Morphological and Structural changes of Ca _<i>x</i> Sr _{1− <i>x</i>} TiO ₃ Powders Obtained by the Microwave‐Assisted Hydrothermal Method

Abstract

Ca x Sr 1− x TiO 3 samples were synthesized by the microwave‐assisted hydrothermal method. The X‐ray diffraction results indicate that strontium calcium titanates powders show two crystalline structures: perovskite cubic and orthorhombic. The ultraviolet‐visible spectra show that the band gap energies decrease with the Ca addition, suggesting imperfections or defects in the forbidden band of the titanates. The photoluminescence spectra show a broad band, which is usually observed at low temperatures in perovskite‐type crystals. The nanoparticles show a nonuniform distribution with polyhedral morphology and spherical agglomerates, which change to faceted surfaces suggesting that the sample can reach other morphologies which ensure symmetry of lowest energy.