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Sb-modified lithium bismuth titanate Li0.5Bi0.3Sb0.2TiO3 is prepared following the mixed oxide method. The development of a new compound with a single-phase orthorhombic crystal structure is approved from the XRD analysis at environmental temperature. The electrical behavior like dielectric and electrical conductivity are analyzed in a wide temperature as well as frequency range by the impedance analyzer, which exhibits that these properties effectively depend on frequency and temperature. The ac conductivity versus temperatures plots obeys the Arrhenius relation and confirm the presence of the mixed type of conductivity process like space charge conductivity created from oxygen ion vacancies, ionic-polaronic conductivity, and so on, in the sample. Ac conductivity versus frequency spectra is as per Jonscher's Universal Power law. [ABSTRACT FROM AUTHOR]

Sb-modified alkali bismuth titanate Li0.5Bi0.5−xSbxTiO3 (x = 0 and 0.1) compounds are prepared using the method of solid-state-reaction route. The XRD exploration in environmental conditions confirms the development of new compounds having single-phase orthorhombic crystal structures. Non-uniformly distributed grains are noticed in SEM micrographs for both compounds. The electric & dielectric behavior is analyzed by use of an impedance analyzer. The exploration of the dielectric behaviors of both compounds in a wide frequency range (100 Hz–1 MHz) & temperature range (30–500 °C) suggests that these characteristics are strongly dependent on frequency & temperature. Activation energy assessed from temperature variation of ac-conductivity in various zones recommends that the electric transport phenomenon obeys the Arrhenius equation and shows a mixed type of conductivity. [ABSTRACT FROM AUTHOR]

In this paper, detailed studies of effect of small amount of manganese substitution (at the zirconium site) on the structural, micro-structural, and electrical characteristics of lead zirconate titanate of Pb(Zr0.35–xMnxTi0.65)O3;x = 0, 0.02, 0.06, 0.10 (PZMT)) have been reported. The materials were prepared by using standard ceramic technology. The formation of the compounds and their basic crystal data have been studied through X-ray diffraction (XRD) method. The crystallite size and lattice strain of the compounds, evaluated from Scherrer's and Hall Williamson (H-W) equations, is found to be in the range of 40–50 nm and 11 × 10−4 to 50 × 10−4, respectively. Microstructures of different magnifications, revealing the surface nature of the compounds, have been recorded by field emission scanning electron microscope (FESEM). Effect of Mn+4 ions on electrical behavior (electrical impedance (Z*), electrical modulus (M*), conduction and relaxation phenomenon) of PZMT systems, over wide range of temperature and frequency, has been studied. [ABSTRACT FROM AUTHOR]

The current communication addresses structural, impedance, conductivity, dielectric permittivity, tangent loss, and ferroelectric hysteresis of selenium doped bismuth titanate (Bi4Ti2.9Se0.1O12) synthesized by a solid-state reaction technique. XRD profile reveals the formation of orthorhombic unit cell structure (B2ab space group) in Bi4Ti2.9Se0.1O12. Partial doping of Se (10%) makes significant modifications in the electrical and dielectric characteristics, which are investigated over discrete frequencies (1 kHz–1 MHz) and temperatures (27–300 °C). The compound exhibits comparatively low value of the tangent loss at 1 MHz frequency. The ferroelectric hysteresis loop of the compound confirms the non-centrosymmetric arrangement of elements at room temperature, and the value of remanent polarization makes the compound suitable for memory applications. [ABSTRACT FROM AUTHOR]

The structural, dielectric and transport properties of modified Bismuth Sodium Titanate (BNT) are reported. Mn and Sr-modified BNT (Bi0.35Na0.35Sr0.3Ti0.9Mn0.1O3) was synthesized by a solid-state reaction route. Structural analysis based on Rietveld refinement of X-ray diffraction data confirms the single-phase characteristic without change of hexagonal crystal structure with R3C space group of BNT. The dielectric characteristics of the modified BNT are recorded in the frequency range of 20 Hz to 1 MHz at temperatures of 50 °C and 200 °C. Using the frequency-dependent, real and imaginary parts of the dielectric constant, ϵ′(ω)-ϵ″(ω) dipolar and hopping conduction-based carrier polarization properties are discussed. The dipole parameters such as relaxation time, static and high-frequency dielectric constant etc. are estimated by using Cole-Cole relaxation model. [ABSTRACT FROM AUTHOR]

This communication reports the effect of Iron (Fe) and Lithium (Li) co-doping on the structural, dielectric and electrical properties of Ba0.8Sr0.2TiO3; i.e. (Fe0.5Li0.5)0.1Ba0.7Sr0.2TiO3 (FLBST). The FLBST composite was synthesized by the solid-state mixed oxide method at 1400 °C for 12h. The crystalline phase formation has been confirmed by the X-ray diffraction technique and analyzed through the Rietveld Analysis using X'Pert Highscore plus software. From the XRD analysis, lattice parameters and the average crystallite size was calculated. The electrical properties of sintered (at 1450 °C for 2h) pellets were carried out in the temperature range of 30 °C–350 °C using impedance spectroscopy. Based on the real and imaginary part of the dielectric constant, i) the dipolar contribution which is dominant in 30 °C–150 °C is characterized by Curie-Weiss law and ii) contribution from defects and oxygen vacancies seen beyond 150 °C is described by Arrhenius equation. [ABSTRACT FROM AUTHOR]

