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In this paper, an unexplored solid solution (1-x)Bi(Cu1/2Ti1/2)O3-(x)PbTiO3 has been synthesized and characterized for its crystal structure, dielectric and ferroelectric properties aimed at a selected composition, i.e., 0.30 Bi(Cu1/2Ti1/2)O3-0.70PbTiO3. The paper unveils the different synthesis approaches to achieve pure-phase in Pb-based perovskite-structured materials that are prone to produce impurities during synthesis. The Rietveld refinement of the XRD pattern confirms a tetragonal crystal structure (P4mm) of the composition. The ferroelectric properties of the as-prepared composition are also discussed using P-E hysteresis and PUND characteristics. The composition shows a high Tc (480 °C) and low dielectric losses, making it suitable for high-temperature applications. [ABSTRACT FROM AUTHOR]

Lead-free K0.47Na0.47Li0.06NbO3 added with different oxides such as ZnO, Na2SiO3, Bi2O3, NiO, and CoO were prepared with conventional two steps sintering ceramic method where the samples were sintered at 1050 °C(5 min) and 950 °C(4h). The phase structures and crystallite sizes were studied using X-ray diffraction analysis. A dispersive behavior is observed when dielectric constant and dielectric loss were studied with variation in frequency in the range from 20 Hz to 5 MHz at room temperature. It is seen that addition of oxides improved the dielectric properties. The a. c. conductivity and impedance characteristics for the samples were also measured for a wide range of frequencies using an impedance analyzer. The Nyquist impedance plot for these samples studied for the conduction mechanism. The results were analyzed and presented in the paper. [ABSTRACT FROM AUTHOR]

In this paper, an unexplored solid solution (1-x)Bi(Cu1/2Ti1/2)O3-(x)PbTiO3 has been synthesized and characterized for its crystal structure, dielectric and ferroelectric properties aimed at a selected composition, i.e., 0.30 Bi(Cu1/2Ti1/2)O3-0.70PbTiO3. The paper unveils the different synthesis approaches to achieve pure-phase in Pb-based perovskite-structured materials that are prone to produce impurities during synthesis. The Rietveld refinement of the XRD pattern confirms a tetragonal crystal structure (P4mm) of the composition. The ferroelectric properties of the as-prepared composition are also discussed using P-E hysteresis and PUND characteristics. The composition shows a high Tc (480 °C) and low dielectric losses, making it suitable for high-temperature applications. [ABSTRACT FROM AUTHOR]

Resistive random access memory is promising for next-generation nonvolatile memory, which has high memory density, low power consumption, and fast read/write speed. However, the resistive switching (RS) mechanism in oxide ferroelectric thin film devices is still unclear. In this paper, Pt/BiFeO3/La0.5Sr0.5CoO3(Pt/BFO/LSCO) heterostructures were deposited on (111)SrTiO3(STO) substrates by magnetron sputtering. X-ray diffraction confirmed the epitaxial relationship between (111)BFO//(111)LSCO//(111)STO. Atomic force microscopy (AFM) showed that (111)BFO had an island structure with uniform grain distribution. The Pt/(111)BFO/(111)LSCO heterostructures exhibit obvious ferroelectricity and RS effects. The results of C-V analysis and I-V fitting indicate that the RS is caused by the space-charge-limited conduction mechanism. [ABSTRACT FROM AUTHOR]

The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNT-BMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]

The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNTBMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]

The present paper is devoted to the study on the dielectric properties and microstructure of samples of multicomponent ceramics of the PZT system with various Curie temperatures. The coexistence of two ferroelectric phases is shown. They behave differently during the poling process. The temperature dependence of the dielectric permittivity of pooled samples of compositions near the morphotropic phase boundary exhibits anomalies below the Curie temperature. [ABSTRACT FROM AUTHOR]

In this paper, the ferroelectric (FE) properties of 20-nm-thick Hf0.5Zr0.5O2 films deposited by an atomic layer deposition technique by using O3 or H2O as an oxygen source were studied. For both oxygen source, the Hf0.5Zr0.5O2 films exhibited the formation of a non-centrosymmetric orthorhombic phase, which was responsible for the FE behavior. However, it was shown that the H2O-based Hf0.5Zr0.5O2 films were more unsuitable for hydrogen from H2O than the O3-based Hf0.5Zr0.5O2 films, which reduced the FE polarization and increased the leakage behavior. The results indicated that the use of O3 as an oxygen source in the ALD process has potential for the fabrication of FE Hf0.5Zr0.5O2 films for next generation memory applications. [ABSTRACT FROM AUTHOR]

