Synthesis and μ-Raman scattering of Ruddlesden-Popper ceramics Sr3Ti2O7, SrLa2Al2O7 and Sr2LaAlTiO7

Influence of B‐site cation in lattice dynamics of bilayered Ruddlesden–Popper Sr3B2O7 (B = Zr, Mo, Sn, Hf) compounds

“…The Raman and IR phonons of the bilayered tetragonal compounds Sr 3 B 2 O 7 (B = Zr, Mo, Sn, Hf) in the phase I4/mmm have been calculated by a study based on a comparison with the double‐layered tetragonal compounds Sr 3 Ti 2 O 7 , Sr 3 Mn 2 O 7 , and Sr 3 Fe 2 O 7 . The Sr 3 Ti 2 O 7 , Sr 3 Mn 2 O 7 , and Sr 3 Fe 2 O 7 compounds have similar structures, symmetries, and space groups with the studied compounds in the present work, so for comparative study, these compounds have been considered 21–28 . The Sr 3 Mn 2 O 7 compound in phase I4/mmm has been studied by Guedes et al 27 and in their work, the values of lower wavenumbers of A 1g modes are in the range of 243–170 cm − 1 , and for B 1g mode, it is 320 cm − 1 .…”

Relating the structure, properties, and activities of nanostructured SrTiO3 and SrO–(SrTiO3)n (n = 1 and 2) for photocatalytic hydrogen evolution

“…3) show bands at 178, 198, 274, 500, and 633 cm −1 which can be assigned to the A 1g , E g , E g , A 1g , and A 1g modes respectively which is consistent with a previous report. 32 A defect-induced excitation was also observed at 92 cm −1 . The band corresponding to the A 1g mode was observed to be more intense in both Sr 2 TiO 4 and Sr 3 Ti 2 O 7 , which could be due to symmetric stretching of the oxygen lattice.…”

Synthesis, structural and optical‐vibration properties of Ba3Sc4O9 and Sr3Sc4O9 ceramics

“…Once the phonon modes of rhombohedral compounds belong to only two different irreducible representations, we were also stimulated to look for an experimental determination of the symmetry of the characteristic phonon features. In order to attain better results, the materials were sintered at high temperatures, as usual in our investigations regarding Raman bands aiming to identify and assign all the predicted modes …”

“…These compounds were synthesized by conventional solid‐state route and then submitted to sintering procedures at high temperatures in order to obtain ceramic bodies with suitable microstructures for inspection under polarized micro‐Raman conditions. Previous works were published by our research group with this procedure in different materials, proving our ability to assign the Raman active modes in sintered ceramics in adequate scattering configurations . Thus, the goal of this work is to present a comprehensive set of polarized‐resolved vibrational modes of Ba 3 Sc 4 O 9 and Sr 3 Sc 4 O 9 compounds, measured in optimized spectroscopic conditions, besides their respective symmetry assignments.…”