کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1332449 | 979042 | 2010 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Symmetry of LaAlO3 nanocrystals as a function of crystallite size Symmetry of LaAlO3 nanocrystals as a function of crystallite size](/preview/png/1332449.png)
Properties of LaAlO3 nanocrystallites obtained by the precipitation method, doped with praseodymium and chromium ions were examined by spectroscopic means. Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and electronic spectroscopy proved that symmetry of LaAlO3 crystallites depends on their size. At room temperature the smallest obtained crystals (average size ∼5 nm) have cubic symmetry, while the largest ones (average size over 110 nm) exhibit rhombohedral symmetry. Possible explanations for this phenomenon are discussed.
Graphical AbstractThe 77 K emission spectra of LaAlO3:Pr3+ nanocrystallites codoped with Cr3+ as a function of the annealing temperature. Intensities were normalized to the maximum of the 3P0→3H4 transition. The R line at 13633 cm−1 vanish with decreasing the nanocrystals size and is absent for the smallest ones.Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 183, Issue 9, September 2010, Pages 2095–2100