Particle Size Of BaTiO3 Research Articles

The effect of BaTiO3 on the magnetic behavior of MnZn ferrites at frequencies > 5 MHz

In this article an extensive study is presented on the effect of BaTiO3 on the high frequency performance of MnZn ferrite having a nominal composition Mn0.9Zn0.1Fe2.45O4. It is shown that BaTiO3 at an optimum concentration of 200 ppm wt. is a bulk dopant that dissolves in the spinel lattice leading to microstructures with smaller grain sizes, lower grain boundary resistivities and higher resonance frequencies. Despite an observed increase on the hysteresis losses, the main impact on the magnetic performance is the significant reduction of the high frequency resonance losses. In addition, no dependency has been observed on the particle size of BaTiO3 since nanoparticles produce the same effects as microparticles. Through exploitation of the beneficial effects of BaTiO3, MnZn ferrites with power losses of 195 kW m−3 (5 MHz, 10 mT, 100 °C) or 1125 kW m−3 (10 MHz, 10 mT 100 °C) and a relative initial permeability of 200 could be synthesized. These results belong to the best reported in literature and indicate that the application region of MnZn ferrites can be extended up to application frequencies traditionally dominated by other ferrite material families.

Enhanced Photocatalytic and Anticancer Activity of Zn-Doped BaTiO3 Nanoparticles Prepared through a Green Approach Using Banana Peel Extract

Perovskite barium titanate (BaTiO3) has received a lot of interest due to its extraordinary dielectric and ferroelectric properties, along with its moderate biocompatibility. Here, we investigated how Zn doping tuned the physicochemical characteristics, photocatalytic activity, and anticancer potential of BaTiO3 nanoparticles synthesized from banana peel extract. XRD, TEM, SEM, EDS, XPS, BET, Raman, and PL were utilized to characterize the as-synthesized pure and Zn (1 and 3 mol%)-doped BaTiO3 nanoparticles. All of the synthesized samples showed evidence of the BaTiO3 tetragonal phase, and the XRD patterns of the Zn-doped BaTiO3 nanoparticles showed the presence of a Zn peak. The particle size of BaTiO3 decreased with increasing levels of Zn doping without morphological changes. After Zn doping, the PL intensity of BaTiO3 decreased, suggesting a lower electron–hole recombination rate. BET analysis found that the surface area of Zn-doped BaTiO3 nanoparticles was higher than that of pure BaTiO3. Under visible irradiation, the photocatalytic activity of pure and Zn-doped BaTiO3 nanoparticles was compared, and a remarkable 85% photocatalytic activity of Zn (3%)-doped BaTiO3 nanoparticles was measured. As a result, Zn-doped BaTiO3 nanoparticles are recognized as excellent photocatalysts for degrading organic pollutants. According to cytotoxicity data, Zn (3%)-doped BaTiO3 nanoparticles display four-fold greater anticancer activity against human lung carcinoma (A549) than pure BaTiO3 nanoparticles. It was also observed that Zn-doped BaTiO3 nanoparticles kill cancer cells by increasing the intracellular level of reactive oxygen species. Furthermore, compared to pure BaTiO3, the Zn-doped BaTiO3 nanostructure showed better cytocompatibility in non-cancerous human lung fibroblasts (IMR90). The Zn-doped BaTiO3 nanoparticles have a reduced particle size, increased surface area, and a lower electron–hole recombination rate, which are highly beneficial for enhanced photocatalytic and anticancer activity. Overall, current data showed that green-fabricated Zn-BaTiO3 nanoparticles have superior photocatalytic and anticancer effects along with improved biocompatibility compared to those of pure BaTiO3. This work underlines the significance of utilizing agricultural waste (e.g., fruit peel) for the fabrication of BaTiO3-based nanostructures, which hold great promise for biomedical and environmental applications.