The current communication addresses structural, impedance, conductivity, dielectric permittivity, tangent loss, and ferroelectric hysteresis of selenium doped bismuth titanate (Bi4Ti2.9Se0.1O12) synthesized by a solid-state reaction technique. XRD profile reveals the formation of orthorhombic unit cell structure (B2ab space group) in Bi4Ti2.9Se0.1O12. Partial doping of Se (10%) makes significant modifications in the electrical and dielectric characteristics, which are investigated over discrete frequencies (1 kHz–1 MHz) and temperatures (27–300 °C). The compound exhibits comparatively low value of the tangent loss at 1 MHz frequency. The ferroelectric hysteresis loop of the compound confirms the non-centrosymmetric arrangement of elements at room temperature, and the value of remanent polarization makes the compound suitable for memory applications. [ABSTRACT FROM AUTHOR]

Crystal structure and Dielectric properties investigation of lead-free Bi0.35Na0.25Li0.1Sr0.3TiO3 (BNLST) composite is reported. The required solid solution was synthesized using oxides and carbonates via the solid-state reaction method. The stoichiometrically weighed and mixed powder was calcined at 800 °C for 12 h, and the pellets were sintered at 1250 °C for 2 h. XRD measurements confirm the formation of single-phase rhombohedral perovskite structure and the crystal structure was refined using the X'Pert High-score plus software. The full-width half maxima of the XRD peak was used to compute the average crystallite size employing the Debye-Scherrer, Williamson-Hall, and Halder-Wagner techniques. The BNLST's dielectric measurements were performed as a function of temperature at five distinct frequencies in the range of 100 Hz–1 MHz. The phase transition temperatures are shifted toward room temperature with the doping of Li and Sr. The diffuseness parameters of the phase transition, the a.c. electrical conductivity and the activation energy are estimated for the BNLST composite. [ABSTRACT FROM AUTHOR]

In the present work, pure and bismuth-doped barium titanates have been prepared using the sol-gel method. The chemical formula used for the synthesis of bi-doped barium titanate is Ba1-xBixTiO3, where the values of x have been chosen to be 0.00, 0.05, 0.075, 0.10, and 0.15. Barium acetate [Ba(CH3COO)2] and titanium (IV) isopropoxide [Ti{OCH(CH3)2}4] have been used as barium and titanium precursors, respectively. For bismuth doping, bismuth (III) nitrate pentahydrate [Bi(NO3)3)5H2O] has been used. The paper discusses the preparation mechanism, tolerance factor, and the thermal characterization (TGA/DSC) results of pure and bi-doped barium titanate ceramics. [ABSTRACT FROM AUTHOR]

The structural and dielectric properties of magnesium titanate solid solutions substituted with zinc or cobalt (MxMg1-x) TiO3 (M=Zn/Co and x=0.00, 0.05) were investigated. MgTiO3 formed as a single phase, according to X-ray diffraction analysis. Low porosity, tightly packed grains were detected using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses. The dielectric properties reveal that (MxMg1-x) TiO3 with Zn = 0.05 shows a good combination of relative permittivity (ɛr) of 15.10, loss tangent (tan) of 1.11×10-3, and temperature coefficient of resonant frequency (τf) of -42.70ppm/°C at 1MHz was reported. [ABSTRACT FROM AUTHOR]

In order to realize the preparation of environmentally friendly piezoelectric ceramic coatings on the surface of metallic materials, sodium bismuth titanate (Bi0.5Na0.5TiO3, BNT) ceramic coatings were prepared by supersonic plasma spraying. The surface morphology, cross-sectional morphology, phase structure, and elemental valence variations of the BNT coating were examined, as well as the dielectric and ferroelectric properties of the BNT coating. The results show that the coating has a good quality and a single perovskite structure. The dielectric constant was stable at about 425 and the dielectric loss was stable at about 0.06 when the test frequency reached 200 kHz. The coating exhibits good hysteresis lines under different applied electric fields. When the applied electric field was 40 kV/cm, the remnant polarization value of the prepared coating was 11.47 mC/cm². It can be seen that the BNT piezoelectric coating prepared by supersonic plasma spraying has good ferroelectric and dielectric properties, which lays a solid foundation for in-situ monitoring of environmentally friendly lead-free BNT piezoelectric coating. [ABSTRACT FROM AUTHOR]

