Crystal Research and Technology

Cover image for Vol. 47 Issue 12

December 2012

Volume 47, Issue 12

Pages 1213–1283

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Issue Information
    4. Contents
    5. Original Paper
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      Cover Picture

      Version of Record online: 14 DEC 2012 | DOI: 10.1002/crat.201290020

  2. Issue Information

    1. Top of page
    2. Cover Picture
    3. Issue Information
    4. Contents
    5. Original Paper
    1. You have free access to this content
      Issue Information

      Version of Record online: 14 DEC 2012 | DOI: 10.1002/crat.201290021

  3. Contents

    1. Top of page
    2. Cover Picture
    3. Issue Information
    4. Contents
    5. Original Paper
    1. You have free access to this content
  4. Original Paper

    1. Top of page
    2. Cover Picture
    3. Issue Information
    4. Contents
    5. Original Paper
    1. Synthesis, growth, morphology of the semiorganic nonlinear optical crystal L-glutamic acid hydrochloride and its structural, thermal and SHG characterizations (pages 1217–1230)

      P. Dhanasekaran and K. Srinivasan

      Version of Record online: 21 NOV 2012 | DOI: 10.1002/crat.201200053

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      One of the halide derivatives of L-glutamic acid which was identified as a semiorganic nonlinear optical material, L-glutamic acid hydrochloride [HOOC(CH2)2CH(NH2)COOH.HCl], was grown as bulk single crystal and its significant properties were characterized. The stoichiometric title compound was synthesized and the solubility of its recrystallized form in DD water was determined in the temperature range 30–80 °C by gravimetric method. Structural confirmation was carried out by powder X-ray diffraction study through lattice parameter verification. Optical quality smaller dimension single crystals were grown from aqueous solution by self nucleation through slow evaporation of solvent method and a large dimension single crystal was grown by slow cooling method with reversible seed rotation technique. Morphological importances of different growth facets of the as grown crystals were studied through optical goniometry. Unit cell structure of the grown crystal was refined by single crystal X-ray diffraction analysis, functional groups present in the crystal responsible for various modes of vibrations were confirmed by FTIR spectroscopy analysis, thermal stability of the grown crytal was analysed by TG/DTA and DSC and second harmonic generation (SHG) of a fundamental Nd:YAG laser beam by Kurtz technique. Results indicate that the grown crystal is in stoichiometric composition and has significant improvement in its thermal and SHG properties when compared to pure L-glutamic acid polymorphs.

    2. Morphology-controlled CaMoO4 nanorods via a facile microwave-assisted EDTA chelating agent process (pages 1231–1236)

      Lina Wang, Yan Sun, Chunsheng Li, Yaozu Wang, Xuegang Ma, Yandi Wang, Shuoshuo Li, Zhijia Zhang, Peijuan Ma and Guanghua Cui

      Version of Record online: 6 DEC 2012 | DOI: 10.1002/crat.201200148

      Thumbnail image of graphical abstract

      This work reports on the shape-controlled synthesis of CaMoO4 nanorods via a high-efficient microwave irradiation-assisted chelating agent method. The phase and microstructure of these materials were systematically characterized by X-ray diffraction and field-emission scanning electron microscopy. It is noteworthy that EDTA plays pivotal roles as the complexing and capping agent in the oriented growth of uniform CaMoO4 nanorods. The synthetic process gives the guidance to understand the morphological evolution of CaMoO4 microstructures in microwave system, and provides a facile and designed strategy to fabricate functional one dimensional metallic molybdates.

    3. Large-scale synthesis of SiC nanowires from polysiloxane and wood powder composites (pages 1237–1242)

      Jian-mei Pan, Qing-bo Lu, Xiao-nong Cheng, Xue-hua Yan and Cheng-hua Zhang

      Version of Record online: 21 NOV 2012 | DOI: 10.1002/crat.201200175

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      Large-scale SiC nanowires were prepared by directly annealing polysiloxane and wood powder composites without catalyst assistant at 1420 °C under argon atmosphere. SiC nanowires are up to tens of micrometers in length and the diameters are in the range of 30–150 nm. Most nanowires are smooth and straight in morphology. High-resolution TEM image shows that SiC nanowires grow along the [111] direction. The vapor–solid mechanism was proposed to explain the growth procedure of SiC nanowires. The present work provides an efficient and simple strategy for large-scale production of SiC nanowires.

