High-pressure behavior and equations of state of the cobaltates YBaCo4O7, YBaCo4O7+δ, YBaCoZn3O7 and BaCoO3−x
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Date
2012-12-01
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Publisher
Elsevier
Abstract
The compressibilities of the cobaltates YBaCo4O7, YBaCo4O7+δ, YBaCoZn3O7 and BaCoO3−x were investigated by in situ powder X-ray diffraction experiments up to 30GPa using diamond anvil cells. Pressure-induced phase transitions and amorphization were observed in all the samples. The onset of the pressure-induced phase transition and the onset of the amorphization were observed at ∼11.7 and 12.2GPa (YBaCo4O7), at ∼14.2 and 16.1GPa (YBaCo4O7+δ), and at ∼16.7 and 18.7GPa (YBaCoZn3O7), respectively. An attempt to laser anneal at high-pressure failed as it led to a decomposition of the YBaCo4O7 phase into a mixture of phases. Fits of second- and third-order Birch–Murnaghan equations-of-state to the p–V data result in B0=109(3)GPa for YBaCo4O7; B0=186(4)GPa and B′=1.5 for YBaCo4O7+δ; and B0=117(1)GPa for YBaCoZn3O7. The high-pressure behavior of the studied compounds was compared with isostructural compounds and it is shown that the oxygen-content has a very large effect on the high-pressure behavior of this class of materials. © 2012 Elsevier Inc.
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Keywords
Phase transformations, X-ray diffraction, Annealing, Pressure range mega pa 10-100, Oxygen, Cobalt
Citation
Juarez-Arellano, E. A., Avdeev, M., Yakovlev, S., Lopez-de-la-Torre, L., Bayarjargal, L., Winkler, B., Friedrich, A., & Kharton, V. V. (2012). High-pressure behavior and equations of state of the cobaltates YBaCo4O7, YBaCo4O7+δ, YBaCoZn3O7 and BaCoO3−x. Journal of Solid State Chemistry, 196, 209-216. doi:10.1016/j.jssc.2012.05.044