Growth of Sm1 – ySryF3 – y (0 < y ≤ 0.31) Crystals and Investigation of Their Properties
- Authors: Sorokin N.I.1, Karimov D.N.1, Samsonova N.V.1, Ivanova A.G.1, Fedorov V.A.1, Sobolev B.P.1
-
Affiliations:
- Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,” Russian Academy of Sciences
- Issue: Vol 64, No 3 (2019)
- Pages: 488-495
- Section: Crystal Growth
- URL: https://journals.rcsi.science/1063-7745/article/view/194019
- DOI: https://doi.org/10.1134/S1063774519030246
- ID: 194019
Cite item
Abstract
Sm1 – ySryF3 – y (0 < y ≤ 0.31) crystals have been grown from melt by directional solidification in a fluorinating atmosphere. The crystals have been studied by X-ray diffraction and optical spectroscopy, and their fluorine-ion conductivity σdc, density ρ, and refractive indices nD have been measured. It is established that Sm3+ ions are not reduced to Sm2+ during crystal growth. The reversible polymorphic α ↔ β-SmF3 transition does not make it possible to obtain bulk (>1–3 mm3) samples of the tysonite phase (of LaF3 type) at y < 0.02. The dependences ρ(y) and nD(y) for the crystals are descending. The dependence σdc(y) exhibits nonmonotonic behavior; the maximum σdc value (1.6 × 10–4 S/cm) at 293 K is observed for the Sm0.98Sr0.02F2.98 crystal. At y = 0.31, an eutectic composite 69SmF3 × 31SrF2 is formed, whose conductivity is σdc = 6 × 10–8 S/cm, a value smaller than σdc for the crystal with y = 0.02 by a factor of ~3 × 103. The carrier concentration nmob and its mobility μmob have been calculated for Sm1 – ySryF3 – y (0.02 ≤ y ≤ 0.25) within the hopping conductivity model. For the crystal with the highest conductivity (Sm0.98Sr0.02F2.98), nmob = 4.0 × 1020 cm–3 and µmob = 2.5 × 10–6 cm2/(V s) at T = 293 K.
About the authors
N. I. Sorokin
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333
D. N. Karimov
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Author for correspondence.
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333
N. V. Samsonova
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333
A. G. Ivanova
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333
V. A. Fedorov
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333
B. P. Sobolev
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics,”Russian Academy of Sciences
Email: dnkarimov@gmail.com
Russian Federation, Moscow, 119333