| Autor: |
Stanulis, Andrius, Katelnikovas, Arturas, Salak, Andrei N., Seibutas, Povilas, Ivanov, Maksim, Grigalaitis, Robertas, Banys, Juras, Kareiva, Aivaras, Ramanauskas, Rimantas, Barron, Andrew R. |
| Zdroj: |
Inorganic Chemistry; September 2019, Vol. 58 Issue: 17 p11410-11419, 10p |
| Abstrakt: |
We report that luminescence of Eu3+ion incorporated into Ruddlesden–Popper phases allows monitoring phase transition in powders (instead of single crystals), in a time-efficient manner (compared to neutron diffraction), and importantly, with greater sensitivity than previous methods. Crystal structure and dielectric response of undoped and 0.5%Eu3+-doped Sr3Sn2O7ceramics were studied as a function of temperature over the temperature range of 300–800 K. The luminescence studies of 0.5%Eu3+-doped Sr2SnO4and Sr3Sn2O7samples were performed in the temperature range of 80–500 K. These results were compared with the respective dependences for the undoped compounds. The structural transformations in 0.5%Eu3+-doped Sr3Sn2O7were found at 390 and 740 K. The former is associated with the isostructural atomic rearrangement that resulted in a negative thermal expansion along two of three orthorhombic crystallographic axes, while the latter corresponds to the structural transition from the orthorhombic Amamphase to the tetragonal I4/mmmone. A similar temperature behavior with the structural transformations in the same temperature ranges was observed in undoped Sr3Sn2O7, although the values of lattice parameters of the Eu3+-doped and undoped compounds were found to be slightly different indicating an incorporation of europium in the crystal lattice. A dielectric anomaly associated with a structural phase transition was observed in Sr3Sn2O7at 390 K. Optical measurements performed over a wide temperature range demonstrated a clear correlation between structural transformations in Eu3+-doped Sr2SnO4and Sr3Sn2O7and the temperature anomalies of their luminescence spectra, suggesting the efficacy of this method for the determination of subtle phase transformations. |
| Databáze: |
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