Valence changes of manganese and structural phase transitions in Sr1−xPrxMnO3 (0.1≤x≤0.6)
| Autor: | Justin A. Kimpton, Nicolas Martin, Qinfen Gu, Brendan J. Kennedy, Ling-Yun Jang, Teck-Yee Tan, Qingdi Zhou, Zhaoming Zhang |
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| Rok vydání: | 2013 |
| Předmět: |
Phase transition
Valence (chemistry) Materials science Inorganic chemistry Crystal structure Condensed Matter Physics Magnetic susceptibility XANES Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography X-ray crystallography Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry Powder diffraction Phase diagram |
| Zdroj: | Journal of Solid State Chemistry. 201:115-127 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2013.01.034 |
| Popis: | Fifteen perovskite manganites Sr1−xPrxMnO3, x=0.1−0.6 in steps as fine as 0.025, have been synthesized by solid state methods and their crystal structures determined using synchrotron X-ray powder diffraction. At room temperature two first order phase transitions associated with changes in the orbital ordering and the tilting of the corner shared MnO6 octahedra are evident c u b i c / P m 3 ¯ m ⟹ x ≈ 0.15 t e t r a g o n a l / ( I 4 / m c m ) ⟹ x ≈ 0.45 o r t h o r h o m b i c / I m m a , with two phase regions associated with both transitions. Heating the Pr rich oxide Sr0.5Pr0.5MnO3 provides a rare example where chemical pressure and temperature result in a different sequence of transitions Imma– R 3 ¯ c – P m 3 ¯ m , reflecting the importance of the Pr 4f electrons. X-ray absorption near-edge structure (XANES) measurements at the Mn K and Pr L3 edges show the valence state of the Mn linearly decreases with increasing Pr content whereas the Pr remains +3 across the entire series. Magnetic susceptibility measurements for selected samples are presented. |
| Databáze: | OpenAIRE |
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