Preparation, structural and dielectric properties of nanocomposite Al2O3/BaTiO3 for multilayer ceramic capacitors applications

Nano-composites ceramic of (Al2O3/BaTiO3) were successfully fabricated by Sol. Gel. technique with a weight ratio of Al2O3: BaTiO3, 1:100 wt%, respectively. X-Ray diffraction (XRD), Infrared (FT-IR), scanning electron microscopy (SEM) and Raman spectroscopy have been used to characterize the fabricated samples. Experimental data revealed that adding of Al2O3 changed both the structure and particle size of BaTiO3 from tetragonal with 7–9 μm to orthorhombic with 400–600 nm for Al2O3/BaTiO3. Moreover, SEM shows uniform grains distribution with nano-sized particles. Raman spectra shows a peak at 900 nm for BaTiO3 and split for Al2O3/BaTiO3. The FT-IR recorded several peaks related to Al2O3/BaTiO3 at low wavenumber <900 cm−1. UV/Vis spectroscopy shows an enormous peak appeared around wavelengths 550–700 nm. Finally, the dielectric properties as functions of temperature and frequency of Al2O3/BaTiO3 investigated and showed a major effect of the nanoparticles of Al2O3. Further, with increasing frequency, the complex dielectric constants of Al2O3/BaTiO3 nanocomposite decreased sharply. This can be explained by Maxwell–Wagner type of polarization in accordance with Koop's theory. The temperature dependence of complex dielectric constant exhibited phase transition of BaTiO3. The dielectric behaviors of the composites have been studied in detail to be used as the Multilayer ceramic capacitors in the electronic equipment.

High Efficiency Water Splitting using Ultrasound Coupled to a BaTiO3 Nanofluid.

To date, a number of studies have reported the use of vibrations coupled to ferroelectric materials for water splitting. However, producing a stable particle suspension for high efficiency and long‐term stability remains a challenge. Here, the first report of the production of a nanofluidic BaTiO3 suspension containing a mixture of cubic and tetragonal phases that splits water under ultrasound is provided. The BaTiO3 particle size reduces from approximately 400 nm to approximately 150 nm during the application of ultrasound and the fine‐scale nature of the particulates leads to the formation of a stable nanofluid consisting of BaTiO3 particles suspended as a nanofluid. Long‐term testing demonstrates repeatable H2 evolution over 4 days with a continuous 24 h period of stable catalysis. A maximum rate of H2 evolution is found to be 270 mmol h–1 g–1 for a loading of 5 mg l–1 of BaTiO3 in 10% MeOH/H2O. This work indicates the potential of harnessing vibrations for water splitting in functional materials and is the first demonstration of exploiting a ferroelectric nanofluid for stable water splitting, which leads to the highest efficiency of piezoelectrically driven water splitting reported to date.

Linear and ferroelectric effects of BaTiO3 particle size on the energy storage performance of composite films with different polymer matrices

The size of ceramic fillers is an important parameter influencing the energy storage performance of composite materials. Herein, composite films containing linear poly (methyl methacrylate) (PMMA) and ferroelectric polyvinylidene fluoride (PVDF) polymer matrices and BaTiO3 (BT) particles with different sizes were fabricated, and the dependences of their dielectric and energy storage properties on BT particle size were investigated systematically. The observed particle size effects on the PMMA/BT and PVDF/BT characteristics were almost identical. In particular, the dielectric permittivities of the composites gradually decreased while their breakdown electric fields (Eb) increased with an increase in BT particle size. Moreover, the composite films with small BT particles exhibited high discharged energy densities (Udischarged) at relatively low electric fields. The Udischarged of the PMMA/BT-60 nm sample was 5.68 J/cm3, which was 1.24 times higher than that of the PMMA/BT-500 nm sample at an electric field of 450 MV/m. Meanwhile, the Udischarged of PVDF/BT-60 nm was 10.06 J/cm3, which was 1.27 times greater than the Udischarged of PVDF/BT-500 nm at 350 MV/m. However, under high electric fields, the composite films with large BT particles produced higher Udischarged values. The maximum Udischarged magnitudes of the PMMA/BT-500 nm and PVDF/BT-500 nm samples were equal to 9.53 J/cm3 at 650 MV/m and 18.12 J/cm3 at 525 MV/m, respectively. Furthermore, the composite films filled with 500 nm BT particles demonstrated high cycling stability and fatigue endurance. The results of numerical simulations conducted to complement the experimental data revealed that the composite films with large BT particles possessed higher breakdown strengths.

