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Crystal growth of CaGdAlO4 by Cz method
|Qiangqiang Hu , Zhitai Jia , Xiuwei Fu , Yanru Yin , Jun Shu , Xutang Tao|
CaGdAlO4 (CGA) crystal with dimensions of Φ 30 × 30 mm3 was successfully grown by the Czochralski (CZ) method. The CaGdAlO4 crystal belongs to an isostructural family of crystals with the general formula ABCO4, where A denotes Ca or Sr, B represents rare-earth ion, C is Al or Ga. In this structure, the C exists in slightly distorted octahedral sites stacked in layers perpendicular to the c-direction. In the layers, the divalent A and trivalent B cations reside in ninefold coordinated sites which have distorted C4v Symmetry due to the random occupation of neighbouring sites by Ca2+ and Gd3+. It is a promising host material for ultrafast laser due to its disorder structure and high thermal conductivity.
The crystal growth was carried out in State Key Laboratory of Crystal Materials, Shandong University. The raw materials, including CaCO3 and Gd2O3, and Al2O3, were accurately weighed according to charges of stoichiometric composition and adequately mixed, and then pressed into tablets with dimensions of Φ 50 × 60 mm3. Afterwards, the tablets were sintered in air at 1350 °C for 45h before they were melted in an Ir crucible with a diameter of 60 mm and a height of 60 mm. An inert atmosphere of argon gas was adopted in order to prevent oxidation of the iridium crucible. After the crystal growth, a high quality CGA crystal along c-direction was grown.
Single crystal X-ray analysis was carried out on a Bruker SMART APEX-II equipped with CCD area-detector diffractometer at 296 K using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) with the f and w scans method. In addition, thermal properties including thermal expansion, specific heat, thermal diffusivity and thermal conductivity were investigated as a function of temperature. The transmission spectra and refractive indices were also measured.
 Jon-Paul R Wells, Mitsuo Yamaga Nobuhiro Kodama andThomas P J Han
Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Qiangqiang Hu
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-03-29 09:58 Revised: 2013-07-27 10:45