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Enhancing both electrical and mechanical properties of active or passive polymers using piezoelectric nanofillers is an attractive option to develop new multifunctional materials, which are usually lead-free piezoelectric materials and can replace traditional PZT-based ones. These novel materials are also lightweight and flexible. In this paper, an eco-friendly nanocomposite piezoelectric plate in a bimorph arrangement with the potential application of an energy harvester is suggested. The natural frequencies of these bimorph plates are investigated using a developed meshless solution with MLS shape functions. The bimorph nanocomposite plate is made of two lead-free piezoelectric materials including Polyvinylidene Fluoride (PVDF) as a polymeric matrix and Barium Titanate (BaTiO3) nano-powder as the nano-scale reinforcement. Material properties of the resulting piezoelectric nanocomposite are approximated using Eshelby's approach. The electromechanical governing eigenfrequency equations of such cantilever and bridge-type energy harvesters are developed by employing a five-independent third-order shear deformation theory (TDST). The effects of plates' geometrical dimension and nanofiller amount on the natural frequencies of both types of the proposed energy harvesters are investigated. [ABSTRACT FROM AUTHOR]

The Barium Zirconium Titanate and Barium calcium Titanate (BZT-BCT) is lead free substitute for making piezoelectric material and capacitive material used in oscillator, Sensors and capacitor. In this paper we have made BZT- BCT using solid state reaction route. And the chemicals used are BaCO3, ZrO2, TiO2 and CaCO3 in proper quantity. All the prerequisite chemicals are properly mixed in Mortar Pestle with eathanol for fourty five minutes. Then it is heated for 4 hours in Muffle furnace at 1300 degree celcius. After cooling again it is heated 1400 degree celcius for two hours. Now the BZT-BCT is prepared. After this we did the characterization with XRD and SEM which shows proper result. Again this chemical is treated with 5% citric Acid(soft chemical) at low temperature (around 100 degree celcius)by steam bath. As a result Change in crystalline size in nanometer is obsorbed. For the characterization of soft chemical treated BZT- BCT, it is again observe with PL, FTIR, XRD. All show the proper result. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is a common air pollutant that can also be used to diagnose kidney disease. Therefore, the development of ammonia gas sensors is critical for health protection. This paper presents a simple method for fabricating an NH3 gas sensor that employs perovskite barium titanate (BaTiO3) as the active sensor material grown on a p-Si (100) silicon substrate. Barium titanate (BaTiO3) based thick films without (Pristine) and with lithium doping (Li-doped) were prepared by Chemical Solution Deposition (CSD) method and deposited on p-Si (100) substrate by spin coating. To study the structure properties of the resulting films, X-ray diffraction (XRD) characterization. These samples were made into gas sensors and tested under various conditions. At room temperature, the Li-doped film has a 44% higher responsivity for 100 ppm of NH3 than the undoped BaTiO3-based gas sensor. [ABSTRACT FROM AUTHOR]

In this growing world, development is accompanied by ever-increasing energy demand and storage. Capacitors are the most useful and promising devices for energy storage. In this paper, we compare the performance of TiO2, BaTiO3, and their composites as dielectrics for capacitor application. For this purpose, we fabricated, analyzed, and compared the single oxide ceramics and their composite forms, which are made by adding 10%, 20%, and 30% of BaTiO3 to TiO2. The structural analysis was done via x-ray diffraction, and to procure the I-V (current-voltage) plots and C-V (capacitance-voltage) (at 10 kHz), hysteresis inquisition has been carried out and utilized. From the result, it is concluded that TiO2 and BaTiO3 and their composites possess high dielectric constants and have good interface quality with leakage current density, of which 30%BaTiO3/TiO2 composite possesses the most desirable values. The study unveils the increased dielectric property of the BaTiO2/TiO2 composite and adds a new member to the dielectric capacitor family in the energy-storing field. [ABSTRACT FROM AUTHOR]

In this paper, the electronic and optical properties of nickel doped Barium titanate (BTO) nanostructures are presented using Density functional theory (DFT). The plane-wave-based density functional theory (DFT) calculations are performed using the Quantumwise ATK ver 11.8.2 with local-density approximation (LDA) and generalized gradient approximation (GGA) for both undoped and nickel doped Barium titanate nanostrucrures. The calculated band gap energies and optical spectra for the nickel doped Barium titanate nanostructures are compared with the undoped samples of the same. It is found that, the band gap energies of undoped barium titanate calculated by LDA and GGA varies from 4.6 eV to 5 eV. However, the band gap calculated for doped Barium titanate is found to be 0 eV for both LDA and GGA approximations. It is therefore, observed that the doping of Nickel results in a decrease in band gap energy of materials. [ABSTRACT FROM AUTHOR]

