Nature of ionic conductivity of lanthanide tungstates with imperfect scheelite structure

Пестерева, Н. Н.; Vyatkin, I.; Lopatin, D. A.; Guseva, A. F.

doi:10.1134/s1023193516110094

Cited by 8 publications

(3 citation statements)

References 10 publications

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“…Experimental procedure of Tubandt Method.-The Tubandt method 31,32 was used to study the effective transport numbers. The tripartite cell was constructed from three equally weighted discs/ pellets in series as follows:…”

Section: Methodsmentioning

confidence: 99%

Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Morkhova,

Koroleva,

Egorova

et al. 2024

ECS Adv.

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The CaNb2O6 and ZnNb2O6 columbites (Sp.gr. Pbcn) were studied as oxygen ion conductors both theoretically and experimentally. A theoretical approach included geometrical-topological analysis, bond valence site energy (BVSE) and density functional theory (DFT) calculations. The BVSE approach showed the possibility of pure oxygen ions diffusion with migration energies less than 0.45 eV in both compounds. However, DFT calculations indicated the possibility of diffusion of both anions and cations. The single-phases columbites were synthesized by the Pechini method for accurately determine charge carriers type and investigated by impedance spectroscopy, by the Tubandt method, which confirmed the absence of cationic conductivity, and measured the electrical conductivity as a function of oxygen partial pressures. The CaNb2O6 sample had the pure oxygen-ionic conductivity ∼2×10-6 S cm–1 at 800 °C (Ea = 0.82 eV), while the ZnNb2O6 had a similar conductivity value due to mixed ionic-electronic contribution (Ea = 0.83 eV). The electromotive force method also showed the predominance of the ionic type of conductivity in CaNb2O6, while ZnNb2O6 has a mixed conductivity with ion transport number of about 0.4. Additionally, we synthesized Ti-doped samples MNb2-xTixO6-0.5x (M = Mg, Ca; x = 0.1, 0.2) to study the doping effect on conducting properties.

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Section: Methodsmentioning

confidence: 99%

Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Morkhova,

Koroleva,

Egorova

et al. 2024

ECS Adv.

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“…In the case of Ho 2 (WO 4 ) 3 there were some small peaks in its diffraction pattern, which belonged to the γ-Sc 2 (WO 4 ) 3 -phase (hydrated at room conditions) [18]. It is generally accepted [19] that 1/3 of all sites within the Ln sublattice in the Ln (Ln = La-Ho) tungstates with the imperfect scheelite-type structure remain unoccupied. The Ln vacancies tend to form an ordered superstructure at low temperatures, while statistically disordered structures tend to form upon heating.…”

Section: Introductionmentioning

confidence: 99%

“…A lot of publications available in the literature describe properties of well-crystallized Ln tungstates prepared by the solid-state synthesis method [6,7,9,19,22]. This method requires the use of high calcination temperatures (usually ≥ 1000 • C) and long processing times (usually few tens hours) and cannot be used to monitor changes with the crystal structure during its emergence.…”

Section: Introductionmentioning

confidence: 99%

Features of the Phase Preferences, Long- and Short-Range Order in Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) with Their Relation to Hydration Behavior

et al. 2022

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The effect of synthesis conditions on the features of the long- and short-range order of Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) powders synthesized via coprecipitation of salts has been studied by a complex of physico-chemical techniques including synchrotron X-ray powder diffraction, X-ray absorption spectroscopy, Raman and infrared spectroscopy, and simultaneous thermal analysis. It was found that crystallization of amorphous precursors begins at 600 ∘C/3 h and leads to the formation of the monoclinic structure with sp. gr. C12/c1(15) for Ln2(WO4)3 (Ln = Gd, Dy) and with sp. gr. P121/a1(14) for Ln = Yb, whereas crystallization of Ho precursor requires even higher temperature. After annealing at 1000 ∘C, the P121/a1(14) phase becomes the dominant phase component for all heavy lanthanoid types except for Ln = Gd. It was shown that the Ln (Ln = Dy, Ho, and Yb) tungstates with the P121/a1(14) monoclinic structure correspond to trihydrates Ln2(WO4)3·3H2O formed due to a rapid spontaneous hydration under ambient conditions. It was concluded that the proneness to hydration is due to a specific structure of the P121/a1(14) phase with large voids available to water molecules. Modifications in the local structure of Ln-O coordination shell accompanying the structure type change and hydration are monitored using EXAFS spectroscopy.

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Structure and electrical properties of Ln2(MO4)3(Ln = La or Sm; M = W or Mo) nanoceramics

Jayalekshmy¹,

John²,

Thomas³

et al. 2023

J Aust Ceram Soc

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Nature of ionic conductivity of lanthanide tungstates with imperfect scheelite structure

Cited by 8 publications

References 10 publications

Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Features of the Phase Preferences, Long- and Short-Range Order in Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) with Their Relation to Hydration Behavior

Structure and electrical properties of Ln2(MO4)3(Ln = La or Sm; M = W or Mo) nanoceramics

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Nature of ionic conductivity of lanthanide tungstates with imperfect scheelite structure

Cited by 8 publications

References 10 publications

Exhaustive Study of Electrical Conductivity in the MNb2−x TixO6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Exhaustive Study of Electrical Conductivity in the MNb2−x TixO6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Features of the Phase Preferences, Long- and Short-Range Order in Ln2(WO4)3 (Ln = Gd, Dy, Ho, Yb) with Their Relation to Hydration Behavior

Structure and electrical properties of Ln2(MO4)3(Ln = La or Sm; M = W or Mo) nanoceramics

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Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites

Exhaustive Study of Electrical Conductivity in the MNb_2−xTixO_6–0.5x (M = Mg, Ca, Zn; x = 0, 0.1, 0.2) Columbites