Dielectrics

Four compositions in the Sr1–3x/2CexTiO3 homologous series, corresponding to x ) 0.1333, 0.1667,
0.25, and 0.4, have been produced by conventional solid-state processing. The structure of these compounds
was analyzed by X-ray, electron, and neutron diffraction. While no superlattice can be observed via
X-ray diffraction, both electron and neutron diffraction show evidence of a noncubic supercell caused by
antiphase tilting of oxygen octahedra. The most likely space group is R3j
c, corresponding to an a-a-atilt
system, except for the composition x ) 0.4, for which an even more complex superstructure is observed.
The degree of tilt increases with increasing x.

Microwave dielectric ceramics based on RETiTaO6 (RE = La, Cc, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, Al, and In) were prepared using a conventional solid-state ceramic route. The structure and microstructure of the samples were analyzed using x-ray diffraction and scanning electron microscopy techniques. The sintered samples were characterized in the microwave frequency region. The ceramics based on Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy, which crystallize in orthorhombic aeschynite structure, had a relatively high dielectric constant and positive τf while those based on Ho, Er, and Yb, with orthorhombic euxenite structure, had a low dielectric constant and negative τf. The RETiTaO6 ceramics had a high-quality factor. The dielectric constant and unit cell volume of the ceramics increased with an increase in ionic radius of the rare-earth ions, but density decreased with it. The value of τf increased with an increase in RE ionic radii, and a change in the sign of τf occurred when the...

Cerium oxide (CeO2) has been prepared as a ceramic dielectric resonator by a conventional solid-state ceramic route. The sintered CeO2 has a high dielectric quality factor (Q×f), Q value of 10 000 at 6 GHz with a relative permittivity (ε′) of 23, and temperature coefficient of resonant frequency (τf of -53 ppm/°C. The Q value increases to 20 000 at 6 GHz when the CeO2 is doped with 1 mol% CaCO3. Higher levels of CaCO3 doping lowers the Q and ε′ values and simultaneously decreases τf. TiO2 doping decreases τf and slightly increases ε′, but deceases the Q value. The Q value of pure CeO2 increases to 105 000 at a frequency of 5.58 GHz when it is cooled to 30 K, whereas Q ≈ 85 000 at 5.48 GHz for 1-mol%-CaCO3-doped CeO2 at 30 K.

In this paper, we propose an approach to the problem of simultaneous shape and refractive index recovery from multispectral polarisation imagery captured from a single viewpoint. The focus of this paper is on dielectric surfaces which diffusely polarise light transmitted from the dielectric body into the air. The diffuse polarisation of the reflection process is modelled using a Transmitted Radiance Sinusoid curve and the Fresnel transmission theory. We provide a method of estimating the azimuth angle of surface ...

The formation of solid solutions of the type [Ba(HOC2H4OH)4][Ti1−x Gex (OC2H4O)3] as Ba(Ti1−x /Gex )O3 precursors and the phase evolution during thermal decomposition of [Ba(HOC2H4OH)4][Ti0.9Ge0.1(OC2H4O)3] (1) are described herein. The 1,2-ethanediolato complex 1 decomposes above 589 °C to a mixture of BaTiO3 and BaGeO3. A heating rate controlled calcination procedure, up to 730 °C, leads to a nm-sized Ba(Ti0.9/Ge0.1)O3 powder (1a) with a specific surface area of S = 16.9 m2/g, whereas a constant heating rate calcination at 1,000 °C for 2 h yields a powder (1b) of S = 3.0 m2/g. The shrinkage and sintering behaviour of the resulting Ba(Ti0.9/Ge0.1)O3 powder compacts in comparison with nm-sized BaTiO3 powder compacts (2a) has been investigated. A two-step sintering procedure of nm-sized Ba(Ti0.9/Ge0.1)O3 compacts (1a) leads, below 900 °C, to ceramic bodies with a relative density of ≥90%. Furthermore, the cubic ⇆ tetragonal phase transition temperature has been detected by dilatometry, and the temperature dependence of the dielectric constant (relative permittivity) has also been measured.

