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arXiv · 0908.2920

Diffuse scattering from the lead-based relaxor ferroelectric PbMg_1/3Ta_2/3O_3

A. Cervellino·S. N. Gvasaliya·O. Zaharko·B. Roessli·G. M. Rotaru·R. A. Cowley·S. G. Lushnikov·T. A. Shaplygina·M. -T. Fernandez-Diaz
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Abstract

The relaxor ferroelectric PbMg_1/3Ta_2/3O_3 was studied by single-crystal neutron and synchrotron x-ray diffraction and its detailed atomic structure has been modeled in terms of static Pb-displacements that lead to the formation of polar nanoregions. Similar to the other members of the Pb-based relaxor family like PbMg_1/3Nb_2/3O_3 or PbZn_1/3Nb_2/3O_3 the diffuse scattering in the [H,0,0]/[0,K,0] scattering plane has a butterfly-shape around the (h,0,0) Bragg reflections and is transverse to the scattering vector for (h,h,0) peaks. In the [H,H,0]/[0,0,L] plane the diffuse scattering is elongated along the <1,1,2> directions and is transverse to the scattering vector for (h,h,h) reflections. We find that a model consisting of correlated Pb-displacements along the <1,1,1>-directions reproduces the main features of the diffuse scattering in PbMg_1/3Ta_2/3O_3 adequately when the correlation lengths between the Pb-ion displacement vectors are longest along the <1,1,1> and <1,-1,0> and shortest along <1,1,-2> directions.

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A. Cervellino, S. N. Gvasaliya, O. Zaharko, B. Roessli, G. M. Rotaru, R. A. Cowley, S. G. Lushnikov, T. A. Shaplygina, M. -T. Fernandez-Diaz. 2009-11-19. Diffuse scattering from the lead-based relaxor ferroelectric PbMg_1/3Ta_2/3O_3. https://arxiv.org/abs/0908.2920

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