This paper presents the application of an ordinary sintering process for 3 h in air to fabricate highly dense (Na0.52K0.44Li0.04)(Nb0.88Sb0.08Ta0.04)O3 (NKN-LST) ceramics with excellent piezoelectric properties at a lower sintering temperature through the use of excess Na2O as a sintering aid. The effects of sintering temperature in the range 940–1100 °C and Na2O addition in the range of 0 to 3.0 mol% on the density, sintering behavior, microstructure, dielectric and piezoelectric properties of the NKN-LST ceramics are investigated. Analysis reveals that NKN-LST ceramics samples sintered at 1020 °C for 3 h in air with 1.5 mol% excess Na2O achieve the highest electromechanical coupling factor and piezoelectric coefficient values of 0.45 and 364 pC/N, respectively. [ABSTRACT FROM AUTHOR]

Recent years have seen a considerable research interest in multiferroic materials for their potential application as sensors and actuators. However, the scarcity of these materials in a single phase and the weak coupling of their ferroic components have directed research toward multiferroic heterostructures. These systems operate by coupling the magnetic and electric properties of two materials, generally ferromagnetic and ferroelectric, via strain. In this paper, thin films have been grown by chemical solution deposition (CSD) using spin coating technique using rotations peed of 4500 rpm and time of 50 s and dried at 120○C for 20 min. The optical, dielectric, magnetic, ferroelectric, ferromagnetic, and piezoelectric properties of thin films have been investigated by Uv- Visible spectrophotometer (300-2500) nm, X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM) respectively. PZT/CFO thin films deposited at different temperatures from 400 °C, 500 °C and 600 °C. The as-deposited PZT/CFO show week piezoelectricity and the effective piezoelectric coefficient d33 because the materials deposited on the films not only the PZT layer but also the CFO layer, which decreases the piezoelectricity of these films. PZT/CFO Films were then recorded to enhance all physical properties (dielectric, optical, structural, surface morphology, and magnetic properties) as the sintering temperature increased. The images of a thin film before and after treatment with Nd-YAG, which have Power from 10 mw to 5300 mw, Pulse width: 7 ns pulsed laser, Repetition Rate: 10 HZ, and wavelength spectrum in (IR, Vis) laser beam indicate that sample prepared before treated has a lot of porous and agglomeration which decreases after treatment. [ABSTRACT FROM AUTHOR]

This paper presents a study of microstructure and dielectric properties of solid solutions of (1-х)BiFeO3 − x/2 PbFe1/2Nb1/2O3 − x/2 PbFe2/3W1/3O3 system with x = 0.05 ÷ 0.50 using X-ray diffraction analysis. Phase diagram of the studied system at room temperature is obtained. Critical influence of oxygen defects and liquid phase on formation of structure and microstructure of the samples is detected. Relaxor nature ε′′/ε0 for the studied solid solutions is demonstrated dealing with occurrence of Maxwell-Wagner's relaxation due to movement of oxygen vacancies. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the dielectric response in single crystals of barium strontium niobate doped with thulium of various concentrations. It is shown that the dielectric permittivity increases with increasing concentration of thulium. For as-grown samples the dispersion of the permittivity is observed in the frequency region of 106 Hz. The dependence is not observed for the samples polarized under DC field. For all the samples studied, the switched polarization increases and the coercive field decreases under action of an AC field. [ABSTRACT FROM AUTHOR]

In this paper, thick film antiferroelectric ceramics (1-x)(Pb0.97La0.02)(Zr0.46Sn0.48Ti0.06)O3-xH3BO3 ((1-x)PLZST-xH3BO3, x = 0–0.025) were prepared by solid state sintering and tape-casting method. The effects of boron-doping on the microstructure, dielectric properties and energy storage properties of (1-x)PLZST-xH3BO3 ceramics were investigated. Appropriate boron-doping can improve the stability of antiferroelectric phase, delay phase transition and increase saturation polarization strength. Compared with the undoped PLZST thick films, the maximum polarization intensity increased by 1.9 times and the residual polarization decreased by 37%. When x = 0.020, the maximum recoverable energy storage density is 2.74 J/cm3, and the energy storage efficiency is 88.12%. [ABSTRACT FROM AUTHOR]

This paper discusses the approach to formulate mathematical model (MM) for synthesis of any ceramic and to decide reliability of density measurement. In the research of basic science, the majority of operations are still executed manually which needs to be focused and develop a mathematical relation which simulate the real input and output data directly. The advantages and limitations of the developed mathematical models are identified and the models are classified in terms of range of application and goals. In this study, a generalized experimental data based model developed to simulate the contemporary techniques for the purpose of study, compression, inducing generalized approach for the mathematical model of ceramic synthesis. The findings indicate that the topic understudy is of great importance, as no such approach of experimental data based mathematical simulation is adopted for the formulation of synthesis of ceramics so far. Thus the results of this experimental research would be useful to industry for manufacturing of multilayer capacitors. [ABSTRACT FROM AUTHOR]

