Effect of coherency of domain walls on X-ray diffraction diagrams: Case a crystal with a low tetragonality

Les diagrammes de diffraction des rayons X d'une poudre ou d'une ceramique de BaTiO 3 tetragonal ont ete etudies. Une correlation entre les caracteristiques des profils des raies de diffraction (intensite, forme, position,...) et la microstructure en domaines ferroelectriques a ete mise en evidence. A partir d'une approche numerique, le calcul des diagrammes de diffraction montre que la modification des profils des raies de diffraction du compose tetragonal est fortement dependante de la microstructure en domaines ferroelectriques. Ce a du prendre en compte l'existence d'un certain degre de coherence dans les murs de domaines entre deux domaines a 90° adjacents. Il a par ailleurs ete mis en…

Influence of Twinning Microstructure of Crystals with Low Tetragonality on a X-Ray Diffraction

The intensity distributions of the X-rays scattered in the tetragonal single crystal, which represent a complex of the twin domains separated by the coherent parallel boundaries, are simulated. The calculations are performed by using the Monte Carlo method within the framework of a kinematical approach. The thickness distributions of the twin domains are defined according to the geometrical, Gaussian and log normal functions. ‘Critical’ effects of the X-ray scattering are found, namely there is transformation of the tetragonal doublet into singlet or multiplet. As demonstrated, each of characteristics of the tetragonal doublet profile depends on a few parameters of the twin microstructure o…

Peculiarities of X-Ray Diffraction in Crystals with Diffuse Boundaries of Twin on System {011}, <011>