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In our earlier studies we have shown procedure for the estimation of activation energy and relaxation times directly from the dielectric and AC conductivity data simultaneously dependant on T and ω using modified Lorentz equation instead of well-known Arrhenius, modified Arrhenius and Vogel-Fulcher laws. In the present paper we have carried out similar experimental and simulation studies on the dielectric and AC conductivity data using modified Lorentz equations on the ceramic compound (Ba0.997Pr0.003TiO3). The obtained results on the activation energy and relaxation times are presented in this paper. [ABSTRACT FROM AUTHOR]

The spark-plasma sintering of ceramics based on the cubic pyrochlore phase in the system Bi2O3-ZnO-Nb2O5 is reported for the first time. It is shown that the use of spark-plasma sintering in the manufacture of (Bi1.5Zn0.5)2(Zn0.5Nb1.5)2O7 ceramics makes it possible to obtain a high density, a homogeneous microstructure, and high dielectric parameters (almost 30% higher compared to conventional ceramic technology). The paper discusses the features of microstructure formation and the optimization of spark plasma sintering regimes. [ABSTRACT FROM AUTHOR]

Synthesis (via solid-state reaction) and characterization (structure, microstructure, dielectric, electrical, and ferroelectric behavior) of brownmillerite polycrystalline material NaBiFe2O5 (NBFO) are discussed in this paper. The formation of a triclinic structure has been analyzed by the X-ray diffraction method. The morphology of the ceramic sample was analyzed using a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray analysis (EDX). It is found that the grains are uniformly distributed through well-defined grain boundaries of the sample containing all the constituent elements (Na, Bi, Fe, and O). The study of both frequency (1 kHz–1MHz) and temperature (25–450 °C) dependent dielectric and AC-conductivity predicts the presence of Maxwell-Wagner type of dielectric dispersion and thermally activated relaxation mechanism of NBFO. The impedance spectra support the semiconducting behavior of the brownmillerite NBFO at high temperature. The resistance of the material falls with a rise in temperature favors the negative temperature coefficient resistance behavior of the material. The study of electric polarization suggests the possibility of the ferroelectric properties of the studied sample. The high dielectric constant and low tangent loss suggest the possibility of the material for device applications. [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]

Synthesis (via solid-state reaction) and characterization (structure, microstructure, dielectric, electrical, and ferroelectric behavior) of brownmillerite polycrystalline material NaBiFe2O5 (NBFO) are discussed in this paper. The formation of a triclinic structure has been analyzed by the X-ray diffraction method. The morphology of the ceramic sample was analyzed using a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray analysis (EDX). It is found that the grains are uniformly distributed through well-defined grain boundaries of the sample containing all the constituent elements (Na, Bi, Fe, and O). The study of both frequency (1 kHz–1MHz) and temperature (25–450 °C) dependent dielectric and AC-conductivity predicts the presence of Maxwell-Wagner type of dielectric dispersion and thermally activated relaxation mechanism of NBFO. The impedance spectra support the semiconducting behavior of the brownmillerite NBFO at high temperature. The resistance of the material falls with a rise in temperature favors the negative temperature coefficient resistance behavior of the material. The study of electric polarization suggests the possibility of the ferroelectric properties of the studied sample. The high dielectric constant and low tangent loss suggest the possibility of the material for device applications. [ABSTRACT FROM AUTHOR]

The paper presents some general patterns of the temperature behavior of thermodepolarization currents, dielectric permittivity and conductivity of dielectric materials containing water molecules or hydrogen bonds – crystallohydrates, polyelectrolytes, and biopolymers. The results indicate that the anomalies of these properties are observed at 4, 20, 35, 46, 65–76°С, which are "threshold points" of water, when its structure changes abruptly. The observed anomalies are probably due to a change in the proton energy at a transition to an excited level in the double-well potential at heating, while the equilibrium of the system is achieved by slow stepwise heating. [ABSTRACT FROM AUTHOR]

