Fabrication and Characterization of Colossal Dielectric Response of Polycrystalline Ca1-x SrxCu3Ti4O12 (0≤x≤1) Ceramics

2012 ◽  
Vol 1454 ◽  
pp. 81-87 ◽  
Author(s):  
Sung Yun Lee ◽  
Duk-Keun Yoo ◽  
Jihye Lee ◽  
William Jo ◽  
Youn-Woo Hong ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Response ◽  
Full Range ◽  
Complex Impedance ◽  
Lattice Parameter ◽  
Linear Increase ◽  
Lower Dielectric Constant ◽  
Second Phases ◽  
Fabrication And Characterization

ABSTRACTWe report the microstructures and dielectric properties of Ca1-xSrxCu3Ti4O12 (C1-xSxCTO, 0≤x≤1) ceramics sintered at the various sintering temperatures ranging from 1000 to 1060˚C in air. The linear increase in lattice parameter in C1-xSxCTO (0≤x≤1) ceramics is observable for the full range of substitution. However, the second phases of SrTiO3 and CuO start to occur from the composition of x=0.8, implying that a stoichiometric SrCu3Ti4O12 (SCTO) compound may not exist. While the C0.6S0.4CTO and C0.4S0.6CTiO samples exhibit relatively lower dielectric constant (εr) of ∼40,000 below 1 kHz, the CaCu3Ti4O12 (CCTO) and SCTO show the extremely high εr values of ~120,000 and ∼180,000, respectively. Complex impedance (Z*) and modulus (M*) spectroscopy revealed that the capacitance (C) and resistivity (ρ) values of grain boundary in all samples are much higher than those of grains.

scholarly journals Preparation and characterization of novel naphthyl epoxy resin containing 4-fluorobenzoyl side chains for low-k dielectrics application

RSC Advances ◽  
2017 ◽  
Vol 7 (85) ◽  
pp. 53970-53976 ◽  
Author(s):  
Tianyi Na ◽  
Hao Jiang ◽  
Liang Zhao ◽  
Chengji Zhao
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Side Chains ◽  
The Novel ◽  
Lower Dielectric Constant ◽  
Low K

The novel naphthyl epoxy resin was synthesized and cured with MeHHPA. It showed significantly lower dielectric constant and dielectric loss than other commercial epoxy resins due to the introduction of fluorine on the side chains.

Fabrication and Characterization of Electrically Functional Lanthanum Hexaboride Thin Films on Ultrasmooth Sapphire Substrates

2008 ◽  
Vol 1148 ◽  
Author(s):  
Yushi Kato ◽  
Yusaburo Ono ◽  
Yasuyuki Akita ◽  
Makoto Hosaka ◽  
Naoki Shiraishi ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam ◽  
Lattice Parameter ◽  
Lanthanum Hexaboride ◽  
Root Mean Square Roughness ◽  
Sapphire Substrates ◽  
Fabrication And Characterization ◽  
Laser Mbe ◽  
Atomically Flat

AbstractThe crystal growth of lanthanum hexaboride (LaB6) thin films was examined by applying the laser molecular beam epitaxy (laser MBE) process. C-axis (100) highly-oriented LaB6 thin films could be fabricated on ultrasmooth sapphire (α-Al2O3 single crystal) (0001) substrates with atomic steps of 0.2 nm in height and atomically flat terraces. The obtained film exhibited a smooth surface with root mean square roughness of 0.15 nm. The lattice parameter of the LaB6 thin film was close to the bulk value reported previously. In the case of deposition on commercial mirror-polished sapphire substrates, the grown film was amorphous. The resistivity of the prepared crystalline LaB6 thin films was as low as 2.2 × 10−4 Ω cm and almost constant in the temperature range of 10–300 K.

Fabrication and Characterization of Spin-On Silica Xerogel Films

1998 ◽  
Vol 511 ◽  
Author(s):  
S. Nitta ◽  
A. Jain ◽  
V. Pisupatti ◽  
W. N. Gill ◽  
P. C. Wayner ◽  
...  
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Convective Diffusion ◽  
Ambient Pressure ◽  
Silica Xerogel ◽  
High Porosity ◽  
Thermal Oxide ◽  
Fabrication And Characterization ◽  
Xerogel Films

ABSTRACTXerogel films of high porosity were fabricated using an ambient pressure technique. The same porosity can be obtained with different microstructures by varying the aging time of the films. The dielectric constant of these films as a function of porosity at 1 MHz follows correlations originally developed for bulk aerogels. Diffusion of copper is orders of magnitude faster in these xerogels than in the corresponding thermal oxide. An activation energy of 0.9 eV was estimated based on a convective diffusion model.

Potentialities of Nickel Oxide as Dielectric for GaN and SiC Devices

2013 ◽  
Vol 740-742 ◽  
pp. 777-780 ◽  
Author(s):  
Raffaella Lo Nigro ◽  
Giuseppe Greco ◽  
L. Swanson ◽  
G. Fisichella ◽  
Patrick Fiorenza ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Nickel Oxide ◽  
Electrical Characterization ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Lower Dielectric Constant ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition ◽  
Nio Films

This paper reports on a structural and electrical analysis of nickel oxide (NiO) films grown both on AlGaN/GaN heterostructures and on 4H-SiC epilayers. The films were grown by metal organic chemical vapor deposition (MOCVD). The structural analysis showed epitaxially oriented films over the hexagonal substrates. The electrical characterization of simple devices onto AlGaN/GaN heterostructures enabled to demonstrate a dielectric constant of 11.7 and a reduction of the leakage current in insulated gate structures. On the other hand, epitaxial NiO films grown onto 4H-SiC epilayers exhibited the presence of an interfacial SiO2layer and twinned NiO grains, and a lower dielectric constant.