In this paper we report the method of synthesis of ferroelectric polymer Polyvinyldene fluoride (PVDF) and Barium Titanate (BaTiO3) composite self supporting thin films and its dielectric response. BaTiO3 was synthesized by solid state reaction method. The PVDF – BaTiO3 polymer composites with various concentrations were synthesized by solution mixing method using Dimethylformadide (DMF) as a solvent. The phase transformation and surface methodology of the prepared composites were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) respectively. The XRD pattern confirms the formation of tetragonal pervoskite structure of ferroelectric phase. The XRD pattern shows the proper mixing of BaTiO3 particles intestinally and found to be improving its crystallinity with increase of BaTiO3 composition in the PVDF matrix. The dielectric properties of the composites as a function of frequency were computed using impedance analyzer. The dielectric constant decreases with increase of frequency shows the Maxwell – Wagner type of interfacial polarization in accordance with Koop’s phenomenological theory. [ABSTRACT FROM AUTHOR]

The aim of this paper, is to test new ways in order to improve the lifespan of electrical machines fed by PWM inverters. The tested method consists in increasing the turn-to-turn capacitance in order to reduce the electrical stress applied to the turn-to-turn insulation. The difficulty is to keep this stress under the partial discharge inception voltage (PDIV). The proposed paper focuses its investigations on the nature of mineral charges and their ratios (5 vol%, 10 vol%, 20 vol%) in impregnation varnishes used to build motor windings. With such solutions, it is possible to obtain a significant reduction of the turn-to-turn stress. The research work consists in performing capacitance measurements on elementary twisted specimens made with various diameters (0.5mm, 0.85mm, 1.25mm) of enameled wires and several varnishes charged with alumina or barium titanate at micro-scale. [ABSTRACT FROM PUBLISHER]

Rare earth doped Barium Titanate (BaTiO3) were studied due to high permittivity, excellent electrical properties and have wide usage in various applications. This paper reviewed on the electrical properties of RE doped BaTiO3 (RE: Lanthanum (La), Erbium (Er), Samarium (Sm), Neodymium (Nd), Cerium (Ce)), processing method, phase transition occurred and solid solution range for complete study. Most of the RE doped BaTiO3 downshifted the Curie temperature (TC). Transition temperature also known as Curie temperature, TC where the ceramics had a transition from ferroelectric to a paraelectric phase. In this review, the dielectric constant of La-doped BaTiO3, Er-doped BaTiO3, Sm-doped BaTiO3, Nd-doped BaTiO3 and Ce-doped BaTiO3 had been proved to increase and the transition temperature or also known as TC also lowered down to room temperature as for all the RE doped BaTiO3 except for Er-doped BaTiO3. [ABSTRACT FROM AUTHOR]

This paper reports the particle and crystallite size characterizations of mechanically alloyed Ba(1-x)SrxTiO3 (BST) with x = 0.3 and 0.7 prepared with the assistance of a high-power sonicator. Analytical grade BaCO3, TiO2 and SrCO3 precursors with a purity of greater than 99 wt.% were mixed and milled using a planetary ball mill to a powder weight ratio of 10:1. Powders obtained after 20 hours of milling time were then sintered at 1200°C for 4 hours to form crystalline powders. These powders were further treated ultrasonically under a fixed 6.7 gr/l particle concentration in demineralized water for 1, 3, 5, 7 hours and a fixed ultrasonic irradiation time of 1 hour to the dispersion of 6.7; 20; 33.3 gr/l concentrations. As to the results of crystallite size characterization, it is demonstrated that the mean crystallite size of BST with x = 0.3 and 0.7 undergo a slight change after the first 1 hour irradiation time and then remain almost unchanged. This was in contrary to the particle size in which the mean particle size of BST with x = 0.3 increased from 765 nm to 1405 nm after 7 hours irradiation time, while that of x = 0.7 increased from 505 nm to 1298 nm after 3 hours and then reduced back to the initial size after 7 hours ultra sonication time. The increase in particle size was due to large of cohesive forces among fine particles. It is also demonstrated that the concentration of particles in a dispersion with anionic surfactant do not effective to reduce the particle sizes ultrasonically. Nanoparticles with the mean size respectively 40 and 10 times larger than their respective crystallite size were successfully obtained respectively in x = 0.3 and x = 0.7. [ABSTRACT FROM AUTHOR]

