| | 1 | Author
| Carla Cannas, Giorgio Concas, Anna Musinu, Giorgio Piccaluga, Giorgio Spano | Requires cookie* | | | Title
| Mössbauer Spectroscopic Study of Fe 2 0 3 Nanoparticles Dispersed over a Silica Matrix  | | | | Abstract
| A series of Fe 2 0 3 -Si02 nanocomposites (9 -33 wt% of Fe 2 0 3) has been prepared by a sol-gel method and submitted to thermal treatments at 300 -900 °C. The samples were characterized by X-ray diffraction and Mössbauer Spectroscopy measurements. Superparamagnetic behavior is exhibited by all the samples, indicating that the size of iron oxide grains is in the nanometer range (4-6 nm). Increase of iron content and temperature treatment give rise to a small particle growth, while the spread of sizes around the average value increases with the iron concentration. The Mössbauer spectra, at all the explored compositions, show a very steep increase of the peak width by treatment temperature at 900 °C, indicating the formation of the ferrimagnetic 7-Fe 2 0 3 phase from the antiferromagnetic amorphous Fe 2 0 3 phase, which dominates in the samples treated at lower temperatures. The samples at 28.5% and 33.2%, treated at 900 °C, also show a component of 7-Fe 2 0 3 in the blocked state at room temperature. Moreover, the growth of the particles favours the formation of other oxide phases (a and £ phase) along with the 7 phase. | | | |
Reference
| Z. Naturforsch. 54a, 513—518 (1999); received June 28 1999 | | | |
Published
| 1999 | | | |
Keywords
| Nanocomposite, Ferric Oxide, Mössbauer Spectroscopy, X-ray Diffraction | | | |
Similar Items
| Find | | | DEBUG INFO
| | | | | TEI-XML for
| default:Reihe_A/54/ZNA-1999-54a-0513.pdf | | | | Identifier
| ZNA-1999-54a-0513 | | | | Volume
| 54 | |
|
