| Autor: |
Genevois, Cécile, Bazzaoui, Haytem, Boyer, Marina, Ory, Sandra, Ledemi, Yannick, Messaddeq, Younès, Pitcher, Michael J., Allix, Mathieu |
| Zdroj: |
Inorganic Chemistry; August 2021, Vol. 60 Issue: 16 p12339-12354, 16p |
| Abstrakt: |
SrREGa3O7melilite ceramics with large rare-earth elements (RE= La to Y) are famous materials especially known for their luminescence properties. Using an innovative approach, the full and congruent crystallization from glass process, SrREGa3O7transparent polycrystalline ceramics with small rare earth elements (RE= Dy–Lu and Y) have been successfully synthesized and characterized. Interestingly, compared to the classic tetragonal (P4̅21m) melilite structure composed of mixed Sr/REcationic sites, these compositions can crystallize in a 3 × 1 × 1 orthorhombic (P21212) superstructure. A detailed study of the superstructure, investigated using different techniques (synchrotron and neutron powder diffraction, STEM-HAADF imaging, and EDS mapping), highlights the existence of a Sr/REcation ordering favored by a large Sr/REsize mismatch and a sufficiently small REcation. An appropriate control of the synthesis conditions through glass crystallization enables the formation of the desired polymorphs, either ordered or disordered. The influence of this tailored cationic ordering/disordering on the REluminescent spectroscopic properties have been investigated. A stronger structuration of the REemission band is observed in the ordered ceramic compared to the disordered ceramic and the glass, whose band shapes are very similar, indicating that the REenvironments in the glass and disordered ceramic are close. |
| Databáze: |
Supplemental Index |
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