THE DIELECTRIC PROPERTIES OF METHANOL AND METHANOL-d

1957 ◽  
Vol 35 (5) ◽  
pp. 458-473 ◽  
Author(s):  
D. W. Davidson
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Freezing Point ◽  
Relaxation Times ◽  
Dielectric Constants ◽  
Gradual Transition ◽  
Kcal Mole ◽  
Limited Temperature ◽  
Limited Temperature Range ◽  
Static Dielectric Constants

The dielectric properties of methanol and methanol-d were examined between liquid nitrogen and room temperature at frequencies between 40 and 106 cycles per second. In addition to the large increase in the dielectric constant within solid CH3OH at 159.6°K., there is evidence of a further, gradual transition at about 155°K. Similar changes in CH3OD occur at 163.2° and about 157°K. Dispersion processes within the solid are discussed in terms of misaligned crystallites and polarization at the interfaces between crystallites and between regions of solid and liquid. Conductance maxima near 130°K. are tentatively related to the methanol–water eutectic. Static dielectric constants of liquid CH3OD are a little lower than those of CH3OH, while relaxation times over a limited temperature range above the freezing point are some 35% higher; the activation energies for dielectric relaxation of the two molecules in the liquid state are approximately the same (3.5 kcal./mole).

New Perovskite Nanomaterials and Their Integrations into High-k Dielectrics

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000072-000077
Author(s):  
Minoru Osada ◽  
Takayoshi Sasaki
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Bottom Electrode ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Layered Perovskite ◽  
Layer By Layer ◽  
High K ◽  
High K Dielectric ◽  
High Dielectric

We report on a bottom-up manufacturing for high-k dielectric films using a novel nanomaterial, namely, a perovskite nanosheet (LaNb2O7) derived from a layered perovskite by exfoliation. Solution-based layer-by-layer assembly of perovskite nanosheets is effective for room-temperature fabrication of high-k nanocapacitors, which are directly assembled on a SrRuO3 bottom electrode with an atomically sharp interface. These nanocapacitors exhibit high dielectric constants (k > 50) for thickness down to 5 nm while eliminating problems resulting from the size effect. We also investigate dielectric properties of perovskite nanosheets with different compositions (LaNb2O7, La0.95Eu0.05Nb2O7, and Eu0.56Ta2O7) in order to study the influence of A- and B-site modifications on dielectric properties.

Structural and dielectric properties of Bi2NbxVi−xO5.5 ceramics

1996 ◽  
Vol 11 (9) ◽  
pp. 2288-2292 ◽  
Author(s):  
K. B. R. Varma ◽  
K. V. R. Prasad
Keyword(s):  
Differential Scanning Calorimetry ◽  
Grain Size ◽  
Dielectric Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Dielectric Constants ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Bi2Nbx V1−xO5.5 ceramics with x ranging from 0.01 to 0.5 have been prepared. The crystal system transforms from an orthorhombic to tetragonal at x 3= 0.1 and it persists until x = 0.5. Scanning electron microscopic (SEM) investigations carried out on thermally etched Bi2NbxV1−xO5.5 ceramics confirm that the grain size decreases markedly (18 μm to 4 μm) with increasing x. The shift in the Curie temperature (725 K) toward lower temperatures, with increasing x, is established by Differential Scanning Calorimetry (DSC). The dielectric constants as well as the loss tangent (tan δ) decrease with increasing x at room temperature.

Effect of Ti Content on Microstructure and Dielectric Properties of Li and Ti Co-Doped NiO Thin Films

2007 ◽  
Vol 336-338 ◽  
pp. 2639-2642 ◽  
Author(s):  
Ya Ru Zhang ◽  
Bo Ping Zhang ◽  
Yan Dong ◽  
Jing Feng Li
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Coating Method ◽  
Diffraction Peaks ◽  
Ti Content ◽  
Ti Doping ◽  
Co Doped

Li and Ti co-doped NiO thin films with 200 nm in thickness were deposited onto Pt/Ti/SiO2/ Si(100) substrates using a sol-gel spin-coating method. The effect of Ti doping content on microstructure and dielectric properties of Li0.10TixNi0.90-xO (x=5-20mol%) thin films was investigated. XRD results showed that all the Li0.10TixNi0.90-xO thin films consisted of a mixture of NiO, Li2NiO2 and NiTiO3 oxides. The intensities of the diffraction peaks for the NiTiO3 phase increased and those for NiO decreased with increasing Ti content, suggesting that a part of NiO phase combined with Ti to form NiTiO3 phase. The dielectric constants of all the Li0.10TixNi0.90-xO thin films at 102 Hz at room temperature ranged from 200 to 400 and increased with increasing Ti content. The frequency stability of the dielectric constant for the Li0.10TixNi0.90-xO thin films was also improved greatly with increasing Ti content.

