Solopan S. Synthesis, structure and properties of nanoscale magnetic systems based on oxide compounds with spinel and perovskite structures

The dissertation is devoted to the synthesis of nanosized ferromagnetic materials (weakly agglomerated nanoparticles, core/shell structures) with the structure of spinel and perovskite, the creation of composite structures based on them, the study of their properties (structural, magnetic, etc.) and the possibility of practical use in medicine. magnetic hyperthermia and in the technique of microwave communication. The study of chemical processes that occur in the synthesis of weakly agglomerated ferromagnetic nanosized particles with the structure of spinel AFe2O4 (A = Mn, Fe, Co, Ni, Zn) and perovskite (La,Sr)MnO3 obtained by different methods (precipitation from non-aqueous solution, deposition from inverted microemulsions by cryochemical and sol-gel methods). Synthesis and properties of core/shell structures (Fe3O4/CoFe2O4) with different shell thicknesses - 1, 2.5 and 3.5 nm were investigated. Core/shell nanostructures based on nanoparticles (La,Sr)MnO3 with organic (polysorbate 80, L-proline and polyethylene glycol) and inorganic (SiO2) substances were synthesized. It is established that the synthesized nanosized particles in particular with the structure of perovskite (La,Sr)MnO3 can be used both in medicine, as inducers of magnetic hyperthermia and in engineering. It has been shown for the first time that under certain conditions such materials exhibit left-handed properties. Composite resonant microwave elements have been developed on the basis of nanoparticles of nickel-zinc ferrites Ni0.5Zn0.5Fe2O4, in which it is shown for the first time that it is possible to control their resonant frequency by an external constant magnetic field.