Fabrication and characterization of a novel photoactive-based (0\u20133) piezocomposite material with potential as a functional material for additive manufacturing of piezoelectric sensors

The development of 3D-printed sensors and actuators from piezocomposite materials has increased in recent years due to the ease of production, low-cost and improved functionality additive manufacturing provides. The piezocomposite material developed in this work has the potential to be used as a functional material in stereolithographic additive manufacturing by combining the optical, viscoelastic properties of NOA 65 and the piezoelectric properties of Barium Titanate. The new (0–3) piezocomposite material consists of Norland Optical Adhesive 65 (NOA 65) as the polymer matrix and Barium Titanate (BaTiO3) with particles sizes (100 nm, 200 nm and 500 nm) as the dielectric filler. We synthesized thin film samples of the (0–3) piezocomposite with 60% w/w BaTiO3 using solution mixing and spin coating method to produce samples with layer thickness of 100 µm. Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) techniques were used to analyze the microstructure of the piezocomposite to determine the effect of different particles sizes of BaTiO3 on the structural and mechanical properties of the composite. The longitudinal piezoelectric coefficient d33 was also measured using the laser vibrometer technique. Both single point scans and full surface scans were carried out to obtain the average piezoelectric coefficient d33 of the composite material. The results of the SEM confirmed the (0–3) structure of the piezocomposite material with isolated BaTiO3 nanoparticles. It further showed the uniform distribution of the BaTiO3 nanoparticles across each of the samples. FTIR analysis showed that the filler nanoparticles had no effect on the native structure of the polymer matrix. The longitudinal piezoelectric coefficient d33 of the piezocomposite material was observed to increase with increasing BaTiO3 particle sizes, while the indentation modulus of the composite investigated using the method of Oliver and Pharr was observed to decrease with an increase in particle size. Results from the single point scans showed the composite with BaTiO3 particle size 100 nm, 200 nm and 500 nm having an average d33 of 2.1 pm/V, 3.0 pm/V and 3.9 pm/V while the average d33 obtained from the full surface scan of 1430 scan points showed 1.4 pm/V, 6.1 pm/V, 7.2 pm/V.

Stabilization of Size-Controlled BaTiO3 Nanocubes via Precise Solvothermal Crystal Growth and Their Anomalous Surface Compositional Reconstruction.

Crystal growth of barium titanate (BaTiO3) using a wet chemical reaction was investigated at various temperatures. BaTiO3 nanoparticles were obtained at an energy-efficient temperature of 80 °C. However, BaTiO3 nanocubes with a preferred size and shape could be synthesized using a solvothermal method at 200 °C via a reaction involving titanium tetraisopropoxide [(CH3)2CHO]4Ti for nucleation and fine titanium oxide (TiO2) nanoparticles for crystal growth. The BaTiO3 nanocubes showed a high degree of dispersion without the use of dispersants or surfactants. The morphology of BaTiO3 was found to depend on the reaction medium. The size of the BaTiO3 particles obtained using water as the reaction medium was the largest among the particles synthesized using various reaction media. In the case of alcohol reaction media, the BaTiO3 particle size increased in the order methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol. Furthermore, BaTiO3 powder obtained using alcohol reaction media resulted in cubic shapes as opposed to the round shapes obtained when water was used as the medium. We found that the optimal condition for the synthesis of BaTiO3 nanocubes involved the use of 1-butanol as the reaction medium, resulting in an average particle size of 52 nm, which is the average distance of the cubes measured diagonally from corner to corner, and gives an average side length of 37 nm, and a tetragonal crystal system as evidenced by the powder X-ray diffraction pattern obtained using high-energy synchrotron X-rays. The origin of the spontaneous polarization of the BaTiO3 tetragonal crystal structure was clarified by a pair distribution function analysis. In addition, surface reconstruction of BaTiO3 nanocubes led to an outermost surface comprising two layers of Ti columns.