SrLa2Mg2W2O12 and Sr2La2MgW2O12 ceramics were prepared
by the conventional solid-state ceramic route and their
dielectric properties were investigated in the radio and microwave
frequency regions. SrLa2Mg2W2O12 sintered at 15001C
has er525.2, Quf515 900 GHz (at 4.9 GHz), and sf50
ppm/1C. Sr2La2MgW2O12 sintered at 15251C has er524.7,
Quf535 000 GHz (at 4.7 GHz), and sf583 ppm/1C. The
dielectric properties of these ceramics are reported for the first
time.
I

Summary form only given. Telecommunications has continued to push optical fibers towards ever-more demanding applications-such as high bit rates, dense wavelength-division multiplexing (DWDM), and long distances-and in response there has been renewed interest in alternative fiber designs to lift fundamental limitations of silica fibers. A particularly exciting departure from traditional fibers are fibers based on photonic band gaps, forbidden frequency

One key failure root cause during wafer production is the electrical test by probing all interconnects of each die of the wafer. The probing process can result in excessive damage of the back end of line (BEOL) wafer layers underneath the probe pad, especially if brittle low-k dielectrics are used. The industry is trying to reduce design limitations for these under pad areas. A 3D sub-modeling simulation approach has been used to investigate stress states in layers below the probe pad. The dynamic behavior of the needle is determined by modal analysis. Its representation and calculation is done by an analytical model using the modal superposition method. These small, specialized simulation models help to distribute the simulation effort, by handling specific aspects of the real process, such as the contact problem, needle dynamics and homogenization of fine structures. The results showed that the needle dynamics can be neglected during further studies. The static load due to the max...

We foresee applications and interesting possibilities of incorporating the photonic crystals concept into superconducting electronics. In this paper, we present interesting features of the computed lower band structure of a nondissipative superconductor-dielectric superlattice using the two-fluid model and the transcendental equation [Pochi Yeh, Optical Waves in Layered Media, Wiley Series in Purl and Applied Optics (Wiley, New York, 1988)]. The necessary conditions for approximating the complex conductivity by an imaginary conductivity is derived and the feasibility of achieving the conditions are discussed. The superlattice dispersion obtained is similar to that of the phonon-polariton dispersion in ionic crystal. We found a nonlinear temperature-dependent "polariton gap" and a low-frequency (plasma) gap, and suggested the existence of a photon-superelectron hybrid around the polariton gap. The polariton gap may be observed in an infrared-microwave regime using a high-T-c, superconductor with sufficiently low normal-fluid relaxation time (approximate to 10(-15) s), and in an optical regime using lower penetration depth (approximate to 50 nm) and extremely low relaxation time (approximate to 10(-17) s).

The transversely bianisotropic uniaxial medium considered in the present article can be obtained, e.g., by mixing metal helices with an isotropic base medium in such a way that the axes of the helices are randomly oriented but perpendicular to a fixed direction in space. The medium is a generalization of the well-studied chiral medium, and is somewhat similar to the recently studied axially bianisotropic uniaxial medium, which has interesting polarization properties. Plane-wave propagation in the medium is studied and the solution for the dispersion equation is given. Numerical examples for the wave numbers corresponding to the two eigenwaves of the medium are displayed. It is seen that, unlike in the axially bianisotropic uniaxial medium, there are no optical axes in the present medium, in general. © 1993 John Wiley & Sons, Inc.

The resistance to plasma-induced damage of various nanoporous, ultra low-porous SiCOH films used as interconnect dielectric materials in integrated circuits was studied. These films are susceptible to damage by plasma processes used during nanofabrication. The dielectric constants and chemical compositions of four dielectric films were correlated with measured amounts of plasma damage. Films deposited with higher carbon content in the form of Si– CH 3 and SiCH 3 2 bonding exhibited less plasma damage than similar films with lower carbon content.

A cerium-doped SrTiO3 compound with the composition Sr0.4Ce0.4TiO3 has been produced by
conventional solid-state processing. The structure of this compound was analyzed by X-ray, electron,
and neutron diffraction. While no superlattice can be observed via X-ray diffraction, both electron
and neutron diffraction show evidence of a noncubic supercell caused by antiphase tilting of oxygen
octahedra. The most likely space group is C2/c, corresponding to an a-b-b- tilt system. Octahedra
are tilted by ∼5 about the pseudo-cubic a-axis and ∼1.5 about the pseudo-cubic b- and c-axes.
Introduction
It has previously been experimentally verified1 that
charge compensation in cerium-doped SrTiO3 compositions
occurs via A-site vacancy formation, with Ce3þ
dopant cations occupying Sr2þ
sites and creating A-site
vacancies via the reaction
Ce2O3 sf SrTiO3 2Ce••
Sr
þ V
00
Sr
þ 3O

