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Gd3+ was chosen as a substitute for Bi3+ in BiNbO4 ceramics, and the substitution effects on the sintering performance and microwave dielectric properties were studied in this paper. The high temperature triclinic phase was observed only in the Bi0.98Gd0.02NbO4 ceramics when sintered at 920 °C. Both bulk densities and dielectric constant (εr) increased with the sintering temperature, while decreased with the Gd content. The quality factor ( Q) exhibited a correlation to the Gd content and the microstructures of Bi1− x Gd x NbO4 ceramics. At the sintering temperature of 900 °C, Bi0.992Gd0.008NbO4 ceramics exhibited microwave dielectric properties of εr ∼ 43.87, Q × f ∼ 16,852 GHz (at 4.3 GHz), and its temperature coefficient of resonant frequency (τf) was found to be near-to-zero. [ABSTRACT FROM AUTHOR]

This paper introduces the Dual Electro/Piezo Property (DEPP) gradient technique via Micro-Fabrication through Co-eXtrusion (MFCX) which pairs a high displacement lead zirconate titanate (PZT) piezoceramic with a high permittivity barium titanate (BT) dielectric. By grading with this material combination spatially across an actuator, the electric field is concentrated in the more active region for improved efficiency, higher displacements, and complex motions. To aid in synthesis and analysis of any gradient profile, compositional maps are provided for key material properties (density, stiffness, permittivity, and piezoelectric coefficients). The DEPP technique was validated, independent of the MFCX process, by powder pressing a conventional bimodal gradient beam which demonstrated through experiments high displacement capabilities at lower driving potentials than comparable functionally graded piezoceramic actuators. For more complex gradients, the MFCX process was adapted to the DEPP gradient technique and illustrated by the fabrication of a linearly graded prototype whose monolithic nature and gradual material variation significantly reduces internal stresses, improves reliability, and extends service lifetime. [ABSTRACT FROM AUTHOR]

Zirconium titanates are widely used in electrical (common microwave dielectrics) and optical devices as well as in bifunctional catalysis and structural ceramics. In this paper, ultrafine amorphous solid microsphere precursor particles of zirconium titanate (ZrxTi1 - xO2) with possibly tailored intraparticle nanostructure (i.e., nanosized pores) were synthesized by a “dielectric-tuning” solution coprecipitation method, in which inorganic salts were dissolved in a simple water-alcohol mixture and homogeneous nucleation and growth of particles were then induced by heating at temperatures below 100°C. Near-monodispersed particles were obtained. Particle sizes (nanometers to a few micrometers in diameter) were controlled by adjusting the process parameters such as salt concentration, alcohol-to-water volume ratio, temperature, and heating time. Nanosphere particles were produced with a rapid microwave heating nucleation-control scheme. Transmission electron microscopic analysis of each individual microsphere indicates that uniform nanostructures (a few nanometers in pore size) as well as compositional homogeneity (in terms of the Zr/Ti ratio) have been obtained inside each amorphous microsphere. In situ high-temperature X-ray diffraction data show that no phase segregation was observed in as-preprared microspheres and the transition from amorphous to the single-crystalline ZrTiO4 phase occurred around 650°C for a composition of Zr/Ti = 1. Interestingly, thermal analysis (DTA/TGA) data indicate that the solution synthesis condition seems to affect the crystallization activation energy and onset temperature, which varies from 530 to 680°C. [ABSTRACT FROM AUTHOR]

The paper presents an overview of experimental evidence and present understanding of nonlinear dielectric, elastic and piezoelectric relationships in piezoelectric ceramics. This topic has gained an increasing recognition in recent years due to the use of such materials under extreme operating conditions, for example in electromechanical actuators and high power acoustic transducers. Linear behaviour is generally confined to relatively low levels of applied electric field and stress, under which the dielectric, elastic and piezoelectric relationships are described well by the standard piezoelectric constitutive equations. Nonlinear relationships are observed above certain ‘threshold’ values of electric field strength and mechanical stress, giving rise to field and stress-dependent dielectric (ε), elastic ( s) and piezoelectric ( d) coefficients. Eventually, strong hysteresis and saturation become evident above the coercive field/stress due to ferroelectric/ferroelastic domain switching. The thermodynamic method provides one approach to describing nonlinear behaviour in the ‘intermediate’ field region, prior to large scale domain switching, by extending the piezoelectric constitutive equations to include nonlinear terms. However, this method seems to fail in its prediction of the amplitude and phase of high frequency harmonic components in the field-induced polarisation and strain waveforms, which arise directly from the nonlinear dielectric and piezoelectric relationships. A better fit to experimental data is given by the empirical Rayleigh relations, which were first developed to describe nonlinear behaviour in soft magnetic materials. This approach also provides an indication of the origins of nonlinearity in piezoelectric ceramics, in terms of ferroelectric domain wall translation (at intermediate field/stress levels) and domain switching (at high field/stress levels). The analogy with magnetic behaviour is also reflected in the use of Preisach-type models, which have been successfully employed to describe the hysteretic path-dependent strain-field relationships in piezoelectric actuators. The relative merits and limitations of the different modelling methods are compared and possible areas of application are identified. [ABSTRACT FROM AUTHOR]

