ISSN:
1573-4846
Keywords:
sol-gel
;
magnetic nanocomposite
;
iron oxide
;
Mössbauer spectroscopy
;
Kerr effect
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Magnetic nanocomposites γ-Fe2O3/silica were prepared by a one-step sol-gel method. The sol was prepared by TEOS (tetraethyl orthosilicate) acid hydrolysis in the presence of an iron salt soluble in methanol. After gelation and drying, the transparent samples were characterized after treatment at different temperatures. The particle size, observed by HR TEM, was in the range of 2–10 nm and depended on Fe-concentration and heating temperature. Magnetic measurements showed either a ferromagnetic or a superparamagnetic behaviour and could be explained by the particle size. The dependence of the magnetic behaviour on the particle size was also studied by Mössbauer spectroscopy. The samples in which the Fe2O3 particle size was approximately 10 nm showed magnetic splitting (sextet) at room temperature, while smaller particles (2–3 nm) showed this splitting only at the temperature of liquid helium. The optomagnetic properties of the samples were also measured (Kerr effect).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02436910
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