Preparation and Dielectric Properties of Cu/PVDF Composite Films

2014 ◽  
Vol 1035 ◽  
pp. 417-421 ◽  
Author(s):  
Jian Wen Zhai ◽  
Ya Jun Wang ◽  
Jian Lou Deng ◽  
Chang Gen Feng
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Composite Films ◽  
Interfacial Polarization ◽  
Dielectric Constants ◽  
Pvdf Film ◽  
Continuous Increase ◽  
Better Than

nanoand micro size Cu were employed separately and investigated comparatively. Different volume fraction of Cu was added into PVDF film in order to investigate the content of filler effect on the dielectric properties of polymer composites. XRD and SEM were used to analyze the crystalline phase and microstructure of the films. The results show that two sizes of Cu have the same peak features, and with the continuous increase of the content of Cu, it disperse better in PVDF. The dielectric constant (ε) of the composite containing 16 vol% micro-CCTO filler is 16 at 100 Hz and room temperature, and its dielectric loss (tanδ) is only 0.15, which is substantially better than others. Besides, for 18 vol% nanoCu/PVDF composite tanδis 0.25 andεis 18 at 100 Hz. Moreover,εand tanδof nanoCu/PVDF composite are both higher than those of micro-Cu/PVDF. Analysis shows that the composites with nanoCu have higher dielectric constants, which is mainly from the interfacial polarization.

High-Temperature Dielectric Properties of Polycrystalline Ceramics

1988 ◽  
Vol 124 ◽  
Author(s):  
W. W. Ho
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Volume Expansion ◽  
Room Temperature ◽  
Experimental Methods ◽  
Dielectric Constants ◽  
Amorphous Phases ◽  
Temperature Loss ◽  
Polycrystalline Ceramics ◽  
Impurity Doping

ABSTRACTExperimental methods for determining the high-temperature millimeter-wave dielectric properties of solids are described and the data obtained on a wide variety of polycrystalline ceramics are reviewed. In general, the observed increase in dielectric constants with temperature can be modeled with a macroscopic dielectric virial expansion and shown to be primarily caused by an increase in polarizability due to volume expansion. The room-temperature loss tangents in low-absorption ceramics are probably caused by impurity doping of the primary and secondary crystalline phases at grain junctions and along grain boundaries. The rapid increase in loss tangent at high temperatures commonly observed in polycrystalline ceramics is associated with softening of intergranular amorphous phases resulting in an increase in localized electrical conductivity.

scholarly journals Porous and Nonporous Film-Shaped Magnetorheological Nanocomposites: Dielectric and Electrical Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Aref Naimzad ◽  
Yousef Hojjat ◽  
Mojtaba Ghodsi
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Volume Resistivity ◽  
Comparative Investigation ◽  
Dielectric Constants ◽  
Dielectric Losses ◽  
Iron Particles ◽  
Electrical And Dielectric Properties

This paper presents a brief experimental comparative study on electrical and dielectric properties of two sets of porous and nonporous MRNCs, each including five samples of film-shaped magnetorheological nanocomposites (MRNCs) based on room temperature vulcanized (RTV) silicone rubber and nanosized carbonyl iron particles (CIPs). The electrical and dielectric properties of porous and nonporous MRNCs were measured at five different filler concentrations. Several experiments were performed to measure the volume resistivity, dielectric constant, and dielectric loss. The MRNCs dielectric properties were analysed with respect to the parameters like frequency and CIPs loadings. The electrical conductivity was studied in terms of volume resistivity. The comparative investigation suggests the porous MRNCs for smart and light-weighted structures those benefits from a lower electrical property, dielectric losses, and dielectric constants.

scholarly journals Molecular Interactions and Dielectric Relaxation in the Mixtures of Amines with 2-Fluorobenzoic Acid in 1, 4-Dioxane