The Influence of DC Bias on the Dielectric Response of Sr1-xCaxTiO3 Ceramics

2006 ◽  
Vol 514-516 ◽  
pp. 240-244
Author(s):  
Alexander Tkach ◽  
Branca Araújo ◽  
Paula M. Vilarinho
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Dielectric Response ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Average Grain Size ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Dc Bias ◽  
Microstructural Studies

The effect of the electric field on the dielectric response of the Sr1-xCaxTiO3 ceramic system was analysed and complemented by structural and microstructural studies. A monotonic decrease of the lattice parameter and an increase of the average grain size from 11 to 23 μm with increasing x were observed by X-ray diffraction and scanning electron microscopy analysis respectively. Samples with x = 0.003 and 0.01 reveal a monotonous increase of low-temperature dielectric constant, corresponding to an enhancement of the tunability and a reduction of the driving electric field at 10-30 K for x = 0.01. For Sr1-xCaxTiO3 ceramic samples with x = 0.04 and 0.10 the ferroelectric phase transition of around 20 K was observed together with the enhanced tunability of the dielectric constant at 30-85 K for x = 0.10.

Growth and Layer Characterization of SrTiO3 by Atomic Layer Deposition using Sr(tBu3Cp)2 and Ti(OMe)4

2009 ◽  
Vol 1155 ◽  
Author(s):  
Mihaela Popovici ◽  
Sven Van Elshocht ◽  
Nicolas Menou ◽  
Johan Swerts ◽  
Dieter Pierreux ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Atomic Layer Deposition ◽  
Crystalline State ◽  
Atomic Layer ◽  
Lattice Parameter ◽  
Index Of Refraction ◽  
Layer Deposition ◽  
Pulse Ratio

AbstractStrontium titanate (STO) thin films (45-67 % Sr) were deposited by atomic layer deposition using Sr(tBu3Cp)2/Ti(OMe)4/H2O as precursors. The Sr content of the layers is well controlled by the precursor pulse ratio, as indicated by Rutherford backscattering spectroscopy (RBS). The amount of Sr and Ti deposited depends on the Sr:Ti pulse ratio and indicates the enhancement of the Ti precursor reactivity in the presence of Sr-OH. STO compositions that are closer to stoichiometric SrTiO3 result in denser films with correspondingly higher index of refraction. The increase (decrease) of the Sr content over (below) 50 % leads to an expansion (contraction) of the lattice parameter corresponding to cubic SrTiO3 with a perovskite structure. The dielectric constant (extracted from film thickness series) and leakage current strongly depends both on the Sr content and the crystalline state of the films.

scholarly journals The dielectric constant of sandstones, 60 kHz to 4 MHz

Geophysics ◽  
1987 ◽  
Vol 52 (5) ◽  
pp. 644-654 ◽  
Author(s):  
Rosemary J. Knight ◽  
Amos Nur
Keyword(s):  
Dielectric Constant ◽  
Surface Area ◽  
Dielectric Response ◽  
Water Saturation ◽  
Pore Space ◽  
Strong Dependence ◽  
Complex Impedance ◽  
Volume Ratio ◽  
Electrode Polarization ◽  
Frequency Range

Complex impedance data were collected for eight sandstones at various levels of water saturation [Formula: see text] in the frequency range of 5 Hz to 4 MHz. The measurements were made using a two‐electrode technique with platinum electrodes sputtered onto the flat faces of disk‐ shaped samples. Presentation of the data in the complex impedance plane shows clear separation of the response due to polarization at the sample‐electrode interface from the bulk sample response. Electrode polarization effects were limited to frequencies of less than 60 kHz, allowing us to study the dielectric constant κ′ of the sandstones in the frequency range of 60 kHz to 4 MHz. κ′ of all samples at all levels of saturation shows a clear power‐law dependence upon frequency. Comparing the data from the eight sandstones at [Formula: see text], the magnitude of the frequency dependence was found to be proportional to the surface area‐to‐volume ratio of the pore space of the sandstones. The surface area‐to‐volume ratio of the pore space of each sandstone was determined using a nitrogen gas adsorption technique and helium porosimetry. κ′ also exhibits a strong dependence on [Formula: see text]. κ′ increases rapidly with [Formula: see text] at low saturations, up to some critical saturation above which κ′ increases more gradually and linearly with [Formula: see text]. Using the surface area‐to‐volume ratios of the sandstones, the critical saturation in the dielectric response was found to correspond to water coverage of approximately 2 nm on the surface of the pore space. Our interpretation of the observed dependence of κ′ on both frequency and [Formula: see text] is that it is the ratio of surface water to bulk water in the pore space of a sandstone that controls the dielectric response through a Maxwell‐Wagner type of mechanism.

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