Quantitative analysis of iron oxide particles embedded in an amorphous xerogel matrix

Using DTA, X-ray diffraction, vibrating sample magnetometry, and Rietveld refinement, we analyze the structural evolution under thermal treatment, and its relation to magnetic properties, of the compound formed by iron oxide particles embedded in a silica xerogel matrix. A variation of the Rietveld refinement method is used to calculate the amorphous and crystalline content in these composites by considering an initial crystalline model assumed to be the same composition as the material to be modelled. We refined the structure of compounds using the Maud program and we found that this program can be used to determine the amorphous and crystalline fractions of composites. Structural changes are correlated with magnetic properties.