Improvement in Electrical Properties of (Bi0.5Na0.5)TiO3 (BNT) Ceramics Using the Seed-Induced Method

(Bi0.5Na0.5)TiO3 (BNT) lead-free ceramics were prepared by the seed-induced technique using different particle sizes of BaTiO3 (BT) powder as seeds. The BT seeds was synthesized by the molten-salt method and then calcined at different temperatures of 750 (750BTs), 800 (800BTs) and 850 °C (850BTs). The pure perovskite seeds (5 mol%) were mixed with the starting materials of the BNT system for conventional mixed oxide method. After that, the mixture was calcined and sintered at 900 °C for 2 h and 1100 °C for 2 h, respectively. From results it was found that the particle size of BT seed increased with calcine temperature increase from 750 to 850 C. The samples of non-BT seed (S0) and BT seed-added (S1, S2 and S3) showed pure perovskite phase. Average density values were in the range of 5.53-5.77 g/cm3. Dielectric constant (εr) measured at room temperature (at 1 kHz) was in the range of 732.04-788.59. The dielectric loss (tanδ), remnant polarization (Pr) and coercive field (Ec) values decreased with the addition of BT seed. The highest piezoelectric coefficient (d33) ∼156 pC/N was obtained for the sample of 850BTs (S3).

Structure and morphology of yttrium doped barium titanate ceramics for multi-layer capacitor applications

Multilayer ceramic capacitors (MLCCs) are essential components in pulsed power systems (PPS) with high charging and discharging capacity for energy storage applications. Yttrium oxide (Y2O3)–doped barium titanate (BaTiO3) (BTY) ceramics with a chemical formula of 60 BaO + (40-x) TiO2 + x Y2O3 (x = 2, 8 and 15) have been synthesized by usual solid state reaction process. These ceramics are analyzed by XRD, FTIR and SEM techniques. The crystalline nature of the undoped BaTiO3 (BT) and Y2O3 doped ceramics were confirmed by XRD analysis. In addition, a doublet peak at 30.2° has been shifted to lower angles as the concentration of Y3+ ions increases. The functional groups of these BT and BTY2 ceramics were investigated using FTIR analysis. Morphological studies were performed through scanning electron microscopy (SEM), revealing the average particle size of BT 331 nm and BTY2 136 nm from Image-J software.

Electrical Characteristics of Multilayered Ceramic Capacitors Depending on BaTiO3 Particle Size

Multilayer ceramic capacitors were prepared with BaTiO3-based ceramics of different grain sizes (150–500 nm), having appropriate dielectric properties and high-temperature stability. The grain size effect on the dielectric properties and insulation resistivity of fine-grained BaTiO3 ceramics at room temperature and high temperatures under electric fields were investigated. The reduction in particle size has a strong effect on DC-bias characteristics and withstanding voltage characteristics per unit thickness. BaTiO3 ceramic capacitor with smaller grains had higher reliability under the DC bias and higher withstanding voltage per unit thickness due to the shell with para-electricity. The highly accelerated lifetime test showed that the insulation resistance with smaller particle size exhibited one order higher as the voltage increases at higher temperatures and the samples with a size of 500 nm had a sharp drop in insulation resistance at 200 V. Small particles (150, 250 nm) have a smaller product of insulation resistance and capacity than larger particles (500 nm). But, the withstanding voltage per unit thickness of the small particles (150, 250 nm) was 82, 71 V/μm, respectively, which was greater than 58 V/μm of the larger particles (500 nm). This is thought to be an effect of suppressing the movement of defects in the smaller particles because small grains have many grain boundaries.

