Barium Strontium Titanate: Comparison of Material Properties Obtained via Solid-State and Sol–Gel Synthesis

Microwave dielectric properties of the system Ba 1− xSr xTiO 3

Plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) has been successfully employed for the deposition of (100) oriented barium strontium titanate (BST) thin films on a variety of substrate and electrode materials. The incorporation of O2 plasma, which was used as oxidation reactant, has helped to reduce the required temperature for deposition of high-quality STO and BST thin films. This low temperature processing may make it possible to integrate BST on Si and GaAs. BST films with low leakage current densities of about 10−7 A/cm2 at 2-volt (about 105 V/cm) operation were obtained from PE-MOCVD processing. Moreover, the BST results of capacitance-temperature (C-T) measurements show that most of the PE-MOCVD BST films have Curie temperatures of about 30–35°C and a peak dielectric constant of 600–800 at zero bias voltage, The sharp transition in the C-T data indicates that the BST films may have a high induced pyroelectric coefficient at room temperature, which is highly desirable for uncooled IR imaging arrays. The x-ray diffraction and Rutherford backscattering spectrometry results show that the BST film composition reproducibility was well controlled at around Ba0.75Sr0.25TiO3 with a 4% variation. Device quality BST thin films with the thickness of 1000–2000 Å were produced. These results indicate that PE-MOCVD has high potential to be further developed and promoted as a production deposition technique providing high permittivity dielectric thin films for microelectronics and IR sensor industries.

In this paper the influence of barium strontium titanate (BST) xerogel as a sinter additive and BaCu(B$_{2}$O$_{5}$) (BCB) as a liquid phase sintering aid on the sintering behavior of BST bulk ceramics is investigated. BST as well as BCB powders were synthesized via a mixed oxide route and BST gel via a sol-gel process. Compared to pure BST bulk ceramics, BST gel reduces the sintering start (onset temperature) by up to 174°C and increases the density for a sintering temperature of 1200°C. By adding BCB to the BST powder the sintering was completed much faster and the onset temperatures were reduced by 281°C and 312°C for 1 mol. % and 2.5 mol. %, respectively. With 2.5 mol. % BCB, the highest density of 96 % (5.41 g∙cm$^{-3}$) was achieved at 950°C.

The powders of lead-free material namely (nonhazardous) barium strontium titanate (BST) with different stoichiometric compositions have been synthesized by the sol–gel method. Ba[Formula: see text]Sr[Formula: see text]TiO3 (BST) materials possess the properties of both ferroelectric and dielectric materials. These materials have spontaneous polarization that can be reversed by an applied electric field and they remain polarized even when the applied external electric field is removed. Synthesized samples have been subjected to structural, morphological, and dielectric characterizations. In this study, BST nanopowders with different substitutions of [Formula: see text] (where [Formula: see text]= 0.2, 0.3, 0.4, 0.5, and 0.6) were prepared by the sol–gel method, which is an easy method with low power consumption and low temperature requirement and produces higher yield. Nanopowders had average particle sizes of 12–24 nm and particles sizes after sintering at 1000[Formula: see text]C for 3 h were 197, 267, 79.80, 63.09, and 63 nm. All resulting pellets had a polycrystalline structure. Crystal structure, space group, morphological characterization, and particle size were determined from the structural analysis using X-ray powder diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM). The dielectric measurements were made for BST pellets under different frequencies (1–200 kHz) from room temperature to 250[Formula: see text]C. The dielectric constants for the bulk were 743, 1566, 1091, 766, and 626 for [Formula: see text]= 0.2, 0.3, 0.4, 0.5, and 0.6, respectively. From dielectric measurements, samples with [Formula: see text]= 0.2 and 0.3 had the Curie temperatures of 70[Formula: see text]C and 28.5[Formula: see text]C, respectively, and remained intact below 0[Formula: see text]C. The sample with [Formula: see text]= 0.3 had a good dielectric measurement and moderate dissipation factor; it may be used in capacitance application as energy stores.

