Carbon-coated iron oxide nanoparticles: A pathway to enhanced magnetic performance and hyperthermia applications

We report the development of carbon-coated iron oxide nanoparticles (IONPs@C) core–shell nanoparticles that harness an eco-friendly synthesis to achieve outstanding magnetic and thermal performance for magnetic hyperthermia with applications in cancer therapy. Comprehensive characterization via transmission electron microscopy (TEM), scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and complementary spectroscopic techniques has unveiled a notable nanostructural evolution: the pristine IONPs particles (M1) exhibit an average size of 15 ± 8 nm, which notably expands to 31 ± 9 nm upon carbon coating (M2). This structural transformation, marked by preserved crystallinity in cubic spinel configuration, directly correlates with a significant boost in magnetic performance. Notably, saturation magnetization increases from 121 emu/g Fe to 128 emu/g Fe , while the specific absorption rate (SAR) escalates from 232 to 502 W/g Fe under an alternating magnetic field of 260 kHz and 52 kA/m. Our results reveal that combining eco-friendly synthesis with comprehensive structural analysis not only generates nanomaterials of exceptional performance, but also opens up new paths for groundbreaking therapeutic innovations through advancements in condensed matter approaches. • • Amorphous carbon coating significantly enhances the magnetic response of iron oxide nanoparticles by reducing surface spin disorder. • • A clear correlation between interfacial structure, saturation magnetization, and radio-frequency magnetic losses is experimentally demonstrated. • • Carbon-coated nanoparticles exhibit up to a twofold increase in specific absorption rate under identical alternating magnetic field conditions.