Nanostructural Evolution and Magnetic Response in the Oxidation of FeCo Nanomaterials

技术:π?计划开展磁性纳米颗粒（MNPs）的合成、结构、性质和性能关系的研究，该纳米颗粒有望应用于射频吸收、医学、射频加热和具有独特磁机械响应的铁凝胶。本研究的知识价值在于：(1)进一步了解FeCo/铁氧体纳米复合材料的纳米结构演化、氧化产物和氧化速率；(2)纳米结构（包括表面和界面晶体学、金属和氧化物体积分数、小颗粒热力学和组成）与MNPs、铁磁流体和复合材料的高频开关之间的关系。研究目标是在以下方面发展对磁性金属/氧化物核壳结构的基本认识：(a)了解氧化物形成的顺序以及与多面体面状磁性FeCo纳米颗粒的外延关系；(b)模拟氧化和它？在MNPs中形成表面和界面各向异性的作用；(c)微观结构观察和磁性能测量，以确定控制Neel弛豫过程的各向异性机制；(d) Neel弛豫在RF场激活加热两相FeCo/铁氧体MNPs中的作用。这项工作还与匹兹堡希尔曼癌症研究中心合作，开发用于热烧蚀癌症治疗的射频加热纳米颗粒，并与匹兹堡麦高恩组织工程中心合作，开发组织支架的磁标记和铁凝胶磁力学响应。非技术：广泛影响的潜力在于在流体、聚合物和环氧树脂的射频加热方面有前景的材料。这项工作将进一步理解纳米结构的发展和磁热响应的控制在这些应用中。纳米颗粒的高效点源加热可以用于热烧蚀癌症治疗，并促进与组织支架的附着，如果粘附，生物相容性氧化物外壳可以用适当的表面活性剂进行工程设计和功能化，以稳定水铁磁流体和抗体，以促进细胞或组织的附着。工作成果将在MMM和材料会议（MRS和/或TMS）的出版物和演讲中传播。相互作用和合作也将有助于广泛传播。我们将与NRIM的K. Hono进行场离子显微镜和Duquesne大学的Monica Sorescu进行穆斯堡尔光谱研究。研究将与教育举措相结合。π吗?我们在2007年开设了本科（UG）课程？磁性材料的结构、性质和性能关系？教了十年研究生课程？应用磁学与磁性材料？CMU材料科学与工程（MSE）系的PI？我们开发了Powerpoint模块（2007年），并通过CMU Blackboard系统分发了350页的章节。这些将扩展与出版UG磁性纳米材料文本的目的。π吗?在这个项目期间，我们将继续赞助UG的研究项目（有许多女性和少数民族学生）。

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.