Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9761586 | Solid State Ionics | 2005 | 7 Pages |
Abstract
A combination of variable temperature X-ray powder diffraction, ac impedance spectroscopy and differential thermal analysis (DTA) has been used to characterise phase transitions in the Bi2ZrxV1âxO5.5â(x/2)âδ, BIMEVOX system. At low substitution levels α-, β-, and γ-phase BIMEVOX structures are observed as a function of temperature with some evidence for an intermediate phase, É, seen between β and γ phases on heating. At x = 0.10 the β-phase is observed at room temperature with a transition to the γ-phase at around 500 °C. There is evidence for a subtle phase transition at around 200 to 250 °C in the variation of refined cell parameters and the Arrhenius plot of conductivity for this composition that may be associated with a vacancy ordering phenomenon. For the x = 0.19 composition, despite near equivalence of a and b unit cell parameters, variation in the unit cell c-parameter, DTA and Arrhenius plots of conductivity show evidence of a βâγ transition between 450 and 500 °C and that the true symmetry of the low temperature phase is likely to be orthorhombic.
Keywords
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Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
W. Wrobel, I. Abrahams, F. Krok, A. Kozanecka, S.C.M. Chan, M. Malys, W. Bogusz, J.R. Dygas,