This paper deals with donor, acceptor-codoped (Ba0.4Sr.6)TiO3 ceramics with distinct varistor characteristics at room temperature, which were prepared by single-step firing in air. The materials, with the Curie point at around −90 °C, exhibited a large PTCR (positive temperature coefficient of resistivity) effect of more than seven orders of magnitude in the temperature range −90 °C (the resistivity ρ ≈ 103 Ω · cm) to room temperature (ρ > 1010 Ω · cm). An apparent dielectric constant of >20000 and tan δ < 0.05 (at 100 kHz) were observed for the present materials at room temperature, and moreover, the materials exhibited nonlinear current-voltage characteristics with the nonlinear coefficient, α, in the range 7–12 and the varistor field, Ev, in the range 0.3–1.0 kV/cm. The value of α in the present materials increased systematically with increasing ρ in their PTCR temperature range. It has been found that there exists a close correlation between α and the grain-boundary potential barrier height, eφ, obtained from the ρ-T characteristic of the materials. An almost linear relationship was also found to exist between α and log Ev for the present materials. [ABSTRACT FROM AUTHOR]

Ceramic samples of modified ferroelectric sodium-bismuth titanate (Na0.5Bi0.5)0.87 Me0.13TiO3 (Me = Pb, Sr and Pb + Sr), were prepared using conventional solid state reaction techniques. The studies of powder X-ray diffraction of the obtained compounds revealed their rhombohedral symmetry at room temperature, the increase of lattice constant and the increase of rhombohedral lattice distortion (except for the material with Sr dopand, where distortion decreases). Temperature (at room temperature to 400°C) and frequency (at 20 Hz to 1 MHz) dielectric measurements reveal that A-site cations addition of Pb and/or Sr have resulted in the increase of relative electric permittivity. However, the temperature Tm (when the electric permittivity is a maximum) increases after Pb or Sr doping and it decreases after (Pb + Sr) doping. The pyroelectric and current loop measurements have shown that all samples were ferroelectric. The results of these measurements also allowed us to determine the temperature variation of the remanent and spontanous polarizations. The polarizations are found to decrease after Pb or Sr doping and increase after (Pb + Sr) doping. The piezoelectric constants ( d33 and d31) and electromechanical coupling factors ( k33 and k31) were obtained from resonance-antiresonance measurements method. The best piezoelectric and electromechanical properties have NBT doped by Pb. This ceramic may be good candidate for device applications. The diffuse ferroelectric phase transition of the investigated materials, similarly as for pure NBT, has been revealed. The properties of these materials (especially in diffuse phase transition range) can be explained by the behaviour of polar regions. [ABSTRACT FROM AUTHOR]

The (1 − x)CaSmAlO4–xSr2TiO4 (0.01 ≤ x ≤ 0.06) microwave dielectric ceramics were for the first time prepared by a conventional solid-state method. The phase composition, sintering behavior, microstructure and microwave dielectric properties were investigated as function of sintering temperature and composition. A single-phase solid solution with K2NiF4-type tetragonal structure was formed in the range of 0.02 ≤ x ≤ 0.06. All samples are well densified with very little pores. The addition Sr2TiO4 greatly improves dielectric properties originally by restraining the secondary phase and then deteriorates Q × f value because of decreasing tolerance factor. Moreover, the τf value dominated by the thermal expansion coefficient increases lineally as x rises. Finally, excellent microwave dielectric properties of εr ~ 18.1, Q × f ~ 140,433 GHz (8.5 GHz), and a near-zero τf ~ + 0.05 ppm/°C can be obtained in the x = 0.05 ceramic sintered at 1425 °C. [ABSTRACT FROM AUTHOR]

