Fine grain barium titanate: ferroelectric domains and X-ray diffraction diagram

Through three different studies using various kinds of BaTiO/sub 3/ samples: as a powder while heating over the Curie temperature; as a green ceramic as a function of the forming pressure; as a ceramic while applying a D.C. field. It is shown how X-ray diffraction is able to give information about the evolution of the 90/spl deg/ ferroelectric domain microstructure.

Ferroelectric domains in BaTiO3powders and ceramics evidenced by X-ray diffraction

Abstract Through three different studies, using BaTiO3 samples, as a powder while heating over the Curie temperature, and as a ceramic while applying an electric field, it is shown how X-ray diffraction (XRD) is able to give information about the evolution of the ferroelectric domain microstructure. Firstly, the relative intensities of the 002 and 200 lines, as a function of the applied electric field, exhibit the motion of the 90[ddot] domain walls. However, XRD is unable to provide any distinction between two 180[ddot] domains. Secondly, the profile of those two lines and of the other double (hhl), (lhh) lines is particular: the unusual diffracted intensity between such double lines has t…

A New Possibility for Powder Diffraction: The Characterization of the Domain Microstructure in a Ferroelectric Material

Ferroelectric Domain Walls in BaTiO3: Fingerprints in XRPD Diagrams and Quantitative HRTEM Image Analysis

The structure of ferroelectric domain walls in BaTiO3 has been investigated through two complementary approaches, a global one by the fine analysis of X-ray diffraction patterns, the other essentially local via a quantitative image analysis method developed and applied to High Resolution Transmission Electron Microscopy images. These two original approaches converge towards a clear description of 90○ walls which are shown to be a 4–6 nm wide region where the crystallographic discontinuity is accommodated by irregular atomic displacements. The results given here demonstrate that the usual structural theoretical description of walls commonly accepted for energy calculations are far too simpli…

Contribution of Ferroelectric Domains on Diffraction Line Profiles of BaTiO<sub>3</sub>

X-Ray diffraction diagram evolution of a BaTiO3ceramic under an electric field

Abstract The X-ray diffraction diagrams of a coarse grained pure BaTiO3 ceramic have been recorded as a function of the applied electric D.C. field. This field was perpendicular to the X-ray incoming surface. The experimental device used allows to record diffraction diagrams while the electric field step by step increases. The intensity ratio of the 002 line over the 200 line increases with the applied electric field. The evolution of the X-ray diffraction line intensities is in correlation with the first polarization curve of the ferroelectric ceramic. These results evidence a contribution of the 90° ferroelectric domains pattern to the X-ray diffraction diagram of BaTiO3.

Conception d'une chambre de diffraction RX haute température pour l'étude de l'adsorption d'un gaz par un solide sous haute pression

Le caractere original et innovateur de la chambre d'analyse qui est presentee dans ce travail repose sur son champ d'utilisation large, en particulier dans le domaine de l'adsorption sous haute pression d'un gaz condensable. Cette chambre qui a ete specialement concue au Laboratoire de Recherches sur la Reactivite des Solides de l'Universite de Bourgogne est susceptible d'operer dans des domaines etendus de pression et de temperature, respectivement (10 -4 -10 4 ) hPa et (20 - 350) °C. Un doigt de gant en beryllium monte sur un passage electrique assure l'etancheite de l'enceinte reactionnelle; l'echantillon est chauffe par conduction. La chambre qui est placee dans une enceinte externe (eq…