Magnetic order and fluctuation of Fe3O4 nanoparticles

Magnetite (Fe$_{3}$O$_{4})$ nanoparticles tend to self-assemble when they are deposited on a substrate. Our goal is to understand the magnetic order and magnetic interactions between the particles, when they are self-assembled. After bulk structural and magnetic characterizations, we have been studying our Fe$_{3}$O$_{4}$ nanoparticles by using X-ray Magnetic Circular Dichroism (XMCD) as well as X-ray Resonant Magnetic Scattering (XRMS) at synchrotron radiation facilities. Both techniques utilize the interaction between magnetic spins in the material and polarized light. The XMCD can identify the L$_{2}$ and L$_{3}$ edges and gives information about the average magnetization in the material. We set our X-ray energy at the L3 edge and collect the XRMS scattering pattern. The XRMS scattering pattern shows information about the magnetic order and magnetic fluctuations in the nanoparticles assembly.~By studying the profile of the XRMS patterns, we~try to extract the magnetic signal from the charge signal, and learn about the magnetic order between the nanoparticles. We also utilize the coherence of the X-ray light and apply a correlation spectroscopy technique to learn about magnetic fluctuations.