scholarly journals Study of Dielectric Properties and Ultrasonic Attenuation in KDP-Type Ferroelectrics

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Vijay Singh Bist ◽  
Narayan Singh Panwar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dynamical Equation ◽  
Ultrasonic Attenuation ◽  
Tangent Loss ◽  
Stochastic Motion ◽  
Mode Behavior ◽  
Dielectric Constant And Loss ◽  
Model Hamiltonian ◽  
Physical Quantities

The soft mode dynamical model has been used to study dielectric properties and ultrasonic attenuation in KDP-type ferroelectric crystals. The model Hamiltonian proposed by Blinc and Zeks has been modified by considering lattice anharmonicity up to fourth-order. The correlations appearing in the dynamical equation have been evaluated using double-time thermal retarded Green’s functions method and Dyson’s equation. Without any decoupling, the higher order correlations, appearing in the dynamical equation, have been evaluated using the renormalized Hamiltonian. The expressions for collective frequencies, width, dielectric constant, ultrasonic attenuation, and tangent loss have been calculated. The dielectric properties and ultrasonic attenuation strongly depend on the relaxational mode behavior of stochastic motion of H2PO4 group in KDP-type ferroelectrics. By fitting model values of physical quantities, the temperature dependence of Sqz and Sqx for different value of four-body coupling coefficient and dielectric constant and loss tangent has been calculated. The calculated and observed results have been found in good agreement.

Broadband Dielectric Characterization of Aluminum Oxide (Al2O3)

2008 ◽  
Vol 5 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Khalid Z. Rajab ◽  
Mira Naftaly ◽  
Edmund H. Linfield ◽  
Juan C. Nino ◽  
Daniel Arenas ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Aluminum Oxide ◽  
Time Domain ◽  
Measurement Techniques ◽  
Thz Spectroscopy ◽  
Dielectric Characterization ◽  
Dielectric Constant And Loss ◽  
Ir Frequencies ◽  
Cofired Ceramics

Applications for low-temperature cofired ceramics (LTCC) and high-temperature cofired ceramics (HTCC) are advancing to higher frequencies. In order to design ceramic microsystems and electronic packages, the electrical properties of materials must be well characterized over a broad frequency range. In this study, the dielectric properties of commercial aluminum oxide (Al2O3) with different glass loadings are characterized using three different measurement techniques: the split-post cavity, terahertz (THz) time-domain spectroscopy, and Fourier transform IR spectroscopy (FTIR). Specifically, the dielectric properties will be characterized from 10 GHz to IR frequencies. A split-post cavity was employed for determination of dielectric properties in the 10 GHz range. A broadband THz spectroscopy technique was used to characterize the specimens using measured time-domain transmission data. The dielectric constant and loss were extracted from the sample's frequency-domain transmission characteristics, providing data between 100 GHz and 2 THz. Additionally, FTIR was used to characterize the samples from ~33 to 3300 cm−1 (~1–100 THz). The measurements from the three techniques are compared, and dielectric constant and loss data will be presented for commercial and experimental ceramic systems from 10 GHz to IR frequencies.

scholarly journals Dielectric Properties of Substrates for InkJet Technology in GHz Area

2019 ◽  
Vol 63 (1) ◽  
pp. 9-15
Author(s):  
Tibor Rovensky ◽  
Peter Lukacs ◽  
Alena Pietrikova
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Inkjet Printing ◽  
Measuring Method ◽  
Flexible Substrates ◽  
Network Analyzer ◽  
Dielectric Constant And Loss ◽  
Inkjet Printing Technology ◽  
Specific Material ◽  
Frequency Area

This paper is focused on investigation of dielectric properties of various substrates for InkJet printing technology. In addition this paper included investigation of dielectric properties' homogeneity. Dielectric constant and loss tangent of polymeric flexible substrates (Polyimide DuPont Kapton HN, PET Mylar A, PEN Teonex Q51) and insulation paper (Nomex 410) were measured in GHz frequency area. Measurements were done by combination of vector network analyzer and split cylinder resonator. This measuring method provides dielectric properties at frequency around 10 GHz, the exact value of frequency may vary depends on specific material and its resonant frequency. Experiments included two types of samples, 6 x 6 cm which is recommended area for measurements of dielectric properties by split cylinder resonator and 12 x 12 cm for measurements of dielectric properties' homogeneity (one sheet contains 9 overlapping measuring areas 6 x 6 cm). All measured values of dielectric constant and dielectric losses were statistically processed and depicted by SigmaPlot software. The paper shows values of dielectric properties at GHz frequency area as they are lacking in datasheets from manufacturers and evaluate homogeneity of measured substrates.