The Barium Titanate is a very well known dielectric ceramic belongs to perovskite structure. It has very wide applications in the field of electronic, electro ceramic, electromechanical and electro-optical applications. Barium Titanate has very high dielectric constant as well as low dielectric loss. Substituted dielectrics are one of the most important technological compounds in modern electro ceramics. Its electrical properties can be tuned flexibly by a simple substitution technique. This has encouraged researchers to select a typical cation to be substituted at cationic sites. In the present paper, the review of various synthesis methods of Barium Titanate compound with the effect of different dopants, the grain size on the dielectric properties at various temperatures is discussed. [ABSTRACT FROM AUTHOR]

Lead-free ceramic material Barium Zirconium Titanate (BaZr0.10Ti0.90O3 or BZT) and composite of Ga2O3/BZT were prepared via hydrothermal method. The crystal structure, lattice microstrain, lattice parameters, and the formation of BZT and Ga2O3/BZT nanostructures were investigated by XRD analysis. The microstructure, grain size measurement and elemental analysis were carried out by SEM and EDX. XRD analysis show the pure and crystalline phase of the prepared samples. To determine the crystallite size, various calculations methods like Scherrer, Williamson-Hall and Size-Strain graphs were constructed with the help of XRD patterns. SEM images demonstrated the change in the micro-morphology of the pristine BZT after the addition of Ga2O3 whereas EDX results are in good agreement with the stoichiometric ratio of the prepared samples. [ABSTRACT FROM AUTHOR]

The in-plane ferroelectric characteristics of amorphous Barium Titanate (BTO) thin films are investigated using parallel silver (Ag) electrodes. The BTO thin films and Ag electrodes are deposited by RF and DC sputtering method. A novel wire mask method is followed to separate the Ag electrodes in parallel. Chemical structure and microstructure of the BTO thin films are explored by using X-ray photoelectron spectroscopy, Atomic force and Scanning electron microscopies. Characteristic ferroelectric switching is recorded with saturated polarization × area product values of 5 µC. Furthermore, changes in the local microstructure of the BTO is correlated to the origin of spontaneous polarization [ABSTRACT FROM AUTHOR]

The magnetic and electric properties of Ni- BaTiO3- Polydimethylsiloxane (PDMS) composite has been investigated. Any system with spin-charge coupling at room temperature is expected to be useful for device applications. Nickel is a room temperature ferromagnet, and barium titanate is a room temperature ferroelectric material, which makes the system as a magnetoelectric. The polymer PDMS was used to make the flexible magnetoelectric material. It is observed that the saturation magnetization is reduced by the presence of polymer, and coercivity is not much lowered. Also, the effect of filler loading on the magnetic and electric properties is studied. [ABSTRACT FROM AUTHOR]

In the present work, the structural and optical properties of Ba1-xSmxTiO3(x=0.0& 0.05) bulk ceramics have been reported. The barium titanate (BaTiO3) has tetragonal perovskite structure with geometry ABO3.Solid state reaction method was used to synthesize the bulk ceramics. These synthesized bulk ceramics were characterized by x-ray diffraction (XRD), ferroelectric and UV-vis spectroscopy. The XRD results understandably showed thesingle-phase crystalline nature of all the samples and declined the presence of any secondary phase. The band gap of BaTiO3 and Sm doped BaTiO3 was found to be 2.42 eV and 3.02 eV. It increases with increasing the doping concentration. P-E hysteresis loops have estimatedthe value of remnant polarization =0.3849µC/cm² and coercive field=-1.5718 kV/cm for BaTiO3 and remnant polarization =0.4783µC/cm² and coercive field=-1.4193 kV/cm for Sm doped BTO [ABSTRACT FROM AUTHOR]

