Study The Effect of Substitution Ag on behavior of The High Temperature of YBa2Cu3-xAgxO6.5+δ Superconductor

This study reports the effect of Lu addition on the microstructural and superconducting properties of YBa2LuxCu3O7−δ (Y123) superconducting samples with x = 0, 0.1, 0.3, 0.5 and 0.7 by means of X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), electron dispersive X-ray (EDX), electrical resistivity and transport critical current density (Jc) measurements. The samples prepared by the liquid ammonium nitrate and derivatives are exposed to various annealing time (20, 40 and 60 h) and temperature (950, 960 and 970 °C), and the best ambient for the sample fabrication is determined to be 970 °C for 20 h. Zero resistivity transition temperatures (Tc), critical current densities (Jc), variation of transition temperatures, hole-carrier concentration, grain size, lattice parameter, surface morphology, element distribution, crystallinity and resistivity (at room temperature) values of the bulk superconducting samples prepared at 970 °C for 20 h are compared with each other. Tc and Jc values of the samples are inferred from the dc resistivity and the critical current measurements, respectively. The results show that the Tc value of the pure sample is about 90.6 K while the sample doped with 0.1 wt% Lu has the maximum Tc value (92.5 K). However, beyond x = 0.1, the Tc value is observed to decrease toward to 83.5 K with increment in the Lu addition. Similarly, the Jc values measured are found to reduce from 142 to 76 A/cm2 with the addition. Moreover, XRD measurements show that both pure and Lu-doped samples exhibit the polycrystalline superconducting phase with the changing intensity of diffraction lines and contain Y123 and Y211 phase, confirming the incorporation of Lu atoms into the crystalline structure of the samples studied. At the same time, comparing of the XRD patterns of samples, the intensity ratio of the characteristic (110) and (013) peaks on the sample doped with 0.1 wt% Lu is more than that on the other samples prepared. Additionally, SEM images display that the sample doped with 0.1 wt% Lu obtains the best crystallinity, grain connectivity and largest grain size whereas the worst surface morphology is observed for the maximum doped sample (x = 0.7). Further, EDX results demonstrate that the Lu atoms doped are successfully introduced into the microstructure of the Y123 samples studied and the maximum Cu element level is observed for the sample doped with 0.1 wt%, explaining that why this sample obtains the best superconducting properties compared to others. According to all the results obtained, it is concluded that the 0.1 wt% Lu addition into the Y123 system improves the microstructural and superconducting properties of the samples studied.

This study reports the effect of annealing time (15 min, 1.5 and 3 h) and temperature (850, 860 and 870 °C) on the structural and superconducting properties of thin films by means of scanning electron microscopy (SEM), X-Ray analysis (XRD), electron dispersive X-Ray (EDX), resistivity and transport critical current density (Jc) measurements. Zero resistivity transition temperatures (Tc) of the films produced are estimated from the dc resistivity measurements. In addition, the phase and lattice parameters are determined from XRD patterns when the microstructure, surface morphology and element composition analyses of the samples are investigated by SEM and EDX measurements, respectively. The results indicate that Tc values of the films obtained are observed to be in a range of 23–102 K. The Tc of the film annealed at 870 °C for 3 h is found to be the smallest (23 K) while the film annealed at 860 °C for 3 h is noted to obtain the maximum Tc value (102 K). On the other hand, the maximum (minimum) Jc is found to be about 2068 A/cm2 (20 A/cm2) for the film annealed at 860 °C for 3 h (870 for 3 h). Moreover, according to the refinement of cell parameters done by considering the structural modulation, the greatest Bi-2223 phase fraction is noticed to belong to the film annealed at 860 °C for 3 h. Furthermore, SEM measurements show that the best surface morphology, largest grain size and grain connectivity are observed for that film. Based on these results, Tc and Jc values of the samples studied are found to depend strongly on the microstructure. As for EDX results, the elements used for the preparation of samples are observed to distribute homogeneously. The aim of this study is not only to investigate the changes of structural and superconducting properties of the films produced in the varied time and temperature but also to determine the best ambient for the film fabrication and show the feasibility of obtaining Bi-2223 film with tailored structure.