The "National Seminar on Ferroelectrics and Dielectrics" (NSFD) is a biennial seminar that has been held in India since 1980. The seminar focuses on the physics, chemistry, and engineering aspects of ferroelectrics and dielectrics, which are materials used in modern technology for applications such as data storage and wireless communications. The 22nd NSFD took place at VIT-AP University in Andhra Pradesh, India, and covered topics including materials design, characterization, and theoretical modeling. The seminar facilitated the exchange of scientific ideas and resulted in the publication of 89 papers in a special issue of Ferroelectrics. [Extracted from the article]

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]

The CaSn0.95Mn0.05O3 (CSMO) was produced by using the sol-gel wet chemical process. The structural composition was examined using an X-ray diffraction (XRD) pattern, and the presence of an orthorhombic structure with the space group Pbnm was confirmed by Rietveld refinement. At different temperatures between 300 K and 773 K, the dielectric permittivity (ε), tangent losses (tanδ), and electrical conductivity of CSMO has been measured as a function of frequency from 100 Hz to 1 MHz.Dielectric permittivity (ε) is found to be independent of temperature up to 400K and very low tangent loss. Jonscher's power law in the material's frequency-dependent ac conductivity shows its semiconductor nature. Optical band gap of CSMO was observed by using UV-vis.absorption spectra. The optical band gap of CSMO, which was determined using Tauc plot measurements to be 2.42 eV, suggests that the sample is a semiconductor. The Arrhenius model is employed to perform an analysis of the dc conductivity of the material concerning both frequency and temperature. As a result of its semiconductivity, stable dielectric constant, and low tangent loss, CSMO is a suitable material for thermally stable capacitors, semiconductor devices, UV filter and UV detectors. [ABSTRACT FROM AUTHOR]

Sol-gel method is used to synthesize the Bi0.90Dy0.10FeO3-BaTi0.95Hf0.05O3 (BDyFO-BTHfO composite) multiferroic composite material. The structural formation was examined utilizing an X-ray diffraction (XRD) pattern preceded by Rietveld refinement utilizing the FULLPROF programme to confirm the presence of tetragonal and partially rhombohedral structures having space group P4mm and R3c, respectively. The dielectric characteristics of the BDyFO-BTHfO composite have been measured with respect to frequency (100 Hz to 1 MHz) and temperature (RT to 663K). Dielectric permittivity (ε) shows low-frequency dispersion which can be addressed by Maxwell-Wanger-type interfacial polarization. The synthesized composite material exhibits a negative magneto-dielectric (MD) effect when a magnetic field is operated (0.0 T to 2.0 T) and the obtained values are −9.61% and −19.68% for the ε and tanδ, respectively, at 1 kHz. The contribution of the grains, grain boundaries and electrode effects on the resistive characteristics of the samples was evaluated using comprehensive impedance spectroscopy using a Nyquist plot. The band gap (Eg) absorption of the synthesized sample was determined using Tauc's formula and found to be 2.05 eV. The BDyFO-BTHfO composite has improved magneto-dielectric, magneto impedance, and optical properties that support their potential usage in microelectronics, energy storage devices, and optoelectronic 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 article, the synthesis (through a mixed oxide route, calcination temperature = 850 °C, sintering temperature = 870 °C, for time= 6 h) and characterization (structure, dielectric, and electrical properties) of Gd modified bismuth titanate Bi4Ti3O12 of a chemical composition Bi3.8Gd0.2Ti3O12 of Aurivillius family in ceramic form have been reported. The development of an orthorhombic structure (with a minor secondary phase) with a space group B2ab has been confirmed by analyzing room temperature X-rays diffraction pattern/data. Studies of some electrical parameters like loss tangent, dielectric constant, electric impedance, and conductivity have provided valuable data and information on conduction mechanism, structure-properties relationship, etc., in the 25–500° C temperature range at different frequencies (1 kHz − 1MHz). The presence of grain, grain boundary is confirmed from the Nyquist plot. The Nyquist plot also confirms the existence of non-Debye relaxation in the material. The frequency and temperature significantly impact the material's various properties (dielectric and electrical). [ABSTRACT FROM AUTHOR]