Phase constitution, microstructure, dielectric performance, polarization, breakdown strength as well as energy storage behaviors for the (1 − x)(0.45SrTiO3-0.2Na0.5Bi0.5TiO3-0.35BaTiO3)-xSnO2 (STNBTBT-Snx) were systematically investigated. The dielectric measurements exhibit a relaxor behavior, and the dielectric loss is very low (< 0.6%) at room temperature for all compositions. Significant refinement of grain size and low dielectric loss were observed with the addition of Sn, accounting for effectively enhanced dielectric breakdown strength (17.0-25.2 kV/mm when x = 0~0.09), beneficial for the energy storage applications. The sample with x = 0.07 exhibits the highest energy storage density of 2.25 J/cm3 and an energy storage efficiency of 79.51% at 24 kV/mm. Particularly, its energy storage properties were found to depend weakly on frequency (1-100 Hz). Our results suggest that this system can be a potential lead-free candidate for high electric energy storage and discharge efficiency. [ABSTRACT FROM AUTHOR]

Composites of pyroelectric ceramics and polymers are very important as their unique features and properties can be easily tailored for various specific applications. Lithium tantalatum oxide (LiTaO3, LT), the pyroelectric ceramic powder has been incorporated into a polyvinylidene fluoride–trifluoroethylene [P(VDF–TrFE) 70/30 mol%] copolymer matrix to form 0–3 composites. The composite films were prepared using ‘solvent casting’ (SC) method to disperse the ceramic powder homogeneously in the P(VDF–TrFE) copolymer matrix with various wt% of LT powder. In order to derive high pyroelectric performance, the samples were poled. Electric properties, such as the dielectric constant, dielectric loss, and pyroelectric coefficient, have been measured as a function of temperature and frequency. In addition, material figures-of-merit, very important factors for assessing many sensor applications have also been calculated. The results show that the fabricated lead free lithium tantalite: P(VDF–TrFE) composite materials have a good potential for pyroelectric infrared sensor applications. [ABSTRACT FROM AUTHOR]

In this work, the effects of Nb2O5 addition on the dielectric properties and phase formation of BaTiO3 were investigated. A core–shell structure was formed for Nb-doped BaTiO3 resulted from a low diffusivity of Nb5+ ions into BaTiO3 when grain growth was inhibited. In the case of 0.3–4.8 mol% Nb2O5 additions, two dielectric constant peaks were observed. The Curie dielectric peak was determined by the ferroelectric-paraelectric transition of grain core, whereas the secondary broad peak at lower temperature was due to strong chemical inhomogeneity in Nb-doped BaTiO3 ceramics. The dielectric constant peak at Curie temperature was markedly depressed with the addition of Nb2O5. On the other hand, the secondary dielectric constant peak was enhanced when sintered above 1280 °C for higher Nb2O5 concentrations (≥1.2 mol%). The Curie temperature was shifted to higher temperatures, whereas the transition temperature corresponding to the secondary peak moved to lower temperatures as increasing the amount of Nb2O5 more than 1.2 mol%. The decrease of this lower transition temperature was assumed to be closely related with the secondary phase formation when Nb concentration greater than 1.2 mol%. From XRD analyses, a large amount of secondary phases was observed when Nb2O5 amount exceeded 1.2 mol%. The coefficients of thermal expansion of Nb-doped BaTiO3 were increased with increasing Nb2O5 contents, resulting in large internal stress between cores and shells. Therefore, the shift of Curie temperature to higher temperatures was attributed to internal stress resulting from the formation of a core–shell structure and a large amount of secondary phase grains. [ABSTRACT FROM AUTHOR]

The microwave dielectric properties and the microstructures of Sm(Co1/2Ti1/2)O3 ceramics with B2O3 additions (0.25 and 0.5 wt%) prepared by conventional solid-state route have been investigated. The prepared Sm(Co1/2Ti1/2)O3 exhibited a mixture of Co and Ti showing 1:1 order in the B-site. Doping with B2O3 (up to 0.5 wt%) can effectively promote the densification of Sm(Co1/2Ti1/2)O3 ceramics with low sintering temperature. It is found that Sm(Co1/2Ti1/2)O3 ceramics can be sintered at 1,260 °C due to the grain boundary phase effect of B2O3 addition. At 1,290 °C, Sm(Co1/2Ti1/2)O3 ceramics with 0.5 wt% B2O3 addition possess a dielectric constant ( ε r) of 27.7, a Q × f value of 33,600 (at 9 GHz) and a temperature coefficient of resonant frequency (τf) of −11.4 ppm/ °C. The B2O3-doped Sm(Co1/2Ti1/2)O3 ceramics can find applications in microwave devices requiring low sintering temperature. [ABSTRACT FROM AUTHOR]

