FeO Nanoparticles Doped with Gd: Phase Transformations as a Result of Thermal Annealing.

The aim of this work is to study the effect of the phase composition of the synthesized FeO-GdO nanoparticles on the efficiency of using magnetic hyperthermia as a basis for experiments. This class of structures is one of the most promising materials for biomedical applications and magnetic resonance imaging. In the course of the study, the dynamics of phase transformations of nanoparticles FeO → FeO/GdFeO → GdFeO were established depending on the annealing temperature. It has been determined that the predominance of the GdFeO phase in the structure of nanoparticles leads to an increase in their size from 15 to 40 nm. However, during experiments to determine the resistance to degradation and corrosion, it was found that GdFeO nanoparticles have the highest corrosion resistance. During the hyperthermal tests, it was found that a change in the phase composition of nanoparticles, as well as their size, leads to an increase in the heating rate of nanoparticles, which can be further used for practical purposes.