Crystals (Jul 2019)

Growth from the Melt and Properties Investigation of ScF<sub>3</sub> Single Crystals

  • Denis Karimov,
  • Irina Buchinskaya,
  • Natalia Arkharova,
  • Pavel Prosekov,
  • Vadim Grebenev,
  • Nikolay Sorokin,
  • Tatiana Glushkova,
  • Pavel Popov

DOI
https://doi.org/10.3390/cryst9070371
Journal volume & issue
Vol. 9, no. 7
p. 371

Abstract

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ScF3 optical quality bulk crystals of the ReO3 structure type (space group P m 3 ¯ m , a = 4.01401(3) Å) have been grown from the melt by Bridgman technique, in fluorinating atmosphere for the first time. Aiming to substantially reduce vaporization losses during the growth process graphite crucibles were designed. The crystal quality, optical, mechanical, thermal and electrophysical properties were studied. Novel ScF3 crystals refer to the low-refractive-index (nD = 1.400(1)) optical materials with high transparency in the visible and IR spectral region up to 8.7 µm. The Vickers hardness of ScF3 (HV ~ 2.6 GPa) is substantially higher than that of CaF2 and LaF3 crystals. ScF3 crystals possess unique high thermal conductivity (k = 9.6 Wm−1К−1 at 300 K) and low ionic conductivity (σ = 4 × 10−8 Scm−1 at 673 К) cause to the structural defects in the fluorine sublattice.

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