Local environment surrounding magnetic impurity atoms in a structural phase transition of Co-doped TiO2 nanocrystal ferromagnetic semiconductors
| Autor: | Yun-Liang Soo, Y. H. Kao, Sun Jin Kim, George Kioseoglou, P. I. Gouma, John B. Parise, P. Sujatha Devi, Richard J. Gambino |
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| Rok vydání: | 2002 |
| Předmět: |
Anatase
Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Crystal structure Magnetic semiconductor Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter::Materials Science Crystallography Ferromagnetism Nanocrystal Impurity X-ray crystallography Condensed Matter::Strongly Correlated Electrons Magnetic impurity |
| Zdroj: | Applied Physics Letters. 81:655-657 |
| ISSN: | 1077-3118 0003-6951 |
| Popis: | The local environment surrounding magnetic impurity atoms and the host crystal structure of codoped TiO2 (TiO2:Co) nanocrystal ferromagnetic semiconductors have been investigated using the x-ray absorption fine structure and powder diffraction techniques. It has been found that the magnetic Co impurity atoms substitute for the Ti sites in an anataselike local environment through a structural phase transition when the material changes from an amorphous phase to a mixture of anatase and rutile crystal structures and then to a rutile structure as a result of increasing the anneal temperature. This result reveals an interesting feature that the local structure around magnetic impurity atoms can remain practically unchanged while the material undergoes drastic structural variations and a loss of room-temperature ferromagnetism. |
| Databáze: | OpenAIRE |
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