scholarly journals Measurement of Dielectric and Magnetic Constants of Ferrofluid-Doped Sol-Gels by a Resonant Cavity Method

2021 ◽  
pp. 29-36
Author(s):  
B. Mahamout Mahamat ◽  
O. B. Arafat ◽  
B. Sauviac ◽  
M. F. Blanc-Mignon ◽  
S. Neveu ◽  
...  
Keyword(s):  
Volume Concentration ◽  
Sol Gel ◽  
Resonant Cavity ◽  
Dielectric Constants ◽  
Electromagnetic Properties ◽  
Cavity Method ◽  
Passive Components ◽  
Materials Properties ◽  
The Matrix

Materials with specific electromagnetic properties are increasingly used for the realization of passive components. Therefore, electromagnetic characterization is a priority to know these materials properties. This study focuses on the electromagnetic characterization of 10 nm maghemite ferrofluid doped sol-gel using a resonant cavity method. We deposited the sol-gel by dipping/removal on an alumina substrate in order to make measurements on the cavity to determine the complex permittivity and permeability. Two studies were carried out; the first consisted in varying the doped sol-gel thickness of layers of the same concentration in the realization of samples; and the second consisted in varying the volume concentration of ferrofluid according to the matrix dimensions. The first study showed that the dielectric constants do not vary with the thickness of the magnetic sol-gel layers. In the second study, measurements also showed that the gyromagnetic resonance is the same for all samples regardless of the ferrofluid volume concentration.

In—Line Measurement Of High Temperature Dielectric Constant In The Process Of Sintering

1996 ◽  
Vol 430 ◽  
Author(s):  
Zhou Jian ◽  
Cheng Jiping ◽  
Tang Yuling ◽  
Qiu Jinyu
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Resonant Cavity ◽  
Ceramic Materials ◽  
Dielectric Constants ◽  
Experimental Results ◽  
Cavity Method ◽  
Experimental Basis ◽  
Ceramic Samples ◽  
Line Measurement

AbstractIn this paper, a resonant cavity method is developed and some experimental results for measuring dielectric constants of ceramic samples (e. g. Al2O3) under different sintering temperatures are reported. The experiments show that this method has higher precision and good prospects of in—line monitoring the high temperature dielectric constant in the process of raising the temperature of the samples. These results provide some scientific experimental basis for physical research of ceramic materials.

Dielectric and Transverse Piezoelectric Characterization of Sol-Gel Derived Pb(Mg1/3Nb2/3)O3-PbTiO3 (70/30) FILMS WITH {100} and {111} Textures

1999 ◽  
Vol 596 ◽  
Author(s):  
Jeong Hwan Park ◽  
Susan Trolier-McKinstry
Keyword(s):  
Film Thickness ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Silicon Substrates ◽  
Sol Gel Process ◽  
Oriented Films ◽  
Tan Δ ◽  
Passivated Silicon ◽  
Pt Films

AbstractHighly {100} and {111} oriented Pb(Mg1/3Nb2/3)O3-PbTiO3 (70/30) films were deposited on Pt(111)-passivated silicon substrates using a modified sol-gel process. In both cases, the degree of preferred orientation did not change with film thickness from 0.56 μm to 1.5 μm. The room temperature dielectric constants for the {100}-oriented films were 2100–2650, while those for the {111} oriented films were 1900–2350. In both cases tan δ was less than 0.03. It was found that the piezoelectric coefficient (d31) of the PMN-PT films increased with increasing film thickness. The d31 coefficient of highly {100} oriented PMN-PT films poled for 5 minutes at 85 kV/cm were found to range from –45 to –86 pC/N assuming a Young's modulus of 35 GPa. Highly {100} oriented PMN-PT films showed larger piezoelectric coefficients than {111} oriented films. Results on aging of the piezoelectric coefficients for the differently oriented films are also presented.