MnO2 added potassium sodium niobate (KNN) electroceramics were prepared by conventional double sintering ceramic route. The samples prepared have the compositional formula K0.5Na0.5NbO3+ (x)MnO2 where x = 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt% and 25 wt% is the amount of MnO2 added. The sintering of the samples was done using the microwave sintering technique. Pre-sintering was done at 850 °C for 20 min. Different sintering conditions may results in KNNs with varied properties. The studies of the structural properties of the prepared samples were done by X-ray diffraction (XRD) technique. It has been found that addition of MnO2 to KNNs and sintering at 1000 °C for 20 min and at 1050 °C for 10 min showed all the KNNs crystallization in tetragonal phase with nearly similar structural parameters. The electrical properties such as dielectric constant, dielectric loss and ac conductivity of the prepared samples were investigated using an impedance analyzer. The room temperature frequency variation of electrical properties showed a dispersive behavior for all the samples. The temperature variation of the dielectric properties showed an increase with the increase of temperature. The results of the various measurements are discussed in the paper. [ABSTRACT FROM AUTHOR]

In the present paper the phenomena predicted in [2] for substances with FE and AFE phases coexisting is experimentally shown for Pb(Mg 1/3 Nb 2/3 )O 3 and Pb(B′ 1/2 B′′ 1/2 )O 3 -type compounds. Special attention is paid to analysis of their phase diagrams. The influence of external factors on the properties of these substances is considered. It is shown that all peculiarities in the behaviour of the substances in question are described on the basis of phase transitions between FE and AFE states. [ABSTRACT FROM AUTHOR]

Bent-core liquid crystal (LC) is used to dope the (4-cyano-4′-pentylbiphenyl) liquid crystal (5CB). The polarizing microscopy results show that 5CB and LC exhibit Nematic (N) and Banana-Shaped (B1) mesophases, respectively. In this paper, we use dielectric spectroscopy to determine the dielectric properties of the 1% LC doped with 5CB liquid crystal. The dielectric parameters of these materials have been determined by different applied voltage. In this respect, dielectric properties of 5CB + 1% LC have been compared with 5CB. The dielectrical anisotropy of 5CB and 5CB + 1% LC liquid crystal composite changes from the positive dielectric anisotropy to negative with the frequency of the applied voltage. The critical frequency fc values of dielectrical anisotropy for 5CB and 5CB + 1% LC composite were found to be 688 and 534 kHz, respectively. The real (ε′) and imaginary components (ε′′) of dielectric constant have been calculated by capacitance method. It has been also determined that adding LC to 5CB decreases the voltage dependent dielectric strength and increases threshold voltages. [ABSTRACT FROM AUTHOR]

In this research paper, we report the dielectric and electric investigation of series of dielectric ceramics samples with structural formula Ba2-xRe4+2x/3Ti8O24(where Re = Sm and La and x = 0.0, 0.2, 0.4 and 0.6). The dielectric parameters (i.e. dielectric constant and loss tangent) and ac conductivity are measured with impedance analyzer. This paper is presented to compare the effect of samarium and lanthanum doping on the properties of barium titanate. The research work concludes that lanthanum doping has more favorable effect on the properties. This paper also presents impedance analysis and V-I characteristics of all the samples. This is concluded that these properties are strongly dependent on frequency, temperature and composition. The investigation reports almost constant value of dielectric constant and very low loss tangent at lower temperatures. [ABSTRACT FROM PUBLISHER]

The present paper aims to study the effect of different pore forming agent on the density, porosity, pore morphology and electrical properties of porous BZT-0.5BCT ceramics. The electrical property evaluation is focused on dielectric constant, ferroelectric properties (P-E loop) and piezoelectric constant (d33 and g33) of the porous BZT-0.5BCT ceramics. BZT-0.5BCT powder was prepared by solid-state route. The porous ceramic was prepared by mixing BZT-0.5BCT with different percentage (10, 20, 30, 40 and 50 vol%) of polyvinyl alcohol (PVA) and sucrose as pore-forming agents (PFA). As a result, density, relative permittivity, remanent polarization and piezoelectric constant decreased linearly with increase in pore former addition. The pores derived from PVA and sucrose as pore former were spherical to irregular in shape. Isolated pores are observed up to 30 vol% of PFA addition and pore interconnectivity is observed at 40 vol% of PVA and sucrose addition. The decrease in electrical properties is much higher in sucrose when compared with PVA as a pore former. [ABSTRACT FROM AUTHOR]

In this paper, in order to develop the composition ceramics for piezoelectric actuator, (1-x)(Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3 - x(Bi0.5Na0.5)0.9(Sr)0.1ZrO3 ceramics were synthesized by the conventional solid state method and their piezoelectric and dielectric properties were systematically investigated. All specimens showed a typical pure perovskite structure and no secondary phase was found according to the (Bi0.5Na0.5)0.9(Sr)0.1ZrO3 substitution. When x = 0.03, the excellent physical properties of d33 = 256pC/N εr = 1753, kp = 0.411, Qm = 58 and high Tc of 285 °C were obtained for piezoelectric actuator. [ABSTRACT FROM AUTHOR]

