研究目的
To present a comprehensive set of polarized‐resolved vibrational modes of Ba3Sc4O9 and Sr3Sc4O9 compounds, measured in optimized spectroscopic conditions, besides their respective symmetry assignments.
研究成果
Ba3Sc4O9 and Sr3Sc4O9 compounds were obtained by conventional solid‐state method. Sintered bodies were produced aiming to perform optimized Raman spectroscopy measurements under different polarized light configurations. Group theoretical analysis at the center (Γ point) of the Brillouin zone predicted that 15A + 15E polar symmetries. The experimental results showed that 30 Raman modes were in fact observed, from which 15 could be experimentally assigned as totally symmetric A‐type modes and the remaining 15 as asymmetric E‐type ones. The Raman spectra of Ba‐containing and Sr‐containing ceramics exhibited differences in terms of their wavenumbers and relative intensities, which were discussed in terms of the respective ionic radii and molar masses. Finally, we believe that the perfect agreement between experimental data and group theory calculations can be useful to understand the recently reported exceptional luminescence properties for doped Ba3Sc4O9 and Sr3Sc4O9 compounds.
研究不足
The absence of Raman spectra of these materials in the literature difficults the comparison with our results.
1：Experimental Design and Method Selection:
Ba3Sc4O9 and Sr3Sc4O9 compounds were synthesized by solid‐state reactions using BaCO3, SrCO3, and Sc2O3 as starting materials. Stoichiometric amounts were mixed and ground thoroughly by using acetone as fluid medium to ensure complete homogeneity. The mixed powders were calcined in a conventional oven at 1200°C, for 8 hr, with intermediate regrinding. Cylindrical pucks were made by applying a pressure of 150 MPa, followed by sintering in a conventional oven for 8 hr at 1300°C, with heating/cooling rates of 5°C/min.
2：Sample Selection and Data Sources:
The crystal structure of the as‐synthesized powders as well as the sintered ceramics was studied by X‐ray diffraction (XRD). Transmission electron microscopy was employed to investigate the morphology and structure of the compounds.
3：List of Experimental Equipment and Materials:
PANalytical–EMPYREAN diffractometer with CuKα radiation, Tecnai G2‐20 (FEI) transmission microscope (TEM), Horiba LABRAM‐HR spectrometer with the
4：8 nm line of a helium‐neon laser as excitation source. Experimental Procedures and Operational Workflow:
6 Micro‐Raman scattering measurements were performed in backscattering configuration. Polarized micro‐Raman spectra were obtained on sintered ceramics by using appropriate interference filter for rejecting laser plasma lines, edge filters for stray light rejection, polarizers, and half‐wave plates.
5：Data Analysis Methods:
The resulting spectra were corrected for the Bose‐Einstein thermal factor.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
