Dielectric permittivity in the x-ray region

1978 ◽  
Vol 126 (11) ◽  
pp. 479-513 ◽  
Author(s):  
A.V. Kolpakov ◽  
V.A. Bushuev ◽  
R.N. Kuz'min
Keyword(s):  
Dielectric Permittivity ◽  
X Ray

scholarly journals Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4017
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Ceramic Materials ◽  
Sintering Behavior ◽  
Terahertz Time Domain Spectroscopy ◽  
Very High Frequency ◽  
X Ray ◽  
Low Dielectric ◽  
Very High

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

HIGH THERMAL STABILITY OF MICROWAVE DIELECTRIC PROPERTIES OF CaTi1-x(Nb1/2Fe1/2)xO3 CERAMICS

2011 ◽  
Vol 01 (04) ◽  
pp. 417-427 ◽  
Author(s):  
A. D. S. BRUNO COSTA ◽  
M. C. ROMEU ◽  
R. C. S. COSTA ◽  
T. S. M. FERNANDES ◽  
F. W. DE O. AMARANTE ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Solid Solutions ◽  
Microwave Dielectric Properties ◽  
Titanium Content ◽  
Milling Process ◽  
Solid State Method ◽  
Small Shift ◽  
X Ray ◽  
Microwave Dielectric

This paper presents a study of the structure and microwave properties of [Formula: see text] substituted into the Ti 4+ site of calcium titanate ceramics. The structural and dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, was done. The microwave dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, (CNFTOX with x = 0.1 to x = 1) is discussed. The modified CaTiO3 (CTO) ceramics were prepared by a new procedure in the solid-state method. A study of the variations of the ball-milling process was done. The calcinations were done at 900°C for 3 and 5 h respectively, and the sintering at 1100°C, for 3 h. The structural property studies of the ceramics were investigated by X-ray diffraction (XRD) and Raman spectroscopy. The X-ray analysis showed that all samples have an orthorhombic structure. The refinement analysis of all samples were also duly performed and discussed. The nine scattering bands centered at 183, 227, 247, 288, 338, 470, 490 and 805 cm-1 were observed. Several peaks presented a small shift as a function of the x value. All Raman spectra in the studied samples showed a small band at 805 cm-1, which is a function of the x value. The dielectric permittivity and loss at microwave frequencies (MW) were investigated. For both calcination treatments (900°C for 3 and 5 h), the dielectric permittivity decreased with a decrease of the titanium content. Dielectric permittivity values in the range of 20 to 80 were obtained. It was also observed that a higher number of balls in the milling process contribute to the increase of the εr values. The CNFTO has an excellent microwave property at x = 0.6, with a temperature coefficient of resonant frequency (τf) near zero (τf = 2.8 ppm/°C).

Preparation and Characterization of Polymer Blends of Ethyl Cellulose and its Composites

2013 ◽  
Vol 665 ◽  
pp. 336-340 ◽  
Author(s):  
Eknath Nivrtirao ◽  
Basavaraja Sannakki
Keyword(s):  
Activation Energy ◽  
Dielectric Permittivity ◽  
Polymer Blend ◽  
Ethyl Cellulose ◽  
Weight Percent ◽  
Vinyl Pyrrolidone ◽  
X Ray ◽  
Poly Vinyl Pyrrolidone ◽  
Different Thickness

The polymer blend of Ethyl Cellulose (EC) with Poly (vinyl) pyrrolidone (PVP) of various weight percentages at different thickness are used for measurement of dielectric permittivity, electrical conductivity and optical properties. The activation energies of the EC and its blend with PVP are obtained through measurement of dc conductivity. The samples are characterized by using X-ray diffractometer (XRD). The blends of EC with PVP in the ratio of 50:50 weight percent using FTIR over the range of wavenumber 4000-500 cm-1. Key words: Polymer Blend, XRD, SEM, FTIR, dielectric permittivity, activation energy.

scholarly journals Crystal Structure and Dielectric Property of Endohedral Lithium Fullerene

2014 ◽  
Vol 70 (a1) ◽  
pp. C195-C195
Author(s):  
Shinobu Aoyagi ◽  
Kunihisa Sugimoto ◽  
Hiroshi Okada ◽  
Norihisa Hoshino ◽  
Tomoyuki Akutagawa
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Dielectric Property ◽  
Low Temperature ◽  
Dielectric Permittivity ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Structure Analysis ◽  
X Ray ◽  
Dielectric Phase