This work presents the impact generated energy harvesting characteristics of cement/lead zirconate titanate (Pb(Zr0.52Ti0.48)O3; PZT) composites. A soft grade PZT (SP 5 A) with ∼1 µm sized particles in an unpoled state was utilised to prepare cement/PZT composites. The experiments were performed on 28 days' water cured unpoled samples. The total cumulative volume and average pore radius are observed to decrease with PZT concentration in the composite. The values of piezoelectric coefficient and capacitance were, respectively, found to increase by 300 and 275% for cement/PZT composites consisting of 40% PZT compared to that of 5% added PZT. The impact generated voltage and energy increases significantly with increasing PZT-content. The voltage generation from cement/PZT could be because of the oscillations of dipoles and the mobility of ions in the pores of the hydrated cement. The results obtained foreshadow the prospect of utilising cement/PZT composites for energy harvesting from civil structures, structural health monitoring, and as sensors. [ABSTRACT FROM AUTHOR]

Calcium Copper Titanium Oxide (CCTO) Ceramics of composition CaCu3Ti4O12 has emerged as a lead-free ceramic supercapacitor with a large dielectric constant of 104–105 at room temperature. The CCTO microstructure is electrically heterogeneous composed of semiconducting grains and insulating grain boundaries. The origin of the large dielectric constant has therefore been widely attributed to barrier layer capacitance originated at grain boundaries. Our research is focused on understanding the stability and reproducibility of the measured electrical and dielectric properties when they are used as capacitor dielectrics because of the inconsistent results obtained when tested in ambient conditions. The origin of this inconsistency is investigated through the roles of testing atmosphere, sample thickness and doping with alumina on the stability and reproducibility of dielectric properties of CCTO. The solid state reaction method is used to fabricate phase pure and dense samples. AC impedance spectroscopy is used to study the roles of testing atmospheres, temperatures, microstructures, grain boundaries, sample thickness, alumina doping and frequency on the dielectric properties. It is shown that this approach of characterizing fundamental electrical properties of CCTO can be used to eliminate hysteresis to produce stable and reproducible dielectric properties. These perspectives are presented and discussed. [ABSTRACT FROM AUTHOR]

lithium titanate (LTO), which has spinel structure, has become one of the most popular anode materials for lithium-ion batteries because of its high safety and stability. In this paper, industrial metatitanic acid and lithium hydroxide were used as the main raw materials to prepare nanotube LTO materials by two-step hydrothermal method. The effects of different titanium sources, stirring speed, hydrothermal reaction temperature and time, li-ti molar ratio and other process parameters on the phase, morphology and electrochemical properties of the samples were studied. The experimental results show that the nanotube LTO electrode material can be prepared by stirring at 300 rpm, reacting at a hydrothermal temperature of 170 °C for 20h, controlling the lithium titanium molar ratio of 0.85, and finally calcining; The specific capacity of nanotube LTO reaches 150mah/g at 10 C high magnification, and the capacity retention rate of 500 cycles is more than 92%. Compared with ordinary LTO materials, nanotube LTO has obvious performance advantages and excellent comprehensive electrochemical performance. [ABSTRACT FROM AUTHOR]

Influence of (K0.5Bi0.5)TiO3 (KBT) dopants on crystal and microstructure, ferroelectric and dielectric properties of ceramic composition from morphotropic phase boundary in the system (1–x–y)(Na0.5Bi0.5)TiO3 – xBaTiO3 – y(K0.5Bi0.5)TiO3 (x = 0.06, y = 0–0.15) additionally modified by ZnO additives was studied using a complex of methods. Changes from 42.8 nm to 62.6 nm of the volume-weighted crystallite size distribution function G(L) corresponding to coherent scattering regions were observed. The microstructure and the second harmonic generation data indicated a change in the relative content of polar nanoregions in tetragonal nonpolar matrix. Decrease in temperatures of phase transitions Tm and Td was observed with KBT concentration increasing. [ABSTRACT FROM AUTHOR]

Influence of dopants on structure, microstructure, dielectric and ferroelectric properties of ferroelectric-relaxor (Na0.5Bi0.5)TiO3 ceramics modified by Ba2+ cations and overstoichiometric additives (SiO2 and Na2O) was studied. Changes in structure, microstructure, and dielectric parameters were observed depending on solid solutions compositions. [ABSTRACT FROM AUTHOR]

Thin polycrystalline lead zirconate titanate (PZT) films with a Zr:Ti ratio close to morphotropic phase boundary were obtained by radiofrequency sputtering at a temperature of 540 °C on a metal substrate, and their structural and electrophysical properties were studied. The piezoelectric coefficient, remnant polarization, coercive field, and dielectric constant of the PZT film are 3.84 μC/cm2, 1.20 ÷ 1.26 μC/cm2, 1.1 ÷ 1.3·105 V/cm, and 145, respectively. Domains of the perovskite phase are located on the surface of the film protrusions. The magnitude of the piezoelectric modulus of the domain is 17.9 ÷ 22.4 pC/V. [ABSTRACT FROM AUTHOR]