In this paper, we will discuss piezoelectric energy harvesters of multi-layered ceramic-pillar composite structures to be used as the energy source of small size electronic devices. 0.2(PbMg1/3Nb2/3O3)-0.8(PbZr0.475Ti0.525O3) ceramics and polydi-methylsiloxane (PDMS) were employed as piezoelectric ceramic-pillar composite, which prepared in forms of rectangular pillar structures. The piezoelectric ceramic-pillar composites were sintered separately and attached on the metallic bottom electrode with poled states. Symmetric upper electrodes were attached on the other side. Subsequently, the ceramic-pillar structures of composite material were manufactured with single-layer, double-layer and triple-layer devices. Both of multi-layer and single layer devices will be compared with several analysis methods. Piezoelectric properties will be discussed including the piezoelectric constant. Also, the output power of the multi-layer and single layer devices will be studied. [ABSTRACT FROM AUTHOR]

Dielectric properties of 2,3,6,7,10,11-hexahydroxytriphenylene tetrahydrate crystallites are examined in this paper. We observe a first order, order-disorder phase transition at a temperature of 251 K. The frequency dependence revealed four relaxation regions, where two relaxations follow the Arrhenius law with activation energy of 300 meV. Our investigation shows the experimental data below the phase transition to follow the Curie-Weiss law, however, ferroelectric ordering is not observed. [ABSTRACT FROM AUTHOR]

This paper presents dielectric properties of BT-BT and BT-BF composites obtained by solvothermal solidification. We observe lower dielectric permittivity in BT-BT composites than in conventional sintered BT ceramics. The frequency dependence showed two relaxation regions that occur due to domain wall motion and acoustic resonance. Also we observed higher dielectric permittivity for BT-BF system than in conventional BF ceramics which can be attributed to addition of BT or due to epitaxially introduced strain. Lastly, we observed glassy behaviour in BT-BF system. [ABSTRACT FROM AUTHOR]

In this paper, strontium barium niobate/strontium barium titanate [SrxBa1-xNb2O6/SrxBa1-xTiO3] composite ceramics with different Sr2+/Ba2+ ratio were fabricated using a Powder-Sol (P-S) method. The formation process of SBN/SBT was studied by TG-DTA. It is found that the tetragonal tungsten bronze (TTB) phase and perovskite phase were co-present in the composite ceramics, and the Sr2+/Ba2+ ratio has an influence on the proportion between SBN and SBT. SEM results show that samples are homogeneous and fine-grained. The dielectric properties of composite ceramics were studied by impedance analyzer, and indicates that the dielectric constant and dielectric loss could be well regulated by Sr2+/Ba2+ ratio. [ABSTRACT FROM AUTHOR]

In this paper, the (Ba,Ca)(Ti,Zr)-MLCCs with nickel electrodes by free sintering and constrained sintering as different heating rate have been investigated as different heating rate with 200°C/hr, 1500°C/hr and 3000°C/hr, respectively. The BaTiO3 was adopted as constraining layer due to the tensile stress of generation resulted from the different onset temperature. The electrical characteristics were closely related to the microstructure change including electrode overlap areas and grain size by free and constrained sintering with different heating rate. The variation of dielectric constant and insulation resistance can be explained by grain size change. The variation of dielectric loss can be explained by the curve of the temperature coefficient of capacitance. To compare with the free sintering, the capacitance value of constrained sintering of MLCCs has increased regardless of the heating rates. The high capacitance, high electrode continuity (>98%) and high insulation resistance (>1010Ω) of BCTZ-based MLCC with nickel electrode can be attained by using a rapid constrained sintering technique. [ABSTRACT FROM PUBLISHER]

Investigations presented in the present work are concerning the other member of the Aurivillius family, the BaBi2Nb2O9 (BBN). This compound, which seems to be very interesting from the potential applications point of view. The dielectric characterization of this materials and influence of sintering condition on grain structure and properties of those materials had been very widely described in our previous paper. Now we would like to present the hitherto unreported electric properties of BaBi2Nb2O9 ceramics, investigated by the impedance spectroscopy (IS). IS is nondestructive method, which allows to separate grain and grain – boundary effects due to the different frequencies of the relaxation process in grain and grain boundaries. This enables us to determine the temperature dependences of grain (Rg) and grain-boundary (Rgb) resistance and evaluate their respective activation energies (Ea). Additionally a comparison between macroscopic results obtained by Impedance Spectroscopy and miroscopic direct local LC-AFM conductivity measurements are presented. [ABSTRACT FROM PUBLISHER]

This paper investigated dielectric properties of rare earth (Y, Gd, Yb)-doped barium titanate sintered in pure nitrogen. The difference in doping behaviors of intermediate rare-earth ions (Gd, Y, Yb) and their effects on the dielectric properties of barium titanate were investigated. The intermediate rare earth elements (Gd, Y, Yb) were substituted in the A-site of the perovskite lattice. The different rare earth element had a crucial effect on dielectric properties of rare-earth-doped BaTiO3. Gd-doped barium titanate had the largest dielectric constant (about 20000) and the largest dielectric loss (about 0.6), the smallest leakage current and no tunability. Y-doped specimen had the largest leakage current. [ABSTRACT FROM AUTHOR]

