Effect of doping on structure and functional properties of SrFe12-xInxO19 hexaferrite nanoparticles for biomedical applications

Ceramics International. 2026. Vol. 52. No. 3. P. 3500–3511.

Shchetinin I., Nikolenko P., Nizamov T., Novikov A., Ivanova A., Alexey I. Kartsev

In this work, we comprehensively investigated the influence of Indium doping on the structure, magnetic and functional properties of strontium M-type hexaferrites SrFe12-xInxO19 nanoparticles (where x = 1.7, 1.8, 2.0). Colloidally stable SrFe12-xInxO19 nanoparticles (∼10 nm) were synthesized using a combination of the citrate method and high-energy ball milling. We demonstrate that doping reduces both the specific saturation magnetization and, especially, the coercivity to values compatible with high-frequency fields used in biomedicine. This enables the potential use of SrFe12-xInxO19-based materials as hyperthermia agents. The materials, when coated with Pluronic F-127 polymer, exhibited low cytotoxicity, supporting their biomedical applicability. The SLP parameters of the synthesized samples ranged from 3.5 to 6.4 W/g and depended on the doping level. Importantly, the materials possess a heating limit of 42–52 °C, eliminating the risk of overheating healthy tissues during hyperthermia. This maximum heating temperature results from a strong reduction in the Curie temperature induced by Indium doping. Furthermore, a complete correlation between the areas of the minor magnetic hysteresis loops and the SLP parameters indicates that heating under an alternating magnetic field is primarily due to remagnetization losses.

Keywords: magnetic nanoparticles, ab initio