The composites with composition of (1-x)BaTiO3(BTO) – (x)NiFe2O4(NF) with x=0.25 and 0.75 were synthesized by sintering the mixtures of highly ferroelectric and highly magnetostructive magnetic phaseobtained by auto combustion method. Structural study using Reitveld refinement of X-ray diffraction (XRD) pattern indicated a tetragonal structure (space group P4mm) for BTO phase while to that NF compound crystallizes in cubic structure (space group Fd3m). XRD pattern show that BTO and NF phase exists independently in NiFe2O4 doped composites without the presence of undesirable phases. The energy band gap (Eg) of both the composites have been measured using Diffuse Reflectance Spectroscopy (DRS). Band gaps are found to be 3.13 eV and 2.75 respectively for x=0.25 and 0.75. With the increase of NF ferrite phase, band gap is found to decrease. This is due to the fact that band gap value of the Nickel Ferriteis less as compared to Barium Titanate. This indicate the possibility of easy manipulation of the band gap over a range of energies by mere control of the molar ratio of phases. The electrical study of these materials were investigated using ferroelectric (P-E) loop tracer. For x=0.25 composite has shown better electrical property in comparison to other investigated composite for x=0.75. Remnant polarization and coercive field decreased with the increase of the content of magnetic phase. [ABSTRACT FROM AUTHOR]

We demonstrate the effect of parallel and antiparallel orientations of spontaneous and piezoelectric polarizations upon the I-V characteristics of vertical metal/GaN/AlGaN/GaN heterostructures. Unlike in the generally accepted model considering parallel orientation of piezoelectric and spontaneous polarization, we achieved reasonable agreement between simulations and experiment only on assuming antiparallel orientation of the two kinds of polarization. [ABSTRACT FROM AUTHOR]

The bulk Sm doped BaTiO3 ceramics have been prepared using solid state reaction method. The prepared bulk ceramics have been characterized using x-ray diffraction and dielectric measurements. X-ray diffraction results show the single-phase nature of Sm doped BaTiO3 ceramics. Dielectric properties of the Sm doped BaTiO3 ceramics have been measured as a function of frequency room temperatures. It is observed that dielectric constant increases initially with Sm doping, and then start decreasing with further increasing in Sm doping. Dielectric constant of all the samples show dispersion behavior. It is observed that at lower value of frequency the dielectric constant decreases rapidly and becomes frequency independent at higher value of the frequency. It is found that the dielectric loss decreases with frequency for app the composition, however for pure and 3% Sm doped BaTiO3, dielectric loss increases initially up to 500 kHz and then decrease with further increases in frequency and becomes independent at higher frequency. [ABSTRACT FROM AUTHOR]

In this work 0-3 connectivity composites based on poly(vinylidene fluoride) (PVDF) and containing 30 vol% of BaTiO3 nanoparticles were prepared by using two different processing methods: solvent casting and melt blending. In both cases, the ensuing composite materials were compression molded to obtain sheets suitable for the subsequent characterization. In order to induce the formation of the electro-active β polymorph of PVDF, the compression molding conditions were properly adjusted. A thorough characterization was then performed to investigate the influence of processing conditions on the dielectric properties of the composites, taking into account PVDF polymorphism and particles dispersion within the polymer matrix. Experimental evidences suggest that dielectric characteristics of the composites are strongly affected by the processing procedure; in particular, composites from melt blending with high amounts of β phase have higher permittivity values compared to those obtained from solvent casting, probably due to a synergistic contribution of PVDF polymorphism and morphological features. [ABSTRACT FROM AUTHOR]

Barium titanate (BaTiO3) is a perovskite crystal structure and it is well known to have many potential applications in microelectronic industry due to its high capabilities to enhance the performance of the capacitors and other energy storage devices. BaTiO3 has been reported to have a wide band gap around 3.4 eV from previous experimental studies. In theoretical studies, the analysis of the band structure of perovskite type of materials still under investigation due to high disagreement with the experimental result. The objective of this research is to investigate the band gap of the tetragonal BaTiO3 calculated using generalized gradient approximation (GGA) and hybrid functional (HSE03) with various pseudopotential methods performed by CASTEP module. The calculation using GGA show underestimation of energy band gap. However, the band gap calculated using HSE03 approximation shows an agreement with the experimental result. [ABSTRACT FROM AUTHOR]