There are many nanoparticle preparation techniques such as the biological approach sol-gel method and physical methods, etc. However, the co-precipitation approach requires few chemical reagents and reaction time as well as produces highly pure products with comparatively lower costs among the available techniques. In present work co-precipitation method is use to synthesize magnetic iron oxide (Fe3O4) nanoparticles, followed by characterization to check its applicability and the presence of undesired substrate. UV–visible spectroscopy, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Fourier-Transform Infrared Spectroscopy (FTIR) were examined to determine the synthesized Fe3O4 nanoparticles. The nanoparticles' sizes lies between 1 nm to 100 nm, according to the SEM and HR-TEM analyses. XRD measurements verified the crystalline characteristics of the Fe3O4 nanoparticles. Dielectric spectroscopy of synthesized Fe3O4 nanoparticle pellets has been investigated at a wide frequency range 0.1 to 105 Hz. Capacitance and dielectric permittivity of Fe3O4 nanoparticles decrease continuously with frequency as dipole gets less time to orient in the field. The dielectric permittivity of Fe3O4 pellets increases up to 3 mm thickness and subsequently drops, perhaps because a rise in resistance. The electrical conductivity of Fe3O4 rises exponentially with frequency. According to the dielectric studies, the dielectric permittivity and electrical conductivity of Fe3O4 are greatly dependent on the thickness and extent of frequency. Additionally, the dielectric impedance of Fe3O4 pellets has also been investigated as a function of frequency. [ABSTRACT FROM AUTHOR]

The nano-graphite (NG) and acid modified nano-graphite (ANG) have been synthesized from graphite powder via mixture of strong acid (sulphuric acid and nitric acid) respectively by a soft chemistry route involving microwave, ultrasonic method and characterized by high-resolution electron microscopy (HR-TEM), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), clearly demonstrated the successful synthesis of acid modified NG. SEM images confirmed the surface morphology of NG, and ANG and HR-TEM study shows the nanoparticles size of NG and ANG. FTIR data confirmed the presence of acid functional groups on the surface of synthesized NG powder. XRD data of NG and ANG shows that 2θ is at 26.43° and 0.336 nm is an interlayer distance (d). NG and ANG pellets have been prepared for their dielectric analysis with frequency for different thickness. The dielectric loss tangent (tanδ) spectra show relaxation peak with frequency and peak shifts due to presence of polar groups in the ANG. The capacitance values of NG and ANG decrease with frequency and increase with thicknesses due to the capacitive nature of nanoparticles. The dielectric permittivity decreases with frequency and increases with thickness due to the charge orientation and dipole moment change of functional groups of synthesized NG, and ANG. The electrical conductivity of NG and ANG nanoparticles increases with frequency and thickness of NG and ANG pellets due to the conductive nature. Electrical conductivity and dielectric permittivity of NG and ANG are found to highly rely on thickness, according to the dielectric evaluation. [ABSTRACT FROM AUTHOR]

Today, great emphasis is placed on the creation of lead-free compounds that may be used in multi-functional equipment. This report describes the synthesis (through the solid-state technique) and physical characteristics (structural, electrical, and ferroelectric) of a polycrystalline Sr3Bi2WO9 compound (SBWO). A monoclinic crystal structure with cell parameters; a = 9.0285 Å, b = 16.6457 Å, c = 5.6787 Å with β = 93.13° is studied by analysis of X-ray diffraction method (crystallite size 100.77 nm). The purity, morphology, and elementary composition of elements were studied by SEM (grain size 0.582 μm) and EDX. The temperature-frequency variation of εr, tan δ, and σac were investigated. The drop in grain resistance value with increasing temperature demonstrates the NTCR property of the compound. It has been reported that the conduction process of the compound is based on a study of the modulus spectrum. SBWO is a possible choice for devices because it exhibits outstanding temperature-independent εr characteristics and reduced tanδ. Ferroelectric properties of the material (Ec=0.2655 kV/cm, Pr=0.00454 μC/cm2, Emax=2.478 kV/cm, and Pmax=0.0367 μC/cm2) shown by the electric field-dependent polarization at 25 °C. [ABSTRACT FROM AUTHOR]