A series of ceramic superconductor compounds with the composition LaxY1-x Ba2Cu3O7-δ are prepared by solid state reaction from the principle routs like La2O3, BaCO3 and CuO with high purity 99.99%. Different measurement is made to show the improvement in high phase superconductor such as resistivity measurement and the X-ray diffraction (XRD). When (x=0.20 and 0.80; x=0.40 and 0.60) an orthorhombic phase is appeared with lattice constants (a= 3.844 Å, b=3.912 Å, c=11.839 Å) and (a= 3.871 Å, b=3.881 Å, c=11.748Å), respectively. This emphasizes the formation of a high temperature superconducting phase. At x=0.5 a phase is changed to a tetragonal where the superconductivity is lost. From the resistivity measurement, the highest (Tc) value is found equals to (97K) for (x=0.20 and x=0.80) comparable with the YBCO-compound which does not normally exhibited Tc-value greater than (95K). The increase in Tc-value may be attributed to the amount of (La) and / or the oxygen content in the mixture which both influence the properties of the compound and are essential for the superconductivity phase.

In order to obtain dense PbNb2O6‐based piezoelectric ceramics with a single orthorhombic ferroelectric phase, Ba, and excess Ti were doped into PbNb2O6 ceramics with the composition of Pb0.92Ba0.08Nb2O6–0.25 wt% TiO2 via a conventional solid‐state reaction method. The ceramics were sintered at 1210°–1300°C. The effects of sintering temperature on the crystallite structure, microstructure, and dielectric and piezoelectric properties were studied in detail. All ceramics had shown a high relative density (>94%) and a single orthorhombic phase. The lattice parameters, grain size, and shape varied with changing sintering temperature. All ceramics exhibited a typical characteristic in ferroelectrics with normal paraelectric–ferroelectric phase transition at the Curie temperature. With increasing sintering temperature from 1210° to 1300°C, the Curie temperature decreased from 554° to 523°C, while the maximum dielectric constant increased. The change in dielectric properties with changing sintering temperature is associated with a competing effect among internal stress, porosity, and grain size. The ceramic sintered at 1260°C possesses an excellent piezoelectric constant (d33=82 pC/N), low mechanical quality factor (Qm=20.52), low dielectric loss (tan δ=0.0062), and high Curie temperature (Tc=535°C), presenting a high potential to be used in high‐temperature applications as piezoelectric transducers.

Photoluminescence and thermoluminescence properties of Pr3 + doped ZnTa2O6 phosphor

We synthesized the YBa m Cu 1+m O y superconductors; m = 2, 3, 4, 5 that were Y123 ( YBa 2 Cu 3 O 7-x), Y134 ( YBa 3 Cu 4 O 9-x), Y145 ( YBa 4 Cu 5 O 11-x), Y156 ( YBa 5 Cu 6 O 13-x), by solid state reaction with the Y 2 O 3, BaCO 3 and CuO as the beginning materials. The calcination temperature was 950°C and varied the sintering temperature to be 950°C and 980°C. The resistivity measurement by four-point-probe technique showed that the Tconset of Y123, Y134, Y145, Y156 were at 97, 93, 91, 85 K, respectively. The XRD and Rietveld full-profile analysis method were used and found that the crystal structure was in the orthorhombic with Pmmm space group with the ratio c/a were 3.0, 4.0, 5.0 and 6.0 for Y123, Y134, Y145 and Y156, respectively. The oxygen content was characterized by Iodometric titration. The ( Cu 3+/ Cu 2+ and Oxygen content) were (0.28, 6.83), (0.19, 8.81), (0.13, 10.79), (0.16, 12.92) of Y123, Y134, Y145, Y156, respectively. We also found that the increasing of sintering temperature has reduced the oxygen content and the critical temperature of all samples.

Recently, Prussian blue analogues (PBAs) have been reported to exhibit a low voltage charge/discharge behavior with high capacity (300–545 mAh/g) in lithium-ion secondary batteries (LIBs) [...]

La1-xSrxMnO3 (x = 0.1, 0.2, and 0.3) nanoparticles (LSMO NPs) were successfully synthesized by a simple sonochemical-assisted method. The prepared samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The compositions of samples were determined by energy-dispersive spectroscopy (EDS) analysis. The temperature dependence of the resistivity of samples was measured using four-probe technique, and the magnetic measurement was performed in a Magnetic Property Measurement System (MPMS XL 7.0). SEM, TEM, and XRD show that LSMO NPs are 40∼80 nm in diameter with a very clean surface, and exhibit single phase perovskite structure. The ferromagnetic transition temperature (Tc) and metal-insulator transition temperature (Tp) of the NPs increase with the doping level x. The maximum values of Tc (377 K) and Tp (264 K) occur at x = 0.3. In this work, the effect of strontium doping level on electrical transport and magnetic properties was systematically studied.

