Structural, magnetic and hyperfine characterization of ZnxFe3-xO4 nanoparticles prepared by sol-gel approach via inorganic precursors

Structural characteristics and magnetic properties' of ZnxFe3-xO4 (where x = 0; 0.09; 0.18; 0.45; 1) nanoparticles were studied with X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR) and vibrating sample magnetometry (VSM). Oxidation of Fe2+ ions, redistribution of Zn2+ and Fe3+ ions between octahedral and tetrahedral sites, and the formation of cation vacancies in spinel-type cubic structure of the obtained ZnxFe3-x-y square O-y(4) substitutional solid solutions were revealed by Fe-57 Mossbauer spectroscopy. The nano particles synthesized via a modified sol-gel method using inorganic precursors have a size of 4-10 nrn, single-phase composition, superparamagnetic behavior at room temperature (300 K) and a relatively hydrophilic surface to form stable aqueous suspensions. The maximum magnetization of 59 emu/gat 300 K corresponds to Zn0.18Fe2.82O4 composition. The listed features make the materials promising candidates for various biological and medical applications such as contrast-enhanced magnetic resonance imaging, hyperthermia of pathological tissues, controlled drug release, and separation of nucleic acids.