| Autor: |
Gurgel, A. L., Soares, J. M., Chaves, D. S., Xavier Jr., M. M., Morales, M. A., Baggio-Saitovitch, E. M. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; May2010, Vol. 107 Issue 9, p09A746-1-09A746-3, 3p |
| Abstrakt: |
In this paper we report the synthesis and magnetic properties of CoFe2O4 nanoparticles. The nanoparticles with sizes ranging from 6 to 20 nm were prepared in a chitosan matrix. Size selection was achieved by introducing a nonionic surfactant Tween-X, where X={20, 60, 80, and 85}. Aqueous dispersions of Tween-X show micelles with increasing hydrodynamic sizes as X increases. Mössbauer spectroscopy measurements at 300 K show superparamagnetic behavior for the small particles, changing gradually to a blocked magnetic regime as the particle size increases. Magnetization measurements at 300 K show increasing values for the ratio Mr /MHmax and coercive fields (Hc). [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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