Fragmentation of Fe2O3 nanoparticles driven by a phase transition in a flame and their magnetic properties

The size and crystalline phase changes of Fe2O3 nanoparticles formed in a H2/O2 flame have been investigated. At flame temperatures below 1350 °C, the mean particle size increased monotonously with the distance from the burner edge; but in high-temperature flames above 1650 °C, it suddenly decreased...

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Veröffentlicht in:Applied physics letters 2003-12, Vol.83 (23), p.4842-4844
Hauptverfasser: Yang, Sangsun, Yi, Ji-Hyun, Son, Soonil, Jang, Jungho, Altman, Igor S., Pikhitsa, Peter V., Choi, Mansoo
Format: Artikel
Sprache:eng
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Zusammenfassung:The size and crystalline phase changes of Fe2O3 nanoparticles formed in a H2/O2 flame have been investigated. At flame temperatures below 1350 °C, the mean particle size increased monotonously with the distance from the burner edge; but in high-temperature flames above 1650 °C, it suddenly decreased from 20 to ∼3 nm with the distance from the burner edge. The results of X-ray diffraction and high-resolution transmission electron microscopy showed that this sudden reduction of the size of nanoparticles was accompanied by a partial phase transformation from the metastable γ-Fe2O3 into α-Fe2O3. We suggest the structural instability due to γ- to α-phase transformation as a mechanism for a rapid fragmentation of 20 nm particles into 3 nm ones.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1632534