Manufacturing radar-absorbing composite materials by using magnetic Co-doped zinc oxide particles synthesized by Sol-Gel

2020 ◽  
Vol 54 (26) ◽  
pp. 4059-4066
Author(s):  
Hüsnügül Yilmaz Atay ◽  
Öykü İçin
Keyword(s):  
Zinc Oxide ◽  
Sol Gel ◽  
Electromagnetic Properties ◽  
X Ray Diffraction ◽  
Important Place ◽  
Stealth Technology ◽  
Absorbing Materials ◽  
Potential Applications ◽  
Co Doped

An indicator of being a strong country in today's world is that they have powerful weapons. In this sector where science is used exceedingly, the “stealth” takes an important place. Radar-absorbing materials are used in stealth technology to disguise an object from radar detection, such that it can allow a plane to be perceived as a bird. In this study, Co-doped zinc oxide reinforced styrofoam sheet composites were manufactured as radar-absorbing materials. For this purpose, Co-doped zinc–ZnO particles were synthesized via the Sol-Gel method with doping concentrations of 0%, 3%, 6%, 9%, and 12%. They were embedded in a styrofoam matrix with different loading levels to see the concentration dependence. The as-prepared powders were characterized by using X-ray diffraction and Scanning Electron Microscope-Energy Dispersive Spectroscopy. Magnetic characterization of samples was carried out using a vibrating sample magnetometer. Finally, the radar-absorbing test was applied with a network analyzer to achieve the main purpose of this research. It was concluded that Co-doped zinc oxide reinforced composites have electromagnetic properties that indicate potential applications in the radar-absorbing area.

scholarly journals Optical Characterization of Chemically Etched Nanoporous Silicon Embedded in Sol-Gel Matrix

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
A. S. Al Dwayyan ◽  
M. Naziruddin Khan ◽  
M. S. Al Salhi
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Spherical Shape ◽  
Nanoporous Silicon ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Si Nanoparticles ◽  
The Matrix ◽  
Crystalline Nature

Nanoporous (NPs) silicon fabricated by chemical etching process in HF acid was first separated in tetrahydrofuran (THF) solvent and then incorporated into SiO2matrix. The matrix was prepared by sol gel process in which dimethylformamide (DMF) was used as drying chemical control additive (DCCA) to form crack-free dried sample. We examined the optical properties of NPs in three medium which are solvent, sol, and dried sol gel. Our observations reveal that absorption spectra of NPs silicon in THF are modified with respect to the spectra in sol gel. Significant stability in PL of NPs silicon in the sol gel is observed. Influence of matrix environment on peaks of NPs is also discussed. Surface morphology is characterized by field emission scanning electron microscopy (FESEM) which shows that the NPs silicon in THF is similar to the sol gel but becomes aggregation particle to particle. Presence of Si nanoparticles in THF and sol is confirmed by Transmission electron microscopy (TEM). The NPs silicons have mono dispersive and high crystalline nature with spherical shape of around 5 nm in sizes.

scholarly journals Design of Substrate-Integrated Waveguide Loading Multiple Complementary Open Resonant Rings (CSRRs) for Dielectric Constant Measurement

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 857 ◽  
Author(s):  
Honggang Hao ◽  
Dexu Wang ◽  
Zhu Wang
Keyword(s):  
Dielectric Constant ◽  
Quality Factor ◽  
Ground Plane ◽  
Resonant Cavity ◽  
Frequency Offset ◽  
Dielectric Constants ◽  
Complex Dielectric Constant ◽  
Cavity Method ◽  
Substrate Integrated Waveguide ◽  
Wide Range

In order to solve the low-sensitivity problem of the dielectric constant with the resonant cavity method, a sensor based on a substrate-integrated waveguide structure loaded with a multi-complementary open resonant ring is proposed. With the enhanced resonance characteristics of the sensor, this design realized the measurement of complex dielectric constants in a wide range. The frequency selectivity of the sensor is improved by the high-quality factor of the substrate-integrated waveguide. By loading three complementary resonant rings with different opening directions in the ground plane, a deeper notch and better out-of-band suppression are achieved. The effect of the complex dielectric constant on both resonant frequency and quality factor is discussed by calculating the material under test with a known dielectric constant. Simulation and experimental results show that a resonance frequency offset of 102 MHz for the per unit dielectric constant is achieved. A wide frequency offset is the prerequisite for accurate measurement. The measurement results of four plates match well with the standard values, with a relative error of the real part of the dielectric constant of less than 2% and an error of less than 0.0099 for the imaginary part.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

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