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

San Jose State University Foundation, San Jose CA

Investigators

Abstract

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.