RUI: Synthesis, Structure, and Magnetic Studies of High Anisotropy Magnetic Nanocrystals

RUI：高各向异性磁性纳米晶体的合成、结构和磁性研究

• 批准号: 0514068
• 负责人: Kiumars Parvin
• 金额: $ 33万
• 依托单位: San Jose State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0514068&HistoricalAwards=false
• 关键词: RUI; Synthesis; Structure; Magnetic; Studies

TECHNICAL: This is a collaborative effort of three research groups at San Jose State University (physics, chemical engineering, and biology departments) focused on the synthesis, structure and magnetic studies of monodispersed nanocrystals with controlled assembly. This group has recently synthesized single element particles of ferromagnetic materials by a self-assembly method. This grant extends the research to include binary magnetic materials (FePd, FePt, CoPt, and MnAl) and ternary nanoparticles of these compounds with added Cu, Ag or Au to enhance the growth of L10 structure. Through chemical self-assembly one can control the ratio of two elements, nanocrystalline particle size, and lattice structure rendering magnetic materials with broad range of properties and applications. Addition of Ag, Au or Cu decreases the heating temperature required to transform the nanoparticle fcc phase to L10 phase with high anisotropy constant. Additionally, since the ordered phase of these nanocrystals form over a dimension of 10 - 500 nm, the growth of these nanocrystals inside patterned holes of a substrate grown by photolithography is explored. This provides variation of parameters associated with a new lattice structure as well as variation of the height and diameter of individual holes filled in the direction perpendicular to the substrate surface. Experimental work to be carried out includes structural studies such as TEM and XRD. Magnetic characterizations include magnetometry utilizing VSM and SQUID, AC susceptibility, magnetic force microscopy, and Mossbauer effect spectroscopy over a wide range of temperature and magnetic field. NONTECHNICAL: Broader Impacts resulting from the activity include a wide range of application of magnetic nanocrystalline materials in areas such as drug delivery, MRI contrast agents, ferrofluids, and storage technology. The capability to synthesize monodispersed nanocrystals with controlled size and lattice structure provides flexibility in growth of materials with desired properties. The PI and colleagues involved in the research have a long record of success in science and engineering education, research training, and outreach activities. MS level graduate and undergraduate students have been involved in all stages of past activities and will continue to contribute to the progress of research while enhancing their hands-on educational experience. Underrepresented groups in science and engineering such as women and minorities constitute 58% of student body at SJSU. In the student selection process effort will be made to involve the members of this group in the research activities.

技术支持：这是圣何塞州立大学（物理、化学工程和生物系）三个研究小组的合作成果，重点是具有受控组装的单分散纳米晶体的合成、结构和磁性研究。该小组最近通过自组装方法合成了铁磁材料的单元素颗粒。该资助将研究扩展到包括二元磁性材料（FePd，FePt，CoPt和MnAl）和这些化合物的三元纳米颗粒，并添加Cu，Ag或Au以增强L10结构的生长。通过化学自组装，人们可以控制两种元素的比例、纳米晶颗粒尺寸和晶格结构，从而使磁性材料具有广泛的性能和应用。添加Ag、Au或Cu降低了将纳米颗粒fcc相转变为具有高各向异性常数的L10相所需的加热温度。此外，由于这些纳米晶体的有序相在10 - 500 nm的尺寸上形成，因此探索了这些纳米晶体在通过光刻法生长的衬底的图案化孔内的生长。这提供了与新的晶格结构相关联的参数的变化以及在垂直于衬底表面的方向上填充的各个孔的高度和直径的变化。要进行的实验工作包括结构研究，如TEM和XRD。磁性表征包括利用VSM和SQUID，交流磁化率，磁力显微镜，穆斯堡尔效应光谱在很宽的温度和磁场范围内的磁力测量。非技术性：该活动产生的更广泛的影响包括磁性纳米晶材料在药物输送、MRI造影剂、铁磁流体和存储技术等领域的广泛应用。合成具有受控尺寸和晶格结构的单分散纳米晶体的能力为具有所需性能的材料的生长提供了灵活性。参与研究的PI和同事在科学和工程教育，研究培训和推广活动方面有着长期的成功记录。MS水平的研究生和本科生参与了过去活动的各个阶段，并将继续为研究的进展做出贡献，同时增强他们的实践教育经验。在科学和工程，如妇女和少数民族的代表性不足的群体构成学生在SJSU的58%。在学生选拔过程中，将努力让该组成员参与研究活动。