Synthesis and Characteristics of MgO Coated BST-Mg2TiO4 Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1180-1183
Author(s):  
Qian Qian Jia ◽  
Hui Ming Ji ◽  
Shan Liu ◽  
Xiao Lei Li ◽  
Zheng Guo Jin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Curie Temperature ◽  
Loss Tangent ◽  
Phase Shifters ◽  
Precipitation Method ◽  
Composite Ceramics ◽  
Low Dielectric ◽  
Dielectric Constant And Loss ◽  
Bst Ceramics

The (Ba, Sr)TiO3 (hereafter BST) ceramics are promising candidate for applying in tunable devices. MgO coated BST-Mg2TiO4 (BSTM-MT) composite ceramics were prepared to obtain the low dielectric constant, low dielectric loss, good dielectric constant temperature stability, and high tunability of BST ceramics. The Ba0.55Sr0.40Ca0.05TiO3 nanoparticles were coated with MgO using the precipitation method and then mixed with Mg2TiO4 powders to fabricate BSTM-MT composite ceramics. The morphologies, phases, elements, and dielectric properties of the sintered ceramics were investigated. The core-shell structure of BST powder wrapped with MgO was clearly observed from the TEM image. After sintered at 1100 °C for 2 h, the composite ceramics expressed dense microstructures from SEM images and two main phases BST and Mg2TiO4 were detected in the XRD patterns. The dielectric constant and loss tangent were both reduced after the coating. The reduced dielectric constant and loss tangent of BSTM-MT were 190, 0.0011 (2MHz), respectively. The ceramics exhibited the diffuse phase transition near the Curie temperature and the Curie temperature shifted from 10 °C to 5 °C after the coating. Since the continuous Ti-O bonds were disconnected with the MgO coating, the tunability was reduced to 15.14 % under a DC bias field of 1.1 kV/mm. The optimistic dielectric properties made it useful for the application of tunable capacitors and phase shifters.

Investigations on the Structural, Optical and Dielectric Properties of Ball-Milled ZnO–Fe2O3 Nanocomposites

2020 ◽  
Vol 19 (04) ◽  
pp. 1950034
Author(s):  
V. Balachandar ◽  
J. Brijitta ◽  
K. Viswanathan ◽  
R. Sampathkumar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Ball Milling ◽  
High Energy ◽  
X Ray Diffraction ◽  
Dielectric Constant And Loss ◽  
Energy Ball ◽  
Uv Visible ◽  
Ball Milling Technique ◽  
Xrd Patterns

In this study, ZnO–Fe2O3 nanocomposites were prepared by high-energy ball milling technique and characterized through X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), UV–visible spectroscopy and dielectric spectroscopy. The amount of Fe2O3 in the ZnO–Fe2O3 nanocomposites was varied at the rates of 1[Formula: see text]wt.%, 3[Formula: see text]wt.% and 5[Formula: see text]wt.% in order to investigate its influence on the structural, optical and dielectric properties of the nanocomposites. XRD patterns of nanocomposites revealed no shift in peak positions and hence confirmed the formation of composites after ball milling. Further, it was observed from FESEM analysis that Fe2O3 particles were distributed randomly on the ZnO matrix of the nanocomposites. ZnO–Fe2O3 nanocomposites reveal extended optical absorption in the range of 400–600[Formula: see text]nm from UV studies. The dielectric constant and loss of the nanocomposites decrease exponentially with increase in frequency. The composition and frequency dependences of the dielectric constant, dielectric loss and AC conductivity are explained based on the Maxwell–Wagner effect and Koop’s theory.

scholarly journals Dielectric Properties of Deuterated Cesium Dihydrogen Phosphate Crystal

2021 ◽  
Vol 16 (2) ◽  
Author(s):  
Muzaffar Iqbal Khan ◽  
Trilok Chandra Upadhyay ◽  
Pawan Singh ◽  
Sidharth Kashyap
Keyword(s):  
Dielectric Properties ◽  
Function Theory ◽  
Mode Frequency ◽  
Physical Parameters ◽  
Dihydrogen Phosphate ◽  
Thermal Dependence ◽  
Normal Mode Frequency ◽  
Coupled Mode ◽  
Dielectric Constant And Loss ◽  
Model Hamiltonian

Modified two sublattice pseudospin lattice coupled-mode model Hamiltonian has been applied to study the dielectric properties of deuterated cesium dihydrogen phosphate crystal. With the help of model Hamiltonian and Green’s function theory, the theoretical expressions for normal mode frequency, dielectric constant and loss tangent are derived. By fitting the model values of different physical parameters, the thermal dependence of the above quantities has been calculated. Our theoretical obtained results are well compared with experimental data.

scholarly journals An Experimental Study on the Dielectric Properties of Rubber Materials

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2908
Author(s):  
Hailong Chen ◽  
Yudong Xu ◽  
Mengqi Liu ◽  
Tao Li
Keyword(s):  
Experimental Study ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
Peak Frequency ◽  
Mixing Process ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Internal Mixing ◽  
Dielectric Constant And Loss

