Characterization of synthesized iron-based core-shell nanoarchitectures in carbon matrix annealed by oxygen and nitrogen.

The carbon microspheres filled with clusters of few layer graphene nanostructures were produced by solid phase pyrolysis using as precursors a metal free porphyrin and phthalocyanine. The morphology, structure and size of multilayered graphene nanostructures were investigated using XRD, XPS, Raman, SEM and HR TEM microscopy images, magnetometry and EPR measurements. In recent years we have synthesized and realized structural and magnetic investigation of Fe-Fe₃O₄ and Fe-Fe₃C nanoalloys having “core-shell” architectures. Oxygen and nitrogen annealed phthalocyanine and porphyrin (graphene) influence magnetic properties as compared with those of pyrolysis of iron-based graphene. We conducted investigations of structural and magnetic properties of materials annealed by oxygen and nitrogen at different temperatures using X-ray diffraction (XRD), measurements of XPS spectra, high resolution SEM/STEM images, magnetometry PPMS measurements. The measured magnetization of magnetic saturation and coercivity as well as the specific absorption rate (SAR) show that these materials are attractive for magnetic hyperthermia medical applications. Under external electromagnetic fields the magnetic heating of these materials shows unique properties, and they may consider promising materials for magnetic hyperthermia of cancer cells. Hysteresis loop of the (Fe-Fe₃C)@C and (Fe-Fe₃O₄)@C nanocomposites are of special interest because of high Mr/Ms ratio.