Time-Correlation of Magnetite Nanoparticle to determine dynamics of fluctuations through superparamagnetic transition

Magnetic nanoparticles have possible uses in many fields, including industry and medicine. To help facilitate their use and ensure their stability in time, we are investigating the magnetic properties of Fe₃O₄ (magnetite) nanoparticles, specifically the dynamics of magnetic fluctuations throughout the superparamagnetic transition, below which the nanoparticle spins are magnetically frozen. We accomplish this by cross-correlating x-ray scattering speckle patterns collected at successive times and at various temperatures. The data was collected using synchrotron radiation. Here I will show how we address instability issues in data collection. By developing a homemade cross-correlation process, based on Fourier transforms, and by adjusting the integration area of the correlation signal, and tracking spatial shifts, we show that we can recover the physical superparamagnetic transition signal, even when hidden in instrumental noise.