Magnetic aerogels with very low volume density of ~0.2 g/cm3 were prepared by sol-gel method and supercritical drying. The resulting materials were monolithic and displayed high surface area. By X-ray diffraction and Mössbauer spectroscopy the crystalline phase formed inside the mesopores of the SiO2 matrix was identified as a spinel iron oxide. Comparison of the magnetic measurements with Mössbauer spectra at various temperatures contributed to the elucidation of the magnetic state of this nanocomposite system with restricted magnetic interactions, in particular its transition to a superparamagnetic state. © Springer Science + Business Media B.V. 2006.
|Publication status||Published - 1 Sep 2005|
- Fe O 2 3
- Mössbauer spectroscopy
- Superparamagnetic state