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Journal ArticleDOI

A new hole-bridge structure based on a SiO2 nanoarray and its ferromagnetism

05 Apr 2014-Colloids and Surfaces A: Physicochemical and Engineering Aspects (Elsevier)-Vol. 446, pp 151-155
TL;DR: In this article, a SiO 2 nanoarray with a hole-bridge structure was constructed using a modified Stober method, which was obtained through three-dimensional self-organization from a siO 2 aqueous suspension by vertical deposition.
About: This article is published in Colloids and Surfaces A: Physicochemical and Engineering Aspects.The article was published on 2014-04-05. It has received 7 citations till now. The article focuses on the topics: Ferromagnetism.
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Journal ArticleDOI
TL;DR: Overall, the magnetic bentonite-chitosan beads can be used as a highly efficient adsorbent for radioactive waste disposal and management.

120 citations

Journal ArticleDOI
TL;DR: SiO2 amorphous nanopowder (NP) is produced with the specific surface area of 154m2/g by means of evaporation by a pulsed electron beam aimed at Aerosil 90 pyrogenic ammorphous NP (90 m 2/g) as a target as discussed by the authors.
Abstract: SiO2 amorphous nanopowder (NP) is produced with the specific surface area of 154 m2/g by means of evaporation by a pulsed electron beam aimed at Aerosil 90 pyrogenic amorphous NP (90 m2/g) as a target. SiO2 NP nanoparticles showed improved magnetic, thermal, and optical properties in comparison to Aerosil 90 NP. Possible reasons of emergence of d0 ferromagnetism at the room temperature in SiO2 amorphous NP are discussed. Photoluminescent and cathode luminescent properties of the SiO2 NP were investigated.

15 citations


Cites background from "A new hole-bridge structure based o..."

  • ...Messages that silicon [1, 2] and silicon dioxide (SiO 2 ) [3, 4] possess noticeable magnetic properties at room temperature appear now in increasing frequency....

    [...]

Journal ArticleDOI
TL;DR: In this paper, an amorphous SiO2 nanopowder with a specific surface area of 154 m2/g has been prepared using pulsed electron beam evaporation of a target from a pyrogenic amorphized Aerosil 90 nanopowder (90 m 2/g).
Abstract: An amorphous SiO2 nanopowder with a specific surface area of 154 m2/g has been prepared using pulsed electron beam evaporation of a target from a pyrogenic amorphous Aerosil 90 nanopowder (90 m2/g). It has been found that SiO2 nanoparticles exhibit improved magnetic, thermal, and optical properties as compared to the properties of particles of the Aerosil 90 nanopowder. Possible factors responsible for the appearance of ferromagnetism at room temperature in the amorphous SiO2 nanopowder formed upon electron beam evaporation have been discussed. The photoluminescence and cathodoluminescence properties of the SiO2 nanopowder have been investigated.

12 citations

Journal ArticleDOI
TL;DR: In this article, the carbon solubility boundary in the Al2O3 lattice was lower than 1.07 wt % C. The dependence of the form of the cathode-luminescence spectra and the phase compositions of the prepared Al 2O3 and Al3-C nanopowders has been found.
Abstract: Three-phase (corundum + δ phase + amorphous phase) amorphous–nanocrystalline powders of pure and carbon-doped Al2O3 (x C = 1.07–6.6 wt %) have been produced by pulsed electron beam evaporation in vacuum. The corundum hexagonal nanocrystals in the Al2O3–C nanopowder (x C = 1.07 wt %) had sizes about 5 nm. The carbon solubility boundary in the Al2O3 lattice was lower than 1.07 wt % C. The dependence of the form of the cathode-luminescence spectra and the phase compositions of the prepared Al2O3 and Al2O3–C nanopowders has been found. The absence of R lines of Cr3+ ions in photoluminescence spectra of doped nonopowders has been detected. All the nanopowders of the pure and C-doped Al2O3 were ferromagnets at room temperature with the maximum magnetization of ~0.12 emu/g at x C = 6.6 wt %.

3 citations

Journal ArticleDOI
TL;DR: In this paper, a single-layer PS sphere template was immersed in SiO2 precursor solution for a certain period of time, and then the PS nanospheres were removed by high temperature-annealing to form SiO 2 network structure.
Abstract: We use solution immersion method to prepare the SiO2 network structure. A single-layer PS sphere template was immersed in SiO2 precursor solution for a certain period of time. Filter paper was used to absorb the residual liquid, and then the PS nanospheres were removed by high temperature-annealing to form SiO2 network structure. The Si honeycomb structure was formed on the SiO2 network structure by chemical vapor deposition method. The longer growth time caused the smaller sizes of the Si apertures and produced various quantum size effects. When the growth time is 15 min, the thermal conductivity of the sample is the lowest. The heat conduction behavior of the 15 min sample is similar to that of a phonon crystal due to the aperture size of the sample is almost the same as the mean free path of phonons. Scattering at the interface of the isolated honeycomb microstructures also contributed to the low thermal conductivity. The position and number of the reflection peak of the sample can be controlled by the deposition time. The luminescence properties of the samples are greatly influenced by the surface topography.

3 citations


Cites background from "A new hole-bridge structure based o..."

  • ...36 eV originates from structural defects in the Si nanostructure [24]....

    [...]

References
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Journal ArticleDOI
TL;DR: In this article, a system of chemical reactions has been developed which permits the controlled growth of spherical silica particles of uniform size by means of hydrolysis of alkyl silicates and subsequent condensation of silicic acid in alcoholic solutions.

12,884 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of annealing environment on the luminescence characteristics of ZnO thin films that were deposited on SiO2/Si substrates by reactive RF magnetron sputtering were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL).
Abstract: The effects of annealing environment on the luminescence characteristics of ZnO thin films that were deposited on SiO2/Si substrates by reactive RF magnetron sputtering were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). An analysis of the O 1s peak of ZnO film revealed that the concentration of oxygen vacancies increased with the annealing temperature from 600 °C to 900 °C under an ambient atmosphere. The PL results demonstrated that the intensity of green light emission at 523 nm also increased with temperature. Under various annealing atmospheres, the analyses of PL indicated that only one emission peak (523 nm) was obtained, indicating that only one class of defect was responsible for the green luminescence. The green light emission was strongest and the concentration of oxygen vacancies was highest when the ZnO film was annealed in ambient atmosphere at 900 °C. The results in this investigation show that the luminescence mechanism of the emission of green light from a ZnO thin film is associated primarily with oxygen vacancies.

481 citations

Journal ArticleDOI
01 Apr 2002-Langmuir
TL;DR: A simple preparation method of ordered multilayer films of submicrometer and micrometer-sized monodisperse latex particles in the broad range of 0.2-2.5 μm is reported in this article.
Abstract: A simple preparation method of ordered multilayer films of submicrometer- and micrometer-sized monodisperse latex particles in the broad range of 0.2-2.5 μm is reported. The films were prepared from aqueous suspensions byvertical deposition at elevated temperatures. Both hydrophobic polystyrene and hydrophilic core-shell particles allowed good array formation. Three-dimensional lattices were proved by transmission and reflectance vis-NIR-IR spectroscopy. Well-developed Bragg peaks up to 5000 nm have been registered. An observation of Fabry-Perot resonance signals in the spectra also confirms the good array quality. Optical properties of the gratings were investigated by laser diffraction and by diffraction using an optical microscope equipped with a Bertrand lens.

111 citations

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