Controlled hydrothermal synthesis of different sizes of BaTiO3 nano-particles for microwave absorption

Different sizes of barium titanate (BaTiO3) nano-particles were synthesized from precursor H2Ti3O7 nanotubes through facile hydrothermal synthesis by using EtOH/H2O as mixing solvent. Field-emission scanning electron microscopy (FESEM) was mainly used to investigate the effects of solution alkalinity, polarity, and hydrothermal temperature on the size and morphology evolution of BaTiO3 nanoparticles. The results indicate that the presence of strong alkalinity improved the size evenness of BaTiO3 nanoparticles possibly because of the re-dissolution and re-precipitation of TiO32− ions. BaTiO3 nanoparticles with the average diameters of approximately 21 and 53 nm were obtained in 9:1 and 1:1 EtOH/H2O (v/v) hydrothermal medium, respectively. Compared with that, the size of BaTiO3 particles prepared in pure distilled water reached up to ∼512 nm. As for the reason, the addition of EtOH could lower the polarity of hydrothermal medium and make the medium reach the supersaturation more easily, thus limiting the size growth of BaTiO3 particles. In addition, the presence of EtOH led to easier formation of BaTiO3 nanoparticles even at mild hydrothermal temperature, but the particle size was limited even though the temperature was much increased. This is possibly due to lowered interfacial activity in the presence of EtOH. By adjusting solution alkalinity, EtOH/H2O volume ratios, and hydrothermal temperature, BaTiO3 nanoparticles with the average sizes of approximately 21, 53, 104, 284, and 512 nm, were obtained, and more different and controlled nano-sizes can be expected by further hydrothermal adjustment. In the end, microwave absorption evaluation indicated that decreased size of the BaTiO3 particles enhanced the reflection loss. One possible reason is that the decreased nano-size led to the increased specific surface area of the BaTiO3 nanoparticles.

Calcination Effect on Structural Trasformation of Barium Titanite Ferroelectric Ceramic by Sol Gel Method

High purity barium titanate BaTiO3 was successfully synthesized by using the sol-gel technique. Barium acetate Ba(CH3COO)2 and tetrabutyl titanate, Ti(C4H9O)4 was dissolved moderately in the solvent of glacial acetic acid and ethanol was added as the chemical modifier. The synthesized BaTiO3 nanoparticle was calcined at the temperature range of 700 ºC to 1100 ºC. The powders were further characterized by X-ray diffraction and scanning electron microscopy (SEM). Fined BaTiO3 powders result indicates the phase of tetragonal structures and high crystallites of BaTiO3. It was observed that the crystallinity and particle size of BaTiO3 is greatly influenced by the calcination temperature.

Optimization of 3D printing parameters for BaTiO3 piezoelectric ceramics through design of experiments

Paste extrusion is an additive manufacturing technique that deposits paste through a nozzle in a layer-by-layer fashion to form a three-dimensional object. This technique can be used to fabricate piezoelectric ceramics with complex geometries and excellent material properties to fabricate sensors, capacitors, and energy storage devices with a high level of customization. Different factors can affect the quality of piezoelectric ceramics when using the paste extrusion technique, for example, the composition of the paste and printing parameters. This paper presents a study to optimize the piezoelectric coefficient, relative density, dielectric permittivity and dimensional accuracy of BaTiO3 by using design of experiments with a 2k-1 design. Results indicated that the factors having a significant impact on the end-product outputs were the BaTiO3 particle size and the binder concentration on the paste formulation. Using the optimal levels makes it possible to achieve a piezoelectric coefficient higher than 200 pC/N and a density of 90% of the theoretical value of pure BaTiO3.

Effects of the Particle Size of BaTiO₃ Fillers on Fabrication and Dielectric Properties of BaTiO₃/Polymer/Al Films for Capacitor Energy-Storage Application.