Polarization rotation and occurrence of monoclinic and triclinic states were investigated in Pb0.1Sr0.9TiO3. For this composition, the rhombohedral ground state may coexist with a tetragonal state close in free energy and become sensitive to electric and mechanical stimuli. The polarization path under an electric field and biaxial strain involves a monoclinic state, while for uniaxial strain the transition involves both monoclinic and triclinic states. Longitudinal and shear piezoelectric constants are enhanced in the induced monoclinic and tetragonal states, respectively. Low-temperature secondary peaks in the literature-reported dielectric spectra can be explained as polycrystalline average of dielectric tensor components of the low-symmetry structures. [ABSTRACT FROM AUTHOR]

Mg0.5-xCuxZn0.5Fe2O4 (where x = 0.0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3) ferrites were synthesized by conventional solid state reaction route and were sintered at 1200 °C using a programmable furnace. These sintered MgCuZn ferrites were characterized by X-ray diffraction (XRD). The single phase of the ferrites was confirmed from the X-ray diffraction studies. The dielectric studies, ac, dc electrical conductivity studies were performed with the variation of Cu content, and temperature. The results are discussed in the light of Koops theory and polaron hopping. [ABSTRACT FROM AUTHOR]

[BaNd0.1Ti0.8Nb0.1O3](1-x)[Na0.5Bi0.5TiO3]x ceramics with x = 0.25, 0.40, 0.60, 0.65 & 0.70 were prepared through solid-state sintering route. In the present study, temperature and frequency dependant dielectric, Impedance, AC resistivity, modulus spectroscopy and electromechanical coupling properties carried out. These materials showed modulus resonance and anti-resonance i.e. electromechanical coupling (M″ vs. frequency). From these modulus resonance and anti-resonance studies piezoelectric charge constant (d33) was obtained. The values of the piezoelectric charge constant (d33) are 3.34 nm V−1, 6.26 nm V−1, 11.58 nm V−1, 14.10 nm V−1 & 10.70 nm V−1 for x = 0.25, 0.40, 0.60, 0.65 & 0.70, respectively. In the present study, the modulus electromechanical was studied in jig with spring which applies constant stress on the ceramic sample. The higher value of electromechanical coupling conversion in the present study may be attributed to this constant applied stress, higher temperature and polarized oxygen vacancies at the crystal lattice at these elevated temperatures (773 K & 873 K). [ABSTRACT FROM AUTHOR]

Pure Li2MnO3 powders were synthesized at 900 °C for 4 h by a solid-state reaction method. Li2MnO3 ceramics were prepared in the temperature range of 1100 °C to 1250 °C. All the samples displayed a single phase structure. The microwave dielectric properties of sintered samples were closely related to sintering temperature and microstructure. The Li2MnO3 ceramics exhibited a well microwave dielectric properties of εr = 12.5, Q × f = 43150 GHz, τf = −9.5 ppm/°C at 1200 °C. [ABSTRACT FROM AUTHOR]

In this study, the structural analysis of the samples (1-x)(K0.44Na0.52Li0.04-Nb0.86Ta0.1Sb0.04)-x(BiAlO3) (x = 0, 0.005, 0.007, 0.01, and 0.05) showed that the samples have orthorhombic and tetragonal phases. The effect of increasing concentration of BA in (1-x)(K0.44Na0.52Li0.04-Nb0.86Ta0.1Sb0.04)-x(BiAlO3) samples have been studied on impedance and modulus analysis of the samples in 100 °C–500 °C temperature range. All the samples were found to exhibit NTCR behavior. AC conductivity showed that the conduction increase with increase in temperature. The dielectric and capacitive behavior of the samples were also analyzed from the dielectric and modulus study of the samples. [ABSTRACT FROM AUTHOR]

The structure of potassium hexacyanoferrate(II) trihydrate (yellow prussiate) contains layers of water molecules between the layers of potassium and ferrocyanide octahedra. When the temperature drops down to 120 K, the water molecules have a tendency to rearrange. The movement of protons in molecular and individual rings occurs in a coordinated manner. The asymmetry of the ring environment leads to a significant decrease of the double-well potential barrier. The theory of coherent correlated motions of protons allows to explain the discreteness of the observed temperature anomalies of dielectric permittivity ε, thermally stimulated depolarization current j, and pyroelectric coefficient γ. [ABSTRACT FROM AUTHOR]