According to specific formulas, the mixing of rubber samples occurs by two methods: open mixing and internal mixing. The effects of frequency, mixing process, carbon black (CB) content, zinc oxide (ZnO) content, and stearic acid (SA) content on the dielectric properties of rubber materials were studied. The results showed that the effects of the mixing process on the dielectric properties of the rubber samples cannot be ignored, and the appropriate mixing process should be selected when preparing the required rubber materials. The dielectric constant and loss factor of the rubber samples vary depending on the frequency. The dielectric constant had a peak and valley value, while the loss factor only had a peak. The dielectric constant and loss factor of rubber samples were significantly affected by the content of CB, ZnO, and SA. The peak frequency decreased with the increase in CB content, however, the dielectric constant increased with an increase in CB content. The higher the ZnO content, the lower the peak frequency. In addition, the dielectric constant and loss factor increased with an increase in ZnO content. The higher the SA content, the greater the peak frequency. In addition, the dielectric constant and loss factor decreased with an increase in SA content. It is hoped that the experimental results obtained can provide guidance for the study of the dielectric properties, microwave absorption properties, and microwave heating characteristics of rubber polymers.

Dielectric Properties of β-SiAlON at High Temperature Using Perturbation Method

2008 ◽  
Vol 403 ◽  
pp. 121-123 ◽  
Author(s):  
Young Hoon Seong ◽  
Ha Neul Kim ◽  
Do Kyung Kim
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Dielectric Properties ◽  
Perturbation Method ◽  
Hot Pressing ◽  
Room Temperature ◽  
Tangent Loss ◽  
Resonator Method

-SiAlON with various z-values (z = 0.5~4.0) were produced by hot pressing. The dielectric properties (dielectric constant and tangent loss) of -SiAlON were characterized by the post-resonator method at room temperature and by the perturbation method from room temperature to 1200 oC at 2.45 GHz, respectively. Effect of z-values and temperatures with -SiAlON were investigated.

Study of ferroelectric lead monohydrogen phosphate type crystals

2017 ◽  
Vol 31 (32) ◽  
pp. 1750260 ◽  
Author(s):  
Aanchal Rawat ◽  
Trilok Chandra Upadhyay
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Function Method ◽  
Mode Frequency ◽  
Temperature Variations ◽  
Ferroelectric Transition ◽  
Coupled Mode ◽  
Dielectric Constant And Loss

In this paper, the ferroelectric transition and dielectric properties of the lead monohydrogen phosphate (PbHPO4) crystal are theoretically investigated. By using Green’s function method and modified two sublattice pseudospin–lattice coupled mode model, formulae for PbHPO4 type crystals are derived. Temperature variations of ferroelectric mode frequency, dielectric constant and loss tangent are calculated for the PbHPO4 crystal. Our results agree well with the experimental data.

Influence of Process Condition on the Dielectric Properties of CCTO-P(VDF-TrFE) 0-3 Composites

2011 ◽  
Vol 1312 ◽  
Author(s):  
Xiaobing Shan ◽  
Lin Zhang ◽  
Z.-Y. Cheng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
High Dielectric Constant ◽  
Process Condition ◽  
Hot Press ◽  
Ceramic Powders ◽  
Dielectric Constant And Loss ◽  
High Dielectric ◽  
Press Time ◽  
Hot Press Process

AbstractA high dielectric constant was observed in 0-3 composites using P(VDF-TrFE) copolymer as matrix and CaCu3TiO4 (CCTO) ceramic powders as fillers with a composition of 50 vol% CCTO. CCTO-P(VDF-TrFE) 0-3 composites with a CCTO content from 0 to 50 vol% were prepared and their dielectric properties, including frequency dependence and temperature dependence of the dielectric constant and loss, were characterized. It was experimentally observed that the hot-press process, inlcuding the configuration and hot-press time, has a strong influence on the dielectric properties of the composites. Additionally, the influence of the CCTO partice size on the dielectric properties of the composites was studied.

Effect of P2O5 on Microstructure and Properties of Calcium Aluminoborosilicate Glasses

2013 ◽  
Vol 538 ◽  
pp. 258-261
Author(s):  
X.H. Zhang ◽  
Y.L. Yue ◽  
H.T. Wu
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Dielectric Constant ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Dielectric Properties ◽  
Alkaline Earth ◽  
Chemical Durability ◽  
Tangent Loss ◽  
Structure And Properties ◽  
Weight Losses

In alkaline earth aluminoborosilicate glasses containing P2O5, the changes of structure and properties caused by variations in the ratio P2O5/B2O3were investigated. The structure was investigated by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The dielectric constant and tangent loss were measured at 1 MHz. Chemical durability was evaluated by weight losses of glass samples after immersion in water. The results indicated that the fraction of four-coordinated boron atoms (N4), chemical durability and dielectric properties increased with increasing P2O5/B2O3replacements.

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