In recent years there is a growing interest in synthesizes of novel iron-based nanoparticles and nanocomposites with high efficiency of thermal energy transfer suitable for use in magnetic fluid hyperthermia. The development of novel biocompatible magnetic nanoparticles (MNPs) for biomedical applications has been the subject of extensive exploration over the past two decades. Here we study the characteristics of carbon-coated ferromagnetic (Fe-Fe3O4)@C “core-shell” nanoparticles in samples with different concentration of iron synthesized by a solid-phase pyrolysis (SPP) of iron phthalocyanine (FeC32H16N8) molecules. The sample with higher iron concentration additionally annealed at 250°C under the oxygen media produces (Fe3O4) shell on Fe nanoparticles. The structural and magnetic properties of these nanomaterials were conducted using Scanning Electron Microscope (SEM), High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images with elemental mapping data, Raman spectroscopy, X-ray diffraction (XRD), magnetometry, electron paramagnetic and ferromagnetic resonances (EPR, FMR). The STEM image in Fig. 1 demonstrates a presence of Fe-Fe3O4 “core-shell” nanoparticles of order ~ 50 nm with oxide shells in carbon matrix. The ferromagnetic hysteresis loops with residual magnetizations and coercive forces is shown in Fig. 2 at two different temperatures. The characteristics of magnetic heating of water-based solution with different concentrations of synthesized nanocomposites under the influence of an external magnetic field have been studied. The magnetic characteristics such as saturation magnetization and coercivity as well as the specific absorption rate (SAR) make these materials attractive for magnetic hyperthermia applications.This work was supported by European Union’s Horizon 2020 research and innovation programme under grant agreement No 857502 (MaNaCa). The work at CSULA supported by the NSF CREST Grant #HRD-1547723.
Fig. 1 High-resolution transmission electron microscopy images of iron/iron-oxide nanoparticles with core-shell architecture embedded in carbon matrix
Fig. 2 Magnetization versus magnetic field shown for Fe-Fe3O4 nanoparticles at 3K and 300K