    4. Crystal growth and spectral properties of Nd:Ca5(BO3)3F (pages 1243–1248)

      Mingjun Xia and R. K. Li

      Version of Record online: 6 DEC 2012 | DOI: 10.1002/crat.201200208

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      A neodymium doped Ca5(BO3)3F single crystal with size up to 51×48×8 mm3 has been grown by the top seeded solution growth (TSSG) technique with a Li2O-B2O3-LiF flux. The spectra of absorption and fluorescence were measured at room temperature. According to Judd-Ofelt (J-O) theory, the spectroscopic parameters were calculated and the J-O parameters Ω2, Ω4, Ω6 were obtained as follows: Ω2 = 1.41×10−20cm2, Ω4 = 3.18×10−20cm2, Ω6 = 2.11×10−20cm2. The room temperature fluorescence lifetime of NCBF …

    5. Template effects on the morphology of ZnO via colloidal crystals with different functional groups (pages 1249–1254)

      Ming Fu, Jinfang Cui, Mei Yang, Rong Jiang, Dawei He and Yongsheng Wang

      Version of Record online: 26 OCT 2012 | DOI: 10.1002/crat.201200296

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      ZnO is an important wide bandgap compound semiconducting material and exhibits a wide range of novel structures that can be grown by tuning the growth rates along its fast growth directions. Highly ordered macroporous materials by using colloidal crystal template method are of great interest in many fields including photonic crystals and catalysts. In this study, ZnO with highly ordered porous structure was deposited by different electrochemical method. Nanomeshes, inverse opal structures, …

    6. Detailed study of defects in thin fullerite films (pages 1255–1268)

      K. O. Graivoronska, M. Klimenkov, Yu. M. Solonin, S. A. Nepijko and G. Schönhense

      Version of Record online: 27 NOV 2012 | DOI: 10.1002/crat.201200304

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      The structural investigations of fullerite films were performed using high-resolution electron microscopy, electron diffraction and electron energy loss spectroscopy and X-ray photoelectron spectroscopy. In particular defects such as dislocations, stacking faults and twins were studied in details. It was shown that fullerite films could be characterized by a face-centered cubic (f.c.c.) structure with lattice parameter a = 1.416 nm. They are distinguished for their rich polytypic structure that is caused by breaking of alteration of closely packed planes of (111) type. The quantitative method based on information theory using the “run-length encoding” algorithm was suggested to evaluate the degree of disorder in the f.c.c structure of thin fullerite films.

    7. Numerical investigation of magnetic field effect on pressure in cylindrical and hemispherical silicon CZ crystal growth (pages 1269–1278)

      F. Mokhtari, A. Bouabdallah, A. Merah and H. Oualli

      Version of Record online: 6 DEC 2012 | DOI: 10.1002/crat.201200309

      Thumbnail image of graphical abstract

      The effect of axial magnetic field of different intensities on pressure in silicon Czochralski crystal growth is investigated in cylindrical and hemispherical geometries with rotating crystal and crucible and thermocapillary convection. As one important thermodynamic variable, the pressure is found to be more sensitive than temperature to magnetic field with strong dependence upon the vorticity field. The pressure at the triple point is proposed as a convenient parameter to control the homogeneity of the grown …

    8. Microwave hydrothermal synthesis and photocatalytic properties of ZnWO4 nanorods (pages 1279–1283)

      Guoqiang Tan, Lili Zhang, Shasha Wei, Ao Xia and Huijun Ren

      Version of Record online: 27 NOV 2012 | DOI: 10.1002/crat.201200410

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      Cd2+-doped ZnWO4 nanorods have been synthesized at 200 °C with microwave hydrothermal method, using Zn(NO3)2·6H2O, Na2WO4·2H2O and CdCl2 as raw materials. The effects of Cd2+ doping contents on the structure and morphology of the product were studied. The results show that Cd2+ doping into the crystal lattice of ZnWO4 nanopowder makes the powder orientationally grow along (010), (110) and (200) crystal planes to form the nanorods. The bigger Cd2+ doping contents are, the more obviously ZnWO4 nanorods grow. Meanwhile, the nanopowder is gradually transformed from monoclinic phase into the orthogonal phase. As the charge transference medium between the interfaces, Cd2+ restrains the combination of holes and electrons. After doped, the photocatalytic properties of ZnWO4 nanorods are increased. When Cd2+ doping content is 20%, the Cd2+-doped ZnWO4 nanorods showed the highest degradation rate up to 98% in 2 h.

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