The present study focuses on the effect of Gadolinium (Gd3+) concentration on the lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics synthesised using conventional solid-state reaction method at high temperature (∼1300 ° C). Introducing Gd3+ to the BCZT system influences the properties of the materials. All the compounds were crystallised in tetragonal structure at room temperature. The microstructural study of the compounds has been obtained by scanning electron microscopy (SEM). The frequency and temperature dependent dielectric properties were analysed. The diffusivity of the compounds was investigated using modified Curie-Weiss law. Impedance spectroscopy have been employed for the study of the electrical conduction mechanism. All the compounds display negative temperature coefficient of resistance (NTCR)-type behaviour which indicates its semiconducting characteristic. The existence of non-Debye type relaxation is shown from Nyquist plots. All the synthesised ceramics show enhanced electrical properties which may be utilised in electronic device manufacturing. [ABSTRACT FROM AUTHOR]

1D domain patterning by electron beam in potassium titanyl phosphate crystals covered by an artificial dielectric layer were studied. The polygonal shape of the switched domains elongated along Y-crystallographic direction was obtained. The linear dose dependence of the domain size was attributed to screening of the depolarization field by injected charge. The domain size increase with electron energy is caused by increase in the electron penetration into the resist layer. Formation of an array of nanodomain streamers at the domain wall was observed. Creation of a through 1 D periodical domain pattern with a 10 µm period was demonstrated. [ABSTRACT FROM AUTHOR]

Dielectric tunability of the multicomponent ceramics based on the relaxor ferroelectrics was studied. It was shown that the dielectric behavior in electric field changed significantly during composition-induced crossover from a relaxor ferroelectric to a normal one. A correlation was found between the boundaries of different polar states and the parameters of the dielectric response under electric field. By the example of transition between ergodic relaxor and ferroelectric relaxor, it was shown that the dielectric tunability is a convenient tool that complements dielectric spectroscopy and X-ray diffraction in the construction and refinement of the x-T phase diagrams of relaxor ferroelectrics. [ABSTRACT FROM AUTHOR]

0.9Bi1-xNdxFeO3 − 0.1PbTiO3 solid solution with x = 0.05, 0.10, 0.15 and 0.20 were success fully synthesized by the standard solid-state reaction method. The effect of Nd3+ion substitution on structural, micro structural, ferroelectric, magnetic and dielectric properties of 0.9BiFeO3-0.1PbTiO3 have been investigated. The XRD analysis for the samples under study revealed distorted rhombohedral structure with R3C space group. 0.9Bi1-xNdxFeO3 − 0.1PbTiO3 i.e. (BNFPT)x with x = 0.05, 0.10, 0.15 and 0.20 compounds crystallized as single-phase materials with the same structure as the parent BiFeO3 compound. The SEM study revealed the uniform grain scattering for all prepared samples. Raman spectroscopy showed disappearance of some Raman modes indicated a structural phase transition with substitution of Nd dopants at Bi site and also confirmed the distorted rhombohedral perovskite structure of (BNFPT)x compounds with R3c symmetry. Dielectric measurements reveals that, around Neel temperature, all the samples exhibit magneto-electric coupling and also improved dielectric properties with addition of dopants in BiFeO3(BFO) compound. All the prepared samples exhibit weak ferro-magnetic character at room temperature. However, the variation in linear behavior and enhancement in magnetization is found at 5 K which shows gradual increase in remnant magnetization from 0.00785 emu/g to 0.37513 emu/g with increase in Nd doping for all (BNFPT)x samples. Nd doping reduces leakage current by three orders of magnitude, from 10−4 to 10−7. Ferroelectric study revealed the pinning effect in hysteresis loops with low remnant polarization and coercive field which can be related to the energy storage performance of the samples. [ABSTRACT FROM AUTHOR]