Browsing by Author "Lopez-de-la-Torre, L"

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    High-pressure behavior and equations of state of the cobaltates YBaCo4O7, YBaCo4O7+δ, YBaCoZn3O7 and BaCoO3−x
    (Elsevier, 2012-12-01) Juarez-Arellano, EA; Avdeev, M; Yakovlev, S; Lopez-de-la-Torre, L; Bayarjargal, L; Winkler, B; Friedrich, A; Kharton, VV
    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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    Observation of a ferroelastic phase transition in the YBaCo4-xZnxO7+δ system
    (DFG, 2009) Juarez-Arellano, EA; Avdeev, M; Lopez-de-la-Torre, L; Yakovlev, S; Bayarjargal, L; Winkler, B; Friedrich, A
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