Currently, superparamagnetic functionalized systems of magnetite (Fe₃O₄) nanoparticles (NPs) are promising options for applications in hyperthermia therapy, drug delivery and diagnosis. Fe₃O₄ NPs below 20 nm have stable single domains (SSD), which can be oriented by magnetic field application. Dispersion of Fe₃O₄ NPs in silicon dioxide (SiO₂) matrix allows local SSD response with uniaxial anisotropy and orientation to easy axis, 90° or 180° . A successful, easy methodology to produce Fe₃O₄ NPs (6–17 nm) has been used with the Stöber modification. NPs were embedded in amorphous and biocompatible SiO₂ matrix by mechanical stirring in citrate and tetraethyl orthosilicate (TEOS). Fe₃O₄ NPs dispersion was sampled in the range of 2–12 h to observe the SiO₂ matrix formation as time function. TEM characterization identified optimal conditions at 4 h stirring for separation of SSD Fe₃O₄ in SiO₂ matrix. Low magnetization (M_s) of 0.001 emu and a coercivity (H_c) of 24.75 Oe indicate that the embedded SSD Fe₃O₄ in amorphous SiO₂ reduces the M_s by a diamagnetic barrier. Magnetic force microscopy (MFM) showed SSD Fe₃O₄ of 1.2 nm on average embedded in SiO₂ matrix with uniaxial anisotropy response according to Fe³⁺ and Fe²⁺ electron spin coupling and rotation by intrinsic Neél contribution.

Polycrystalline transparent Zinc oxide thin films have been grown on glass substrates by the sol–gel technique using two different precursor solutions. The physical properties of the films were analyzed with X-ray diffraction, Atomic Force Microscopy, UV–Vis and Raman spectroscopy. The results show that the films grew in the hexagonal wurtzite structure. The band gap of the samples was estimated from UV–Vis measurements in values from 3.1 to 3.22eV, these values are in agreement with those reported in the literature. Two different simple ways to obtain polycrystalline ZnO were developed and the properties of the films were studied as a function of the precursor solution