetime killers.

The Effects of Particle Size, Morphology, and Mass Loading on the Reactivity of Nanocatalytic Particles

2007 ◽  
Author(s):  
Brian Fellon ◽  
Christopher Ricciuti ◽  
Yi Ma ◽  
Tiffany Miller ◽  
Howard Pearlman
Keyword(s):  
Particle Size ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Initial Temperature ◽  
Mass Loading ◽  
Oak Ridge ◽  
Portable Power ◽  
Effect Of Particle Size ◽  
Operating Temperatures

Nanocatalytic particles of Gold (Au), Platinum (Pt), and Palladium (Pd) are highly reactive at room-temperature and can be used to generate heat in micro-scale devices for portable power generation. No pre-heating is required for light-off and high steady-state operating temperatures can be sustained with high density alcohol-air premixtures. Preliminary experiments conducted in our lab and those reported by Hu and co-workers at Oak Ridge National Lab have measured peak operating temperatures ∼ 300–500 degrees Celsius using near-stoichiometric methanol/air and ethanol/air premixtures at ambient initial temperature and atmospheric pressure. The effect of particle size, morphology, mass loading, and flow residence time are reported for different mixture stoichiometries. Temperature measurements and gas species analyses are also tabulated. Interestingly, smaller particles were observed to be less reactive than larger particles for the same mass loadings for select conditions. Materials characterization of the particles has also been conducted to characterize the specific surface area of the catalyst and evaluate the importance of particle sintering, morphology changes, and particle distribution.

scholarly journals Electromagnetic Characterization of a Composite (RE-CB-MT) by Time Domain Spectroscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Amina Bounar ◽  
Nacerdine Bouzit ◽  
Nacerdine Bourouba
Keyword(s):  
Time Domain ◽  
Ternary Mixture ◽  
Strong Dependence ◽  
Low Frequency ◽  
Theoretical Models ◽  
Dielectric Behavior ◽  
Frequency Range ◽  
Time Domain Spectroscopy ◽  
Percolation Phenomenon

The aim of this article is to study the dielectric behavior (ε, σ) in microwaves domain of composites made with Epoxy Resin (RE), Carbon Black (CB), and Magnesium Titanate (MT) on a large band of frequency. This kind of composites is very solicited for applications and miniaturization of the components circuits (cavities, antennas, substrates, etc.) in hyperfrequency electronics. In this study we have also highlighted the effect of the fillers nature and their concentrations on the behavior of these composites. The results obtained by time domain spectroscopy (TDS) have revealed the strong dependence of complex permittivity of the composite materials on both the nature and the concentration of conductive environment. Low frequency analysis (500 MHz) has been investigated to determine the conductivity of composites which is related to the percolation phenomenon. Moreover, the comparison between experimental results and theoretical models shows that the modeling Lichtenecker law is applicable to the ternary mixture in this frequency range and is in accordance with the approach postulated by Bottreau.

scholarly journals Dielectric characterization of the system Sr1-xGdxTi1-xCoxO3 (x = 0.10) using impedance spectroscopy

2010 ◽  
Vol 7 (2) ◽  
pp. 499-504
Author(s):  
H. S. Tewari ◽  
P. K. Sakharkar
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Electrical Behavior ◽  
Cooling Rates ◽  
Impedance Analyzer ◽  
Dielectric Characterization

The structure of ceramic grain boundaries, boundary composition, the boundary charge and associated space charge controls the dielectric and electrical behavior of ceramics. Various methods were researched and applied to increase the dielectric constant by formation of insulating layers between semi-conducting grains. In this communication, we are reporting the effect of cooling rates from sintering temperature to room temperature on dielectric properties of the resulting ceramics in the system, Sr1-xGdxTi1-xCoxO3 with x = 0.10. All the samples in this system were prepared by conventional high temperature solid state reaction method. The samples were cooled at different cooling rates from sintering temperature to room temperature. The capacitance and dielectric loss were measured as a function of frequency and temperature using HP 4192A LF impedance analyzer. The samples cooled from different cooling rates from sintering temperature show interesting dielectric properties due to formation of insulating layers between grains. The impedance spectroscopy is used successfully in explaining the dielectric properties of these materials.

scholarly journals Characterization of SiNx film by room temperature low frequency (50Hz) plasma CVD.

Shinku ◽  
1987 ◽  
Vol 30 (9) ◽  
pp. 722-728
Author(s):  
Noriaki ODA ◽  
Mitsuo SHIMOZUMA ◽  
Hiroaki TAGASHIRA
Keyword(s):  
Room Temperature ◽  
Low Frequency ◽  
Plasma Cvd ◽  
Sinx Film
Sign in / Sign up

Export Citation Format

Share Document