Abstract by Johnathon Rackham
Physics and Astronomy
Modeling magnetic correlations in magnetite nanoparticle assemblies using x-ray magnetic scattering data
Magnetite (Fe3O4) nanoparticles are increasingly used in nanotechnologies and biomedical applications, such as drug targeting, MRI, bio-separation. To be more effective in these applications, a greater understanding of the inter-particle magnetic correlation is needed, in particular when a collection of superparamagnetic nanoparticles is used. This research seeks to discover the local magnetic ordering of ensembles of magnetite nanoparticles occurring at various stages of the magnetization process. We use resonant x-ray resonant magnetic scattering (XRMS), which provides information about the magnetic orders in the material. The modeling of the magnetic scattering data uses a one-dimensional chain of nanoparticles with a mix of ferromagnetic, anti-ferromagnetic, and random order. The model utilizes twelve variable parameters and we used a Levenberg-Mardquardt algorithm to find the best fit parameters. By fitting the model to the experimental data, we extracted information about the magnetic correlations in the nanoparticle assembly.