Phase transitions in PbZrO3 (PZ), PbTiO3 (PT), and solid solutions of Pb(Zr1-xTix)O3 system were studied by dilatometric method. The temperature dependence of thermal expansion and linear coefficient of thermal expansion for both single crystals and ceramic samples exhibit several anomalies corresponding to phase transitions of different origin and correlate to the results of X-ray diffraction studies. The obtained results should be taken into account for development of materials and devices based on the studied solid solutions of Pb(Zr1-xTix)O3 system. [ABSTRACT FROM AUTHOR]

The effect of pressure of pelletisation on the density, microstructure, dielectric, ferroelectric, piezoelectric and energy storage density of B-site Zr doped barium titanate has been studied. X-ray diffraction confirmed that zirconium form complete solid solution with barium titanate. It has been observed that 4 ton/cm2 is an optimum pressure of pelletisation which gives maximum density, maximum dielectric constant, maximum piezoelectric constant and high energy storage density with efficiency of 67.68%. There is a good correlation among the density, grain size, dielectric, ferroelectric and piezoelectric properties. These results suggest that this material has a potential for energy storage applications. [ABSTRACT FROM AUTHOR]

The experimental and simulation of dielectric, AC resistivity and dielectric resonance and anti-resonance data on (Na0.5Bi0.5)(NdxTi1-2xNbx)O3] ceramics were carried out using modified Lorentz equations as proposed by us instead of well know and generally applied laws like Arrhenius law and formulas on piezoelectricity to obtain activation energy, relaxation time, piezoelectric charge constant and voltage constant directly from the experimental data. The piezoelectric charge constant (d33) evaluated from the modeling are 864.64 p.m/V and 122.40 p.m/V; whereas the piezoelectric voltage constant (g33) are 10.88 p.m2/C and 8.55 p.m2/C for x = 0.0125 and 0.025 ceramic samples, respectively. [ABSTRACT FROM AUTHOR]

The in situ detection of the damaged aluminum alloy plate with bolted patch is numerically and experimentally studied based on a surface-mounted piezoelectric ceramic lead zirconate titanate (PZT) elements. The contact effects between the bolts, repair patch and host structure are considered. The convergence analysis, range-frequency analysis and pretension force analysis are discussed. The numerical results are good agreement with those of the experiments. The damage identification indexes are introduced for damage detection. It indicates the numerical simulation is effective for the damage deterioration of bolted repaired structures. The location of the PZT transducer is discussed to optimize the process. [ABSTRACT FROM AUTHOR]

The effect of substitution of lithium cations in the sublattice A of sodium bismuth titanate on the parameters of the crystal structure, microstructure, dielectric and local piezoelectric properties of ceramics [(Na0.5Bi0.5)1-xLix] TiO3 with x = 0 ÷ 0.1 has been studied. Modified samples have been characterized by phase transitions manifesting themselves in the form of peaks of permittivity near ∼600 K. An increase in the value of the piezoelectric coefficient d33 at x ≥ 0.08 has been established, which correlates with an increase in the value of dielectric permittivity at room temperature. [ABSTRACT FROM AUTHOR]

Results of calorimetric and dielectric studies of ferroelectric composite (C6H16NBr)1-x/(PbTiO3)x (x = 0.1, 0.2, 0.3) are presented. It was shown that addition of lead titanate leads to a change of the sequence in structural phase transitions in diisipropylammonium bromide. In the temperature range 423–411 K, two phases of C6H16NBr (ferroelectric P21 and non-ferroelectric P212121) are coexist. It was found that their ratio depends on the lead titanate content. [ABSTRACT FROM AUTHOR]

At the isothermal annealing below the crystallization temperature, dependences of the internal friction on time for the thin-film nanogranular composite consisting of crystalline nickel (Ni) and an amorphous material based on lead zirconate titanate [Pb0.81Sr0.04(Na0.5Bi0.5)0.15][(Zr0.575Ti0.425)]O3 have been studied. We have observed a relaxation in the amorphous phase of the composite. The structural relaxation studied is irreversible and thermally activated, and dependences of its parameters on temperature and the Ni content are discussed in terms of the model of stress relaxation in local regions of the amorphous material. [ABSTRACT FROM AUTHOR]

The purpose of this work is to study the effect of rapid thermal annealing (RTA) with halogen lamps on the structural and phase characteristics of lead zirconate-titanate (PZT) films. The PZT thin films with a thickness of 1.0 ± 0.1 μm were deposited by high-frequency reactive plasma sputtering in an oxygen atmosphere on oxidized silicon and silicon substrates with orientation (100). After deposition, the PZT films subjected to RTA at temperatures of 500 °C, 600 °C and 700 °C at a rate of 60 °C/s. The structural-phase composition of PZT films was determined with X-ray diffraction analysis. Studies of heterostructures with scanning electron microscopy methods have shown that increase in the temperature of the RTA leads to a qualitative change in the structural-phase state of the PZT film as compared to its initial state. This makes it possible effectively using of RTA in the formation of PZT films with specified parameters. [ABSTRACT FROM AUTHOR]

