Changes in the Jahn-Teller distortion at the metal-insulator transition in CMR manganites
| Autor: | C.-T. Chen, Jae-Hoon Park, F. Millange, B. Raveau, F. Studer, Olivier Toulemonde |
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| Rok vydání: | 1999 |
| Předmět: |
Colossal magnetoresistance
Condensed matter physics Chemistry Jahn–Teller effect Transition temperature Atmospheric temperature range Condensed Matter Physics Crystal Condensed Matter::Materials Science Magnetization Distortion Condensed Matter::Strongly Correlated Electrons General Materials Science Metal–insulator transition |
| Zdroj: | Journal of Physics: Condensed Matter. 11:109-120 |
| ISSN: | 1361-648X 0953-8984 |
| Popis: | CMR manganites were studied by x-ray absorption spectroscopy at the O K-edge above and below the transition temperature . In compounds which keep the insulating behaviour in the whole temperature range, the prepeak at the O K-edge remains unique upon cooling even in the case of the presence of a paramagnetic-ferromagnetic transition. In compounds showing a spontaneous transition from a paramagnetic-insulating state to a ferromagnetic-metallic one, the prepeak at the O K-edge is split into two components. A crystal field analysis of this behaviour is proposed based on the assumption of a strong reduction, upon cooling, of the octahedral distortion due to the dynamic Jahn-Teller splitting present above . This reduction of the crystal field distortion at is correlated to the transition to the metallic state and to the presence of the magneto-resistant effect. |
| Databáze: | OpenAIRE |
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