Structural and magnetic susceptibility studies of SiO2: Fe2O3 nano-composites prepared by sol–gel technique

γ-Fe2O3/SiO2 nanocomposites for magneto-optical applications: Nanostructural and magnetic properties

“…Many efforts have been addressed to avoid the appearance of hematite during the treatment of gel hosted ironoxide particles [27], showing very broad transition temperatures covering from 600 to about 900°C even for similar sample preparation. Such studies illustrate that, despite of the phase isolation attempts, the transformation strongly [39] 0.38 À0.21 52.1 -depends on the sample processing, and in all cases it has been found the eventual occurrence of hematite.…”

Synthesis and magnetic properties of concentrated α-Fe2O3 nanoparticles in a silica matrix

“…Various nanoparticles dispersed in a silica matrix have been successfully synthesized by the sol-gel method, such as Fe [26], Ni [27], ␥-Fe 2 O 3 [28], NiZn-ferrite [29] and ␣-Fe 2 O 3 [30]. Silica provides a convenient matrix for fundamental investigations because its cavities have a well-defined size and geometry, and they are also regularly arranged in space.…”

The thermal stability of maghemite-silica nanocomposites: An investigation using X-ray diffraction and Raman spectroscopy

“…Above this temperature, mixtures of -Fe 2 O 3 and ␣-Fe 2 O 3 phases can be obtained [10]. It must be pointed out that it is very difficult to obtain the pure -Fe 2 O 3 phase, but the management of the sol-gel processing with the aim of controlling the confinement of nanoparticles inside the pores of a silica xerogel is an opportunity to optimize the synthesis of this rare polymorph [13,14]. In this study, X-ray diffraction, FTIR and Micro-Raman spectroscopy were used to investigate the thermal stability of maghemite-silica nanocomposites and characterize the iron oxide phases in low and high nanoparticle containing samples.…”