Magnetoresistance of La2/3(CaxBa1-x)1/3MnO3/NiO Composite Materials

2005 ◽  
Vol 475-479 ◽  
pp. 897-900
Author(s):  
Shui Yuan Chen ◽  
Zhi Gao Huang ◽  
Heng Lai ◽  
Rongquan Gai ◽  
Feng Ming Zhang ◽  
...  
Keyword(s):  
Composite Materials ◽  
Sol Gel ◽  
Percolation Model ◽  
Experimental Results ◽  
Tunneling Magnetoresistance ◽  
Nio Nanoparticles ◽  
Gel Method ◽  
Three Samples ◽  
Level Model ◽  
Two Level Model

Ferromagnetic (FM) La2/3(Ca0.6Ba0.4)1/3MnO3 and antiferromagnetic (AFM) NiO nanoparticles were synthesized using sol-gel method, respectively. La2/3(Ca0.6Ba0.4)1/3MnO3 (1 mol)/ x NiO (x= 0, 0.05 and 0.15mol) composites with the coated NiO were prepared. The experimental results indicate that, both phases of LCBMO and NiO coexist clearly in the composites and the sizes of the NiO nanoparticles in the intergranular region between the LCBMO particles are very small; the interface of NiO influences evidently the value of MR and it is found that the tunneling MR for x=0.05 is the largest in three samples. The magnetoresistance behavior has been explained by two-level model of tunneling magnetoresistance and percolation model well.

scholarly journals Preparation and Photocatalytic Performance of ZnO/Sepiolite Composite Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chao Li ◽  
Huijuan Li ◽  
Guicheng He ◽  
Zhiwu Lei ◽  
Wenyuan Wu
Keyword(s):  
Composite Materials ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Environmental Pollutants ◽  
Chemical Properties ◽  
Treatment Method ◽  
Blue Dye ◽  
Synthesis Methods ◽  
Gel Method ◽  
Sol Gel Method

Photocatalytic technology is a widely used water treatment method, whose efficiency can be increased by developing a suitable photocatalyst fabrication procedure. In this study, five different synthesis methods were utilised for the preparation of novel ZnO/sepiolite photolytic composites, namely, sol-gel method, hydrothermal reduction, hydrolytic precipitation, powder sintering, and impregnation-reduction. The obtained photocatalysts were characterised by scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The differences between the applied photocatalyst preparation methods and the reasons for these differences were discussed, and the photocatalytic activities of the prepared composite materials were compared. The obtained results revealed that the physical structure, chemical properties, and photocatalytic performance of the composite produced by the sol-gel method were superior to those of the materials fabricated by the other four methods. Moreover, this material also exhibited high photocatalytic stability, while its photocatalytic degradation of methylene blue dye proceeded via a quasi-first-order reaction. The prepared composites have broad application prospects in photocatalysis and can be potentially used for treating environmental pollutants.

Application of Nanometer Metal Oxides in Infrared Ray Shielding Transparent Thin Film

2011 ◽  
Vol 474-476 ◽  
pp. 195-199 ◽  
Author(s):  
Ai Hong Guo ◽  
Xue Jiao Tang ◽  
Su Juan Zhang
Keyword(s):  
Thin Film ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Sol Gel ◽  
Volume Ratio ◽  
Experimental Results ◽  
Mass Ratio ◽  
Gel Method ◽  
Water Based ◽  
Better Than

Water-based infrared ray shielding coating, that is, nanometer metal oxide is added to the water-based paint, which has anti-IR features without affecting the transparency of the paint. In this paper, the nanometer oxides are prepared by sol-gel method, added into polypropylene sour. In order to improve the infrared ray shielding of the thin film, two kinds of nanometer oxides are added into the polypropylene sour with different volume ratios, the shielding performance of the paint is studied. Experimental results show: in the 8000 ~ 4000cm-1 range, the transmittances of infrared ray is 30% to 75%; in 4000 ~ 400cm-1 range, transmittances decrease significantly; 3% ZnO, 3% Fe2O3, 3% Y2O3, 2% Al2O3 are the best mass ratio of every single nanometer oxide; the infrared shielding rate of Fe2O3 and Y2O3 mixture with the volume ratio of 1 to 4 is better than Fe2O3 and Y2O3 single.

Fabrication of Bi-2223 Powders Using Sol-Gel Method

2011 ◽  
Vol 412 ◽  
pp. 125-128 ◽  
Author(s):  
Ming Ya Li ◽  
Xiao Yan Wang ◽  
Cheng Li Ye ◽  
Feng Lin Xue
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Chelating Agent ◽  
Experimental Results ◽  
Main Phase ◽  
Gel Method ◽  
Sol Gel Method ◽  
Dwelling Time ◽  
Metal Nitrates ◽  
Gel Technique

The Bi-2223 powders were fabricated by the sol-gel technique. Metal nitrates were used as starting materials, and ethylenediamineteracetic acid was used as chelating agent. The solution was heated until it turns to gel. Then the organic was removed at a temperature of 240°C, and the nitrite was removed at 500°C. The powder was calcined at different temperature, varying the dwelling time. Experimental results show that the main phase of samples after heat treatment is Bi-2212 phase.

