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State Reaction Method (state + reaction_method)

Distribution by Scientific Domains
Physics and Astronomy66%

Kinds of State Reaction Method

  • solid state reaction method
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    Selected Abstracts

    Growth of YCOB single crystals by flux technique and their characterization

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2008
    R. Arun Kumar
    Abstract Nonlinear optical single crystals of YCOB with good optical quality were grown by the flux technique for the first time. Polycrystalline YCOB samples were synthesized by solid state reaction method. The thermal analysis of the sample was performed with lithium carbonate flux in different weight proportions and the growth temperature was optimised. Single crystals of YCOB with dimensions 3 × 3 × 5 mm3 were obtained by the method of ,slow-cooling'. The grown crystals were characterized by XRD, UV-VIS-NIR, EDAX, FTIR and etching studies. The powder XRD pattern revealed the formation of YCOB compound. The lattice parameters were identified through single crystal XRD studies. The UV-VIS-NIR results showed that the crystal has a sharp cutoff at 220 nm and is nearly 55% transparent over a wide wavelength range enabling applications in the UV region. The EDAX measurement revealed the ,flux-free' crystal formation. The presence of the functional groups belonging to the YCOB crystals was identified by the FTIR results. ,Hillock-like' patterns are observed in the etching studies. The primary emphasis in this study is laid to describe ,flux technique' as an alternative method to grow YCOB crystals. The results are presented and discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    The preparation of ZnGa2O4 doped with Mn-Mg and Tm for green and blue phosphors

    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 1 2006
    Binod Kumar Singh Non-member
    Abstract Phosphor powders of zinc gallate (ZnGa2O4) with Mg and Mn for green and Tm-Mg for blue luminescence were prepared by solid state reaction method for their improved luminescent properties. Green-luminescence emitting ZnMnGa2O4 reached maximum intensity at Mn = 0.005 mol% and further improvement was achieved by the addition of Mg2+. Tm-Mg based zinc gallate phosphor exhibited a strong blue emission, centered at ,420 nm with the maximum intensity achieved for 0.003 mol% of Mg and 0.015 mol% of Tm. This study established the possibilities of controlling the luminescent characteristics of zinc gallate by adding various elements. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Low-Temperature Firing and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, Ceramics with ZnB2O4 Glass Addition

    INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2008
    Li-Xia Pang
    Low-temperature sintered Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, microwave dielectric ceramics with ZnB2O4 glass (ZBG) addition were prepared by the conventional solid state reaction method. The sintering behavior, microstructure, and microwave dielectric properties of Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, ceramics with ZBG addition were investigated. The ZBG addition lowered the densified temperature of Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, ceramics from 1150°C to 940°C. The dielectric constants of Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, ceramics decreased from 40 to 34 and the temperature coefficient of resonant frequency (,f) changed gradually from +12.7 to ,25.7 ppm/°C as ZBG addition increased from 0 to 8 wt%. The Qf values increased greatly from 20,500 GHz of pure Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, to 26,900 GHz when 5 wt% ZBG was added. Ca[(Li1/3Nb2/3)0.8Ti0.2]O3,, ceramics with 8 wt% ZBG addition sintered at 940°C show good microwave dielectric properties with ,r,32.5, Qf,20,600 GHz, and ,f,,25.7 ppm/°C. The relationship between dielectric properties and microstructure was also discussed. [source]

    Phase diagram of the NdFe1,xRhx AsO superconductor

    PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 3-4 2010
    H. Y. Shi
    Abstract Polycrystalline samples with a nominal composition of NdFe1,xRhx AsO (0 , x , 0.25) were synthesized using a solid state reaction method. Bulk superconductivity with a maximum TC = 13 K is observed in the x = 0.1 sample. A temperature,composition phase diagram is established for the NdFe1,xRhx AsO system based on the electrical resistivity and magnetization measurements. A first-order-like transition from an antiferromagnetic state to the superconducting state at a critical Rh-doping point xC , 0.045 is observed in the present phase diagram. The value for the upper critical field ,0Hc2(0) is estimated to be about 26 T for the x = 0.10 sample by using the Werthamer,Helfand,Hohenberg theory. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Pb substitution effect on the normal and superconductivity states transport of polycrystalline MgB2

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2006
    M. Zouaoui
    Abstract A series of samples of Mg1,xPbxB2 were synthesized by the conventional solid state reaction method. Its temperature dependence of resistivity was studied from the zero resistivity temperature Tc up to 300 K. In order to more understand the main reason of the decreases of Tc, we analyse the resistivity versus temperature data in the normal state using Bloch-Grüneisen formula. The Debye temperature, ,D, has been extracted from the fits. ,D is seen to decrease with the lead substitution from 1280 K to 835 K. Using ,D and Tc, the electron-phonon interaction parameter ,, has been given by McMillan equation. The values of , increase from 0.70 to 0.84 respectively for x = 0% and x = 1% sample. The decrease in Tc is argued mainly by the decrease in the density of states at the Fermi level N(EF) with Pb concentration than the decrease in ,D. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Effects of Zn doping on YBaCuO superconductor

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2006
    M. Mahtali
    Abstract In this work we present a study of Zn impurity effects on the YBa2Cu3O7,, high Tc superconducting ceramics prepared by the solid state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA) techniques, and resistivity measurements are used to characterize the YBa(Cu1,xZnx)3O7,, samples. The obtained results show that, for example, the value of the transition critical temperature is decreasing up to 80 K caused by the substitution of Zn for Cu in the interval 0 , x , 0.01. Also, the peritectic transformation of superconducting phase undergoes a displacement to lower temperatures compared with pure YBaCuO. On the basis of the obtained results, the effects of Zn doping on the structural and electronic properties are explained. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]