Room temperature ferromagnetism of ZnO nanocrystals in amorphous ZnO–Al2O3 matrix
In this work, we demonstrate room temperature ferromagnetism of ZnO nanocrystals (NCs) embedded in alumina-based amorphous matrix. Our study has shown that solid solution occurred for lower Al concentration [≤x=0.09 for (Zn1−x,Alx)O]. No ferromagnetism appears in Al-doped ZnO with x≤0.09. With highe...
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Veröffentlicht in: | Applied physics letters 2009-08, Vol.95 (7) |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | In this work, we demonstrate room temperature ferromagnetism of ZnO nanocrystals (NCs) embedded in alumina-based amorphous matrix. Our study has shown that solid solution occurred for lower Al concentration [≤x=0.09 for (Zn1−x,Alx)O]. No ferromagnetism appears in Al-doped ZnO with x≤0.09. With higher Al concentration, alumina-based amorphous structure appeared and fully amorphous was found in the composition of (Zn0.30,Al0.70)O. Ferromagnetism was found in (Zn1−x,Alx)O with a threshold of 16 mol % of Al. The room temperature ferromagnetism was found to be attributed to ZnO NCs in an alumina-based amorphous ZnO–Al2O3 matrix. Ferromagnetism reached a maximum with a volume percentage of ZnO NCs to be ∼27 vol %. The detailed investigations (transmission electron microscopy, x-ray photoelectron spectroscopy, and superconducting quantum interference device) show that the optimized size of these NCs is in the range of 4–5 nm. No ferromagnetism appears if the sample contains a fully amorphous structure. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.3206654 |