Effects of cation substitutions on crystal structure parameters, microstructure, dielectric and ferroelectric properties of ceramic solid solutions (Na0.5Bi0.5)(Ti1-xMgx)O3 with x = 0 ÷ 0.1 were studied. Phase transitions near 400 K demonstrate a pronounced relaxor behavior typical for (Na0.5Bi0.5)TiO3 (NBT) based compositions conditioned by presence of polar nanoregions in nonpolar matrix. Changes in the perovskite structure parameters, microstructure, and functional properties of Mg2+ modified NBT ceramics confirmed the influence of the acceptor dopant amount on their properties. Increase in total conductivity at high temperatures and effects of dielectric relaxation were observed with increasing amount of magnesium cations indicating enhancement of ionic conductivity. [ABSTRACT FROM AUTHOR]

Effects of cation substitutions on crystal structure parameters, microstructure, dielectric and ferroelectric properties of ceramic solid solutions (Na0.5Bi0.5)(Ti1-xMgx)O3 with x = 0 ÷ 0.1 were studied. Phase transitions near 400 K demonstrate a pronounced relaxor behavior typical for (Na0.5Bi0.5)TiO3 (NBT) based compositions conditioned by presence of polar nanoregions in nonpolar matrix. Changes in the perovskite structure parameters, microstructure, and functional properties of Mg2+ modified NBT ceramics confirmed the influence of the acceptor dopant amount on their properties. Increase in total conductivity at high temperatures and effects of dielectric relaxation were observed with increasing amount of magnesium cations indicating enhancement of ionic conductivity. [ABSTRACT FROM AUTHOR]

Ba(NdxTi1-2xNbx)O3 (with x = 0.025, 0.05, 0.1, and 0.2) and Na0.5Bi0.5(NdyTi(1-2y)Nby)O3 (y = 0.0125, 0.025, and 0.05) ceramics were prepared through solid state sintering route. In the present study modulus resonance studies at high temperatures were carried out on the above ceramics. Higher piezoelectric performance in terms of parameters like thickness mode of electromechanical coupling factor and piezoelectric charge constant were observed for the ceramic compositions operating at higher temperature regime (798–873 K). In the case of ceramic composition with y = 0.0125, 0.025, and 0.05, the piezoelectric charge constant operating at 798K are 26.16 nm.V−1, 17.74 nm.V−1, and 24.33 nm.V−1, respectively. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics of bismuth sodium potassium titanate doped with a modified barium titanate (BNKT-xBTNb, x = 0.00–0.06) were prepared via the solid-state reaction process. The effect of BTNb on the phase formation, mechanical, dielectric, ferroelectric, and piezoelectric properties was investigated and discussed. All ceramics have a single perovskite phase. The data also revealed that there was a transformation from rhombohedral (x = 0.00) to mixed tetragonal/rhombohedral phases (0.02 ≤ x ≤ 0.04.), then to tetragonal-rich phases at x = 0.06. Microstructure analysis also indicated that the BTNb affected the morphology of the microstructure, where the average grain size decreased with increasing BTNb content. The BTNb doping produced an enhancement of mechanical properties, HV and HK increased with increasing BTNb content and reached the maximum values of 6.28 GPa, 5.51 GPa for x = 0.04 sample, respectively. The improvement of the properties was related to the change in microstructure. Furthermore, dielectric enhanced with increasing BTNb content, which reached a maximum value of 5439 for the x = 0.06 sample. However, the BTNb doping produced slimmer P-E loops which decreasing of Pr and Ec values. Meanwhile, the undoped BNKT displayed a highest piezoelectric coefficient, d33 of 198 pC/N. [ABSTRACT FROM AUTHOR]

The spinel type Li4Ti5O12 was prepared by high temperature solid-state reaction, using metatitanic acid and lithium titanate as raw materials, the influence of calcination temperature and time on the structure of the material was investigated. Li4Ti5O12 was used as raw material, and the carbon coating of Li4Ti5O12 was studied by adding glucose, the effect of temperature and time of the second calcination on the structure of the product was investigated. The structure was characterized by XRD. Selected the product with the highest C content for SEM, TEM, electrochemical performance testing. The results show that the product crystallized at a Li:Ti ratio of 0.85 and calcined at 750–800 °C for 6 h is crystallized and uniformly dispersed. The lithium titanate composite material with good dispersity, particle size of 1–5 μm and carbon content of 0.052% was successfully prepared under the conditions of 25% glucose and calcination at 750 °C for 2 h, the modified lithium titanate has a good charge-discharge capacity of more than 170 mAhg−1. [ABSTRACT FROM AUTHOR]

In this paper, studies on the preparation and properties of barium sodium titanate niobate and poly(vinylidenefluoride) (PVDF) bulk composites are reported. SEM images show ceramic particles incorporated into the PVDF matrix in a 0–3 connectivity. FTIR results reveal that BTNN was formed without undesirable phases and that the β-phase of polymer is present. Dielectric studies show a relaxor ferroelectric behavior with a real dielectric constant of ∼56 (300 K at 1 kHz) and a maximum dielectric loss of 7%. This value is the highest among those reported for PVDF-ceramic composites with 30% of ceramic phase in their matrices. [ABSTRACT FROM AUTHOR]

