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Bian L.,Chinese Academy of Sciences | Xu J.-B.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Song M.-X.,South University of Science and Technology of China | Dong H.-L.,Miami University Ohio | Dong F.-Q.,South University of Science and Technology of China
RSC Advances | Year: 2013

To observe the high-temperature ferro-electricity at room-temperature, we used a halogen to create a 2p-hole for improving O-Fe p-d electronic transition, and calculated the systematic variations in electronic and magnetic properties using first-principle calculation. The systems prefer to charge disproportionate as Fe3+-O2--Fe2+ with the highly localized halogen concentration increasing, where the O-site halogen creates a 2p-hole to disproportionate Fe charge from Fe3+-d5 orbital with a full-filled triple degeneracy orbits (t2g) orbital to Fe 2+-d5-d0 with a partially filled t2g orbital. Whatever at room-temperature or high-temperature phase, the halogen substitutes, typically, for F (or Cl)-doping, induce the electrons to transfer from O-2p4 → unoccupied Fe3+-3d5 to O-2p4→Bi3+-6p3, while the ferromagnetic (FM)-anti-ferromagnetic (AFM) phase transits at about 1 atom per cell. Furthermore, to retain O-Fe electron transfer process, we applied the crystallographic anisotropy to produce the strong Fe-O orbital hybridization which offsets the effect of 2p-hole, and it causes more significant O-2p 4 → unoccupied Fe3+-d5 electronic transitions at the valence band. This study opens a new perspective to the development of multiferroic devices with independent temperature. This journal is © The Royal Society of Chemistry. Source


Wang L.,CAS Xinjiang Technical Institute of Physics and Chemistry | Wang X.,CAS Xinjiang Technical Institute of Physics and Chemistry | Chen Z.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Ma P.,CAS Xinjiang Technical Institute of Physics and Chemistry
Applied Clay Science | Year: 2013

Vermiculite (Verm)/polystyrene (PS) nanocomposites were prepared by dispersing a doubly organo-modified Verm (DOVerm) in PS via in situ polymerization (DOVerm/PS 1/99, 3/97, 5/95, and 7/93 mass/mass ratios). The morphology of Verm/PS nanocomposites evolved three stages as the content of DOVerm decreased in the nanocomposites: intercalation at high filler content, intermediate state of intercalation to exfoliation, and exfoliation of Verm in PS matrix with a low filler content. The morphological changes of Verm/PS nanocomposites were confirmed by the X-ray diffraction (XRD) patterns and the transmission electron microscopy (TEM) images. Compared with the pure PS, the nanocomposites filled with Verm showed significant enhancements on thermal stability and dynamic mechanical properties. Interestingly, the nanocomposites filled with 1 and 7 mass% of DOVerm exhibited more pronounced effects of Verm on the properties. It was proved that the double organo-modification clearly enhanced the ultimate properties of the Verm/PS nanocomposites. © 2013 Elsevier B.V. Source


Gai M.,CAS Xinjiang Technical Institute of Physics and Chemistry | Gai M.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Gai M.,University of Chinese Academy of Sciences | Chen Z.,CAS Xinjiang Technical Institute of Physics and Chemistry | And 5 more authors.
Journal of Rare Earths | Year: 2013

The objective of this work was to develop possible materials for optically stimulated luminescence (OSL) dosimetric applications in real-time measurement. A novel material of LiMgPO4:Tb,Sm,B was prepared by solid-state diffusion method at 900 °C. The structure and optical properties of these phosphors were characterized by X-ray diffraction, fluorescence spectrophotometer, and OSL reader. The results showed that the full discrimination between the stimulation and emission spectra made them very fit for the optic-fibre dosimetry. The OSL vs. dose response was linear in the dose range of 0.1 to 216 Gy. It also showed a significant improvement in the stimulation time compared with LiMgPO4:Tb,B. Hence, the phosphor could be used in the real-time dosimeter based on the OSL technology for medical monitoring as well as for environmental dosimetry and space dosimetry. Source


Zou W.,University of Electronic Science and Technology of China | Wang Y.,University of Electronic Science and Technology of China | Wang Z.,University of Electronic Science and Technology of China | Zhou A.,University of Electronic Science and Technology of China | And 6 more authors.
Nanotechnology | Year: 2011

We report a novel method to fabricate ordered arrays of gold-polymer composite nanorods with the orientation in the vertical direction using block copolymer (BCP) film. The salt precursor is selectively infiltrated within vertically aligned cylindrical domains of the BCP film by immersing the template in a simple aqueous solution of HAuCl4. Scanning electron microscopy suggests that the salt might be uniformly positioned along the polymeric cylinders. A subsequent vacuum ultraviolet light irradiation simultaneously reduces the HAuCl4 into spherical gold nanoparticles with mean diameter around 2nm and removes the matrix of the BCP template to produce metal-polymer composite nanorods. While the solvent is methanol, the salt might be concentrated at the bottom of the BCP film. As a result, a periodic pattern of gold nanoparticles with average diameter around 11nm is formed where the BCP film is completely etched away. The solvent can effectively tune the spatial distribution of the salt precursor along the polymeric cylinders, which is responsible for the different morphologies of the photochemically fabricated nanostructures. © 2011 IOP Publishing Ltd. Source


Li J.Z.,University of Electronic Science and Technology of China | Li J.Z.,University of Sichuan | Li J.Z.,Xinjiang Key Laboratory of Electronic Information Materials and Devices | Wang Y.,University of Electronic Science and Technology of China | And 8 more authors.
Ultramicroscopy | Year: 2010

Three metal salts, i.e., AgNO3, HAuCl4, and KCl, were proposed as novel staining reagents instead of traditional RuO4 and OsO4 labeled with expensive price and extreme toxicity for scanning electron microscopy (SEM) imaging of microphase separated block copolymer film. A simple and costless aqueous solution immersion procedure could ensure selective staining of the metal slat in specific phase of the nanostructured copolymer film, leading to a clear phase contrasted SEM image. The heavy metal salt has better staining effect, demonstrating stable and high signal-to-noise SEM image even at an acceleration voltage as high as 30kV and magnification up to 250,000 times. © 2010 Elsevier B.V. Source

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