The crystal structure and dielectric properties as a function of temperature for Ba-based with Bi-layered structure BaBi2Nb2O9 (BBN) ceramics were investigated. The obtained results confirmed the relaxor ferroelectric behavior of the studied ceramics, including a strong frequency dispersion of the permittivity maximum and a visible shift of its temperature with frequency. Analysis of the real and imaginary part of permittivity allowed us to determine the values of Burn’s temperature and of the freezing temperature characterizing the relaxor ferroelectrics. The physical processes, responsible for the relaxor behavior of the studied ceramics are discussed. The additional low frequency dielectric dispersion at high temperatures in the paraelectric phase range was also observed. Correlation between this dispersion and the thermally stimulated depolarization current was ascertained. [ABSTRACT FROM AUTHOR]

Dielectric properties of glass ceramic samples prepared in the system [(Pb1- x Sr x )O.TiO2)]- [2SiO2.B2O3]-[K2O]-[BaO] have been studied. Dielectric constant vs temperature plots of lead rich glass ceramics samples show a peak similar to Curie peak in case of ceramic lead strontium titanate. The Curie temperature of tetragonal crystalline phase of various glass ceramics has been found to decrease with Pb/Sr ratio in the initial glass. This complements X-ray diffraction (XRD) studies carried out previously to establish that the crystallites in various glass ceramic samples are (Pb1− x Sr x )TiO3 solid solutions. [ABSTRACT FROM AUTHOR]

Several sintering aids were tested to lower the CaZrO3 ceramic sintering temperature. Numerous additions are shown to lower the densification temperature and to promote the dielectric properties with a QF product, an insulating resistivity and a permittivity enhancement, and a lowering of the temperature coefficient τℇ. A combination of dopants was tested and optimised, resulting in a low temperature sintering ceramic based on CaZrO3, LiNO3, SiO2 and TiO2. The samples sintered at 1000°C in oxidising or reducing atmosphere exhibit very attractive properties, with a QF product of nearly 15, ℇ ∼ 28, a near zero τℇ and ρi ∼ 1012 Ω · cm. The sintering mechanisms of this ceramic are also debated. [ABSTRACT FROM AUTHOR]

SrBi2(Nb1 - xVx)2O9 (0 ≤ x ≤ 0.3 in molar ratio) ceramics have been fabricated via conventional sintering at elevated temperatures. Interestingly sintering the pellets in the 1320–1470 K temperature range yielded partially grain oriented ceramics. The orientation factor (f) monitored via X-ray powder diffraction studies was found to increase with increasing V2O5 content and reached 83% for x = 0.3. The increment in (f) was not that significant with increase in sintering temperature and its duration. The microstructural studies suggest that V2O5 has a truncating effect on the abnormal platy growth of SBN grains. The dielectric constant (ℇr) and loss (D) measurements as functions of both temperature and V2O5 content have been carried out along the directions parallel (ℇrp) and perpendicular (ℇrn) to the cold pressing axis of the pellet. The anisotropy (ℇrn/ℇrp) associated with ℇr was found to be 1.11 at 300 K and 2.1 at the Curie temperature, (Tc) respectively. Different dielectric mixture formulae that were employed to analyze the effective dielectric constants of these samples with varying porosity confirmed that the experimental value of ℇr was comparable with that obtained using Wiener's formula. Impedance spectroscopy was employed to rationalize the electrical behavior of these ceramics. The pyroelectric coefficients along the directions parallel and perpendicular to the pressing axis of the grain oriented (83%) SBN ceramic at 300 K were 0.13145 mC/m2K and 0.26291 mC/m2K respectively. The ferroelectric properties of these grain-oriented ceramics were better in the direction perpendicular to the pressing axis than those in the parallel direction. [ABSTRACT FROM AUTHOR]

