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

Abstract

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.

Influence of Isovalent ‘W’ Substitutions on the Structure and Electrical Properties of La2Mo2O9 Electrolyte for Intermediate-Temperature Solid Oxide Fuel Cells

“…Indeed, in the case of La 2 Mo 2 O 9, high oxide ion conductivity is observed after a structural phase transition from room-temperature monoclinic (α) to high-temperature cubic (β) at 580 • C [5]. A series of reports have been published regarding the quest to stabilize the β form down toward room temperature by substituting alkali, alkaline and rare earth cations in both the La and Mo sites [6][7][8][9][10][11][12][13][14][15][16][17].…”

Direct Observation of Oxide Ion Dynamics in La2Mo2O9 on the Nanosecond Timescale

“…Research into La 2 Mo 2 O 9 and related materials has largely been focused on trying to eliminate the abrupt structural phase transition and stabilize the highly conducting β-form at lower temperatures. This has been attempted by doping with a large number of different cations including alkali metals, − alkali earths, , rare earths, ,− Bi, − and Pb on the La site and transition metals ,,,,, and S on the Mo site. In many cases, this has been successful, leading to higher conductivity at lower temperatures than in the parent material.…”