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.

Dielectric Properties of Y3+-Doped Ba0.62Sr0.38TiO3 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 51-53
Author(s):  
Yuan Liang Li ◽  
Yuan Fang Qu ◽  
Feng Long Han ◽  
Chao Liu ◽  
Xiao Yan Li
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Dielectric Constants ◽  
Experimental Results ◽  
Dielectric Losses ◽  
Accelerate Growth ◽  
In The Beginning

Microstructure and dielectric properties of Ba0.62Sr0.38TiO3 ceramics doped with x mol% (x=0.2~0.6) Y2O3 were investigated. SEM showed that Y3+ can accelerate growth of the grains at first, then turn to inhabit growth of the grains with further addition of Y3+ above 0.8mol%. The experimental results showed that the dielectric constants were improved with the additive amount of Y3+ increasing, if the amount of Y3+ increased continuously, the dielectric constants will drop, whereas the dielectric losses of the samples descended rapidly in the beginning, then went up obviously with further addition of Y3+ above 1.0mol%, the optimal dielectric constant and dielectric loss could reach 6700 and 0.0015 in the room temperature, respectively.

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.

Comparative Study on Electrical and Dielectric Properties of Sintered Nano and Micro Silicon Nitride Ceramics

2016 ◽  
Vol 2 (1) ◽  
pp. 13-18
Author(s):  
Imran Khan ◽  
M S A Khan
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Silicon Nitride ◽  
Dc Conductivity ◽  
Temperature Range ◽  
Nitride Ceramics ◽  
Electrical And Dielectric Properties ◽  
Sintered Silicon

In the present work we have studied the electrical conductivity, dielectric constant and dielectric loss of Sintered Silicon Nitride ceramics. In this study it was found that the grain size has great impact on electrical conductivity and dielectric properties of Sintered Silicon Nitride Ceramics. The result shows more efficiency of electrical and dielectric properties with nano sized grains.  The sintering was performed in a programmable furnace at 950 K. The dc conductivity measured in the temperature range 300 K to 900 K. At higher temperature (T > 800 K), the dc conductivity increases exponentially with temperature for both of the investigated samples. Dielectric constant and loss are measured in the temperature range 300 K to 900 K with frequency range 1 KHz to 1 MHz. To confirm the grain size, the samples are characterized by the Scanning Electron Microscope (SEM). These types of samples can be used as a high temperature semi-conducting materials.

Dielectric Properties of Spray Deposited BaTiO3 and Ba0.68Sr0.32TiO3

2001 ◽  
Vol 698 ◽  
Author(s):  
Kipyung Ahn ◽  
Bruce W. Wessels ◽  
Robert Greenlaw ◽  
Sanjay Sampath
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Dielectric Constants ◽  
Second Phase ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Hvof Spray ◽  
Deposited Films

ABSTRACTThe microstructure and dielectric properties of BaTiO3 and Ba0.68Sr0.32TiO3 thick films deposited by thermal spray were investigated. The as-deposited films were predominantly crystalline with a small amount of an amorphous second phase. The as-deposited BaTiO3 films had dielectric constants as high as 240 at room temperature. Upon annealing in air at 500°C, the dielectric constant increased to 480. This increase in dielectric constant was attributed, in part, to the crystallization of the amorphous second phase. The stabilized phase depended on the spray process used. The high velocity oxy fuel (HVOF) spray process resulted in the deposition of paraelectric BaTiO3, whereas the plasma spray process resulted in the ferroelectric phase.

scholarly journals Preparation and studying Structural and Electrical properties of nano Co3O4

2019 ◽  
Vol 24 (6) ◽  
pp. 126
Author(s):  
Nawar Thamer Mohammed ◽  
Wasfi Mohammed Kadem
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electrical Properties ◽  
Sol Gel ◽  
Frequency Range ◽  
Nano Powder ◽  
Structural And Electrical Properties ◽  
Electrical And Dielectric Properties ◽  
Lcr Meter

In this study (Cobalt oxide) nano powder prepared using sol-gel method with a crystallite size 22 nm By testing XRD  and by matching with card (JCPDS) files No.( 00-042-1467). Electrical and dielectric properties like (Dielectric constant, resistivity, electrical conductivity) are studied by LCR meter with frequency range from (50 Hz) to (5 MHz ). It was noted that the resistivity and dielectric constant was decreasing while electrical conductivity increased with increased  frequency    http://dx.doi.org/10.25130/tjps.24.2019.118  

Epitaxial Growth and Anisotropic Dielectric Properties of La-Doped Bi4Ti3O12 Thin Films

2007 ◽  
Vol 124-126 ◽  
pp. 177-180
Author(s):  
Jang Sik Lee ◽  
Q.X. Jia
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bottom Electrode ◽  
Dielectric Constants ◽  
The Other ◽  
Field Range ◽  
Anisotropic Dielectric ◽  
Dielectric Nonlinearity ◽  
La Doped

