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Structure locale dans un ferroélectrique relaxeur : BaTi(1-x)Zr(x)O3

Abstract : Relaxor ferroelectrics are characterized by a large, frequency-dependent peak of the dielectric permittivity as a function of temperature. This behaviour is generally attributed to the presence of nanometre-sized polar regions. One of the experimental challenges is the determination of the structural nature of such regions, which requires the use of local structural probes. This manuscript presents the study of the local structure in the perovskite-type relaxor ferroelectrics BaTi1-xZrxO3 (0.25 ≤ x ≤ 0.50), by means of X-ray absorption (EXAFS and XANES) and pair distribution function determination from neutron total scattering. We could determine the Ti4+ and Zr4+ cation displacements with respect to the centre of their oxygen cage. The main result is that the Ti4+ cations play a major role in the local polarisation in BaTi1-xZrxO3 relaxors. Moreover, it is shown that the deformation of the ZrO6 octahedra directly depends on the local distribution of the Ti and Zr atoms in the solid solution.
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https://tel.archives-ouvertes.fr/tel-00196922
Contributor : Claire Laulhé <>
Submitted on : Thursday, December 13, 2007 - 6:24:11 PM
Last modification on : Thursday, November 19, 2020 - 12:59:52 PM
Long-term archiving on: : Monday, April 12, 2010 - 7:26:28 AM

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  • HAL Id : tel-00196922, version 1

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Claire Laulhé. Structure locale dans un ferroélectrique relaxeur : BaTi(1-x)Zr(x)O3. Mécanique [physics.med-ph]. Institut National Polytechnique de Grenoble - INPG, 2007. Français. ⟨tel-00196922⟩

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