Spectroscopic properties of γ-irradiated FemOn–SiO2 composite nanoparticles

Resumo

The colloidal solutions and deposited layers of Fe_mO_n–SiO₂ composite particles were studied. The colloidal solutions were prepared by precipitation of Fe_mO_n on the surface of porous silicon dioxide particles synthesized from a tetraethoxysilane (TEOS) alcohol solution by the sol‒gel method. It was found that, in the visible and near-UV ranges of the absorption spectra, there are six bands typical of conglomerates of FemOn nanoparticles. The investigation of Raman spectra of the samples subjected to laser annealing and γ-irradiation revealed the phase transitions Fe₃O₄ → γ-Fe₂O₃ → α-Fe₂O₃.