O
These materials typically have dielectric constants in the
113-185 range and quality factors in the range of
6000-11000. As such, they are promising, relatively
inexpensive, lead-free candidates for high-permittivity
applications (e.g., cellular handsets) in the wireless telecommunications
field.
Bamberger et al.2 first reported the existence of the
compound Sr2Ce2Ti5O16 and a series of solid solutions of
the type Sr2þnCe2Ti5þnO16þ3n (n e 7) in 1994; however, the
crystal structure and phase purity of these compounds were
not well-established. Sreemoolanadhan et al.3 subsequently
reported the microwave dielectric properties of ceramics in
this system. Subodh et al.1 established via X-ray photoelectron
spectroscopy (XPS) that the oxidation state of theCe in
such ceramics is chiefly Ce3þ
rather than Ce4þ
, so the
formula is more correctly written as Sr2þnCe2Ti5þnO15þ3n
or, more simply, Sr1-3x/2CexTiO3, where x=2/(n þ 5).
The structure of Sr1-3x/2CexTiO3 (0.1333 e x e 0.4) was
initially reported as cubic, Pm3m, based on X-ray diffraction
(XRD) data1 and vibrational spectroscopy work.

• Straightforward synthesis for 0-3 Sr 0.5 Ba 0.5 Nb 2 O 6-CoFe 2 O 4 composites. • Monitoring the phase evolution during sintering to ceramics bodies. • Determination of Curie temperature. • Impedance spectroscopy up to 200 • C and 10 MHz. • Investigations of the magnetoelectric coefficient in dependence on magnetic DC field, frequency, and temperature.

This paper reports on the synthesis of polycrystalline (Li,Ti)-doped NiO powders (i.e., LixTi0.1Ni1−xO, abbreviated as LTNO) by the solid-state synthesis method. Note that, the doping concentration of Ti is kept constant (x∼0.10) in the stoichiometry, the difference in the material behavior of LTNO samples can only be attributed to the effect of Li. X-ray diffraction patterns confirmed a cubic rock-salt structured NiO-based phase with the presence of minor NiTiO3 phase, were reported elsewhere [Venkata et al., Chem. Phys. Lett., 649 (2016) 115–118.]. Dense microstructures were obtained using ultra high resolution scanning electron microscope. A high dielectric constant (ε∼104) near room temperature at low-frequency was observed in LTNO ceramics. Weak temperature dependence of dielectric constant over the measured compositions (x = 0 to 0.10) was observed in the LTNO ceramics. A giant dielectric constant of 104–105 at high temperatures (120–170 °C) for certain LTNO compositions (x = 0.15 to 0.3) was observed in the sintered ceramics. The origin of the high dielectric constant observed in these LTNO ceramics is attributed to the Maxwell–Wagner polarization mechanism and a thermally activated mechanism.

В данной книге изложены основные особенности диэлектрических резонаторов и принципы их применения для ЭПР спектроскопии, обобщен опыт авторов по моделированию и исследованию свойств резонаторов из монокристаллического танталата калия и керамики с высокой диэлектрической проницаемостью. Рассмотрены материалы, перспективные для применения в качестве ЭПР резонаторов, сделан прогноз относительно направлений дальнейшего развития в этой области. Книга предназначена студентам и преподавателям физических и радиофизических факультетов ВУЗов, материаловедам и специалистам в области техники СВЧ.

: In this work, the differences in the behavior and properties of the emitted electron beam from tungsten (W) tips were studied before and after coating these tips with a thin layer of dielectric material followed by a thin layer of gold, to improve the emission current density, stability and emission current pattern concentration. The core of the composite cathode is made of high-purity tungsten (W). Measurements have been made with clean W emitters before and after coating these tips with two types of epoxy resins (epoxy 478 resins or epoxy UPR- 4 resins) followed by a thin layer of gold. For critical comparison, several tungsten tips with various apex-radii have been prepared using electrochemical etching techniques. The emitters have been coated by dielectric thin films of various thicknesses and the layer of Au used for coating the Epoxy layer has the same thicknesses. Their behavior has been recorded before and after the process of coating. These measurements include the current-voltage (I-V) characteristics and Fowler-Nordheim (F-N) plots. Imaging has also been done using a visible light microscope (VLM), along with a scanning electron microscope (SEM) to help in characterizing the epoxy layer thickness on the tip surface after coating. Besides, the emission patterns have been recorded from the phosphorescent screen of a field electron emission microscope (FEM). Having two types of composite systems tested under similar conditions provided several advantages. These measurements helped in producing a new type of emitters that have more suitable features with each of the two resins. Keywords: Cold field emission, Nano emitter, Dielectric coating, Au layer.

