Effect of dopant on the thermal stability of core-shell ferrite nanoparticles

In this study, a series of core-shell ferrite nanoparticles were obtained by the thermal decomposition method of iron(III) acetylacetonate. Various amounts of Co3', Mn3', or Ni2' ions as dopants were used. The prepared nanoparticles were treated at 500 & DEG;C for 24 h in the air atmosphere to determine the influence of doping on magnetite/maghemite crystalline structure and the following oxidation process. The nanoparticles before and after thermal treatment were evaluated by transmission electron microscopy, energy dispersive X-ray, X-ray diffraction and Mossbauer spectroscopy. The conducted studies show that doping primary structures by different 3d elements modulates the oxidation process of ferrite nanoparticles which, therefore, gives new possibilities for their application. However, the resistance to the oxidation of layered particles is different in comparison to the one-pot synthesis procedure. The susceptibility to oxidation varies not only due to the presence of different dopants in variable concentrations, but it also is dependent on layer positioning in the particle (core, shell, or both). The most protective element is Mn, and the least one - Co.& COPY; 2023 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.