Ionic conductivity of ScF3 single crystals (ReO3 type)
- Authors: Sorokin N.I.1, Karimov D.N.1, Grebenev V.V.1, Sobolev B.P.1
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Affiliations:
- Shubnikov Institute of Crystallography
- Issue: Vol 61, No 2 (2016)
- Pages: 270-274
- Section: Physical Properties of Crystals
- URL: https://journals.rcsi.science/1063-7745/article/view/189896
- DOI: https://doi.org/10.1134/S1063774516020267
- ID: 189896
Cite item
Abstract
Electrical conductivity σ of ScF3 single crystals (sp. gr. \(Pm\overline 3 m\), ReO3 structure type) has been studied by impedance spectroscopy and compared with the electrical conductivity of rare earth HoF3 (β-YF3 type) and LaF3 (tysonite type) trifluorides. ScF3 crystals obtained by Bridgman directional solidification have ionic conductivity σ = 4 × 10–8 S/cm at 673 K. It is smaller than the σ values for LaF3 (sp. gr. \(P\overline 3 c1\)) and HoF3 (sp. gr. Pnma) single crystals by a factor of 104–105. The low conductivity of ScF3 crystals is due to the weak coordinating ability (coordination number CN = 6) and low electronic polarizability (αcat = 1.1 Å3) of Sc3+ ions. Mobile VF+ vacancies and less mobile interstitial Vi- ions (defects are formed according to the Frenkel mechanism) are involved in the ion transport. HoF3 and LaF3 single crystals have a high coordinating ability (CN = 9 for Ho3+ and CN = 11 for La3+) and a high electronic polarizability of cations (αcat = 1.6–1.9 Å3 for Ho3+ and αcat = 2.2 Å3 for La3+). Only mobile VF+ vacancies (defects are formed according to the Schottky mechanism) are involved in ion transport.
About the authors
N. I. Sorokin
Shubnikov Institute of Crystallography
Author for correspondence.
Email: nsorokin1@yandex.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333
D. N. Karimov
Shubnikov Institute of Crystallography
Email: nsorokin1@yandex.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333
V. V. Grebenev
Shubnikov Institute of Crystallography
Email: nsorokin1@yandex.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333
B. P. Sobolev
Shubnikov Institute of Crystallography
Email: nsorokin1@yandex.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333