Since the conventional solid state reactions are very slow process around room temperature, the most of inorganic phosphor materials have been synthesized by the high temperature solid state reaction method. The high temperature reaction leads to irregular particle morphology of phosphors. Therefore, the solution synthesis methods such as the co-precupitation, hydrothermal and sol-gel method will become even more important. However, some liquid phase reactions required to dry the solvent and special equipment for the separations. Recently, we reported novel soft chemical synthesis method, water assisted low temperature solid state reaction (WASSR) method[1,2]. This process is very simple and can synthesize the ceramic materials just by mixing of raw materials added a small amount of water. For example, RbVO3 and YVO4phosphors can be synthesized at room temperature just by mixing the raw materials with a small amount of water.In this study, we presents the luminescence properties of nano-phosphors prepared by our original WASSR processing and also discussed the reaction mechanism of WASSR method. For the synthesis of YVO4 using the WASSR method, a stoichiometric ratio mixture of Y2O3 (0.2769 g) (C. I. Kasei Co., Ltd. 3N) and V2O5 (0.2231 g) (Kojundo Chemical Laboratory Co., Ltd. 4N) was mixed using a mortar. A small amount of de-ionized water was added to the mixture in a ratio of 11.4 mol% (approximately 0.05 g), and mixed using mortar for 3 h to synthesize to a single phase. Standard YVO4was also synthesized by the conventional solid-state reaction method for comparison. This reference sample was calcined at 1473 K for 10 h in air. Powder X-ray diffraction (XRD) data were obtained using an X-ray diffractometer (MX-Labo, Mac Science Ltd.). The particle morphologies were observed by a scanning electron microscope (SEM, JSM-5310MVB, JEOL Ltd.). The emission and excitation spectra were measured at room temperature with a spectrofluorometer (JASCO Corp. FP-6500/6600). The particle size of the YVO4 sample prepared by the WASSR method was clearly smaller than that of the sample prepared by the conventional solid-state reaction method. The average particle sizes were approximately under 100 nm for the sample synthesized by the WASSR method and few micrometers size for the sample synthesized by the conventional solid-state reaction method, respectively. Internal quantum efficiency of (Y0.90Eu0.10)VO4 phosphor sample synthesized by WASSR method was 32 % under 300 nm excitation. This value is relatively high value for the conventional nano YVO4:Eu3+phosphors. The samples mixed or heated in the absence of the water are the mixture of raw materials Y2O3 and V2O5. No diffraction peaks of YVO4 phase are present in the XRD patterns. The solubility of the Y2O3 and V2O5 raw materials in water are 0.018 g/Ɩ and 0.700 g/Ɩ, respectively. Total amount of dissolved raw materials in water is negligible low in the reaction of the WASSR method. This result suggests that the reaction is also different from a solution reaction, which occurs by the dissolution of the raw materials. In addition, the WASSR method proceeds without strong mechanical load. Therefore, the reaction mechanism of WASSR method is not a mechano-chemical reaction. In addition, we can be successfully synthesized numerous ceramic materials, such as SrMoO4, BaTiO3, LaPO4:Ce3+,Tb3+, SrAl2O4, Ba2SiO4 and NaEuMo2O8 at low temperature by the WASSR method. Our proposed low cost and low temperature synthesis technique is promising for an industrial application for ceramic materials synthesis processing. [1] KANEKO, T., KIM, S. W., TODA, A., UEMATSU, K., ISHIGAKI, T., TODA, K., SATO, M., KOIDE, J., TODA, M., KUDO, Y., MASAKI. T. & YOON, D. H., 2015. Synthesis of YVO4 nano particles by novel room temperature synthesis method. Science of Advanced Materials, 7, 1502-1505.[2] TODA, K., KIM, S. W., HASEGAWA, T., WATANABE, M., KANEKO, T., TODA, A., ITADANI, A., SATO, M., UEMATSU, K., ISHIGAKI, T., KOIDE, J., TODA, M., KUDO, Y., MASAKI. T. & YOON, D. H., 2016. Novel Soft Chemical Synthesis Methods of Ceramic Materials. Key Engineering Materials, 690, 268-271.