In the current work, we investigated the structural and dielectric properties of Lanthanum oxide (La2O3) doped Barium Titanate (BaTiO3) ceramics and established a correlation between them. Solid state sintering method was used to dope BaTiO3 with 0.3, 0.5 and 0.7 mole% La2O3 under different sintering parameters. The raw materials used were La2O3 nano powder of ~80nm grain size and 99.995% purity and BaTiO3 nano powder of 100nm grain size and 99.99% purity. Grain size distribution and morphology of fracture surface of sintered pellets were examined by Field Emission Scanning Electron Microscope and X-Ray Diffraction analysis was conducted to confirm the formation of desired crystal structure. The research result reveal that grain size and electrical properties of BaTiO3 ceramic significantly enhanced for small amount of doping (up to 0.5 mole% La2O3) and then decreased with increasing doping concentration. Desired grain growth (0.80-1.3µm) and high densification (<90% theoretical density) were found by proper combination of temperature, sintering parameters and doping concentration. We found the resultant stable value of dielectric constant was 10000-12000 at 100-300 Hz in the temperature range of 30°-50° C for 0.5 mole% La2O3 with corresponding shift of curie temperature around 30° C. So overall this research showed that proper La3+ concentration can control the grain size, increase density, lower curie temperature and hence significantly improve the electrical properties of BaTiO3 ceramics. [ABSTRACT FROM AUTHOR]

A series of multiferroic (BiFeO3)1-x(BaTiO3)x [x= 0, 0.1, 0.2, 0.3] ceramics were prepared to study the effect of combine substitution of BaTiO3 in (BiFeO3)1-x(BaTiO3)x. X-ray diffraction studies revealed phase transition from rhombohedral R3c to cubic on substitution of BaTiO3. XRD patterns of (BiFeO3)1-x(BaTiO3)x [BF-BT] has been analyzed and single phase of rhombohedral was found up to 70 mol% of BiFeO3. Morphotropic phase boundary was found just above x=0.3, and finally it transformed into a cubic structure. The BF-BT ceramics exhibited symmetric magnetic hysteresis loops, indicating that they are magnetically ordered materials. Calculated values of remnant magnetizations of samples for x=0.1 and 0.2 indicated weak ferromagnetism in the samples. [ABSTRACT FROM AUTHOR]

Present works based on the performance of the composite films of Barium Titanate (BaTiO3) with Titanium Dioxide (TiO2) and Poly (methyl methacrylate) (PMMA) prepared by simple solution casting technique. Different wt. % compositions of BaTiO3 have been selected to find out the best optimized condition for further investigations. The structural properties have been carried out at room temperature using X-ray crystallography (XRD). The average crystallite size of the BaTiO3 particles in the composite films has been found to be lies in between ∼ 20 -70 nm. It has been found that the peak intensities increase with increasing the wt. % of BaTiO3 in the composite films at room temperature (RT). The XRD analysis revealed that the addition of TiO2 has played a crucial role to enhance the crystalline nature of the composite films at room temperature. Efforts have been made to correlate the results with investigated XRD results of pure BaTiO3 and its composites as observed by other workers at room temperature. [ABSTRACT FROM AUTHOR]

In order to accurately examine structures surfaces, it is interesting to use surface SAW (Surface Acoustic Wave). Such waves are well suited for example to detect early emerging cracks or to test the quality of a coating. In addition, when coatings are thin or when emergent cracks are precocious, it is necessary to excite surface waves beyond 10MHz. Finally, when structures are not flat, it makes sense to have flexible or conformable sensors for their characterization. To address this problem, we propose to develop SAW type of interdigital sensors (or IDT for InterDigital Transducer), based on flexible piezoelectric plates. Initially, in order to optimize these sensors, we modeled the behavior of these sensors and identified the optimum characteristic sizes. In particular, the thickness of the piezoelectric plate and the width of the interdigital electrodes have been studied. Secondly, we made composites based on barium titanate foams in order to have flexible piezoelectric plates and to carry out thereafter sensors. Then, we studied several techniques in order to optimize the interdigitated electrodes deposition on this type of material. One of the difficulties concerns the fineness of these electrodes because the ratio between the length (typically several millimeters) and the width (a few tens of micrometers) of electrodes is very high. Finally, mechanical, electrical and acoustical characterizations of the sensors deposited on aluminum substrates were able to show the quality of our achievement. [ABSTRACT FROM AUTHOR]

In this work, ternary bulk systems based on polyvinylidene fluoride (PVDF), synthesised barium titanate (BaTiO3, BT) nanopowder and multi walled carbon nanotubes (MWCNTs) were fabricated by film stacking technique, starting from solvent cast films. The main purpose was to investigate the influence of BT and MWCNTs addition to the polymeric matrix on its microstructural and dielectrical properties. In order to achieve it, different BT concentrations, ranging between the 60 and 75%wt, were tested, whereas a MWCNTs content of 2%wt was maintained constant. The morphology was studied by observation at scanning electron microscopy (SEM), the microstructure and crystalline phases investigated by X-Ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy, and the electromagnetic properties measured in the microwave region (8-12 GHz). The electromagnetic response of the investigated bulk systems was also simulated as function of the sample thickness. [ABSTRACT FROM AUTHOR]

