Effect of non-stoichiometry and synthesis temperature on the structure and conductivity of Ln2+xM2−xO7−x/2 (Ln=Sm–Gd; M=Zr, Hf; x=0–0.286)☆

Shlyakhtina, A.V.; Knotko, A.V.; Boguslavskii, M. V.; Stefanovich, S. Yu.; Колбанев, И. В.; Larina, Liudmila L.; Щербакова, Л. Г.

doi:10.1016/j.ssi.2006.11.001

Cited by 67 publications

(44 citation statements)

References 21 publications

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“…Note, first of all, the presence of very weak pyrochlore superstructure peaks ((111), (311), (331) (almost indiscernible), (511)) and strong fluorite substructure peaks. Similar diffraction patterns were obtained earlier for Eu 2.096 Hf 1.904 O 6.952 and Gd 2 Hf 2 O 7 [9]. This type of XRD pattern, with weak superstructure peaks, was also reported for pyrochlore-like Ln 2+x Zr 2−x O 7−δ in Ln 2 O 3 -ZrO 2 systems [11,12].…”

Section: Resultssupporting

confidence: 88%

“…So the bulk conductivity of Sm 2.096 Hf 1.904 O 6.952 is lower the conductivity of Eu 2.096 Hf 1.904 O 6.952 and Gd 2 Hf 2 O 7 samples. The data [9], obtained only at a limited number of frequencies, were confirmed by impedance spectroscopy data in this investigation.…”

Section: Resultssupporting

confidence: 78%

“…The materials were found to have high conductivity, approaching that of their zirconate analogues. The cation disorder in the hafnates, quantified by the density of Ln Hf ' + Hf Ln • defects, was close to that in the zirconates [9]. 3 and HfO 2 powders mechanically activated in an eccentric vibratory mill with a 120 cm 3 vial volume [10].…”

Section: Introductionmentioning

confidence: 60%

“…The first syntheses of Ln 2+x Hf 2−x O 7−δ (x=0.096; Ln = Sm, Eu) and Gd 2 Hf 2 O 7 with the use of mechanical activation, which seems to favour the formation of antisite defects in cubic oxides, were reported in [9]. The materials were found to have high conductivity, approaching that of their zirconate analogues.…”

Section: Introductionmentioning

confidence: 99%

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Study of bulk and grain-boundary conductivity of Ln2+xHf2−xO7−δ (Ln = Sm-Gd; x = 0, 0.096) pyrochlores

et al. 2009

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The electrical conductivity of new solid electrolytes Eu 2.096 Hf 1.904 O 6.952 and Gd 2 Hf 2 O 7 have been compared with those for different pyrochlores including titanates and zirconates Ln 2+x М 2−x O 7−δ (Ln = Sm-Lu; M = Ti, Zr; x= 0−0.81). Impedance spectroscopy data demonstrate that Eu 2.096 Hf 1.904 O 6.952 and Gd 2 Hf 2 O 7 synthesized from mechanically activated oxides have high ionic conductivity, comparable to that of their zirconate analogues. The bulk and grain-boundary components of conductivity in Sm 2.096 Hf 1.904 O 6.952 (Т synth =1600ºС), Eu 2.096 Hf 1.904 O 6.952 and Gd 2 Hf 2 O 7 (Т synth =1670ºС) have been determined. The highest bulk conductivity is offered by the disordered pyrochlores prepared at 1600ºC and 1670ºC:~1.5 × 10 −4 S/cm for Sm 2.096 Hf 1.904 O 6.952 , 5×10 −3 S/cm for Eu 2.096 Hf 1.904 O 6.952 and 3×10 −3 S/cm for Gd 2 Hf 2 O 7 at780ºС, respectively. The conductivity of the fluorite-like phases at the phase boundaries of the Ln 2+x М 2−x O 7−δ (Ln = Eu, Gd; M = Zr, Hf; x~0.286) solid solutions, as well as that of the high-temperature fluorite-like phases Ln 2+x М 2−x O 7−δ (Ln = Eu, Gd; M = Zr, Hf; x = 0−0.286), is lower than the conductivity of the disordered pyrochlores Ln 2+x М 2−x O 7−δ (Ln = Eu, Gd; M = Zr, Hf; x=0−0.096).