To investigate the anisotropic dielectric properties of layer-structured bismuth-based ferroelectrics along different crystal directions, we fabricate devices along different crystal orientations using highly c-axis oriented Bi3.25La0.75Ti3O12 (BLT) thin films on (001) LaAlO3 (LAO) substrates. Experimental results have shown that the dielectric properties of the BLT films are highly anisotropic along different crystal directions. The dielectric constants (1MHz at 300 K) are 358 and 160 along [100] and [110], respectively. Dielectric nonlinearity is also detected along these crystal directions. On the other hand, a much smaller dielectric constant and no detectable dielectric nonlinearity in a field range of 0-200 kV/cm are observed for films along [001] when c-axis oriented SRO is used as the bottom electrode.

scholarly journals Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

2021 ◽  
Vol 16 (2) ◽  
pp. 138-147
Author(s):  
S. A. Syrbu ◽  
M. S. Fedorov ◽  
E. A. Lapykina ◽  
V. V. Novikov
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Anisotropy ◽  
Specific Electrical Conductivity ◽  
Conductivity Anisotropy ◽  
Independent Molecules ◽  
System Properties ◽  
The Individual

Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %. 

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.

Study the physical, electrical and dielectric properties of calcium doped Ni–Zn ferrites

2019 ◽  
Vol 33 (12) ◽  
pp. 1950145 ◽  
Author(s):  
M. A. A. Nooman ◽  
M. N. I. Khan ◽  
S. D. Hossain ◽  
M. F. Hossain ◽  
M. A. Samad ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Spinel Phase ◽  
Nominal Composition ◽  
Thermally Activated ◽  
Composition Formula ◽  
Zn Ferrite ◽  
Mobility Of Charge Carriers ◽  
Electrical And Dielectric Properties ◽  
Calcium Doped

Calcium doped Ni–Zn ferrites having the nominal composition [Formula: see text] (x = 0, 0.1, 0.2, 0.3 and 0.4) are prepared via the conventional ceramic method at [Formula: see text] for 3 h to study their physical, electrical and dielectric properties at high frequencies which have extended their applications. The X-ray diffraction (XRD) and scanning electron microscope (SEM) have been used to characterize the microstructure and surface morphology of the prepared composition. XRD patterns reveal the formation of pure spinel phase ferrites whereas SEM micrographs display nonhomogeneous grains of polyhedral shape. The studies disclose that with increasing Ca content in spinel, the lattice parameter of the Ni–Zn ferrite increases and at the same time the grain boundary also increases. As a result of the increased boundary, the large grains could be trapped pores inside the grains which have affected the density, resistivity and dielectric constant of the sample. The DC electrical resistivity of the prepared sample decreases with the increase of Ca content. Also, the resistivity decreases with increasing the temperature. This increase in the conductivity with temperature must be regarded mainly as due to the thermally activated mobility of charge carriers, but not to a thermally activated creation of these carriers. The dielectric constant decreases with the increasing frequency following the Verway-de-Boer hopping mechanism.

Pulsed Laser Deposition of BaxSr1−xTiO3 Films on MgO, LaAlO3 and SrTiO3 for Tunable Microwave Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
Wontae Chang ◽  
James S. Horwitz ◽  
Won-Jeong Kim ◽  
Jeffrey M. Pond ◽  
Steven W. Kirchoefer ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electric Field ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Dielectric Constants ◽  
Laser Deposition ◽  
Film Stress ◽  
Donor Acceptor ◽  
Bst Films

AbstractSingle phase BaxSr1−xTiO3 (BST) films (∼0.5-7 μm thick) have been deposited onto single crystal substrates (MgO, LaAlO3, SrTiO3) by pulsed laser deposition. Silver interdigitated electrodes were deposited on top of the ferroelectric film. The room temperature capacitance and dielectric Q (1/tanδ) of the film have been measured as a function of electric field (≤80 kV/cm) at 1 - 20 GHz. The dielectric properties of the film are observed to strongly depend on substrate type and post-deposition processing. After annealing (≤1000° C), it was observed that the dielectric constant and % tuning decreased and the dielectric Q increased for films deposited onto MgO, and the opposite effect was observed for films deposited onto LaA1O3. Presumably, this change in dielectric properties is due to the changes in film stress. Very thin (∼50 Å) amorphous BST films were successfully used as a stress-relief layer for the subsequently deposited crystalline BST (∼5000 Å) films to maximize % tuning and dielectric Q. Films have been deposited from stoichiometric targets and targets that have excess Ba and Sr. The additional Ba and Sr has been added to the target to compensate for deficiencies in Ba and Sr observed in the deposited BST (x=0.5) films. Films deposited from compensated targets have higher dielectric constants than films deposited from stoichiometric targets. Donor/acceptor dopants have also been added to the BST target (Mn, W, Fe ≤4 mol.%) to further improve the dielectric properties. The relationship between the dielectric constant, the dielectric Q, the change in dielectric constant with electric field is discussed.

Sign in / Sign up

Export Citation Format

Share Document