A theoretical model for the nonlinear thermo-magneto-electric coupling in laminates was established. The laminates were made of giant magnetostrictive materials and piezoelectric materials. The predictions fit the experimental results qualitatively and quantitatively. This model then was adopted to predict the influences of the temperature, interface coupling factor and different piezoelectric materials on magnetoelectric(ME) coupling. It showed that: the laminates, which were made of lead magnesium niobate-lead titanate (PMN-PT), had better tempeature stability and larger ME coupling among than the laminates which composed of lead zirconate titanate (PZT) and barium titanate (BTO); the laminates had the strongest ME effect at 0 °C; an appropriate interface coupling factor could contribute to lowering the ME effect attenuation caused by temperature variations. This model could provide theoretical basis for the preparation and application of ME devices under different temperature conditions. [ABSTRACT FROM AUTHOR]

In this study, BaTiO3 ceramics have been prepared via solid-state reaction method. The powders were calcined for 2 hours at different temperatures ranging from 600°C to 1200°C. Using X-ray diffraction with a Rietveld analysis, the phase formation and crystal structure of the BaTiO3 powders were studied. Change in crystallite size and tetragonality as a function of calcination temperature were also discussed. It has been found that the formation of pure perovskite phase of BaTiO3 began at calcination condition of 1000 °C for 2 hours. The crystal structure of BaTiO3 formed is in the tetragonal structure. The second phases of BaCO3 and TiO2 existed with calcination temperature below 1000 °C. Purity, crystallite size and tetragonality of BaTiO3 powders were found to increase with increasing calcination temperature. [ABSTRACT FROM AUTHOR]

The aim of the present work is to study how the volume (lattice parameters) changes of barium titanate, induced by a phase transition, which occurs by temperature sweeps, influence magnetic behavior of cobalt ferrite in their composites via inverse magnetostrictive (Villari) effect. Structure, phase composition, and magnetic properties were investigated using X-ray diffraction, Mo¨ssbauer spectroscopy, and temperature dependence of magnetization. The tetragonal-to-orthorhombic phase transition in barium titanate occurring at ∼280 K on cooling can be observed in the zero-field cooled magnetization curve. The other phase transitions, i.e., tetragonal-to-cubic transition at ∼390 K and orthorhombic-to-rhombohedral transition at ∼178 K, were detected neither by magnetic nor by Mo¨ssbauer measurements. [ABSTRACT FROM AUTHOR]

Barium titanate/Polyvinylidene fluoride (BaTiO3/PVDF) nanocomposite thin films were fabricated by sol-gel processing technique. The structural and surface morphological properties have been investigated by using x-ray diffraction and Atomic force microscopy techniques. The optical properties were investigated by studying the transmittance and absorbance spectra take by UV-Visible Spectrophotometer. The effect of annealing temperature on the structural and optical properties are reported and analyzed in the light of reported results in the literature. [ABSTRACT FROM AUTHOR]

Polycrystalline ceramic samples of Ca-doped fresnoite compounds of formula Ba2-XCaXTiSi2O8 (X = 0.0, 0.4, 0.8 & 1.0) have been prepared by conventional solid state reaction method at high temperatures using high purity oxides and carbonates. The formation of the single phase compounds and their structural parameters as well as morphological studies were investigated by X-ray diffraction followed by Rietveld refinement and scanning electron microscopic techniques. The interatomic distances between the atoms for all the compounds were also calculated. The Modulated Differential Scanning Calorimetry (MDSC) has been used to investigate the effect of substitution on the heat capacity, heat flow and other thermal parameters of the compounds. The results are discussed in detail. [ABSTRACT FROM AUTHOR]

We have carried out photoemission experiments to obtain valence band spectra of various crystallographic symmetries of BaTiO3 system which arise as a function of temperature. We also present results of a detailed first principle study of these symmetries of BaTiO3 using generalized gradient approximation for the exchange-correlation potential. Here we present theoretical results of density of states obtained from DFT based simulations to compare with the experimental valence band spectra. Further, we also perform calculations using post density functional approaches like GGA + U method as well as non-local hybrid exchange-correlation potentials like PBE0, B3LYP, HSE in order to understand the extent of effect of correlation on band gaps of different available crystallographic symmetries (5 in number) of BaTiO3 . [ABSTRACT FROM AUTHOR]