An important obstacle in the life expectancy of high voltage equipment is the progressive and systematic damage to insulation systems caused by Partial Discharge (PD). The evolution of PD activity is symptomatic of the insulation state. The characterization of these PD patterns may provide additional information into the nature and extent of various defects. By looking at a new generation of recently developed piezoelectric sensors with notable features (economic, large broadband frequency response, flexible, miniature, etc.), this study will investigate the applicability of this technology as an efficient partial discharge detector. We will provide experimental validation through a comparative study using conventional system measurements which are widely recognized within the industry.

In this study, we have demonstrated a comparison of the dielectric and electric properties achieved in P(VDF-TrFE)/ PZT and P(VDF-TrFE) doped with multi-walled carbon nanotubes (MWCNT). PZT/P(VDF-TrFE) composites (0–3 type) doped with MWCNT were prepared and fabricated by the conventional cost effective solution casting technique. The dielectric and electric transport properties of composite films have been investigated. The dielectric parameters of the composite films were calculated by the measurement of capacitance and dielectric loss. The dielectric constants, ε' and ε'', each a function of temperature and frequency have been determined. The results showed an increase in both quantities with increasing frequency and temperature. From the Cole-Cole plot, the optical dielectric constant, static dielectric constant, spreading factor α, and the molecular relaxation time were calculated.

The Ca(B=
1/2Nb1/2)O3 [B' =La, Pr, Nd, Sm, Eu, Gd, Tb, Dy,
Ho, Y, Er, Yb, and In] complex perovskites have been prepared
by conventional solid-state ceramic route. The structure and
microstructure of the ceramics have been characterized by X-ray
diffraction and scanning electron microscopy methods. The
ceramics have dielectric constant (er) in the range 23–32,
normalized Q-factor (Qu
f) 11 000–38 000 GHz and temperature
coefficient of resonant frequency (sf) 43–5.2 ppm/1C. The
microwave dielectric properties of Ca(B0
1/2Nb1/2)O3 ceramics
are found to depend on the ionic radii of B0-site elements and
tolerance factor (t). The substitution of Ba21 and Sr21 for Ca21
resulted a phase transition in Ca(B0
1/2Nb1/2)O3 ceramics. The
(Ca0.05Ba0.95) (Y1/2Nb1/2)O3 has sf close to zero (1.2 ppm/1C)
with er535 and Qu
f548 500 GHz and is proposed as a
useful material for base station applications. Dielectric properties
of the Ca(B0
1/2Nb1/2)O3 ceramics were tailored by the
addition of TiO2 and CaTiO3

AWO4 (where A = Zn 2+ , Mg 2+ , Ni 2+ and Co 2+) tungstate ceramics were synthesised from a standard ceramic route, and their sintering behaviour and microwave dielectric properties were investigated. All AWO4 powders formed single-phase materials, except MgWO4 , and they all had a wolframite-like monoclinic P2/c (13) structure, not the tetragonal scheelite structure found in CaWO4. MgWO4 had a poor Qf which deteriorated with further sintering, due to discontinuous grain growth at relatively low temperatures of 1000 • C and over. At higher temperatures, ZnWO4 , NiWO4 and CoWO4 have high Qf values at 1200 • C of 62,800, 24,900 and 38,600 GHz, respectively, which will all almost certainly be improved with firing at higher temperatures, particularly in the case of CoWO4. Although not at all well sintered, ZnWO4 and CoWO4 have high Qf values of 34,000 and 28,900 GHz, respectively, at temperatures below the LTCC limit.

