Coherent Sr3Ti2O7-Type Inclusions in the Sr2TiO4 Matrix Structure and Their Influence on XRD Patterns

Abstract

The effect of strontium deficiency on the microstructure of the Sr₂TiO₄ layered perovskite-like oxide with the crystal structure of the first term of the Ruddlesden–Popper series A_n+1B_nO_3n+1 is studied by powder XRD and high-resolution transmission electron microscopy. It is established that a strontium deficiency of ~5% (Sr_1.9TiO_3.9) can lead to the formation of coherent nano-sized inclusions (lamellas) with the structure of the second term Sr₃Ti₂O₇ of the series in the Sr₂TiO₄ matrix. The simulated XRD patterns show that the presence of such defects explains diffuse scattering effects and the redistribution of intensities of main reflections on the XRD patterns.