BaTiO3/polymer/Al (BPA) composite films for energy storage were fabricated by way of a roll coating and thermal curing process. The coating slurry consisted of silicon-containing heat-resistant resin (CYN-01) and BaTiO3 particles with various particle sizes obtained from commercial BaTiO3 powders processed at different durations of wet sand grinding in the presence of silane coupling agent (KH550), which not only improves the dielectric performance of the BPA films but also facilitates its production in a large scale. The major influence factors, such as the ratio between BaTiO3 and resin and the size of BaTiO3 particles, were investigated and their related mechanisms were discussed. The results show that modifying BaTiO3 particles (D90 = 0.83 μm) with the silane coupling agent of KH550 enhances the dielectric properties of the BPA films. The typical BPA films obtained exhibit a high dielectric constant of 32, a high break strength of 20.8 V/μm and a low dielectric loss of 0.014. The present work provides a simple and convenient way to prepare high-quality ceramic/polymer composite films for energy-storage application in a large scale.

Effect of Particle Sizes of BaTiO&lt;sub&gt;3&lt;/sub&gt; (BT) Seed on Microstructure and Electrical Properties of (Ba&lt;sub&gt;0.85&lt;/sub&gt;Ca&lt;sub&gt;0.15&lt;/sub&gt;)(Zr&lt;sub&gt;0.1&lt;/sub&gt;Ti&lt;sub&gt;0.9&lt;/sub&gt;)O&lt;sub&gt;3&lt;/sub&gt;

The study was conducted to find out the effect of particle sizes of BaTiO3 (BT) seed on the microstructure and electrical properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics. The BT seeds were prepared by the molten salt method. Results indicated that the BT seed powder showed a single pure perovskite phase when using a low temperature of ~750°C. The particle sizes of BT seeds increased from ~381 to ~600 nm with increasing heating temperatures from 750 to 900°C. After that, the different BT seeds were mixed with BaCO3, CaCo3, ZrO2 and TiO3 via the solid state reaction method. The mixed powder was calcined and sintered at 1200 °C for 2 h and 1450 °C for 4 h, respectively. The microstructure, phase formation and electrical properties were investigated. All ceramic samples showed a pure perovskite phase. The density and average grain size values of ceramics were in the range of 5.36-5.47 g/cm3 and 9.83-11.86 μm, respectively. The highest values of dielectric constant (εr), piezoelectric constant (d33) were 3393 and 452 pC/N, respectively which obtained at the sample of BT-seed size 372 nm doped.

Preparation and characterization of nano-sized BaTiO3 particles using aqueous peroxotitanium acid solution: Effects of pH adjustment

Aqueous peroxotitanium acid solution derived from the TiO2 fluorinated using F2 gas was used for the preparation of nano-sized BaTiO3 particles in this study. The prepared aqueous peroxotitanium acid solution having a homogeneous pale yellow-green was very stable even for 1 year. Nano-sized BaTiO3 particles were synthesized under different pH values (3–8) by a reaction between the prepared peroxotitanium acid and the Ba(OH)2 through a co-precipitation method. Depending on pH values, the prepared BaTiO3 particles had two kinds of phases; ferroelectric phase (tetragonal, pH 3–7) and paraelectric phase (cubic, pH 8). Namely, with increasing the pH values, average particle sizes of BaTiO3 were decreased from 300 nm to 40 nm and it affected a dielectric constant of BaTiO3. The dielectric constant (4200) of BaTiO3 with 75 nm prepared using the peroxotitanium acid solution was 3 times higher than that with 300 nm of BaTiO3.