Endohedral lithium fullerene Li+@C60 can have a dielectric polarization by the off-centered location of the Li+ cation inside the C60 cage. The x-ray structure analysis of the PF6– salt [Li@C60](PF6) revealed that the Li+ cation occupies two off-centered equivalent positions at 20 K and hence the crystal is non-polar [1]. The disordered structure at low temperature is explained by a static orientation disorder of polar Li+@C60 cations and/or a dynamic tunneling of the Li+ cation inside the C60 cage. The Li+ tunneling would be suppressed by an intermolecular interaction at lower temperature and a dielectric phase transition might be induced. We reveal the dielectric property and crystal structure of [Li@C60](PF6) below 20 K in this study. The temperature dependence of the dielectric permittivity was measured for the single crystal down to 9 K. The dielectric permittivity increases with decreasing temperature according to the Curie-Weiss law. Such a behavior was also observed in H2O@C60 crystal but not in empty C60 crystal [2]. No dielectric phase transition was observed in H2O@C60 down to 8 K. In contrast, a dielectric anomaly suggesting a phase transition was observed in [Li@C60](PF6) around 18 K. The single-crystal x-ray diffraction experiment below 20 K was also performed at SPring-8 BL02B1. The crystal has a cubic structure at 20 K [1]. The temperature dependence of the cubic lattice constant shows no anomaly around 18 K. However, diffraction peaks that are forbidden for the given structure appear below 18 K. Thus the crystal symmetry is lowered by the dielectric phase transition. We present the result of the crystal structure analysis of the newly discovered low-temperature phase.

scholarly journals DIELECTROMETRIC STUDY OF RADIATION PROTECTION ABILITY OF ULTRA-DISPERSED NANODIAMONDS

2021 ◽  
pp. 187-195
Author(s):  
Liliya Batyuk ◽  
Nataliya Kizilova
Keyword(s):  
Dielectric Permittivity ◽  
Radiation Protection ◽  
Blood Cells ◽  
Tumor Development ◽  
Relaxation Frequency ◽  
Control Group ◽  
Dielectric Parameters ◽  
X Ray ◽  
Body Tissues ◽  
Guerin’S Carcinoma

Radiation protection ability of the ultra-disperse nanodiamonds (UDD) is studied based on the measurements of dielectric permittivity of red blood cells (RBC) affected by cancer. Wistar rats with Guerin's carcinoma were treated by X-ray 5.8 Gy. Some rats received UDD with food during 5 days prior to the X-ray. The groups with UDD, X-ray, and both UDD and X-ray treatments were compared to the control group. The complex dielectric permittivity of the RBC was measured by microwave dielectrometry. It was shown, tumor development leads to the increase in the dielectric permittivity and relaxation frequency. The irradiation promotes further growth of the parameters, while UDD uptake leads to insignificant changes in comparison to the control group. Therefore, UDD occur the radioprotective effect promoting repair, compensation and restoration of body tissues that is demonstrated by normalization of the dielectric parameters of RBC.

scholarly journals Optical Microscopy, X-Ray Diffraction, and Dielectric Permittivity Studies in Binary Mixtures of Nematogens Showing Induced Smectic Phase

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Suchismita Datta Sarkar ◽  
Basana Choudhury
Keyword(s):  
Dielectric Permittivity ◽  
Optical Microscopy ◽  
Binary Mixtures ◽  
Phase Region ◽  
Smectic Phase ◽  
Dielectric Anisotropy ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
X Ray ◽  
Static Dielectric Permittivity

The binary mixtures of nematogenic compounds 4-n-pentyl phenyl 4-n′-hexyloxy benzoate (ME6O.5) and 4-cyanophenyl 4-heptyl benzoate (CPHB) show the presence of induced smectic phase. In the present paper we report the phase diagram of the binary system (ME6O.5+CPHB) obtained by polarizing optical microscopy as well as the results of X-ray diffraction and static dielectric permittivity measurements on the system throughout the entire composition range. The observed variation of dielectric anisotropy with molar concentration in the induced smectic phase region is explained by assuming molecular associations in the mixture which is supported by our measurements of layer spacing in the induced smectic phase by X-ray diffraction studies.

Dielectric permittivity in the x-ray region

1978 ◽  
Vol 21 (11) ◽  
pp. 959-977 ◽  
Author(s):  
A V Kolpakov ◽  
V A Bushuev ◽  
R N Kuz'min
Keyword(s):  
Dielectric Permittivity ◽  
X Ray

Preparation of Na0.5K0.5NbO3/La0.6Sr0.2Mn1.2O3/LaAlO3 Thin Film Structures by Pulsed Laser Deposition

1999 ◽  
Vol 574 ◽  
Author(s):  
Choong-Rae Cho ◽  
S. I. Khartsev ◽  
A. M. Grishin ◽  
Ture Lindbäick
Keyword(s):  
Dielectric Permittivity ◽  
Room Temperature ◽  
Single Phase ◽  
Pulsed Laser ◽  
Dissipation Factor ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Tan Δ