Recently, barium titanate (BaTiO3), the first piezoelectric ceramic developed and highly stable material, gained importance after extraordinarily high piezoelectric properties superior to PZT, were reported in the lead-free Ba(Zr0.2Ti0.8)O3-50%(Ba0.7Ca0.3)TiO3and Ba(Sn0.12Ti0.88)O3-30%(Ba0.7Ca0.3)O3ceramics. In the present work, (Ba0.7Ca0.3)(Ti0.92-xDyxSn0.08)O3ceramics withxvarying from 0 to 2.5 mol% have been prepared using conventional solid state sintering method. Homogeneously mixed raw materials were double-calcined at 1250°C for 4 h. Sintering of the uniaxially pressed powder compacts was performed at 1300°C for 4 h in air. The detailed results of the microstructural, ferroelectric, dielectric and piezoelectric studies of the ceramics are reported in this paper. [ABSTRACT FROM PUBLISHER]

In this paper, structural and dielectric properties of multiferroic composite system (1-x) Ba0.5Sr0.5TiO3(BST) – (x) Ni0.4Co0.2Zn0.4Fe2O4(NCZF) x = 0.1, 0.2, 0.3, 0.4 molar ratios have been studied. X-ray diffraction analysis of composite samples confirmed the presence of both the phases. Density measurements result indicate that composite samples although possess lower density in comparison to both the pure phases but density of the composite samples increases with NCZF content. Dielectric constant and loss of the composite samples decreases with increase in frequency due to Maxwell-Wagner relaxation mechanism. Dielectric constant of the composite samples firstly increases with increase in NCZF content followed by a decrease. [ABSTRACT FROM AUTHOR]

Polymer-based energy storage materials are widely utilized in the fields of electrical and electronics due to their high-power density and excellent charge-discharge efficiency. In this study, polyetherimide (PEI) composite films with outstanding energy storage properties were prepared by growing an inorganic barrier layer of boron nitride (BN) on the surface of PEI films through the in situ chemical vapor deposition (PECVD) method. The effects of BN deposition time on the dielectric properties, leakage current density, and energy storage properties of the composite films were investigated. The results reveal that the BN inorganic barrier layer, prepared by the PECVD method, demonstrates excellent interfacial compatibility with the PEI polymer matrix and forms a densely deposited layer. The BN inorganic barrier layer effectively suppresses carrier injection at the electrode, reduces the current density inside the PEI composite film, and improves the breakdown strength of the composite film. The composite film exhibits optimal performance when BN is deposited for 20 min. At an electric field strength of 660 MV/m, the energy storage density of the composite film reaches 6.08 J/cm3, which is 1.53 J/cm3 higher than that of pure PEI, while maintaining a charge-discharge efficiency of 90.43%. The findings of this study provide valuable theoretical support for the design of polymer-based energy storage materials. [ABSTRACT FROM AUTHOR]

In this paper the investigation of relaxor ferroelectric PbFe0.5Nb0.5O3has been carried out using the method of X-ray diffraction, magnetic and dielectric measurements over a wide range of temperatures and frequencies. It has been shown that in single crystals there is high-temperature phase transition from the ferroelectric phase to the cubic phase at a temperature of 367 K. The anomalies detected in the dependences of magnetic susceptibility χ (T) and the magnetic moment m (T) in polycrystalline at room temperature and above were found to be correlating with the anomalies detected by structural, EPR spectroscopic and dielectric measurements. [ABSTRACT FROM AUTHOR]

Complex perovskite materials are considered as a boon in this revolutionary era of microelectronic and telecommunications. In this paper we have presented the effect of replacement of Mg2+by divalent ions (Co2+, Cu2+) in Ba(Mg0.33Nb0.67)O3. We have studied the impact of replacement of Mg2+by transition elements on structural, micro-structure, dielectric properties. It is observed that on replacing the Mg2+by Co2+and Cu2+the structural symmetry shifts from hexagonal (BMN, BCoN) to tetragonal (BCuN). Further, the morphological study reveals agglomerated grain formation for BCoN and a spikes/elongated type of structure in BCuN samples. The frequency dependence of dielectric studies shows the polar behavior of BMN. On the other hand replacing Mg by cobalt or copper (having 3d7and 3d9configuration, respectively), leads to Jahn-Teller distortions introduced in the samples. The poly-dispersive natures of the samples were inferred through fitting the curves with Cole–Cole equation. [ABSTRACT FROM AUTHOR]

One of the negative effects of ferroelectric applications, particularly for electrocaloric effect (ECE) applications, is temperature hysteresis (ΔTHyst). Temperature hysteresis is the difference between the temperatures corresponding to the maximum dielectric permittivity in heating and cooling modes. The value of ΔTHyst is commensurate with the value of the ECE temperature change. The ECE is a phenomenon in which a material shows a reversible temperature change under an applied electric field. The aim of this work is to study the possibilities of temperature hysteresis reduction by varying the ceramic sintering temperature, changing the stoichiometry of BaxSr1-xTiO3 solid solutions, and changing the rate of the heating-cooling cycle. [ABSTRACT FROM AUTHOR]