2019 ◽  
Vol 9 (1) ◽  
pp. 2866-2870
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Angular Frequency ◽  
Dielectric Constants ◽  
Intramolecular Interactions ◽  
Dielectric Parameters ◽  
Molar Ratios ◽  
Group Rotation ◽  
Static Dielectric Constants

For the present study, the estimation of the static dielectric constants (0 ), dielectric constant () at an angular frequency and dielectric loss () of methyl, ethyl and propyl amines with 2-fluorobenzoic acid in 1,4-dioxane were carried using Klystron microwave bench at frequency 9.43GHz. Using the dielectric parameters, the overall relaxation time (1 ) and group rotation relaxation time (2 ) of the polar solute molecules and average relaxation times (0 ) were also determined using Higasi and Gopalakrishna method employing Debye’s equations. The obtained results revealed that, out of five different molar ratios, relaxation time () is maximum at 1:1 molar concentration for all the systems due to inter and intramolecular interactions through hydrogen bonding. In addition, the dipole moment, activation viscous flow (f) and dielectric relaxation (f ) due to molar free energy also been discussed.

Dielectric Properties of Y2NiMnO6 Ceramics at Various Sintering Times and Temperatures

2015 ◽  
Vol 804 ◽  
pp. 16-20 ◽  
Author(s):  
Panakamon Deeyai ◽  
Thanapong Sareein ◽  
Bundit Putasaeng ◽  
Naphat Chathirat
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Dielectric Constants ◽  
The Other ◽  
Other Hand ◽  
Low Sintering Temperature ◽  
Sintering Conditions

Dielectric properties of hydrothermally decomposed Y2NiMnO6 ceramics prepared under several sintering conditions were investigated at room temperature. As the results, dielectric constants at 200 Hz were found about 928 and 23x103 for samples sintered at 1000 and 1400 oC, respectively. The dielectric permittivity for samples sintered at 1400 oC for different sintering times from 6 to 24 hours have yielded the best dielectric permittivity value of 104. On the other hand, low sintering temperature had resulted in smaller dielectric loss in comparison to larger dielectric loss generally found in the ceramics with high sintering temperature.

Dielectric Relaxation and Intramolecular Rotation in Aliphatic Ketones

1973 ◽  
Vol 51 (16) ◽  
pp. 2671-2675 ◽  
Author(s):  
John Crossley
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Dielectric Constants ◽  
Aromatic Ketones ◽  
Paraffin Oil ◽  
Aliphatic Ketones ◽  
Intramolecular Rotation ◽  
Static Dielectric Constants ◽  
Viscosity Dependence

Dielectric constants and losses have been obtained for a number of aliphatic and aromatic ketones in cycloexane, n-hexadecane, decalin and paraffin oil – cyclohexane mixtures at up to ten frequencies between 1 and 145 GHz at 25 °C. Static dielectric constants have also been measured at 2 MHz. The results for each system have been analyzed in terms of a Cole–Cole distribution. The relaxation times and their viscosity dependence are discussed in terms of dipole reorientation by intramolecular and whole molecule rotations.

scholarly journals Dielectric Properties of (CdSe)1-X(ZnS)X Mixed Semiconductor Compounds

2012 ◽  
Vol 9 (2) ◽  
pp. 179-189 ◽  
Author(s):  
K. YADAIAH ◽  
J. KRISHNAIAH ◽  
VASUDEVA REDDY ◽  
M. NAGABHUSHANAM
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Relaxation Times ◽  
Dielectric Constants ◽  
Semiconductor Materials ◽  
Precipitation Method ◽  
Semiconductor Compounds ◽  
Optical Dielectric ◽  
Co Precipitation

Dielectric permittivity has been an important property of binary and mixed semiconductor materials as it is closely related to the studies on polarization and relaxation mechanisms. Therefore, dielectric properties of (CdSe)1-X(ZnS)X mixed semiconductors are studied at different frequencies. The mixed semiconductor samples used in the study are grown by controlled co-precipitation method. From these studies ac conductivity, static and optical dielectric constants, relaxation times and activation energy of dipole relaxation are determined. The variation of dielectric constant with frequency and composition of the sample was explained on the basis of Koops grain boundary mechanism.

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