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Section: Resultssupporting

confidence: 88%

Section: Resultssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Study of bulk and grain-boundary conductivity of Ln2+xHf2−xO7−δ (Ln = Sm-Gd; x = 0, 0.096) pyrochlores

et al. 2009

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“…Recently, some interesting data concerning non-stoichiometric zirconates with fluorite/pyrochlore type of lattice were reported, e.g., better insulating properties [14]. The synthesis of non-stoichiometric europium zirconate and investigation of this process from a calorimetric point of view is the aim of this article.…”

Section: Introductionmentioning

confidence: 99%

Calorimetric study of Eu2O3–ZrO2 feedstock powders and sintered materials

Jucha

Moskal

Mikuśkiewicz

et al. 2016

J Therm Anal Calorim

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The synthesis of ceramic materials based on europia-zirconia system and obtained by solid-state reaction in high-temperature vacuum press was investigated. Firstly, phase composition and calorimetric behavior of feedstock powders was investigated. The second part of the paper concerns the synthesis process of non-stoichiometric mixtures of feedstock powders prepared by four different methods of mixing. The influence of the homogenization method on the calorimetric behavior and phase composition of obtained sinters was studied. Finally, the influence of the additional high-temperature annealing was also investigated. From the obtained results, it can be concluded that the mixing procedure had a very strong influence on the morphology of obtained sinters. This is due to the structural inhomogeneity, as indicated by differences in phase composition. The synthesis process has a gradual character, and the obtaining of materials with different level of homogeneity allowed the determination of the order of subsequent intermediate phase formation.

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Empirical Electronic Polarizabilities: Deviations from the Additivity Rule. II. Structures Exhibiting Ion Conductivity

Shannon

Kabanova

Fischer

2019

Crystal Research and Technology

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Ion conductivity in minerals and compounds is associated with continuous migration paths and leads to negative total electronic polarizability deviations [ = (α obs −α calc )/α obs )] up to 13%. Such deviations can be related to continuous migration paths determined in an earlier Voronoi-Dirichlet Partition (VDP) analysis of fast-ion conductors, that is, compounds such as LiB 3 O 5 with 1D conductivity, Li 4 SiO 4 with 2D conductivity, and Li 2 SO 4 with 3D conductivity. Using the Voronoi-Dirichlet (VD) method in this study, the migration paths and the dimensionality of many more compounds with negative polarizability deviations are identified. Continuous migration paths are found for the confirmed Li-ion conductors LiFePO 4 and Li 3 VO 4 and for the potential Li-ion conductors LiGeBO 4 , CsLiB 6 O 10 , Li 2 Ti 3 O 7 , LiMn 0.8 Fe 0.17 PO 4 , Li 2 NaPO 4 , and LiNaSO 4 . Similarly, continuous migration paths are found for the confirmed

show abstract

Effect of non-stoichiometry and synthesis temperature on the structure and conductivity of Ln2+xM2−xO7−x/2 (Ln=Sm–Gd; M=Zr, Hf; x=0–0.286)☆

Cited by 67 publications

References 21 publications

Study of bulk and grain-boundary conductivity of Ln2+xHf2−xO7−δ (Ln = Sm-Gd; x = 0, 0.096) pyrochlores

Study of bulk and grain-boundary conductivity of Ln2+xHf2−xO7−δ (Ln = Sm-Gd; x = 0, 0.096) pyrochlores

Calorimetric study of Eu2O3–ZrO2 feedstock powders and sintered materials

Empirical Electronic Polarizabilities: Deviations from the Additivity Rule. II. Structures Exhibiting Ion Conductivity

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