The microwave dielectric properties of La2MoO6 ceramics were investigated in preparation for their application in mobile communication. La2MoO6 ceramics were prepared by the conventional solid-state method under varied sintering conditions. The X-ray diffraction peaks of La2MoO6 ceramic did not vary significantly with sintering conditions. The average grain size of La2MoO6 ceramics increased with increasing the sintering temperature and duration. The maximum density of 5.67 g/cm3, the dielectric constant ( ε r ) of 14.1, the quality factor (Q × f) of 68,000 GHz, and the temperature coefficient of resonant frequency ( τ f ) of −56 ppm/°C had been attained when La2MoO6 ceramics that sintered at 1300 °C for 4h. [ABSTRACT FROM AUTHOR]

The performance of the 0–3 piezoelectric composite consisting of two piezoelectric materials (PZT5H and PVDF) is analyzed to improve the piezoelectric properties for sensing applications using FEA and validated with the experimental and analytical results. The experimental and predicted results are showing good matches. The average piezoelectric coefficient d33 of the piezoelectric composite and the effective elastic, dielectric and piezoelectric properties of the 0–3 passive matrix piezoelectric composite were determined from the unit cell model. It is observed from the analysis that the performance of 0–3 piezo-composite has excellent piezoelectric properties and also optimized unit cell size and polymer matrix. [ABSTRACT FROM AUTHOR]

BiFeO3 nano-ceramics were synthesized using the low-temperature molten salt synthesis route to study the influence of calcination temperature and salt ratios. The Rietveld refinement revealed the distorted perovskite structure of BFO. These granular-shaped BFO samples' grains morphology was studied using the FESEM. The FTIR revealed the presence of Metal-Oxygen bonds in the BFO ceramics. The XPS studies exhibited the respective constituent elements' oxidation states and validated the presence of oxygen ion vacancies. The frequency-dependent dielectric properties were measured at various temperatures. The electrical conductivity measurement showed a linear variation as a function of frequency which validated Jonscher's power law. [ABSTRACT FROM AUTHOR]

This study investigates the dielectric properties, including dielectric constant (ɛ′), dielectric loss (ɛ″), tangent delta (tan δ), and AC conductivity (σac), of PVA/Y2O3 polymer nanocomposites (PNCs). The dielectric behavior of the PNCs was examined as a function of frequency and temperature. The results revealed that the addition of Y2O3 nanoparticles to the PVA matrix influenced the dielectric properties of the composites. In contrast to pure PVA, the PVA/Y2O3 PNCs with a 15 wt% Y2O3 loading exhibited high values of ɛ′, ɛ″, tan δ and σac are 647.49, 1607.48, 9.70 and 1.024 × 10−5, respectively, at low frequency and at particular temperature. Furthermore, the electrical properties of PVA/Y2O3 PNCs were also investigated using the Cole-Cole plots. These plots provide valuable insights into the complex impedance behavior and allow for comprehensive understanding of the electrical response of the nanocomposites. [ABSTRACT FROM AUTHOR]

The present work centered attention on novel ionic liquid (IL) based on dicationic benzimidazolium ion containing amide group (DBimIL) synthesized using dialkylation of N-ethyl benzimidazole to followed with anion exchange reaction. To explore the potential application of ILs, there is a great need to grasp their structural and physical properties. We have developed three different set of DBimIL based ionic liquids with chloride, hexafluorophosphate and perchlorate anions in aqueous media, respectively. Their structural features were studied using 1H, 13C-NMR, FTIR, and HRMS spectroscopy, respectively. The temperature-dependent dielectric characteristics of ILs were closely examined angular frequency in the range of 0.6–125 rad/s from 30 to 150 °C. The relationship between the structural and dielectric properties of ILs established. The dielectric parameters like dielectric constant, dissipation factor and the real part of ac conductivity were found to be affected significantly with the tuning of anionic moieties of ionic liquids. The ability of materials to store a charge in electromagnetic field was measured. From dielectric and electrical studies, to bring to an end, especially in particular way that the present IL systems have an enormous potential for the designing of modern-day energy storage devices. [ABSTRACT FROM AUTHOR]

A polycrystalline ceramic oxide, BaFe2MnO6 was produced through a regular solid-state route. The phase creation in the synthesized substance was investigated through X-ray diffraction (XRD) technique. The present material has found with made up of a single phase orthorhombic structure. The electrical properties of the compound were recorded through an LCR meter for a broader range of frequencies and temperatures. This perovskite oxide material possesses a large relative permittivity (ɛr = 1139) and low dielectric loss (tanδ = 0.421) at the ambient atmospheric condition, while the curie temperature arise beyond 450 °C. The resultant dielectric properties of this material assure its promising candidature for feasible applications in smart electronic devices such as dielectric material in ceramic capacitors. [ABSTRACT FROM AUTHOR]

