research papers
Substitution in the perovskite A site releases internal structural stress as a result of a better matching of the A—O and B—O distances, leading to less distorted phases (transition from monoclinic to orthorhombic). Symmetry-adapted mode decomposition revealed that the out-of-phase tilt of BO6 octahedra slightly varies with Sr content, whereas the in-phase tilt strongly decreases to almost vanish for x > 0.5, anticipating a transition to a more symmetric structure.