High ionic conductivity in the pyrochlore-type Gd2−yLayZr2O7 solid solution (0≤y≤1)

Díaz-Guillén, J.A.; Díaz-Guillén, M.R.; Padmasree, K.P.; Fuentes, Antonio F.; Santamarı́a, J.; León, Carlos

doi:10.1016/j.ssi.2008.07.015

Cited by 107 publications

(35 citation statements)

References 25 publications

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“…12,14 It may be noted that the pyrochlore-type Gd 2Ày La y Zr 2 O 7 (0 y 1) and (Nd 2Àx Zr x ) Zr 2 O 7þx/2 (x ¼ 0-0.78) solid electrolytes exhibit cubic symmetry with space group Fd 3 m with superstructure ordering. 20,21 But the present samples do not show lattice superstructure, except undoped La 2 Mo 2 O 9 .…”

Section: Resultscontrasting

confidence: 50%

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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Articles you may be interested inSpontaneous formation of circular and vortex ferroelectric domain structure in hexagonal YMnO3 and YMn0.9Fe0.1O3 prepared by low temperature solution synthesisCorrelation of structure and ion conduction of La 2Àx Y x Mo 2 O 9 (0 x 0.2) has been investigated. The cubic symmetry with space group P2 1 3 and other structural parameters are obtained from Rietveld refinement of X-ray diffraction patterns of Y doped samples. The average lanthanum-oxygen and molybdenum-oxygen distances are obtained from the electron density contour plot. The transmission electron microscopic study confirms the cubic nature of the samples and also provides an estimate of thickness of the grain boundary. The scanning transmission electron microscope energy dispersive spectrometer mapping confirms the different orientations of grains. The composition dependence of the ionic conductivity has been correlated with that of O2 and O3 site occupancies in the [O1La 3 Mo] antitetrahedral unit. The different vibrational modes in the low frequency region due to vibration of Mo-O bands are confirmed from the analysis of FTIR and Raman spectra. The full widths at half maximum of most of the Mo-O bands are found to be independent of Y doping. Additionally, the shifts in the position of Raman bands are correlated with unit cell parameter using Gr€ uneisen constant. V C 2015 AIP Publishing LLC.

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Section: Resultscontrasting

confidence: 50%

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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“…Ternary Ln 2 B 2 O 7 oxides (Ln=lanthanides; B=Ti 4+ , Zr 4+ ) adopting the pyrochlore structure, have attracted great interest because of their high structural flexibility, which might be altered via processing and/or doping. The series exhibit a broad spectrum of chemical and physical properties of scientific and technological interest such as high ionic conductivity and high thermal resistance, to mention some . Moreover, they are attractive component materials for electrochemical devices and thermal insulating coatings.…”

Section: Introductionmentioning

confidence: 99%

Electrical and thermophysical properties of mechanochemically obtained lanthanide hafnates

et al. 2017

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This contribution presents the synthesis and thermophysical characterization of seven lanthanide hafnates Ln2Hf2O7 (Ln=Sm3+, Eu3+, Gd3+, Dy3+, Y3+, Ho3+, Yb3+); the title samples were prepared at room temperature by mechanically milling stoichiometric mixtures of the corresponding elemental oxides. Irrespective of the lanthanide ion involved, milling promotes the formation of highly disordered fluoritelike materials. Postmilling thermal treatments facilitate the formation of the fluorite ordered derivative, the pyrochlore structure, but only for the larger lanthanides (Sm3+, Eu3+, Gd3+). Impedance spectroscopy measurements revealed that these materials show a moderate‐to‐good oxygen ion conductivity at high temperatures; furthermore, those adopting the pyrochlore structure give higher σdc and lower Edc than their fluorite analogues (σdc at 750°C>10−3 S·cm−1 vs <5·10−4 S·cm−1, respectively). The same trend also holds for the thermal resistivity at high temperatures; the highest thermal resistivity and thus, lowest κ was obtained for Eu2Hf2O7 (κ~1.3·W·m−1·K−1 at 800°C). Therefore, Ln2Hf2O7 phases might be attractive component materials for electrochemical devices and thermal insulating coatings.

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“…In addition to ABO 3 perovskite, A 2 B 2 O 7 pyrochlore is also a multifunctional material featuring ferroelectricity, 1 radiation damage resistance, 2 high ionic conductivity, 3 superconductivity, 4 and geometrically frustrated magnetism. 5 These wide varieties of physical properties are due to its complicated atomic configurations and resultant electronic structures.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental investigation of defect formation / migration in Gd2Ti2O7: General rule of oxide-ion migration in A2B2O7 pyrochlore

et al. 2016

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We investigated the intrinsic defect formation energy and oxide-ion migration mechanism in Gd2Ti2O7 pyrochlore. It was found that the vacancy formation energy of Gd is lower than that of Ti. For the oxygen vacancy, O(48f) was found to show lower vacancy formation energy than O(8b). The formation energy of the vacancy complex showed that the Gd vacancy is accompanied with the O(48f) vacancy, which is consistent with our experiment. The migration energy of O(48f) along the <100> direction, which is dominant migration path for ionic conduction, was calculated to be 0.43 eV. On the other hand, we found that Gd vacancy increases O(48f) migration energy. For example, the migration energy of O(48f) along the <100> direction was increased to be 1.36 eV by the local compressive strain around Gd vacancy. This finding could explain our previous experimental result of decreasing conductivity with increasing Gd deficiency. Along with the oxide-ion migration mechanism in Gd2Ti2O7, O(48f) migration energies along both <100> and <110> directions for various A2B2O7 pyrochlore structures were investigated. As a general trend of oxide-ion migration in the pyrochlore structure, we propose that O(48f) migration along the <100> direction is governed by the strength of B–O bonding. On the other hand, the ratio of ionic radius B/A is proposed to determine O(48f) migration along the <110> direction in A2B2O7 pyrochlore.

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High ionic conductivity in the pyrochlore-type Gd2−yLayZr2O7 solid solution (0≤y≤1)

Cited by 107 publications

References 25 publications

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Electrical and thermophysical properties of mechanochemically obtained lanthanide hafnates

Theoretical and experimental investigation of defect formation / migration in Gd2Ti2O7: General rule of oxide-ion migration in A2B2O7 pyrochlore

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