In this report, we are presenting the effect of B-site co-doping with Sn and Zr (2% each) on frequency and temperature-dependent dielectric and electrical properties of Ba0.5Sr0.5TiO3 (BST). The desired compound is synthesised following solid-state reaction route and the structural and micro-structural study of the resulting compound is done using X-ray diffractometer (XRD) and scanning electron microscope (SEM) technique. XRD study revealed that the parent structure of BST is mostly retained after co-doping. SEM micrograph analysis presented dense packing of grains of different sizes distributed all over the volume of compound formed. The compound was found to have a moderate value of dielectric constant and low tangent loss along with a near stable response of these dielectric properties over the studied frequency range, suggesting its possible application in tuneable matching networks and frequency agile antennas. Electrical properties study suggested a non-Debye type electrical response with a thermally activated conduction mechanism occurring in the material. The dependence of conductivity with temperature showed negative temperature coefficient of temperature behaviour of the compound and the ac conductivity spectrum followed Johnscher's power law. The variation of exponent with temperature suggested correlated barrier hopping conduction mechanism in the material. [ABSTRACT FROM AUTHOR]

The co-existence of ferroelectric and ferromagnetic properties at room temperature is very rarely observed. In multiferroics, microscopic coupling interaction between the ferroelectric and magnetic order results in the macroscopic correlation between the dielectric and magnetic properties, which is defined as magnetodielectric effect. In this paper, the magnetic behavior of the Pb(Fe1/2Nb1/2)O3ceramics at high temperature has been extensively studied, showing that PFN exhibits ferroelectric and ferromagnetic ordering at room temperature, converting ferroelectric PFN into a multiferroic material at this temperature. [ABSTRACT FROM AUTHOR]

K0.5Na0.5NbO3ceramic prepared by a conventional solid-state reaction process (calcinated at 850°C and sintered) is so fragile that it can not be used to measure dielectric properties. In this paper, we use a two-step calcining method to synthesize KNN composition, with a hydrothermal treatment (200°C for 4 hrs) preceding the calcining process (750°C and 850°C for 2 hrs). Following the hydrothermal treatment and calcining the KNN ceramic was sintered at 1100°C ∼ 1160°C. X-ray diffraction patterns for all KNN ceramics showed a perovskite structure with orthorhombic symmetry. The effects of different calcining and sintering temperatures on the properties of the resulting KNN ceramic, including surface morphology and dielectric characteristic, were recorded and analyzed. [ABSTRACT FROM AUTHOR]

The paper presents synthesis, sintering procedure, microstructure and dielectric properties of a new high permittivity perovskite material relative to Cu2Ta4O12, with the composition Bi2/3CuTa4O12. Impedance spectroscopic studies carried out at frequencies 10 Hz–2 MHz and in a temperature range –55 to 740°C revealed two dielectric responses. The high-frequency and low-temperature response was attributed to grains, and the low-frequency and high-temperature one - to grain boundaries. The high dielectric permittivity was suggested to be related to spontaneous formation of internal barrier layers at the grain boundaries of the semiconducting grains. [ABSTRACT FROM AUTHOR]

The ac conductivity and relaxation mechanism in Ag(Ta,Nb)O3 ceramics have been investigated systematically. The formation of the ceramics was checked by an X-ray diffraction (XRD) technique analysis. The dielectric permittivity and the loss tangent of the Ag(Ta,Nb)O3 specimen were measured in a frequency range from 1 to 100 kHz at the various temperature ranges (30–110°C). A study on dielectric properties reveals the electrical relaxation phenomenon occurs in the material. Studies on the frequency and temperature dependence of ac conductivity of the Ag(Ta,Nb)O3 ceramics suggest that conduction process in the material is thermally activated process. In this paper, we will discuss the dielectric properties and the ac conductivities of Ag(Ta,Nb)O3 ceramics in relation to the electrical conduction process. [ABSTRACT FROM PUBLISHER]

Consolidation parameters have influence and can be used to control structure of BaTiO3 based materials. Microstructure and dielectric properties of Yb2O3 doped BaTiO3-ceramics, sintered from 1320 °C to 1380 °C have been investigated. The correlation between microstructure, capacity and dielectric properties of doped BaTiO3-ceramics, based on fractal geometry and micro-contact surfaces, has been developed. Using the fractal descriptors of the grains contact surface, the microstructure reconstruction constituents, as grains and pores shapes or intergranular contacts, has been successfully done. Obtained results indicated that fractal analysis contact surfaces descriptors of different shapes are very important for the prognosis of BaTiO3-ceramics microstructure and capacity and dielectric properties. The morphology of ceramics grains pointed out the validity of developing new structure analytical methods, based on different grains' shape geometries. The grains contact structure based on Minkowski hull is presented as a new tool for BaTiO3-ceramics materials structure research. The materials properties prognosis are determined according to the correlations synthesis–structure–property, within Minkowski hull fractal frame. [ABSTRACT FROM AUTHOR]

