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Growth and Neutron Diffraction Investigation of Ca3NbGa3Si2O14 and La3Ga5.5Nb0.5O14 Crystals

  • Kaurova, I. A. Moscow State Open University, 3 Entuziastov Street, Aleksandrov 601655, Russia
  • Kuz’micheva, G. M. Lomonosov Moscow University of Fine Chemical Technology, 86 Vernadskogo Prospekt, Moscow 119571, Russia
  • Rybakov, V. B. Lomonosov State University, Vorobyovy Gory, Moscow 119992, Russia
  • Cousson, A. Laboratoire Leon Brillouin, Cea/Saclay, 91191 Gif-sur-Yvette Cedex, France
  • Zaharko, O. Laboratory for Neutron Scattering, ETZ Zurich & Paul Scherrer Institute (PSI), CH 5232 Villigen, Switzerland
  • Domoroshchina, E. N. Lomonosov Moscow University of Fine Chemical Technology, 86 Vernadskogo Prospekt, Moscow 119571, Russia
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Published in:
  • Journal of Materials. - Hindawi Limited. - 2013, vol. 2013, p. 1-6
English Langanite (La3Ga5.5Nb0.5O14, growth atmosphere: 99% Ar + 1% O2) and kanigasite (Ca3NbGa3Si2O14, growth atmosphere: 100% Ar) crystals grown by the Czochralski technique in Ir crucibles along <0001> direction have been firstly investigated by neutron diffraction. The difference between the compositions of upper (La2.935(2)□0.065)(Ga0.450Nb0.550(3))Ga3(Ga1.965(4)□0.035)(O13.90(1)□0.10) and lower (La2.940(1)□0.060)(Ga0.590Nb0.410(2))Ga5(O13.82(1)□0.18) parts of orange langanite crystal was found. It was established that the colorless Ca3NbGa3Si2O14 crystal grown by using the single-crystal charge has the composition (Ca2.95□0.05(1))NbGa3Si2O14 and is less defective in comparison to the yellow one grown by using the charge prepared by conventional solid-state reaction. For Ca3NbGa3Si2O14 and La3Ga5.5Nb0.5O14 crystals the possibility of microtwin formation (two unit cells connected by the translation: 1/2 z) was revealed for the first time. It was found that the difference between the color of crystals is attributed to the qualitative differentiation of oxygen vacancies.
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  • English
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gold
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https://folia.unifr.ch/global/documents/96110
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