The microwave dielectric properties and the microstructures of LaAlO3 ceramics with B2O3 additions (0.25–1 wt%) prepared with conventional solid-state route have been investigated. Doping with B2O3 (up to 0.5 wt%) can effectively promote the densification of LaAlO3 ceramics. It is found that LaAlO3 ceramics can be sintered at 1400°C due to the liquid phase effect of B2O3 addition. The Q × f value as well as the dielectric constant decreases at higher B2O3 doping level (1 wt%) due to the increase of boundary phases. At 1460°C, LaAlO3 ceramics with 0.5 wt% B2O3 addition possesses a dielectric constant (ℇr) of 22.9, a Q × f value of 44700 (at 9 GHz) and a temperature coefficients of resonant frequency (τf) of -36 ppm/°C. The B2O3-doped LaAlO3 ceramics can find applications in microwave devices requiring low sintering temperature. [ABSTRACT FROM AUTHOR]

Pb(Zn1/3Ta2/3)O3-PbTiO3 ceramic compositions were modified by the introduction of Nb to the octahedral lattice sites. Resultant tendencies in the perovskite formation and dielectric properties were examined. System powders were prepared using a B-site precursor method. Developed structures and lattice parameters of the system compositions were investigated by powder X-ray diffractometry, from which the parameter of a hypothetical perovskite Pb(Zn1/3Ta2/3)O3 is proposed. Weak-field low-frequency dielectric responses of the system ceramics were measured. [ABSTRACT FROM AUTHOR]

TiO2 ceramics doped with 1.0 mol% Ca and different concentrations of Ta were obtained by sintering processing at 1450°C. The microstructures, nonlinear electrical behavior and dielectric properties of the ceramics were investigated. The samples have nonlinear coefficients of α = 2.0–5.0 and ultrahigh relative dielectric constants which is up to 105. Especially, the effects of Ta dopant on the nonlinear electrical characteristics and dielectric properties of the (Ca, Ta)-doped TiO2 ceramics were studied in detail. When the concentration of Ta is 2.0 mol%, the sample exhibits the highest nonlinear coefficient and a comparatively lower dielectric constant. By analogy to a grain-boundary atomic defect model, the effects of Ta and the nonlinear electrical behavior of the TiO2 system were explained. [ABSTRACT FROM AUTHOR]

Crystalline structure, microstructure and dielectric properties for Ba(Ti1-yCey)O3 (0 ≤ y ≤ 0.5) ceramics have been studied. Dense ceramics with the relative density higher than 95% and grain size of 0.7-1.5 µm have been obtained. The limit of the solid solubility is determined as y = ∼0.3 by the X-ray diffraction, SEM, and dielectric properties measurements. The crystalline symmetry is tetragonal for the sample with y = 0.02 and cubic for y ≥ 0.06 at room temperature, and the unit cell increases with increasing Ce content in the solid solution range. Correspondingly, the dielectric response exhibits three dielectric peaks for y = 0.02, and one pinched dielectric peak with ferroelectric relaxor behavior for y ≥ 0.06. [ABSTRACT FROM AUTHOR]

The crystalline structure, microstructure and dielectric properties of the (Sr1-1.5xBix)TiO3 (0 ≤ x ≤ 0.267) ceramics were studied. Cubic solid solutions were determined for x ≤ 0.2 at room temperature. However, lattice distortion was detected by Raman spectra. A dense microstructure with the grain sizes of 2-4 µm was obtained for (Sr1-1.5xBix)TiO3 (0 ≤ x ≤ 0.2) ceramics. The Bi concentration was examined and found to be in agreement with the nominal composition and overall uniformly distributed in the sample. Different from the observations in the earlier literature for other doped quantum paraelectrics, where only an induced dielectric anomaly was reported, there are three Bi induced dielectric modes A, B, and C in the Bi doped SrTiO3 samples. The occurrence of the "impurity modes" and the "ferroelectric relaxor mode" and their evolution are demonstrated as a function of Bi concentration. [ABSTRACT FROM AUTHOR]

The effects of silver doping on PMN-PZN-PT relaxor ferroelectric ceramics were investigated in order to demonstrate the roles of the inner electrodes in the cofiring of MLCCs, because silver could diffuse from an electrode layer into a dielectric layer. Even if the addition of silver promoted the sintering of ceramics, the insulation resistance and the dielectric properties were changed to a certain extent so that they had a great influence on the reliability of MLCCs. Defect chemistry principles were used to analyze the mechanism of action of silver doping. The relationship of silver migration and microstructural formation was also discussed [ABSTRACT FROM AUTHOR]

