Structural Determination of the Charge Ordering Process in Nd0.5Ca0.5Mn1−xCrxO3 Manganites
| Autor: | Antoine Barnabé, W. Schuddinck, M. Hervieu, B. Raveau, G. Van Tendeloo |
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| Rok vydání: | 1999 |
| Předmět: |
Condensed matter physics
Chemistry Doping Crystal structure Condensed Matter Physics Crystallographic defect Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography Charge ordering Ferromagnetism Electron diffraction Lattice (order) Materials Chemistry Ceramics and Composites Physical and Theoretical Chemistry Solid solution |
| Zdroj: | Journal of solid state chemistry |
| ISSN: | 0022-4596 |
| Popis: | Structural properties of Cr-doped manganites Nd0.5Ca0.5Mn1−xCrxO3 with 0.02≤x≤0.07 have been studied versus temperature by electron diffraction and high-resolution electron microscopy between 90 and 300 K. All compositions show an incommensurate superstructure over the whole temperature domain, despite the fact that they are ferromagnetic and conductive below 150 K. The q vector (1/2−δ)a* decreases with increasing temperature for all compositions x. For a given temperature q also decreases with x. Room-temperature high-resolution electron microscopy images show point defects similar to those observed for other Ln0.5Ca0.5MnO3 manganites with Ln={Pr, Nd, Sm} and they also show intensity variations. Lattice images obtained at low temperature allow a better understanding of the charge ordering process. The low-temperature form of the Cr-doped manganites is not a perfectly doubled cell 〈〈2ap 2 ×2ap×ap 2 〉〉, but defects inducing a tripled cell occur pseudo-periodically. |
| Databáze: | OpenAIRE |
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