Papers by Keyword: SrTiO₃

Abstract: Yttrium (Y) modified strontium titanate (SrTiO₃) powders with initial concentration of Y in the range of 0 to 15 mol% were produced through sol-gel technique. X-ray diffraction (XRD) studies show that all the prepared compounds have a perovskite cubic structure with the space group (Pm3m). The lattice constant, lattice strain and crystallite size of the as-prepared samples were estimated from the XRD pattern which reveals the incorporation of Y into SrTiO₃ system, moreover to investigate the quality of the prepared SrYT ceramics powder, the scanning electron microscopy (SEM) was used to determined investigate the morphology, grain size and its distribution. The analysis of the thermal conductivity measurements performed on the obtained powders revealed the effect of the combination of temperature and Y content on the thermal conductivity value, Indeed, the minimum thermal conductivity was 4.12 W/(mK) obtained with 15%Y at 464 K.

Abstract: We have grown a SrTiO₃ thin film from strontium acetate and titanium isopropoxide using chemical solution deposition (CSD) method using a spin coater, and furnace annealed with a temperature of 850°C for 8 hours. We have assessed the thin-film frequency, magnetic field, and electric charges using LCR meter and light intensities of 0 (dark), 4000, 8000, 12000 lux. From the data of LCR meter, it can be measured and see the relationship between the current and the angular velocity will be decreased. Also, the results of the measurements obtained the relationship between magnetic fields and angular velocity is reduced as well. Therefore, we can be assumed the higher the intensity of light shall lower the magnetic properties.

Abstract: The development of energy storage devices encourages the sustainability of research on basic materials of supercapacitor technology. SrTiO₃ is one of metal oxide called as titanate alkali metal ATiO₃ (A = Ba, Sr, Ca). This material shows an excellent dielectric constant, thus expected to be potential as raw material of supercapacitor. In this work, boron was used as a dopant on the SrTiO₃ system to modify its local structure and enhance the electrical properties. Synthesis SrTi_1-xB_xO₃ was carried out using a solid-state reaction method followed by the sintering process in various molar ratio. The microstructure of SrTi_1-xB_xO₃ compound was identified by X-ray Diffraction with Cu-Kα. XRD pattern identified the presence of SrTi_1-xB_xO₃ phase with a slight change in the lattice parameters. I-V measurement confirmed that the electrical conductivity increased gradually up to 16.04 Ω^-1cm^-1. For investigating their application for electrode materials, CV was employed and it presents that the specific capacitance and energy density of x = 0.08 were 5.488 Fg^-1 and 0.110 Jg^-1.

Abstract: In this paper, sample of Eu-doped SrTiO₃ was synthesized using hydrothermal method, in which the Eu (NO₃)₃ and Sr (OH)₂ were as the Eu and Sr source. X-ray diffraction (XRD), scanning electron microscope (SEM) were used to characterize the structure and ingredient of the as-prepared samples. The results show that high-purity of SrTiO₃ was prepared and structure of SrTiO₃ without change with Eu doping. Also, performance of cathodic protection of stainless steel was tested in the photoelectricity cell. Furthermore, the mechanism of the improvement by the rare earth was also detected.

Abstract: Thermoelectric properties of SrTiO₃ doped with 8%Pm at Sr site were investigated using density functional theory and generalized gradient approximation. The transport properties were calculated based on BoltzTraP code at temperature range 300-1200K. In electronic properties study Fermi level were shifted to conduction band region due to high contribution 4f orbital in Pm. Present study thermoelectric figure of merit ZT result was 0.395 at 300K and 0.638 at 1200K. This shows a considerably good value of ZT for SrTiO₃ as n-type oxide. Compared to previous work, ZT were at the range of 0.21 - 0.37 for temperature of 300-1000K in Pr, La, Ta and Ho.

Abstract: In this paper, we investigated the nitrogen oxides (NO, NO₂) detection capability of strontium titanate (SrTiO₃) when used as sensing layer on gas sensitive silicon carbide field effect transistors (SiC-FETs). Sensitivity, selectivity and response times for NO, NO₂, and NH₃ were characterized, to determine the possibility for diesel exhaust after treatment control applications. It was found that NO_x can be detected down to single digit ppm levels at sensor temperatures in the 550°C - 600°C range. In addition, the results indicate that it is possible to suppress sensitivity to ammonia by selecting an operating temperature around 530°C.

Abstract: This study aimed to explore a new perovskite-based color pigment system. The Cr:SrTiO₃ pigments were in the 350 nm range. A solid solution could be obtained at high calcination temperatures as confirmed by both structural and optical characterization. A secondary phase of SrCr₂O₇ was detected at high Cr doping, suggesting a possible complicated nature of Cr species techniques. Shifting of the absorption edge toward the visible range was also observed. The pigments were found to be evenly distributed in the glaze. The synthesized pigment powders were initially brown-maroon and gradually changed to the red and yellow tones when incorporating with the glaze.

Abstract: Cr and La-codoped SrTiO₃ nanoparticles were successfully prepared by a microwave-assisted hydrothermal synthesis. The products were characterized by XRD, TEM, BET specific surface area, and UV-Vis absorption spectra. The photocatalytic activity was determined by deNO_x ability under irradiation of a 450 W high-pressure mercury lamp. The products could absorb the visible light and showed high photocatalytic ability for the decomposition of NO_x gas. All samples showed the photocatalytic activities superior to that of commercial titania (Degussa P25) in both UV and visible light regions.

Abstract: The theoretical method of predicating second and third order elastic constants of cubic and tetragonal material are presented by using first-principles total-energy method combined with the means of homogeneous deformation. The predicted results of SrTiO₃ provide reasonable agreement with the reported experimental data, other theoretical results and Cauchy relations. Since high order elastic constants are very difficult to be measured, the methods presented here provide a valuable guidance for experiments and the investigation of high order elastic properties for cubic and tetragonal materials.

Abstract: Barium titanate (BaTiO₃) / Strontium titanate (SrTiO₃) accumulation ceramics with necking structure of SrTiO₃ nanocubes were prepared using a solvothermal method. XRD measurements confirmed SrTiO₃ and BaTiO₃ with a perovskite structure. The XRD peak intensities of the BaTiO₃ increased significantly as the solvothermal reaction was repeated. After heat treatment of the SrTiO₃ at 900°C, the particles grew larger and formed necked contacts with each other. As the solvothermal reaction was repeated in order to coat with BaTiO₃, the density increased, the porosity decreased, and the thickness of the BaTiO₃ layer increased.