Abstract by Johnathon Rackham
Physics and Astronomy
Modeling magnetic correlations in magnetite nanoparticle assemblies using x-ray magnetic scattering data
Magnetic nanoparticles are increasingly used in nanotechnologies and biomedical applications, such as drug targeting, MRI, and bio-separation. Magnetite nanoparticles stand to be effective in these roles due to the non-toxic nature of magnetite and its ease of manufacture. To be more effective in these application we need a greater understanding of the magnetic behavior of the individual magnetite nanoparticles when a collection of them is used. This research seeks to discover the local magnetic ordering of ensembles of nanoparticles occuring at various stages of the magnetization process. To do such we use resonant x-ray magnetic scattering which provides information about the magnetic orders in the material. Here we discuss the modeling of the magnetic scattering data using a on-dimensional chain of nanoparticles with a mix of ferromagnetic, anti-ferromagnetic, and random order. The model uses twelve variable paramters and is optimized through a Levenberg-Mardquardt algorithm to find the best fit parameters. By fiting the model to the experimental data, we extract information about the magnetic correlations in the nanoparticle assembly.