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

Eggshell is bioceramic material that produces by avian that commonly contains of 94 % calcium carbonate, 1 % magnesium carbonate, 1 % calcium phosphate, and 4 % other organic element. This study proposed to investigate the synthesis and characterization of avian eggshell powders. The avian eggshell that used in this study involved chicken, duck, and quail eggshells. The characterization of avian eggshell nanopowder for reducing their grain size from micro to nano involved ball milling process (solid state reaction) with the variation of milling times (3, 5, and 7 hours) and sintering temperature at 1000 oC for 2 hours. X-Ray Diffraction (XRD) test presented the phase characterization of quail eggshell nanopowder which ball-milled for 7 hours, obtained the smallest crystallite size at 19.2 nm. Scanning Electron Microscopy (SEM) test presented the morphological analysis that showed changes in grain size and shape of each variety of the avian eggshell such as spherical, oval, wormlike, cubical, triangular, and some irregular grains. Energy Dispersive X-Ray (EDX) test presented the compound in avian eggshell powders that showed Ca and O level were the highest, while C was the lowest level. Fourier Transform Infrared (FTIR) test presented the possibility of the functional group of the avian eggshell powders that showed Ca-O, Ca=O groups, CaCO3, asymmetric C-O, -CO3, amide, C=O, -OH, alkyl CH, and C-H. While compressibility shown the increase along with the decrease of crystallite and particles size in cubical grain. The highest compression ratio is 67.75 % for chicken eggshell nano powder with 5 hours milling time at 2000 kgf of compression loading

This study deals with the effect of Mn addition on the structural and superconducting properties of Bi1.8Pb0.4Sr2MnxCa2.2Cu3.0Oy ceramics with x=0,0.03,0.06,0.15,0.3 and 0.6 by means of X-ray analysis (XRD), scanning electron microscopy (SEM), electron dispersive X-ray (EDX), resistivity, and transport critical current density (Jc) measurements. Zero-resistivity transition temperatures (Tc) of the samples produced via the standard solid-state reaction method are estimated from the dc resistivity measurements. Moreover, the phase fraction and lattice parameters are determined from XRD measurements while the microstructure, surface morphology and element composition analyses of the samples are investigated by SEM and EDX measurements, respectively. It is found that Tc values are obtained to decrease from 109 K to 85 K; likewise, Jc values are observed to reduce from 3200 A/cm2 to 125 A/cm2 with increasing Mn addition. According to the refinement of cell parameters done by considering the structural modulation, the Mn addition is confirmed by both an increase of the lattice parameter a and a decrease of the cell parameter c of the samples in comparison with that of the pure sample (Mn0). SEM measurements show that not only the surface morphology and grain connectivity are seen to degrade but the grain sizes of the samples are found to decrease with the increase of the Mn addition as well. The EDX results reveal that the elements used for the preparation of samples distribute homogeneously and the Mn atoms enter into the crystal structure by replacing Sr and Cu atoms. The possible reasons for the obtained degradation in microstructural and superconducting properties are also interpreted.

X-ray diffraction, iodometric titration, resistivity and SQUID magnetometry measurements have been performed on samples of YSrBaCu2.6Fe0.4O6+z in which yttrium has been partially replaced by calcium. The calcium-free compound is semiconducting but superconductivity is restored for x>0.05. The normal-state resistivity decreases and Tc increases with increasing Ca concentration. The effective valence of copper decreases with increasing calcium content and there is also some loss of oxygen. The observed behaviour is quite similar to that previously reported for samples which were doped with Al but values of Tc are generally lower with Fe doping. This is thought to be due primarily to the fact that the Fe partially occupies the Cu(2) sites in the superconducting Cu-O planes.

Preparation, infrared emissivity and thermochromic properties of Co doped ZnO by solid state reaction

Two systems of Tl-based copper oxides with a Tl-O monolayer structure, TlBa2Y1−xCaxCu2O7 (1212 phase) and TlBa1+x La1−xCuO5 (1201 phase), have been synthesized. For x = 0, where formal Cu valences in both systems were estimated to be just +2, samples exhibited semiconductive or insulating behaviors in the resistivity measurement. With increasing x, electrical properties of samples became more metallic and superconductivity appeared. For the 1201 phase, the maximum Tc value was about 40K at around x = 0.2, and sample became a metallic nonsuperconductor for x> =0.4. For the 1212 phase, maximum Tc value was about 90K at around x = 0.8 and metallic nonsuperconductivity was not observed.