Comparison of structural and dielectric properties of doped (M, R and A) barium strontium Titanate: Review

Nanofibers of barium strontium titanate (BST) by sol–gel processing and electrospinning

Microstructural, morphological and dielectric properties of Mo, Se co-doped Ba0.6Sr0.4TiO3 perovskites

Sol–gel derived nanocrystalline and mesoporous barium strontium titanate prepared at room temperature

Preparation and dielectric properties of barium strontium titanate glass-ceramics sintered from sol–gel-derived powders

Investigation of Barium Strontium Titanate (Ba0.95Sr0.05TiO3) synthesized via conventional solid-state reaction and co-precipitation route with diverse sintering temperatures

ABSTRACTComplex Sol-Gel Process (CSGP) was applied to the preparation of LiNi0.5Co0.5O2. Starting sol-solutions were prepared in two different ways: I, in which aqueous ammonia was added to a starting solution of Li+-Ni2+-Co2+ acetate-ascorbate, and II in which LiOH was added to a solution of Ni2+- Co2+ and NH4+ acetate-ascorbate. It was found that in the absence of ascorbic acid, or at its lower content (≤0.2 M on 1M σ Li+- Ni2+- Co2+) precipitation of Ni hydroxides occurred. Regular sols were concentrated ∼3 times, gelled and dried at 140°C. Intensive foaming was observed for samples during further heating. Consequently for scaling up to 200g in a run a preliminary long drying procedure followed by self-ignition step (∼400°C) was introduced. Thermal transformation of the gel to solid was studied by TG, DTA, XRD and IR. The main feature of this step is carbonate formation. The final structure LiNi0.5Co0.5O2 is observed after heating for Ih at 800°C. For larger scale production the extension of firing time was necessary. Electrochemical properties of the LiNi0.5Co0.5O2 compound, prepared by the CSGP were evaluated and considered satisfactory.

Lead iron phosphate glasses are potentially useful for nuclear waste immobilization, and others applications. Lead iron phosphate glass powders were obtained from a mixture of NH 4 H 2 PO 4 , PbO and Fe 2 O 3 melted in an induction furnace and fast cooled. After milling, the material was pressed in a die and finally sintered. The particle size distribution, specific surface area, density values and crystalline phases were determined. Three amorphous halos were observed with intensities depending on the particle size distribution, These halos were assigned to be from ferric metaphosphate (Fe(PO 3 ) 3 , lead orthophosphate Pb 3 (PO 4 ) 2 and lead metaphosphate Pb(PO 3 ) 2 compounds. It is proposed that ferric metaphosphate is the main compound on the surface of the particles and lead orthophosphate and lead metaphosphate are in the inner part of the particles. The milling process allows to exhibit these compounds which are then detected by the X-rays diffraction. Pre-sintered pellets were exposed to CsCl aqueous solution and the absorption of Cs has been determined by SEM. Crystallization temperatures were determined by thermal analyses, and it is noted that the maximum is displaced from 534 to 543°C for samples containing CsCl. The surface area was determined to be 29 cm 2 /g after milling.

Dielectric properties and phase transitions of La2O3- and Sb2O3-doped barium strontium titanate ceramics

This effort aimed to investigate the differences between raw materials and thin films to enhance the film performance and get encouraging results. Barium strontium titanate (BST) is a solid solution consisting of titanate barium (BT) and titanate strontium (ST). BST powder was synthesized using the sol–gel process, and BST film was deposited using pulsed laser deposition (PLD). Barium, strontium acetate, and Ti-isopropoxide were utilized as raw material sources. XRD was used to characterize the BST perovskite crystal structure. The SEM and LCR meters revealed morphology surface and dielectric properties. XRD pattern shows a cubic structure phase. The particle size of the bulk exhibited 122.88[Formula: see text]nm while the film particle size was 84[Formula: see text]nm. The dielectric constant of the bulk shape exhibited was greater than the form of the films, which was attributed to different thicknesses, densities, defects, and porosity.

Electrets and piezoelectric materials hold immense promise for enhancing bone regeneration strategies. Barium titanate and its solid solutions hold significant potential for bone regeneration strategies. However, addressing the challenges related to biocompatibility, optimization, and manufacturing is essential before the possible clinical applications. This study focuses on barium strontium titanate (BST)‐hydroxyapatite (HA) scaffolds as a potential bone growth enhancer. Ba0.5Sr0.5TiO3 is prepared by mixing the barium titanate and strontium titanate commercial nano powders and HA is synthesized using the sol–gel method, and BST‐xHA composite samples are fabricated using conventional solid‐state method. The samples are sintered at 1200–1300 °C, and the phase structure, microstructure, density, and electrical and mechanical properties are evaluated. Biological assessments, including MTT tests, are conducted. The electrical properties of composite samples improve, and the one with 20 wt% HA shows the highest amount of fracture toughness. Importantly, MTT assay results confirm the nontoxic nature of the BST‐HA composite samples with the best OD value in BST‐40 HA composite sample, making it a promising candidate for bone regeneration applications.