Modeling the Electrical Conduction in Epoxy–BaTiO3 Nanocomposites

Epoxy–BaTiO3 nanocomposites are widely used as the dielectric material in embedded planar capacitors. To maximize the effective dielectric constant of this nanocomposite, the loading of BaTiO3 is kept as high as possible, but at high loadings of BaTiO3 the magnitude of undesirable leakage current in the dielectric also increases. This paper investigates the conduction mechanism in epoxy–BaTiO3 nanocomposites. Further, the effects of BaTiO3 loading and the size of BaTiO3 particles on the electrical conduction are investigated and also modeled. To investigate the conduction mechanism, capacitor structures (Cu/dielectric/Cu) with nanocomposite dielectric were fabricated using the colloidal process. The loading and size of BaTiO3 particles were varied in the nanocomposite dielectric. Once the capacitor structures were fabricated, the leakage current was measured across the capacitor dielectric as a function of temperature and voltage. The leakage current data were checked for any consistency with the standard conduction models using regression analysis, and the dominant conduction mechanism was identified. Finally, the activation energy of the dominant conduction mechanism was trended as a function of BaTiO3 loading and particle size both experimentally and theoretically.

Development of Dielectric Elastomer Actuators - Part II: Preparation of the High Dielectric Constant Film Actuators Containing BaTiO&lt;sub&gt;3&lt;/sub&gt; Particles

Dielectric elastomer actuators with high dielectric constant and flexibility were prepared. These actuators were fabricated by the composite of barium titanate (BaTiO3) and polyester-type thermosetting polyurethane (TSU), which was molecularly-designed to become less hard segment content. In this study, the effects of particle size, volume fraction and manufacturing method of BaTiO3 were investigated. In addition, the mechanically-stretched effect in composites was also evaluated. It turned out that the electrical breakdown strength increased with the increase of particle size of BaTiO3 and in volume fraction as well as the use of BaTiO3 synthesized by the oxalate method. In addition, prestrain of composites also raised the electrical breakdown strength. However, the addition of BaTiO3 to polyurethane didn’t contribute to the actuation under a lower electric field.

Analysis and Characterization of Phase Evolution of Nanosized BaTiO3 Powder Synthesized Through a Chemically Modified Sol-Gel Process

In the current research, a cost-effective and modified method with a high degree of reproducibility was proposed for the preparation of fine nanoscale and high-purity BaTiO3. In contrast to the other established methods, in this research, carbonate-free BaTiO3 nanopowders were prepared at a lower temperature and in a shorter time span. To reach an in-depth understanding of the scientific basis of the proposed process, an in-detail analysis was carried out for characterization of nanoscale BaTiO3 particles via differential thermal analysis (DTA)/thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques aided by theoretical calculations. The effects of the temperature and time of calcination process on the preparation mechanism, phase transformation, tetragonality, and particle size of BaTiO3 were examined. The reaction that results in the formation of barium titanate initiated at approximately 873 K (600 °C) and seemed to be completed at approximately 1073 K (800 °C) and the polymorphic transformation of cubic to tetragonal initiated at approximately 1173 K (900 °C). It seemed to be completed at approximately 1373 K (1100 °C). According to the reaction mechanism, the formation of BaTiO3 in the initial stage of the interfacial reaction between BaCO3 and TiO2 depends on the BaCO3 decomposition. In the second stage, the BaTiO3 formation is controlled by barium diffusion through the barium titanate layer. In this stage, in contrast to the literature, no secondary phase was detected. The overall characterizations showed the temperature is more effective than time on the progress in process of preparation because of its diffusion-controlled nature.

Multiferroic behaviour of nanoporous BaTiO3

Nanoporous BaTiO3 particles with an average diameter of 27 nm have been synthesized using a soft template based on poloxamer. The pore width has been found to be ∼10 nm. The nanoporous particles have a surface area of 107 m2gm−1. This introduces a large surface area leading to the creation of a large number of oxygen vacancies. The latter contributes to the ferromagnetic behavior of the nanoparticles. A multiferroic property was exhibited by these particles. The oxygen vacancy concentration decreased as the BaTiO3 particle size increased. The magnetization decreased with an increase in the particle size. A magnetodielectric parameter of 11% has been observed in this system corresponding to an applied magnetic field of 10 kOe.