Ba1−xPbxTiO3/Y3Fe5O12 particulatecomposites with х = 0-1 were synthesized. The composites (100-y) wt.% Ba0.9Pb0.1TiO3 - y wt.% Y3Fe5O12 with у = 40-50 wt.% exhibit ME coupling coefficient ΔЕ/ΔH of ∼10 mV/(cm·Oe) due to the prominent piezoelectric properties. ME response in Ва1−хPbxTiO3/Y3Fe5O12 ceramics with х = 0.35−1 is precluded by a high content of pyrochlore-type Y2Ti2O7 that forms through chemical interfacial interaction. An increase in sintering temperature to 1300°С was found to be inappropriate to obtain phase-pure ВаTiO3/Y3Fe5O12 ceramics due to the partial decomposition of Y3Fe5O12 to yttrium orthoferrite YFeO3. [ABSTRACT FROM AUTHOR]

Microcrystals of several perovskite titanates (ATiO3, A:Pb, Mn, Ni, Co, Mg) have been synthesized by the corrosion product method. The products were characterized by XRD, SEM, and Micro-Raman scattering. The average size of the microcrystals is estimated to about 2 μm by the scanning electron microscope. Micro-Raman scattering spectra show the typical line shapes corresponding to the crystal structures of ATiO3. In the trigonal MgTiO3, the intensities of the several Raman modes take the maximum value at 50°C as temperature increase from room temperature. It is indicated that the peaks are caused by the impurities rather than the structural change. [ABSTRACT FROM AUTHOR]

Lead Hafnate-Titanate, Pb(Hf0.3Ti0.7)O3(PHT), films were fabricated by PLD on Al2O3(0001) substrates with Pt or SrRuO3(SRO) bottom electrodes, respectively. There is a certain amount of pyrochlore phase in PHT films on Pt/Al2O3. In contrast, the PHT films on SRO/Al2O3show pure pervoskite phase. Furthermore, the PHT thin films on SRO/Al2O3, show uniform gain size and significantly enhanced ferroelectric properties with larger remnant polarization (2 Pr = 59.1μC/cm2), better fatigue endurance and lower leakage current density (8.5 × 10−8A/cm2at 150 kV/cm). With the enhanced properties, PHT ferroelectric film on SRO electrode could be a promising structure which can be applied in FeRAM. [ABSTRACT FROM AUTHOR]

Description of the local symmetry of relaxor ferroelectrics, especially in connection with nature of polar nanoregions, is one of the key questions in research of relaxor ferroelectrics. Unlike such well-known relaxor ferroelectrics as PbMg1/3Nb2/3O3and (Pb,La)(Zr0.65Ti0.35)O3, ternary solid solutions 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3show clear coexistence of phases of tetragonal and cubic symmetry, which is established by x-ray diffractometry. Since the second-harmonic generation spectroscopy is a sensitive tool in determination of deviation from symmetry, containing a centre of inversion, it is used as an additional method in characterization of structure in 0.4Na1/2Bi1/2TiO3-(0.6-x)SrTiO3-xPbTiO3. Measurements indicate low, increasing intensity of the second-harmonic generation upon decreasing of temperature, for the samples with low concentration of PbTiO3. Whereas an abrupt change is observed at the phase transition between ferroelectric and relaxor states for the samples with higher concentrations of PbTiO3. [ABSTRACT FROM AUTHOR]

The atomic-scale structure of Ti-related perovskite materials, ATiO3(A= Sr, Ba, Pb), has been studied using high-energy X-ray diffraction, Rietveld refinement, and the atomic pair-distribution function technique. It was found that the local structures of BaTiO3and PbTiO3deviate from their average structures. We also found the tetragonal distortion in their middle-range-order structures (∼ 7 Å). The temperature dependence of the middle-range-order structures showed that an order-disorder character exists in BaTiO3and a displacive-type character exists in PbTiO3. [ABSTRACT FROM AUTHOR]

Barium hafnate titanate (BaHf0.1Ti0.9O3) ceramics are sintered using conventional (CS) and microwave (MS) methods. The XRD patterns show that the ceramics have a single phase perovskite structure without evidence of any additional phase. The grain size of ceramics prepared by MS is much smaller than that of the ceramics sintered by CS. It is shown that the dielectric constant of the conventionally sintered ceramics is larger than that of the microwave-sintered samples, which may be caused by the larger grain sizes of the former compared with the latter. However, the dielectric loss of the microwave-sintered BaHf0.1Ti0.9O3ceramics is larger than that of the conventionally sintered samples. In the range of 30–140°C, there aren't obvious peaks in the dielectric constant-temperature and dielectric loss–temperature curves. It is found that the remanent polarization and coercive electric field of BaHf0.1Ti0.9O3ceramics prepared by MS are much smaller than that obtained by CS. [ABSTRACT FROM PUBLISHER]

