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arXiv · 0707.4095

High-pressure study of X-ray diffuse scattering in ferroelectric perovskites

Sylvain Ravy·Jean-Paul Itie·Alain Polian·Michael Hanfland
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Abstract

We present a high-pressure x-ray diffuse scattering study of the ABO$_3$ ferroelectric perovskites BaTiO_3 and KNbO_3. The well-known diffuse lines are observed in all the phases studied. In KNbO_3, we show that the lines are present up to 21.8 GPa, with constant width and a slightly decreasing intensity. At variance, the intensity of the diffuse lines observed in the cubic phase of BaTiO_3 linearly decreases to zero at $\sim 11$ GPa. These results are discussed with respect to x-ray absorption measurements, which leads to the conclusion that the diffuse lines are only observed when the B atom is off the center of the oxygen tetrahedron. The role of such disorder on the ferroelectric instability of perovskites is discussed.

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Sylvain Ravy, Jean-Paul Itie, Alain Polian, Michael Hanfland. 2007-07-27. High-pressure study of X-ray diffuse scattering in ferroelectric perovskites. https://doi.org/10.1103/physrevlett.99.117601

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