Nanostructural Evolution and Magnetic Response in the Oxidation of FeCo Nanomaterials

点击翻译按钮获取中文摘要

TECHNICAL: PI?s plan to conduct research on synthesis, structure, properties and performance relationships in magnetic nanoparticles (MNPs) having promise for applications in RF absorption, medicine, RF heating and ferrogels with unique magnetomechanical response. The intellectual merit of the work lies in: (1) furthering understanding of nanostructural evolution, oxidation products and rates of FeCo/ferrite nanocomposite materials and (2) the relationship of nanostructure (including surface and interface crystallography, metal and oxide volume fractions, thermodynamics of small particles and composition) with high frequency switching of MNPs, ferrofluids and composites. Research objectives are to develop fundamental understanding of magnetic metal/oxide core shell structures in terms of: (a) understanding the sequence of oxide formation and epitaxial relationships with polyhedral facetted magnetic FeCo nanoparticles; (b) modeling chemical partitioning occurring in oxidation and it?s role in developing surface and interfacial anisotropy in MNPs; (c) microstructural observations and magnetic properties measurements to determine anisotropy mechanisms which control Neel relaxation processes and (d) the role of Neel relaxation in the RF field activated heating of 2-phase FeCo/ferrite MNPs. This work couples with collaborations with the Pittsburgh Hillman Cancer Research Center to develop RF heating of nanoparticles for thermoablative cancer therapy and the Pittsburgh McGowan Tissue Engineering Center to develop magnetic tagging of tissue scaffolds and ferrogel magnetomechanical response for the same. NON-TECHNICAL: The potential for broad impact lies in the materials having promise in RF heating of fluids, polymers and epoxies. The work will further understanding of nanostructural development and control of magnetothermal response in these applications. Efficient point source heating of nanoparticles can be exploited for thermoablative cancer therapies and to promote attachment to tissue scaffolds if adherent, biocompatible oxide shells can be engineered and functionalized with appropriate surfactants to stabilize aqueous ferrofluids and antibodies to promote cell or tissue attachment. Work will be disseminated in publications and presentations at the MMM and materials conferences (MRS and/or TMS). Interactions and collaborations will also aid broad dissemination. We will interact with K. Hono of NRIM for field ion microscopy and Monica Sorescu of Duquesne Univ. for Mossbauer spectroscopy. Research will couple to educational initiatives. The PI?s have offered (2007) an undergraduate (UG) course ?Structure, Properties and Performance Relationships in Magnetic Materials? following a decade teaching the graduate course ?Applied Magnetism and Magnetic Materials? in the CMU Materials Science and Engineering (MSE) Dept. The PI?s have developed Powerpoint modules (2007) and distributed 350 pages of chapters through the CMU Blackboard system. These will be extended with the aim of publishing an UG Magnetic Nanomaterials text. The PI?s will continue a long history of sponsoring UG research projects (with many women and minority students), during this project.