AbstractWe report on ferroelectric/giant magnetoresistive Na0.5K0.5NbO3/La0.6Sr0.2Mn1.2O3 (NKN/LSMO) heterostructures grown onto LaAlO3 (001) single crystal using KrF pulsed laser ablation of stoichiometric ceramic target. Main processing parameters have been optimized to obtain smooth LSMO template layer, avoid NKN-LSMO interdiffusion, preserve NKN stoichiometry against the lost of volatile potassium and sodium and achieve reasonable reliability of NKN film performance. X-ray diffraction θ- 2θ scans and rocking curves evidence for single-phase content and high c-axis orientation both in template LSMO and top NKN layers. Ferroelectric measurements yield remnant polarization Pr of 1.5 [C/cm2 and spontaneous polarization Ps of 7 μC/cm2 at electric field strength of 130 kV/cm. At room temperature, dielectric permittivity ε′ and dissipation factor tan δ have been found to vary from 595 to 555 and 0.046 to 0.029 respectively in the frequency range of 0.4 to 20 kHz. At 10 kHz dielectric permittivity linearly increases from 410 to 650 in the temperature range 77 K to 415 K while the dissipation factor below 320 K does not exceed 3%.

Structure and electrophysical properties of polyvinylidene fluoride (PVDF)/magnetite nanocomposites

2018 ◽  
Vol 33 (1) ◽  
pp. 138-149 ◽  
Author(s):  
MA Ramazanov ◽  
AM Maharramov ◽  
HA Shirinova ◽  
Luca Di Palma
Keyword(s):  
Dielectric Permittivity ◽  
Polyvinylidene Fluoride ◽  
Vinylidene Fluoride ◽  
Theoretical Calculations ◽  
Threshold Value ◽  
Electrophysical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Subsequent Decrease ◽  
Poly Vinylidene Fluoride

In the present study, the effect of magnetite (Fe3O4) nanoparticles on the structural and dielectric properties of poly(vinylidene fluoride) (PVDF) matrix was investigated. Distribution of Fe3O4 nanoparticles in the polymer matrix has been studied by scanning electron microscopy (JEOL JSM-7600 F). The structure of the nanocomposite samples was investigated by the X-ray diffraction and Fourier-transform infrared spectroscopy. It was shown that the dielectric permittivity of PVDF + Fe3O4 nanocomposite samples was gradually increased up to 7 wt% of Fe3O4 content. Further increase in the concentration of the filler leads to decrease in the dielectric permittivity. The subsequent decrease in dielectric permittivity at higher Fe3O4 content can be explained by the increase in defects in the structure of the nanocomposite. The comparison of experimental data and the results of theoretical calculations show that the reduction in the empirical value of dielectric permittivity of the nanocomposite is obviously linked with the threshold value of filler. While calculating the theoretical value of the dielectric permittivity for the higher content of the filler, defects in the nanocomposite structure should be considered.

γ-Irradiation Stimulated Change of Recycled Polypropylene Composites Dielectric Permittivity

2006 ◽  
Vol 969 ◽  
Author(s):  
Ulmas Gafurov ◽  
Z. Fazilova
Keyword(s):  
Dielectric Permittivity ◽  
Thermoplastic Composites ◽  
Formation Processes ◽  
X Ray Diffraction ◽  
Degree Reduction ◽  
Γ Irradiation ◽  
Crystallinity Degree ◽  
X Ray ◽  
Polypropylene Composites ◽  
Recycled Polypropylene

AbstractThe γ-irradiation influence on dielectric permittivity (ε′) of recycled polypropylenes (PPR) and of thermoplastic composites γV TDV on its bases has been investigated. It was investigated follows thermoplastic composites: PPR+EPDM, PPR+EPDM+GTR, PPR+EPDM+GTR/plast; EPDM -ethylene-propylene diamine. The permittivity increasing up to dose ∼ 100 kGy one can explained of radiation stimulated peroxide radicals formation, processes of cross-linking and increase of ordering, crystallinity degree. It is supported the measurements of the IR spectra of irradiated samples and by the data of X-ray diffraction measurements.The dielectric permittivity for the PPR+EPDM and PPR+EPDM+GTR/plast composites have little change up to the dose of γ-irradiated 1500 kGy and the composites have stable dielectric properties. The stable properties is defined the radiation stable of polymer (PPR) matrix. The dose raise more lead to the permittivity decreasing for the plasticized composite PPR+EPDM+GTR/plast. It is result of crystallinity degree reduction and by plasticization of destruction products.

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