Abstract
The relationship between the superionic transport in fluorite phases M 1 − x R x F2 + x (M = Ca, Sr, or Ba; R are rare earth elements) and their defect structure has been analyzed. The superionic conductivity of M 1 − x R x F2 + x crystals is provided by the high concentration of charge carriers. However, the carrier concentration is several tens of times lower than the concentration of anionic defects, which is explained by the presence of defect regions (DRs), which partially block carriers. The dependence of the superionic conductivity of M 1 − x R x F2 + x phases on the RF3(x) content has a percolation nature. Crystals of these phases are divided into two groups with respect to the percolation threshold: x p, 1 = 2–3 mol % RF3 and x p, 2 = 7–8 mol % RF3. The corresponding DR volumes are 3000–4000 Å3 (x p, 1) and 500–700 Å3 (x p, 2). The x p, 1, and x p, 2 values correlate, respectively, with the octahedral cubic {M 14 − p R p F68 − 69} and tetrahedral {M 4 − p R p F26} clusters, which are DR cores. The DR model and cluster structure are indicative of the heterogeneity of nonstoichiometric M 1 − x R x F2 + x crystals at the nanoscale level with respect to the chemical composition and the electrical and crystallochemical (coordinations of M and R) characteristics.
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References
N. I. Sorokin and B. P. Sobolev, Crystallogr. Rep. 52(5), 842 (2007).
B. P. Sobolev, A. M. Golubev, and P. Errero, Crystallogr. Rep. 48(1), 141 (2003).
B. P. Sobolev, The Rare Earth Trifluorides, Part 2: Introduction to Materials Science of Multicomponent Metal Fluoride Crystals (Institute of Crystallography, Moscow, 2001; Institut d’Estudis Catalans, Barcelona, 2001).
B. P. Sobolev, The Rare Earth Trifluorides, Part 1: The High Temperature Chemistry of the Rare Earth Trifluorides (Institute of Crystallography, Moscow, 2000; Institut d’Estudis Catalans, Barcelona, 2000).
J. S. Anderson, Problems of Nonstoichiometry, Ed. by A. Rabenau (North Holland, Amsterdam, 1970), p. 355.
V. B. Aleksandrov and L. S. Garashina, Dokl. Akad. Nauk SSSR 189(2), 307 (1969).
A. K. Ivanov-Shits, N. I. Sorokin, P. P. Fedorov, et al., Fiz. Tverd. Tela 25(6), 1748 (1983).
A. K. Ivanov-Shits, N. I. Sorokin, P. P. Fedorov, et al., Solid State Ionics 31(4), 253 (1989).
A. K. Ivanov-Shits, N. I. Sorokin, P. P. Fedorov, et al., Solid State Ionics 31(4), 269 (1989).
A. K. Ivanov-Shits, N. I. Sorokin, P. P. Fedorov, et al., Solid State Ionics 37(1-2), 125 (1990).
N. I. Sorokin, Elektrokhimiya 42(7), 828 (2006).
N. I. Sorokin, D. N. Karimov, E. A. Sul’yanova, et al., Crystallogr. Rep. 55(4), 662 (2010).
A. K. Ivanov-Shits, N. I. Sorokin, B. P. Sobolev, et al., Fiz. Tverd. Tela 28(8), 2552 (1986).
N. I. Sorokin, Kristallografiya 38(1), 245 (1993).
A. S. Dworkin and M. A. Bredig, J. Phys. Chem. 72(4), 1277 (1968).
P. P. Fedorov and B. P. Sobolev, J. Less-Common Met. 63, 31 (1979).
V. M. Goldschmidt, T. Barth, G. Lunde, et al., Geochemische Verteilungsgesetze der Elemente. VII. Skrift Norske Vid. Acad. Oslo. I. Mat.-Nat. Klasse 1(2), 1 (1926).
Crystals with the Fluorite Structure, Ed. by W. Hayes (Clarendon, Oxford, 1974).
A. F. Cheetham, B. E. F. Fender, B. J. Taylor, et al., Solid State Commun. 8(3), 171 (1970).
D. J. Bevan, O. Greis, and J. Strahle, Acta Crystallogr. A 36, 889 (1980).
L. A. Muradyan, B. A. Maksimov, and V. I. Simonov, Koord. Khim. 12(10), 1398 (1986).
P. P. Fedorov, Buttl. Soc. Cat. Cien. 12(2), 349 (1991).
S. Hull and C. C. Wilson, J. Solid State Chem. 100, 101 (1992).
J. P. Laval, A. Mikou, B. Frit, et al., Solid State Ionics 28–30, 1300 (1988).
N. B. Grigor’eva, L. P. Otroshchenko, B. A. Maksimov, et al., Crystallogr. Rep. 41(1), 45 (1996).
N. B. Grigor’eva, B. A. Maksimov, L. P. Otroshchenko, et al., Crystallogr. Rep. 43(3), 376 (1998).
A. M. Golubev and V. I. Simonov, Kristallografiya 31(3), 478 (1986).
B. P. Sobolev, A. M. Golubev, L. P. Otroshchenko, et al., Crystallogr. Rep. 48(6), 944 (2003).
E. A. Sul’yanova, V. N. Molchanov, and B. P. Sobolev, Crystallogr. Rep. 53(4), 565 (2008).
B. A. Maksimov, Yu. B. Gubina, E. L. Belokoneva, et al., Crystallogr. Rep. 47(3), 372 (2002).
D. J. M. Bevan, M. J. McCall, S. E. Ness, et al., Eur. J. Solid State Chem. 25(5–6), 517 (1988).
B. A. Maksimov, X. Solans, A. P. Dudka, et al., Crystallogr. Rep. 41(1), 50 (1996).
E. A. Sul’yanova, V. N. Molchanov, I. A. Verin, et al., Crystallogr. Rep. 54(3), 516 (2009).
A. M. Golubev, Kristallografiya 34(6), 1457 (1989).
A. M. Golubev, L. P. Otroshchenko, V. N. Molchanov, et al., Crystallogr. Rep. 54(3), 423 (2009).
A. K. Ivanov-Shits, N. I. Sorokin, L. A. Muradyan, et al., Proc. IX All-Union Conf. on the Physical Chemistry and Electrochemistry of Ionic Melts and Solid Electrolytes, Sverdlovsk, 1987), Vol. 3,Part 1, p. 109.
P. P. Fedorov and B. P. Sobolev, Kristallografiya 37(5), 1210 (1992).
O. Greis and J. M. Haschke, Handbook on the Physics and Chemistry of Rare Earths, Ed. by K. A. Gscheidner and L. R. Eyring (North-Holland, Amsterdam, 1982), Vol. 5, Ch. 45, p. 387.
F. Kadlec, F. Moussa, P. Simon, et al., Mater. Sci. Eng. B 57, 234 (1999).
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Original Russian Text © N.I. Sorokin, A.M. Golubev, B.P. Sobolev, 2014, published in Kristallografiya, 2014, Vol. 59, No. 2, pp. 275–285.
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Sorokin, N.I., Golubev, A.M. & Sobolev, B.P. Structural mechanisms of superionic conductivity in M 1−x R x F2+x single crystals. Crystallogr. Rep. 59, 238–247 (2014). https://doi.org/10.1134/S1063774514010155
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DOI: https://doi.org/10.1134/S1063774514010155