F. Iglesias, J. Baughman, H. Bagramyan, C. Reynaga, J. Shallenberger, A. Khodagulyan, O. Bernal, A. Kocharian
California State University Los Angeles,
Keywords: core-shell iron-based magnetic nanoparticles annealed by oxygen and nitrogen at different temperatures
Summary:annealed by oxygen and nitrogen at different temperatures F. Iglesias, J. Baughman, H. Bagramyan, C. Reynaga, J. Shallenberger, A. Khodagulyan, O. Bernal, A. Kocharian 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 by XRD, XPS, Raman, SEM and HR TEM microscopy images, magnetometry and EPR measurements. In recent year we have synthesized and realized structural and magnetic investigation a number of Fe-Fe3O4 and Fe-Fe3C nanoalloys having “core-shell” architectures. TEM image of Fe-Fe3O4 “core-shell” nanoparticles (left) and corresponding heating rate (right). Under external electromagnetic field the magnetic heating of these materials shows unique properties, and they may consider promising materials for magnetic hyperthermia of cancer cells. Oxygen and nitrogen annealed phthalocyanine and porphyrin (graphene) can significantly influence magnetic properties as compared with those of pyrolysis of iron-based graphene. We investigate structural and magnetic properties of synthesized by a one-step process of thermal decomposition (Pyrolysis) of iron phthalocyanine (FePc) and iron porphyrin (FePr) nanoparticles of “core-shell” structure with the high magnetic moment of core (such as Fe), and the shell consists of a biocompatible material (e.g., iron oxide, iron nitride or carbide). We conducted investigations of structural and magnetic properties of these 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 oxygene and nitrogen content and structures are directly achieved from the XPS analysis. The measured magnetization of magnetic saturation and coercivity as well as the specific absorption rate (SAR) show that these materials attractive for magnetic hyperthermia medical applications. Hysteresis loop of the (Fe-Fe3C)@C and (Fe-Fe3O4)@C nanocomposites are of special interest because of high Mr/Ms ratio.