Ionic conductivity of multicomponent fluorite-structured fluorides

Trnovcová, V.; Федоров, П. П.; Buchinskaya, I. I.; Kubliha, Marián

doi:10.1134/s1023193511050144

Cited by 7 publications

(7 citation statements)

References 5 publications

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“…This is due to the difference in the band electronic structure of lead and cadmium difluorides from the fluorides of alkaline earth elements, as well as the large difference in the ionic radii of Pb 2+ (1.43 Å) and Cd 2+ (1.24 Åf or coordination number 8 [41]). X-ray diffraction analysis of Pb 0.67 Cd 0.33 F 2 [42] crystals revealed a high concentration of anion vacancies V • F even at room temperature, which is 25 ± 2% in the main anionic positions, and the corresponding number of interstitial ions F ′ i . " Crystallochemical" anti-Frenkel defects(F ′ i + V • F ) caused by Pb 2+ substitutions for Cd 2+ , are retained with decreasing temperature, in contrast to thermally stimulated anti-Frenkel defects [8] in the matrix β-PbF 2 .…”

Section: ) Solid Solutionmentioning

confidence: 99%

Effect of iso- and heterovalent cation substitutions on the superionic Faraday transition in fluorite-type modification β-PbF-=SUB=-2-=/SUB=-

Sorokin

2022

Physics of the Solid State

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The influence of isovalent substitutions of Pb2+-> Cd2+ and heterovalent substitutions of Pb2+-> Sc3+ on a superionic Faraday transition in Pb1-xCdxF2 (x=0.33) and Pb1-xScxF2+x (x=0.1) solid solutions based on the fluorite-type modification β-PbF2 with sp. gr. Fm 3 m has been studied. The Faraday phase transition can be characterized by the temperature Ttrλ corresponding to maximum on the heat capacity curve and temperature Ttrα corresponding to the beginning of the structural disorder anion sublattice. Both of these temperatures are found on the temperature conductivity dependence sigmadc(T) of β-PbF2, Pb0.67Cd0.33F2 and Pb0.9Sc0.1F2.1 crystals. The values of Ttrλ and Ttrα in solid solutions compared with β-PbF2 (Ttrλ=715±10 K, Ttrα = 597±12 K) decrease by 100-110 and 30-45 K for Pb0.67Cd0.33F2 and Pb0.9Sc0.1F2.1, respectively. Decreasing of temperature Ttrλ leads to an increase in temperature interval of existence of the superionic state. For T>Ttrλ the anionic conductivity of fluorite-type Pb0.67Cd0.33F2, Pb0.9Sc0.1F2.1, and β-PbF2 crystals reaches anomalously high values of sigmadc = 1-2 S/cm (873 K) at an ion transfer activation enthalpy equals to Hsigma~0.3 eV. Keywords: phase transitions, fluorides, fluorite structure, ionic conductivity, solid solutions.

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Section: ) Solid Solutionmentioning

confidence: 99%

Effect of iso- and heterovalent cation substitutions on the superionic Faraday transition in fluorite-type modification β-PbF-=SUB=-2-=/SUB=-

Sorokin

2022

Physics of the Solid State

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“…Согласно структурным исследованиям [9,20] во флюоритовых кристаллах Pb 1−x M x F 2 (M = Sn, Cd) наблюдается недозаселенность основных позиций фтора 8c пр. гр.…”

Section: кристаллофизическая модельunclassified

Подвижность носителей заряда в монокристалле и нанокерамике суперионного проводника Pb-=SUB=-1-x-=/SUB=-Sn-=SUB=-x-=/SUB=-F-=SUB=-2-=/SUB=- (x=0.2)

Сорокин¹

2019

Физика Твердого Тела

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A crystallophysical model of ion transfer in the superionic Pb_1 – _ x Sn_ x F_2 conductor with a fluorite (CaF_2) structure is proposed. The concentration dependence of the ionic conductivity of Pb_1 – _ x Sn_ x F_2 single crystals and poly- and nanocrystals is analyzed. The single-crystal form of the superionic conductor is characterized by the highest conductivity. The mobility and concentration of anionic charge carriers in a single crystal and ceramics of Pb_1 – _ x Sn_ x F_2 ( x = 0.2) is calculated on the basis of structural and electrophysical data. The mobility of carriers μ_mob = 2.5 × 10^–6 cm^2/s V (at 293 K) in a single crystal is seven times higher than in nanoceramic. The concentration of carriers n _mob = 1.7 × 10^21 and 3.6 × 10^21 cm^3 (4.5 and 9.5% of the total number of anions) for a single crystal and nanoceramic, respectively. The comparison of isostructural Pb_0.8Sn_0.2F_2, Pb_0.67Cd_0.33F_2, and Pb_0.9Sc_0.1F_2.1 single crystals shows that anionic carriers have a maximum mobility in the β-PbF_2 and SnF_2 based solid solution.

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“…Doping with a mixture of rare-earth fluorides does not provide any improvement in the conductivity mostly because the lattice mismatch is increased by mixing different cations without providing more defects or new conduction paths [62]. Doping with a mixture of rare-earth fluorides does not provide any improvement in the conductivity mostly because the lattice mismatch is increased by mixing different cations without providing more defects or new conduction paths [62].…”

Section: Fluorite-type Fluoride Ion Conductorsmentioning

confidence: 99%