Nonstoichiometry and Point Defect Structure of Olivines, (FexMg1-x)2SiO4

1994 ◽  
Vol 369 ◽  
Author(s):  
Tse-Lun Tsai ◽  
R. Dieckmann
Keyword(s):  
Transition Metal ◽  
Point Defect ◽  
Noble Metal ◽  
Defect Structure ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Experimental Results ◽  
Cationic Composition ◽  
Gel Method ◽  
Point Defect Structure

AbstractA thermogravimetric study was conducted on synthetic olivines (FexMg1-x)2SiO4' prepared either by a conventional ceramic methodor a sol-gel method, to determine the nonstoichiometry and the point defect structure. Measurements were carried out as a function of oxygen activity and cationic composition at elevated temperatures. To avoid the dissolution of transition metal components of the silicate into noble metal containers, commonly used in previous investigations, quartz containers were used. The analysis of the point defect structure of olivines based on the new experimental results is presented.

STUDIES ON THE TiO2 THIN FILMS DOPED WITH Fe3+

2005 ◽  
Vol 19 (01n03) ◽  
pp. 671-673
Author(s):  
PENG XIAO ◽  
WANLU WANG
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Electrical Properties ◽  
Sol Gel ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
Gel Method ◽  
X Ray ◽  
Nanometer Particles

The Fe 3+- TiO 2 thin films obtained through sol-gel method were characterized by x-ray diffraction, AFM and Raman spectroscopy. It was found that TiO 2 films consisted of nanometer particles. The experimental results shows that the nanometer TiO 2 thin films doped with Fe 3+ were greatly improved in the activity aspect. This may be ascribed to change their structure and electrical properties after doping with Fe 3+. The results were discussed theoretically in detail.

Analysis of Linear and Nonlinear Optical Properties of NiO Nanoparticles by Sol–Gel Method

2018 ◽  
Vol 17 (05) ◽  
pp. 1850003 ◽  
Author(s):  
V. Usha ◽  
R. Vettumperumal ◽  
S. Kalyanaraman ◽  
R. Thangavel
Keyword(s):  
Nonlinear Optical ◽  
Sol Gel ◽  
Spectroscopic Techniques ◽  
Face Centered Cubic ◽  
Nio Nanoparticles ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Optical Susceptibility ◽  
Linear And Nonlinear

Nanocrystalline nickel oxide (NiO) were prepared by low cost sol–gel method and analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectra (EDX), Raman, photoluminescence (PL) and UV-Vis-NIR spectroscopic techniques. XRD spectrum confirmed the face centered cubic structure of NiO nanoparticles and it showed polycrystalline nature without any impurity. Magnetic ordered phase related modes of NiO nanoparticles was observed from Raman spectra, which also confirmed the absence of secondary phases in NiO nanoparticles. Linear and nonlinear refractive index and optical susceptibility of NiO nanoparticles were calculated and discussed using Tauc’s method and Wemple and DiDomenico single oscillator model. Calculated maximum value of third ordered nonlinear optical susceptibility ([Formula: see text] is [Formula: see text] revealed that the NiO nanoparticles were suitable in nonlinear optical devices applications. Simulation of second harmonic efficiency, spectral band width and quasi phase matching of NiO nanocrystals are discussed using optiFDTD.

NiO nanoparticles prepared by the sol-gel method for a dye sensitized solar cell applications

2018 ◽  
Vol 1 (92) ◽  
pp. 15-21
Author(s):  
M. Szindler ◽  
M.M Szindler ◽  
L.A. Dobrzański ◽  
T. Jung
Keyword(s):  
Solar Cell ◽  
Nickel Oxide ◽  
Sol Gel ◽  
Dye Sensitized Solar Cell ◽  
Nio Nanoparticles ◽  
Nickel Oxide Nanoparticles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Dye Sensitized ◽  
Harvesting Efficiency

Purpose: The purpose of this article is to synthesized NiO nanostructures by sol-gel method and characterized them for use in dye sensitized solar cells. For this purpose, a paste prepared from nanoparticles was prepared and screen printed on a glass substrate with the FTO layer. Design/methodology/approach: Nickel oxide nanoparticles was synthesized with participation of nickel (II) nitrate hexahydrate and citric acid. The prepared nanopowder has been subjected to structural analysis using a transmission electron microscope (TEM). Scanning Electron Microscopic (SEM) images were taken with a Zeiss Supra 35. Qualitative studies of chemical composition were also performed using the Energy Dispersive Spectrometer (EDS). The structure of nickel oxide was investigated by X-ray crystallography. An average crystallite size were calculated using Scherrer method and Williamson-Hall analysis. Light harvesting efficiency LHE was calculated from measured absorbance. Findings: The uniform nickel oxide nanoparticles with spherical shape were successfully produced by sol-gel method. The diameter of the as prepared nanoparticles does not exceed 25 nm which is confirmed by the XRD and TEM analysis. The light harvesting efficiency of the electrode in the entire studied range it’s over 90%. Therefore the NiO can be an attractive alternative to the most commonly used TiO2. Research limitations/implications: The next step in the research will be to investigate the ZnO/NiO composite on the properties of the photoelectrode of dye sensitized solar cell. Practical implications: The unique properties of produced NiO nanostructural materials have caused their interest in such fields as medicine, transparent electronics and photovoltaics. Originality/value: The NiO nanoparticles were prepared using sol-gel method and then effectively used in the photoanode of dye sensitized solar cell.

scholarly journals Tunneling Magnetoresistance in a Two-Layered La2-2xCa1+2xMn2O7Polycrystal

1999 ◽  
Vol 54 (12) ◽  
pp. 695-698
Author(s):  
Tie-Jun Zhou ◽  
Z. Yu ◽  
Y. W. Du
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Tunneling Magnetoresistance ◽  
Gel Method ◽  
Sol Gel Method ◽  
Low Field

Abstract By the sol-gel method, a polycrystal bulk of two-layered La2-2xCa1+2xMn2O7 with x = 0.2 was successfully synthesized. A high sensitive low-field TMR was found at low temperature.

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