In this paper, single-phase nanocrystalline La1-xSrxFeO3 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) with perovskite structure were prepared by employing sol-gel method. XRD and TEM were used to characterize the materials. Dielectric properties of La1-xSrxFeO3 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) were investigated. The experiments were carried out as a function of Sr doping (0.1 ≤ x ≤ 0.5) and frequency (10-105 Hz) in different relative humidity (RH) at 25°C. The results revealed that capacitance decreased as the frequency increased, and the peaks of dielectric loss appeared at high relative humidity range. Humidity sensing properties were also studied in this work. It was found that La0.7Sr0.3FeO3 exhibited high humidity sensitivity and small hysteresis from 33% RH to 98% RH. [ABSTRACT FROM AUTHOR]

In the present paper, we report low frequency ac conductivity and dielectric studies on the composites of conducting polyaniline (PANI) with crystalline zinc tungstate (ZnWO4) powder. These composites have been synthesized by single step in situ polymerization technique by placing fine grade powder of ZnWO4 during the polymerization of aniline. The composites thus formed were characterized by FTIR spectra and scanning electron microscopy (SEM), which conforms the presence of ZnWO4 in polyaniline matrix and the formation of the composite. AC conductivity and dielectric response of these composites were investigated in the frequency ranging from 50 Hz to 5 MHz. it was found that the ac conductivity obeyed the power law index, where the ac conductivity increases with frequency. PANI/ZnWO4 composites have shown high dielectric constant, which could be related to conductivity relaxation phenomenon. It is observed that both dielectric constant and dielectric loss have decreased with increase in frequency. Variations in measured parameters of AC response with increase frequency of the composites follow systematic trends that are similar to those observed with decreasing temperature and level of doping. [ABSTRACT FROM AUTHOR]

In this paper, ferroelectric Na0.5Bi0.5TiO3 (NBT, in short) was used as additives to improve the permittivities of Ba4.2(Sm0.9,Bi0.1)9.2Ti18O54 (BSBT, in short) solid solutions. X-ray diffraction (XRD) analysis did not reveal any second phases or modification of the BSBT crystal structure. Field emission scanning electron microscopy (FE-SEM) analysis showed typical columnar grains became more rod-like with the increasing amounts of NBT addition. Electron probe microanalyzer (EPMA) results revealed a change of second phases from BaTi4O9 to Ba-Sm-Bi-Ti-O solid solutions with a very long needle shape. The addition of NBT (≤10 wt. %) increased the relative permittivities remarkably while the Qf values decreased. The TCf values increased slightly with the increasing additions of NBT and the sintering temperatures. BSBT doped with 5 wt.% NBT additives exhibited excellent dielectric properties with εr = 90.1, Qf = 5450 GHz and TCf = 0.2 ppm/°C when sintered at 1320°C for 2 hours. [ABSTRACT FROM AUTHOR]

This paper investigated the resistivity and dielectric properties of manganese doped barium titanate sintered in pure nitrogen. The influence of variable doping concentration and Ba/Ti ratio on densification, microstructure, resistivity and dielectric properties was studied. A dielectric with permittivity of 1500 and low dissipation factor of 0.01 measured at 1 kHz, meeting the EIA X7R specification of the Electronic Industries Association standards was obtained in this study. Resistivity of materials sintered in pure nitrogen was 1011∼ 1012Ω cm. Ceramics sintered in pure nitrogen had higher resistivity than ceramics sintered in air, and the resistivity increased with Ba/Ti ratio increasing. [ABSTRACT FROM AUTHOR]

The structural, dielectric and ferroelectric studies of SrBi2Ta2O9 (SBT) ferroelectric ceramics, partially substituted with wolframium (W) for tantalum (Ta), are reported in this paper. Polycrystalline samples of wolframium substituted SBT ceramics of compositions SrBi2(WxTa1 - x)2O9 (SBWT); x = 0.0-0.20 were synthesized by solid state reaction method. X-ray analysis confirm that the single phase layered perovskite structure is maintained up to x = 0.05. The microstructural studies reveal that the average grain size increases with the increase in W- content. Dielectric properties studied as a function of temperature at 100 kHz show an increase in Curie temperature over the composition range of x = 0.025 to 0.20. The dielectric loss reduces significantly with wolframium addition. The temperature dependence of dc conductivity of the samples vis-à-vis wolframium content exhibits the typical negative temperature coefficient of resistance (NTCR) and a decrease in conductivity by as much as two to three orders of magnitude is observed. The ferroelectric properties improved with W-doping and the maximum value of remanent polarization was observed for composition with x = 0.075. The observed results have been discussed in terms of contribution from the cation vacancies which are introduced into the lattice structure so as to compensate the charge imbalance due to donor doping. [ABSTRACT FROM AUTHOR]