Research on alternative dielectric gases to eliminate the disadvantages of SF6, which is widely used in GIS and switching systems in the power system engineering, has been an important study topic in the literature for nearly 40 years. Because of environmental priorities defined by international agreements such as the Kyoto Protocol and Doha Amendment, the restrictions on the use of SF6 make these studies an obligation. Although the number of alternative dielectric gases studied for this purpose is quite high, these gases can be classified under the titles of non-synthetics, hydrocarbons (HCs), fluorocarbons (FCs), hydrofluorocarbons (HFCs), fluoronitriles (FNs), fluoroketones (FKs) and other synthetic gases. In this study, the gases classified under these titles are compared using the dielectric constant relative to SF6, Global Warming Potential (GWP), atmospheric lifetime, boiling point and toxicity parameters used in the comparison of dielectric gases. When compared with these pa...

Being the partial differential equations along with the Lorentz law the Maxwell's equation laid the foundation for classical electromagnetism, classical optics, and electric circuits. The equations provide a mathematical model for electric, optical, and radio technologies, such as power generation, electric motors, wireless communication, lenses, radar etc. Maxwell's equations describe how electric and magnetic fields are generated by charges, currents, and changes of the fields.[note 1] One important consequence of the equations is that they demonstrate how fluctuating electric and magnetic fields propagate at a constant speed (c) in the vacuum, the "speed of light". Known as electromagnetic radiation, these waves may occur at various wavelengths to produce a spectrum from radio waves to γ-rays. The equations are named after the physicist and mathematician James Clerk Maxwell, who between 1861 and 1862 published an early form of the equations that included the Lorentz force law. He also first used the equations to propose that light is an electromagnetic phenomenon.

The Earth’s core, mantle and crust are composed of rocks and minerals, and exhibit electrical and magnetic phenomena. Electrical data in particular are extremely sparse for Earth materials; fewer than one hundred minerals have piezoelectric data associated with them, for example. This type of data helps to constrain Earth processes and structures, such as core and mantle composition, geomagnetic anomalies, seismic electric signals, and others. In this review, two hundred seventeen minerals exhibiting ferroelectricity, pyroelectricity or piezoelectricity are presented, with quantitative data where known. Fifty-three of these are centrosymmetric, and explanations are given for their apparent violations of crystal theory. Some thermoelectric and magnetic data are also presented for minerals, and an overview of rock electricity is included. Recommendations for further study are given, as well, such as determining the dielectric behavior of rocks and minerals at depth, and testing minerals for alternative energy applications.

The ongoing and primary goal of the research is the pursuit of understanding of nonlinear processes in natural phenomena arising in optics and fluids. A considerable share of our attention is devoted to nonlinear optics, a relatively young subject, extremely rich in scientific and technological potential. While the studies focus on scientific questions connected with laser diode arrays, beam instabilities and the behavior of light beams at interfaces between nonlinear dielectrics, the technological ramifications and future opportunities are in many cases obvious. Optics also serves as a useful paradigm for gaining an increased understanding in other fields. For example, turbulence in optics, the study of the complex space-time filaments, patterns and defects which appear in feedback cavities and counterpropagating beams may be more analytically tractable than in other branches of continuous mechanics. There is little doubt that nonlinear optics is a subject in which interest is increasing.

This paper describes the performance of an alternative capacitive pressure gauge using lead iron tungstate as a capacitive
element over a pressure range of 418 MPa. A commercial strain gauge pressure transducer is used to get the consistency in the
calibration equation of the pressure transducer using the piston gauge pressure standard when compared with the calibration
equation of the pressure transducer obtained using the capacitive pressure gauge. A close agreement better than 1103 (over
all accuracy of the pressure transducer is 95103) demonstrate for the first time the use of the capacitive pressure gauge as
a reliable pressure standard where the required accuracy in the pressure measured is below 1103. © 1999 Elsevier Science S.A.
All rights reserved.

Composite technology, where a novel artificial material is fabricated by combining, for example, ceramic and polymer
materials in an ordered manner or just by mixing, was earlier used widely for sonar, medical diagnostics, and NDT purposes.
However, in recent decades, large numbers of ceramic–polymer composites have been introduced for telecommunication and
microelectronic applications. For these purposes, composites of 0–3 connectivity (a three-dimensionally connected polymer
phase is loaded with isolated ceramic particles) are the most attractive from the application point of view. Composites of 0–3
connectivity enable flexible forms and very different shapes with very inexpensive fabrication methods including simply mixing
and molding. In this brief review, we gather together the research carried out within 0–3 ceramic–polymer composites for
microwave substrates, also including embedded capacitor, inductor, or microwave-absorbing performances