Influence of Atomic Doping on Thermal Stability of Ferrite Nanoparticles—Structural and Magnetic Studies

Abstract

In this paper, a series of experiments are reported where ferrite nanoparticles were synthesized with different substitution percentages (5, 10, 15, or 20%) of Fe2+ by Co2+, Mn2+, or Ni2+ ions. Afterwards, the prepared nanoparticles were thermally treated between 50 and 500 °C in air for 24 h in order to observe how doping influences the oxidation process induced by temperature elevation and access to O2. Nanoparticles were imaged before and after thermal treatment by transmission electron microscopy and were analyzed by X-ray diffraction, vibrating sample magnetometry, and Mössbauer spectroscopy. Presented studies reveal that the amount and kind of doped transition metals (of replaced Fe2+) strongly affect the oxidation process of ferrite nanoparticles, which can govern the application possibility. Each transition element suppresses the oxidation process in comparison to pure Fe-oxides, with the highest impact seen with Ni2+.

Efficient Green Synthesis of (Fe3O4) and (NiFe2O4) Nanoparticles Using Star Anise (Illicium verum) Extract and Their Biomedical Activity against Some Cancer Cells

“…Magnetic nanoparticles (MNPs) have been extensively investigated owing to their interesting properties, such as excellent magnetic activity, chemical and thermal stability, high surface-area-to-volume ratio, good adsorption behavior, and photocatalytic activity [ 1 , 2 , 3 , 4 ]. However, ferrite in the form of magnetite (Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), and doped-ferrite have particularly received a large amount of attention [ 5 , 6 , 7 ]. Generally, based on the crystal structure, ferrite nanoparticles are classified as hexagonal (MFe 12 O 19 ), garnet (M 3 Fe 5 O 12 ), or spinel (MFe 2 O 4 ) structures, where M is a transition metal cation such as Ni, Mg, Co, Cu, or Zn [ 8 , 9 ].…”

The Influence of Li+ and K+ Added Cations and Annealing Temperature on the Magnetic and Dielectric Properties of Mg-Zn Ferrite

“…The main inconvenience of spinel magnesium-based ceramic materials is their high annealing temperature, over 1300 °C, which causes significant material loss and large energy consumption. Magnetic and dielectric properties of ferrites can be enhanced or altered by modifying various added metallic cations and the sintering temperature and/or time [ 7 , 8 , 9 , 10 , 11 ]. Magnetic and dielectric properties of spinel ferrites AB 2 O 4 are also dependent on the distribution of A and B cations in tetrahedral or octahedral sites, respectively.…”