Lead magnesium niobate titanate (PMNT) and Portland cement (PC) composite were fabricated as a new cement-based piezoelectric composite. Scanning Electron Microscope and Piezoresponse Force Microscope were used to investigate the morphology and domain configurations at the interfacial zone of PMNT-PC composites. Angular PMNT ceramic grains were found to bind well with the cement matrix and PMNT grains can be seen to disperse randomly in the cement matrix. Moreover, the angular shape PMNT particle contributes to better mechanical interlocking with the cement paste due to the angular aggregate having rough surface appearing to provide better mechanical interlocking with the cement paste. [ABSTRACT FROM AUTHOR]

Spherical monosized barium zirconate titanate nanoparticles (Ba(ZrxTi1−x)O3(BZT) when x = 0.25, 0.30 and 0.35) have been prepared by co-precipitation in a strongly alkaline solution (20 M NaOH) at 80°C. The phase formation of the as-precipitated powders was characterized by XRD, FT-IR and Raman spectroscopy as a single-phase BZT with cubic perovskite oxide structure. This indicates that crystalline BZT powders can be obtained from the co-precipitation in 20 M NaOH without the requirement of calcination process. SEM analysis showed that BZT had nanosized spherical morphology with uniform shape and size. The crystal sizes obtained by TEM analysis were 20-40 nm. [ABSTRACT FROM AUTHOR]

A series of polycrystalline Ga-doped Barium titanate (BaTi1-xGaxO3) were synthesized for the studies on the dopant-concentration dependence of Raman spectra and dielectric properties. The Qx f value of Ga-doping samples increases up to about 20% of Ga concentration, but the dielectric constant (K-value) decreases while the A1gphonon mode (636 cm−1) experiences an increasing red-shift. The phonon mode becomes soft with Ga-ion increasing, and the FWHM of Raman peak increases with Ga-ion increasing until tetragonal structure appeared. The effective ionic weight, ionic radii and Coulomb interaction are important influences, which induce the chemical pressure and reduce the excess charge in Ti-site in the Ga-doping h-BaTiO3system. The relation between Raman mode shifter and K-value, and the correlation of the Qx f value and the FWHM of related phonon vibrations have been reported and examined. [ABSTRACT FROM PUBLISHER]

Ferroelectrics with high TC > 600 K attract much attention due to prospects of their applications at high temperatures. In this work, influence of partial substitutions on the crystal structure and dielectric properties of lead-free bismuth oxides Ca(Bi1-x Nd x )4Ti4O15 (x = 0, 0.1) have been studied. Ceramic solid solutions have been prepared by the solid state reactions. Optimal temperatures of synthesis and sintering of the samples were determined. Phase composition, structure and microstructure of the samples were studied using the X-ray diffraction and scanning electron microscopy methods, respectively. Phase transitions and ferroelectric properties were studied by the dielectric spectroscopy. Positive effect of the Mn2O3 and Bi2O3 additives was proved. They favor to improving density of ceramics, inhibiting grain growth and to decreasing dielectric loss. [ABSTRACT FROM AUTHOR]

Two photo-induced phenomena have been newly discovered in Bi4-xLaxTi3O12 (BLT0.41). One of them is”photo-darkening phenomenon (PD)”; the laser illuminated area turns black below T = 390°C, where the wavelength of the laser is 514.5 nm. The other is”photo-erasable memory phenomenon (PEM)”; the blackened area produced by the PD becomes transparent when the same laser is illuminated on the other area where is d = 80 μm away from the blackened area. The PEM is found to occur in the temperature range between 230°C and 390°C in case of d = 80 μm and in the distance range of d <100 mm at T = 250°C. Since these phenomena do not occur in pure Bi4Ti3O12, the La3+ ions must play an important role. [ABSTRACT FROM AUTHOR]

Textured Li0.95Nb0.45Ti0.7O3 (LNT) microwave dielectric ceramics were fabricated by the screen-printing templated grain growth technique (sp-TGG). The plate-like LNT particles with diameters of 5–20 μm and thicknesses of 0.5–2.0 μm prepared by molten salt synthesis (MSS) were chosen as templates. The <110> oriented LNT ceramics with an orientation degree of 73% were fabricated via the sp-TGG method. The dielectric anisotropy was observed in LNT(//) and LNT(⊥) samples. At microwave frequency, the LNT(//) sample exhibits ϵ r = 47, Q×f = 9893 GHz, τ f = −18 ppm/°C, whereas the LNT(⊥) sample exhibits ϵ r = 75, Q×f = 6942 GHz, τ f = 52 ppm/°C. [ABSTRACT FROM AUTHOR]

In this paper we report the mechanism and nature of relaxor ferroelectric behavior in the environmental friendly lead free Barium Zirconate Titanate (BZT) system. A revised complete (Structure:Property) phase diagram of Ba(ZrxTi1-x)O3, with compositions 0.00≤ × ≤1.00 has been developed based on their electrical properties. Two different kinds of relaxor behaviors have been observed in the BZT system; one is dominated by polar Ti-rich regions and another by non-polar Zr-rich regions. All the BZT relaxor compositions are characterized by dielectric properties with and without bias, pyroelectric and thermal expansion measurements in the wide range of temperatures. The structure of the BZT compositions has been evaluated by XRD, Neutron diffraction study. Further the local structure of the BZT compositions has been probed by micro-Raman spectra. Although the global structure of BZT relaxors is cubic as observed in Neutron diffraction studies, the local symmetry is non-cubic as evident in the micro-Raman spectra of BZT relaxors as well as in their thermal strain measurement, dielectric and pyroelectric behavior. [ABSTRACT FROM PUBLISHER]