The pyroelectric and dielectric bolometer properties of Sr modified BaTiO3 ceramics were investigated for thermal IR detector applications. The (Ba1−x, Srx)TiO3 solid solution ceramics have been prepared by adding 10–40 at % SrTiO3 to BaTiO3 and with different sintering conditions and under dc fields. The relationships of processing parameters, microstructures, dielectric/pyroelectric properties and dc fields are discussed. And the “figures of merit” are compared between pyroelectric-type and dielectric bolometer-type IR sensors based on the experimental results. [ABSTRACT FROM AUTHOR]

Ferroelectric and dielectric properties of barium titanate (BaTiO3) bulk ceramics and thin films have been investigated. The bulk ceramics and thin film samples have been prepared from barium acetate [Ba(CH3COO)2] and titanium(IV)isopropoxide [Ti(CH3)2CHO)4] precursors by sol-gel technique. The as-grown bulk powder and thin films were found to be amorphous, which crystallized to tetragonal phase after annealing at 700°C in air for one hour. The values of the spontaneous polarization (Ps), remanant polarization (Pr) and coercive field (Ec) of the bulk ceramics were found to be 19.0, 12.6 μC cm−2 and 30 kV cm−1 respectively. In the case of the film, the values of Ps, Pr and Ec were respectively found to be 14.0, 3.2 μC cm−2 and 53 kV cm−1. The capacitance-voltage (C-V) characteristics of the film also showed polarization hysteresis. The values of the dielectric constant (ε) of the bulk ceramic and thin film at 1 kHz were found to be 1235 and 370 respectively. Both the films and ceramics showed dielectric anomaly peaks at 125°C, showing ferroelectric to paraelectric phase transition. [ABSTRACT FROM AUTHOR]

The single-phase BaNd2Ti4O12 powder was successfully prepared at 1000 to 1200°C by the KCI molten salt method, and the sinterability of the powder was briefly studied. Longitudinal single-phase powders could be fully densified at 1450°C. Measurements showed that the dielectric constant and Q-value of the densified ceramics were high, and the Q-value in particular was markedly affected by the preparatory conditions. These results indicate that single-phase BaNd2Ti4O12 powder can easily be prepared by the KCI molten salt method and that the ceramics made from the powder show optimal properties for microwave dielectrics. [ABSTRACT FROM AUTHOR]

The dielectrical properties of glass ceramics derived from SrO–B2O3–Al2O3–TiO2 glasses are improved by doping the starting material with Nb2O5 and judicious choice of heat treatment conditions. In order to understand this effect the local environment of the niobium ions is studied by EXAFS (extended X-ray absorption fine structure) investigations at the Nb-K edge. For comparison purposes Ti-K and Sr-K EXAFS spectra have also been measured. The experiments suggest that the niobium ions are incorporated onto titanium sites in the crystalline SrTiO3 phase formed during the thermal treatment. [ABSTRACT FROM AUTHOR]

The article discusses the preparation, characterization and dielectric properties of ceramics. Materials of tungsten-bronze structure belong to an important family of dielectric materials, which display interesting ferroelectric, pyroelectric, piezo-electric, and nonlinear optic properties for applications in various electric devices. Dielectric constant increases with decreasing frequency due to the presence of all different types of polarization at low frequency. The comparatively low room temperature dielectric constant observed in the ceramic sample indicates that it may have attractive benefits in electrxptic and infrared pyroelectric detector applications when grown in buck single crystal or thin-film form.

The article focuses on the preparation, structural and dielectric properties of ceramics. Electronic materials of high dielectric constant, low loss, and good stability of temperature coefficient of resonant frequency have been extensively studied because of their applications in discrete and multilayer (MLC) capacitors, microwave telecommunication applications, and low loss substrates for microwave integrated circuits. The densities of the compacts were measured by the Archimedes method. The temperature coefficient of the dielectric constant was calculated using the data in the temperature range of 20 to 85 degrees centigrade at 1 MHz.

A complex perovskite oxide Ba2HoNbO6 has been developed as a non-reacting substrate for YBa2Cu3O7-δ superconducting film with lattice constant a = 8.3905 Å. The dielectric constant (30) and loss factor value (5 × 10-3) of the material are in the range suitable for its use as substrate for microwave applications. A YBa2Cu3O7-δ superconducting thick film dip coated on Ba2HoNbO6 substrate gave a Tc(0) of 92 K and current density of ∼1.2 × 104 A cm-2. [ABSTRACT FROM AUTHOR]