RUI: Magnetic morphologies and excitations in ferrite nanoparticle assemblies

Oberlin College, Oberlin OH

Investigators

Abstract

Non-technical Abstract Magnetic nanoparticles are tiny magnets which are being used for targeted drug delivery, biomedical imaging, data storage, environmental remediation, and many other technologies. These applications all depend critically on the specific manner in which the magnetic particles align and interact with each other. However, it has been difficult to determine these arrangements with standard experimental equipment, and it was even more difficult to optimize particles for applications. This project addresses this significant problem by helping to develop and promote the use of advanced neutron scattering techniques at the National Institute of Standards and Technology (NIST) Center for Neutron Research. The research capitalizes on recent upgrades in the capabilities of American neutron scattering facilities to probe several key features of magnetic nanoparticle arrangements. Another important aspect of this work is the extensive training of undergraduate students at Oberlin College, a four-year liberal arts institution with a long history of fostering diversity and integrating teaching and research. This project is closely tied to the Principal Investigator's teaching assignments as well as her mentoring and outreach activities. Technical Abstract The specific experiments are focused on quantifying the nature of the magnetic spin arrangements and excitations in ferrite nanoparticle assemblies. The goals of the research are 1) to determine magnetic morphologies as a function of changes in chemical composition, particle diameter, and surface solubility and 2) to determine magnetic energy parameters that characterize spin excitations. The magnetic nanoparticles are being synthesized using solution chemistry and ligand exchange techniques. X-ray scattering, transmission electron microscopy, magnetometry, and magnetic fluid flow fractionation approaches are being used to optimize the samples. The PI and her students have been performing unusual polarization-analyzed small angle neutron scattering and inelastic neutron scattering experiments at the NIST Center for Neutron Research. The work involves collaborating with scientists at a variety of institutions representing academia (Case Western Reserve University and Carnegie Mellon University), industry (Cambrian Technologies), and government (NIST).