nanostructured samples of these compounds. The structural and magnetic characterization of the samples was realized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), PPMS (Physical Property Measurement System) for hysteresis cycles and FC (Field Cooling) and ZFC (Zero Field Cooling) scans and Mspectrometry (MS). The Rietveld refinement of the Fe-SiO 2 sample shows the presence of hematite and FeCl2(H2O)6 phases with enlarged crystallites of nanometric size. The corresponding SEM micrographies prove these crystallites are nanoparticles as well as that they form agglomerates. The MS shows the sextet of the hematite and a singlet which can be attributed to the iron chloride. The hysteresis cycle at room temperature (RT) is very thin, showing a soft magnetic behavior, and do not saturate, due the high paramagnetic presence of the iron chloride. The FC and ZFC scans show a peak of irreversibility at 16 K attributed to a spin-glass phase and then decreases with the temperature increase proving the soft ferromagnetic behavior at RT. The Ni-SiO2 sample shows the NiO and NiCl2(H2O)6 phases. The SEM observation shows big polycrystalline spherical particles and also nanometric monocrystalline particles. This sample does not show hysteresis cycle showing its paramagnetic character at RT. Finally the Co-SiO2 sample presents the Co3O4 and CoNiO phases and a paramagnetic character. However, the ZFC and FC scans show peaks at 31 K and then a decreasing signal as T increases and also an irreversibility temperature near 250 K. Behavior which can be associated to the existence of a pure spin-glass phase.