In order to develop lead-free composition ceramics for piezoelectric actuator, sensor, and transformer applications, (1-x)[Li0.04(Na0.54K0.46)]0.96(Nb0.84Ta0.10Sb0.06)O3 + x(Bi0.5Na0.5)TiO3 (x = 0∼2 mol%) composition ceramics were fabricated by a conventional sintering technique. The influences of (Bi0.5Na0.5)TiO3(abbreviated as BNT) on the microstructure, the dielectric, ferroelectric and piezoelectric properties of the ceramics were investigated. The crystal structure of specimens with x = 0 mol% exhibited an orthorhombic structure. However, at the compositions more than 0.5 mol%, the crystal structure showed tetragonal structure. The temperature dependence of dielectric constant showed that Curie temperature decreased with the increase of BNT substitution content. At room temperature, the ceramics substituted with 1 mol% BNT had a piezoelectric constant d33 = 222.6 pC/N, electromechanical coupling factor kp = 0.36, mechanical quality factor Qm = 78 and dielectric constant ϵr = 1570, respectively. [ABSTRACT FROM PUBLISHER]

Glasses of compositions (50 -X) PbO-X CaO-25 TiO2-25 B2O3 (where X = 0,5,10 and 15 mol%) were prepared by conventional quenching technique. The glass samples were converted to glass ceramics by two stage heat treatment schedule. The XRD results confirmed the formation of ferroelectric PbTiO3 as a major phase in the glass ceramics. For all the CaO added samples the dielectric constant as a function of temperature, exhibit a peak around 475°C, which is close to the Curie temperature of PbTiO3. The hysteresis measurement supports the ferroelectric nature of the glass ceramics. [ABSTRACT FROM PUBLISHER]

This paper describes the formation of poled bulk ferroelectric ceramics made of Lead Lanthanum Zirconate Titanate (PLZT) and Barium Titanate (BaTiO3). These ceramics were implanted during their fabrication with a platinum wire (Pt-wire), which worked as an internal electrode. This internal electrode was verified by means of optical microscopy, SEM, and EDS of the Barium Titanate (BaTiO3) ceramic to determine some chemical reaction. The analysis was checked only in BaTiO3 because it is the most common ferroelectric ceramic. Finally, the photovoltaic signal was measured in PLZT with the Pt-wire in a bi-dimensional experimental setup, with a resolution of 50 μm. [ABSTRACT FROM PUBLISHER]

In order to mimic the electrical properties of natural bone, the present work investigated the dielectric, AC conductivity, pyroelectric and piezoelectric properties of HA-40 wt% BaTiO3 (HA-26 vol% BaTiO3) and HA-60 wt% BaTiO3 (HA-44 vol% BaTiO3) composites. Multistage spark plasma sintering was used to achieve the desired combination of properties. The electrical parameters were measured as a function of temperature and frequency. The values of dielectric constant and loss for both the developed composites, measured at room temperature and at 1 KHz frequency was 21, 38 and 0.01 and 0.02, respectively. The AC conductivity for both the composites is found to be of the order of 10−10 and 10−9 (Ωcm)−1, measured under similar conditions. Activation energy calculated from σac vs. temperature plot for HA-40 wt% BaTiO3 is 0.50 eV. The room temperature pyroelectric coefficients for both the compositions are 2.35 and 21 μC/m2K, respectively. The piezoelectric coefficient values (d33) for both the compositions are 0.9 and 1 pC/N, respectively. The observed values of electrical parameters closely resemble with that of the natural human bone. [ABSTRACT FROM PUBLISHER]

A fatigue induced damage zone underneath the electrodes in bulk lead zirconate titanate ceramics has been identified by inspecting the electrical response of the material after removal of the near electrode material. The electrical switching experiments were performed by the application of voltage pulses of different duration in fatigued lead zirconate titanate ceramics. The switching kinetics of polarization have been investigated as a function of switching electric field and fatigue cycle. The experimental results demonstrated that the removal of fatigued zone recovered the switchable polarization and upgraded the switching retardation. The mechanism of the observed phenomena can be explained in terms of the microcraking and charge trapping occurred in the damage zones. [ABSTRACT FROM PUBLISHER]

The relaxation behaviors of barium titanate ceramics were investigated in the temperature range of 200–450°C. The diffuse dielectric anomalies were described by the universal dielectric relaxation law (UDR) and polaron theory. It is indicated the dielectric relaxation of barium titanate at high temperatures is associated with the hopping localized oxygen vacancies. [ABSTRACT FROM PUBLISHER]