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

X-ray diffraction (XRD) diagrams of tetragonal BaTiO3 as powder or ceramic materials are analyzed. The correlation between features of the line profil es and crystal domain microstructure are evidenced. Using numerical calcula tions of XRD patterns, peculiarities in the tetragonal profile changes were studied depending on the parameters of the single crystal domain microstru cture providing the domain walls would be coherent. It is shown that these peculiarities are similar to those that are experimentally observed.